xref: /sqlite-3.40.0/src/main.c (revision 9e5ecdc1)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Main file for the SQLite library.  The routines in this file
13 ** implement the programmer interface to the library.  Routines in
14 ** other files are for internal use by SQLite and should not be
15 ** accessed by users of the library.
16 */
17 #include "sqliteInt.h"
18 
19 #ifdef SQLITE_ENABLE_FTS3
20 # include "fts3.h"
21 #endif
22 #ifdef SQLITE_ENABLE_RTREE
23 # include "rtree.h"
24 #endif
25 #if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
26 # include "sqliteicu.h"
27 #endif
28 #ifdef SQLITE_ENABLE_JSON1
29 int sqlite3Json1Init(sqlite3*);
30 #endif
31 #ifdef SQLITE_ENABLE_STMTVTAB
32 int sqlite3StmtVtabInit(sqlite3*);
33 #endif
34 #ifdef SQLITE_ENABLE_FTS5
35 int sqlite3Fts5Init(sqlite3*);
36 #endif
37 
38 #ifndef SQLITE_AMALGAMATION
39 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
40 ** contains the text of SQLITE_VERSION macro.
41 */
42 const char sqlite3_version[] = SQLITE_VERSION;
43 #endif
44 
45 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
46 ** a pointer to the to the sqlite3_version[] string constant.
47 */
48 const char *sqlite3_libversion(void){ return sqlite3_version; }
49 
50 /* IMPLEMENTATION-OF: R-25063-23286 The sqlite3_sourceid() function returns a
51 ** pointer to a string constant whose value is the same as the
52 ** SQLITE_SOURCE_ID C preprocessor macro. Except if SQLite is built using
53 ** an edited copy of the amalgamation, then the last four characters of
54 ** the hash might be different from SQLITE_SOURCE_ID.
55 */
56 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
57 
58 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
59 ** returns an integer equal to SQLITE_VERSION_NUMBER.
60 */
61 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
62 
63 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
64 ** zero if and only if SQLite was compiled with mutexing code omitted due to
65 ** the SQLITE_THREADSAFE compile-time option being set to 0.
66 */
67 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
68 
69 /*
70 ** When compiling the test fixture or with debugging enabled (on Win32),
71 ** this variable being set to non-zero will cause OSTRACE macros to emit
72 ** extra diagnostic information.
73 */
74 #ifdef SQLITE_HAVE_OS_TRACE
75 # ifndef SQLITE_DEBUG_OS_TRACE
76 #   define SQLITE_DEBUG_OS_TRACE 0
77 # endif
78   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
79 #endif
80 
81 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
82 /*
83 ** If the following function pointer is not NULL and if
84 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
85 ** I/O active are written using this function.  These messages
86 ** are intended for debugging activity only.
87 */
88 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
89 #endif
90 
91 /*
92 ** If the following global variable points to a string which is the
93 ** name of a directory, then that directory will be used to store
94 ** temporary files.
95 **
96 ** See also the "PRAGMA temp_store_directory" SQL command.
97 */
98 char *sqlite3_temp_directory = 0;
99 
100 /*
101 ** If the following global variable points to a string which is the
102 ** name of a directory, then that directory will be used to store
103 ** all database files specified with a relative pathname.
104 **
105 ** See also the "PRAGMA data_store_directory" SQL command.
106 */
107 char *sqlite3_data_directory = 0;
108 
109 /*
110 ** Initialize SQLite.
111 **
112 ** This routine must be called to initialize the memory allocation,
113 ** VFS, and mutex subsystems prior to doing any serious work with
114 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
115 ** this routine will be called automatically by key routines such as
116 ** sqlite3_open().
117 **
118 ** This routine is a no-op except on its very first call for the process,
119 ** or for the first call after a call to sqlite3_shutdown.
120 **
121 ** The first thread to call this routine runs the initialization to
122 ** completion.  If subsequent threads call this routine before the first
123 ** thread has finished the initialization process, then the subsequent
124 ** threads must block until the first thread finishes with the initialization.
125 **
126 ** The first thread might call this routine recursively.  Recursive
127 ** calls to this routine should not block, of course.  Otherwise the
128 ** initialization process would never complete.
129 **
130 ** Let X be the first thread to enter this routine.  Let Y be some other
131 ** thread.  Then while the initial invocation of this routine by X is
132 ** incomplete, it is required that:
133 **
134 **    *  Calls to this routine from Y must block until the outer-most
135 **       call by X completes.
136 **
137 **    *  Recursive calls to this routine from thread X return immediately
138 **       without blocking.
139 */
140 int sqlite3_initialize(void){
141   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
142   int rc;                                      /* Result code */
143 #ifdef SQLITE_EXTRA_INIT
144   int bRunExtraInit = 0;                       /* Extra initialization needed */
145 #endif
146 
147 #ifdef SQLITE_OMIT_WSD
148   rc = sqlite3_wsd_init(4096, 24);
149   if( rc!=SQLITE_OK ){
150     return rc;
151   }
152 #endif
153 
154   /* If the following assert() fails on some obscure processor/compiler
155   ** combination, the work-around is to set the correct pointer
156   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
157   assert( SQLITE_PTRSIZE==sizeof(char*) );
158 
159   /* If SQLite is already completely initialized, then this call
160   ** to sqlite3_initialize() should be a no-op.  But the initialization
161   ** must be complete.  So isInit must not be set until the very end
162   ** of this routine.
163   */
164   if( sqlite3GlobalConfig.isInit ){
165     sqlite3MemoryBarrier();
166     return SQLITE_OK;
167   }
168 
169   /* Make sure the mutex subsystem is initialized.  If unable to
170   ** initialize the mutex subsystem, return early with the error.
171   ** If the system is so sick that we are unable to allocate a mutex,
172   ** there is not much SQLite is going to be able to do.
173   **
174   ** The mutex subsystem must take care of serializing its own
175   ** initialization.
176   */
177   rc = sqlite3MutexInit();
178   if( rc ) return rc;
179 
180   /* Initialize the malloc() system and the recursive pInitMutex mutex.
181   ** This operation is protected by the STATIC_MASTER mutex.  Note that
182   ** MutexAlloc() is called for a static mutex prior to initializing the
183   ** malloc subsystem - this implies that the allocation of a static
184   ** mutex must not require support from the malloc subsystem.
185   */
186   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
187   sqlite3_mutex_enter(pMaster);
188   sqlite3GlobalConfig.isMutexInit = 1;
189   if( !sqlite3GlobalConfig.isMallocInit ){
190     rc = sqlite3MallocInit();
191   }
192   if( rc==SQLITE_OK ){
193     sqlite3GlobalConfig.isMallocInit = 1;
194     if( !sqlite3GlobalConfig.pInitMutex ){
195       sqlite3GlobalConfig.pInitMutex =
196            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
197       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
198         rc = SQLITE_NOMEM_BKPT;
199       }
200     }
201   }
202   if( rc==SQLITE_OK ){
203     sqlite3GlobalConfig.nRefInitMutex++;
204   }
205   sqlite3_mutex_leave(pMaster);
206 
207   /* If rc is not SQLITE_OK at this point, then either the malloc
208   ** subsystem could not be initialized or the system failed to allocate
209   ** the pInitMutex mutex. Return an error in either case.  */
210   if( rc!=SQLITE_OK ){
211     return rc;
212   }
213 
214   /* Do the rest of the initialization under the recursive mutex so
215   ** that we will be able to handle recursive calls into
216   ** sqlite3_initialize().  The recursive calls normally come through
217   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
218   ** recursive calls might also be possible.
219   **
220   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
221   ** to the xInit method, so the xInit method need not be threadsafe.
222   **
223   ** The following mutex is what serializes access to the appdef pcache xInit
224   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
225   ** call to sqlite3PcacheInitialize().
226   */
227   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
228   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
229     sqlite3GlobalConfig.inProgress = 1;
230 #ifdef SQLITE_ENABLE_SQLLOG
231     {
232       extern void sqlite3_init_sqllog(void);
233       sqlite3_init_sqllog();
234     }
235 #endif
236     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
237     sqlite3RegisterBuiltinFunctions();
238     if( sqlite3GlobalConfig.isPCacheInit==0 ){
239       rc = sqlite3PcacheInitialize();
240     }
241     if( rc==SQLITE_OK ){
242       sqlite3GlobalConfig.isPCacheInit = 1;
243       rc = sqlite3OsInit();
244     }
245 #ifdef SQLITE_ENABLE_DESERIALIZE
246     if( rc==SQLITE_OK ){
247       rc = sqlite3MemdbInit();
248     }
249 #endif
250     if( rc==SQLITE_OK ){
251       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
252           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
253       sqlite3GlobalConfig.isInit = 1;
254 #ifdef SQLITE_EXTRA_INIT
255       bRunExtraInit = 1;
256 #endif
257     }
258     sqlite3GlobalConfig.inProgress = 0;
259   }
260   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
261 
262   /* Go back under the static mutex and clean up the recursive
263   ** mutex to prevent a resource leak.
264   */
265   sqlite3_mutex_enter(pMaster);
266   sqlite3GlobalConfig.nRefInitMutex--;
267   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
268     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
269     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
270     sqlite3GlobalConfig.pInitMutex = 0;
271   }
272   sqlite3_mutex_leave(pMaster);
273 
274   /* The following is just a sanity check to make sure SQLite has
275   ** been compiled correctly.  It is important to run this code, but
276   ** we don't want to run it too often and soak up CPU cycles for no
277   ** reason.  So we run it once during initialization.
278   */
279 #ifndef NDEBUG
280 #ifndef SQLITE_OMIT_FLOATING_POINT
281   /* This section of code's only "output" is via assert() statements. */
282   if( rc==SQLITE_OK ){
283     u64 x = (((u64)1)<<63)-1;
284     double y;
285     assert(sizeof(x)==8);
286     assert(sizeof(x)==sizeof(y));
287     memcpy(&y, &x, 8);
288     assert( sqlite3IsNaN(y) );
289   }
290 #endif
291 #endif
292 
293   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
294   ** compile-time option.
295   */
296 #ifdef SQLITE_EXTRA_INIT
297   if( bRunExtraInit ){
298     int SQLITE_EXTRA_INIT(const char*);
299     rc = SQLITE_EXTRA_INIT(0);
300   }
301 #endif
302 
303   return rc;
304 }
305 
306 /*
307 ** Undo the effects of sqlite3_initialize().  Must not be called while
308 ** there are outstanding database connections or memory allocations or
309 ** while any part of SQLite is otherwise in use in any thread.  This
310 ** routine is not threadsafe.  But it is safe to invoke this routine
311 ** on when SQLite is already shut down.  If SQLite is already shut down
312 ** when this routine is invoked, then this routine is a harmless no-op.
313 */
314 int sqlite3_shutdown(void){
315 #ifdef SQLITE_OMIT_WSD
316   int rc = sqlite3_wsd_init(4096, 24);
317   if( rc!=SQLITE_OK ){
318     return rc;
319   }
320 #endif
321 
322   if( sqlite3GlobalConfig.isInit ){
323 #ifdef SQLITE_EXTRA_SHUTDOWN
324     void SQLITE_EXTRA_SHUTDOWN(void);
325     SQLITE_EXTRA_SHUTDOWN();
326 #endif
327     sqlite3_os_end();
328     sqlite3_reset_auto_extension();
329     sqlite3GlobalConfig.isInit = 0;
330   }
331   if( sqlite3GlobalConfig.isPCacheInit ){
332     sqlite3PcacheShutdown();
333     sqlite3GlobalConfig.isPCacheInit = 0;
334   }
335   if( sqlite3GlobalConfig.isMallocInit ){
336     sqlite3MallocEnd();
337     sqlite3GlobalConfig.isMallocInit = 0;
338 
339 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
340     /* The heap subsystem has now been shutdown and these values are supposed
341     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
342     ** which would rely on that heap subsystem; therefore, make sure these
343     ** values cannot refer to heap memory that was just invalidated when the
344     ** heap subsystem was shutdown.  This is only done if the current call to
345     ** this function resulted in the heap subsystem actually being shutdown.
346     */
347     sqlite3_data_directory = 0;
348     sqlite3_temp_directory = 0;
349 #endif
350   }
351   if( sqlite3GlobalConfig.isMutexInit ){
352     sqlite3MutexEnd();
353     sqlite3GlobalConfig.isMutexInit = 0;
354   }
355 
356   return SQLITE_OK;
357 }
358 
359 /*
360 ** This API allows applications to modify the global configuration of
361 ** the SQLite library at run-time.
362 **
363 ** This routine should only be called when there are no outstanding
364 ** database connections or memory allocations.  This routine is not
365 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
366 ** behavior.
367 */
368 int sqlite3_config(int op, ...){
369   va_list ap;
370   int rc = SQLITE_OK;
371 
372   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
373   ** the SQLite library is in use. */
374   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
375 
376   va_start(ap, op);
377   switch( op ){
378 
379     /* Mutex configuration options are only available in a threadsafe
380     ** compile.
381     */
382 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
383     case SQLITE_CONFIG_SINGLETHREAD: {
384       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
385       ** Single-thread. */
386       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
387       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
388       break;
389     }
390 #endif
391 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
392     case SQLITE_CONFIG_MULTITHREAD: {
393       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
394       ** Multi-thread. */
395       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
396       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
397       break;
398     }
399 #endif
400 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
401     case SQLITE_CONFIG_SERIALIZED: {
402       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
403       ** Serialized. */
404       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
405       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
406       break;
407     }
408 #endif
409 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
410     case SQLITE_CONFIG_MUTEX: {
411       /* Specify an alternative mutex implementation */
412       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
413       break;
414     }
415 #endif
416 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
417     case SQLITE_CONFIG_GETMUTEX: {
418       /* Retrieve the current mutex implementation */
419       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
420       break;
421     }
422 #endif
423 
424     case SQLITE_CONFIG_MALLOC: {
425       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
426       ** single argument which is a pointer to an instance of the
427       ** sqlite3_mem_methods structure. The argument specifies alternative
428       ** low-level memory allocation routines to be used in place of the memory
429       ** allocation routines built into SQLite. */
430       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
431       break;
432     }
433     case SQLITE_CONFIG_GETMALLOC: {
434       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
435       ** single argument which is a pointer to an instance of the
436       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
437       ** filled with the currently defined memory allocation routines. */
438       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
439       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
440       break;
441     }
442     case SQLITE_CONFIG_MEMSTATUS: {
443       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
444       ** single argument of type int, interpreted as a boolean, which enables
445       ** or disables the collection of memory allocation statistics. */
446       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
447       break;
448     }
449     case SQLITE_CONFIG_SMALL_MALLOC: {
450       sqlite3GlobalConfig.bSmallMalloc = va_arg(ap, int);
451       break;
452     }
453     case SQLITE_CONFIG_PAGECACHE: {
454       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
455       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
456       ** the size of each page cache line (sz), and the number of cache lines
457       ** (N). */
458       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
459       sqlite3GlobalConfig.szPage = va_arg(ap, int);
460       sqlite3GlobalConfig.nPage = va_arg(ap, int);
461       break;
462     }
463     case SQLITE_CONFIG_PCACHE_HDRSZ: {
464       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
465       ** a single parameter which is a pointer to an integer and writes into
466       ** that integer the number of extra bytes per page required for each page
467       ** in SQLITE_CONFIG_PAGECACHE. */
468       *va_arg(ap, int*) =
469           sqlite3HeaderSizeBtree() +
470           sqlite3HeaderSizePcache() +
471           sqlite3HeaderSizePcache1();
472       break;
473     }
474 
475     case SQLITE_CONFIG_PCACHE: {
476       /* no-op */
477       break;
478     }
479     case SQLITE_CONFIG_GETPCACHE: {
480       /* now an error */
481       rc = SQLITE_ERROR;
482       break;
483     }
484 
485     case SQLITE_CONFIG_PCACHE2: {
486       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
487       ** single argument which is a pointer to an sqlite3_pcache_methods2
488       ** object. This object specifies the interface to a custom page cache
489       ** implementation. */
490       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
491       break;
492     }
493     case SQLITE_CONFIG_GETPCACHE2: {
494       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
495       ** single argument which is a pointer to an sqlite3_pcache_methods2
496       ** object. SQLite copies of the current page cache implementation into
497       ** that object. */
498       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
499         sqlite3PCacheSetDefault();
500       }
501       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
502       break;
503     }
504 
505 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
506 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
507 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
508 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
509     case SQLITE_CONFIG_HEAP: {
510       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
511       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
512       ** number of bytes in the memory buffer, and the minimum allocation size.
513       */
514       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
515       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
516       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
517 
518       if( sqlite3GlobalConfig.mnReq<1 ){
519         sqlite3GlobalConfig.mnReq = 1;
520       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
521         /* cap min request size at 2^12 */
522         sqlite3GlobalConfig.mnReq = (1<<12);
523       }
524 
525       if( sqlite3GlobalConfig.pHeap==0 ){
526         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
527         ** is NULL, then SQLite reverts to using its default memory allocator
528         ** (the system malloc() implementation), undoing any prior invocation of
529         ** SQLITE_CONFIG_MALLOC.
530         **
531         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
532         ** revert to its default implementation when sqlite3_initialize() is run
533         */
534         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
535       }else{
536         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
537         ** alternative memory allocator is engaged to handle all of SQLites
538         ** memory allocation needs. */
539 #ifdef SQLITE_ENABLE_MEMSYS3
540         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
541 #endif
542 #ifdef SQLITE_ENABLE_MEMSYS5
543         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
544 #endif
545       }
546       break;
547     }
548 #endif
549 
550     case SQLITE_CONFIG_LOOKASIDE: {
551       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
552       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
553       break;
554     }
555 
556     /* Record a pointer to the logger function and its first argument.
557     ** The default is NULL.  Logging is disabled if the function pointer is
558     ** NULL.
559     */
560     case SQLITE_CONFIG_LOG: {
561       /* MSVC is picky about pulling func ptrs from va lists.
562       ** http://support.microsoft.com/kb/47961
563       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
564       */
565       typedef void(*LOGFUNC_t)(void*,int,const char*);
566       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
567       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
568       break;
569     }
570 
571     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
572     ** can be changed at start-time using the
573     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
574     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
575     */
576     case SQLITE_CONFIG_URI: {
577       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
578       ** argument of type int. If non-zero, then URI handling is globally
579       ** enabled. If the parameter is zero, then URI handling is globally
580       ** disabled. */
581       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
582       break;
583     }
584 
585     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
586       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
587       ** option takes a single integer argument which is interpreted as a
588       ** boolean in order to enable or disable the use of covering indices for
589       ** full table scans in the query optimizer. */
590       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
591       break;
592     }
593 
594 #ifdef SQLITE_ENABLE_SQLLOG
595     case SQLITE_CONFIG_SQLLOG: {
596       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
597       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
598       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
599       break;
600     }
601 #endif
602 
603     case SQLITE_CONFIG_MMAP_SIZE: {
604       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
605       ** integer (sqlite3_int64) values that are the default mmap size limit
606       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
607       ** mmap size limit. */
608       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
609       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
610       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
611       ** negative, then that argument is changed to its compile-time default.
612       **
613       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
614       ** silently truncated if necessary so that it does not exceed the
615       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
616       ** compile-time option.
617       */
618       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
619         mxMmap = SQLITE_MAX_MMAP_SIZE;
620       }
621       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
622       if( szMmap>mxMmap) szMmap = mxMmap;
623       sqlite3GlobalConfig.mxMmap = mxMmap;
624       sqlite3GlobalConfig.szMmap = szMmap;
625       break;
626     }
627 
628 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
629     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
630       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
631       ** unsigned integer value that specifies the maximum size of the created
632       ** heap. */
633       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
634       break;
635     }
636 #endif
637 
638     case SQLITE_CONFIG_PMASZ: {
639       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
640       break;
641     }
642 
643     case SQLITE_CONFIG_STMTJRNL_SPILL: {
644       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
645       break;
646     }
647 
648 #ifdef SQLITE_ENABLE_SORTER_REFERENCES
649     case SQLITE_CONFIG_SORTERREF_SIZE: {
650       int iVal = va_arg(ap, int);
651       if( iVal<0 ){
652         iVal = SQLITE_DEFAULT_SORTERREF_SIZE;
653       }
654       sqlite3GlobalConfig.szSorterRef = (u32)iVal;
655       break;
656     }
657 #endif /* SQLITE_ENABLE_SORTER_REFERENCES */
658 
659 #ifdef SQLITE_ENABLE_DESERIALIZE
660     case SQLITE_CONFIG_MEMDB_MAXSIZE: {
661       sqlite3GlobalConfig.mxMemdbSize = va_arg(ap, sqlite3_int64);
662       break;
663     }
664 #endif /* SQLITE_ENABLE_DESERIALIZE */
665 
666     default: {
667       rc = SQLITE_ERROR;
668       break;
669     }
670   }
671   va_end(ap);
672   return rc;
673 }
674 
675 /*
676 ** Set up the lookaside buffers for a database connection.
677 ** Return SQLITE_OK on success.
678 ** If lookaside is already active, return SQLITE_BUSY.
679 **
680 ** The sz parameter is the number of bytes in each lookaside slot.
681 ** The cnt parameter is the number of slots.  If pStart is NULL the
682 ** space for the lookaside memory is obtained from sqlite3_malloc().
683 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
684 ** the lookaside memory.
685 */
686 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
687 #ifndef SQLITE_OMIT_LOOKASIDE
688   void *pStart;
689   sqlite3_int64 szAlloc = sz*(sqlite3_int64)cnt;
690   int nBig;   /* Number of full-size slots */
691   int nSm;    /* Number smaller LOOKASIDE_SMALL-byte slots */
692 
693   if( sqlite3LookasideUsed(db,0)>0 ){
694     return SQLITE_BUSY;
695   }
696   /* Free any existing lookaside buffer for this handle before
697   ** allocating a new one so we don't have to have space for
698   ** both at the same time.
699   */
700   if( db->lookaside.bMalloced ){
701     sqlite3_free(db->lookaside.pStart);
702   }
703   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
704   ** than a pointer to be useful.
705   */
706   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
707   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
708   if( cnt<0 ) cnt = 0;
709   if( sz==0 || cnt==0 ){
710     sz = 0;
711     pStart = 0;
712   }else if( pBuf==0 ){
713     sqlite3BeginBenignMalloc();
714     pStart = sqlite3Malloc( szAlloc );  /* IMP: R-61949-35727 */
715     sqlite3EndBenignMalloc();
716     if( pStart ) szAlloc = sqlite3MallocSize(pStart);
717   }else{
718     pStart = pBuf;
719   }
720 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
721   if( sz>=LOOKASIDE_SMALL*3 ){
722     nBig = szAlloc/(3*LOOKASIDE_SMALL+sz);
723     nSm = (szAlloc - sz*nBig)/LOOKASIDE_SMALL;
724   }else if( sz>=LOOKASIDE_SMALL*2 ){
725     nBig = szAlloc/(LOOKASIDE_SMALL+sz);
726     nSm = (szAlloc - sz*nBig)/LOOKASIDE_SMALL;
727   }else
728 #endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
729   if( sz>0 ){
730     nBig = szAlloc/sz;
731     nSm = 0;
732   }else{
733     nBig = nSm = 0;
734   }
735   db->lookaside.pStart = pStart;
736   db->lookaside.pInit = 0;
737   db->lookaside.pFree = 0;
738   db->lookaside.sz = (u16)sz;
739   db->lookaside.szTrue = (u16)sz;
740   if( pStart ){
741     int i;
742     LookasideSlot *p;
743     assert( sz > (int)sizeof(LookasideSlot*) );
744     p = (LookasideSlot*)pStart;
745     for(i=0; i<nBig; i++){
746       p->pNext = db->lookaside.pInit;
747       db->lookaside.pInit = p;
748       p = (LookasideSlot*)&((u8*)p)[sz];
749     }
750 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
751     db->lookaside.pSmallInit = 0;
752     db->lookaside.pSmallFree = 0;
753     db->lookaside.pMiddle = p;
754     for(i=0; i<nSm; i++){
755       p->pNext = db->lookaside.pSmallInit;
756       db->lookaside.pSmallInit = p;
757       p = (LookasideSlot*)&((u8*)p)[LOOKASIDE_SMALL];
758     }
759 #endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
760     assert( ((uptr)p)<=szAlloc + (uptr)pStart );
761     db->lookaside.pEnd = p;
762     db->lookaside.bDisable = 0;
763     db->lookaside.bMalloced = pBuf==0 ?1:0;
764     db->lookaside.nSlot = nBig+nSm;
765   }else{
766     db->lookaside.pStart = db;
767 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
768     db->lookaside.pSmallInit = 0;
769     db->lookaside.pSmallFree = 0;
770     db->lookaside.pMiddle = db;
771 #endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
772     db->lookaside.pEnd = db;
773     db->lookaside.bDisable = 1;
774     db->lookaside.sz = 0;
775     db->lookaside.bMalloced = 0;
776     db->lookaside.nSlot = 0;
777   }
778   assert( sqlite3LookasideUsed(db,0)==0 );
779 #endif /* SQLITE_OMIT_LOOKASIDE */
780   return SQLITE_OK;
781 }
782 
783 /*
784 ** Return the mutex associated with a database connection.
785 */
786 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
787 #ifdef SQLITE_ENABLE_API_ARMOR
788   if( !sqlite3SafetyCheckOk(db) ){
789     (void)SQLITE_MISUSE_BKPT;
790     return 0;
791   }
792 #endif
793   return db->mutex;
794 }
795 
796 /*
797 ** Free up as much memory as we can from the given database
798 ** connection.
799 */
800 int sqlite3_db_release_memory(sqlite3 *db){
801   int i;
802 
803 #ifdef SQLITE_ENABLE_API_ARMOR
804   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
805 #endif
806   sqlite3_mutex_enter(db->mutex);
807   sqlite3BtreeEnterAll(db);
808   for(i=0; i<db->nDb; i++){
809     Btree *pBt = db->aDb[i].pBt;
810     if( pBt ){
811       Pager *pPager = sqlite3BtreePager(pBt);
812       sqlite3PagerShrink(pPager);
813     }
814   }
815   sqlite3BtreeLeaveAll(db);
816   sqlite3_mutex_leave(db->mutex);
817   return SQLITE_OK;
818 }
819 
820 /*
821 ** Flush any dirty pages in the pager-cache for any attached database
822 ** to disk.
823 */
824 int sqlite3_db_cacheflush(sqlite3 *db){
825   int i;
826   int rc = SQLITE_OK;
827   int bSeenBusy = 0;
828 
829 #ifdef SQLITE_ENABLE_API_ARMOR
830   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
831 #endif
832   sqlite3_mutex_enter(db->mutex);
833   sqlite3BtreeEnterAll(db);
834   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
835     Btree *pBt = db->aDb[i].pBt;
836     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
837       Pager *pPager = sqlite3BtreePager(pBt);
838       rc = sqlite3PagerFlush(pPager);
839       if( rc==SQLITE_BUSY ){
840         bSeenBusy = 1;
841         rc = SQLITE_OK;
842       }
843     }
844   }
845   sqlite3BtreeLeaveAll(db);
846   sqlite3_mutex_leave(db->mutex);
847   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
848 }
849 
850 /*
851 ** Configuration settings for an individual database connection
852 */
853 int sqlite3_db_config(sqlite3 *db, int op, ...){
854   va_list ap;
855   int rc;
856   va_start(ap, op);
857   switch( op ){
858     case SQLITE_DBCONFIG_MAINDBNAME: {
859       /* IMP: R-06824-28531 */
860       /* IMP: R-36257-52125 */
861       db->aDb[0].zDbSName = va_arg(ap,char*);
862       rc = SQLITE_OK;
863       break;
864     }
865     case SQLITE_DBCONFIG_LOOKASIDE: {
866       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
867       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
868       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
869       rc = setupLookaside(db, pBuf, sz, cnt);
870       break;
871     }
872     default: {
873       static const struct {
874         int op;      /* The opcode */
875         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
876       } aFlagOp[] = {
877         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
878         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
879         { SQLITE_DBCONFIG_ENABLE_VIEW,           SQLITE_EnableView     },
880         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
881         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
882         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
883         { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
884         { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
885         { SQLITE_DBCONFIG_RESET_DATABASE,        SQLITE_ResetDatabase  },
886         { SQLITE_DBCONFIG_DEFENSIVE,             SQLITE_Defensive      },
887         { SQLITE_DBCONFIG_WRITABLE_SCHEMA,       SQLITE_WriteSchema|
888                                                  SQLITE_NoSchemaError  },
889         { SQLITE_DBCONFIG_LEGACY_ALTER_TABLE,    SQLITE_LegacyAlter    },
890         { SQLITE_DBCONFIG_DQS_DDL,               SQLITE_DqsDDL         },
891         { SQLITE_DBCONFIG_DQS_DML,               SQLITE_DqsDML         },
892         { SQLITE_DBCONFIG_LEGACY_FILE_FORMAT,    SQLITE_LegacyFileFmt  },
893         { SQLITE_DBCONFIG_TRUSTED_SCHEMA,        SQLITE_TrustedSchema  },
894       };
895       unsigned int i;
896       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
897       for(i=0; i<ArraySize(aFlagOp); i++){
898         if( aFlagOp[i].op==op ){
899           int onoff = va_arg(ap, int);
900           int *pRes = va_arg(ap, int*);
901           u64 oldFlags = db->flags;
902           if( onoff>0 ){
903             db->flags |= aFlagOp[i].mask;
904           }else if( onoff==0 ){
905             db->flags &= ~(u64)aFlagOp[i].mask;
906           }
907           if( oldFlags!=db->flags ){
908             sqlite3ExpirePreparedStatements(db, 0);
909           }
910           if( pRes ){
911             *pRes = (db->flags & aFlagOp[i].mask)!=0;
912           }
913           rc = SQLITE_OK;
914           break;
915         }
916       }
917       break;
918     }
919   }
920   va_end(ap);
921   return rc;
922 }
923 
924 /*
925 ** This is the default collating function named "BINARY" which is always
926 ** available.
927 */
928 static int binCollFunc(
929   void *NotUsed,
930   int nKey1, const void *pKey1,
931   int nKey2, const void *pKey2
932 ){
933   int rc, n;
934   UNUSED_PARAMETER(NotUsed);
935   n = nKey1<nKey2 ? nKey1 : nKey2;
936   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
937   ** strings byte by byte using the memcmp() function from the standard C
938   ** library. */
939   assert( pKey1 && pKey2 );
940   rc = memcmp(pKey1, pKey2, n);
941   if( rc==0 ){
942     rc = nKey1 - nKey2;
943   }
944   return rc;
945 }
946 
947 /*
948 ** This is the collating function named "RTRIM" which is always
949 ** available.  Ignore trailing spaces.
950 */
951 static int rtrimCollFunc(
952   void *pUser,
953   int nKey1, const void *pKey1,
954   int nKey2, const void *pKey2
955 ){
956   const u8 *pK1 = (const u8*)pKey1;
957   const u8 *pK2 = (const u8*)pKey2;
958   while( nKey1 && pK1[nKey1-1]==' ' ) nKey1--;
959   while( nKey2 && pK2[nKey2-1]==' ' ) nKey2--;
960   return binCollFunc(pUser, nKey1, pKey1, nKey2, pKey2);
961 }
962 
963 /*
964 ** Return true if CollSeq is the default built-in BINARY.
965 */
966 int sqlite3IsBinary(const CollSeq *p){
967   assert( p==0 || p->xCmp!=binCollFunc || strcmp(p->zName,"BINARY")==0 );
968   return p==0 || p->xCmp==binCollFunc;
969 }
970 
971 /*
972 ** Another built-in collating sequence: NOCASE.
973 **
974 ** This collating sequence is intended to be used for "case independent
975 ** comparison". SQLite's knowledge of upper and lower case equivalents
976 ** extends only to the 26 characters used in the English language.
977 **
978 ** At the moment there is only a UTF-8 implementation.
979 */
980 static int nocaseCollatingFunc(
981   void *NotUsed,
982   int nKey1, const void *pKey1,
983   int nKey2, const void *pKey2
984 ){
985   int r = sqlite3StrNICmp(
986       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
987   UNUSED_PARAMETER(NotUsed);
988   if( 0==r ){
989     r = nKey1-nKey2;
990   }
991   return r;
992 }
993 
994 /*
995 ** Return the ROWID of the most recent insert
996 */
997 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
998 #ifdef SQLITE_ENABLE_API_ARMOR
999   if( !sqlite3SafetyCheckOk(db) ){
1000     (void)SQLITE_MISUSE_BKPT;
1001     return 0;
1002   }
1003 #endif
1004   return db->lastRowid;
1005 }
1006 
1007 /*
1008 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
1009 */
1010 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
1011 #ifdef SQLITE_ENABLE_API_ARMOR
1012   if( !sqlite3SafetyCheckOk(db) ){
1013     (void)SQLITE_MISUSE_BKPT;
1014     return;
1015   }
1016 #endif
1017   sqlite3_mutex_enter(db->mutex);
1018   db->lastRowid = iRowid;
1019   sqlite3_mutex_leave(db->mutex);
1020 }
1021 
1022 /*
1023 ** Return the number of changes in the most recent call to sqlite3_exec().
1024 */
1025 int sqlite3_changes(sqlite3 *db){
1026 #ifdef SQLITE_ENABLE_API_ARMOR
1027   if( !sqlite3SafetyCheckOk(db) ){
1028     (void)SQLITE_MISUSE_BKPT;
1029     return 0;
1030   }
1031 #endif
1032   return db->nChange;
1033 }
1034 
1035 /*
1036 ** Return the number of changes since the database handle was opened.
1037 */
1038 int sqlite3_total_changes(sqlite3 *db){
1039 #ifdef SQLITE_ENABLE_API_ARMOR
1040   if( !sqlite3SafetyCheckOk(db) ){
1041     (void)SQLITE_MISUSE_BKPT;
1042     return 0;
1043   }
1044 #endif
1045   return db->nTotalChange;
1046 }
1047 
1048 /*
1049 ** Close all open savepoints. This function only manipulates fields of the
1050 ** database handle object, it does not close any savepoints that may be open
1051 ** at the b-tree/pager level.
1052 */
1053 void sqlite3CloseSavepoints(sqlite3 *db){
1054   while( db->pSavepoint ){
1055     Savepoint *pTmp = db->pSavepoint;
1056     db->pSavepoint = pTmp->pNext;
1057     sqlite3DbFree(db, pTmp);
1058   }
1059   db->nSavepoint = 0;
1060   db->nStatement = 0;
1061   db->isTransactionSavepoint = 0;
1062 }
1063 
1064 /*
1065 ** Invoke the destructor function associated with FuncDef p, if any. Except,
1066 ** if this is not the last copy of the function, do not invoke it. Multiple
1067 ** copies of a single function are created when create_function() is called
1068 ** with SQLITE_ANY as the encoding.
1069 */
1070 static void functionDestroy(sqlite3 *db, FuncDef *p){
1071   FuncDestructor *pDestructor = p->u.pDestructor;
1072   if( pDestructor ){
1073     pDestructor->nRef--;
1074     if( pDestructor->nRef==0 ){
1075       pDestructor->xDestroy(pDestructor->pUserData);
1076       sqlite3DbFree(db, pDestructor);
1077     }
1078   }
1079 }
1080 
1081 /*
1082 ** Disconnect all sqlite3_vtab objects that belong to database connection
1083 ** db. This is called when db is being closed.
1084 */
1085 static void disconnectAllVtab(sqlite3 *db){
1086 #ifndef SQLITE_OMIT_VIRTUALTABLE
1087   int i;
1088   HashElem *p;
1089   sqlite3BtreeEnterAll(db);
1090   for(i=0; i<db->nDb; i++){
1091     Schema *pSchema = db->aDb[i].pSchema;
1092     if( pSchema ){
1093       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1094         Table *pTab = (Table *)sqliteHashData(p);
1095         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1096       }
1097     }
1098   }
1099   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1100     Module *pMod = (Module *)sqliteHashData(p);
1101     if( pMod->pEpoTab ){
1102       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1103     }
1104   }
1105   sqlite3VtabUnlockList(db);
1106   sqlite3BtreeLeaveAll(db);
1107 #else
1108   UNUSED_PARAMETER(db);
1109 #endif
1110 }
1111 
1112 /*
1113 ** Return TRUE if database connection db has unfinalized prepared
1114 ** statements or unfinished sqlite3_backup objects.
1115 */
1116 static int connectionIsBusy(sqlite3 *db){
1117   int j;
1118   assert( sqlite3_mutex_held(db->mutex) );
1119   if( db->pVdbe ) return 1;
1120   for(j=0; j<db->nDb; j++){
1121     Btree *pBt = db->aDb[j].pBt;
1122     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1123   }
1124   return 0;
1125 }
1126 
1127 /*
1128 ** Close an existing SQLite database
1129 */
1130 static int sqlite3Close(sqlite3 *db, int forceZombie){
1131   if( !db ){
1132     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1133     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1134     return SQLITE_OK;
1135   }
1136   if( !sqlite3SafetyCheckSickOrOk(db) ){
1137     return SQLITE_MISUSE_BKPT;
1138   }
1139   sqlite3_mutex_enter(db->mutex);
1140   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1141     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1142   }
1143 
1144   /* Force xDisconnect calls on all virtual tables */
1145   disconnectAllVtab(db);
1146 
1147   /* If a transaction is open, the disconnectAllVtab() call above
1148   ** will not have called the xDisconnect() method on any virtual
1149   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1150   ** call will do so. We need to do this before the check for active
1151   ** SQL statements below, as the v-table implementation may be storing
1152   ** some prepared statements internally.
1153   */
1154   sqlite3VtabRollback(db);
1155 
1156   /* Legacy behavior (sqlite3_close() behavior) is to return
1157   ** SQLITE_BUSY if the connection can not be closed immediately.
1158   */
1159   if( !forceZombie && connectionIsBusy(db) ){
1160     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1161        "statements or unfinished backups");
1162     sqlite3_mutex_leave(db->mutex);
1163     return SQLITE_BUSY;
1164   }
1165 
1166 #ifdef SQLITE_ENABLE_SQLLOG
1167   if( sqlite3GlobalConfig.xSqllog ){
1168     /* Closing the handle. Fourth parameter is passed the value 2. */
1169     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1170   }
1171 #endif
1172 
1173   /* Convert the connection into a zombie and then close it.
1174   */
1175   db->magic = SQLITE_MAGIC_ZOMBIE;
1176   sqlite3LeaveMutexAndCloseZombie(db);
1177   return SQLITE_OK;
1178 }
1179 
1180 /*
1181 ** Two variations on the public interface for closing a database
1182 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1183 ** leaves the connection option if there are unfinalized prepared
1184 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1185 ** version forces the connection to become a zombie if there are
1186 ** unclosed resources, and arranges for deallocation when the last
1187 ** prepare statement or sqlite3_backup closes.
1188 */
1189 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1190 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1191 
1192 
1193 /*
1194 ** Close the mutex on database connection db.
1195 **
1196 ** Furthermore, if database connection db is a zombie (meaning that there
1197 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1198 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1199 ** finished, then free all resources.
1200 */
1201 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1202   HashElem *i;                    /* Hash table iterator */
1203   int j;
1204 
1205   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1206   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1207   ** then just leave the mutex and return.
1208   */
1209   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1210     sqlite3_mutex_leave(db->mutex);
1211     return;
1212   }
1213 
1214   /* If we reach this point, it means that the database connection has
1215   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1216   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1217   ** go ahead and free all resources.
1218   */
1219 
1220   /* If a transaction is open, roll it back. This also ensures that if
1221   ** any database schemas have been modified by an uncommitted transaction
1222   ** they are reset. And that the required b-tree mutex is held to make
1223   ** the pager rollback and schema reset an atomic operation. */
1224   sqlite3RollbackAll(db, SQLITE_OK);
1225 
1226   /* Free any outstanding Savepoint structures. */
1227   sqlite3CloseSavepoints(db);
1228 
1229   /* Close all database connections */
1230   for(j=0; j<db->nDb; j++){
1231     struct Db *pDb = &db->aDb[j];
1232     if( pDb->pBt ){
1233       sqlite3BtreeClose(pDb->pBt);
1234       pDb->pBt = 0;
1235       if( j!=1 ){
1236         pDb->pSchema = 0;
1237       }
1238     }
1239   }
1240   /* Clear the TEMP schema separately and last */
1241   if( db->aDb[1].pSchema ){
1242     sqlite3SchemaClear(db->aDb[1].pSchema);
1243   }
1244   sqlite3VtabUnlockList(db);
1245 
1246   /* Free up the array of auxiliary databases */
1247   sqlite3CollapseDatabaseArray(db);
1248   assert( db->nDb<=2 );
1249   assert( db->aDb==db->aDbStatic );
1250 
1251   /* Tell the code in notify.c that the connection no longer holds any
1252   ** locks and does not require any further unlock-notify callbacks.
1253   */
1254   sqlite3ConnectionClosed(db);
1255 
1256   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1257     FuncDef *pNext, *p;
1258     p = sqliteHashData(i);
1259     do{
1260       functionDestroy(db, p);
1261       pNext = p->pNext;
1262       sqlite3DbFree(db, p);
1263       p = pNext;
1264     }while( p );
1265   }
1266   sqlite3HashClear(&db->aFunc);
1267   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1268     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1269     /* Invoke any destructors registered for collation sequence user data. */
1270     for(j=0; j<3; j++){
1271       if( pColl[j].xDel ){
1272         pColl[j].xDel(pColl[j].pUser);
1273       }
1274     }
1275     sqlite3DbFree(db, pColl);
1276   }
1277   sqlite3HashClear(&db->aCollSeq);
1278 #ifndef SQLITE_OMIT_VIRTUALTABLE
1279   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1280     Module *pMod = (Module *)sqliteHashData(i);
1281     sqlite3VtabEponymousTableClear(db, pMod);
1282     sqlite3VtabModuleUnref(db, pMod);
1283   }
1284   sqlite3HashClear(&db->aModule);
1285 #endif
1286 
1287   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1288   sqlite3ValueFree(db->pErr);
1289   sqlite3CloseExtensions(db);
1290 #if SQLITE_USER_AUTHENTICATION
1291   sqlite3_free(db->auth.zAuthUser);
1292   sqlite3_free(db->auth.zAuthPW);
1293 #endif
1294 
1295   db->magic = SQLITE_MAGIC_ERROR;
1296 
1297   /* The temp-database schema is allocated differently from the other schema
1298   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1299   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1300   ** the same sqliteMalloc() as the one that allocates the database
1301   ** structure?
1302   */
1303   sqlite3DbFree(db, db->aDb[1].pSchema);
1304   sqlite3_mutex_leave(db->mutex);
1305   db->magic = SQLITE_MAGIC_CLOSED;
1306   sqlite3_mutex_free(db->mutex);
1307   assert( sqlite3LookasideUsed(db,0)==0 );
1308   if( db->lookaside.bMalloced ){
1309     sqlite3_free(db->lookaside.pStart);
1310   }
1311   sqlite3_free(db);
1312 }
1313 
1314 /*
1315 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1316 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1317 ** breaker") and made to return tripCode if there are any further
1318 ** attempts to use that cursor.  Read cursors remain open and valid
1319 ** but are "saved" in case the table pages are moved around.
1320 */
1321 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1322   int i;
1323   int inTrans = 0;
1324   int schemaChange;
1325   assert( sqlite3_mutex_held(db->mutex) );
1326   sqlite3BeginBenignMalloc();
1327 
1328   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1329   ** This is important in case the transaction being rolled back has
1330   ** modified the database schema. If the b-tree mutexes are not taken
1331   ** here, then another shared-cache connection might sneak in between
1332   ** the database rollback and schema reset, which can cause false
1333   ** corruption reports in some cases.  */
1334   sqlite3BtreeEnterAll(db);
1335   schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
1336 
1337   for(i=0; i<db->nDb; i++){
1338     Btree *p = db->aDb[i].pBt;
1339     if( p ){
1340       if( sqlite3BtreeIsInTrans(p) ){
1341         inTrans = 1;
1342       }
1343       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1344     }
1345   }
1346   sqlite3VtabRollback(db);
1347   sqlite3EndBenignMalloc();
1348 
1349   if( schemaChange ){
1350     sqlite3ExpirePreparedStatements(db, 0);
1351     sqlite3ResetAllSchemasOfConnection(db);
1352   }
1353   sqlite3BtreeLeaveAll(db);
1354 
1355   /* Any deferred constraint violations have now been resolved. */
1356   db->nDeferredCons = 0;
1357   db->nDeferredImmCons = 0;
1358   db->flags &= ~(u64)SQLITE_DeferFKs;
1359 
1360   /* If one has been configured, invoke the rollback-hook callback */
1361   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1362     db->xRollbackCallback(db->pRollbackArg);
1363   }
1364 }
1365 
1366 /*
1367 ** Return a static string containing the name corresponding to the error code
1368 ** specified in the argument.
1369 */
1370 #if defined(SQLITE_NEED_ERR_NAME)
1371 const char *sqlite3ErrName(int rc){
1372   const char *zName = 0;
1373   int i, origRc = rc;
1374   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1375     switch( rc ){
1376       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1377       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1378       case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;
1379       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1380       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1381       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1382       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1383       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1384       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1385       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1386       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1387       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1388       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1389       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1390       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1391       case SQLITE_READONLY_CANTINIT:  zName = "SQLITE_READONLY_CANTINIT"; break;
1392       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1393       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1394       case SQLITE_READONLY_DIRECTORY: zName = "SQLITE_READONLY_DIRECTORY";break;
1395       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1396       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1397       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1398       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1399       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1400       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1401       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1402       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1403       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1404       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1405       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1406       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1407       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1408       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1409       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1410                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1411       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1412       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1413       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1414       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1415       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1416       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1417       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1418       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1419       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1420       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1421       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1422       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1423       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1424       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1425       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1426       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1427       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1428       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1429       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1430       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1431       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1432       case SQLITE_CANTOPEN_SYMLINK:   zName = "SQLITE_CANTOPEN_SYMLINK";  break;
1433       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1434       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1435       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1436       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1437       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1438       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1439       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1440       case SQLITE_CONSTRAINT_FOREIGNKEY:
1441                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1442       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1443       case SQLITE_CONSTRAINT_PRIMARYKEY:
1444                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1445       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1446       case SQLITE_CONSTRAINT_COMMITHOOK:
1447                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1448       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1449       case SQLITE_CONSTRAINT_FUNCTION:
1450                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1451       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1452       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1453       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1454       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1455       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1456       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1457       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1458       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1459       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1460       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1461       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1462       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1463                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1464       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1465       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1466       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1467     }
1468   }
1469   if( zName==0 ){
1470     static char zBuf[50];
1471     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1472     zName = zBuf;
1473   }
1474   return zName;
1475 }
1476 #endif
1477 
1478 /*
1479 ** Return a static string that describes the kind of error specified in the
1480 ** argument.
1481 */
1482 const char *sqlite3ErrStr(int rc){
1483   static const char* const aMsg[] = {
1484     /* SQLITE_OK          */ "not an error",
1485     /* SQLITE_ERROR       */ "SQL logic error",
1486     /* SQLITE_INTERNAL    */ 0,
1487     /* SQLITE_PERM        */ "access permission denied",
1488     /* SQLITE_ABORT       */ "query aborted",
1489     /* SQLITE_BUSY        */ "database is locked",
1490     /* SQLITE_LOCKED      */ "database table is locked",
1491     /* SQLITE_NOMEM       */ "out of memory",
1492     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1493     /* SQLITE_INTERRUPT   */ "interrupted",
1494     /* SQLITE_IOERR       */ "disk I/O error",
1495     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1496     /* SQLITE_NOTFOUND    */ "unknown operation",
1497     /* SQLITE_FULL        */ "database or disk is full",
1498     /* SQLITE_CANTOPEN    */ "unable to open database file",
1499     /* SQLITE_PROTOCOL    */ "locking protocol",
1500     /* SQLITE_EMPTY       */ 0,
1501     /* SQLITE_SCHEMA      */ "database schema has changed",
1502     /* SQLITE_TOOBIG      */ "string or blob too big",
1503     /* SQLITE_CONSTRAINT  */ "constraint failed",
1504     /* SQLITE_MISMATCH    */ "datatype mismatch",
1505     /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
1506 #ifdef SQLITE_DISABLE_LFS
1507     /* SQLITE_NOLFS       */ "large file support is disabled",
1508 #else
1509     /* SQLITE_NOLFS       */ 0,
1510 #endif
1511     /* SQLITE_AUTH        */ "authorization denied",
1512     /* SQLITE_FORMAT      */ 0,
1513     /* SQLITE_RANGE       */ "column index out of range",
1514     /* SQLITE_NOTADB      */ "file is not a database",
1515     /* SQLITE_NOTICE      */ "notification message",
1516     /* SQLITE_WARNING     */ "warning message",
1517   };
1518   const char *zErr = "unknown error";
1519   switch( rc ){
1520     case SQLITE_ABORT_ROLLBACK: {
1521       zErr = "abort due to ROLLBACK";
1522       break;
1523     }
1524     case SQLITE_ROW: {
1525       zErr = "another row available";
1526       break;
1527     }
1528     case SQLITE_DONE: {
1529       zErr = "no more rows available";
1530       break;
1531     }
1532     default: {
1533       rc &= 0xff;
1534       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1535         zErr = aMsg[rc];
1536       }
1537       break;
1538     }
1539   }
1540   return zErr;
1541 }
1542 
1543 /*
1544 ** This routine implements a busy callback that sleeps and tries
1545 ** again until a timeout value is reached.  The timeout value is
1546 ** an integer number of milliseconds passed in as the first
1547 ** argument.
1548 **
1549 ** Return non-zero to retry the lock.  Return zero to stop trying
1550 ** and cause SQLite to return SQLITE_BUSY.
1551 */
1552 static int sqliteDefaultBusyCallback(
1553   void *ptr,               /* Database connection */
1554   int count,               /* Number of times table has been busy */
1555   sqlite3_file *pFile      /* The file on which the lock occurred */
1556 ){
1557 #if SQLITE_OS_WIN || HAVE_USLEEP
1558   /* This case is for systems that have support for sleeping for fractions of
1559   ** a second.  Examples:  All windows systems, unix systems with usleep() */
1560   static const u8 delays[] =
1561      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1562   static const u8 totals[] =
1563      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1564 # define NDELAY ArraySize(delays)
1565   sqlite3 *db = (sqlite3 *)ptr;
1566   int tmout = db->busyTimeout;
1567   int delay, prior;
1568 
1569 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
1570   if( sqlite3OsFileControl(pFile,SQLITE_FCNTL_LOCK_TIMEOUT,&tmout)==SQLITE_OK ){
1571     if( count ){
1572       tmout = 0;
1573       sqlite3OsFileControl(pFile, SQLITE_FCNTL_LOCK_TIMEOUT, &tmout);
1574       return 0;
1575     }else{
1576       return 1;
1577     }
1578   }
1579 #else
1580   UNUSED_PARAMETER(pFile);
1581 #endif
1582   assert( count>=0 );
1583   if( count < NDELAY ){
1584     delay = delays[count];
1585     prior = totals[count];
1586   }else{
1587     delay = delays[NDELAY-1];
1588     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1589   }
1590   if( prior + delay > tmout ){
1591     delay = tmout - prior;
1592     if( delay<=0 ) return 0;
1593   }
1594   sqlite3OsSleep(db->pVfs, delay*1000);
1595   return 1;
1596 #else
1597   /* This case for unix systems that lack usleep() support.  Sleeping
1598   ** must be done in increments of whole seconds */
1599   sqlite3 *db = (sqlite3 *)ptr;
1600   int tmout = ((sqlite3 *)ptr)->busyTimeout;
1601   UNUSED_PARAMETER(pFile);
1602   if( (count+1)*1000 > tmout ){
1603     return 0;
1604   }
1605   sqlite3OsSleep(db->pVfs, 1000000);
1606   return 1;
1607 #endif
1608 }
1609 
1610 /*
1611 ** Invoke the given busy handler.
1612 **
1613 ** This routine is called when an operation failed to acquire a
1614 ** lock on VFS file pFile.
1615 **
1616 ** If this routine returns non-zero, the lock is retried.  If it
1617 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1618 */
1619 int sqlite3InvokeBusyHandler(BusyHandler *p, sqlite3_file *pFile){
1620   int rc;
1621   if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
1622   if( p->bExtraFileArg ){
1623     /* Add an extra parameter with the pFile pointer to the end of the
1624     ** callback argument list */
1625     int (*xTra)(void*,int,sqlite3_file*);
1626     xTra = (int(*)(void*,int,sqlite3_file*))p->xBusyHandler;
1627     rc = xTra(p->pBusyArg, p->nBusy, pFile);
1628   }else{
1629     /* Legacy style busy handler callback */
1630     rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
1631   }
1632   if( rc==0 ){
1633     p->nBusy = -1;
1634   }else{
1635     p->nBusy++;
1636   }
1637   return rc;
1638 }
1639 
1640 /*
1641 ** This routine sets the busy callback for an Sqlite database to the
1642 ** given callback function with the given argument.
1643 */
1644 int sqlite3_busy_handler(
1645   sqlite3 *db,
1646   int (*xBusy)(void*,int),
1647   void *pArg
1648 ){
1649 #ifdef SQLITE_ENABLE_API_ARMOR
1650   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1651 #endif
1652   sqlite3_mutex_enter(db->mutex);
1653   db->busyHandler.xBusyHandler = xBusy;
1654   db->busyHandler.pBusyArg = pArg;
1655   db->busyHandler.nBusy = 0;
1656   db->busyHandler.bExtraFileArg = 0;
1657   db->busyTimeout = 0;
1658   sqlite3_mutex_leave(db->mutex);
1659   return SQLITE_OK;
1660 }
1661 
1662 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1663 /*
1664 ** This routine sets the progress callback for an Sqlite database to the
1665 ** given callback function with the given argument. The progress callback will
1666 ** be invoked every nOps opcodes.
1667 */
1668 void sqlite3_progress_handler(
1669   sqlite3 *db,
1670   int nOps,
1671   int (*xProgress)(void*),
1672   void *pArg
1673 ){
1674 #ifdef SQLITE_ENABLE_API_ARMOR
1675   if( !sqlite3SafetyCheckOk(db) ){
1676     (void)SQLITE_MISUSE_BKPT;
1677     return;
1678   }
1679 #endif
1680   sqlite3_mutex_enter(db->mutex);
1681   if( nOps>0 ){
1682     db->xProgress = xProgress;
1683     db->nProgressOps = (unsigned)nOps;
1684     db->pProgressArg = pArg;
1685   }else{
1686     db->xProgress = 0;
1687     db->nProgressOps = 0;
1688     db->pProgressArg = 0;
1689   }
1690   sqlite3_mutex_leave(db->mutex);
1691 }
1692 #endif
1693 
1694 
1695 /*
1696 ** This routine installs a default busy handler that waits for the
1697 ** specified number of milliseconds before returning 0.
1698 */
1699 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1700 #ifdef SQLITE_ENABLE_API_ARMOR
1701   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1702 #endif
1703   if( ms>0 ){
1704     sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
1705                              (void*)db);
1706     db->busyTimeout = ms;
1707     db->busyHandler.bExtraFileArg = 1;
1708   }else{
1709     sqlite3_busy_handler(db, 0, 0);
1710   }
1711   return SQLITE_OK;
1712 }
1713 
1714 /*
1715 ** Cause any pending operation to stop at its earliest opportunity.
1716 */
1717 void sqlite3_interrupt(sqlite3 *db){
1718 #ifdef SQLITE_ENABLE_API_ARMOR
1719   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1720     (void)SQLITE_MISUSE_BKPT;
1721     return;
1722   }
1723 #endif
1724   db->u1.isInterrupted = 1;
1725 }
1726 
1727 
1728 /*
1729 ** This function is exactly the same as sqlite3_create_function(), except
1730 ** that it is designed to be called by internal code. The difference is
1731 ** that if a malloc() fails in sqlite3_create_function(), an error code
1732 ** is returned and the mallocFailed flag cleared.
1733 */
1734 int sqlite3CreateFunc(
1735   sqlite3 *db,
1736   const char *zFunctionName,
1737   int nArg,
1738   int enc,
1739   void *pUserData,
1740   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1741   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1742   void (*xFinal)(sqlite3_context*),
1743   void (*xValue)(sqlite3_context*),
1744   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1745   FuncDestructor *pDestructor
1746 ){
1747   FuncDef *p;
1748   int nName;
1749   int extraFlags;
1750 
1751   assert( sqlite3_mutex_held(db->mutex) );
1752   assert( xValue==0 || xSFunc==0 );
1753   if( zFunctionName==0                /* Must have a valid name */
1754    || (xSFunc!=0 && xFinal!=0)        /* Not both xSFunc and xFinal */
1755    || ((xFinal==0)!=(xStep==0))       /* Both or neither of xFinal and xStep */
1756    || ((xValue==0)!=(xInverse==0))    /* Both or neither of xValue, xInverse */
1757    || (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG)
1758    || (255<(nName = sqlite3Strlen30( zFunctionName)))
1759   ){
1760     return SQLITE_MISUSE_BKPT;
1761   }
1762 
1763   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1764   assert( SQLITE_FUNC_DIRECT==SQLITE_DIRECTONLY );
1765   extraFlags = enc &  (SQLITE_DETERMINISTIC|SQLITE_DIRECTONLY|
1766                        SQLITE_SUBTYPE|SQLITE_INNOCUOUS);
1767   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1768 
1769   /* The SQLITE_INNOCUOUS flag is the same bit as SQLITE_FUNC_UNSAFE.  But
1770   ** the meaning is inverted.  So flip the bit. */
1771   assert( SQLITE_FUNC_UNSAFE==SQLITE_INNOCUOUS );
1772   extraFlags ^= SQLITE_FUNC_UNSAFE;
1773 
1774 
1775 #ifndef SQLITE_OMIT_UTF16
1776   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1777   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1778   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1779   **
1780   ** If SQLITE_ANY is specified, add three versions of the function
1781   ** to the hash table.
1782   */
1783   if( enc==SQLITE_UTF16 ){
1784     enc = SQLITE_UTF16NATIVE;
1785   }else if( enc==SQLITE_ANY ){
1786     int rc;
1787     rc = sqlite3CreateFunc(db, zFunctionName, nArg,
1788          (SQLITE_UTF8|extraFlags)^SQLITE_FUNC_UNSAFE,
1789          pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1790     if( rc==SQLITE_OK ){
1791       rc = sqlite3CreateFunc(db, zFunctionName, nArg,
1792            (SQLITE_UTF16LE|extraFlags)^SQLITE_FUNC_UNSAFE,
1793            pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1794     }
1795     if( rc!=SQLITE_OK ){
1796       return rc;
1797     }
1798     enc = SQLITE_UTF16BE;
1799   }
1800 #else
1801   enc = SQLITE_UTF8;
1802 #endif
1803 
1804   /* Check if an existing function is being overridden or deleted. If so,
1805   ** and there are active VMs, then return SQLITE_BUSY. If a function
1806   ** is being overridden/deleted but there are no active VMs, allow the
1807   ** operation to continue but invalidate all precompiled statements.
1808   */
1809   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1810   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==(u32)enc && p->nArg==nArg ){
1811     if( db->nVdbeActive ){
1812       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1813         "unable to delete/modify user-function due to active statements");
1814       assert( !db->mallocFailed );
1815       return SQLITE_BUSY;
1816     }else{
1817       sqlite3ExpirePreparedStatements(db, 0);
1818     }
1819   }
1820 
1821   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1822   assert(p || db->mallocFailed);
1823   if( !p ){
1824     return SQLITE_NOMEM_BKPT;
1825   }
1826 
1827   /* If an older version of the function with a configured destructor is
1828   ** being replaced invoke the destructor function here. */
1829   functionDestroy(db, p);
1830 
1831   if( pDestructor ){
1832     pDestructor->nRef++;
1833   }
1834   p->u.pDestructor = pDestructor;
1835   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1836   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1837   testcase( p->funcFlags & SQLITE_DIRECTONLY );
1838   p->xSFunc = xSFunc ? xSFunc : xStep;
1839   p->xFinalize = xFinal;
1840   p->xValue = xValue;
1841   p->xInverse = xInverse;
1842   p->pUserData = pUserData;
1843   p->nArg = (u16)nArg;
1844   return SQLITE_OK;
1845 }
1846 
1847 /*
1848 ** Worker function used by utf-8 APIs that create new functions:
1849 **
1850 **    sqlite3_create_function()
1851 **    sqlite3_create_function_v2()
1852 **    sqlite3_create_window_function()
1853 */
1854 static int createFunctionApi(
1855   sqlite3 *db,
1856   const char *zFunc,
1857   int nArg,
1858   int enc,
1859   void *p,
1860   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1861   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1862   void (*xFinal)(sqlite3_context*),
1863   void (*xValue)(sqlite3_context*),
1864   void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
1865   void(*xDestroy)(void*)
1866 ){
1867   int rc = SQLITE_ERROR;
1868   FuncDestructor *pArg = 0;
1869 
1870 #ifdef SQLITE_ENABLE_API_ARMOR
1871   if( !sqlite3SafetyCheckOk(db) ){
1872     return SQLITE_MISUSE_BKPT;
1873   }
1874 #endif
1875   sqlite3_mutex_enter(db->mutex);
1876   if( xDestroy ){
1877     pArg = (FuncDestructor *)sqlite3Malloc(sizeof(FuncDestructor));
1878     if( !pArg ){
1879       sqlite3OomFault(db);
1880       xDestroy(p);
1881       goto out;
1882     }
1883     pArg->nRef = 0;
1884     pArg->xDestroy = xDestroy;
1885     pArg->pUserData = p;
1886   }
1887   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p,
1888       xSFunc, xStep, xFinal, xValue, xInverse, pArg
1889   );
1890   if( pArg && pArg->nRef==0 ){
1891     assert( rc!=SQLITE_OK );
1892     xDestroy(p);
1893     sqlite3_free(pArg);
1894   }
1895 
1896  out:
1897   rc = sqlite3ApiExit(db, rc);
1898   sqlite3_mutex_leave(db->mutex);
1899   return rc;
1900 }
1901 
1902 /*
1903 ** Create new user functions.
1904 */
1905 int sqlite3_create_function(
1906   sqlite3 *db,
1907   const char *zFunc,
1908   int nArg,
1909   int enc,
1910   void *p,
1911   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1912   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1913   void (*xFinal)(sqlite3_context*)
1914 ){
1915   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1916                                     xFinal, 0, 0, 0);
1917 }
1918 int sqlite3_create_function_v2(
1919   sqlite3 *db,
1920   const char *zFunc,
1921   int nArg,
1922   int enc,
1923   void *p,
1924   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1925   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1926   void (*xFinal)(sqlite3_context*),
1927   void (*xDestroy)(void *)
1928 ){
1929   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1930                                     xFinal, 0, 0, xDestroy);
1931 }
1932 int sqlite3_create_window_function(
1933   sqlite3 *db,
1934   const char *zFunc,
1935   int nArg,
1936   int enc,
1937   void *p,
1938   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1939   void (*xFinal)(sqlite3_context*),
1940   void (*xValue)(sqlite3_context*),
1941   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1942   void (*xDestroy)(void *)
1943 ){
1944   return createFunctionApi(db, zFunc, nArg, enc, p, 0, xStep,
1945                                     xFinal, xValue, xInverse, xDestroy);
1946 }
1947 
1948 #ifndef SQLITE_OMIT_UTF16
1949 int sqlite3_create_function16(
1950   sqlite3 *db,
1951   const void *zFunctionName,
1952   int nArg,
1953   int eTextRep,
1954   void *p,
1955   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1956   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1957   void (*xFinal)(sqlite3_context*)
1958 ){
1959   int rc;
1960   char *zFunc8;
1961 
1962 #ifdef SQLITE_ENABLE_API_ARMOR
1963   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1964 #endif
1965   sqlite3_mutex_enter(db->mutex);
1966   assert( !db->mallocFailed );
1967   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1968   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0,0,0);
1969   sqlite3DbFree(db, zFunc8);
1970   rc = sqlite3ApiExit(db, rc);
1971   sqlite3_mutex_leave(db->mutex);
1972   return rc;
1973 }
1974 #endif
1975 
1976 
1977 /*
1978 ** The following is the implementation of an SQL function that always
1979 ** fails with an error message stating that the function is used in the
1980 ** wrong context.  The sqlite3_overload_function() API might construct
1981 ** SQL function that use this routine so that the functions will exist
1982 ** for name resolution but are actually overloaded by the xFindFunction
1983 ** method of virtual tables.
1984 */
1985 static void sqlite3InvalidFunction(
1986   sqlite3_context *context,  /* The function calling context */
1987   int NotUsed,               /* Number of arguments to the function */
1988   sqlite3_value **NotUsed2   /* Value of each argument */
1989 ){
1990   const char *zName = (const char*)sqlite3_user_data(context);
1991   char *zErr;
1992   UNUSED_PARAMETER2(NotUsed, NotUsed2);
1993   zErr = sqlite3_mprintf(
1994       "unable to use function %s in the requested context", zName);
1995   sqlite3_result_error(context, zErr, -1);
1996   sqlite3_free(zErr);
1997 }
1998 
1999 /*
2000 ** Declare that a function has been overloaded by a virtual table.
2001 **
2002 ** If the function already exists as a regular global function, then
2003 ** this routine is a no-op.  If the function does not exist, then create
2004 ** a new one that always throws a run-time error.
2005 **
2006 ** When virtual tables intend to provide an overloaded function, they
2007 ** should call this routine to make sure the global function exists.
2008 ** A global function must exist in order for name resolution to work
2009 ** properly.
2010 */
2011 int sqlite3_overload_function(
2012   sqlite3 *db,
2013   const char *zName,
2014   int nArg
2015 ){
2016   int rc;
2017   char *zCopy;
2018 
2019 #ifdef SQLITE_ENABLE_API_ARMOR
2020   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
2021     return SQLITE_MISUSE_BKPT;
2022   }
2023 #endif
2024   sqlite3_mutex_enter(db->mutex);
2025   rc = sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)!=0;
2026   sqlite3_mutex_leave(db->mutex);
2027   if( rc ) return SQLITE_OK;
2028   zCopy = sqlite3_mprintf(zName);
2029   if( zCopy==0 ) return SQLITE_NOMEM;
2030   return sqlite3_create_function_v2(db, zName, nArg, SQLITE_UTF8,
2031                            zCopy, sqlite3InvalidFunction, 0, 0, sqlite3_free);
2032 }
2033 
2034 #ifndef SQLITE_OMIT_TRACE
2035 /*
2036 ** Register a trace function.  The pArg from the previously registered trace
2037 ** is returned.
2038 **
2039 ** A NULL trace function means that no tracing is executes.  A non-NULL
2040 ** trace is a pointer to a function that is invoked at the start of each
2041 ** SQL statement.
2042 */
2043 #ifndef SQLITE_OMIT_DEPRECATED
2044 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
2045   void *pOld;
2046 
2047 #ifdef SQLITE_ENABLE_API_ARMOR
2048   if( !sqlite3SafetyCheckOk(db) ){
2049     (void)SQLITE_MISUSE_BKPT;
2050     return 0;
2051   }
2052 #endif
2053   sqlite3_mutex_enter(db->mutex);
2054   pOld = db->pTraceArg;
2055   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
2056   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
2057   db->pTraceArg = pArg;
2058   sqlite3_mutex_leave(db->mutex);
2059   return pOld;
2060 }
2061 #endif /* SQLITE_OMIT_DEPRECATED */
2062 
2063 /* Register a trace callback using the version-2 interface.
2064 */
2065 int sqlite3_trace_v2(
2066   sqlite3 *db,                               /* Trace this connection */
2067   unsigned mTrace,                           /* Mask of events to be traced */
2068   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
2069   void *pArg                                 /* Context */
2070 ){
2071 #ifdef SQLITE_ENABLE_API_ARMOR
2072   if( !sqlite3SafetyCheckOk(db) ){
2073     return SQLITE_MISUSE_BKPT;
2074   }
2075 #endif
2076   sqlite3_mutex_enter(db->mutex);
2077   if( mTrace==0 ) xTrace = 0;
2078   if( xTrace==0 ) mTrace = 0;
2079   db->mTrace = mTrace;
2080   db->xTrace = xTrace;
2081   db->pTraceArg = pArg;
2082   sqlite3_mutex_leave(db->mutex);
2083   return SQLITE_OK;
2084 }
2085 
2086 #ifndef SQLITE_OMIT_DEPRECATED
2087 /*
2088 ** Register a profile function.  The pArg from the previously registered
2089 ** profile function is returned.
2090 **
2091 ** A NULL profile function means that no profiling is executes.  A non-NULL
2092 ** profile is a pointer to a function that is invoked at the conclusion of
2093 ** each SQL statement that is run.
2094 */
2095 void *sqlite3_profile(
2096   sqlite3 *db,
2097   void (*xProfile)(void*,const char*,sqlite_uint64),
2098   void *pArg
2099 ){
2100   void *pOld;
2101 
2102 #ifdef SQLITE_ENABLE_API_ARMOR
2103   if( !sqlite3SafetyCheckOk(db) ){
2104     (void)SQLITE_MISUSE_BKPT;
2105     return 0;
2106   }
2107 #endif
2108   sqlite3_mutex_enter(db->mutex);
2109   pOld = db->pProfileArg;
2110   db->xProfile = xProfile;
2111   db->pProfileArg = pArg;
2112   db->mTrace &= SQLITE_TRACE_NONLEGACY_MASK;
2113   if( db->xProfile ) db->mTrace |= SQLITE_TRACE_XPROFILE;
2114   sqlite3_mutex_leave(db->mutex);
2115   return pOld;
2116 }
2117 #endif /* SQLITE_OMIT_DEPRECATED */
2118 #endif /* SQLITE_OMIT_TRACE */
2119 
2120 /*
2121 ** Register a function to be invoked when a transaction commits.
2122 ** If the invoked function returns non-zero, then the commit becomes a
2123 ** rollback.
2124 */
2125 void *sqlite3_commit_hook(
2126   sqlite3 *db,              /* Attach the hook to this database */
2127   int (*xCallback)(void*),  /* Function to invoke on each commit */
2128   void *pArg                /* Argument to the function */
2129 ){
2130   void *pOld;
2131 
2132 #ifdef SQLITE_ENABLE_API_ARMOR
2133   if( !sqlite3SafetyCheckOk(db) ){
2134     (void)SQLITE_MISUSE_BKPT;
2135     return 0;
2136   }
2137 #endif
2138   sqlite3_mutex_enter(db->mutex);
2139   pOld = db->pCommitArg;
2140   db->xCommitCallback = xCallback;
2141   db->pCommitArg = pArg;
2142   sqlite3_mutex_leave(db->mutex);
2143   return pOld;
2144 }
2145 
2146 /*
2147 ** Register a callback to be invoked each time a row is updated,
2148 ** inserted or deleted using this database connection.
2149 */
2150 void *sqlite3_update_hook(
2151   sqlite3 *db,              /* Attach the hook to this database */
2152   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
2153   void *pArg                /* Argument to the function */
2154 ){
2155   void *pRet;
2156 
2157 #ifdef SQLITE_ENABLE_API_ARMOR
2158   if( !sqlite3SafetyCheckOk(db) ){
2159     (void)SQLITE_MISUSE_BKPT;
2160     return 0;
2161   }
2162 #endif
2163   sqlite3_mutex_enter(db->mutex);
2164   pRet = db->pUpdateArg;
2165   db->xUpdateCallback = xCallback;
2166   db->pUpdateArg = pArg;
2167   sqlite3_mutex_leave(db->mutex);
2168   return pRet;
2169 }
2170 
2171 /*
2172 ** Register a callback to be invoked each time a transaction is rolled
2173 ** back by this database connection.
2174 */
2175 void *sqlite3_rollback_hook(
2176   sqlite3 *db,              /* Attach the hook to this database */
2177   void (*xCallback)(void*), /* Callback function */
2178   void *pArg                /* Argument to the function */
2179 ){
2180   void *pRet;
2181 
2182 #ifdef SQLITE_ENABLE_API_ARMOR
2183   if( !sqlite3SafetyCheckOk(db) ){
2184     (void)SQLITE_MISUSE_BKPT;
2185     return 0;
2186   }
2187 #endif
2188   sqlite3_mutex_enter(db->mutex);
2189   pRet = db->pRollbackArg;
2190   db->xRollbackCallback = xCallback;
2191   db->pRollbackArg = pArg;
2192   sqlite3_mutex_leave(db->mutex);
2193   return pRet;
2194 }
2195 
2196 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2197 /*
2198 ** Register a callback to be invoked each time a row is updated,
2199 ** inserted or deleted using this database connection.
2200 */
2201 void *sqlite3_preupdate_hook(
2202   sqlite3 *db,              /* Attach the hook to this database */
2203   void(*xCallback)(         /* Callback function */
2204     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
2205   void *pArg                /* First callback argument */
2206 ){
2207   void *pRet;
2208   sqlite3_mutex_enter(db->mutex);
2209   pRet = db->pPreUpdateArg;
2210   db->xPreUpdateCallback = xCallback;
2211   db->pPreUpdateArg = pArg;
2212   sqlite3_mutex_leave(db->mutex);
2213   return pRet;
2214 }
2215 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2216 
2217 #ifndef SQLITE_OMIT_WAL
2218 /*
2219 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2220 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2221 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2222 ** wal_autocheckpoint()).
2223 */
2224 int sqlite3WalDefaultHook(
2225   void *pClientData,     /* Argument */
2226   sqlite3 *db,           /* Connection */
2227   const char *zDb,       /* Database */
2228   int nFrame             /* Size of WAL */
2229 ){
2230   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2231     sqlite3BeginBenignMalloc();
2232     sqlite3_wal_checkpoint(db, zDb);
2233     sqlite3EndBenignMalloc();
2234   }
2235   return SQLITE_OK;
2236 }
2237 #endif /* SQLITE_OMIT_WAL */
2238 
2239 /*
2240 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2241 ** a database after committing a transaction if there are nFrame or
2242 ** more frames in the log file. Passing zero or a negative value as the
2243 ** nFrame parameter disables automatic checkpoints entirely.
2244 **
2245 ** The callback registered by this function replaces any existing callback
2246 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2247 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2248 ** configured by this function.
2249 */
2250 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2251 #ifdef SQLITE_OMIT_WAL
2252   UNUSED_PARAMETER(db);
2253   UNUSED_PARAMETER(nFrame);
2254 #else
2255 #ifdef SQLITE_ENABLE_API_ARMOR
2256   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2257 #endif
2258   if( nFrame>0 ){
2259     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2260   }else{
2261     sqlite3_wal_hook(db, 0, 0);
2262   }
2263 #endif
2264   return SQLITE_OK;
2265 }
2266 
2267 /*
2268 ** Register a callback to be invoked each time a transaction is written
2269 ** into the write-ahead-log by this database connection.
2270 */
2271 void *sqlite3_wal_hook(
2272   sqlite3 *db,                    /* Attach the hook to this db handle */
2273   int(*xCallback)(void *, sqlite3*, const char*, int),
2274   void *pArg                      /* First argument passed to xCallback() */
2275 ){
2276 #ifndef SQLITE_OMIT_WAL
2277   void *pRet;
2278 #ifdef SQLITE_ENABLE_API_ARMOR
2279   if( !sqlite3SafetyCheckOk(db) ){
2280     (void)SQLITE_MISUSE_BKPT;
2281     return 0;
2282   }
2283 #endif
2284   sqlite3_mutex_enter(db->mutex);
2285   pRet = db->pWalArg;
2286   db->xWalCallback = xCallback;
2287   db->pWalArg = pArg;
2288   sqlite3_mutex_leave(db->mutex);
2289   return pRet;
2290 #else
2291   return 0;
2292 #endif
2293 }
2294 
2295 /*
2296 ** Checkpoint database zDb.
2297 */
2298 int sqlite3_wal_checkpoint_v2(
2299   sqlite3 *db,                    /* Database handle */
2300   const char *zDb,                /* Name of attached database (or NULL) */
2301   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2302   int *pnLog,                     /* OUT: Size of WAL log in frames */
2303   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2304 ){
2305 #ifdef SQLITE_OMIT_WAL
2306   return SQLITE_OK;
2307 #else
2308   int rc;                         /* Return code */
2309   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2310 
2311 #ifdef SQLITE_ENABLE_API_ARMOR
2312   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2313 #endif
2314 
2315   /* Initialize the output variables to -1 in case an error occurs. */
2316   if( pnLog ) *pnLog = -1;
2317   if( pnCkpt ) *pnCkpt = -1;
2318 
2319   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2320   assert( SQLITE_CHECKPOINT_FULL==1 );
2321   assert( SQLITE_CHECKPOINT_RESTART==2 );
2322   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2323   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2324     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2325     ** mode: */
2326     return SQLITE_MISUSE;
2327   }
2328 
2329   sqlite3_mutex_enter(db->mutex);
2330   if( zDb && zDb[0] ){
2331     iDb = sqlite3FindDbName(db, zDb);
2332   }
2333   if( iDb<0 ){
2334     rc = SQLITE_ERROR;
2335     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2336   }else{
2337     db->busyHandler.nBusy = 0;
2338     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2339     sqlite3Error(db, rc);
2340   }
2341   rc = sqlite3ApiExit(db, rc);
2342 
2343   /* If there are no active statements, clear the interrupt flag at this
2344   ** point.  */
2345   if( db->nVdbeActive==0 ){
2346     db->u1.isInterrupted = 0;
2347   }
2348 
2349   sqlite3_mutex_leave(db->mutex);
2350   return rc;
2351 #endif
2352 }
2353 
2354 
2355 /*
2356 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2357 ** to contains a zero-length string, all attached databases are
2358 ** checkpointed.
2359 */
2360 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2361   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2362   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2363   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2364 }
2365 
2366 #ifndef SQLITE_OMIT_WAL
2367 /*
2368 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2369 ** not currently open in WAL mode.
2370 **
2371 ** If a transaction is open on the database being checkpointed, this
2372 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2373 ** an error occurs while running the checkpoint, an SQLite error code is
2374 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2375 **
2376 ** The mutex on database handle db should be held by the caller. The mutex
2377 ** associated with the specific b-tree being checkpointed is taken by
2378 ** this function while the checkpoint is running.
2379 **
2380 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2381 ** checkpointed. If an error is encountered it is returned immediately -
2382 ** no attempt is made to checkpoint any remaining databases.
2383 **
2384 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
2385 ** or TRUNCATE.
2386 */
2387 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2388   int rc = SQLITE_OK;             /* Return code */
2389   int i;                          /* Used to iterate through attached dbs */
2390   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2391 
2392   assert( sqlite3_mutex_held(db->mutex) );
2393   assert( !pnLog || *pnLog==-1 );
2394   assert( !pnCkpt || *pnCkpt==-1 );
2395 
2396   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2397     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2398       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2399       pnLog = 0;
2400       pnCkpt = 0;
2401       if( rc==SQLITE_BUSY ){
2402         bBusy = 1;
2403         rc = SQLITE_OK;
2404       }
2405     }
2406   }
2407 
2408   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2409 }
2410 #endif /* SQLITE_OMIT_WAL */
2411 
2412 /*
2413 ** This function returns true if main-memory should be used instead of
2414 ** a temporary file for transient pager files and statement journals.
2415 ** The value returned depends on the value of db->temp_store (runtime
2416 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2417 ** following table describes the relationship between these two values
2418 ** and this functions return value.
2419 **
2420 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2421 **   -----------------     --------------     ------------------------------
2422 **   0                     any                file      (return 0)
2423 **   1                     1                  file      (return 0)
2424 **   1                     2                  memory    (return 1)
2425 **   1                     0                  file      (return 0)
2426 **   2                     1                  file      (return 0)
2427 **   2                     2                  memory    (return 1)
2428 **   2                     0                  memory    (return 1)
2429 **   3                     any                memory    (return 1)
2430 */
2431 int sqlite3TempInMemory(const sqlite3 *db){
2432 #if SQLITE_TEMP_STORE==1
2433   return ( db->temp_store==2 );
2434 #endif
2435 #if SQLITE_TEMP_STORE==2
2436   return ( db->temp_store!=1 );
2437 #endif
2438 #if SQLITE_TEMP_STORE==3
2439   UNUSED_PARAMETER(db);
2440   return 1;
2441 #endif
2442 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2443   UNUSED_PARAMETER(db);
2444   return 0;
2445 #endif
2446 }
2447 
2448 /*
2449 ** Return UTF-8 encoded English language explanation of the most recent
2450 ** error.
2451 */
2452 const char *sqlite3_errmsg(sqlite3 *db){
2453   const char *z;
2454   if( !db ){
2455     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2456   }
2457   if( !sqlite3SafetyCheckSickOrOk(db) ){
2458     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2459   }
2460   sqlite3_mutex_enter(db->mutex);
2461   if( db->mallocFailed ){
2462     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2463   }else{
2464     testcase( db->pErr==0 );
2465     z = db->errCode ? (char*)sqlite3_value_text(db->pErr) : 0;
2466     assert( !db->mallocFailed );
2467     if( z==0 ){
2468       z = sqlite3ErrStr(db->errCode);
2469     }
2470   }
2471   sqlite3_mutex_leave(db->mutex);
2472   return z;
2473 }
2474 
2475 #ifndef SQLITE_OMIT_UTF16
2476 /*
2477 ** Return UTF-16 encoded English language explanation of the most recent
2478 ** error.
2479 */
2480 const void *sqlite3_errmsg16(sqlite3 *db){
2481   static const u16 outOfMem[] = {
2482     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2483   };
2484   static const u16 misuse[] = {
2485     'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
2486     'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
2487     'm', 'i', 's', 'u', 's', 'e', 0
2488   };
2489 
2490   const void *z;
2491   if( !db ){
2492     return (void *)outOfMem;
2493   }
2494   if( !sqlite3SafetyCheckSickOrOk(db) ){
2495     return (void *)misuse;
2496   }
2497   sqlite3_mutex_enter(db->mutex);
2498   if( db->mallocFailed ){
2499     z = (void *)outOfMem;
2500   }else{
2501     z = sqlite3_value_text16(db->pErr);
2502     if( z==0 ){
2503       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2504       z = sqlite3_value_text16(db->pErr);
2505     }
2506     /* A malloc() may have failed within the call to sqlite3_value_text16()
2507     ** above. If this is the case, then the db->mallocFailed flag needs to
2508     ** be cleared before returning. Do this directly, instead of via
2509     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2510     */
2511     sqlite3OomClear(db);
2512   }
2513   sqlite3_mutex_leave(db->mutex);
2514   return z;
2515 }
2516 #endif /* SQLITE_OMIT_UTF16 */
2517 
2518 /*
2519 ** Return the most recent error code generated by an SQLite routine. If NULL is
2520 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2521 */
2522 int sqlite3_errcode(sqlite3 *db){
2523   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2524     return SQLITE_MISUSE_BKPT;
2525   }
2526   if( !db || db->mallocFailed ){
2527     return SQLITE_NOMEM_BKPT;
2528   }
2529   return db->errCode & db->errMask;
2530 }
2531 int sqlite3_extended_errcode(sqlite3 *db){
2532   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2533     return SQLITE_MISUSE_BKPT;
2534   }
2535   if( !db || db->mallocFailed ){
2536     return SQLITE_NOMEM_BKPT;
2537   }
2538   return db->errCode;
2539 }
2540 int sqlite3_system_errno(sqlite3 *db){
2541   return db ? db->iSysErrno : 0;
2542 }
2543 
2544 /*
2545 ** Return a string that describes the kind of error specified in the
2546 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2547 ** function.
2548 */
2549 const char *sqlite3_errstr(int rc){
2550   return sqlite3ErrStr(rc);
2551 }
2552 
2553 /*
2554 ** Create a new collating function for database "db".  The name is zName
2555 ** and the encoding is enc.
2556 */
2557 static int createCollation(
2558   sqlite3* db,
2559   const char *zName,
2560   u8 enc,
2561   void* pCtx,
2562   int(*xCompare)(void*,int,const void*,int,const void*),
2563   void(*xDel)(void*)
2564 ){
2565   CollSeq *pColl;
2566   int enc2;
2567 
2568   assert( sqlite3_mutex_held(db->mutex) );
2569 
2570   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2571   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2572   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2573   */
2574   enc2 = enc;
2575   testcase( enc2==SQLITE_UTF16 );
2576   testcase( enc2==SQLITE_UTF16_ALIGNED );
2577   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2578     enc2 = SQLITE_UTF16NATIVE;
2579   }
2580   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2581     return SQLITE_MISUSE_BKPT;
2582   }
2583 
2584   /* Check if this call is removing or replacing an existing collation
2585   ** sequence. If so, and there are active VMs, return busy. If there
2586   ** are no active VMs, invalidate any pre-compiled statements.
2587   */
2588   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2589   if( pColl && pColl->xCmp ){
2590     if( db->nVdbeActive ){
2591       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2592         "unable to delete/modify collation sequence due to active statements");
2593       return SQLITE_BUSY;
2594     }
2595     sqlite3ExpirePreparedStatements(db, 0);
2596 
2597     /* If collation sequence pColl was created directly by a call to
2598     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2599     ** then any copies made by synthCollSeq() need to be invalidated.
2600     ** Also, collation destructor - CollSeq.xDel() - function may need
2601     ** to be called.
2602     */
2603     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2604       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2605       int j;
2606       for(j=0; j<3; j++){
2607         CollSeq *p = &aColl[j];
2608         if( p->enc==pColl->enc ){
2609           if( p->xDel ){
2610             p->xDel(p->pUser);
2611           }
2612           p->xCmp = 0;
2613         }
2614       }
2615     }
2616   }
2617 
2618   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2619   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2620   pColl->xCmp = xCompare;
2621   pColl->pUser = pCtx;
2622   pColl->xDel = xDel;
2623   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2624   sqlite3Error(db, SQLITE_OK);
2625   return SQLITE_OK;
2626 }
2627 
2628 
2629 /*
2630 ** This array defines hard upper bounds on limit values.  The
2631 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2632 ** #defines in sqlite3.h.
2633 */
2634 static const int aHardLimit[] = {
2635   SQLITE_MAX_LENGTH,
2636   SQLITE_MAX_SQL_LENGTH,
2637   SQLITE_MAX_COLUMN,
2638   SQLITE_MAX_EXPR_DEPTH,
2639   SQLITE_MAX_COMPOUND_SELECT,
2640   SQLITE_MAX_VDBE_OP,
2641   SQLITE_MAX_FUNCTION_ARG,
2642   SQLITE_MAX_ATTACHED,
2643   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2644   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2645   SQLITE_MAX_TRIGGER_DEPTH,
2646   SQLITE_MAX_WORKER_THREADS,
2647 };
2648 
2649 /*
2650 ** Make sure the hard limits are set to reasonable values
2651 */
2652 #if SQLITE_MAX_LENGTH<100
2653 # error SQLITE_MAX_LENGTH must be at least 100
2654 #endif
2655 #if SQLITE_MAX_SQL_LENGTH<100
2656 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2657 #endif
2658 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2659 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2660 #endif
2661 #if SQLITE_MAX_COMPOUND_SELECT<2
2662 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2663 #endif
2664 #if SQLITE_MAX_VDBE_OP<40
2665 # error SQLITE_MAX_VDBE_OP must be at least 40
2666 #endif
2667 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2668 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2669 #endif
2670 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2671 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2672 #endif
2673 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2674 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2675 #endif
2676 #if SQLITE_MAX_COLUMN>32767
2677 # error SQLITE_MAX_COLUMN must not exceed 32767
2678 #endif
2679 #if SQLITE_MAX_TRIGGER_DEPTH<1
2680 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2681 #endif
2682 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2683 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2684 #endif
2685 
2686 
2687 /*
2688 ** Change the value of a limit.  Report the old value.
2689 ** If an invalid limit index is supplied, report -1.
2690 ** Make no changes but still report the old value if the
2691 ** new limit is negative.
2692 **
2693 ** A new lower limit does not shrink existing constructs.
2694 ** It merely prevents new constructs that exceed the limit
2695 ** from forming.
2696 */
2697 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2698   int oldLimit;
2699 
2700 #ifdef SQLITE_ENABLE_API_ARMOR
2701   if( !sqlite3SafetyCheckOk(db) ){
2702     (void)SQLITE_MISUSE_BKPT;
2703     return -1;
2704   }
2705 #endif
2706 
2707   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2708   ** there is a hard upper bound set at compile-time by a C preprocessor
2709   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2710   ** "_MAX_".)
2711   */
2712   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2713   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2714   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2715   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2716   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2717   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2718   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2719   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2720   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2721                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2722   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2723   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2724   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2725   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2726 
2727 
2728   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2729     return -1;
2730   }
2731   oldLimit = db->aLimit[limitId];
2732   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2733     if( newLimit>aHardLimit[limitId] ){
2734       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2735     }
2736     db->aLimit[limitId] = newLimit;
2737   }
2738   return oldLimit;                     /* IMP: R-53341-35419 */
2739 }
2740 
2741 /*
2742 ** This function is used to parse both URIs and non-URI filenames passed by the
2743 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2744 ** URIs specified as part of ATTACH statements.
2745 **
2746 ** The first argument to this function is the name of the VFS to use (or
2747 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2748 ** query parameter. The second argument contains the URI (or non-URI filename)
2749 ** itself. When this function is called the *pFlags variable should contain
2750 ** the default flags to open the database handle with. The value stored in
2751 ** *pFlags may be updated before returning if the URI filename contains
2752 ** "cache=xxx" or "mode=xxx" query parameters.
2753 **
2754 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2755 ** the VFS that should be used to open the database file. *pzFile is set to
2756 ** point to a buffer containing the name of the file to open.  The value
2757 ** stored in *pzFile is a database name acceptable to sqlite3_uri_parameter()
2758 ** and is in the same format as names created using sqlite3_create_filename().
2759 ** The caller must invoke sqlite3_free_filename() (not sqlite3_free()!) on
2760 ** the value returned in *pzFile to avoid a memory leak.
2761 **
2762 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2763 ** may be set to point to a buffer containing an English language error
2764 ** message. It is the responsibility of the caller to eventually release
2765 ** this buffer by calling sqlite3_free().
2766 */
2767 int sqlite3ParseUri(
2768   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2769   const char *zUri,               /* Nul-terminated URI to parse */
2770   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2771   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2772   char **pzFile,                  /* OUT: Filename component of URI */
2773   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2774 ){
2775   int rc = SQLITE_OK;
2776   unsigned int flags = *pFlags;
2777   const char *zVfs = zDefaultVfs;
2778   char *zFile;
2779   char c;
2780   int nUri = sqlite3Strlen30(zUri);
2781 
2782   assert( *pzErrMsg==0 );
2783 
2784   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2785             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2786    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2787   ){
2788     char *zOpt;
2789     int eState;                   /* Parser state when parsing URI */
2790     int iIn;                      /* Input character index */
2791     int iOut = 0;                 /* Output character index */
2792     u64 nByte = nUri+8;           /* Bytes of space to allocate */
2793 
2794     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2795     ** method that there may be extra parameters following the file-name.  */
2796     flags |= SQLITE_OPEN_URI;
2797 
2798     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2799     zFile = sqlite3_malloc64(nByte);
2800     if( !zFile ) return SQLITE_NOMEM_BKPT;
2801 
2802     memset(zFile, 0, 4);  /* 4-byte of 0x00 is the start of DB name marker */
2803     zFile += 4;
2804 
2805     iIn = 5;
2806 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2807     if( strncmp(zUri+5, "///", 3)==0 ){
2808       iIn = 7;
2809       /* The following condition causes URIs with five leading / characters
2810       ** like file://///host/path to be converted into UNCs like //host/path.
2811       ** The correct URI for that UNC has only two or four leading / characters
2812       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2813       ** common error, we are told, so we handle it as a special case. */
2814       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2815     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2816       iIn = 16;
2817     }
2818 #else
2819     /* Discard the scheme and authority segments of the URI. */
2820     if( zUri[5]=='/' && zUri[6]=='/' ){
2821       iIn = 7;
2822       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2823       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2824         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2825             iIn-7, &zUri[7]);
2826         rc = SQLITE_ERROR;
2827         goto parse_uri_out;
2828       }
2829     }
2830 #endif
2831 
2832     /* Copy the filename and any query parameters into the zFile buffer.
2833     ** Decode %HH escape codes along the way.
2834     **
2835     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2836     ** on the parsing context. As follows:
2837     **
2838     **   0: Parsing file-name.
2839     **   1: Parsing name section of a name=value query parameter.
2840     **   2: Parsing value section of a name=value query parameter.
2841     */
2842     eState = 0;
2843     while( (c = zUri[iIn])!=0 && c!='#' ){
2844       iIn++;
2845       if( c=='%'
2846        && sqlite3Isxdigit(zUri[iIn])
2847        && sqlite3Isxdigit(zUri[iIn+1])
2848       ){
2849         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2850         octet += sqlite3HexToInt(zUri[iIn++]);
2851 
2852         assert( octet>=0 && octet<256 );
2853         if( octet==0 ){
2854 #ifndef SQLITE_ENABLE_URI_00_ERROR
2855           /* This branch is taken when "%00" appears within the URI. In this
2856           ** case we ignore all text in the remainder of the path, name or
2857           ** value currently being parsed. So ignore the current character
2858           ** and skip to the next "?", "=" or "&", as appropriate. */
2859           while( (c = zUri[iIn])!=0 && c!='#'
2860               && (eState!=0 || c!='?')
2861               && (eState!=1 || (c!='=' && c!='&'))
2862               && (eState!=2 || c!='&')
2863           ){
2864             iIn++;
2865           }
2866           continue;
2867 #else
2868           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2869           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2870           rc = SQLITE_ERROR;
2871           goto parse_uri_out;
2872 #endif
2873         }
2874         c = octet;
2875       }else if( eState==1 && (c=='&' || c=='=') ){
2876         if( zFile[iOut-1]==0 ){
2877           /* An empty option name. Ignore this option altogether. */
2878           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2879           continue;
2880         }
2881         if( c=='&' ){
2882           zFile[iOut++] = '\0';
2883         }else{
2884           eState = 2;
2885         }
2886         c = 0;
2887       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2888         c = 0;
2889         eState = 1;
2890       }
2891       zFile[iOut++] = c;
2892     }
2893     if( eState==1 ) zFile[iOut++] = '\0';
2894     memset(zFile+iOut, 0, 4); /* end-of-options + empty journal filenames */
2895 
2896     /* Check if there were any options specified that should be interpreted
2897     ** here. Options that are interpreted here include "vfs" and those that
2898     ** correspond to flags that may be passed to the sqlite3_open_v2()
2899     ** method. */
2900     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2901     while( zOpt[0] ){
2902       int nOpt = sqlite3Strlen30(zOpt);
2903       char *zVal = &zOpt[nOpt+1];
2904       int nVal = sqlite3Strlen30(zVal);
2905 
2906       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2907         zVfs = zVal;
2908       }else{
2909         struct OpenMode {
2910           const char *z;
2911           int mode;
2912         } *aMode = 0;
2913         char *zModeType = 0;
2914         int mask = 0;
2915         int limit = 0;
2916 
2917         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2918           static struct OpenMode aCacheMode[] = {
2919             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2920             { "private", SQLITE_OPEN_PRIVATECACHE },
2921             { 0, 0 }
2922           };
2923 
2924           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2925           aMode = aCacheMode;
2926           limit = mask;
2927           zModeType = "cache";
2928         }
2929         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2930           static struct OpenMode aOpenMode[] = {
2931             { "ro",  SQLITE_OPEN_READONLY },
2932             { "rw",  SQLITE_OPEN_READWRITE },
2933             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2934             { "memory", SQLITE_OPEN_MEMORY },
2935             { 0, 0 }
2936           };
2937 
2938           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2939                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2940           aMode = aOpenMode;
2941           limit = mask & flags;
2942           zModeType = "access";
2943         }
2944 
2945         if( aMode ){
2946           int i;
2947           int mode = 0;
2948           for(i=0; aMode[i].z; i++){
2949             const char *z = aMode[i].z;
2950             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2951               mode = aMode[i].mode;
2952               break;
2953             }
2954           }
2955           if( mode==0 ){
2956             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2957             rc = SQLITE_ERROR;
2958             goto parse_uri_out;
2959           }
2960           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2961             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2962                                         zModeType, zVal);
2963             rc = SQLITE_PERM;
2964             goto parse_uri_out;
2965           }
2966           flags = (flags & ~mask) | mode;
2967         }
2968       }
2969 
2970       zOpt = &zVal[nVal+1];
2971     }
2972 
2973   }else{
2974     zFile = sqlite3_malloc64(nUri+8);
2975     if( !zFile ) return SQLITE_NOMEM_BKPT;
2976     memset(zFile, 0, 4);
2977     zFile += 4;
2978     if( nUri ){
2979       memcpy(zFile, zUri, nUri);
2980     }
2981     memset(zFile+nUri, 0, 4);
2982     flags &= ~SQLITE_OPEN_URI;
2983   }
2984 
2985   *ppVfs = sqlite3_vfs_find(zVfs);
2986   if( *ppVfs==0 ){
2987     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2988     rc = SQLITE_ERROR;
2989   }
2990  parse_uri_out:
2991   if( rc!=SQLITE_OK ){
2992     sqlite3_free_filename(zFile);
2993     zFile = 0;
2994   }
2995   *pFlags = flags;
2996   *pzFile = zFile;
2997   return rc;
2998 }
2999 
3000 /*
3001 ** This routine does the core work of extracting URI parameters from a
3002 ** database filename for the sqlite3_uri_parameter() interface.
3003 */
3004 static const char *uriParameter(const char *zFilename, const char *zParam){
3005   zFilename += sqlite3Strlen30(zFilename) + 1;
3006   while( zFilename[0] ){
3007     int x = strcmp(zFilename, zParam);
3008     zFilename += sqlite3Strlen30(zFilename) + 1;
3009     if( x==0 ) return zFilename;
3010     zFilename += sqlite3Strlen30(zFilename) + 1;
3011   }
3012   return 0;
3013 }
3014 
3015 
3016 
3017 /*
3018 ** This routine does the work of opening a database on behalf of
3019 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
3020 ** is UTF-8 encoded.
3021 */
3022 static int openDatabase(
3023   const char *zFilename, /* Database filename UTF-8 encoded */
3024   sqlite3 **ppDb,        /* OUT: Returned database handle */
3025   unsigned int flags,    /* Operational flags */
3026   const char *zVfs       /* Name of the VFS to use */
3027 ){
3028   sqlite3 *db;                    /* Store allocated handle here */
3029   int rc;                         /* Return code */
3030   int isThreadsafe;               /* True for threadsafe connections */
3031   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
3032   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
3033 
3034 #ifdef SQLITE_ENABLE_API_ARMOR
3035   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3036 #endif
3037   *ppDb = 0;
3038 #ifndef SQLITE_OMIT_AUTOINIT
3039   rc = sqlite3_initialize();
3040   if( rc ) return rc;
3041 #endif
3042 
3043   if( sqlite3GlobalConfig.bCoreMutex==0 ){
3044     isThreadsafe = 0;
3045   }else if( flags & SQLITE_OPEN_NOMUTEX ){
3046     isThreadsafe = 0;
3047   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
3048     isThreadsafe = 1;
3049   }else{
3050     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
3051   }
3052 
3053   if( flags & SQLITE_OPEN_PRIVATECACHE ){
3054     flags &= ~SQLITE_OPEN_SHAREDCACHE;
3055   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
3056     flags |= SQLITE_OPEN_SHAREDCACHE;
3057   }
3058 
3059   /* Remove harmful bits from the flags parameter
3060   **
3061   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
3062   ** dealt with in the previous code block.  Besides these, the only
3063   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
3064   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
3065   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
3066   ** off all other flags.
3067   */
3068   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
3069                SQLITE_OPEN_EXCLUSIVE |
3070                SQLITE_OPEN_MAIN_DB |
3071                SQLITE_OPEN_TEMP_DB |
3072                SQLITE_OPEN_TRANSIENT_DB |
3073                SQLITE_OPEN_MAIN_JOURNAL |
3074                SQLITE_OPEN_TEMP_JOURNAL |
3075                SQLITE_OPEN_SUBJOURNAL |
3076                SQLITE_OPEN_MASTER_JOURNAL |
3077                SQLITE_OPEN_NOMUTEX |
3078                SQLITE_OPEN_FULLMUTEX |
3079                SQLITE_OPEN_WAL
3080              );
3081 
3082   /* Allocate the sqlite data structure */
3083   db = sqlite3MallocZero( sizeof(sqlite3) );
3084   if( db==0 ) goto opendb_out;
3085   if( isThreadsafe
3086 #ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
3087    || sqlite3GlobalConfig.bCoreMutex
3088 #endif
3089   ){
3090     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
3091     if( db->mutex==0 ){
3092       sqlite3_free(db);
3093       db = 0;
3094       goto opendb_out;
3095     }
3096     if( isThreadsafe==0 ){
3097       sqlite3MutexWarnOnContention(db->mutex);
3098     }
3099   }
3100   sqlite3_mutex_enter(db->mutex);
3101   db->errMask = 0xff;
3102   db->nDb = 2;
3103   db->magic = SQLITE_MAGIC_BUSY;
3104   db->aDb = db->aDbStatic;
3105   db->lookaside.bDisable = 1;
3106   db->lookaside.sz = 0;
3107 
3108   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
3109   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
3110   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
3111   db->autoCommit = 1;
3112   db->nextAutovac = -1;
3113   db->szMmap = sqlite3GlobalConfig.szMmap;
3114   db->nextPagesize = 0;
3115   db->nMaxSorterMmap = 0x7FFFFFFF;
3116   db->flags |= SQLITE_ShortColNames
3117                  | SQLITE_EnableTrigger
3118                  | SQLITE_EnableView
3119                  | SQLITE_CacheSpill
3120 #if !defined(SQLITE_TRUSTED_SCHEMA) || SQLITE_TRUSTED_SCHEMA+0!=0
3121                  | SQLITE_TrustedSchema
3122 #endif
3123 /* The SQLITE_DQS compile-time option determines the default settings
3124 ** for SQLITE_DBCONFIG_DQS_DDL and SQLITE_DBCONFIG_DQS_DML.
3125 **
3126 **    SQLITE_DQS     SQLITE_DBCONFIG_DQS_DDL    SQLITE_DBCONFIG_DQS_DML
3127 **    ----------     -----------------------    -----------------------
3128 **     undefined               on                          on
3129 **         3                   on                          on
3130 **         2                   on                         off
3131 **         1                  off                          on
3132 **         0                  off                         off
3133 **
3134 ** Legacy behavior is 3 (double-quoted string literals are allowed anywhere)
3135 ** and so that is the default.  But developers are encouranged to use
3136 ** -DSQLITE_DQS=0 (best) or -DSQLITE_DQS=1 (second choice) if possible.
3137 */
3138 #if !defined(SQLITE_DQS)
3139 # define SQLITE_DQS 3
3140 #endif
3141 #if (SQLITE_DQS&1)==1
3142                  | SQLITE_DqsDML
3143 #endif
3144 #if (SQLITE_DQS&2)==2
3145                  | SQLITE_DqsDDL
3146 #endif
3147 
3148 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
3149                  | SQLITE_AutoIndex
3150 #endif
3151 #if SQLITE_DEFAULT_CKPTFULLFSYNC
3152                  | SQLITE_CkptFullFSync
3153 #endif
3154 #if SQLITE_DEFAULT_FILE_FORMAT<4
3155                  | SQLITE_LegacyFileFmt
3156 #endif
3157 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
3158                  | SQLITE_LoadExtension
3159 #endif
3160 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
3161                  | SQLITE_RecTriggers
3162 #endif
3163 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
3164                  | SQLITE_ForeignKeys
3165 #endif
3166 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
3167                  | SQLITE_ReverseOrder
3168 #endif
3169 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
3170                  | SQLITE_CellSizeCk
3171 #endif
3172 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
3173                  | SQLITE_Fts3Tokenizer
3174 #endif
3175 #if defined(SQLITE_ENABLE_QPSG)
3176                  | SQLITE_EnableQPSG
3177 #endif
3178 #if defined(SQLITE_DEFAULT_DEFENSIVE)
3179                  | SQLITE_Defensive
3180 #endif
3181       ;
3182   sqlite3HashInit(&db->aCollSeq);
3183 #ifndef SQLITE_OMIT_VIRTUALTABLE
3184   sqlite3HashInit(&db->aModule);
3185 #endif
3186 
3187   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
3188   ** and UTF-16, so add a version for each to avoid any unnecessary
3189   ** conversions. The only error that can occur here is a malloc() failure.
3190   **
3191   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
3192   ** functions:
3193   */
3194   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
3195   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
3196   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
3197   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
3198   createCollation(db, "RTRIM", SQLITE_UTF8, 0, rtrimCollFunc, 0);
3199   if( db->mallocFailed ){
3200     goto opendb_out;
3201   }
3202   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
3203   ** strings is BINARY.
3204   */
3205   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
3206   assert( db->pDfltColl!=0 );
3207 
3208   /* Parse the filename/URI argument
3209   **
3210   ** Only allow sensible combinations of bits in the flags argument.
3211   ** Throw an error if any non-sense combination is used.  If we
3212   ** do not block illegal combinations here, it could trigger
3213   ** assert() statements in deeper layers.  Sensible combinations
3214   ** are:
3215   **
3216   **  1:  SQLITE_OPEN_READONLY
3217   **  2:  SQLITE_OPEN_READWRITE
3218   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
3219   */
3220   db->openFlags = flags;
3221   assert( SQLITE_OPEN_READONLY  == 0x01 );
3222   assert( SQLITE_OPEN_READWRITE == 0x02 );
3223   assert( SQLITE_OPEN_CREATE    == 0x04 );
3224   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
3225   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
3226   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
3227   if( ((1<<(flags&7)) & 0x46)==0 ){
3228     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
3229   }else{
3230     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
3231   }
3232   if( rc!=SQLITE_OK ){
3233     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
3234     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
3235     sqlite3_free(zErrMsg);
3236     goto opendb_out;
3237   }
3238 
3239   /* Open the backend database driver */
3240   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
3241                         flags | SQLITE_OPEN_MAIN_DB);
3242   if( rc!=SQLITE_OK ){
3243     if( rc==SQLITE_IOERR_NOMEM ){
3244       rc = SQLITE_NOMEM_BKPT;
3245     }
3246     sqlite3Error(db, rc);
3247     goto opendb_out;
3248   }
3249   sqlite3BtreeEnter(db->aDb[0].pBt);
3250   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
3251   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
3252   sqlite3BtreeLeave(db->aDb[0].pBt);
3253   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
3254 
3255   /* The default safety_level for the main database is FULL; for the temp
3256   ** database it is OFF. This matches the pager layer defaults.
3257   */
3258   db->aDb[0].zDbSName = "main";
3259   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
3260   db->aDb[1].zDbSName = "temp";
3261   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
3262 
3263   db->magic = SQLITE_MAGIC_OPEN;
3264   if( db->mallocFailed ){
3265     goto opendb_out;
3266   }
3267 
3268   /* Register all built-in functions, but do not attempt to read the
3269   ** database schema yet. This is delayed until the first time the database
3270   ** is accessed.
3271   */
3272   sqlite3Error(db, SQLITE_OK);
3273   sqlite3RegisterPerConnectionBuiltinFunctions(db);
3274   rc = sqlite3_errcode(db);
3275 
3276 #ifdef SQLITE_ENABLE_FTS5
3277   /* Register any built-in FTS5 module before loading the automatic
3278   ** extensions. This allows automatic extensions to register FTS5
3279   ** tokenizers and auxiliary functions.  */
3280   if( !db->mallocFailed && rc==SQLITE_OK ){
3281     rc = sqlite3Fts5Init(db);
3282   }
3283 #endif
3284 
3285   /* Load automatic extensions - extensions that have been registered
3286   ** using the sqlite3_automatic_extension() API.
3287   */
3288   if( rc==SQLITE_OK ){
3289     sqlite3AutoLoadExtensions(db);
3290     rc = sqlite3_errcode(db);
3291     if( rc!=SQLITE_OK ){
3292       goto opendb_out;
3293     }
3294   }
3295 
3296 #ifdef SQLITE_ENABLE_FTS1
3297   if( !db->mallocFailed ){
3298     extern int sqlite3Fts1Init(sqlite3*);
3299     rc = sqlite3Fts1Init(db);
3300   }
3301 #endif
3302 
3303 #ifdef SQLITE_ENABLE_FTS2
3304   if( !db->mallocFailed && rc==SQLITE_OK ){
3305     extern int sqlite3Fts2Init(sqlite3*);
3306     rc = sqlite3Fts2Init(db);
3307   }
3308 #endif
3309 
3310 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3311   if( !db->mallocFailed && rc==SQLITE_OK ){
3312     rc = sqlite3Fts3Init(db);
3313   }
3314 #endif
3315 
3316 #if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
3317   if( !db->mallocFailed && rc==SQLITE_OK ){
3318     rc = sqlite3IcuInit(db);
3319   }
3320 #endif
3321 
3322 #ifdef SQLITE_ENABLE_RTREE
3323   if( !db->mallocFailed && rc==SQLITE_OK){
3324     rc = sqlite3RtreeInit(db);
3325   }
3326 #endif
3327 
3328 #ifdef SQLITE_ENABLE_DBPAGE_VTAB
3329   if( !db->mallocFailed && rc==SQLITE_OK){
3330     rc = sqlite3DbpageRegister(db);
3331   }
3332 #endif
3333 
3334 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3335   if( !db->mallocFailed && rc==SQLITE_OK){
3336     rc = sqlite3DbstatRegister(db);
3337   }
3338 #endif
3339 
3340 #ifdef SQLITE_ENABLE_JSON1
3341   if( !db->mallocFailed && rc==SQLITE_OK){
3342     rc = sqlite3Json1Init(db);
3343   }
3344 #endif
3345 
3346 #ifdef SQLITE_ENABLE_STMTVTAB
3347   if( !db->mallocFailed && rc==SQLITE_OK){
3348     rc = sqlite3StmtVtabInit(db);
3349   }
3350 #endif
3351 
3352 #ifdef SQLITE_ENABLE_INTERNAL_FUNCTIONS
3353   /* Testing use only!!! The -DSQLITE_ENABLE_INTERNAL_FUNCTIONS=1 compile-time
3354   ** option gives access to internal functions by default.
3355   ** Testing use only!!! */
3356   db->mDbFlags |= DBFLAG_InternalFunc;
3357 #endif
3358 
3359   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3360   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3361   ** mode.  Doing nothing at all also makes NORMAL the default.
3362   */
3363 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3364   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3365   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3366                           SQLITE_DEFAULT_LOCKING_MODE);
3367 #endif
3368 
3369   if( rc ) sqlite3Error(db, rc);
3370 
3371   /* Enable the lookaside-malloc subsystem */
3372   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3373                         sqlite3GlobalConfig.nLookaside);
3374 
3375   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3376 
3377 opendb_out:
3378   if( db ){
3379     assert( db->mutex!=0 || isThreadsafe==0
3380            || sqlite3GlobalConfig.bFullMutex==0 );
3381     sqlite3_mutex_leave(db->mutex);
3382   }
3383   rc = sqlite3_errcode(db);
3384   assert( db!=0 || rc==SQLITE_NOMEM );
3385   if( rc==SQLITE_NOMEM ){
3386     sqlite3_close(db);
3387     db = 0;
3388   }else if( rc!=SQLITE_OK ){
3389     db->magic = SQLITE_MAGIC_SICK;
3390   }
3391   *ppDb = db;
3392 #ifdef SQLITE_ENABLE_SQLLOG
3393   if( sqlite3GlobalConfig.xSqllog ){
3394     /* Opening a db handle. Fourth parameter is passed 0. */
3395     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3396     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3397   }
3398 #endif
3399   sqlite3_free_filename(zOpen);
3400   return rc & 0xff;
3401 }
3402 
3403 
3404 /*
3405 ** Open a new database handle.
3406 */
3407 int sqlite3_open(
3408   const char *zFilename,
3409   sqlite3 **ppDb
3410 ){
3411   return openDatabase(zFilename, ppDb,
3412                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3413 }
3414 int sqlite3_open_v2(
3415   const char *filename,   /* Database filename (UTF-8) */
3416   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3417   int flags,              /* Flags */
3418   const char *zVfs        /* Name of VFS module to use */
3419 ){
3420   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3421 }
3422 
3423 #ifndef SQLITE_OMIT_UTF16
3424 /*
3425 ** Open a new database handle.
3426 */
3427 int sqlite3_open16(
3428   const void *zFilename,
3429   sqlite3 **ppDb
3430 ){
3431   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3432   sqlite3_value *pVal;
3433   int rc;
3434 
3435 #ifdef SQLITE_ENABLE_API_ARMOR
3436   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3437 #endif
3438   *ppDb = 0;
3439 #ifndef SQLITE_OMIT_AUTOINIT
3440   rc = sqlite3_initialize();
3441   if( rc ) return rc;
3442 #endif
3443   if( zFilename==0 ) zFilename = "\000\000";
3444   pVal = sqlite3ValueNew(0);
3445   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3446   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3447   if( zFilename8 ){
3448     rc = openDatabase(zFilename8, ppDb,
3449                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3450     assert( *ppDb || rc==SQLITE_NOMEM );
3451     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3452       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3453     }
3454   }else{
3455     rc = SQLITE_NOMEM_BKPT;
3456   }
3457   sqlite3ValueFree(pVal);
3458 
3459   return rc & 0xff;
3460 }
3461 #endif /* SQLITE_OMIT_UTF16 */
3462 
3463 /*
3464 ** Register a new collation sequence with the database handle db.
3465 */
3466 int sqlite3_create_collation(
3467   sqlite3* db,
3468   const char *zName,
3469   int enc,
3470   void* pCtx,
3471   int(*xCompare)(void*,int,const void*,int,const void*)
3472 ){
3473   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3474 }
3475 
3476 /*
3477 ** Register a new collation sequence with the database handle db.
3478 */
3479 int sqlite3_create_collation_v2(
3480   sqlite3* db,
3481   const char *zName,
3482   int enc,
3483   void* pCtx,
3484   int(*xCompare)(void*,int,const void*,int,const void*),
3485   void(*xDel)(void*)
3486 ){
3487   int rc;
3488 
3489 #ifdef SQLITE_ENABLE_API_ARMOR
3490   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3491 #endif
3492   sqlite3_mutex_enter(db->mutex);
3493   assert( !db->mallocFailed );
3494   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3495   rc = sqlite3ApiExit(db, rc);
3496   sqlite3_mutex_leave(db->mutex);
3497   return rc;
3498 }
3499 
3500 #ifndef SQLITE_OMIT_UTF16
3501 /*
3502 ** Register a new collation sequence with the database handle db.
3503 */
3504 int sqlite3_create_collation16(
3505   sqlite3* db,
3506   const void *zName,
3507   int enc,
3508   void* pCtx,
3509   int(*xCompare)(void*,int,const void*,int,const void*)
3510 ){
3511   int rc = SQLITE_OK;
3512   char *zName8;
3513 
3514 #ifdef SQLITE_ENABLE_API_ARMOR
3515   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3516 #endif
3517   sqlite3_mutex_enter(db->mutex);
3518   assert( !db->mallocFailed );
3519   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3520   if( zName8 ){
3521     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3522     sqlite3DbFree(db, zName8);
3523   }
3524   rc = sqlite3ApiExit(db, rc);
3525   sqlite3_mutex_leave(db->mutex);
3526   return rc;
3527 }
3528 #endif /* SQLITE_OMIT_UTF16 */
3529 
3530 /*
3531 ** Register a collation sequence factory callback with the database handle
3532 ** db. Replace any previously installed collation sequence factory.
3533 */
3534 int sqlite3_collation_needed(
3535   sqlite3 *db,
3536   void *pCollNeededArg,
3537   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3538 ){
3539 #ifdef SQLITE_ENABLE_API_ARMOR
3540   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3541 #endif
3542   sqlite3_mutex_enter(db->mutex);
3543   db->xCollNeeded = xCollNeeded;
3544   db->xCollNeeded16 = 0;
3545   db->pCollNeededArg = pCollNeededArg;
3546   sqlite3_mutex_leave(db->mutex);
3547   return SQLITE_OK;
3548 }
3549 
3550 #ifndef SQLITE_OMIT_UTF16
3551 /*
3552 ** Register a collation sequence factory callback with the database handle
3553 ** db. Replace any previously installed collation sequence factory.
3554 */
3555 int sqlite3_collation_needed16(
3556   sqlite3 *db,
3557   void *pCollNeededArg,
3558   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3559 ){
3560 #ifdef SQLITE_ENABLE_API_ARMOR
3561   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3562 #endif
3563   sqlite3_mutex_enter(db->mutex);
3564   db->xCollNeeded = 0;
3565   db->xCollNeeded16 = xCollNeeded16;
3566   db->pCollNeededArg = pCollNeededArg;
3567   sqlite3_mutex_leave(db->mutex);
3568   return SQLITE_OK;
3569 }
3570 #endif /* SQLITE_OMIT_UTF16 */
3571 
3572 #ifndef SQLITE_OMIT_DEPRECATED
3573 /*
3574 ** This function is now an anachronism. It used to be used to recover from a
3575 ** malloc() failure, but SQLite now does this automatically.
3576 */
3577 int sqlite3_global_recover(void){
3578   return SQLITE_OK;
3579 }
3580 #endif
3581 
3582 /*
3583 ** Test to see whether or not the database connection is in autocommit
3584 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3585 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3586 ** by the next COMMIT or ROLLBACK.
3587 */
3588 int sqlite3_get_autocommit(sqlite3 *db){
3589 #ifdef SQLITE_ENABLE_API_ARMOR
3590   if( !sqlite3SafetyCheckOk(db) ){
3591     (void)SQLITE_MISUSE_BKPT;
3592     return 0;
3593   }
3594 #endif
3595   return db->autoCommit;
3596 }
3597 
3598 /*
3599 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3600 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3601 ** constants.  They serve two purposes:
3602 **
3603 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3604 **       to detect when version error conditions occurs.
3605 **
3606 **   2.  Invoke sqlite3_log() to provide the source code location where
3607 **       a low-level error is first detected.
3608 */
3609 int sqlite3ReportError(int iErr, int lineno, const char *zType){
3610   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3611               zType, lineno, 20+sqlite3_sourceid());
3612   return iErr;
3613 }
3614 int sqlite3CorruptError(int lineno){
3615   testcase( sqlite3GlobalConfig.xLog!=0 );
3616   return sqlite3ReportError(SQLITE_CORRUPT, lineno, "database corruption");
3617 }
3618 int sqlite3MisuseError(int lineno){
3619   testcase( sqlite3GlobalConfig.xLog!=0 );
3620   return sqlite3ReportError(SQLITE_MISUSE, lineno, "misuse");
3621 }
3622 int sqlite3CantopenError(int lineno){
3623   testcase( sqlite3GlobalConfig.xLog!=0 );
3624   return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3625 }
3626 #if defined(SQLITE_DEBUG) || defined(SQLITE_ENABLE_CORRUPT_PGNO)
3627 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3628   char zMsg[100];
3629   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3630   testcase( sqlite3GlobalConfig.xLog!=0 );
3631   return sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
3632 }
3633 #endif
3634 #ifdef SQLITE_DEBUG
3635 int sqlite3NomemError(int lineno){
3636   testcase( sqlite3GlobalConfig.xLog!=0 );
3637   return sqlite3ReportError(SQLITE_NOMEM, lineno, "OOM");
3638 }
3639 int sqlite3IoerrnomemError(int lineno){
3640   testcase( sqlite3GlobalConfig.xLog!=0 );
3641   return sqlite3ReportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3642 }
3643 #endif
3644 
3645 #ifndef SQLITE_OMIT_DEPRECATED
3646 /*
3647 ** This is a convenience routine that makes sure that all thread-specific
3648 ** data for this thread has been deallocated.
3649 **
3650 ** SQLite no longer uses thread-specific data so this routine is now a
3651 ** no-op.  It is retained for historical compatibility.
3652 */
3653 void sqlite3_thread_cleanup(void){
3654 }
3655 #endif
3656 
3657 /*
3658 ** Return meta information about a specific column of a database table.
3659 ** See comment in sqlite3.h (sqlite.h.in) for details.
3660 */
3661 int sqlite3_table_column_metadata(
3662   sqlite3 *db,                /* Connection handle */
3663   const char *zDbName,        /* Database name or NULL */
3664   const char *zTableName,     /* Table name */
3665   const char *zColumnName,    /* Column name */
3666   char const **pzDataType,    /* OUTPUT: Declared data type */
3667   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3668   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3669   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3670   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3671 ){
3672   int rc;
3673   char *zErrMsg = 0;
3674   Table *pTab = 0;
3675   Column *pCol = 0;
3676   int iCol = 0;
3677   char const *zDataType = 0;
3678   char const *zCollSeq = 0;
3679   int notnull = 0;
3680   int primarykey = 0;
3681   int autoinc = 0;
3682 
3683 
3684 #ifdef SQLITE_ENABLE_API_ARMOR
3685   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3686     return SQLITE_MISUSE_BKPT;
3687   }
3688 #endif
3689 
3690   /* Ensure the database schema has been loaded */
3691   sqlite3_mutex_enter(db->mutex);
3692   sqlite3BtreeEnterAll(db);
3693   rc = sqlite3Init(db, &zErrMsg);
3694   if( SQLITE_OK!=rc ){
3695     goto error_out;
3696   }
3697 
3698   /* Locate the table in question */
3699   pTab = sqlite3FindTable(db, zTableName, zDbName);
3700   if( !pTab || pTab->pSelect ){
3701     pTab = 0;
3702     goto error_out;
3703   }
3704 
3705   /* Find the column for which info is requested */
3706   if( zColumnName==0 ){
3707     /* Query for existance of table only */
3708   }else{
3709     for(iCol=0; iCol<pTab->nCol; iCol++){
3710       pCol = &pTab->aCol[iCol];
3711       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3712         break;
3713       }
3714     }
3715     if( iCol==pTab->nCol ){
3716       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3717         iCol = pTab->iPKey;
3718         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3719       }else{
3720         pTab = 0;
3721         goto error_out;
3722       }
3723     }
3724   }
3725 
3726   /* The following block stores the meta information that will be returned
3727   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3728   ** and autoinc. At this point there are two possibilities:
3729   **
3730   **     1. The specified column name was rowid", "oid" or "_rowid_"
3731   **        and there is no explicitly declared IPK column.
3732   **
3733   **     2. The table is not a view and the column name identified an
3734   **        explicitly declared column. Copy meta information from *pCol.
3735   */
3736   if( pCol ){
3737     zDataType = sqlite3ColumnType(pCol,0);
3738     zCollSeq = pCol->zColl;
3739     notnull = pCol->notNull!=0;
3740     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3741     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3742   }else{
3743     zDataType = "INTEGER";
3744     primarykey = 1;
3745   }
3746   if( !zCollSeq ){
3747     zCollSeq = sqlite3StrBINARY;
3748   }
3749 
3750 error_out:
3751   sqlite3BtreeLeaveAll(db);
3752 
3753   /* Whether the function call succeeded or failed, set the output parameters
3754   ** to whatever their local counterparts contain. If an error did occur,
3755   ** this has the effect of zeroing all output parameters.
3756   */
3757   if( pzDataType ) *pzDataType = zDataType;
3758   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3759   if( pNotNull ) *pNotNull = notnull;
3760   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3761   if( pAutoinc ) *pAutoinc = autoinc;
3762 
3763   if( SQLITE_OK==rc && !pTab ){
3764     sqlite3DbFree(db, zErrMsg);
3765     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3766         zColumnName);
3767     rc = SQLITE_ERROR;
3768   }
3769   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3770   sqlite3DbFree(db, zErrMsg);
3771   rc = sqlite3ApiExit(db, rc);
3772   sqlite3_mutex_leave(db->mutex);
3773   return rc;
3774 }
3775 
3776 /*
3777 ** Sleep for a little while.  Return the amount of time slept.
3778 */
3779 int sqlite3_sleep(int ms){
3780   sqlite3_vfs *pVfs;
3781   int rc;
3782   pVfs = sqlite3_vfs_find(0);
3783   if( pVfs==0 ) return 0;
3784 
3785   /* This function works in milliseconds, but the underlying OsSleep()
3786   ** API uses microseconds. Hence the 1000's.
3787   */
3788   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3789   return rc;
3790 }
3791 
3792 /*
3793 ** Enable or disable the extended result codes.
3794 */
3795 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3796 #ifdef SQLITE_ENABLE_API_ARMOR
3797   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3798 #endif
3799   sqlite3_mutex_enter(db->mutex);
3800   db->errMask = onoff ? 0xffffffff : 0xff;
3801   sqlite3_mutex_leave(db->mutex);
3802   return SQLITE_OK;
3803 }
3804 
3805 /*
3806 ** Invoke the xFileControl method on a particular database.
3807 */
3808 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3809   int rc = SQLITE_ERROR;
3810   Btree *pBtree;
3811 
3812 #ifdef SQLITE_ENABLE_API_ARMOR
3813   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3814 #endif
3815   sqlite3_mutex_enter(db->mutex);
3816   pBtree = sqlite3DbNameToBtree(db, zDbName);
3817   if( pBtree ){
3818     Pager *pPager;
3819     sqlite3_file *fd;
3820     sqlite3BtreeEnter(pBtree);
3821     pPager = sqlite3BtreePager(pBtree);
3822     assert( pPager!=0 );
3823     fd = sqlite3PagerFile(pPager);
3824     assert( fd!=0 );
3825     if( op==SQLITE_FCNTL_FILE_POINTER ){
3826       *(sqlite3_file**)pArg = fd;
3827       rc = SQLITE_OK;
3828     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3829       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3830       rc = SQLITE_OK;
3831     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3832       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3833       rc = SQLITE_OK;
3834     }else if( op==SQLITE_FCNTL_DATA_VERSION ){
3835       *(unsigned int*)pArg = sqlite3PagerDataVersion(pPager);
3836       rc = SQLITE_OK;
3837     }else{
3838       rc = sqlite3OsFileControl(fd, op, pArg);
3839     }
3840     sqlite3BtreeLeave(pBtree);
3841   }
3842   sqlite3_mutex_leave(db->mutex);
3843   return rc;
3844 }
3845 
3846 /*
3847 ** Interface to the testing logic.
3848 */
3849 int sqlite3_test_control(int op, ...){
3850   int rc = 0;
3851 #ifdef SQLITE_UNTESTABLE
3852   UNUSED_PARAMETER(op);
3853 #else
3854   va_list ap;
3855   va_start(ap, op);
3856   switch( op ){
3857 
3858     /*
3859     ** Save the current state of the PRNG.
3860     */
3861     case SQLITE_TESTCTRL_PRNG_SAVE: {
3862       sqlite3PrngSaveState();
3863       break;
3864     }
3865 
3866     /*
3867     ** Restore the state of the PRNG to the last state saved using
3868     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3869     ** this verb acts like PRNG_RESET.
3870     */
3871     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3872       sqlite3PrngRestoreState();
3873       break;
3874     }
3875 
3876     /*  sqlite3_test_control(SQLITE_TESTCTRL_PRNG_SEED, int x, sqlite3 *db);
3877     **
3878     ** Control the seed for the pseudo-random number generator (PRNG) that
3879     ** is built into SQLite.  Cases:
3880     **
3881     **    x!=0 && db!=0       Seed the PRNG to the current value of the
3882     **                        schema cookie in the main database for db, or
3883     **                        x if the schema cookie is zero.  This case
3884     **                        is convenient to use with database fuzzers
3885     **                        as it allows the fuzzer some control over the
3886     **                        the PRNG seed.
3887     **
3888     **    x!=0 && db==0       Seed the PRNG to the value of x.
3889     **
3890     **    x==0 && db==0       Revert to default behavior of using the
3891     **                        xRandomness method on the primary VFS.
3892     **
3893     ** This test-control also resets the PRNG so that the new seed will
3894     ** be used for the next call to sqlite3_randomness().
3895     */
3896 #ifndef SQLITE_OMIT_WSD
3897     case SQLITE_TESTCTRL_PRNG_SEED: {
3898       int x = va_arg(ap, int);
3899       int y;
3900       sqlite3 *db = va_arg(ap, sqlite3*);
3901       assert( db==0 || db->aDb[0].pSchema!=0 );
3902       if( db && (y = db->aDb[0].pSchema->schema_cookie)!=0 ){ x = y; }
3903       sqlite3Config.iPrngSeed = x;
3904       sqlite3_randomness(0,0);
3905       break;
3906     }
3907 #endif
3908 
3909     /*
3910     **  sqlite3_test_control(BITVEC_TEST, size, program)
3911     **
3912     ** Run a test against a Bitvec object of size.  The program argument
3913     ** is an array of integers that defines the test.  Return -1 on a
3914     ** memory allocation error, 0 on success, or non-zero for an error.
3915     ** See the sqlite3BitvecBuiltinTest() for additional information.
3916     */
3917     case SQLITE_TESTCTRL_BITVEC_TEST: {
3918       int sz = va_arg(ap, int);
3919       int *aProg = va_arg(ap, int*);
3920       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3921       break;
3922     }
3923 
3924     /*
3925     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3926     **
3927     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3928     ** if xCallback is not NULL.
3929     **
3930     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3931     ** is called immediately after installing the new callback and the return
3932     ** value from sqlite3FaultSim(0) becomes the return from
3933     ** sqlite3_test_control().
3934     */
3935     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3936       /* MSVC is picky about pulling func ptrs from va lists.
3937       ** http://support.microsoft.com/kb/47961
3938       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3939       */
3940       typedef int(*TESTCALLBACKFUNC_t)(int);
3941       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3942       rc = sqlite3FaultSim(0);
3943       break;
3944     }
3945 
3946     /*
3947     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3948     **
3949     ** Register hooks to call to indicate which malloc() failures
3950     ** are benign.
3951     */
3952     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3953       typedef void (*void_function)(void);
3954       void_function xBenignBegin;
3955       void_function xBenignEnd;
3956       xBenignBegin = va_arg(ap, void_function);
3957       xBenignEnd = va_arg(ap, void_function);
3958       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3959       break;
3960     }
3961 
3962     /*
3963     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3964     **
3965     ** Set the PENDING byte to the value in the argument, if X>0.
3966     ** Make no changes if X==0.  Return the value of the pending byte
3967     ** as it existing before this routine was called.
3968     **
3969     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3970     ** an incompatible database file format.  Changing the PENDING byte
3971     ** while any database connection is open results in undefined and
3972     ** deleterious behavior.
3973     */
3974     case SQLITE_TESTCTRL_PENDING_BYTE: {
3975       rc = PENDING_BYTE;
3976 #ifndef SQLITE_OMIT_WSD
3977       {
3978         unsigned int newVal = va_arg(ap, unsigned int);
3979         if( newVal ) sqlite3PendingByte = newVal;
3980       }
3981 #endif
3982       break;
3983     }
3984 
3985     /*
3986     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3987     **
3988     ** This action provides a run-time test to see whether or not
3989     ** assert() was enabled at compile-time.  If X is true and assert()
3990     ** is enabled, then the return value is true.  If X is true and
3991     ** assert() is disabled, then the return value is zero.  If X is
3992     ** false and assert() is enabled, then the assertion fires and the
3993     ** process aborts.  If X is false and assert() is disabled, then the
3994     ** return value is zero.
3995     */
3996     case SQLITE_TESTCTRL_ASSERT: {
3997       volatile int x = 0;
3998       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3999       rc = x;
4000       break;
4001     }
4002 
4003 
4004     /*
4005     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
4006     **
4007     ** This action provides a run-time test to see how the ALWAYS and
4008     ** NEVER macros were defined at compile-time.
4009     **
4010     ** The return value is ALWAYS(X) if X is true, or 0 if X is false.
4011     **
4012     ** The recommended test is X==2.  If the return value is 2, that means
4013     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
4014     ** default setting.  If the return value is 1, then ALWAYS() is either
4015     ** hard-coded to true or else it asserts if its argument is false.
4016     ** The first behavior (hard-coded to true) is the case if
4017     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
4018     ** behavior (assert if the argument to ALWAYS() is false) is the case if
4019     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
4020     **
4021     ** The run-time test procedure might look something like this:
4022     **
4023     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
4024     **      // ALWAYS() and NEVER() are no-op pass-through macros
4025     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
4026     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
4027     **    }else{
4028     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
4029     **    }
4030     */
4031     case SQLITE_TESTCTRL_ALWAYS: {
4032       int x = va_arg(ap,int);
4033       rc = x ? ALWAYS(x) : 0;
4034       break;
4035     }
4036 
4037     /*
4038     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
4039     **
4040     ** The integer returned reveals the byte-order of the computer on which
4041     ** SQLite is running:
4042     **
4043     **       1     big-endian,    determined at run-time
4044     **      10     little-endian, determined at run-time
4045     **  432101     big-endian,    determined at compile-time
4046     **  123410     little-endian, determined at compile-time
4047     */
4048     case SQLITE_TESTCTRL_BYTEORDER: {
4049       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
4050       break;
4051     }
4052 
4053     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
4054     **
4055     ** Set the nReserve size to N for the main database on the database
4056     ** connection db.
4057     */
4058     case SQLITE_TESTCTRL_RESERVE: {
4059       sqlite3 *db = va_arg(ap, sqlite3*);
4060       int x = va_arg(ap,int);
4061       sqlite3_mutex_enter(db->mutex);
4062       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
4063       sqlite3_mutex_leave(db->mutex);
4064       break;
4065     }
4066 
4067     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
4068     **
4069     ** Enable or disable various optimizations for testing purposes.  The
4070     ** argument N is a bitmask of optimizations to be disabled.  For normal
4071     ** operation N should be 0.  The idea is that a test program (like the
4072     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
4073     ** with various optimizations disabled to verify that the same answer
4074     ** is obtained in every case.
4075     */
4076     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
4077       sqlite3 *db = va_arg(ap, sqlite3*);
4078       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
4079       break;
4080     }
4081 
4082     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
4083     **
4084     ** If parameter onoff is non-zero, subsequent calls to localtime()
4085     ** and its variants fail. If onoff is zero, undo this setting.
4086     */
4087     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
4088       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
4089       break;
4090     }
4091 
4092     /*   sqlite3_test_control(SQLITE_TESTCTRL_INTERNAL_FUNCTIONS, sqlite3*);
4093     **
4094     ** Toggle the ability to use internal functions on or off for
4095     ** the database connection given in the argument.
4096     */
4097     case SQLITE_TESTCTRL_INTERNAL_FUNCTIONS: {
4098       sqlite3 *db = va_arg(ap, sqlite3*);
4099       db->mDbFlags ^= DBFLAG_InternalFunc;
4100       break;
4101     }
4102 
4103     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
4104     **
4105     ** Set or clear a flag that indicates that the database file is always well-
4106     ** formed and never corrupt.  This flag is clear by default, indicating that
4107     ** database files might have arbitrary corruption.  Setting the flag during
4108     ** testing causes certain assert() statements in the code to be activated
4109     ** that demonstrat invariants on well-formed database files.
4110     */
4111     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
4112       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
4113       break;
4114     }
4115 
4116     /*   sqlite3_test_control(SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS, int);
4117     **
4118     ** Set or clear a flag that causes SQLite to verify that type, name,
4119     ** and tbl_name fields of the sqlite_master table.  This is normally
4120     ** on, but it is sometimes useful to turn it off for testing.
4121     */
4122     case SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS: {
4123       sqlite3GlobalConfig.bExtraSchemaChecks = va_arg(ap, int);
4124       break;
4125     }
4126 
4127     /* Set the threshold at which OP_Once counters reset back to zero.
4128     ** By default this is 0x7ffffffe (over 2 billion), but that value is
4129     ** too big to test in a reasonable amount of time, so this control is
4130     ** provided to set a small and easily reachable reset value.
4131     */
4132     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
4133       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
4134       break;
4135     }
4136 
4137     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
4138     **
4139     ** Set the VDBE coverage callback function to xCallback with context
4140     ** pointer ptr.
4141     */
4142     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
4143 #ifdef SQLITE_VDBE_COVERAGE
4144       typedef void (*branch_callback)(void*,unsigned int,
4145                                       unsigned char,unsigned char);
4146       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
4147       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
4148 #endif
4149       break;
4150     }
4151 
4152     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
4153     case SQLITE_TESTCTRL_SORTER_MMAP: {
4154       sqlite3 *db = va_arg(ap, sqlite3*);
4155       db->nMaxSorterMmap = va_arg(ap, int);
4156       break;
4157     }
4158 
4159     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
4160     **
4161     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
4162     ** not.
4163     */
4164     case SQLITE_TESTCTRL_ISINIT: {
4165       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
4166       break;
4167     }
4168 
4169     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
4170     **
4171     ** This test control is used to create imposter tables.  "db" is a pointer
4172     ** to the database connection.  dbName is the database name (ex: "main" or
4173     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
4174     ** or off.  "tnum" is the root page of the b-tree to which the imposter
4175     ** table should connect.
4176     **
4177     ** Enable imposter mode only when the schema has already been parsed.  Then
4178     ** run a single CREATE TABLE statement to construct the imposter table in
4179     ** the parsed schema.  Then turn imposter mode back off again.
4180     **
4181     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
4182     ** the schema to be reparsed the next time it is needed.  This has the
4183     ** effect of erasing all imposter tables.
4184     */
4185     case SQLITE_TESTCTRL_IMPOSTER: {
4186       sqlite3 *db = va_arg(ap, sqlite3*);
4187       sqlite3_mutex_enter(db->mutex);
4188       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
4189       db->init.busy = db->init.imposterTable = va_arg(ap,int);
4190       db->init.newTnum = va_arg(ap,int);
4191       if( db->init.busy==0 && db->init.newTnum>0 ){
4192         sqlite3ResetAllSchemasOfConnection(db);
4193       }
4194       sqlite3_mutex_leave(db->mutex);
4195       break;
4196     }
4197 
4198 #if defined(YYCOVERAGE)
4199     /*  sqlite3_test_control(SQLITE_TESTCTRL_PARSER_COVERAGE, FILE *out)
4200     **
4201     ** This test control (only available when SQLite is compiled with
4202     ** -DYYCOVERAGE) writes a report onto "out" that shows all
4203     ** state/lookahead combinations in the parser state machine
4204     ** which are never exercised.  If any state is missed, make the
4205     ** return code SQLITE_ERROR.
4206     */
4207     case SQLITE_TESTCTRL_PARSER_COVERAGE: {
4208       FILE *out = va_arg(ap, FILE*);
4209       if( sqlite3ParserCoverage(out) ) rc = SQLITE_ERROR;
4210       break;
4211     }
4212 #endif /* defined(YYCOVERAGE) */
4213 
4214     /*  sqlite3_test_control(SQLITE_TESTCTRL_RESULT_INTREAL, sqlite3_context*);
4215     **
4216     ** This test-control causes the most recent sqlite3_result_int64() value
4217     ** to be interpreted as a MEM_IntReal instead of as an MEM_Int.  Normally,
4218     ** MEM_IntReal values only arise during an INSERT operation of integer
4219     ** values into a REAL column, so they can be challenging to test.  This
4220     ** test-control enables us to write an intreal() SQL function that can
4221     ** inject an intreal() value at arbitrary places in an SQL statement,
4222     ** for testing purposes.
4223     */
4224     case SQLITE_TESTCTRL_RESULT_INTREAL: {
4225       sqlite3_context *pCtx = va_arg(ap, sqlite3_context*);
4226       sqlite3ResultIntReal(pCtx);
4227       break;
4228     }
4229   }
4230   va_end(ap);
4231 #endif /* SQLITE_UNTESTABLE */
4232   return rc;
4233 }
4234 
4235 /*
4236 ** The Pager stores the Database filename, Journal filename, and WAL filename
4237 ** consecutively in memory, in that order.  The database filename is prefixed
4238 ** by four zero bytes.  Locate the start of the database filename by searching
4239 ** backwards for the first byte following four consecutive zero bytes.
4240 **
4241 ** This only works if the filename passed in was obtained from the Pager.
4242 */
4243 static const char *databaseName(const char *zName){
4244   while( zName[-1]!=0 || zName[-2]!=0 || zName[-3]!=0 || zName[-4]!=0 ){
4245     zName--;
4246   }
4247   return zName;
4248 }
4249 
4250 /*
4251 ** Append text z[] to the end of p[].  Return a pointer to the first
4252 ** character after then zero terminator on the new text in p[].
4253 */
4254 static char *appendText(char *p, const char *z){
4255   size_t n = strlen(z);
4256   memcpy(p, z, n+1);
4257   return p+n+1;
4258 }
4259 
4260 /*
4261 ** Allocate memory to hold names for a database, journal file, WAL file,
4262 ** and query parameters.  The pointer returned is valid for use by
4263 ** sqlite3_filename_database() and sqlite3_uri_parameter() and related
4264 ** functions.
4265 **
4266 ** Memory layout must be compatible with that generated by the pager
4267 ** and expected by sqlite3_uri_parameter() and databaseName().
4268 */
4269 char *sqlite3_create_filename(
4270   const char *zDatabase,
4271   const char *zJournal,
4272   const char *zWal,
4273   int nParam,
4274   const char **azParam
4275 ){
4276   sqlite3_int64 nByte;
4277   int i;
4278   char *pResult, *p;
4279   nByte = strlen(zDatabase) + strlen(zJournal) + strlen(zWal) + 10;
4280   for(i=0; i<nParam*2; i++){
4281     nByte += strlen(azParam[i])+1;
4282   }
4283   pResult = p = sqlite3_malloc64( nByte );
4284   if( p==0 ) return 0;
4285   memset(p, 0, 4);
4286   p += 4;
4287   p = appendText(p, zDatabase);
4288   for(i=0; i<nParam*2; i++){
4289     p = appendText(p, azParam[i]);
4290   }
4291   *(p++) = 0;
4292   p = appendText(p, zJournal);
4293   p = appendText(p, zWal);
4294   *(p++) = 0;
4295   *(p++) = 0;
4296   assert( (sqlite3_int64)(p - pResult)==nByte );
4297   return pResult + 4;
4298 }
4299 
4300 /*
4301 ** Free memory obtained from sqlite3_create_filename().  It is a severe
4302 ** error to call this routine with any parameter other than a pointer
4303 ** previously obtained from sqlite3_create_filename() or a NULL pointer.
4304 */
4305 void sqlite3_free_filename(char *p){
4306   if( p==0 ) return;
4307   p = (char*)databaseName(p);
4308   sqlite3_free(p - 4);
4309 }
4310 
4311 
4312 /*
4313 ** This is a utility routine, useful to VFS implementations, that checks
4314 ** to see if a database file was a URI that contained a specific query
4315 ** parameter, and if so obtains the value of the query parameter.
4316 **
4317 ** The zFilename argument is the filename pointer passed into the xOpen()
4318 ** method of a VFS implementation.  The zParam argument is the name of the
4319 ** query parameter we seek.  This routine returns the value of the zParam
4320 ** parameter if it exists.  If the parameter does not exist, this routine
4321 ** returns a NULL pointer.
4322 */
4323 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
4324   if( zFilename==0 || zParam==0 ) return 0;
4325   zFilename = databaseName(zFilename);
4326   return uriParameter(zFilename, zParam);
4327 }
4328 
4329 /*
4330 ** Return a pointer to the name of Nth query parameter of the filename.
4331 */
4332 const char *sqlite3_uri_key(const char *zFilename, int N){
4333   if( zFilename==0 || N<0 ) return 0;
4334   zFilename = databaseName(zFilename);
4335   zFilename += sqlite3Strlen30(zFilename) + 1;
4336   while( zFilename[0] && (N--)>0 ){
4337     zFilename += sqlite3Strlen30(zFilename) + 1;
4338     zFilename += sqlite3Strlen30(zFilename) + 1;
4339   }
4340   return zFilename[0] ? zFilename : 0;
4341 }
4342 
4343 /*
4344 ** Return a boolean value for a query parameter.
4345 */
4346 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
4347   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4348   bDflt = bDflt!=0;
4349   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
4350 }
4351 
4352 /*
4353 ** Return a 64-bit integer value for a query parameter.
4354 */
4355 sqlite3_int64 sqlite3_uri_int64(
4356   const char *zFilename,    /* Filename as passed to xOpen */
4357   const char *zParam,       /* URI parameter sought */
4358   sqlite3_int64 bDflt       /* return if parameter is missing */
4359 ){
4360   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4361   sqlite3_int64 v;
4362   if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
4363     bDflt = v;
4364   }
4365   return bDflt;
4366 }
4367 
4368 /*
4369 ** Translate a filename that was handed to a VFS routine into the corresponding
4370 ** database, journal, or WAL file.
4371 **
4372 ** It is an error to pass this routine a filename string that was not
4373 ** passed into the VFS from the SQLite core.  Doing so is similar to
4374 ** passing free() a pointer that was not obtained from malloc() - it is
4375 ** an error that we cannot easily detect but that will likely cause memory
4376 ** corruption.
4377 */
4378 const char *sqlite3_filename_database(const char *zFilename){
4379   return databaseName(zFilename);
4380 }
4381 const char *sqlite3_filename_journal(const char *zFilename){
4382   zFilename = databaseName(zFilename);
4383   zFilename += sqlite3Strlen30(zFilename) + 1;
4384   while( zFilename[0] ){
4385     zFilename += sqlite3Strlen30(zFilename) + 1;
4386     zFilename += sqlite3Strlen30(zFilename) + 1;
4387   }
4388   return zFilename + 1;
4389 }
4390 const char *sqlite3_filename_wal(const char *zFilename){
4391 #ifdef SQLITE_OMIT_WAL
4392   return 0;
4393 #else
4394   zFilename = sqlite3_filename_journal(zFilename);
4395   zFilename += sqlite3Strlen30(zFilename) + 1;
4396   return zFilename;
4397 #endif
4398 }
4399 
4400 /*
4401 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
4402 */
4403 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
4404   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
4405   return iDb<0 ? 0 : db->aDb[iDb].pBt;
4406 }
4407 
4408 /*
4409 ** Return the filename of the database associated with a database
4410 ** connection.
4411 */
4412 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
4413   Btree *pBt;
4414 #ifdef SQLITE_ENABLE_API_ARMOR
4415   if( !sqlite3SafetyCheckOk(db) ){
4416     (void)SQLITE_MISUSE_BKPT;
4417     return 0;
4418   }
4419 #endif
4420   pBt = sqlite3DbNameToBtree(db, zDbName);
4421   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
4422 }
4423 
4424 /*
4425 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
4426 ** no such database exists.
4427 */
4428 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
4429   Btree *pBt;
4430 #ifdef SQLITE_ENABLE_API_ARMOR
4431   if( !sqlite3SafetyCheckOk(db) ){
4432     (void)SQLITE_MISUSE_BKPT;
4433     return -1;
4434   }
4435 #endif
4436   pBt = sqlite3DbNameToBtree(db, zDbName);
4437   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
4438 }
4439 
4440 #ifdef SQLITE_ENABLE_SNAPSHOT
4441 /*
4442 ** Obtain a snapshot handle for the snapshot of database zDb currently
4443 ** being read by handle db.
4444 */
4445 int sqlite3_snapshot_get(
4446   sqlite3 *db,
4447   const char *zDb,
4448   sqlite3_snapshot **ppSnapshot
4449 ){
4450   int rc = SQLITE_ERROR;
4451 #ifndef SQLITE_OMIT_WAL
4452 
4453 #ifdef SQLITE_ENABLE_API_ARMOR
4454   if( !sqlite3SafetyCheckOk(db) ){
4455     return SQLITE_MISUSE_BKPT;
4456   }
4457 #endif
4458   sqlite3_mutex_enter(db->mutex);
4459 
4460   if( db->autoCommit==0 ){
4461     int iDb = sqlite3FindDbName(db, zDb);
4462     if( iDb==0 || iDb>1 ){
4463       Btree *pBt = db->aDb[iDb].pBt;
4464       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4465         rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4466         if( rc==SQLITE_OK ){
4467           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4468         }
4469       }
4470     }
4471   }
4472 
4473   sqlite3_mutex_leave(db->mutex);
4474 #endif   /* SQLITE_OMIT_WAL */
4475   return rc;
4476 }
4477 
4478 /*
4479 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4480 */
4481 int sqlite3_snapshot_open(
4482   sqlite3 *db,
4483   const char *zDb,
4484   sqlite3_snapshot *pSnapshot
4485 ){
4486   int rc = SQLITE_ERROR;
4487 #ifndef SQLITE_OMIT_WAL
4488 
4489 #ifdef SQLITE_ENABLE_API_ARMOR
4490   if( !sqlite3SafetyCheckOk(db) ){
4491     return SQLITE_MISUSE_BKPT;
4492   }
4493 #endif
4494   sqlite3_mutex_enter(db->mutex);
4495   if( db->autoCommit==0 ){
4496     int iDb;
4497     iDb = sqlite3FindDbName(db, zDb);
4498     if( iDb==0 || iDb>1 ){
4499       Btree *pBt = db->aDb[iDb].pBt;
4500       if( sqlite3BtreeIsInTrans(pBt)==0 ){
4501         Pager *pPager = sqlite3BtreePager(pBt);
4502         int bUnlock = 0;
4503         if( sqlite3BtreeIsInReadTrans(pBt) ){
4504           if( db->nVdbeActive==0 ){
4505             rc = sqlite3PagerSnapshotCheck(pPager, pSnapshot);
4506             if( rc==SQLITE_OK ){
4507               bUnlock = 1;
4508               rc = sqlite3BtreeCommit(pBt);
4509             }
4510           }
4511         }else{
4512           rc = SQLITE_OK;
4513         }
4514         if( rc==SQLITE_OK ){
4515           rc = sqlite3PagerSnapshotOpen(pPager, pSnapshot);
4516         }
4517         if( rc==SQLITE_OK ){
4518           rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4519           sqlite3PagerSnapshotOpen(pPager, 0);
4520         }
4521         if( bUnlock ){
4522           sqlite3PagerSnapshotUnlock(pPager);
4523         }
4524       }
4525     }
4526   }
4527 
4528   sqlite3_mutex_leave(db->mutex);
4529 #endif   /* SQLITE_OMIT_WAL */
4530   return rc;
4531 }
4532 
4533 /*
4534 ** Recover as many snapshots as possible from the wal file associated with
4535 ** schema zDb of database db.
4536 */
4537 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4538   int rc = SQLITE_ERROR;
4539   int iDb;
4540 #ifndef SQLITE_OMIT_WAL
4541 
4542 #ifdef SQLITE_ENABLE_API_ARMOR
4543   if( !sqlite3SafetyCheckOk(db) ){
4544     return SQLITE_MISUSE_BKPT;
4545   }
4546 #endif
4547 
4548   sqlite3_mutex_enter(db->mutex);
4549   iDb = sqlite3FindDbName(db, zDb);
4550   if( iDb==0 || iDb>1 ){
4551     Btree *pBt = db->aDb[iDb].pBt;
4552     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4553       rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4554       if( rc==SQLITE_OK ){
4555         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4556         sqlite3BtreeCommit(pBt);
4557       }
4558     }
4559   }
4560   sqlite3_mutex_leave(db->mutex);
4561 #endif   /* SQLITE_OMIT_WAL */
4562   return rc;
4563 }
4564 
4565 /*
4566 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4567 */
4568 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4569   sqlite3_free(pSnapshot);
4570 }
4571 #endif /* SQLITE_ENABLE_SNAPSHOT */
4572 
4573 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4574 /*
4575 ** Given the name of a compile-time option, return true if that option
4576 ** was used and false if not.
4577 **
4578 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4579 ** is not required for a match.
4580 */
4581 int sqlite3_compileoption_used(const char *zOptName){
4582   int i, n;
4583   int nOpt;
4584   const char **azCompileOpt;
4585 
4586 #if SQLITE_ENABLE_API_ARMOR
4587   if( zOptName==0 ){
4588     (void)SQLITE_MISUSE_BKPT;
4589     return 0;
4590   }
4591 #endif
4592 
4593   azCompileOpt = sqlite3CompileOptions(&nOpt);
4594 
4595   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4596   n = sqlite3Strlen30(zOptName);
4597 
4598   /* Since nOpt is normally in single digits, a linear search is
4599   ** adequate. No need for a binary search. */
4600   for(i=0; i<nOpt; i++){
4601     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4602      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4603     ){
4604       return 1;
4605     }
4606   }
4607   return 0;
4608 }
4609 
4610 /*
4611 ** Return the N-th compile-time option string.  If N is out of range,
4612 ** return a NULL pointer.
4613 */
4614 const char *sqlite3_compileoption_get(int N){
4615   int nOpt;
4616   const char **azCompileOpt;
4617   azCompileOpt = sqlite3CompileOptions(&nOpt);
4618   if( N>=0 && N<nOpt ){
4619     return azCompileOpt[N];
4620   }
4621   return 0;
4622 }
4623 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4624