xref: /sqlite-3.40.0/src/main.c (revision cdf88760)
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 ) return SQLITE_OK;
165 
166   /* Make sure the mutex subsystem is initialized.  If unable to
167   ** initialize the mutex subsystem, return early with the error.
168   ** If the system is so sick that we are unable to allocate a mutex,
169   ** there is not much SQLite is going to be able to do.
170   **
171   ** The mutex subsystem must take care of serializing its own
172   ** initialization.
173   */
174   rc = sqlite3MutexInit();
175   if( rc ) return rc;
176 
177   /* Initialize the malloc() system and the recursive pInitMutex mutex.
178   ** This operation is protected by the STATIC_MASTER mutex.  Note that
179   ** MutexAlloc() is called for a static mutex prior to initializing the
180   ** malloc subsystem - this implies that the allocation of a static
181   ** mutex must not require support from the malloc subsystem.
182   */
183   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
184   sqlite3_mutex_enter(pMaster);
185   sqlite3GlobalConfig.isMutexInit = 1;
186   if( !sqlite3GlobalConfig.isMallocInit ){
187     rc = sqlite3MallocInit();
188   }
189   if( rc==SQLITE_OK ){
190     sqlite3GlobalConfig.isMallocInit = 1;
191     if( !sqlite3GlobalConfig.pInitMutex ){
192       sqlite3GlobalConfig.pInitMutex =
193            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
194       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
195         rc = SQLITE_NOMEM_BKPT;
196       }
197     }
198   }
199   if( rc==SQLITE_OK ){
200     sqlite3GlobalConfig.nRefInitMutex++;
201   }
202   sqlite3_mutex_leave(pMaster);
203 
204   /* If rc is not SQLITE_OK at this point, then either the malloc
205   ** subsystem could not be initialized or the system failed to allocate
206   ** the pInitMutex mutex. Return an error in either case.  */
207   if( rc!=SQLITE_OK ){
208     return rc;
209   }
210 
211   /* Do the rest of the initialization under the recursive mutex so
212   ** that we will be able to handle recursive calls into
213   ** sqlite3_initialize().  The recursive calls normally come through
214   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
215   ** recursive calls might also be possible.
216   **
217   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
218   ** to the xInit method, so the xInit method need not be threadsafe.
219   **
220   ** The following mutex is what serializes access to the appdef pcache xInit
221   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
222   ** call to sqlite3PcacheInitialize().
223   */
224   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
225   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
226     sqlite3GlobalConfig.inProgress = 1;
227 #ifdef SQLITE_ENABLE_SQLLOG
228     {
229       extern void sqlite3_init_sqllog(void);
230       sqlite3_init_sqllog();
231     }
232 #endif
233     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
234     sqlite3RegisterBuiltinFunctions();
235     if( sqlite3GlobalConfig.isPCacheInit==0 ){
236       rc = sqlite3PcacheInitialize();
237     }
238     if( rc==SQLITE_OK ){
239       sqlite3GlobalConfig.isPCacheInit = 1;
240       rc = sqlite3OsInit();
241     }
242 #ifdef SQLITE_ENABLE_DESERIALIZE
243     if( rc==SQLITE_OK ){
244       rc = sqlite3MemdbInit();
245     }
246 #endif
247     if( rc==SQLITE_OK ){
248       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
249           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
250       sqlite3GlobalConfig.isInit = 1;
251 #ifdef SQLITE_EXTRA_INIT
252       bRunExtraInit = 1;
253 #endif
254     }
255     sqlite3GlobalConfig.inProgress = 0;
256   }
257   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
258 
259   /* Go back under the static mutex and clean up the recursive
260   ** mutex to prevent a resource leak.
261   */
262   sqlite3_mutex_enter(pMaster);
263   sqlite3GlobalConfig.nRefInitMutex--;
264   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
265     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
266     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
267     sqlite3GlobalConfig.pInitMutex = 0;
268   }
269   sqlite3_mutex_leave(pMaster);
270 
271   /* The following is just a sanity check to make sure SQLite has
272   ** been compiled correctly.  It is important to run this code, but
273   ** we don't want to run it too often and soak up CPU cycles for no
274   ** reason.  So we run it once during initialization.
275   */
276 #ifndef NDEBUG
277 #ifndef SQLITE_OMIT_FLOATING_POINT
278   /* This section of code's only "output" is via assert() statements. */
279   if( rc==SQLITE_OK ){
280     u64 x = (((u64)1)<<63)-1;
281     double y;
282     assert(sizeof(x)==8);
283     assert(sizeof(x)==sizeof(y));
284     memcpy(&y, &x, 8);
285     assert( sqlite3IsNaN(y) );
286   }
287 #endif
288 #endif
289 
290   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
291   ** compile-time option.
292   */
293 #ifdef SQLITE_EXTRA_INIT
294   if( bRunExtraInit ){
295     int SQLITE_EXTRA_INIT(const char*);
296     rc = SQLITE_EXTRA_INIT(0);
297   }
298 #endif
299 
300   return rc;
301 }
302 
303 /*
304 ** Undo the effects of sqlite3_initialize().  Must not be called while
305 ** there are outstanding database connections or memory allocations or
306 ** while any part of SQLite is otherwise in use in any thread.  This
307 ** routine is not threadsafe.  But it is safe to invoke this routine
308 ** on when SQLite is already shut down.  If SQLite is already shut down
309 ** when this routine is invoked, then this routine is a harmless no-op.
310 */
311 int sqlite3_shutdown(void){
312 #ifdef SQLITE_OMIT_WSD
313   int rc = sqlite3_wsd_init(4096, 24);
314   if( rc!=SQLITE_OK ){
315     return rc;
316   }
317 #endif
318 
319   if( sqlite3GlobalConfig.isInit ){
320 #ifdef SQLITE_EXTRA_SHUTDOWN
321     void SQLITE_EXTRA_SHUTDOWN(void);
322     SQLITE_EXTRA_SHUTDOWN();
323 #endif
324     sqlite3_os_end();
325     sqlite3_reset_auto_extension();
326     sqlite3GlobalConfig.isInit = 0;
327   }
328   if( sqlite3GlobalConfig.isPCacheInit ){
329     sqlite3PcacheShutdown();
330     sqlite3GlobalConfig.isPCacheInit = 0;
331   }
332   if( sqlite3GlobalConfig.isMallocInit ){
333     sqlite3MallocEnd();
334     sqlite3GlobalConfig.isMallocInit = 0;
335 
336 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
337     /* The heap subsystem has now been shutdown and these values are supposed
338     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
339     ** which would rely on that heap subsystem; therefore, make sure these
340     ** values cannot refer to heap memory that was just invalidated when the
341     ** heap subsystem was shutdown.  This is only done if the current call to
342     ** this function resulted in the heap subsystem actually being shutdown.
343     */
344     sqlite3_data_directory = 0;
345     sqlite3_temp_directory = 0;
346 #endif
347   }
348   if( sqlite3GlobalConfig.isMutexInit ){
349     sqlite3MutexEnd();
350     sqlite3GlobalConfig.isMutexInit = 0;
351   }
352 
353   return SQLITE_OK;
354 }
355 
356 /*
357 ** This API allows applications to modify the global configuration of
358 ** the SQLite library at run-time.
359 **
360 ** This routine should only be called when there are no outstanding
361 ** database connections or memory allocations.  This routine is not
362 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
363 ** behavior.
364 */
365 int sqlite3_config(int op, ...){
366   va_list ap;
367   int rc = SQLITE_OK;
368 
369   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
370   ** the SQLite library is in use. */
371   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
372 
373   va_start(ap, op);
374   switch( op ){
375 
376     /* Mutex configuration options are only available in a threadsafe
377     ** compile.
378     */
379 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
380     case SQLITE_CONFIG_SINGLETHREAD: {
381       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
382       ** Single-thread. */
383       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
384       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
385       break;
386     }
387 #endif
388 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
389     case SQLITE_CONFIG_MULTITHREAD: {
390       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
391       ** Multi-thread. */
392       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
393       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
394       break;
395     }
396 #endif
397 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
398     case SQLITE_CONFIG_SERIALIZED: {
399       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
400       ** Serialized. */
401       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
402       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
403       break;
404     }
405 #endif
406 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
407     case SQLITE_CONFIG_MUTEX: {
408       /* Specify an alternative mutex implementation */
409       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
410       break;
411     }
412 #endif
413 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
414     case SQLITE_CONFIG_GETMUTEX: {
415       /* Retrieve the current mutex implementation */
416       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
417       break;
418     }
419 #endif
420 
421     case SQLITE_CONFIG_MALLOC: {
422       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
423       ** single argument which is a pointer to an instance of the
424       ** sqlite3_mem_methods structure. The argument specifies alternative
425       ** low-level memory allocation routines to be used in place of the memory
426       ** allocation routines built into SQLite. */
427       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
428       break;
429     }
430     case SQLITE_CONFIG_GETMALLOC: {
431       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
432       ** single argument which is a pointer to an instance of the
433       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
434       ** filled with the currently defined memory allocation routines. */
435       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
436       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
437       break;
438     }
439     case SQLITE_CONFIG_MEMSTATUS: {
440       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
441       ** single argument of type int, interpreted as a boolean, which enables
442       ** or disables the collection of memory allocation statistics. */
443       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
444       break;
445     }
446     case SQLITE_CONFIG_SMALL_MALLOC: {
447       sqlite3GlobalConfig.bSmallMalloc = va_arg(ap, int);
448       break;
449     }
450     case SQLITE_CONFIG_PAGECACHE: {
451       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
452       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
453       ** the size of each page cache line (sz), and the number of cache lines
454       ** (N). */
455       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
456       sqlite3GlobalConfig.szPage = va_arg(ap, int);
457       sqlite3GlobalConfig.nPage = va_arg(ap, int);
458       break;
459     }
460     case SQLITE_CONFIG_PCACHE_HDRSZ: {
461       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
462       ** a single parameter which is a pointer to an integer and writes into
463       ** that integer the number of extra bytes per page required for each page
464       ** in SQLITE_CONFIG_PAGECACHE. */
465       *va_arg(ap, int*) =
466           sqlite3HeaderSizeBtree() +
467           sqlite3HeaderSizePcache() +
468           sqlite3HeaderSizePcache1();
469       break;
470     }
471 
472     case SQLITE_CONFIG_PCACHE: {
473       /* no-op */
474       break;
475     }
476     case SQLITE_CONFIG_GETPCACHE: {
477       /* now an error */
478       rc = SQLITE_ERROR;
479       break;
480     }
481 
482     case SQLITE_CONFIG_PCACHE2: {
483       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
484       ** single argument which is a pointer to an sqlite3_pcache_methods2
485       ** object. This object specifies the interface to a custom page cache
486       ** implementation. */
487       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
488       break;
489     }
490     case SQLITE_CONFIG_GETPCACHE2: {
491       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
492       ** single argument which is a pointer to an sqlite3_pcache_methods2
493       ** object. SQLite copies of the current page cache implementation into
494       ** that object. */
495       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
496         sqlite3PCacheSetDefault();
497       }
498       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
499       break;
500     }
501 
502 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
503 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
504 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
505 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
506     case SQLITE_CONFIG_HEAP: {
507       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
508       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
509       ** number of bytes in the memory buffer, and the minimum allocation size.
510       */
511       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
512       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
513       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
514 
515       if( sqlite3GlobalConfig.mnReq<1 ){
516         sqlite3GlobalConfig.mnReq = 1;
517       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
518         /* cap min request size at 2^12 */
519         sqlite3GlobalConfig.mnReq = (1<<12);
520       }
521 
522       if( sqlite3GlobalConfig.pHeap==0 ){
523         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
524         ** is NULL, then SQLite reverts to using its default memory allocator
525         ** (the system malloc() implementation), undoing any prior invocation of
526         ** SQLITE_CONFIG_MALLOC.
527         **
528         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
529         ** revert to its default implementation when sqlite3_initialize() is run
530         */
531         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
532       }else{
533         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
534         ** alternative memory allocator is engaged to handle all of SQLites
535         ** memory allocation needs. */
536 #ifdef SQLITE_ENABLE_MEMSYS3
537         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
538 #endif
539 #ifdef SQLITE_ENABLE_MEMSYS5
540         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
541 #endif
542       }
543       break;
544     }
545 #endif
546 
547     case SQLITE_CONFIG_LOOKASIDE: {
548       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
549       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
550       break;
551     }
552 
553     /* Record a pointer to the logger function and its first argument.
554     ** The default is NULL.  Logging is disabled if the function pointer is
555     ** NULL.
556     */
557     case SQLITE_CONFIG_LOG: {
558       /* MSVC is picky about pulling func ptrs from va lists.
559       ** http://support.microsoft.com/kb/47961
560       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
561       */
562       typedef void(*LOGFUNC_t)(void*,int,const char*);
563       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
564       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
565       break;
566     }
567 
568     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
569     ** can be changed at start-time using the
570     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
571     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
572     */
573     case SQLITE_CONFIG_URI: {
574       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
575       ** argument of type int. If non-zero, then URI handling is globally
576       ** enabled. If the parameter is zero, then URI handling is globally
577       ** disabled. */
578       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
579       break;
580     }
581 
582     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
583       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
584       ** option takes a single integer argument which is interpreted as a
585       ** boolean in order to enable or disable the use of covering indices for
586       ** full table scans in the query optimizer. */
587       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
588       break;
589     }
590 
591 #ifdef SQLITE_ENABLE_SQLLOG
592     case SQLITE_CONFIG_SQLLOG: {
593       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
594       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
595       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
596       break;
597     }
598 #endif
599 
600     case SQLITE_CONFIG_MMAP_SIZE: {
601       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
602       ** integer (sqlite3_int64) values that are the default mmap size limit
603       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
604       ** mmap size limit. */
605       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
606       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
607       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
608       ** negative, then that argument is changed to its compile-time default.
609       **
610       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
611       ** silently truncated if necessary so that it does not exceed the
612       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
613       ** compile-time option.
614       */
615       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
616         mxMmap = SQLITE_MAX_MMAP_SIZE;
617       }
618       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
619       if( szMmap>mxMmap) szMmap = mxMmap;
620       sqlite3GlobalConfig.mxMmap = mxMmap;
621       sqlite3GlobalConfig.szMmap = szMmap;
622       break;
623     }
624 
625 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
626     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
627       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
628       ** unsigned integer value that specifies the maximum size of the created
629       ** heap. */
630       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
631       break;
632     }
633 #endif
634 
635     case SQLITE_CONFIG_PMASZ: {
636       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
637       break;
638     }
639 
640     case SQLITE_CONFIG_STMTJRNL_SPILL: {
641       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
642       break;
643     }
644 
645 #ifdef SQLITE_ENABLE_SORTER_REFERENCES
646     case SQLITE_CONFIG_SORTERREF_SIZE: {
647       int iVal = va_arg(ap, int);
648       if( iVal<0 ){
649         iVal = SQLITE_DEFAULT_SORTERREF_SIZE;
650       }
651       sqlite3GlobalConfig.szSorterRef = (u32)iVal;
652       break;
653     }
654 #endif /* SQLITE_ENABLE_SORTER_REFERENCES */
655 
656     default: {
657       rc = SQLITE_ERROR;
658       break;
659     }
660   }
661   va_end(ap);
662   return rc;
663 }
664 
665 /*
666 ** Set up the lookaside buffers for a database connection.
667 ** Return SQLITE_OK on success.
668 ** If lookaside is already active, return SQLITE_BUSY.
669 **
670 ** The sz parameter is the number of bytes in each lookaside slot.
671 ** The cnt parameter is the number of slots.  If pStart is NULL the
672 ** space for the lookaside memory is obtained from sqlite3_malloc().
673 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
674 ** the lookaside memory.
675 */
676 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
677 #ifndef SQLITE_OMIT_LOOKASIDE
678   void *pStart;
679 
680   if( sqlite3LookasideUsed(db,0)>0 ){
681     return SQLITE_BUSY;
682   }
683   /* Free any existing lookaside buffer for this handle before
684   ** allocating a new one so we don't have to have space for
685   ** both at the same time.
686   */
687   if( db->lookaside.bMalloced ){
688     sqlite3_free(db->lookaside.pStart);
689   }
690   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
691   ** than a pointer to be useful.
692   */
693   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
694   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
695   if( cnt<0 ) cnt = 0;
696   if( sz==0 || cnt==0 ){
697     sz = 0;
698     pStart = 0;
699   }else if( pBuf==0 ){
700     sqlite3BeginBenignMalloc();
701     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
702     sqlite3EndBenignMalloc();
703     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
704   }else{
705     pStart = pBuf;
706   }
707   db->lookaside.pStart = pStart;
708   db->lookaside.pInit = 0;
709   db->lookaside.pFree = 0;
710   db->lookaside.sz = (u16)sz;
711   if( pStart ){
712     int i;
713     LookasideSlot *p;
714     assert( sz > (int)sizeof(LookasideSlot*) );
715     db->lookaside.nSlot = cnt;
716     p = (LookasideSlot*)pStart;
717     for(i=cnt-1; i>=0; i--){
718       p->pNext = db->lookaside.pInit;
719       db->lookaside.pInit = p;
720       p = (LookasideSlot*)&((u8*)p)[sz];
721     }
722     db->lookaside.pEnd = p;
723     db->lookaside.bDisable = 0;
724     db->lookaside.bMalloced = pBuf==0 ?1:0;
725   }else{
726     db->lookaside.pStart = db;
727     db->lookaside.pEnd = db;
728     db->lookaside.bDisable = 1;
729     db->lookaside.bMalloced = 0;
730     db->lookaside.nSlot = 0;
731   }
732 #endif /* SQLITE_OMIT_LOOKASIDE */
733   return SQLITE_OK;
734 }
735 
736 /*
737 ** Return the mutex associated with a database connection.
738 */
739 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
740 #ifdef SQLITE_ENABLE_API_ARMOR
741   if( !sqlite3SafetyCheckOk(db) ){
742     (void)SQLITE_MISUSE_BKPT;
743     return 0;
744   }
745 #endif
746   return db->mutex;
747 }
748 
749 /*
750 ** Free up as much memory as we can from the given database
751 ** connection.
752 */
753 int sqlite3_db_release_memory(sqlite3 *db){
754   int i;
755 
756 #ifdef SQLITE_ENABLE_API_ARMOR
757   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
758 #endif
759   sqlite3_mutex_enter(db->mutex);
760   sqlite3BtreeEnterAll(db);
761   for(i=0; i<db->nDb; i++){
762     Btree *pBt = db->aDb[i].pBt;
763     if( pBt ){
764       Pager *pPager = sqlite3BtreePager(pBt);
765       sqlite3PagerShrink(pPager);
766     }
767   }
768   sqlite3BtreeLeaveAll(db);
769   sqlite3_mutex_leave(db->mutex);
770   return SQLITE_OK;
771 }
772 
773 /*
774 ** Flush any dirty pages in the pager-cache for any attached database
775 ** to disk.
776 */
777 int sqlite3_db_cacheflush(sqlite3 *db){
778   int i;
779   int rc = SQLITE_OK;
780   int bSeenBusy = 0;
781 
782 #ifdef SQLITE_ENABLE_API_ARMOR
783   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
784 #endif
785   sqlite3_mutex_enter(db->mutex);
786   sqlite3BtreeEnterAll(db);
787   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
788     Btree *pBt = db->aDb[i].pBt;
789     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
790       Pager *pPager = sqlite3BtreePager(pBt);
791       rc = sqlite3PagerFlush(pPager);
792       if( rc==SQLITE_BUSY ){
793         bSeenBusy = 1;
794         rc = SQLITE_OK;
795       }
796     }
797   }
798   sqlite3BtreeLeaveAll(db);
799   sqlite3_mutex_leave(db->mutex);
800   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
801 }
802 
803 /*
804 ** Configuration settings for an individual database connection
805 */
806 int sqlite3_db_config(sqlite3 *db, int op, ...){
807   va_list ap;
808   int rc;
809   va_start(ap, op);
810   switch( op ){
811     case SQLITE_DBCONFIG_MAINDBNAME: {
812       /* IMP: R-06824-28531 */
813       /* IMP: R-36257-52125 */
814       db->aDb[0].zDbSName = va_arg(ap,char*);
815       rc = SQLITE_OK;
816       break;
817     }
818     case SQLITE_DBCONFIG_LOOKASIDE: {
819       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
820       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
821       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
822       rc = setupLookaside(db, pBuf, sz, cnt);
823       break;
824     }
825     default: {
826       static const struct {
827         int op;      /* The opcode */
828         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
829       } aFlagOp[] = {
830         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
831         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
832         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
833         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
834         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
835         { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
836         { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
837         { SQLITE_DBCONFIG_RESET_DATABASE,        SQLITE_ResetDatabase  },
838       };
839       unsigned int i;
840       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
841       for(i=0; i<ArraySize(aFlagOp); i++){
842         if( aFlagOp[i].op==op ){
843           int onoff = va_arg(ap, int);
844           int *pRes = va_arg(ap, int*);
845           u32 oldFlags = db->flags;
846           if( onoff>0 ){
847             db->flags |= aFlagOp[i].mask;
848           }else if( onoff==0 ){
849             db->flags &= ~aFlagOp[i].mask;
850           }
851           if( oldFlags!=db->flags ){
852             sqlite3ExpirePreparedStatements(db);
853           }
854           if( pRes ){
855             *pRes = (db->flags & aFlagOp[i].mask)!=0;
856           }
857           rc = SQLITE_OK;
858           break;
859         }
860       }
861       break;
862     }
863   }
864   va_end(ap);
865   return rc;
866 }
867 
868 
869 /*
870 ** Return true if the buffer z[0..n-1] contains all spaces.
871 */
872 static int allSpaces(const char *z, int n){
873   while( n>0 && z[n-1]==' ' ){ n--; }
874   return n==0;
875 }
876 
877 /*
878 ** This is the default collating function named "BINARY" which is always
879 ** available.
880 **
881 ** If the padFlag argument is not NULL then space padding at the end
882 ** of strings is ignored.  This implements the RTRIM collation.
883 */
884 static int binCollFunc(
885   void *padFlag,
886   int nKey1, const void *pKey1,
887   int nKey2, const void *pKey2
888 ){
889   int rc, n;
890   n = nKey1<nKey2 ? nKey1 : nKey2;
891   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
892   ** strings byte by byte using the memcmp() function from the standard C
893   ** library. */
894   assert( pKey1 && pKey2 );
895   rc = memcmp(pKey1, pKey2, n);
896   if( rc==0 ){
897     if( padFlag
898      && allSpaces(((char*)pKey1)+n, nKey1-n)
899      && allSpaces(((char*)pKey2)+n, nKey2-n)
900     ){
901       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
902       ** spaces at the end of either string do not change the result. In other
903       ** words, strings will compare equal to one another as long as they
904       ** differ only in the number of spaces at the end.
905       */
906     }else{
907       rc = nKey1 - nKey2;
908     }
909   }
910   return rc;
911 }
912 
913 /*
914 ** Another built-in collating sequence: NOCASE.
915 **
916 ** This collating sequence is intended to be used for "case independent
917 ** comparison". SQLite's knowledge of upper and lower case equivalents
918 ** extends only to the 26 characters used in the English language.
919 **
920 ** At the moment there is only a UTF-8 implementation.
921 */
922 static int nocaseCollatingFunc(
923   void *NotUsed,
924   int nKey1, const void *pKey1,
925   int nKey2, const void *pKey2
926 ){
927   int r = sqlite3StrNICmp(
928       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
929   UNUSED_PARAMETER(NotUsed);
930   if( 0==r ){
931     r = nKey1-nKey2;
932   }
933   return r;
934 }
935 
936 /*
937 ** Return the ROWID of the most recent insert
938 */
939 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
940 #ifdef SQLITE_ENABLE_API_ARMOR
941   if( !sqlite3SafetyCheckOk(db) ){
942     (void)SQLITE_MISUSE_BKPT;
943     return 0;
944   }
945 #endif
946   return db->lastRowid;
947 }
948 
949 /*
950 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
951 */
952 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
953 #ifdef SQLITE_ENABLE_API_ARMOR
954   if( !sqlite3SafetyCheckOk(db) ){
955     (void)SQLITE_MISUSE_BKPT;
956     return;
957   }
958 #endif
959   sqlite3_mutex_enter(db->mutex);
960   db->lastRowid = iRowid;
961   sqlite3_mutex_leave(db->mutex);
962 }
963 
964 /*
965 ** Return the number of changes in the most recent call to sqlite3_exec().
966 */
967 int sqlite3_changes(sqlite3 *db){
968 #ifdef SQLITE_ENABLE_API_ARMOR
969   if( !sqlite3SafetyCheckOk(db) ){
970     (void)SQLITE_MISUSE_BKPT;
971     return 0;
972   }
973 #endif
974   return db->nChange;
975 }
976 
977 /*
978 ** Return the number of changes since the database handle was opened.
979 */
980 int sqlite3_total_changes(sqlite3 *db){
981 #ifdef SQLITE_ENABLE_API_ARMOR
982   if( !sqlite3SafetyCheckOk(db) ){
983     (void)SQLITE_MISUSE_BKPT;
984     return 0;
985   }
986 #endif
987   return db->nTotalChange;
988 }
989 
990 /*
991 ** Close all open savepoints. This function only manipulates fields of the
992 ** database handle object, it does not close any savepoints that may be open
993 ** at the b-tree/pager level.
994 */
995 void sqlite3CloseSavepoints(sqlite3 *db){
996   while( db->pSavepoint ){
997     Savepoint *pTmp = db->pSavepoint;
998     db->pSavepoint = pTmp->pNext;
999     sqlite3DbFree(db, pTmp);
1000   }
1001   db->nSavepoint = 0;
1002   db->nStatement = 0;
1003   db->isTransactionSavepoint = 0;
1004 }
1005 
1006 /*
1007 ** Invoke the destructor function associated with FuncDef p, if any. Except,
1008 ** if this is not the last copy of the function, do not invoke it. Multiple
1009 ** copies of a single function are created when create_function() is called
1010 ** with SQLITE_ANY as the encoding.
1011 */
1012 static void functionDestroy(sqlite3 *db, FuncDef *p){
1013   FuncDestructor *pDestructor = p->u.pDestructor;
1014   if( pDestructor ){
1015     pDestructor->nRef--;
1016     if( pDestructor->nRef==0 ){
1017       pDestructor->xDestroy(pDestructor->pUserData);
1018       sqlite3DbFree(db, pDestructor);
1019     }
1020   }
1021 }
1022 
1023 /*
1024 ** Disconnect all sqlite3_vtab objects that belong to database connection
1025 ** db. This is called when db is being closed.
1026 */
1027 static void disconnectAllVtab(sqlite3 *db){
1028 #ifndef SQLITE_OMIT_VIRTUALTABLE
1029   int i;
1030   HashElem *p;
1031   sqlite3BtreeEnterAll(db);
1032   for(i=0; i<db->nDb; i++){
1033     Schema *pSchema = db->aDb[i].pSchema;
1034     if( db->aDb[i].pSchema ){
1035       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1036         Table *pTab = (Table *)sqliteHashData(p);
1037         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1038       }
1039     }
1040   }
1041   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1042     Module *pMod = (Module *)sqliteHashData(p);
1043     if( pMod->pEpoTab ){
1044       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1045     }
1046   }
1047   sqlite3VtabUnlockList(db);
1048   sqlite3BtreeLeaveAll(db);
1049 #else
1050   UNUSED_PARAMETER(db);
1051 #endif
1052 }
1053 
1054 /*
1055 ** Return TRUE if database connection db has unfinalized prepared
1056 ** statements or unfinished sqlite3_backup objects.
1057 */
1058 static int connectionIsBusy(sqlite3 *db){
1059   int j;
1060   assert( sqlite3_mutex_held(db->mutex) );
1061   if( db->pVdbe ) return 1;
1062   for(j=0; j<db->nDb; j++){
1063     Btree *pBt = db->aDb[j].pBt;
1064     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1065   }
1066   return 0;
1067 }
1068 
1069 /*
1070 ** Close an existing SQLite database
1071 */
1072 static int sqlite3Close(sqlite3 *db, int forceZombie){
1073   if( !db ){
1074     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1075     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1076     return SQLITE_OK;
1077   }
1078   if( !sqlite3SafetyCheckSickOrOk(db) ){
1079     return SQLITE_MISUSE_BKPT;
1080   }
1081   sqlite3_mutex_enter(db->mutex);
1082   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1083     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1084   }
1085 
1086   /* Force xDisconnect calls on all virtual tables */
1087   disconnectAllVtab(db);
1088 
1089   /* If a transaction is open, the disconnectAllVtab() call above
1090   ** will not have called the xDisconnect() method on any virtual
1091   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1092   ** call will do so. We need to do this before the check for active
1093   ** SQL statements below, as the v-table implementation may be storing
1094   ** some prepared statements internally.
1095   */
1096   sqlite3VtabRollback(db);
1097 
1098   /* Legacy behavior (sqlite3_close() behavior) is to return
1099   ** SQLITE_BUSY if the connection can not be closed immediately.
1100   */
1101   if( !forceZombie && connectionIsBusy(db) ){
1102     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1103        "statements or unfinished backups");
1104     sqlite3_mutex_leave(db->mutex);
1105     return SQLITE_BUSY;
1106   }
1107 
1108 #ifdef SQLITE_ENABLE_SQLLOG
1109   if( sqlite3GlobalConfig.xSqllog ){
1110     /* Closing the handle. Fourth parameter is passed the value 2. */
1111     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1112   }
1113 #endif
1114 
1115   /* Convert the connection into a zombie and then close it.
1116   */
1117   db->magic = SQLITE_MAGIC_ZOMBIE;
1118   sqlite3LeaveMutexAndCloseZombie(db);
1119   return SQLITE_OK;
1120 }
1121 
1122 /*
1123 ** Two variations on the public interface for closing a database
1124 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1125 ** leaves the connection option if there are unfinalized prepared
1126 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1127 ** version forces the connection to become a zombie if there are
1128 ** unclosed resources, and arranges for deallocation when the last
1129 ** prepare statement or sqlite3_backup closes.
1130 */
1131 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1132 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1133 
1134 
1135 /*
1136 ** Close the mutex on database connection db.
1137 **
1138 ** Furthermore, if database connection db is a zombie (meaning that there
1139 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1140 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1141 ** finished, then free all resources.
1142 */
1143 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1144   HashElem *i;                    /* Hash table iterator */
1145   int j;
1146 
1147   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1148   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1149   ** then just leave the mutex and return.
1150   */
1151   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1152     sqlite3_mutex_leave(db->mutex);
1153     return;
1154   }
1155 
1156   /* If we reach this point, it means that the database connection has
1157   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1158   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1159   ** go ahead and free all resources.
1160   */
1161 
1162   /* If a transaction is open, roll it back. This also ensures that if
1163   ** any database schemas have been modified by an uncommitted transaction
1164   ** they are reset. And that the required b-tree mutex is held to make
1165   ** the pager rollback and schema reset an atomic operation. */
1166   sqlite3RollbackAll(db, SQLITE_OK);
1167 
1168   /* Free any outstanding Savepoint structures. */
1169   sqlite3CloseSavepoints(db);
1170 
1171   /* Close all database connections */
1172   for(j=0; j<db->nDb; j++){
1173     struct Db *pDb = &db->aDb[j];
1174     if( pDb->pBt ){
1175       sqlite3BtreeClose(pDb->pBt);
1176       pDb->pBt = 0;
1177       if( j!=1 ){
1178         pDb->pSchema = 0;
1179       }
1180     }
1181   }
1182   /* Clear the TEMP schema separately and last */
1183   if( db->aDb[1].pSchema ){
1184     sqlite3SchemaClear(db->aDb[1].pSchema);
1185   }
1186   sqlite3VtabUnlockList(db);
1187 
1188   /* Free up the array of auxiliary databases */
1189   sqlite3CollapseDatabaseArray(db);
1190   assert( db->nDb<=2 );
1191   assert( db->aDb==db->aDbStatic );
1192 
1193   /* Tell the code in notify.c that the connection no longer holds any
1194   ** locks and does not require any further unlock-notify callbacks.
1195   */
1196   sqlite3ConnectionClosed(db);
1197 
1198   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1199     FuncDef *pNext, *p;
1200     p = sqliteHashData(i);
1201     do{
1202       functionDestroy(db, p);
1203       pNext = p->pNext;
1204       sqlite3DbFree(db, p);
1205       p = pNext;
1206     }while( p );
1207   }
1208   sqlite3HashClear(&db->aFunc);
1209   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1210     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1211     /* Invoke any destructors registered for collation sequence user data. */
1212     for(j=0; j<3; j++){
1213       if( pColl[j].xDel ){
1214         pColl[j].xDel(pColl[j].pUser);
1215       }
1216     }
1217     sqlite3DbFree(db, pColl);
1218   }
1219   sqlite3HashClear(&db->aCollSeq);
1220 #ifndef SQLITE_OMIT_VIRTUALTABLE
1221   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1222     Module *pMod = (Module *)sqliteHashData(i);
1223     if( pMod->xDestroy ){
1224       pMod->xDestroy(pMod->pAux);
1225     }
1226     sqlite3VtabEponymousTableClear(db, pMod);
1227     sqlite3DbFree(db, pMod);
1228   }
1229   sqlite3HashClear(&db->aModule);
1230 #endif
1231 
1232   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1233   sqlite3ValueFree(db->pErr);
1234   sqlite3CloseExtensions(db);
1235 #if SQLITE_USER_AUTHENTICATION
1236   sqlite3_free(db->auth.zAuthUser);
1237   sqlite3_free(db->auth.zAuthPW);
1238 #endif
1239 
1240   db->magic = SQLITE_MAGIC_ERROR;
1241 
1242   /* The temp-database schema is allocated differently from the other schema
1243   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1244   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1245   ** the same sqliteMalloc() as the one that allocates the database
1246   ** structure?
1247   */
1248   sqlite3DbFree(db, db->aDb[1].pSchema);
1249   sqlite3_mutex_leave(db->mutex);
1250   db->magic = SQLITE_MAGIC_CLOSED;
1251   sqlite3_mutex_free(db->mutex);
1252   assert( sqlite3LookasideUsed(db,0)==0 );
1253   if( db->lookaside.bMalloced ){
1254     sqlite3_free(db->lookaside.pStart);
1255   }
1256   sqlite3_free(db);
1257 }
1258 
1259 /*
1260 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1261 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1262 ** breaker") and made to return tripCode if there are any further
1263 ** attempts to use that cursor.  Read cursors remain open and valid
1264 ** but are "saved" in case the table pages are moved around.
1265 */
1266 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1267   int i;
1268   int inTrans = 0;
1269   int schemaChange;
1270   assert( sqlite3_mutex_held(db->mutex) );
1271   sqlite3BeginBenignMalloc();
1272 
1273   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1274   ** This is important in case the transaction being rolled back has
1275   ** modified the database schema. If the b-tree mutexes are not taken
1276   ** here, then another shared-cache connection might sneak in between
1277   ** the database rollback and schema reset, which can cause false
1278   ** corruption reports in some cases.  */
1279   sqlite3BtreeEnterAll(db);
1280   schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
1281 
1282   for(i=0; i<db->nDb; i++){
1283     Btree *p = db->aDb[i].pBt;
1284     if( p ){
1285       if( sqlite3BtreeIsInTrans(p) ){
1286         inTrans = 1;
1287       }
1288       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1289     }
1290   }
1291   sqlite3VtabRollback(db);
1292   sqlite3EndBenignMalloc();
1293 
1294   if( (db->mDbFlags&DBFLAG_SchemaChange)!=0 && db->init.busy==0 ){
1295     sqlite3ExpirePreparedStatements(db);
1296     sqlite3ResetAllSchemasOfConnection(db);
1297   }
1298   sqlite3BtreeLeaveAll(db);
1299 
1300   /* Any deferred constraint violations have now been resolved. */
1301   db->nDeferredCons = 0;
1302   db->nDeferredImmCons = 0;
1303   db->flags &= ~SQLITE_DeferFKs;
1304 
1305   /* If one has been configured, invoke the rollback-hook callback */
1306   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1307     db->xRollbackCallback(db->pRollbackArg);
1308   }
1309 }
1310 
1311 /*
1312 ** Return a static string containing the name corresponding to the error code
1313 ** specified in the argument.
1314 */
1315 #if defined(SQLITE_NEED_ERR_NAME)
1316 const char *sqlite3ErrName(int rc){
1317   const char *zName = 0;
1318   int i, origRc = rc;
1319   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1320     switch( rc ){
1321       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1322       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1323       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1324       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1325       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1326       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1327       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1328       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1329       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1330       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1331       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1332       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1333       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1334       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1335       case SQLITE_READONLY_CANTINIT:  zName = "SQLITE_READONLY_CANTINIT"; break;
1336       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1337       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1338       case SQLITE_READONLY_DIRECTORY: zName = "SQLITE_READONLY_DIRECTORY";break;
1339       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1340       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1341       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1342       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1343       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1344       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1345       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1346       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1347       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1348       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1349       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1350       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1351       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1352       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1353       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1354                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1355       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1356       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1357       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1358       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1359       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1360       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1361       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1362       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1363       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1364       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1365       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1366       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1367       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1368       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1369       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1370       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1371       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1372       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1373       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1374       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1375       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1376       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1377       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1378       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1379       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1380       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1381       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1382       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1383       case SQLITE_CONSTRAINT_FOREIGNKEY:
1384                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1385       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1386       case SQLITE_CONSTRAINT_PRIMARYKEY:
1387                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1388       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1389       case SQLITE_CONSTRAINT_COMMITHOOK:
1390                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1391       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1392       case SQLITE_CONSTRAINT_FUNCTION:
1393                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1394       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1395       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1396       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1397       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1398       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1399       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1400       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1401       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1402       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1403       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1404       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1405       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1406                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1407       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1408       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1409       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1410     }
1411   }
1412   if( zName==0 ){
1413     static char zBuf[50];
1414     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1415     zName = zBuf;
1416   }
1417   return zName;
1418 }
1419 #endif
1420 
1421 /*
1422 ** Return a static string that describes the kind of error specified in the
1423 ** argument.
1424 */
1425 const char *sqlite3ErrStr(int rc){
1426   static const char* const aMsg[] = {
1427     /* SQLITE_OK          */ "not an error",
1428     /* SQLITE_ERROR       */ "SQL logic error",
1429     /* SQLITE_INTERNAL    */ 0,
1430     /* SQLITE_PERM        */ "access permission denied",
1431     /* SQLITE_ABORT       */ "query aborted",
1432     /* SQLITE_BUSY        */ "database is locked",
1433     /* SQLITE_LOCKED      */ "database table is locked",
1434     /* SQLITE_NOMEM       */ "out of memory",
1435     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1436     /* SQLITE_INTERRUPT   */ "interrupted",
1437     /* SQLITE_IOERR       */ "disk I/O error",
1438     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1439     /* SQLITE_NOTFOUND    */ "unknown operation",
1440     /* SQLITE_FULL        */ "database or disk is full",
1441     /* SQLITE_CANTOPEN    */ "unable to open database file",
1442     /* SQLITE_PROTOCOL    */ "locking protocol",
1443     /* SQLITE_EMPTY       */ 0,
1444     /* SQLITE_SCHEMA      */ "database schema has changed",
1445     /* SQLITE_TOOBIG      */ "string or blob too big",
1446     /* SQLITE_CONSTRAINT  */ "constraint failed",
1447     /* SQLITE_MISMATCH    */ "datatype mismatch",
1448     /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
1449 #ifdef SQLITE_DISABLE_LFS
1450     /* SQLITE_NOLFS       */ "large file support is disabled",
1451 #else
1452     /* SQLITE_NOLFS       */ 0,
1453 #endif
1454     /* SQLITE_AUTH        */ "authorization denied",
1455     /* SQLITE_FORMAT      */ 0,
1456     /* SQLITE_RANGE       */ "column index out of range",
1457     /* SQLITE_NOTADB      */ "file is not a database",
1458     /* SQLITE_NOTICE      */ "notification message",
1459     /* SQLITE_WARNING     */ "warning message",
1460   };
1461   const char *zErr = "unknown error";
1462   switch( rc ){
1463     case SQLITE_ABORT_ROLLBACK: {
1464       zErr = "abort due to ROLLBACK";
1465       break;
1466     }
1467     case SQLITE_ROW: {
1468       zErr = "another row available";
1469       break;
1470     }
1471     case SQLITE_DONE: {
1472       zErr = "no more rows available";
1473       break;
1474     }
1475     default: {
1476       rc &= 0xff;
1477       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1478         zErr = aMsg[rc];
1479       }
1480       break;
1481     }
1482   }
1483   return zErr;
1484 }
1485 
1486 /*
1487 ** This routine implements a busy callback that sleeps and tries
1488 ** again until a timeout value is reached.  The timeout value is
1489 ** an integer number of milliseconds passed in as the first
1490 ** argument.
1491 **
1492 ** Return non-zero to retry the lock.  Return zero to stop trying
1493 ** and cause SQLite to return SQLITE_BUSY.
1494 */
1495 static int sqliteDefaultBusyCallback(
1496   void *ptr,               /* Database connection */
1497   int count,               /* Number of times table has been busy */
1498   sqlite3_file *pFile      /* The file on which the lock occurred */
1499 ){
1500 #if SQLITE_OS_WIN || HAVE_USLEEP
1501   /* This case is for systems that have support for sleeping for fractions of
1502   ** a second.  Examples:  All windows systems, unix systems with usleep() */
1503   static const u8 delays[] =
1504      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1505   static const u8 totals[] =
1506      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1507 # define NDELAY ArraySize(delays)
1508   sqlite3 *db = (sqlite3 *)ptr;
1509   int tmout = db->busyTimeout;
1510   int delay, prior;
1511 
1512 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
1513   if( sqlite3OsFileControl(pFile,SQLITE_FCNTL_LOCK_TIMEOUT,&tmout)==SQLITE_OK ){
1514     if( count ){
1515       tmout = 0;
1516       sqlite3OsFileControl(pFile, SQLITE_FCNTL_LOCK_TIMEOUT, &tmout);
1517       return 0;
1518     }else{
1519       return 1;
1520     }
1521   }
1522 #else
1523   UNUSED_PARAMETER(pFile);
1524 #endif
1525   assert( count>=0 );
1526   if( count < NDELAY ){
1527     delay = delays[count];
1528     prior = totals[count];
1529   }else{
1530     delay = delays[NDELAY-1];
1531     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1532   }
1533   if( prior + delay > tmout ){
1534     delay = tmout - prior;
1535     if( delay<=0 ) return 0;
1536   }
1537   sqlite3OsSleep(db->pVfs, delay*1000);
1538   return 1;
1539 #else
1540   /* This case for unix systems that lack usleep() support.  Sleeping
1541   ** must be done in increments of whole seconds */
1542   sqlite3 *db = (sqlite3 *)ptr;
1543   int tmout = ((sqlite3 *)ptr)->busyTimeout;
1544   UNUSED_PARAMETER(pFile);
1545   if( (count+1)*1000 > tmout ){
1546     return 0;
1547   }
1548   sqlite3OsSleep(db->pVfs, 1000000);
1549   return 1;
1550 #endif
1551 }
1552 
1553 /*
1554 ** Invoke the given busy handler.
1555 **
1556 ** This routine is called when an operation failed to acquire a
1557 ** lock on VFS file pFile.
1558 **
1559 ** If this routine returns non-zero, the lock is retried.  If it
1560 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1561 */
1562 int sqlite3InvokeBusyHandler(BusyHandler *p, sqlite3_file *pFile){
1563   int rc;
1564   if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
1565   if( p->bExtraFileArg ){
1566     /* Add an extra parameter with the pFile pointer to the end of the
1567     ** callback argument list */
1568     int (*xTra)(void*,int,sqlite3_file*);
1569     xTra = (int(*)(void*,int,sqlite3_file*))p->xBusyHandler;
1570     rc = xTra(p->pBusyArg, p->nBusy, pFile);
1571   }else{
1572     /* Legacy style busy handler callback */
1573     rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
1574   }
1575   if( rc==0 ){
1576     p->nBusy = -1;
1577   }else{
1578     p->nBusy++;
1579   }
1580   return rc;
1581 }
1582 
1583 /*
1584 ** This routine sets the busy callback for an Sqlite database to the
1585 ** given callback function with the given argument.
1586 */
1587 int sqlite3_busy_handler(
1588   sqlite3 *db,
1589   int (*xBusy)(void*,int),
1590   void *pArg
1591 ){
1592 #ifdef SQLITE_ENABLE_API_ARMOR
1593   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1594 #endif
1595   sqlite3_mutex_enter(db->mutex);
1596   db->busyHandler.xBusyHandler = xBusy;
1597   db->busyHandler.pBusyArg = pArg;
1598   db->busyHandler.nBusy = 0;
1599   db->busyHandler.bExtraFileArg = 0;
1600   db->busyTimeout = 0;
1601   sqlite3_mutex_leave(db->mutex);
1602   return SQLITE_OK;
1603 }
1604 
1605 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1606 /*
1607 ** This routine sets the progress callback for an Sqlite database to the
1608 ** given callback function with the given argument. The progress callback will
1609 ** be invoked every nOps opcodes.
1610 */
1611 void sqlite3_progress_handler(
1612   sqlite3 *db,
1613   int nOps,
1614   int (*xProgress)(void*),
1615   void *pArg
1616 ){
1617 #ifdef SQLITE_ENABLE_API_ARMOR
1618   if( !sqlite3SafetyCheckOk(db) ){
1619     (void)SQLITE_MISUSE_BKPT;
1620     return;
1621   }
1622 #endif
1623   sqlite3_mutex_enter(db->mutex);
1624   if( nOps>0 ){
1625     db->xProgress = xProgress;
1626     db->nProgressOps = (unsigned)nOps;
1627     db->pProgressArg = pArg;
1628   }else{
1629     db->xProgress = 0;
1630     db->nProgressOps = 0;
1631     db->pProgressArg = 0;
1632   }
1633   sqlite3_mutex_leave(db->mutex);
1634 }
1635 #endif
1636 
1637 
1638 /*
1639 ** This routine installs a default busy handler that waits for the
1640 ** specified number of milliseconds before returning 0.
1641 */
1642 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1643 #ifdef SQLITE_ENABLE_API_ARMOR
1644   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1645 #endif
1646   if( ms>0 ){
1647     sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
1648                              (void*)db);
1649     db->busyTimeout = ms;
1650     db->busyHandler.bExtraFileArg = 1;
1651   }else{
1652     sqlite3_busy_handler(db, 0, 0);
1653   }
1654   return SQLITE_OK;
1655 }
1656 
1657 /*
1658 ** Cause any pending operation to stop at its earliest opportunity.
1659 */
1660 void sqlite3_interrupt(sqlite3 *db){
1661 #ifdef SQLITE_ENABLE_API_ARMOR
1662   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1663     (void)SQLITE_MISUSE_BKPT;
1664     return;
1665   }
1666 #endif
1667   db->u1.isInterrupted = 1;
1668 }
1669 
1670 
1671 /*
1672 ** This function is exactly the same as sqlite3_create_function(), except
1673 ** that it is designed to be called by internal code. The difference is
1674 ** that if a malloc() fails in sqlite3_create_function(), an error code
1675 ** is returned and the mallocFailed flag cleared.
1676 */
1677 int sqlite3CreateFunc(
1678   sqlite3 *db,
1679   const char *zFunctionName,
1680   int nArg,
1681   int enc,
1682   void *pUserData,
1683   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1684   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1685   void (*xFinal)(sqlite3_context*),
1686   FuncDestructor *pDestructor
1687 ){
1688   FuncDef *p;
1689   int nName;
1690   int extraFlags;
1691 
1692   assert( sqlite3_mutex_held(db->mutex) );
1693   if( zFunctionName==0 ||
1694       (xSFunc && (xFinal || xStep)) ||
1695       (!xSFunc && (xFinal && !xStep)) ||
1696       (!xSFunc && (!xFinal && xStep)) ||
1697       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1698       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1699     return SQLITE_MISUSE_BKPT;
1700   }
1701 
1702   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1703   extraFlags = enc &  SQLITE_DETERMINISTIC;
1704   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1705 
1706 #ifndef SQLITE_OMIT_UTF16
1707   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1708   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1709   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1710   **
1711   ** If SQLITE_ANY is specified, add three versions of the function
1712   ** to the hash table.
1713   */
1714   if( enc==SQLITE_UTF16 ){
1715     enc = SQLITE_UTF16NATIVE;
1716   }else if( enc==SQLITE_ANY ){
1717     int rc;
1718     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1719          pUserData, xSFunc, xStep, xFinal, pDestructor);
1720     if( rc==SQLITE_OK ){
1721       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1722           pUserData, xSFunc, xStep, xFinal, pDestructor);
1723     }
1724     if( rc!=SQLITE_OK ){
1725       return rc;
1726     }
1727     enc = SQLITE_UTF16BE;
1728   }
1729 #else
1730   enc = SQLITE_UTF8;
1731 #endif
1732 
1733   /* Check if an existing function is being overridden or deleted. If so,
1734   ** and there are active VMs, then return SQLITE_BUSY. If a function
1735   ** is being overridden/deleted but there are no active VMs, allow the
1736   ** operation to continue but invalidate all precompiled statements.
1737   */
1738   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1739   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1740     if( db->nVdbeActive ){
1741       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1742         "unable to delete/modify user-function due to active statements");
1743       assert( !db->mallocFailed );
1744       return SQLITE_BUSY;
1745     }else{
1746       sqlite3ExpirePreparedStatements(db);
1747     }
1748   }
1749 
1750   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1751   assert(p || db->mallocFailed);
1752   if( !p ){
1753     return SQLITE_NOMEM_BKPT;
1754   }
1755 
1756   /* If an older version of the function with a configured destructor is
1757   ** being replaced invoke the destructor function here. */
1758   functionDestroy(db, p);
1759 
1760   if( pDestructor ){
1761     pDestructor->nRef++;
1762   }
1763   p->u.pDestructor = pDestructor;
1764   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1765   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1766   p->xSFunc = xSFunc ? xSFunc : xStep;
1767   p->xFinalize = xFinal;
1768   p->pUserData = pUserData;
1769   p->nArg = (u16)nArg;
1770   return SQLITE_OK;
1771 }
1772 
1773 /*
1774 ** Create new user functions.
1775 */
1776 int sqlite3_create_function(
1777   sqlite3 *db,
1778   const char *zFunc,
1779   int nArg,
1780   int enc,
1781   void *p,
1782   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1783   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1784   void (*xFinal)(sqlite3_context*)
1785 ){
1786   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1787                                     xFinal, 0);
1788 }
1789 
1790 int sqlite3_create_function_v2(
1791   sqlite3 *db,
1792   const char *zFunc,
1793   int nArg,
1794   int enc,
1795   void *p,
1796   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1797   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1798   void (*xFinal)(sqlite3_context*),
1799   void (*xDestroy)(void *)
1800 ){
1801   int rc = SQLITE_ERROR;
1802   FuncDestructor *pArg = 0;
1803 
1804 #ifdef SQLITE_ENABLE_API_ARMOR
1805   if( !sqlite3SafetyCheckOk(db) ){
1806     return SQLITE_MISUSE_BKPT;
1807   }
1808 #endif
1809   sqlite3_mutex_enter(db->mutex);
1810   if( xDestroy ){
1811     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1812     if( !pArg ){
1813       xDestroy(p);
1814       goto out;
1815     }
1816     pArg->xDestroy = xDestroy;
1817     pArg->pUserData = p;
1818   }
1819   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1820   if( pArg && pArg->nRef==0 ){
1821     assert( rc!=SQLITE_OK );
1822     xDestroy(p);
1823     sqlite3DbFree(db, pArg);
1824   }
1825 
1826  out:
1827   rc = sqlite3ApiExit(db, rc);
1828   sqlite3_mutex_leave(db->mutex);
1829   return rc;
1830 }
1831 
1832 #ifndef SQLITE_OMIT_UTF16
1833 int sqlite3_create_function16(
1834   sqlite3 *db,
1835   const void *zFunctionName,
1836   int nArg,
1837   int eTextRep,
1838   void *p,
1839   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1840   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1841   void (*xFinal)(sqlite3_context*)
1842 ){
1843   int rc;
1844   char *zFunc8;
1845 
1846 #ifdef SQLITE_ENABLE_API_ARMOR
1847   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1848 #endif
1849   sqlite3_mutex_enter(db->mutex);
1850   assert( !db->mallocFailed );
1851   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1852   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1853   sqlite3DbFree(db, zFunc8);
1854   rc = sqlite3ApiExit(db, rc);
1855   sqlite3_mutex_leave(db->mutex);
1856   return rc;
1857 }
1858 #endif
1859 
1860 
1861 /*
1862 ** Declare that a function has been overloaded by a virtual table.
1863 **
1864 ** If the function already exists as a regular global function, then
1865 ** this routine is a no-op.  If the function does not exist, then create
1866 ** a new one that always throws a run-time error.
1867 **
1868 ** When virtual tables intend to provide an overloaded function, they
1869 ** should call this routine to make sure the global function exists.
1870 ** A global function must exist in order for name resolution to work
1871 ** properly.
1872 */
1873 int sqlite3_overload_function(
1874   sqlite3 *db,
1875   const char *zName,
1876   int nArg
1877 ){
1878   int rc = SQLITE_OK;
1879 
1880 #ifdef SQLITE_ENABLE_API_ARMOR
1881   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1882     return SQLITE_MISUSE_BKPT;
1883   }
1884 #endif
1885   sqlite3_mutex_enter(db->mutex);
1886   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1887     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1888                            0, sqlite3InvalidFunction, 0, 0, 0);
1889   }
1890   rc = sqlite3ApiExit(db, rc);
1891   sqlite3_mutex_leave(db->mutex);
1892   return rc;
1893 }
1894 
1895 #ifndef SQLITE_OMIT_TRACE
1896 /*
1897 ** Register a trace function.  The pArg from the previously registered trace
1898 ** is returned.
1899 **
1900 ** A NULL trace function means that no tracing is executes.  A non-NULL
1901 ** trace is a pointer to a function that is invoked at the start of each
1902 ** SQL statement.
1903 */
1904 #ifndef SQLITE_OMIT_DEPRECATED
1905 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1906   void *pOld;
1907 
1908 #ifdef SQLITE_ENABLE_API_ARMOR
1909   if( !sqlite3SafetyCheckOk(db) ){
1910     (void)SQLITE_MISUSE_BKPT;
1911     return 0;
1912   }
1913 #endif
1914   sqlite3_mutex_enter(db->mutex);
1915   pOld = db->pTraceArg;
1916   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
1917   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
1918   db->pTraceArg = pArg;
1919   sqlite3_mutex_leave(db->mutex);
1920   return pOld;
1921 }
1922 #endif /* SQLITE_OMIT_DEPRECATED */
1923 
1924 /* Register a trace callback using the version-2 interface.
1925 */
1926 int sqlite3_trace_v2(
1927   sqlite3 *db,                               /* Trace this connection */
1928   unsigned mTrace,                           /* Mask of events to be traced */
1929   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
1930   void *pArg                                 /* Context */
1931 ){
1932 #ifdef SQLITE_ENABLE_API_ARMOR
1933   if( !sqlite3SafetyCheckOk(db) ){
1934     return SQLITE_MISUSE_BKPT;
1935   }
1936 #endif
1937   sqlite3_mutex_enter(db->mutex);
1938   if( mTrace==0 ) xTrace = 0;
1939   if( xTrace==0 ) mTrace = 0;
1940   db->mTrace = mTrace;
1941   db->xTrace = xTrace;
1942   db->pTraceArg = pArg;
1943   sqlite3_mutex_leave(db->mutex);
1944   return SQLITE_OK;
1945 }
1946 
1947 #ifndef SQLITE_OMIT_DEPRECATED
1948 /*
1949 ** Register a profile function.  The pArg from the previously registered
1950 ** profile function is returned.
1951 **
1952 ** A NULL profile function means that no profiling is executes.  A non-NULL
1953 ** profile is a pointer to a function that is invoked at the conclusion of
1954 ** each SQL statement that is run.
1955 */
1956 void *sqlite3_profile(
1957   sqlite3 *db,
1958   void (*xProfile)(void*,const char*,sqlite_uint64),
1959   void *pArg
1960 ){
1961   void *pOld;
1962 
1963 #ifdef SQLITE_ENABLE_API_ARMOR
1964   if( !sqlite3SafetyCheckOk(db) ){
1965     (void)SQLITE_MISUSE_BKPT;
1966     return 0;
1967   }
1968 #endif
1969   sqlite3_mutex_enter(db->mutex);
1970   pOld = db->pProfileArg;
1971   db->xProfile = xProfile;
1972   db->pProfileArg = pArg;
1973   sqlite3_mutex_leave(db->mutex);
1974   return pOld;
1975 }
1976 #endif /* SQLITE_OMIT_DEPRECATED */
1977 #endif /* SQLITE_OMIT_TRACE */
1978 
1979 /*
1980 ** Register a function to be invoked when a transaction commits.
1981 ** If the invoked function returns non-zero, then the commit becomes a
1982 ** rollback.
1983 */
1984 void *sqlite3_commit_hook(
1985   sqlite3 *db,              /* Attach the hook to this database */
1986   int (*xCallback)(void*),  /* Function to invoke on each commit */
1987   void *pArg                /* Argument to the function */
1988 ){
1989   void *pOld;
1990 
1991 #ifdef SQLITE_ENABLE_API_ARMOR
1992   if( !sqlite3SafetyCheckOk(db) ){
1993     (void)SQLITE_MISUSE_BKPT;
1994     return 0;
1995   }
1996 #endif
1997   sqlite3_mutex_enter(db->mutex);
1998   pOld = db->pCommitArg;
1999   db->xCommitCallback = xCallback;
2000   db->pCommitArg = pArg;
2001   sqlite3_mutex_leave(db->mutex);
2002   return pOld;
2003 }
2004 
2005 /*
2006 ** Register a callback to be invoked each time a row is updated,
2007 ** inserted or deleted using this database connection.
2008 */
2009 void *sqlite3_update_hook(
2010   sqlite3 *db,              /* Attach the hook to this database */
2011   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
2012   void *pArg                /* Argument to the function */
2013 ){
2014   void *pRet;
2015 
2016 #ifdef SQLITE_ENABLE_API_ARMOR
2017   if( !sqlite3SafetyCheckOk(db) ){
2018     (void)SQLITE_MISUSE_BKPT;
2019     return 0;
2020   }
2021 #endif
2022   sqlite3_mutex_enter(db->mutex);
2023   pRet = db->pUpdateArg;
2024   db->xUpdateCallback = xCallback;
2025   db->pUpdateArg = pArg;
2026   sqlite3_mutex_leave(db->mutex);
2027   return pRet;
2028 }
2029 
2030 /*
2031 ** Register a callback to be invoked each time a transaction is rolled
2032 ** back by this database connection.
2033 */
2034 void *sqlite3_rollback_hook(
2035   sqlite3 *db,              /* Attach the hook to this database */
2036   void (*xCallback)(void*), /* Callback function */
2037   void *pArg                /* Argument to the function */
2038 ){
2039   void *pRet;
2040 
2041 #ifdef SQLITE_ENABLE_API_ARMOR
2042   if( !sqlite3SafetyCheckOk(db) ){
2043     (void)SQLITE_MISUSE_BKPT;
2044     return 0;
2045   }
2046 #endif
2047   sqlite3_mutex_enter(db->mutex);
2048   pRet = db->pRollbackArg;
2049   db->xRollbackCallback = xCallback;
2050   db->pRollbackArg = pArg;
2051   sqlite3_mutex_leave(db->mutex);
2052   return pRet;
2053 }
2054 
2055 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2056 /*
2057 ** Register a callback to be invoked each time a row is updated,
2058 ** inserted or deleted using this database connection.
2059 */
2060 void *sqlite3_preupdate_hook(
2061   sqlite3 *db,              /* Attach the hook to this database */
2062   void(*xCallback)(         /* Callback function */
2063     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
2064   void *pArg                /* First callback argument */
2065 ){
2066   void *pRet;
2067   sqlite3_mutex_enter(db->mutex);
2068   pRet = db->pPreUpdateArg;
2069   db->xPreUpdateCallback = xCallback;
2070   db->pPreUpdateArg = pArg;
2071   sqlite3_mutex_leave(db->mutex);
2072   return pRet;
2073 }
2074 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2075 
2076 #ifndef SQLITE_OMIT_WAL
2077 /*
2078 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2079 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2080 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2081 ** wal_autocheckpoint()).
2082 */
2083 int sqlite3WalDefaultHook(
2084   void *pClientData,     /* Argument */
2085   sqlite3 *db,           /* Connection */
2086   const char *zDb,       /* Database */
2087   int nFrame             /* Size of WAL */
2088 ){
2089   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2090     sqlite3BeginBenignMalloc();
2091     sqlite3_wal_checkpoint(db, zDb);
2092     sqlite3EndBenignMalloc();
2093   }
2094   return SQLITE_OK;
2095 }
2096 #endif /* SQLITE_OMIT_WAL */
2097 
2098 /*
2099 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2100 ** a database after committing a transaction if there are nFrame or
2101 ** more frames in the log file. Passing zero or a negative value as the
2102 ** nFrame parameter disables automatic checkpoints entirely.
2103 **
2104 ** The callback registered by this function replaces any existing callback
2105 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2106 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2107 ** configured by this function.
2108 */
2109 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2110 #ifdef SQLITE_OMIT_WAL
2111   UNUSED_PARAMETER(db);
2112   UNUSED_PARAMETER(nFrame);
2113 #else
2114 #ifdef SQLITE_ENABLE_API_ARMOR
2115   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2116 #endif
2117   if( nFrame>0 ){
2118     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2119   }else{
2120     sqlite3_wal_hook(db, 0, 0);
2121   }
2122 #endif
2123   return SQLITE_OK;
2124 }
2125 
2126 /*
2127 ** Register a callback to be invoked each time a transaction is written
2128 ** into the write-ahead-log by this database connection.
2129 */
2130 void *sqlite3_wal_hook(
2131   sqlite3 *db,                    /* Attach the hook to this db handle */
2132   int(*xCallback)(void *, sqlite3*, const char*, int),
2133   void *pArg                      /* First argument passed to xCallback() */
2134 ){
2135 #ifndef SQLITE_OMIT_WAL
2136   void *pRet;
2137 #ifdef SQLITE_ENABLE_API_ARMOR
2138   if( !sqlite3SafetyCheckOk(db) ){
2139     (void)SQLITE_MISUSE_BKPT;
2140     return 0;
2141   }
2142 #endif
2143   sqlite3_mutex_enter(db->mutex);
2144   pRet = db->pWalArg;
2145   db->xWalCallback = xCallback;
2146   db->pWalArg = pArg;
2147   sqlite3_mutex_leave(db->mutex);
2148   return pRet;
2149 #else
2150   return 0;
2151 #endif
2152 }
2153 
2154 /*
2155 ** Checkpoint database zDb.
2156 */
2157 int sqlite3_wal_checkpoint_v2(
2158   sqlite3 *db,                    /* Database handle */
2159   const char *zDb,                /* Name of attached database (or NULL) */
2160   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2161   int *pnLog,                     /* OUT: Size of WAL log in frames */
2162   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2163 ){
2164 #ifdef SQLITE_OMIT_WAL
2165   return SQLITE_OK;
2166 #else
2167   int rc;                         /* Return code */
2168   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2169 
2170 #ifdef SQLITE_ENABLE_API_ARMOR
2171   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2172 #endif
2173 
2174   /* Initialize the output variables to -1 in case an error occurs. */
2175   if( pnLog ) *pnLog = -1;
2176   if( pnCkpt ) *pnCkpt = -1;
2177 
2178   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2179   assert( SQLITE_CHECKPOINT_FULL==1 );
2180   assert( SQLITE_CHECKPOINT_RESTART==2 );
2181   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2182   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2183     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2184     ** mode: */
2185     return SQLITE_MISUSE;
2186   }
2187 
2188   sqlite3_mutex_enter(db->mutex);
2189   if( zDb && zDb[0] ){
2190     iDb = sqlite3FindDbName(db, zDb);
2191   }
2192   if( iDb<0 ){
2193     rc = SQLITE_ERROR;
2194     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2195   }else{
2196     db->busyHandler.nBusy = 0;
2197     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2198     sqlite3Error(db, rc);
2199   }
2200   rc = sqlite3ApiExit(db, rc);
2201 
2202   /* If there are no active statements, clear the interrupt flag at this
2203   ** point.  */
2204   if( db->nVdbeActive==0 ){
2205     db->u1.isInterrupted = 0;
2206   }
2207 
2208   sqlite3_mutex_leave(db->mutex);
2209   return rc;
2210 #endif
2211 }
2212 
2213 
2214 /*
2215 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2216 ** to contains a zero-length string, all attached databases are
2217 ** checkpointed.
2218 */
2219 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2220   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2221   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2222   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2223 }
2224 
2225 #ifndef SQLITE_OMIT_WAL
2226 /*
2227 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2228 ** not currently open in WAL mode.
2229 **
2230 ** If a transaction is open on the database being checkpointed, this
2231 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2232 ** an error occurs while running the checkpoint, an SQLite error code is
2233 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2234 **
2235 ** The mutex on database handle db should be held by the caller. The mutex
2236 ** associated with the specific b-tree being checkpointed is taken by
2237 ** this function while the checkpoint is running.
2238 **
2239 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2240 ** checkpointed. If an error is encountered it is returned immediately -
2241 ** no attempt is made to checkpoint any remaining databases.
2242 **
2243 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
2244 ** or TRUNCATE.
2245 */
2246 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2247   int rc = SQLITE_OK;             /* Return code */
2248   int i;                          /* Used to iterate through attached dbs */
2249   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2250 
2251   assert( sqlite3_mutex_held(db->mutex) );
2252   assert( !pnLog || *pnLog==-1 );
2253   assert( !pnCkpt || *pnCkpt==-1 );
2254 
2255   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2256     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2257       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2258       pnLog = 0;
2259       pnCkpt = 0;
2260       if( rc==SQLITE_BUSY ){
2261         bBusy = 1;
2262         rc = SQLITE_OK;
2263       }
2264     }
2265   }
2266 
2267   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2268 }
2269 #endif /* SQLITE_OMIT_WAL */
2270 
2271 /*
2272 ** This function returns true if main-memory should be used instead of
2273 ** a temporary file for transient pager files and statement journals.
2274 ** The value returned depends on the value of db->temp_store (runtime
2275 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2276 ** following table describes the relationship between these two values
2277 ** and this functions return value.
2278 **
2279 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2280 **   -----------------     --------------     ------------------------------
2281 **   0                     any                file      (return 0)
2282 **   1                     1                  file      (return 0)
2283 **   1                     2                  memory    (return 1)
2284 **   1                     0                  file      (return 0)
2285 **   2                     1                  file      (return 0)
2286 **   2                     2                  memory    (return 1)
2287 **   2                     0                  memory    (return 1)
2288 **   3                     any                memory    (return 1)
2289 */
2290 int sqlite3TempInMemory(const sqlite3 *db){
2291 #if SQLITE_TEMP_STORE==1
2292   return ( db->temp_store==2 );
2293 #endif
2294 #if SQLITE_TEMP_STORE==2
2295   return ( db->temp_store!=1 );
2296 #endif
2297 #if SQLITE_TEMP_STORE==3
2298   UNUSED_PARAMETER(db);
2299   return 1;
2300 #endif
2301 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2302   UNUSED_PARAMETER(db);
2303   return 0;
2304 #endif
2305 }
2306 
2307 /*
2308 ** Return UTF-8 encoded English language explanation of the most recent
2309 ** error.
2310 */
2311 const char *sqlite3_errmsg(sqlite3 *db){
2312   const char *z;
2313   if( !db ){
2314     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2315   }
2316   if( !sqlite3SafetyCheckSickOrOk(db) ){
2317     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2318   }
2319   sqlite3_mutex_enter(db->mutex);
2320   if( db->mallocFailed ){
2321     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2322   }else{
2323     testcase( db->pErr==0 );
2324     z = (char*)sqlite3_value_text(db->pErr);
2325     assert( !db->mallocFailed );
2326     if( z==0 ){
2327       z = sqlite3ErrStr(db->errCode);
2328     }
2329   }
2330   sqlite3_mutex_leave(db->mutex);
2331   return z;
2332 }
2333 
2334 #ifndef SQLITE_OMIT_UTF16
2335 /*
2336 ** Return UTF-16 encoded English language explanation of the most recent
2337 ** error.
2338 */
2339 const void *sqlite3_errmsg16(sqlite3 *db){
2340   static const u16 outOfMem[] = {
2341     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2342   };
2343   static const u16 misuse[] = {
2344     'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
2345     'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
2346     'm', 'i', 's', 'u', 's', 'e', 0
2347   };
2348 
2349   const void *z;
2350   if( !db ){
2351     return (void *)outOfMem;
2352   }
2353   if( !sqlite3SafetyCheckSickOrOk(db) ){
2354     return (void *)misuse;
2355   }
2356   sqlite3_mutex_enter(db->mutex);
2357   if( db->mallocFailed ){
2358     z = (void *)outOfMem;
2359   }else{
2360     z = sqlite3_value_text16(db->pErr);
2361     if( z==0 ){
2362       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2363       z = sqlite3_value_text16(db->pErr);
2364     }
2365     /* A malloc() may have failed within the call to sqlite3_value_text16()
2366     ** above. If this is the case, then the db->mallocFailed flag needs to
2367     ** be cleared before returning. Do this directly, instead of via
2368     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2369     */
2370     sqlite3OomClear(db);
2371   }
2372   sqlite3_mutex_leave(db->mutex);
2373   return z;
2374 }
2375 #endif /* SQLITE_OMIT_UTF16 */
2376 
2377 /*
2378 ** Return the most recent error code generated by an SQLite routine. If NULL is
2379 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2380 */
2381 int sqlite3_errcode(sqlite3 *db){
2382   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2383     return SQLITE_MISUSE_BKPT;
2384   }
2385   if( !db || db->mallocFailed ){
2386     return SQLITE_NOMEM_BKPT;
2387   }
2388   return db->errCode & db->errMask;
2389 }
2390 int sqlite3_extended_errcode(sqlite3 *db){
2391   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2392     return SQLITE_MISUSE_BKPT;
2393   }
2394   if( !db || db->mallocFailed ){
2395     return SQLITE_NOMEM_BKPT;
2396   }
2397   return db->errCode;
2398 }
2399 int sqlite3_system_errno(sqlite3 *db){
2400   return db ? db->iSysErrno : 0;
2401 }
2402 
2403 /*
2404 ** Return a string that describes the kind of error specified in the
2405 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2406 ** function.
2407 */
2408 const char *sqlite3_errstr(int rc){
2409   return sqlite3ErrStr(rc);
2410 }
2411 
2412 /*
2413 ** Create a new collating function for database "db".  The name is zName
2414 ** and the encoding is enc.
2415 */
2416 static int createCollation(
2417   sqlite3* db,
2418   const char *zName,
2419   u8 enc,
2420   void* pCtx,
2421   int(*xCompare)(void*,int,const void*,int,const void*),
2422   void(*xDel)(void*)
2423 ){
2424   CollSeq *pColl;
2425   int enc2;
2426 
2427   assert( sqlite3_mutex_held(db->mutex) );
2428 
2429   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2430   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2431   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2432   */
2433   enc2 = enc;
2434   testcase( enc2==SQLITE_UTF16 );
2435   testcase( enc2==SQLITE_UTF16_ALIGNED );
2436   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2437     enc2 = SQLITE_UTF16NATIVE;
2438   }
2439   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2440     return SQLITE_MISUSE_BKPT;
2441   }
2442 
2443   /* Check if this call is removing or replacing an existing collation
2444   ** sequence. If so, and there are active VMs, return busy. If there
2445   ** are no active VMs, invalidate any pre-compiled statements.
2446   */
2447   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2448   if( pColl && pColl->xCmp ){
2449     if( db->nVdbeActive ){
2450       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2451         "unable to delete/modify collation sequence due to active statements");
2452       return SQLITE_BUSY;
2453     }
2454     sqlite3ExpirePreparedStatements(db);
2455 
2456     /* If collation sequence pColl was created directly by a call to
2457     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2458     ** then any copies made by synthCollSeq() need to be invalidated.
2459     ** Also, collation destructor - CollSeq.xDel() - function may need
2460     ** to be called.
2461     */
2462     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2463       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2464       int j;
2465       for(j=0; j<3; j++){
2466         CollSeq *p = &aColl[j];
2467         if( p->enc==pColl->enc ){
2468           if( p->xDel ){
2469             p->xDel(p->pUser);
2470           }
2471           p->xCmp = 0;
2472         }
2473       }
2474     }
2475   }
2476 
2477   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2478   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2479   pColl->xCmp = xCompare;
2480   pColl->pUser = pCtx;
2481   pColl->xDel = xDel;
2482   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2483   sqlite3Error(db, SQLITE_OK);
2484   return SQLITE_OK;
2485 }
2486 
2487 
2488 /*
2489 ** This array defines hard upper bounds on limit values.  The
2490 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2491 ** #defines in sqlite3.h.
2492 */
2493 static const int aHardLimit[] = {
2494   SQLITE_MAX_LENGTH,
2495   SQLITE_MAX_SQL_LENGTH,
2496   SQLITE_MAX_COLUMN,
2497   SQLITE_MAX_EXPR_DEPTH,
2498   SQLITE_MAX_COMPOUND_SELECT,
2499   SQLITE_MAX_VDBE_OP,
2500   SQLITE_MAX_FUNCTION_ARG,
2501   SQLITE_MAX_ATTACHED,
2502   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2503   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2504   SQLITE_MAX_TRIGGER_DEPTH,
2505   SQLITE_MAX_WORKER_THREADS,
2506 };
2507 
2508 /*
2509 ** Make sure the hard limits are set to reasonable values
2510 */
2511 #if SQLITE_MAX_LENGTH<100
2512 # error SQLITE_MAX_LENGTH must be at least 100
2513 #endif
2514 #if SQLITE_MAX_SQL_LENGTH<100
2515 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2516 #endif
2517 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2518 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2519 #endif
2520 #if SQLITE_MAX_COMPOUND_SELECT<2
2521 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2522 #endif
2523 #if SQLITE_MAX_VDBE_OP<40
2524 # error SQLITE_MAX_VDBE_OP must be at least 40
2525 #endif
2526 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2527 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2528 #endif
2529 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2530 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2531 #endif
2532 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2533 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2534 #endif
2535 #if SQLITE_MAX_COLUMN>32767
2536 # error SQLITE_MAX_COLUMN must not exceed 32767
2537 #endif
2538 #if SQLITE_MAX_TRIGGER_DEPTH<1
2539 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2540 #endif
2541 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2542 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2543 #endif
2544 
2545 
2546 /*
2547 ** Change the value of a limit.  Report the old value.
2548 ** If an invalid limit index is supplied, report -1.
2549 ** Make no changes but still report the old value if the
2550 ** new limit is negative.
2551 **
2552 ** A new lower limit does not shrink existing constructs.
2553 ** It merely prevents new constructs that exceed the limit
2554 ** from forming.
2555 */
2556 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2557   int oldLimit;
2558 
2559 #ifdef SQLITE_ENABLE_API_ARMOR
2560   if( !sqlite3SafetyCheckOk(db) ){
2561     (void)SQLITE_MISUSE_BKPT;
2562     return -1;
2563   }
2564 #endif
2565 
2566   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2567   ** there is a hard upper bound set at compile-time by a C preprocessor
2568   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2569   ** "_MAX_".)
2570   */
2571   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2572   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2573   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2574   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2575   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2576   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2577   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2578   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2579   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2580                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2581   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2582   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2583   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2584   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2585 
2586 
2587   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2588     return -1;
2589   }
2590   oldLimit = db->aLimit[limitId];
2591   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2592     if( newLimit>aHardLimit[limitId] ){
2593       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2594     }
2595     db->aLimit[limitId] = newLimit;
2596   }
2597   return oldLimit;                     /* IMP: R-53341-35419 */
2598 }
2599 
2600 /*
2601 ** This function is used to parse both URIs and non-URI filenames passed by the
2602 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2603 ** URIs specified as part of ATTACH statements.
2604 **
2605 ** The first argument to this function is the name of the VFS to use (or
2606 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2607 ** query parameter. The second argument contains the URI (or non-URI filename)
2608 ** itself. When this function is called the *pFlags variable should contain
2609 ** the default flags to open the database handle with. The value stored in
2610 ** *pFlags may be updated before returning if the URI filename contains
2611 ** "cache=xxx" or "mode=xxx" query parameters.
2612 **
2613 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2614 ** the VFS that should be used to open the database file. *pzFile is set to
2615 ** point to a buffer containing the name of the file to open. It is the
2616 ** responsibility of the caller to eventually call sqlite3_free() to release
2617 ** this buffer.
2618 **
2619 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2620 ** may be set to point to a buffer containing an English language error
2621 ** message. It is the responsibility of the caller to eventually release
2622 ** this buffer by calling sqlite3_free().
2623 */
2624 int sqlite3ParseUri(
2625   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2626   const char *zUri,               /* Nul-terminated URI to parse */
2627   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2628   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2629   char **pzFile,                  /* OUT: Filename component of URI */
2630   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2631 ){
2632   int rc = SQLITE_OK;
2633   unsigned int flags = *pFlags;
2634   const char *zVfs = zDefaultVfs;
2635   char *zFile;
2636   char c;
2637   int nUri = sqlite3Strlen30(zUri);
2638 
2639   assert( *pzErrMsg==0 );
2640 
2641   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2642             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2643    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2644   ){
2645     char *zOpt;
2646     int eState;                   /* Parser state when parsing URI */
2647     int iIn;                      /* Input character index */
2648     int iOut = 0;                 /* Output character index */
2649     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2650 
2651     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2652     ** method that there may be extra parameters following the file-name.  */
2653     flags |= SQLITE_OPEN_URI;
2654 
2655     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2656     zFile = sqlite3_malloc64(nByte);
2657     if( !zFile ) return SQLITE_NOMEM_BKPT;
2658 
2659     iIn = 5;
2660 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2661     if( strncmp(zUri+5, "///", 3)==0 ){
2662       iIn = 7;
2663       /* The following condition causes URIs with five leading / characters
2664       ** like file://///host/path to be converted into UNCs like //host/path.
2665       ** The correct URI for that UNC has only two or four leading / characters
2666       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2667       ** common error, we are told, so we handle it as a special case. */
2668       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2669     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2670       iIn = 16;
2671     }
2672 #else
2673     /* Discard the scheme and authority segments of the URI. */
2674     if( zUri[5]=='/' && zUri[6]=='/' ){
2675       iIn = 7;
2676       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2677       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2678         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2679             iIn-7, &zUri[7]);
2680         rc = SQLITE_ERROR;
2681         goto parse_uri_out;
2682       }
2683     }
2684 #endif
2685 
2686     /* Copy the filename and any query parameters into the zFile buffer.
2687     ** Decode %HH escape codes along the way.
2688     **
2689     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2690     ** on the parsing context. As follows:
2691     **
2692     **   0: Parsing file-name.
2693     **   1: Parsing name section of a name=value query parameter.
2694     **   2: Parsing value section of a name=value query parameter.
2695     */
2696     eState = 0;
2697     while( (c = zUri[iIn])!=0 && c!='#' ){
2698       iIn++;
2699       if( c=='%'
2700        && sqlite3Isxdigit(zUri[iIn])
2701        && sqlite3Isxdigit(zUri[iIn+1])
2702       ){
2703         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2704         octet += sqlite3HexToInt(zUri[iIn++]);
2705 
2706         assert( octet>=0 && octet<256 );
2707         if( octet==0 ){
2708 #ifndef SQLITE_ENABLE_URI_00_ERROR
2709           /* This branch is taken when "%00" appears within the URI. In this
2710           ** case we ignore all text in the remainder of the path, name or
2711           ** value currently being parsed. So ignore the current character
2712           ** and skip to the next "?", "=" or "&", as appropriate. */
2713           while( (c = zUri[iIn])!=0 && c!='#'
2714               && (eState!=0 || c!='?')
2715               && (eState!=1 || (c!='=' && c!='&'))
2716               && (eState!=2 || c!='&')
2717           ){
2718             iIn++;
2719           }
2720           continue;
2721 #else
2722           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2723           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2724           rc = SQLITE_ERROR;
2725           goto parse_uri_out;
2726 #endif
2727         }
2728         c = octet;
2729       }else if( eState==1 && (c=='&' || c=='=') ){
2730         if( zFile[iOut-1]==0 ){
2731           /* An empty option name. Ignore this option altogether. */
2732           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2733           continue;
2734         }
2735         if( c=='&' ){
2736           zFile[iOut++] = '\0';
2737         }else{
2738           eState = 2;
2739         }
2740         c = 0;
2741       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2742         c = 0;
2743         eState = 1;
2744       }
2745       zFile[iOut++] = c;
2746     }
2747     if( eState==1 ) zFile[iOut++] = '\0';
2748     zFile[iOut++] = '\0';
2749     zFile[iOut++] = '\0';
2750 
2751     /* Check if there were any options specified that should be interpreted
2752     ** here. Options that are interpreted here include "vfs" and those that
2753     ** correspond to flags that may be passed to the sqlite3_open_v2()
2754     ** method. */
2755     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2756     while( zOpt[0] ){
2757       int nOpt = sqlite3Strlen30(zOpt);
2758       char *zVal = &zOpt[nOpt+1];
2759       int nVal = sqlite3Strlen30(zVal);
2760 
2761       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2762         zVfs = zVal;
2763       }else{
2764         struct OpenMode {
2765           const char *z;
2766           int mode;
2767         } *aMode = 0;
2768         char *zModeType = 0;
2769         int mask = 0;
2770         int limit = 0;
2771 
2772         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2773           static struct OpenMode aCacheMode[] = {
2774             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2775             { "private", SQLITE_OPEN_PRIVATECACHE },
2776             { 0, 0 }
2777           };
2778 
2779           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2780           aMode = aCacheMode;
2781           limit = mask;
2782           zModeType = "cache";
2783         }
2784         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2785           static struct OpenMode aOpenMode[] = {
2786             { "ro",  SQLITE_OPEN_READONLY },
2787             { "rw",  SQLITE_OPEN_READWRITE },
2788             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2789             { "memory", SQLITE_OPEN_MEMORY },
2790             { 0, 0 }
2791           };
2792 
2793           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2794                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2795           aMode = aOpenMode;
2796           limit = mask & flags;
2797           zModeType = "access";
2798         }
2799 
2800         if( aMode ){
2801           int i;
2802           int mode = 0;
2803           for(i=0; aMode[i].z; i++){
2804             const char *z = aMode[i].z;
2805             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2806               mode = aMode[i].mode;
2807               break;
2808             }
2809           }
2810           if( mode==0 ){
2811             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2812             rc = SQLITE_ERROR;
2813             goto parse_uri_out;
2814           }
2815           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2816             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2817                                         zModeType, zVal);
2818             rc = SQLITE_PERM;
2819             goto parse_uri_out;
2820           }
2821           flags = (flags & ~mask) | mode;
2822         }
2823       }
2824 
2825       zOpt = &zVal[nVal+1];
2826     }
2827 
2828   }else{
2829     zFile = sqlite3_malloc64(nUri+2);
2830     if( !zFile ) return SQLITE_NOMEM_BKPT;
2831     if( nUri ){
2832       memcpy(zFile, zUri, nUri);
2833     }
2834     zFile[nUri] = '\0';
2835     zFile[nUri+1] = '\0';
2836     flags &= ~SQLITE_OPEN_URI;
2837   }
2838 
2839   *ppVfs = sqlite3_vfs_find(zVfs);
2840   if( *ppVfs==0 ){
2841     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2842     rc = SQLITE_ERROR;
2843   }
2844  parse_uri_out:
2845   if( rc!=SQLITE_OK ){
2846     sqlite3_free(zFile);
2847     zFile = 0;
2848   }
2849   *pFlags = flags;
2850   *pzFile = zFile;
2851   return rc;
2852 }
2853 
2854 
2855 /*
2856 ** This routine does the work of opening a database on behalf of
2857 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2858 ** is UTF-8 encoded.
2859 */
2860 static int openDatabase(
2861   const char *zFilename, /* Database filename UTF-8 encoded */
2862   sqlite3 **ppDb,        /* OUT: Returned database handle */
2863   unsigned int flags,    /* Operational flags */
2864   const char *zVfs       /* Name of the VFS to use */
2865 ){
2866   sqlite3 *db;                    /* Store allocated handle here */
2867   int rc;                         /* Return code */
2868   int isThreadsafe;               /* True for threadsafe connections */
2869   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2870   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2871 
2872 #ifdef SQLITE_ENABLE_API_ARMOR
2873   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2874 #endif
2875   *ppDb = 0;
2876 #ifndef SQLITE_OMIT_AUTOINIT
2877   rc = sqlite3_initialize();
2878   if( rc ) return rc;
2879 #endif
2880 
2881   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2882     isThreadsafe = 0;
2883   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2884     isThreadsafe = 0;
2885   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2886     isThreadsafe = 1;
2887   }else{
2888     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2889   }
2890 
2891   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2892     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2893   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2894     flags |= SQLITE_OPEN_SHAREDCACHE;
2895   }
2896 
2897   /* Remove harmful bits from the flags parameter
2898   **
2899   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2900   ** dealt with in the previous code block.  Besides these, the only
2901   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2902   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2903   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2904   ** off all other flags.
2905   */
2906   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2907                SQLITE_OPEN_EXCLUSIVE |
2908                SQLITE_OPEN_MAIN_DB |
2909                SQLITE_OPEN_TEMP_DB |
2910                SQLITE_OPEN_TRANSIENT_DB |
2911                SQLITE_OPEN_MAIN_JOURNAL |
2912                SQLITE_OPEN_TEMP_JOURNAL |
2913                SQLITE_OPEN_SUBJOURNAL |
2914                SQLITE_OPEN_MASTER_JOURNAL |
2915                SQLITE_OPEN_NOMUTEX |
2916                SQLITE_OPEN_FULLMUTEX |
2917                SQLITE_OPEN_WAL
2918              );
2919 
2920   /* Allocate the sqlite data structure */
2921   db = sqlite3MallocZero( sizeof(sqlite3) );
2922   if( db==0 ) goto opendb_out;
2923   if( isThreadsafe
2924 #ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
2925    || sqlite3GlobalConfig.bCoreMutex
2926 #endif
2927   ){
2928     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2929     if( db->mutex==0 ){
2930       sqlite3_free(db);
2931       db = 0;
2932       goto opendb_out;
2933     }
2934     if( isThreadsafe==0 ){
2935       sqlite3MutexWarnOnContention(db->mutex);
2936     }
2937   }
2938   sqlite3_mutex_enter(db->mutex);
2939   db->errMask = 0xff;
2940   db->nDb = 2;
2941   db->magic = SQLITE_MAGIC_BUSY;
2942   db->aDb = db->aDbStatic;
2943 
2944   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2945   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2946   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2947   db->autoCommit = 1;
2948   db->nextAutovac = -1;
2949   db->szMmap = sqlite3GlobalConfig.szMmap;
2950   db->nextPagesize = 0;
2951   db->nMaxSorterMmap = 0x7FFFFFFF;
2952   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2953 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2954                  | SQLITE_AutoIndex
2955 #endif
2956 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2957                  | SQLITE_CkptFullFSync
2958 #endif
2959 #if SQLITE_DEFAULT_FILE_FORMAT<4
2960                  | SQLITE_LegacyFileFmt
2961 #endif
2962 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2963                  | SQLITE_LoadExtension
2964 #endif
2965 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2966                  | SQLITE_RecTriggers
2967 #endif
2968 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2969                  | SQLITE_ForeignKeys
2970 #endif
2971 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2972                  | SQLITE_ReverseOrder
2973 #endif
2974 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2975                  | SQLITE_CellSizeCk
2976 #endif
2977 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
2978                  | SQLITE_Fts3Tokenizer
2979 #endif
2980 #if defined(SQLITE_ENABLE_QPSG)
2981                  | SQLITE_EnableQPSG
2982 #endif
2983       ;
2984   sqlite3HashInit(&db->aCollSeq);
2985 #ifndef SQLITE_OMIT_VIRTUALTABLE
2986   sqlite3HashInit(&db->aModule);
2987 #endif
2988 
2989   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2990   ** and UTF-16, so add a version for each to avoid any unnecessary
2991   ** conversions. The only error that can occur here is a malloc() failure.
2992   **
2993   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2994   ** functions:
2995   */
2996   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2997   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2998   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2999   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
3000   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
3001   if( db->mallocFailed ){
3002     goto opendb_out;
3003   }
3004   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
3005   ** strings is BINARY.
3006   */
3007   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
3008   assert( db->pDfltColl!=0 );
3009 
3010   /* Parse the filename/URI argument
3011   **
3012   ** Only allow sensible combinations of bits in the flags argument.
3013   ** Throw an error if any non-sense combination is used.  If we
3014   ** do not block illegal combinations here, it could trigger
3015   ** assert() statements in deeper layers.  Sensible combinations
3016   ** are:
3017   **
3018   **  1:  SQLITE_OPEN_READONLY
3019   **  2:  SQLITE_OPEN_READWRITE
3020   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
3021   */
3022   db->openFlags = flags;
3023   assert( SQLITE_OPEN_READONLY  == 0x01 );
3024   assert( SQLITE_OPEN_READWRITE == 0x02 );
3025   assert( SQLITE_OPEN_CREATE    == 0x04 );
3026   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
3027   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
3028   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
3029   if( ((1<<(flags&7)) & 0x46)==0 ){
3030     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
3031   }else{
3032     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
3033   }
3034   if( rc!=SQLITE_OK ){
3035     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
3036     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
3037     sqlite3_free(zErrMsg);
3038     goto opendb_out;
3039   }
3040 
3041   /* Open the backend database driver */
3042   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
3043                         flags | SQLITE_OPEN_MAIN_DB);
3044   if( rc!=SQLITE_OK ){
3045     if( rc==SQLITE_IOERR_NOMEM ){
3046       rc = SQLITE_NOMEM_BKPT;
3047     }
3048     sqlite3Error(db, rc);
3049     goto opendb_out;
3050   }
3051   sqlite3BtreeEnter(db->aDb[0].pBt);
3052   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
3053   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
3054   sqlite3BtreeLeave(db->aDb[0].pBt);
3055   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
3056 
3057   /* The default safety_level for the main database is FULL; for the temp
3058   ** database it is OFF. This matches the pager layer defaults.
3059   */
3060   db->aDb[0].zDbSName = "main";
3061   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
3062   db->aDb[1].zDbSName = "temp";
3063   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
3064 
3065   db->magic = SQLITE_MAGIC_OPEN;
3066   if( db->mallocFailed ){
3067     goto opendb_out;
3068   }
3069 
3070   /* Register all built-in functions, but do not attempt to read the
3071   ** database schema yet. This is delayed until the first time the database
3072   ** is accessed.
3073   */
3074   sqlite3Error(db, SQLITE_OK);
3075   sqlite3RegisterPerConnectionBuiltinFunctions(db);
3076   rc = sqlite3_errcode(db);
3077 
3078 #ifdef SQLITE_ENABLE_FTS5
3079   /* Register any built-in FTS5 module before loading the automatic
3080   ** extensions. This allows automatic extensions to register FTS5
3081   ** tokenizers and auxiliary functions.  */
3082   if( !db->mallocFailed && rc==SQLITE_OK ){
3083     rc = sqlite3Fts5Init(db);
3084   }
3085 #endif
3086 
3087   /* Load automatic extensions - extensions that have been registered
3088   ** using the sqlite3_automatic_extension() API.
3089   */
3090   if( rc==SQLITE_OK ){
3091     sqlite3AutoLoadExtensions(db);
3092     rc = sqlite3_errcode(db);
3093     if( rc!=SQLITE_OK ){
3094       goto opendb_out;
3095     }
3096   }
3097 
3098 #ifdef SQLITE_ENABLE_FTS1
3099   if( !db->mallocFailed ){
3100     extern int sqlite3Fts1Init(sqlite3*);
3101     rc = sqlite3Fts1Init(db);
3102   }
3103 #endif
3104 
3105 #ifdef SQLITE_ENABLE_FTS2
3106   if( !db->mallocFailed && rc==SQLITE_OK ){
3107     extern int sqlite3Fts2Init(sqlite3*);
3108     rc = sqlite3Fts2Init(db);
3109   }
3110 #endif
3111 
3112 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3113   if( !db->mallocFailed && rc==SQLITE_OK ){
3114     rc = sqlite3Fts3Init(db);
3115   }
3116 #endif
3117 
3118 #if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
3119   if( !db->mallocFailed && rc==SQLITE_OK ){
3120     rc = sqlite3IcuInit(db);
3121   }
3122 #endif
3123 
3124 #ifdef SQLITE_ENABLE_RTREE
3125   if( !db->mallocFailed && rc==SQLITE_OK){
3126     rc = sqlite3RtreeInit(db);
3127   }
3128 #endif
3129 
3130 #ifdef SQLITE_ENABLE_DBPAGE_VTAB
3131   if( !db->mallocFailed && rc==SQLITE_OK){
3132     rc = sqlite3DbpageRegister(db);
3133   }
3134 #endif
3135 
3136 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3137   if( !db->mallocFailed && rc==SQLITE_OK){
3138     rc = sqlite3DbstatRegister(db);
3139   }
3140 #endif
3141 
3142 #ifdef SQLITE_ENABLE_JSON1
3143   if( !db->mallocFailed && rc==SQLITE_OK){
3144     rc = sqlite3Json1Init(db);
3145   }
3146 #endif
3147 
3148 #ifdef SQLITE_ENABLE_STMTVTAB
3149   if( !db->mallocFailed && rc==SQLITE_OK){
3150     rc = sqlite3StmtVtabInit(db);
3151   }
3152 #endif
3153 
3154   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3155   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3156   ** mode.  Doing nothing at all also makes NORMAL the default.
3157   */
3158 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3159   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3160   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3161                           SQLITE_DEFAULT_LOCKING_MODE);
3162 #endif
3163 
3164   if( rc ) sqlite3Error(db, rc);
3165 
3166   /* Enable the lookaside-malloc subsystem */
3167   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3168                         sqlite3GlobalConfig.nLookaside);
3169 
3170   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3171 
3172 opendb_out:
3173   if( db ){
3174     assert( db->mutex!=0 || isThreadsafe==0
3175            || sqlite3GlobalConfig.bFullMutex==0 );
3176     sqlite3_mutex_leave(db->mutex);
3177   }
3178   rc = sqlite3_errcode(db);
3179   assert( db!=0 || rc==SQLITE_NOMEM );
3180   if( rc==SQLITE_NOMEM ){
3181     sqlite3_close(db);
3182     db = 0;
3183   }else if( rc!=SQLITE_OK ){
3184     db->magic = SQLITE_MAGIC_SICK;
3185   }
3186   *ppDb = db;
3187 #ifdef SQLITE_ENABLE_SQLLOG
3188   if( sqlite3GlobalConfig.xSqllog ){
3189     /* Opening a db handle. Fourth parameter is passed 0. */
3190     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3191     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3192   }
3193 #endif
3194 #if defined(SQLITE_HAS_CODEC)
3195   if( rc==SQLITE_OK ){
3196     const char *zKey;
3197     if( (zKey = sqlite3_uri_parameter(zOpen, "hexkey"))!=0 && zKey[0] ){
3198       u8 iByte;
3199       int i;
3200       char zDecoded[40];
3201       for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
3202         iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
3203         if( (i&1)!=0 ) zDecoded[i/2] = iByte;
3204       }
3205       sqlite3_key_v2(db, 0, zDecoded, i/2);
3206     }else if( (zKey = sqlite3_uri_parameter(zOpen, "key"))!=0 ){
3207       sqlite3_key_v2(db, 0, zKey, sqlite3Strlen30(zKey));
3208     }
3209   }
3210 #endif
3211   sqlite3_free(zOpen);
3212   return rc & 0xff;
3213 }
3214 
3215 /*
3216 ** Open a new database handle.
3217 */
3218 int sqlite3_open(
3219   const char *zFilename,
3220   sqlite3 **ppDb
3221 ){
3222   return openDatabase(zFilename, ppDb,
3223                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3224 }
3225 int sqlite3_open_v2(
3226   const char *filename,   /* Database filename (UTF-8) */
3227   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3228   int flags,              /* Flags */
3229   const char *zVfs        /* Name of VFS module to use */
3230 ){
3231   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3232 }
3233 
3234 #ifndef SQLITE_OMIT_UTF16
3235 /*
3236 ** Open a new database handle.
3237 */
3238 int sqlite3_open16(
3239   const void *zFilename,
3240   sqlite3 **ppDb
3241 ){
3242   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3243   sqlite3_value *pVal;
3244   int rc;
3245 
3246 #ifdef SQLITE_ENABLE_API_ARMOR
3247   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3248 #endif
3249   *ppDb = 0;
3250 #ifndef SQLITE_OMIT_AUTOINIT
3251   rc = sqlite3_initialize();
3252   if( rc ) return rc;
3253 #endif
3254   if( zFilename==0 ) zFilename = "\000\000";
3255   pVal = sqlite3ValueNew(0);
3256   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3257   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3258   if( zFilename8 ){
3259     rc = openDatabase(zFilename8, ppDb,
3260                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3261     assert( *ppDb || rc==SQLITE_NOMEM );
3262     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3263       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3264     }
3265   }else{
3266     rc = SQLITE_NOMEM_BKPT;
3267   }
3268   sqlite3ValueFree(pVal);
3269 
3270   return rc & 0xff;
3271 }
3272 #endif /* SQLITE_OMIT_UTF16 */
3273 
3274 /*
3275 ** Register a new collation sequence with the database handle db.
3276 */
3277 int sqlite3_create_collation(
3278   sqlite3* db,
3279   const char *zName,
3280   int enc,
3281   void* pCtx,
3282   int(*xCompare)(void*,int,const void*,int,const void*)
3283 ){
3284   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3285 }
3286 
3287 /*
3288 ** Register a new collation sequence with the database handle db.
3289 */
3290 int sqlite3_create_collation_v2(
3291   sqlite3* db,
3292   const char *zName,
3293   int enc,
3294   void* pCtx,
3295   int(*xCompare)(void*,int,const void*,int,const void*),
3296   void(*xDel)(void*)
3297 ){
3298   int rc;
3299 
3300 #ifdef SQLITE_ENABLE_API_ARMOR
3301   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3302 #endif
3303   sqlite3_mutex_enter(db->mutex);
3304   assert( !db->mallocFailed );
3305   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3306   rc = sqlite3ApiExit(db, rc);
3307   sqlite3_mutex_leave(db->mutex);
3308   return rc;
3309 }
3310 
3311 #ifndef SQLITE_OMIT_UTF16
3312 /*
3313 ** Register a new collation sequence with the database handle db.
3314 */
3315 int sqlite3_create_collation16(
3316   sqlite3* db,
3317   const void *zName,
3318   int enc,
3319   void* pCtx,
3320   int(*xCompare)(void*,int,const void*,int,const void*)
3321 ){
3322   int rc = SQLITE_OK;
3323   char *zName8;
3324 
3325 #ifdef SQLITE_ENABLE_API_ARMOR
3326   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3327 #endif
3328   sqlite3_mutex_enter(db->mutex);
3329   assert( !db->mallocFailed );
3330   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3331   if( zName8 ){
3332     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3333     sqlite3DbFree(db, zName8);
3334   }
3335   rc = sqlite3ApiExit(db, rc);
3336   sqlite3_mutex_leave(db->mutex);
3337   return rc;
3338 }
3339 #endif /* SQLITE_OMIT_UTF16 */
3340 
3341 /*
3342 ** Register a collation sequence factory callback with the database handle
3343 ** db. Replace any previously installed collation sequence factory.
3344 */
3345 int sqlite3_collation_needed(
3346   sqlite3 *db,
3347   void *pCollNeededArg,
3348   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3349 ){
3350 #ifdef SQLITE_ENABLE_API_ARMOR
3351   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3352 #endif
3353   sqlite3_mutex_enter(db->mutex);
3354   db->xCollNeeded = xCollNeeded;
3355   db->xCollNeeded16 = 0;
3356   db->pCollNeededArg = pCollNeededArg;
3357   sqlite3_mutex_leave(db->mutex);
3358   return SQLITE_OK;
3359 }
3360 
3361 #ifndef SQLITE_OMIT_UTF16
3362 /*
3363 ** Register a collation sequence factory callback with the database handle
3364 ** db. Replace any previously installed collation sequence factory.
3365 */
3366 int sqlite3_collation_needed16(
3367   sqlite3 *db,
3368   void *pCollNeededArg,
3369   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3370 ){
3371 #ifdef SQLITE_ENABLE_API_ARMOR
3372   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3373 #endif
3374   sqlite3_mutex_enter(db->mutex);
3375   db->xCollNeeded = 0;
3376   db->xCollNeeded16 = xCollNeeded16;
3377   db->pCollNeededArg = pCollNeededArg;
3378   sqlite3_mutex_leave(db->mutex);
3379   return SQLITE_OK;
3380 }
3381 #endif /* SQLITE_OMIT_UTF16 */
3382 
3383 #ifndef SQLITE_OMIT_DEPRECATED
3384 /*
3385 ** This function is now an anachronism. It used to be used to recover from a
3386 ** malloc() failure, but SQLite now does this automatically.
3387 */
3388 int sqlite3_global_recover(void){
3389   return SQLITE_OK;
3390 }
3391 #endif
3392 
3393 /*
3394 ** Test to see whether or not the database connection is in autocommit
3395 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3396 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3397 ** by the next COMMIT or ROLLBACK.
3398 */
3399 int sqlite3_get_autocommit(sqlite3 *db){
3400 #ifdef SQLITE_ENABLE_API_ARMOR
3401   if( !sqlite3SafetyCheckOk(db) ){
3402     (void)SQLITE_MISUSE_BKPT;
3403     return 0;
3404   }
3405 #endif
3406   return db->autoCommit;
3407 }
3408 
3409 /*
3410 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3411 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3412 ** constants.  They serve two purposes:
3413 **
3414 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3415 **       to detect when version error conditions occurs.
3416 **
3417 **   2.  Invoke sqlite3_log() to provide the source code location where
3418 **       a low-level error is first detected.
3419 */
3420 int sqlite3ReportError(int iErr, int lineno, const char *zType){
3421   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3422               zType, lineno, 20+sqlite3_sourceid());
3423   return iErr;
3424 }
3425 int sqlite3CorruptError(int lineno){
3426   testcase( sqlite3GlobalConfig.xLog!=0 );
3427   return sqlite3ReportError(SQLITE_CORRUPT, lineno, "database corruption");
3428 }
3429 int sqlite3MisuseError(int lineno){
3430   testcase( sqlite3GlobalConfig.xLog!=0 );
3431   return sqlite3ReportError(SQLITE_MISUSE, lineno, "misuse");
3432 }
3433 int sqlite3CantopenError(int lineno){
3434   testcase( sqlite3GlobalConfig.xLog!=0 );
3435   return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3436 }
3437 #ifdef SQLITE_DEBUG
3438 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3439   char zMsg[100];
3440   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3441   testcase( sqlite3GlobalConfig.xLog!=0 );
3442   return sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
3443 }
3444 int sqlite3NomemError(int lineno){
3445   testcase( sqlite3GlobalConfig.xLog!=0 );
3446   return sqlite3ReportError(SQLITE_NOMEM, lineno, "OOM");
3447 }
3448 int sqlite3IoerrnomemError(int lineno){
3449   testcase( sqlite3GlobalConfig.xLog!=0 );
3450   return sqlite3ReportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3451 }
3452 #endif
3453 
3454 #ifndef SQLITE_OMIT_DEPRECATED
3455 /*
3456 ** This is a convenience routine that makes sure that all thread-specific
3457 ** data for this thread has been deallocated.
3458 **
3459 ** SQLite no longer uses thread-specific data so this routine is now a
3460 ** no-op.  It is retained for historical compatibility.
3461 */
3462 void sqlite3_thread_cleanup(void){
3463 }
3464 #endif
3465 
3466 /*
3467 ** Return meta information about a specific column of a database table.
3468 ** See comment in sqlite3.h (sqlite.h.in) for details.
3469 */
3470 int sqlite3_table_column_metadata(
3471   sqlite3 *db,                /* Connection handle */
3472   const char *zDbName,        /* Database name or NULL */
3473   const char *zTableName,     /* Table name */
3474   const char *zColumnName,    /* Column name */
3475   char const **pzDataType,    /* OUTPUT: Declared data type */
3476   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3477   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3478   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3479   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3480 ){
3481   int rc;
3482   char *zErrMsg = 0;
3483   Table *pTab = 0;
3484   Column *pCol = 0;
3485   int iCol = 0;
3486   char const *zDataType = 0;
3487   char const *zCollSeq = 0;
3488   int notnull = 0;
3489   int primarykey = 0;
3490   int autoinc = 0;
3491 
3492 
3493 #ifdef SQLITE_ENABLE_API_ARMOR
3494   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3495     return SQLITE_MISUSE_BKPT;
3496   }
3497 #endif
3498 
3499   /* Ensure the database schema has been loaded */
3500   sqlite3_mutex_enter(db->mutex);
3501   sqlite3BtreeEnterAll(db);
3502   rc = sqlite3Init(db, &zErrMsg);
3503   if( SQLITE_OK!=rc ){
3504     goto error_out;
3505   }
3506 
3507   /* Locate the table in question */
3508   pTab = sqlite3FindTable(db, zTableName, zDbName);
3509   if( !pTab || pTab->pSelect ){
3510     pTab = 0;
3511     goto error_out;
3512   }
3513 
3514   /* Find the column for which info is requested */
3515   if( zColumnName==0 ){
3516     /* Query for existance of table only */
3517   }else{
3518     for(iCol=0; iCol<pTab->nCol; iCol++){
3519       pCol = &pTab->aCol[iCol];
3520       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3521         break;
3522       }
3523     }
3524     if( iCol==pTab->nCol ){
3525       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3526         iCol = pTab->iPKey;
3527         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3528       }else{
3529         pTab = 0;
3530         goto error_out;
3531       }
3532     }
3533   }
3534 
3535   /* The following block stores the meta information that will be returned
3536   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3537   ** and autoinc. At this point there are two possibilities:
3538   **
3539   **     1. The specified column name was rowid", "oid" or "_rowid_"
3540   **        and there is no explicitly declared IPK column.
3541   **
3542   **     2. The table is not a view and the column name identified an
3543   **        explicitly declared column. Copy meta information from *pCol.
3544   */
3545   if( pCol ){
3546     zDataType = sqlite3ColumnType(pCol,0);
3547     zCollSeq = pCol->zColl;
3548     notnull = pCol->notNull!=0;
3549     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3550     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3551   }else{
3552     zDataType = "INTEGER";
3553     primarykey = 1;
3554   }
3555   if( !zCollSeq ){
3556     zCollSeq = sqlite3StrBINARY;
3557   }
3558 
3559 error_out:
3560   sqlite3BtreeLeaveAll(db);
3561 
3562   /* Whether the function call succeeded or failed, set the output parameters
3563   ** to whatever their local counterparts contain. If an error did occur,
3564   ** this has the effect of zeroing all output parameters.
3565   */
3566   if( pzDataType ) *pzDataType = zDataType;
3567   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3568   if( pNotNull ) *pNotNull = notnull;
3569   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3570   if( pAutoinc ) *pAutoinc = autoinc;
3571 
3572   if( SQLITE_OK==rc && !pTab ){
3573     sqlite3DbFree(db, zErrMsg);
3574     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3575         zColumnName);
3576     rc = SQLITE_ERROR;
3577   }
3578   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3579   sqlite3DbFree(db, zErrMsg);
3580   rc = sqlite3ApiExit(db, rc);
3581   sqlite3_mutex_leave(db->mutex);
3582   return rc;
3583 }
3584 
3585 /*
3586 ** Sleep for a little while.  Return the amount of time slept.
3587 */
3588 int sqlite3_sleep(int ms){
3589   sqlite3_vfs *pVfs;
3590   int rc;
3591   pVfs = sqlite3_vfs_find(0);
3592   if( pVfs==0 ) return 0;
3593 
3594   /* This function works in milliseconds, but the underlying OsSleep()
3595   ** API uses microseconds. Hence the 1000's.
3596   */
3597   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3598   return rc;
3599 }
3600 
3601 /*
3602 ** Enable or disable the extended result codes.
3603 */
3604 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3605 #ifdef SQLITE_ENABLE_API_ARMOR
3606   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3607 #endif
3608   sqlite3_mutex_enter(db->mutex);
3609   db->errMask = onoff ? 0xffffffff : 0xff;
3610   sqlite3_mutex_leave(db->mutex);
3611   return SQLITE_OK;
3612 }
3613 
3614 /*
3615 ** Invoke the xFileControl method on a particular database.
3616 */
3617 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3618   int rc = SQLITE_ERROR;
3619   Btree *pBtree;
3620 
3621 #ifdef SQLITE_ENABLE_API_ARMOR
3622   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3623 #endif
3624   sqlite3_mutex_enter(db->mutex);
3625   pBtree = sqlite3DbNameToBtree(db, zDbName);
3626   if( pBtree ){
3627     Pager *pPager;
3628     sqlite3_file *fd;
3629     sqlite3BtreeEnter(pBtree);
3630     pPager = sqlite3BtreePager(pBtree);
3631     assert( pPager!=0 );
3632     fd = sqlite3PagerFile(pPager);
3633     assert( fd!=0 );
3634     if( op==SQLITE_FCNTL_FILE_POINTER ){
3635       *(sqlite3_file**)pArg = fd;
3636       rc = SQLITE_OK;
3637     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3638       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3639       rc = SQLITE_OK;
3640     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3641       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3642       rc = SQLITE_OK;
3643     }else{
3644       rc = sqlite3OsFileControl(fd, op, pArg);
3645     }
3646     sqlite3BtreeLeave(pBtree);
3647   }
3648   sqlite3_mutex_leave(db->mutex);
3649   return rc;
3650 }
3651 
3652 /*
3653 ** Interface to the testing logic.
3654 */
3655 int sqlite3_test_control(int op, ...){
3656   int rc = 0;
3657 #ifdef SQLITE_UNTESTABLE
3658   UNUSED_PARAMETER(op);
3659 #else
3660   va_list ap;
3661   va_start(ap, op);
3662   switch( op ){
3663 
3664     /*
3665     ** Save the current state of the PRNG.
3666     */
3667     case SQLITE_TESTCTRL_PRNG_SAVE: {
3668       sqlite3PrngSaveState();
3669       break;
3670     }
3671 
3672     /*
3673     ** Restore the state of the PRNG to the last state saved using
3674     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3675     ** this verb acts like PRNG_RESET.
3676     */
3677     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3678       sqlite3PrngRestoreState();
3679       break;
3680     }
3681 
3682     /*
3683     ** Reset the PRNG back to its uninitialized state.  The next call
3684     ** to sqlite3_randomness() will reseed the PRNG using a single call
3685     ** to the xRandomness method of the default VFS.
3686     */
3687     case SQLITE_TESTCTRL_PRNG_RESET: {
3688       sqlite3_randomness(0,0);
3689       break;
3690     }
3691 
3692     /*
3693     **  sqlite3_test_control(BITVEC_TEST, size, program)
3694     **
3695     ** Run a test against a Bitvec object of size.  The program argument
3696     ** is an array of integers that defines the test.  Return -1 on a
3697     ** memory allocation error, 0 on success, or non-zero for an error.
3698     ** See the sqlite3BitvecBuiltinTest() for additional information.
3699     */
3700     case SQLITE_TESTCTRL_BITVEC_TEST: {
3701       int sz = va_arg(ap, int);
3702       int *aProg = va_arg(ap, int*);
3703       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3704       break;
3705     }
3706 
3707     /*
3708     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3709     **
3710     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3711     ** if xCallback is not NULL.
3712     **
3713     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3714     ** is called immediately after installing the new callback and the return
3715     ** value from sqlite3FaultSim(0) becomes the return from
3716     ** sqlite3_test_control().
3717     */
3718     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3719       /* MSVC is picky about pulling func ptrs from va lists.
3720       ** http://support.microsoft.com/kb/47961
3721       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3722       */
3723       typedef int(*TESTCALLBACKFUNC_t)(int);
3724       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3725       rc = sqlite3FaultSim(0);
3726       break;
3727     }
3728 
3729     /*
3730     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3731     **
3732     ** Register hooks to call to indicate which malloc() failures
3733     ** are benign.
3734     */
3735     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3736       typedef void (*void_function)(void);
3737       void_function xBenignBegin;
3738       void_function xBenignEnd;
3739       xBenignBegin = va_arg(ap, void_function);
3740       xBenignEnd = va_arg(ap, void_function);
3741       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3742       break;
3743     }
3744 
3745     /*
3746     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3747     **
3748     ** Set the PENDING byte to the value in the argument, if X>0.
3749     ** Make no changes if X==0.  Return the value of the pending byte
3750     ** as it existing before this routine was called.
3751     **
3752     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3753     ** an incompatible database file format.  Changing the PENDING byte
3754     ** while any database connection is open results in undefined and
3755     ** deleterious behavior.
3756     */
3757     case SQLITE_TESTCTRL_PENDING_BYTE: {
3758       rc = PENDING_BYTE;
3759 #ifndef SQLITE_OMIT_WSD
3760       {
3761         unsigned int newVal = va_arg(ap, unsigned int);
3762         if( newVal ) sqlite3PendingByte = newVal;
3763       }
3764 #endif
3765       break;
3766     }
3767 
3768     /*
3769     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3770     **
3771     ** This action provides a run-time test to see whether or not
3772     ** assert() was enabled at compile-time.  If X is true and assert()
3773     ** is enabled, then the return value is true.  If X is true and
3774     ** assert() is disabled, then the return value is zero.  If X is
3775     ** false and assert() is enabled, then the assertion fires and the
3776     ** process aborts.  If X is false and assert() is disabled, then the
3777     ** return value is zero.
3778     */
3779     case SQLITE_TESTCTRL_ASSERT: {
3780       volatile int x = 0;
3781       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3782       rc = x;
3783       break;
3784     }
3785 
3786 
3787     /*
3788     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3789     **
3790     ** This action provides a run-time test to see how the ALWAYS and
3791     ** NEVER macros were defined at compile-time.
3792     **
3793     ** The return value is ALWAYS(X) if X is true, or 0 if X is false.
3794     **
3795     ** The recommended test is X==2.  If the return value is 2, that means
3796     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3797     ** default setting.  If the return value is 1, then ALWAYS() is either
3798     ** hard-coded to true or else it asserts if its argument is false.
3799     ** The first behavior (hard-coded to true) is the case if
3800     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3801     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3802     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3803     **
3804     ** The run-time test procedure might look something like this:
3805     **
3806     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3807     **      // ALWAYS() and NEVER() are no-op pass-through macros
3808     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3809     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3810     **    }else{
3811     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3812     **    }
3813     */
3814     case SQLITE_TESTCTRL_ALWAYS: {
3815       int x = va_arg(ap,int);
3816       rc = x ? ALWAYS(x) : 0;
3817       break;
3818     }
3819 
3820     /*
3821     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3822     **
3823     ** The integer returned reveals the byte-order of the computer on which
3824     ** SQLite is running:
3825     **
3826     **       1     big-endian,    determined at run-time
3827     **      10     little-endian, determined at run-time
3828     **  432101     big-endian,    determined at compile-time
3829     **  123410     little-endian, determined at compile-time
3830     */
3831     case SQLITE_TESTCTRL_BYTEORDER: {
3832       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3833       break;
3834     }
3835 
3836     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3837     **
3838     ** Set the nReserve size to N for the main database on the database
3839     ** connection db.
3840     */
3841     case SQLITE_TESTCTRL_RESERVE: {
3842       sqlite3 *db = va_arg(ap, sqlite3*);
3843       int x = va_arg(ap,int);
3844       sqlite3_mutex_enter(db->mutex);
3845       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3846       sqlite3_mutex_leave(db->mutex);
3847       break;
3848     }
3849 
3850     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3851     **
3852     ** Enable or disable various optimizations for testing purposes.  The
3853     ** argument N is a bitmask of optimizations to be disabled.  For normal
3854     ** operation N should be 0.  The idea is that a test program (like the
3855     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3856     ** with various optimizations disabled to verify that the same answer
3857     ** is obtained in every case.
3858     */
3859     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3860       sqlite3 *db = va_arg(ap, sqlite3*);
3861       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3862       break;
3863     }
3864 
3865     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3866     **
3867     ** If parameter onoff is non-zero, configure the wrappers so that all
3868     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3869     ** undo this setting.
3870     */
3871     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3872       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3873       break;
3874     }
3875 
3876     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3877     **
3878     ** Set or clear a flag that indicates that the database file is always well-
3879     ** formed and never corrupt.  This flag is clear by default, indicating that
3880     ** database files might have arbitrary corruption.  Setting the flag during
3881     ** testing causes certain assert() statements in the code to be activated
3882     ** that demonstrat invariants on well-formed database files.
3883     */
3884     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3885       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3886       break;
3887     }
3888 
3889     /* Set the threshold at which OP_Once counters reset back to zero.
3890     ** By default this is 0x7ffffffe (over 2 billion), but that value is
3891     ** too big to test in a reasonable amount of time, so this control is
3892     ** provided to set a small and easily reachable reset value.
3893     */
3894     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
3895       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
3896       break;
3897     }
3898 
3899     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3900     **
3901     ** Set the VDBE coverage callback function to xCallback with context
3902     ** pointer ptr.
3903     */
3904     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3905 #ifdef SQLITE_VDBE_COVERAGE
3906       typedef void (*branch_callback)(void*,int,u8,u8);
3907       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3908       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3909 #endif
3910       break;
3911     }
3912 
3913     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3914     case SQLITE_TESTCTRL_SORTER_MMAP: {
3915       sqlite3 *db = va_arg(ap, sqlite3*);
3916       db->nMaxSorterMmap = va_arg(ap, int);
3917       break;
3918     }
3919 
3920     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3921     **
3922     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3923     ** not.
3924     */
3925     case SQLITE_TESTCTRL_ISINIT: {
3926       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3927       break;
3928     }
3929 
3930     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3931     **
3932     ** This test control is used to create imposter tables.  "db" is a pointer
3933     ** to the database connection.  dbName is the database name (ex: "main" or
3934     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3935     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3936     ** table should connect.
3937     **
3938     ** Enable imposter mode only when the schema has already been parsed.  Then
3939     ** run a single CREATE TABLE statement to construct the imposter table in
3940     ** the parsed schema.  Then turn imposter mode back off again.
3941     **
3942     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3943     ** the schema to be reparsed the next time it is needed.  This has the
3944     ** effect of erasing all imposter tables.
3945     */
3946     case SQLITE_TESTCTRL_IMPOSTER: {
3947       sqlite3 *db = va_arg(ap, sqlite3*);
3948       sqlite3_mutex_enter(db->mutex);
3949       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3950       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3951       db->init.newTnum = va_arg(ap,int);
3952       if( db->init.busy==0 && db->init.newTnum>0 ){
3953         sqlite3ResetAllSchemasOfConnection(db);
3954       }
3955       sqlite3_mutex_leave(db->mutex);
3956       break;
3957     }
3958 
3959 #if defined(YYCOVERAGE)
3960     /*  sqlite3_test_control(SQLITE_TESTCTRL_PARSER_COVERAGE, FILE *out)
3961     **
3962     ** This test control (only available when SQLite is compiled with
3963     ** -DYYCOVERAGE) writes a report onto "out" that shows all
3964     ** state/lookahead combinations in the parser state machine
3965     ** which are never exercised.  If any state is missed, make the
3966     ** return code SQLITE_ERROR.
3967     */
3968     case SQLITE_TESTCTRL_PARSER_COVERAGE: {
3969       FILE *out = va_arg(ap, FILE*);
3970       if( sqlite3ParserCoverage(out) ) rc = SQLITE_ERROR;
3971       break;
3972     }
3973 #endif /* defined(YYCOVERAGE) */
3974   }
3975   va_end(ap);
3976 #endif /* SQLITE_UNTESTABLE */
3977   return rc;
3978 }
3979 
3980 /*
3981 ** This is a utility routine, useful to VFS implementations, that checks
3982 ** to see if a database file was a URI that contained a specific query
3983 ** parameter, and if so obtains the value of the query parameter.
3984 **
3985 ** The zFilename argument is the filename pointer passed into the xOpen()
3986 ** method of a VFS implementation.  The zParam argument is the name of the
3987 ** query parameter we seek.  This routine returns the value of the zParam
3988 ** parameter if it exists.  If the parameter does not exist, this routine
3989 ** returns a NULL pointer.
3990 */
3991 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3992   if( zFilename==0 || zParam==0 ) return 0;
3993   zFilename += sqlite3Strlen30(zFilename) + 1;
3994   while( zFilename[0] ){
3995     int x = strcmp(zFilename, zParam);
3996     zFilename += sqlite3Strlen30(zFilename) + 1;
3997     if( x==0 ) return zFilename;
3998     zFilename += sqlite3Strlen30(zFilename) + 1;
3999   }
4000   return 0;
4001 }
4002 
4003 /*
4004 ** Return a boolean value for a query parameter.
4005 */
4006 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
4007   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4008   bDflt = bDflt!=0;
4009   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
4010 }
4011 
4012 /*
4013 ** Return a 64-bit integer value for a query parameter.
4014 */
4015 sqlite3_int64 sqlite3_uri_int64(
4016   const char *zFilename,    /* Filename as passed to xOpen */
4017   const char *zParam,       /* URI parameter sought */
4018   sqlite3_int64 bDflt       /* return if parameter is missing */
4019 ){
4020   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4021   sqlite3_int64 v;
4022   if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
4023     bDflt = v;
4024   }
4025   return bDflt;
4026 }
4027 
4028 /*
4029 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
4030 */
4031 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
4032   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
4033   return iDb<0 ? 0 : db->aDb[iDb].pBt;
4034 }
4035 
4036 /*
4037 ** Return the filename of the database associated with a database
4038 ** connection.
4039 */
4040 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
4041   Btree *pBt;
4042 #ifdef SQLITE_ENABLE_API_ARMOR
4043   if( !sqlite3SafetyCheckOk(db) ){
4044     (void)SQLITE_MISUSE_BKPT;
4045     return 0;
4046   }
4047 #endif
4048   pBt = sqlite3DbNameToBtree(db, zDbName);
4049   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
4050 }
4051 
4052 /*
4053 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
4054 ** no such database exists.
4055 */
4056 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
4057   Btree *pBt;
4058 #ifdef SQLITE_ENABLE_API_ARMOR
4059   if( !sqlite3SafetyCheckOk(db) ){
4060     (void)SQLITE_MISUSE_BKPT;
4061     return -1;
4062   }
4063 #endif
4064   pBt = sqlite3DbNameToBtree(db, zDbName);
4065   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
4066 }
4067 
4068 #ifdef SQLITE_ENABLE_SNAPSHOT
4069 /*
4070 ** Obtain a snapshot handle for the snapshot of database zDb currently
4071 ** being read by handle db.
4072 */
4073 int sqlite3_snapshot_get(
4074   sqlite3 *db,
4075   const char *zDb,
4076   sqlite3_snapshot **ppSnapshot
4077 ){
4078   int rc = SQLITE_ERROR;
4079 #ifndef SQLITE_OMIT_WAL
4080 
4081 #ifdef SQLITE_ENABLE_API_ARMOR
4082   if( !sqlite3SafetyCheckOk(db) ){
4083     return SQLITE_MISUSE_BKPT;
4084   }
4085 #endif
4086   sqlite3_mutex_enter(db->mutex);
4087 
4088   if( db->autoCommit==0 ){
4089     int iDb = sqlite3FindDbName(db, zDb);
4090     if( iDb==0 || iDb>1 ){
4091       Btree *pBt = db->aDb[iDb].pBt;
4092       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4093         rc = sqlite3BtreeBeginTrans(pBt, 0);
4094         if( rc==SQLITE_OK ){
4095           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4096         }
4097       }
4098     }
4099   }
4100 
4101   sqlite3_mutex_leave(db->mutex);
4102 #endif   /* SQLITE_OMIT_WAL */
4103   return rc;
4104 }
4105 
4106 /*
4107 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4108 */
4109 int sqlite3_snapshot_open(
4110   sqlite3 *db,
4111   const char *zDb,
4112   sqlite3_snapshot *pSnapshot
4113 ){
4114   int rc = SQLITE_ERROR;
4115 #ifndef SQLITE_OMIT_WAL
4116 
4117 #ifdef SQLITE_ENABLE_API_ARMOR
4118   if( !sqlite3SafetyCheckOk(db) ){
4119     return SQLITE_MISUSE_BKPT;
4120   }
4121 #endif
4122   sqlite3_mutex_enter(db->mutex);
4123   if( db->autoCommit==0 ){
4124     int iDb;
4125     iDb = sqlite3FindDbName(db, zDb);
4126     if( iDb==0 || iDb>1 ){
4127       Btree *pBt = db->aDb[iDb].pBt;
4128       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4129         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
4130         if( rc==SQLITE_OK ){
4131           rc = sqlite3BtreeBeginTrans(pBt, 0);
4132           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
4133         }
4134       }
4135     }
4136   }
4137 
4138   sqlite3_mutex_leave(db->mutex);
4139 #endif   /* SQLITE_OMIT_WAL */
4140   return rc;
4141 }
4142 
4143 /*
4144 ** Recover as many snapshots as possible from the wal file associated with
4145 ** schema zDb of database db.
4146 */
4147 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4148   int rc = SQLITE_ERROR;
4149   int iDb;
4150 #ifndef SQLITE_OMIT_WAL
4151 
4152 #ifdef SQLITE_ENABLE_API_ARMOR
4153   if( !sqlite3SafetyCheckOk(db) ){
4154     return SQLITE_MISUSE_BKPT;
4155   }
4156 #endif
4157 
4158   sqlite3_mutex_enter(db->mutex);
4159   iDb = sqlite3FindDbName(db, zDb);
4160   if( iDb==0 || iDb>1 ){
4161     Btree *pBt = db->aDb[iDb].pBt;
4162     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4163       rc = sqlite3BtreeBeginTrans(pBt, 0);
4164       if( rc==SQLITE_OK ){
4165         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4166         sqlite3BtreeCommit(pBt);
4167       }
4168     }
4169   }
4170   sqlite3_mutex_leave(db->mutex);
4171 #endif   /* SQLITE_OMIT_WAL */
4172   return rc;
4173 }
4174 
4175 /*
4176 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4177 */
4178 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4179   sqlite3_free(pSnapshot);
4180 }
4181 #endif /* SQLITE_ENABLE_SNAPSHOT */
4182 
4183 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4184 /*
4185 ** Given the name of a compile-time option, return true if that option
4186 ** was used and false if not.
4187 **
4188 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4189 ** is not required for a match.
4190 */
4191 int sqlite3_compileoption_used(const char *zOptName){
4192   int i, n;
4193   int nOpt;
4194   const char **azCompileOpt;
4195 
4196 #if SQLITE_ENABLE_API_ARMOR
4197   if( zOptName==0 ){
4198     (void)SQLITE_MISUSE_BKPT;
4199     return 0;
4200   }
4201 #endif
4202 
4203   azCompileOpt = sqlite3CompileOptions(&nOpt);
4204 
4205   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4206   n = sqlite3Strlen30(zOptName);
4207 
4208   /* Since nOpt is normally in single digits, a linear search is
4209   ** adequate. No need for a binary search. */
4210   for(i=0; i<nOpt; i++){
4211     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4212      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4213     ){
4214       return 1;
4215     }
4216   }
4217   return 0;
4218 }
4219 
4220 /*
4221 ** Return the N-th compile-time option string.  If N is out of range,
4222 ** return a NULL pointer.
4223 */
4224 const char *sqlite3_compileoption_get(int N){
4225   int nOpt;
4226   const char **azCompileOpt;
4227   azCompileOpt = sqlite3CompileOptions(&nOpt);
4228   if( N>=0 && N<nOpt ){
4229     return azCompileOpt[N];
4230   }
4231   return 0;
4232 }
4233 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4234