xref: /sqlite-3.40.0/src/main.c (revision 8c53b4e7)
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         { SQLITE_DBCONFIG_DEFENSIVE,             SQLITE_Defensive      },
839       };
840       unsigned int i;
841       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
842       for(i=0; i<ArraySize(aFlagOp); i++){
843         if( aFlagOp[i].op==op ){
844           int onoff = va_arg(ap, int);
845           int *pRes = va_arg(ap, int*);
846           u32 oldFlags = db->flags;
847           if( onoff>0 ){
848             db->flags |= aFlagOp[i].mask;
849           }else if( onoff==0 ){
850             db->flags &= ~aFlagOp[i].mask;
851           }
852           if( oldFlags!=db->flags ){
853             sqlite3ExpirePreparedStatements(db, 0);
854           }
855           if( pRes ){
856             *pRes = (db->flags & aFlagOp[i].mask)!=0;
857           }
858           rc = SQLITE_OK;
859           break;
860         }
861       }
862       break;
863     }
864   }
865   va_end(ap);
866   return rc;
867 }
868 
869 
870 /*
871 ** Return true if the buffer z[0..n-1] contains all spaces.
872 */
873 static int allSpaces(const char *z, int n){
874   while( n>0 && z[n-1]==' ' ){ n--; }
875   return n==0;
876 }
877 
878 /*
879 ** This is the default collating function named "BINARY" which is always
880 ** available.
881 **
882 ** If the padFlag argument is not NULL then space padding at the end
883 ** of strings is ignored.  This implements the RTRIM collation.
884 */
885 static int binCollFunc(
886   void *padFlag,
887   int nKey1, const void *pKey1,
888   int nKey2, const void *pKey2
889 ){
890   int rc, n;
891   n = nKey1<nKey2 ? nKey1 : nKey2;
892   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
893   ** strings byte by byte using the memcmp() function from the standard C
894   ** library. */
895   assert( pKey1 && pKey2 );
896   rc = memcmp(pKey1, pKey2, n);
897   if( rc==0 ){
898     if( padFlag
899      && allSpaces(((char*)pKey1)+n, nKey1-n)
900      && allSpaces(((char*)pKey2)+n, nKey2-n)
901     ){
902       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
903       ** spaces at the end of either string do not change the result. In other
904       ** words, strings will compare equal to one another as long as they
905       ** differ only in the number of spaces at the end.
906       */
907     }else{
908       rc = nKey1 - nKey2;
909     }
910   }
911   return rc;
912 }
913 
914 /*
915 ** Return true if CollSeq is the default built-in BINARY.
916 */
917 int sqlite3IsBinary(const CollSeq *p){
918   assert( p==0 || p->xCmp!=binCollFunc || p->pUser!=0
919             || strcmp(p->zName,"BINARY")==0 );
920   return p==0 || (p->xCmp==binCollFunc && p->pUser==0);
921 }
922 
923 /*
924 ** Another built-in collating sequence: NOCASE.
925 **
926 ** This collating sequence is intended to be used for "case independent
927 ** comparison". SQLite's knowledge of upper and lower case equivalents
928 ** extends only to the 26 characters used in the English language.
929 **
930 ** At the moment there is only a UTF-8 implementation.
931 */
932 static int nocaseCollatingFunc(
933   void *NotUsed,
934   int nKey1, const void *pKey1,
935   int nKey2, const void *pKey2
936 ){
937   int r = sqlite3StrNICmp(
938       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
939   UNUSED_PARAMETER(NotUsed);
940   if( 0==r ){
941     r = nKey1-nKey2;
942   }
943   return r;
944 }
945 
946 /*
947 ** Return the ROWID of the most recent insert
948 */
949 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
950 #ifdef SQLITE_ENABLE_API_ARMOR
951   if( !sqlite3SafetyCheckOk(db) ){
952     (void)SQLITE_MISUSE_BKPT;
953     return 0;
954   }
955 #endif
956   return db->lastRowid;
957 }
958 
959 /*
960 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
961 */
962 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
963 #ifdef SQLITE_ENABLE_API_ARMOR
964   if( !sqlite3SafetyCheckOk(db) ){
965     (void)SQLITE_MISUSE_BKPT;
966     return;
967   }
968 #endif
969   sqlite3_mutex_enter(db->mutex);
970   db->lastRowid = iRowid;
971   sqlite3_mutex_leave(db->mutex);
972 }
973 
974 /*
975 ** Return the number of changes in the most recent call to sqlite3_exec().
976 */
977 int sqlite3_changes(sqlite3 *db){
978 #ifdef SQLITE_ENABLE_API_ARMOR
979   if( !sqlite3SafetyCheckOk(db) ){
980     (void)SQLITE_MISUSE_BKPT;
981     return 0;
982   }
983 #endif
984   return db->nChange;
985 }
986 
987 /*
988 ** Return the number of changes since the database handle was opened.
989 */
990 int sqlite3_total_changes(sqlite3 *db){
991 #ifdef SQLITE_ENABLE_API_ARMOR
992   if( !sqlite3SafetyCheckOk(db) ){
993     (void)SQLITE_MISUSE_BKPT;
994     return 0;
995   }
996 #endif
997   return db->nTotalChange;
998 }
999 
1000 /*
1001 ** Close all open savepoints. This function only manipulates fields of the
1002 ** database handle object, it does not close any savepoints that may be open
1003 ** at the b-tree/pager level.
1004 */
1005 void sqlite3CloseSavepoints(sqlite3 *db){
1006   while( db->pSavepoint ){
1007     Savepoint *pTmp = db->pSavepoint;
1008     db->pSavepoint = pTmp->pNext;
1009     sqlite3DbFree(db, pTmp);
1010   }
1011   db->nSavepoint = 0;
1012   db->nStatement = 0;
1013   db->isTransactionSavepoint = 0;
1014 }
1015 
1016 /*
1017 ** Invoke the destructor function associated with FuncDef p, if any. Except,
1018 ** if this is not the last copy of the function, do not invoke it. Multiple
1019 ** copies of a single function are created when create_function() is called
1020 ** with SQLITE_ANY as the encoding.
1021 */
1022 static void functionDestroy(sqlite3 *db, FuncDef *p){
1023   FuncDestructor *pDestructor = p->u.pDestructor;
1024   if( pDestructor ){
1025     pDestructor->nRef--;
1026     if( pDestructor->nRef==0 ){
1027       pDestructor->xDestroy(pDestructor->pUserData);
1028       sqlite3DbFree(db, pDestructor);
1029     }
1030   }
1031 }
1032 
1033 /*
1034 ** Disconnect all sqlite3_vtab objects that belong to database connection
1035 ** db. This is called when db is being closed.
1036 */
1037 static void disconnectAllVtab(sqlite3 *db){
1038 #ifndef SQLITE_OMIT_VIRTUALTABLE
1039   int i;
1040   HashElem *p;
1041   sqlite3BtreeEnterAll(db);
1042   for(i=0; i<db->nDb; i++){
1043     Schema *pSchema = db->aDb[i].pSchema;
1044     if( pSchema ){
1045       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1046         Table *pTab = (Table *)sqliteHashData(p);
1047         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1048       }
1049     }
1050   }
1051   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1052     Module *pMod = (Module *)sqliteHashData(p);
1053     if( pMod->pEpoTab ){
1054       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1055     }
1056   }
1057   sqlite3VtabUnlockList(db);
1058   sqlite3BtreeLeaveAll(db);
1059 #else
1060   UNUSED_PARAMETER(db);
1061 #endif
1062 }
1063 
1064 /*
1065 ** Return TRUE if database connection db has unfinalized prepared
1066 ** statements or unfinished sqlite3_backup objects.
1067 */
1068 static int connectionIsBusy(sqlite3 *db){
1069   int j;
1070   assert( sqlite3_mutex_held(db->mutex) );
1071   if( db->pVdbe ) return 1;
1072   for(j=0; j<db->nDb; j++){
1073     Btree *pBt = db->aDb[j].pBt;
1074     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1075   }
1076   return 0;
1077 }
1078 
1079 /*
1080 ** Close an existing SQLite database
1081 */
1082 static int sqlite3Close(sqlite3 *db, int forceZombie){
1083   if( !db ){
1084     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1085     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1086     return SQLITE_OK;
1087   }
1088   if( !sqlite3SafetyCheckSickOrOk(db) ){
1089     return SQLITE_MISUSE_BKPT;
1090   }
1091   sqlite3_mutex_enter(db->mutex);
1092   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1093     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1094   }
1095 
1096   /* Force xDisconnect calls on all virtual tables */
1097   disconnectAllVtab(db);
1098 
1099   /* If a transaction is open, the disconnectAllVtab() call above
1100   ** will not have called the xDisconnect() method on any virtual
1101   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1102   ** call will do so. We need to do this before the check for active
1103   ** SQL statements below, as the v-table implementation may be storing
1104   ** some prepared statements internally.
1105   */
1106   sqlite3VtabRollback(db);
1107 
1108   /* Legacy behavior (sqlite3_close() behavior) is to return
1109   ** SQLITE_BUSY if the connection can not be closed immediately.
1110   */
1111   if( !forceZombie && connectionIsBusy(db) ){
1112     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1113        "statements or unfinished backups");
1114     sqlite3_mutex_leave(db->mutex);
1115     return SQLITE_BUSY;
1116   }
1117 
1118 #ifdef SQLITE_ENABLE_SQLLOG
1119   if( sqlite3GlobalConfig.xSqllog ){
1120     /* Closing the handle. Fourth parameter is passed the value 2. */
1121     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1122   }
1123 #endif
1124 
1125   /* Convert the connection into a zombie and then close it.
1126   */
1127   db->magic = SQLITE_MAGIC_ZOMBIE;
1128   sqlite3LeaveMutexAndCloseZombie(db);
1129   return SQLITE_OK;
1130 }
1131 
1132 /*
1133 ** Two variations on the public interface for closing a database
1134 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1135 ** leaves the connection option if there are unfinalized prepared
1136 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1137 ** version forces the connection to become a zombie if there are
1138 ** unclosed resources, and arranges for deallocation when the last
1139 ** prepare statement or sqlite3_backup closes.
1140 */
1141 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1142 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1143 
1144 
1145 /*
1146 ** Close the mutex on database connection db.
1147 **
1148 ** Furthermore, if database connection db is a zombie (meaning that there
1149 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1150 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1151 ** finished, then free all resources.
1152 */
1153 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1154   HashElem *i;                    /* Hash table iterator */
1155   int j;
1156 
1157   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1158   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1159   ** then just leave the mutex and return.
1160   */
1161   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1162     sqlite3_mutex_leave(db->mutex);
1163     return;
1164   }
1165 
1166   /* If we reach this point, it means that the database connection has
1167   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1168   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1169   ** go ahead and free all resources.
1170   */
1171 
1172   /* If a transaction is open, roll it back. This also ensures that if
1173   ** any database schemas have been modified by an uncommitted transaction
1174   ** they are reset. And that the required b-tree mutex is held to make
1175   ** the pager rollback and schema reset an atomic operation. */
1176   sqlite3RollbackAll(db, SQLITE_OK);
1177 
1178   /* Free any outstanding Savepoint structures. */
1179   sqlite3CloseSavepoints(db);
1180 
1181   /* Close all database connections */
1182   for(j=0; j<db->nDb; j++){
1183     struct Db *pDb = &db->aDb[j];
1184     if( pDb->pBt ){
1185       sqlite3BtreeClose(pDb->pBt);
1186       pDb->pBt = 0;
1187       if( j!=1 ){
1188         pDb->pSchema = 0;
1189       }
1190     }
1191   }
1192   /* Clear the TEMP schema separately and last */
1193   if( db->aDb[1].pSchema ){
1194     sqlite3SchemaClear(db->aDb[1].pSchema);
1195   }
1196   sqlite3VtabUnlockList(db);
1197 
1198   /* Free up the array of auxiliary databases */
1199   sqlite3CollapseDatabaseArray(db);
1200   assert( db->nDb<=2 );
1201   assert( db->aDb==db->aDbStatic );
1202 
1203   /* Tell the code in notify.c that the connection no longer holds any
1204   ** locks and does not require any further unlock-notify callbacks.
1205   */
1206   sqlite3ConnectionClosed(db);
1207 
1208   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1209     FuncDef *pNext, *p;
1210     p = sqliteHashData(i);
1211     do{
1212       functionDestroy(db, p);
1213       pNext = p->pNext;
1214       sqlite3DbFree(db, p);
1215       p = pNext;
1216     }while( p );
1217   }
1218   sqlite3HashClear(&db->aFunc);
1219   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1220     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1221     /* Invoke any destructors registered for collation sequence user data. */
1222     for(j=0; j<3; j++){
1223       if( pColl[j].xDel ){
1224         pColl[j].xDel(pColl[j].pUser);
1225       }
1226     }
1227     sqlite3DbFree(db, pColl);
1228   }
1229   sqlite3HashClear(&db->aCollSeq);
1230 #ifndef SQLITE_OMIT_VIRTUALTABLE
1231   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1232     Module *pMod = (Module *)sqliteHashData(i);
1233     if( pMod->xDestroy ){
1234       pMod->xDestroy(pMod->pAux);
1235     }
1236     sqlite3VtabEponymousTableClear(db, pMod);
1237     sqlite3DbFree(db, pMod);
1238   }
1239   sqlite3HashClear(&db->aModule);
1240 #endif
1241 
1242   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1243   sqlite3ValueFree(db->pErr);
1244   sqlite3CloseExtensions(db);
1245 #if SQLITE_USER_AUTHENTICATION
1246   sqlite3_free(db->auth.zAuthUser);
1247   sqlite3_free(db->auth.zAuthPW);
1248 #endif
1249 
1250   db->magic = SQLITE_MAGIC_ERROR;
1251 
1252   /* The temp-database schema is allocated differently from the other schema
1253   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1254   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1255   ** the same sqliteMalloc() as the one that allocates the database
1256   ** structure?
1257   */
1258   sqlite3DbFree(db, db->aDb[1].pSchema);
1259   sqlite3_mutex_leave(db->mutex);
1260   db->magic = SQLITE_MAGIC_CLOSED;
1261   sqlite3_mutex_free(db->mutex);
1262   assert( sqlite3LookasideUsed(db,0)==0 );
1263   if( db->lookaside.bMalloced ){
1264     sqlite3_free(db->lookaside.pStart);
1265   }
1266   sqlite3_free(db);
1267 }
1268 
1269 /*
1270 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1271 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1272 ** breaker") and made to return tripCode if there are any further
1273 ** attempts to use that cursor.  Read cursors remain open and valid
1274 ** but are "saved" in case the table pages are moved around.
1275 */
1276 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1277   int i;
1278   int inTrans = 0;
1279   int schemaChange;
1280   assert( sqlite3_mutex_held(db->mutex) );
1281   sqlite3BeginBenignMalloc();
1282 
1283   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1284   ** This is important in case the transaction being rolled back has
1285   ** modified the database schema. If the b-tree mutexes are not taken
1286   ** here, then another shared-cache connection might sneak in between
1287   ** the database rollback and schema reset, which can cause false
1288   ** corruption reports in some cases.  */
1289   sqlite3BtreeEnterAll(db);
1290   schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
1291 
1292   for(i=0; i<db->nDb; i++){
1293     Btree *p = db->aDb[i].pBt;
1294     if( p ){
1295       if( sqlite3BtreeIsInTrans(p) ){
1296         inTrans = 1;
1297       }
1298       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1299     }
1300   }
1301   sqlite3VtabRollback(db);
1302   sqlite3EndBenignMalloc();
1303 
1304   if( schemaChange ){
1305     sqlite3ExpirePreparedStatements(db, 0);
1306     sqlite3ResetAllSchemasOfConnection(db);
1307   }
1308   sqlite3BtreeLeaveAll(db);
1309 
1310   /* Any deferred constraint violations have now been resolved. */
1311   db->nDeferredCons = 0;
1312   db->nDeferredImmCons = 0;
1313   db->flags &= ~SQLITE_DeferFKs;
1314 
1315   /* If one has been configured, invoke the rollback-hook callback */
1316   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1317     db->xRollbackCallback(db->pRollbackArg);
1318   }
1319 }
1320 
1321 /*
1322 ** Return a static string containing the name corresponding to the error code
1323 ** specified in the argument.
1324 */
1325 #if defined(SQLITE_NEED_ERR_NAME)
1326 const char *sqlite3ErrName(int rc){
1327   const char *zName = 0;
1328   int i, origRc = rc;
1329   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1330     switch( rc ){
1331       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1332       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1333       case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;
1334       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1335       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1336       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1337       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1338       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1339       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1340       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1341       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1342       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1343       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1344       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1345       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1346       case SQLITE_READONLY_CANTINIT:  zName = "SQLITE_READONLY_CANTINIT"; break;
1347       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1348       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1349       case SQLITE_READONLY_DIRECTORY: zName = "SQLITE_READONLY_DIRECTORY";break;
1350       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1351       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1352       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1353       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1354       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1355       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1356       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1357       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1358       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1359       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1360       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1361       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1362       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1363       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1364       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1365                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1366       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1367       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1368       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1369       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1370       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1371       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1372       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1373       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1374       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1375       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1376       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1377       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1378       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1379       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1380       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1381       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1382       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1383       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1384       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1385       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1386       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1387       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1388       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1389       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1390       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1391       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1392       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1393       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1394       case SQLITE_CONSTRAINT_FOREIGNKEY:
1395                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1396       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1397       case SQLITE_CONSTRAINT_PRIMARYKEY:
1398                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1399       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1400       case SQLITE_CONSTRAINT_COMMITHOOK:
1401                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1402       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1403       case SQLITE_CONSTRAINT_FUNCTION:
1404                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1405       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1406       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1407       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1408       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1409       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1410       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1411       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1412       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1413       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1414       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1415       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1416       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1417                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1418       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1419       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1420       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1421     }
1422   }
1423   if( zName==0 ){
1424     static char zBuf[50];
1425     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1426     zName = zBuf;
1427   }
1428   return zName;
1429 }
1430 #endif
1431 
1432 /*
1433 ** Return a static string that describes the kind of error specified in the
1434 ** argument.
1435 */
1436 const char *sqlite3ErrStr(int rc){
1437   static const char* const aMsg[] = {
1438     /* SQLITE_OK          */ "not an error",
1439     /* SQLITE_ERROR       */ "SQL logic error",
1440     /* SQLITE_INTERNAL    */ 0,
1441     /* SQLITE_PERM        */ "access permission denied",
1442     /* SQLITE_ABORT       */ "query aborted",
1443     /* SQLITE_BUSY        */ "database is locked",
1444     /* SQLITE_LOCKED      */ "database table is locked",
1445     /* SQLITE_NOMEM       */ "out of memory",
1446     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1447     /* SQLITE_INTERRUPT   */ "interrupted",
1448     /* SQLITE_IOERR       */ "disk I/O error",
1449     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1450     /* SQLITE_NOTFOUND    */ "unknown operation",
1451     /* SQLITE_FULL        */ "database or disk is full",
1452     /* SQLITE_CANTOPEN    */ "unable to open database file",
1453     /* SQLITE_PROTOCOL    */ "locking protocol",
1454     /* SQLITE_EMPTY       */ 0,
1455     /* SQLITE_SCHEMA      */ "database schema has changed",
1456     /* SQLITE_TOOBIG      */ "string or blob too big",
1457     /* SQLITE_CONSTRAINT  */ "constraint failed",
1458     /* SQLITE_MISMATCH    */ "datatype mismatch",
1459     /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
1460 #ifdef SQLITE_DISABLE_LFS
1461     /* SQLITE_NOLFS       */ "large file support is disabled",
1462 #else
1463     /* SQLITE_NOLFS       */ 0,
1464 #endif
1465     /* SQLITE_AUTH        */ "authorization denied",
1466     /* SQLITE_FORMAT      */ 0,
1467     /* SQLITE_RANGE       */ "column index out of range",
1468     /* SQLITE_NOTADB      */ "file is not a database",
1469     /* SQLITE_NOTICE      */ "notification message",
1470     /* SQLITE_WARNING     */ "warning message",
1471   };
1472   const char *zErr = "unknown error";
1473   switch( rc ){
1474     case SQLITE_ABORT_ROLLBACK: {
1475       zErr = "abort due to ROLLBACK";
1476       break;
1477     }
1478     case SQLITE_ROW: {
1479       zErr = "another row available";
1480       break;
1481     }
1482     case SQLITE_DONE: {
1483       zErr = "no more rows available";
1484       break;
1485     }
1486     default: {
1487       rc &= 0xff;
1488       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1489         zErr = aMsg[rc];
1490       }
1491       break;
1492     }
1493   }
1494   return zErr;
1495 }
1496 
1497 /*
1498 ** This routine implements a busy callback that sleeps and tries
1499 ** again until a timeout value is reached.  The timeout value is
1500 ** an integer number of milliseconds passed in as the first
1501 ** argument.
1502 **
1503 ** Return non-zero to retry the lock.  Return zero to stop trying
1504 ** and cause SQLite to return SQLITE_BUSY.
1505 */
1506 static int sqliteDefaultBusyCallback(
1507   void *ptr,               /* Database connection */
1508   int count,               /* Number of times table has been busy */
1509   sqlite3_file *pFile      /* The file on which the lock occurred */
1510 ){
1511 #if SQLITE_OS_WIN || HAVE_USLEEP
1512   /* This case is for systems that have support for sleeping for fractions of
1513   ** a second.  Examples:  All windows systems, unix systems with usleep() */
1514   static const u8 delays[] =
1515      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1516   static const u8 totals[] =
1517      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1518 # define NDELAY ArraySize(delays)
1519   sqlite3 *db = (sqlite3 *)ptr;
1520   int tmout = db->busyTimeout;
1521   int delay, prior;
1522 
1523 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
1524   if( sqlite3OsFileControl(pFile,SQLITE_FCNTL_LOCK_TIMEOUT,&tmout)==SQLITE_OK ){
1525     if( count ){
1526       tmout = 0;
1527       sqlite3OsFileControl(pFile, SQLITE_FCNTL_LOCK_TIMEOUT, &tmout);
1528       return 0;
1529     }else{
1530       return 1;
1531     }
1532   }
1533 #else
1534   UNUSED_PARAMETER(pFile);
1535 #endif
1536   assert( count>=0 );
1537   if( count < NDELAY ){
1538     delay = delays[count];
1539     prior = totals[count];
1540   }else{
1541     delay = delays[NDELAY-1];
1542     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1543   }
1544   if( prior + delay > tmout ){
1545     delay = tmout - prior;
1546     if( delay<=0 ) return 0;
1547   }
1548   sqlite3OsSleep(db->pVfs, delay*1000);
1549   return 1;
1550 #else
1551   /* This case for unix systems that lack usleep() support.  Sleeping
1552   ** must be done in increments of whole seconds */
1553   sqlite3 *db = (sqlite3 *)ptr;
1554   int tmout = ((sqlite3 *)ptr)->busyTimeout;
1555   UNUSED_PARAMETER(pFile);
1556   if( (count+1)*1000 > tmout ){
1557     return 0;
1558   }
1559   sqlite3OsSleep(db->pVfs, 1000000);
1560   return 1;
1561 #endif
1562 }
1563 
1564 /*
1565 ** Invoke the given busy handler.
1566 **
1567 ** This routine is called when an operation failed to acquire a
1568 ** lock on VFS file pFile.
1569 **
1570 ** If this routine returns non-zero, the lock is retried.  If it
1571 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1572 */
1573 int sqlite3InvokeBusyHandler(BusyHandler *p, sqlite3_file *pFile){
1574   int rc;
1575   if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
1576   if( p->bExtraFileArg ){
1577     /* Add an extra parameter with the pFile pointer to the end of the
1578     ** callback argument list */
1579     int (*xTra)(void*,int,sqlite3_file*);
1580     xTra = (int(*)(void*,int,sqlite3_file*))p->xBusyHandler;
1581     rc = xTra(p->pBusyArg, p->nBusy, pFile);
1582   }else{
1583     /* Legacy style busy handler callback */
1584     rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
1585   }
1586   if( rc==0 ){
1587     p->nBusy = -1;
1588   }else{
1589     p->nBusy++;
1590   }
1591   return rc;
1592 }
1593 
1594 /*
1595 ** This routine sets the busy callback for an Sqlite database to the
1596 ** given callback function with the given argument.
1597 */
1598 int sqlite3_busy_handler(
1599   sqlite3 *db,
1600   int (*xBusy)(void*,int),
1601   void *pArg
1602 ){
1603 #ifdef SQLITE_ENABLE_API_ARMOR
1604   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1605 #endif
1606   sqlite3_mutex_enter(db->mutex);
1607   db->busyHandler.xBusyHandler = xBusy;
1608   db->busyHandler.pBusyArg = pArg;
1609   db->busyHandler.nBusy = 0;
1610   db->busyHandler.bExtraFileArg = 0;
1611   db->busyTimeout = 0;
1612   sqlite3_mutex_leave(db->mutex);
1613   return SQLITE_OK;
1614 }
1615 
1616 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1617 /*
1618 ** This routine sets the progress callback for an Sqlite database to the
1619 ** given callback function with the given argument. The progress callback will
1620 ** be invoked every nOps opcodes.
1621 */
1622 void sqlite3_progress_handler(
1623   sqlite3 *db,
1624   int nOps,
1625   int (*xProgress)(void*),
1626   void *pArg
1627 ){
1628 #ifdef SQLITE_ENABLE_API_ARMOR
1629   if( !sqlite3SafetyCheckOk(db) ){
1630     (void)SQLITE_MISUSE_BKPT;
1631     return;
1632   }
1633 #endif
1634   sqlite3_mutex_enter(db->mutex);
1635   if( nOps>0 ){
1636     db->xProgress = xProgress;
1637     db->nProgressOps = (unsigned)nOps;
1638     db->pProgressArg = pArg;
1639   }else{
1640     db->xProgress = 0;
1641     db->nProgressOps = 0;
1642     db->pProgressArg = 0;
1643   }
1644   sqlite3_mutex_leave(db->mutex);
1645 }
1646 #endif
1647 
1648 
1649 /*
1650 ** This routine installs a default busy handler that waits for the
1651 ** specified number of milliseconds before returning 0.
1652 */
1653 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1654 #ifdef SQLITE_ENABLE_API_ARMOR
1655   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1656 #endif
1657   if( ms>0 ){
1658     sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
1659                              (void*)db);
1660     db->busyTimeout = ms;
1661     db->busyHandler.bExtraFileArg = 1;
1662   }else{
1663     sqlite3_busy_handler(db, 0, 0);
1664   }
1665   return SQLITE_OK;
1666 }
1667 
1668 /*
1669 ** Cause any pending operation to stop at its earliest opportunity.
1670 */
1671 void sqlite3_interrupt(sqlite3 *db){
1672 #ifdef SQLITE_ENABLE_API_ARMOR
1673   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1674     (void)SQLITE_MISUSE_BKPT;
1675     return;
1676   }
1677 #endif
1678   db->u1.isInterrupted = 1;
1679 }
1680 
1681 
1682 /*
1683 ** This function is exactly the same as sqlite3_create_function(), except
1684 ** that it is designed to be called by internal code. The difference is
1685 ** that if a malloc() fails in sqlite3_create_function(), an error code
1686 ** is returned and the mallocFailed flag cleared.
1687 */
1688 int sqlite3CreateFunc(
1689   sqlite3 *db,
1690   const char *zFunctionName,
1691   int nArg,
1692   int enc,
1693   void *pUserData,
1694   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1695   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1696   void (*xFinal)(sqlite3_context*),
1697   void (*xValue)(sqlite3_context*),
1698   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1699   FuncDestructor *pDestructor
1700 ){
1701   FuncDef *p;
1702   int nName;
1703   int extraFlags;
1704 
1705   assert( sqlite3_mutex_held(db->mutex) );
1706   assert( xValue==0 || xSFunc==0 );
1707   if( zFunctionName==0                /* Must have a valid name */
1708    || (xSFunc!=0 && xFinal!=0)        /* Not both xSFunc and xFinal */
1709    || ((xFinal==0)!=(xStep==0))       /* Both or neither of xFinal and xStep */
1710    || ((xValue==0)!=(xInverse==0))    /* Both or neither of xValue, xInverse */
1711    || (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG)
1712    || (255<(nName = sqlite3Strlen30( zFunctionName)))
1713   ){
1714     return SQLITE_MISUSE_BKPT;
1715   }
1716 
1717   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1718   extraFlags = enc &  SQLITE_DETERMINISTIC;
1719   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1720 
1721 #ifndef SQLITE_OMIT_UTF16
1722   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1723   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1724   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1725   **
1726   ** If SQLITE_ANY is specified, add three versions of the function
1727   ** to the hash table.
1728   */
1729   if( enc==SQLITE_UTF16 ){
1730     enc = SQLITE_UTF16NATIVE;
1731   }else if( enc==SQLITE_ANY ){
1732     int rc;
1733     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1734          pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1735     if( rc==SQLITE_OK ){
1736       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1737           pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1738     }
1739     if( rc!=SQLITE_OK ){
1740       return rc;
1741     }
1742     enc = SQLITE_UTF16BE;
1743   }
1744 #else
1745   enc = SQLITE_UTF8;
1746 #endif
1747 
1748   /* Check if an existing function is being overridden or deleted. If so,
1749   ** and there are active VMs, then return SQLITE_BUSY. If a function
1750   ** is being overridden/deleted but there are no active VMs, allow the
1751   ** operation to continue but invalidate all precompiled statements.
1752   */
1753   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1754   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==(u32)enc && p->nArg==nArg ){
1755     if( db->nVdbeActive ){
1756       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1757         "unable to delete/modify user-function due to active statements");
1758       assert( !db->mallocFailed );
1759       return SQLITE_BUSY;
1760     }else{
1761       sqlite3ExpirePreparedStatements(db, 0);
1762     }
1763   }
1764 
1765   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1766   assert(p || db->mallocFailed);
1767   if( !p ){
1768     return SQLITE_NOMEM_BKPT;
1769   }
1770 
1771   /* If an older version of the function with a configured destructor is
1772   ** being replaced invoke the destructor function here. */
1773   functionDestroy(db, p);
1774 
1775   if( pDestructor ){
1776     pDestructor->nRef++;
1777   }
1778   p->u.pDestructor = pDestructor;
1779   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1780   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1781   p->xSFunc = xSFunc ? xSFunc : xStep;
1782   p->xFinalize = xFinal;
1783   p->xValue = xValue;
1784   p->xInverse = xInverse;
1785   p->pUserData = pUserData;
1786   p->nArg = (u16)nArg;
1787   return SQLITE_OK;
1788 }
1789 
1790 /*
1791 ** Worker function used by utf-8 APIs that create new functions:
1792 **
1793 **    sqlite3_create_function()
1794 **    sqlite3_create_function_v2()
1795 **    sqlite3_create_window_function()
1796 */
1797 static int createFunctionApi(
1798   sqlite3 *db,
1799   const char *zFunc,
1800   int nArg,
1801   int enc,
1802   void *p,
1803   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1804   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1805   void (*xFinal)(sqlite3_context*),
1806   void (*xValue)(sqlite3_context*),
1807   void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
1808   void(*xDestroy)(void*)
1809 ){
1810   int rc = SQLITE_ERROR;
1811   FuncDestructor *pArg = 0;
1812 
1813 #ifdef SQLITE_ENABLE_API_ARMOR
1814   if( !sqlite3SafetyCheckOk(db) ){
1815     return SQLITE_MISUSE_BKPT;
1816   }
1817 #endif
1818   sqlite3_mutex_enter(db->mutex);
1819   if( xDestroy ){
1820     pArg = (FuncDestructor *)sqlite3Malloc(sizeof(FuncDestructor));
1821     if( !pArg ){
1822       sqlite3OomFault(db);
1823       xDestroy(p);
1824       goto out;
1825     }
1826     pArg->nRef = 0;
1827     pArg->xDestroy = xDestroy;
1828     pArg->pUserData = p;
1829   }
1830   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p,
1831       xSFunc, xStep, xFinal, xValue, xInverse, pArg
1832   );
1833   if( pArg && pArg->nRef==0 ){
1834     assert( rc!=SQLITE_OK );
1835     xDestroy(p);
1836     sqlite3_free(pArg);
1837   }
1838 
1839  out:
1840   rc = sqlite3ApiExit(db, rc);
1841   sqlite3_mutex_leave(db->mutex);
1842   return rc;
1843 }
1844 
1845 /*
1846 ** Create new user functions.
1847 */
1848 int sqlite3_create_function(
1849   sqlite3 *db,
1850   const char *zFunc,
1851   int nArg,
1852   int enc,
1853   void *p,
1854   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1855   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1856   void (*xFinal)(sqlite3_context*)
1857 ){
1858   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1859                                     xFinal, 0, 0, 0);
1860 }
1861 int sqlite3_create_function_v2(
1862   sqlite3 *db,
1863   const char *zFunc,
1864   int nArg,
1865   int enc,
1866   void *p,
1867   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1868   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1869   void (*xFinal)(sqlite3_context*),
1870   void (*xDestroy)(void *)
1871 ){
1872   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1873                                     xFinal, 0, 0, xDestroy);
1874 }
1875 int sqlite3_create_window_function(
1876   sqlite3 *db,
1877   const char *zFunc,
1878   int nArg,
1879   int enc,
1880   void *p,
1881   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1882   void (*xFinal)(sqlite3_context*),
1883   void (*xValue)(sqlite3_context*),
1884   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1885   void (*xDestroy)(void *)
1886 ){
1887   return createFunctionApi(db, zFunc, nArg, enc, p, 0, xStep,
1888                                     xFinal, xValue, xInverse, xDestroy);
1889 }
1890 
1891 #ifndef SQLITE_OMIT_UTF16
1892 int sqlite3_create_function16(
1893   sqlite3 *db,
1894   const void *zFunctionName,
1895   int nArg,
1896   int eTextRep,
1897   void *p,
1898   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1899   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1900   void (*xFinal)(sqlite3_context*)
1901 ){
1902   int rc;
1903   char *zFunc8;
1904 
1905 #ifdef SQLITE_ENABLE_API_ARMOR
1906   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1907 #endif
1908   sqlite3_mutex_enter(db->mutex);
1909   assert( !db->mallocFailed );
1910   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1911   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0,0,0);
1912   sqlite3DbFree(db, zFunc8);
1913   rc = sqlite3ApiExit(db, rc);
1914   sqlite3_mutex_leave(db->mutex);
1915   return rc;
1916 }
1917 #endif
1918 
1919 
1920 /*
1921 ** The following is the implementation of an SQL function that always
1922 ** fails with an error message stating that the function is used in the
1923 ** wrong context.  The sqlite3_overload_function() API might construct
1924 ** SQL function that use this routine so that the functions will exist
1925 ** for name resolution but are actually overloaded by the xFindFunction
1926 ** method of virtual tables.
1927 */
1928 static void sqlite3InvalidFunction(
1929   sqlite3_context *context,  /* The function calling context */
1930   int NotUsed,               /* Number of arguments to the function */
1931   sqlite3_value **NotUsed2   /* Value of each argument */
1932 ){
1933   const char *zName = (const char*)sqlite3_user_data(context);
1934   char *zErr;
1935   UNUSED_PARAMETER2(NotUsed, NotUsed2);
1936   zErr = sqlite3_mprintf(
1937       "unable to use function %s in the requested context", zName);
1938   sqlite3_result_error(context, zErr, -1);
1939   sqlite3_free(zErr);
1940 }
1941 
1942 /*
1943 ** Declare that a function has been overloaded by a virtual table.
1944 **
1945 ** If the function already exists as a regular global function, then
1946 ** this routine is a no-op.  If the function does not exist, then create
1947 ** a new one that always throws a run-time error.
1948 **
1949 ** When virtual tables intend to provide an overloaded function, they
1950 ** should call this routine to make sure the global function exists.
1951 ** A global function must exist in order for name resolution to work
1952 ** properly.
1953 */
1954 int sqlite3_overload_function(
1955   sqlite3 *db,
1956   const char *zName,
1957   int nArg
1958 ){
1959   int rc;
1960   char *zCopy;
1961 
1962 #ifdef SQLITE_ENABLE_API_ARMOR
1963   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1964     return SQLITE_MISUSE_BKPT;
1965   }
1966 #endif
1967   sqlite3_mutex_enter(db->mutex);
1968   rc = sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)!=0;
1969   sqlite3_mutex_leave(db->mutex);
1970   if( rc ) return SQLITE_OK;
1971   zCopy = sqlite3_mprintf(zName);
1972   if( zCopy==0 ) return SQLITE_NOMEM;
1973   return sqlite3_create_function_v2(db, zName, nArg, SQLITE_UTF8,
1974                            zCopy, sqlite3InvalidFunction, 0, 0, sqlite3_free);
1975 }
1976 
1977 #ifndef SQLITE_OMIT_TRACE
1978 /*
1979 ** Register a trace function.  The pArg from the previously registered trace
1980 ** is returned.
1981 **
1982 ** A NULL trace function means that no tracing is executes.  A non-NULL
1983 ** trace is a pointer to a function that is invoked at the start of each
1984 ** SQL statement.
1985 */
1986 #ifndef SQLITE_OMIT_DEPRECATED
1987 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1988   void *pOld;
1989 
1990 #ifdef SQLITE_ENABLE_API_ARMOR
1991   if( !sqlite3SafetyCheckOk(db) ){
1992     (void)SQLITE_MISUSE_BKPT;
1993     return 0;
1994   }
1995 #endif
1996   sqlite3_mutex_enter(db->mutex);
1997   pOld = db->pTraceArg;
1998   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
1999   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
2000   db->pTraceArg = pArg;
2001   sqlite3_mutex_leave(db->mutex);
2002   return pOld;
2003 }
2004 #endif /* SQLITE_OMIT_DEPRECATED */
2005 
2006 /* Register a trace callback using the version-2 interface.
2007 */
2008 int sqlite3_trace_v2(
2009   sqlite3 *db,                               /* Trace this connection */
2010   unsigned mTrace,                           /* Mask of events to be traced */
2011   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
2012   void *pArg                                 /* Context */
2013 ){
2014 #ifdef SQLITE_ENABLE_API_ARMOR
2015   if( !sqlite3SafetyCheckOk(db) ){
2016     return SQLITE_MISUSE_BKPT;
2017   }
2018 #endif
2019   sqlite3_mutex_enter(db->mutex);
2020   if( mTrace==0 ) xTrace = 0;
2021   if( xTrace==0 ) mTrace = 0;
2022   db->mTrace = mTrace;
2023   db->xTrace = xTrace;
2024   db->pTraceArg = pArg;
2025   sqlite3_mutex_leave(db->mutex);
2026   return SQLITE_OK;
2027 }
2028 
2029 #ifndef SQLITE_OMIT_DEPRECATED
2030 /*
2031 ** Register a profile function.  The pArg from the previously registered
2032 ** profile function is returned.
2033 **
2034 ** A NULL profile function means that no profiling is executes.  A non-NULL
2035 ** profile is a pointer to a function that is invoked at the conclusion of
2036 ** each SQL statement that is run.
2037 */
2038 void *sqlite3_profile(
2039   sqlite3 *db,
2040   void (*xProfile)(void*,const char*,sqlite_uint64),
2041   void *pArg
2042 ){
2043   void *pOld;
2044 
2045 #ifdef SQLITE_ENABLE_API_ARMOR
2046   if( !sqlite3SafetyCheckOk(db) ){
2047     (void)SQLITE_MISUSE_BKPT;
2048     return 0;
2049   }
2050 #endif
2051   sqlite3_mutex_enter(db->mutex);
2052   pOld = db->pProfileArg;
2053   db->xProfile = xProfile;
2054   db->pProfileArg = pArg;
2055   sqlite3_mutex_leave(db->mutex);
2056   return pOld;
2057 }
2058 #endif /* SQLITE_OMIT_DEPRECATED */
2059 #endif /* SQLITE_OMIT_TRACE */
2060 
2061 /*
2062 ** Register a function to be invoked when a transaction commits.
2063 ** If the invoked function returns non-zero, then the commit becomes a
2064 ** rollback.
2065 */
2066 void *sqlite3_commit_hook(
2067   sqlite3 *db,              /* Attach the hook to this database */
2068   int (*xCallback)(void*),  /* Function to invoke on each commit */
2069   void *pArg                /* Argument to the function */
2070 ){
2071   void *pOld;
2072 
2073 #ifdef SQLITE_ENABLE_API_ARMOR
2074   if( !sqlite3SafetyCheckOk(db) ){
2075     (void)SQLITE_MISUSE_BKPT;
2076     return 0;
2077   }
2078 #endif
2079   sqlite3_mutex_enter(db->mutex);
2080   pOld = db->pCommitArg;
2081   db->xCommitCallback = xCallback;
2082   db->pCommitArg = pArg;
2083   sqlite3_mutex_leave(db->mutex);
2084   return pOld;
2085 }
2086 
2087 /*
2088 ** Register a callback to be invoked each time a row is updated,
2089 ** inserted or deleted using this database connection.
2090 */
2091 void *sqlite3_update_hook(
2092   sqlite3 *db,              /* Attach the hook to this database */
2093   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
2094   void *pArg                /* Argument to the function */
2095 ){
2096   void *pRet;
2097 
2098 #ifdef SQLITE_ENABLE_API_ARMOR
2099   if( !sqlite3SafetyCheckOk(db) ){
2100     (void)SQLITE_MISUSE_BKPT;
2101     return 0;
2102   }
2103 #endif
2104   sqlite3_mutex_enter(db->mutex);
2105   pRet = db->pUpdateArg;
2106   db->xUpdateCallback = xCallback;
2107   db->pUpdateArg = pArg;
2108   sqlite3_mutex_leave(db->mutex);
2109   return pRet;
2110 }
2111 
2112 /*
2113 ** Register a callback to be invoked each time a transaction is rolled
2114 ** back by this database connection.
2115 */
2116 void *sqlite3_rollback_hook(
2117   sqlite3 *db,              /* Attach the hook to this database */
2118   void (*xCallback)(void*), /* Callback function */
2119   void *pArg                /* Argument to the function */
2120 ){
2121   void *pRet;
2122 
2123 #ifdef SQLITE_ENABLE_API_ARMOR
2124   if( !sqlite3SafetyCheckOk(db) ){
2125     (void)SQLITE_MISUSE_BKPT;
2126     return 0;
2127   }
2128 #endif
2129   sqlite3_mutex_enter(db->mutex);
2130   pRet = db->pRollbackArg;
2131   db->xRollbackCallback = xCallback;
2132   db->pRollbackArg = pArg;
2133   sqlite3_mutex_leave(db->mutex);
2134   return pRet;
2135 }
2136 
2137 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2138 /*
2139 ** Register a callback to be invoked each time a row is updated,
2140 ** inserted or deleted using this database connection.
2141 */
2142 void *sqlite3_preupdate_hook(
2143   sqlite3 *db,              /* Attach the hook to this database */
2144   void(*xCallback)(         /* Callback function */
2145     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
2146   void *pArg                /* First callback argument */
2147 ){
2148   void *pRet;
2149   sqlite3_mutex_enter(db->mutex);
2150   pRet = db->pPreUpdateArg;
2151   db->xPreUpdateCallback = xCallback;
2152   db->pPreUpdateArg = pArg;
2153   sqlite3_mutex_leave(db->mutex);
2154   return pRet;
2155 }
2156 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2157 
2158 #ifndef SQLITE_OMIT_WAL
2159 /*
2160 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2161 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2162 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2163 ** wal_autocheckpoint()).
2164 */
2165 int sqlite3WalDefaultHook(
2166   void *pClientData,     /* Argument */
2167   sqlite3 *db,           /* Connection */
2168   const char *zDb,       /* Database */
2169   int nFrame             /* Size of WAL */
2170 ){
2171   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2172     sqlite3BeginBenignMalloc();
2173     sqlite3_wal_checkpoint(db, zDb);
2174     sqlite3EndBenignMalloc();
2175   }
2176   return SQLITE_OK;
2177 }
2178 #endif /* SQLITE_OMIT_WAL */
2179 
2180 /*
2181 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2182 ** a database after committing a transaction if there are nFrame or
2183 ** more frames in the log file. Passing zero or a negative value as the
2184 ** nFrame parameter disables automatic checkpoints entirely.
2185 **
2186 ** The callback registered by this function replaces any existing callback
2187 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2188 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2189 ** configured by this function.
2190 */
2191 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2192 #ifdef SQLITE_OMIT_WAL
2193   UNUSED_PARAMETER(db);
2194   UNUSED_PARAMETER(nFrame);
2195 #else
2196 #ifdef SQLITE_ENABLE_API_ARMOR
2197   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2198 #endif
2199   if( nFrame>0 ){
2200     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2201   }else{
2202     sqlite3_wal_hook(db, 0, 0);
2203   }
2204 #endif
2205   return SQLITE_OK;
2206 }
2207 
2208 /*
2209 ** Register a callback to be invoked each time a transaction is written
2210 ** into the write-ahead-log by this database connection.
2211 */
2212 void *sqlite3_wal_hook(
2213   sqlite3 *db,                    /* Attach the hook to this db handle */
2214   int(*xCallback)(void *, sqlite3*, const char*, int),
2215   void *pArg                      /* First argument passed to xCallback() */
2216 ){
2217 #ifndef SQLITE_OMIT_WAL
2218   void *pRet;
2219 #ifdef SQLITE_ENABLE_API_ARMOR
2220   if( !sqlite3SafetyCheckOk(db) ){
2221     (void)SQLITE_MISUSE_BKPT;
2222     return 0;
2223   }
2224 #endif
2225   sqlite3_mutex_enter(db->mutex);
2226   pRet = db->pWalArg;
2227   db->xWalCallback = xCallback;
2228   db->pWalArg = pArg;
2229   sqlite3_mutex_leave(db->mutex);
2230   return pRet;
2231 #else
2232   return 0;
2233 #endif
2234 }
2235 
2236 /*
2237 ** Checkpoint database zDb.
2238 */
2239 int sqlite3_wal_checkpoint_v2(
2240   sqlite3 *db,                    /* Database handle */
2241   const char *zDb,                /* Name of attached database (or NULL) */
2242   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2243   int *pnLog,                     /* OUT: Size of WAL log in frames */
2244   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2245 ){
2246 #ifdef SQLITE_OMIT_WAL
2247   return SQLITE_OK;
2248 #else
2249   int rc;                         /* Return code */
2250   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2251 
2252 #ifdef SQLITE_ENABLE_API_ARMOR
2253   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2254 #endif
2255 
2256   /* Initialize the output variables to -1 in case an error occurs. */
2257   if( pnLog ) *pnLog = -1;
2258   if( pnCkpt ) *pnCkpt = -1;
2259 
2260   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2261   assert( SQLITE_CHECKPOINT_FULL==1 );
2262   assert( SQLITE_CHECKPOINT_RESTART==2 );
2263   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2264   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2265     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2266     ** mode: */
2267     return SQLITE_MISUSE;
2268   }
2269 
2270   sqlite3_mutex_enter(db->mutex);
2271   if( zDb && zDb[0] ){
2272     iDb = sqlite3FindDbName(db, zDb);
2273   }
2274   if( iDb<0 ){
2275     rc = SQLITE_ERROR;
2276     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2277   }else{
2278     db->busyHandler.nBusy = 0;
2279     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2280     sqlite3Error(db, rc);
2281   }
2282   rc = sqlite3ApiExit(db, rc);
2283 
2284   /* If there are no active statements, clear the interrupt flag at this
2285   ** point.  */
2286   if( db->nVdbeActive==0 ){
2287     db->u1.isInterrupted = 0;
2288   }
2289 
2290   sqlite3_mutex_leave(db->mutex);
2291   return rc;
2292 #endif
2293 }
2294 
2295 
2296 /*
2297 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2298 ** to contains a zero-length string, all attached databases are
2299 ** checkpointed.
2300 */
2301 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2302   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2303   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2304   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2305 }
2306 
2307 #ifndef SQLITE_OMIT_WAL
2308 /*
2309 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2310 ** not currently open in WAL mode.
2311 **
2312 ** If a transaction is open on the database being checkpointed, this
2313 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2314 ** an error occurs while running the checkpoint, an SQLite error code is
2315 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2316 **
2317 ** The mutex on database handle db should be held by the caller. The mutex
2318 ** associated with the specific b-tree being checkpointed is taken by
2319 ** this function while the checkpoint is running.
2320 **
2321 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2322 ** checkpointed. If an error is encountered it is returned immediately -
2323 ** no attempt is made to checkpoint any remaining databases.
2324 **
2325 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
2326 ** or TRUNCATE.
2327 */
2328 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2329   int rc = SQLITE_OK;             /* Return code */
2330   int i;                          /* Used to iterate through attached dbs */
2331   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2332 
2333   assert( sqlite3_mutex_held(db->mutex) );
2334   assert( !pnLog || *pnLog==-1 );
2335   assert( !pnCkpt || *pnCkpt==-1 );
2336 
2337   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2338     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2339       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2340       pnLog = 0;
2341       pnCkpt = 0;
2342       if( rc==SQLITE_BUSY ){
2343         bBusy = 1;
2344         rc = SQLITE_OK;
2345       }
2346     }
2347   }
2348 
2349   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2350 }
2351 #endif /* SQLITE_OMIT_WAL */
2352 
2353 /*
2354 ** This function returns true if main-memory should be used instead of
2355 ** a temporary file for transient pager files and statement journals.
2356 ** The value returned depends on the value of db->temp_store (runtime
2357 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2358 ** following table describes the relationship between these two values
2359 ** and this functions return value.
2360 **
2361 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2362 **   -----------------     --------------     ------------------------------
2363 **   0                     any                file      (return 0)
2364 **   1                     1                  file      (return 0)
2365 **   1                     2                  memory    (return 1)
2366 **   1                     0                  file      (return 0)
2367 **   2                     1                  file      (return 0)
2368 **   2                     2                  memory    (return 1)
2369 **   2                     0                  memory    (return 1)
2370 **   3                     any                memory    (return 1)
2371 */
2372 int sqlite3TempInMemory(const sqlite3 *db){
2373 #if SQLITE_TEMP_STORE==1
2374   return ( db->temp_store==2 );
2375 #endif
2376 #if SQLITE_TEMP_STORE==2
2377   return ( db->temp_store!=1 );
2378 #endif
2379 #if SQLITE_TEMP_STORE==3
2380   UNUSED_PARAMETER(db);
2381   return 1;
2382 #endif
2383 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2384   UNUSED_PARAMETER(db);
2385   return 0;
2386 #endif
2387 }
2388 
2389 /*
2390 ** Return UTF-8 encoded English language explanation of the most recent
2391 ** error.
2392 */
2393 const char *sqlite3_errmsg(sqlite3 *db){
2394   const char *z;
2395   if( !db ){
2396     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2397   }
2398   if( !sqlite3SafetyCheckSickOrOk(db) ){
2399     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2400   }
2401   sqlite3_mutex_enter(db->mutex);
2402   if( db->mallocFailed ){
2403     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2404   }else{
2405     testcase( db->pErr==0 );
2406     z = (char*)sqlite3_value_text(db->pErr);
2407     assert( !db->mallocFailed );
2408     if( z==0 ){
2409       z = sqlite3ErrStr(db->errCode);
2410     }
2411   }
2412   sqlite3_mutex_leave(db->mutex);
2413   return z;
2414 }
2415 
2416 #ifndef SQLITE_OMIT_UTF16
2417 /*
2418 ** Return UTF-16 encoded English language explanation of the most recent
2419 ** error.
2420 */
2421 const void *sqlite3_errmsg16(sqlite3 *db){
2422   static const u16 outOfMem[] = {
2423     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2424   };
2425   static const u16 misuse[] = {
2426     'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
2427     'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
2428     'm', 'i', 's', 'u', 's', 'e', 0
2429   };
2430 
2431   const void *z;
2432   if( !db ){
2433     return (void *)outOfMem;
2434   }
2435   if( !sqlite3SafetyCheckSickOrOk(db) ){
2436     return (void *)misuse;
2437   }
2438   sqlite3_mutex_enter(db->mutex);
2439   if( db->mallocFailed ){
2440     z = (void *)outOfMem;
2441   }else{
2442     z = sqlite3_value_text16(db->pErr);
2443     if( z==0 ){
2444       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2445       z = sqlite3_value_text16(db->pErr);
2446     }
2447     /* A malloc() may have failed within the call to sqlite3_value_text16()
2448     ** above. If this is the case, then the db->mallocFailed flag needs to
2449     ** be cleared before returning. Do this directly, instead of via
2450     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2451     */
2452     sqlite3OomClear(db);
2453   }
2454   sqlite3_mutex_leave(db->mutex);
2455   return z;
2456 }
2457 #endif /* SQLITE_OMIT_UTF16 */
2458 
2459 /*
2460 ** Return the most recent error code generated by an SQLite routine. If NULL is
2461 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2462 */
2463 int sqlite3_errcode(sqlite3 *db){
2464   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2465     return SQLITE_MISUSE_BKPT;
2466   }
2467   if( !db || db->mallocFailed ){
2468     return SQLITE_NOMEM_BKPT;
2469   }
2470   return db->errCode & db->errMask;
2471 }
2472 int sqlite3_extended_errcode(sqlite3 *db){
2473   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2474     return SQLITE_MISUSE_BKPT;
2475   }
2476   if( !db || db->mallocFailed ){
2477     return SQLITE_NOMEM_BKPT;
2478   }
2479   return db->errCode;
2480 }
2481 int sqlite3_system_errno(sqlite3 *db){
2482   return db ? db->iSysErrno : 0;
2483 }
2484 
2485 /*
2486 ** Return a string that describes the kind of error specified in the
2487 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2488 ** function.
2489 */
2490 const char *sqlite3_errstr(int rc){
2491   return sqlite3ErrStr(rc);
2492 }
2493 
2494 /*
2495 ** Create a new collating function for database "db".  The name is zName
2496 ** and the encoding is enc.
2497 */
2498 static int createCollation(
2499   sqlite3* db,
2500   const char *zName,
2501   u8 enc,
2502   void* pCtx,
2503   int(*xCompare)(void*,int,const void*,int,const void*),
2504   void(*xDel)(void*)
2505 ){
2506   CollSeq *pColl;
2507   int enc2;
2508 
2509   assert( sqlite3_mutex_held(db->mutex) );
2510 
2511   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2512   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2513   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2514   */
2515   enc2 = enc;
2516   testcase( enc2==SQLITE_UTF16 );
2517   testcase( enc2==SQLITE_UTF16_ALIGNED );
2518   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2519     enc2 = SQLITE_UTF16NATIVE;
2520   }
2521   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2522     return SQLITE_MISUSE_BKPT;
2523   }
2524 
2525   /* Check if this call is removing or replacing an existing collation
2526   ** sequence. If so, and there are active VMs, return busy. If there
2527   ** are no active VMs, invalidate any pre-compiled statements.
2528   */
2529   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2530   if( pColl && pColl->xCmp ){
2531     if( db->nVdbeActive ){
2532       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2533         "unable to delete/modify collation sequence due to active statements");
2534       return SQLITE_BUSY;
2535     }
2536     sqlite3ExpirePreparedStatements(db, 0);
2537 
2538     /* If collation sequence pColl was created directly by a call to
2539     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2540     ** then any copies made by synthCollSeq() need to be invalidated.
2541     ** Also, collation destructor - CollSeq.xDel() - function may need
2542     ** to be called.
2543     */
2544     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2545       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2546       int j;
2547       for(j=0; j<3; j++){
2548         CollSeq *p = &aColl[j];
2549         if( p->enc==pColl->enc ){
2550           if( p->xDel ){
2551             p->xDel(p->pUser);
2552           }
2553           p->xCmp = 0;
2554         }
2555       }
2556     }
2557   }
2558 
2559   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2560   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2561   pColl->xCmp = xCompare;
2562   pColl->pUser = pCtx;
2563   pColl->xDel = xDel;
2564   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2565   sqlite3Error(db, SQLITE_OK);
2566   return SQLITE_OK;
2567 }
2568 
2569 
2570 /*
2571 ** This array defines hard upper bounds on limit values.  The
2572 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2573 ** #defines in sqlite3.h.
2574 */
2575 static const int aHardLimit[] = {
2576   SQLITE_MAX_LENGTH,
2577   SQLITE_MAX_SQL_LENGTH,
2578   SQLITE_MAX_COLUMN,
2579   SQLITE_MAX_EXPR_DEPTH,
2580   SQLITE_MAX_COMPOUND_SELECT,
2581   SQLITE_MAX_VDBE_OP,
2582   SQLITE_MAX_FUNCTION_ARG,
2583   SQLITE_MAX_ATTACHED,
2584   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2585   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2586   SQLITE_MAX_TRIGGER_DEPTH,
2587   SQLITE_MAX_WORKER_THREADS,
2588 };
2589 
2590 /*
2591 ** Make sure the hard limits are set to reasonable values
2592 */
2593 #if SQLITE_MAX_LENGTH<100
2594 # error SQLITE_MAX_LENGTH must be at least 100
2595 #endif
2596 #if SQLITE_MAX_SQL_LENGTH<100
2597 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2598 #endif
2599 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2600 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2601 #endif
2602 #if SQLITE_MAX_COMPOUND_SELECT<2
2603 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2604 #endif
2605 #if SQLITE_MAX_VDBE_OP<40
2606 # error SQLITE_MAX_VDBE_OP must be at least 40
2607 #endif
2608 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2609 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2610 #endif
2611 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2612 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2613 #endif
2614 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2615 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2616 #endif
2617 #if SQLITE_MAX_COLUMN>32767
2618 # error SQLITE_MAX_COLUMN must not exceed 32767
2619 #endif
2620 #if SQLITE_MAX_TRIGGER_DEPTH<1
2621 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2622 #endif
2623 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2624 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2625 #endif
2626 
2627 
2628 /*
2629 ** Change the value of a limit.  Report the old value.
2630 ** If an invalid limit index is supplied, report -1.
2631 ** Make no changes but still report the old value if the
2632 ** new limit is negative.
2633 **
2634 ** A new lower limit does not shrink existing constructs.
2635 ** It merely prevents new constructs that exceed the limit
2636 ** from forming.
2637 */
2638 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2639   int oldLimit;
2640 
2641 #ifdef SQLITE_ENABLE_API_ARMOR
2642   if( !sqlite3SafetyCheckOk(db) ){
2643     (void)SQLITE_MISUSE_BKPT;
2644     return -1;
2645   }
2646 #endif
2647 
2648   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2649   ** there is a hard upper bound set at compile-time by a C preprocessor
2650   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2651   ** "_MAX_".)
2652   */
2653   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2654   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2655   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2656   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2657   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2658   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2659   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2660   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2661   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2662                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2663   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2664   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2665   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2666   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2667 
2668 
2669   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2670     return -1;
2671   }
2672   oldLimit = db->aLimit[limitId];
2673   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2674     if( newLimit>aHardLimit[limitId] ){
2675       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2676     }
2677     db->aLimit[limitId] = newLimit;
2678   }
2679   return oldLimit;                     /* IMP: R-53341-35419 */
2680 }
2681 
2682 /*
2683 ** This function is used to parse both URIs and non-URI filenames passed by the
2684 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2685 ** URIs specified as part of ATTACH statements.
2686 **
2687 ** The first argument to this function is the name of the VFS to use (or
2688 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2689 ** query parameter. The second argument contains the URI (or non-URI filename)
2690 ** itself. When this function is called the *pFlags variable should contain
2691 ** the default flags to open the database handle with. The value stored in
2692 ** *pFlags may be updated before returning if the URI filename contains
2693 ** "cache=xxx" or "mode=xxx" query parameters.
2694 **
2695 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2696 ** the VFS that should be used to open the database file. *pzFile is set to
2697 ** point to a buffer containing the name of the file to open. It is the
2698 ** responsibility of the caller to eventually call sqlite3_free() to release
2699 ** this buffer.
2700 **
2701 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2702 ** may be set to point to a buffer containing an English language error
2703 ** message. It is the responsibility of the caller to eventually release
2704 ** this buffer by calling sqlite3_free().
2705 */
2706 int sqlite3ParseUri(
2707   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2708   const char *zUri,               /* Nul-terminated URI to parse */
2709   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2710   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2711   char **pzFile,                  /* OUT: Filename component of URI */
2712   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2713 ){
2714   int rc = SQLITE_OK;
2715   unsigned int flags = *pFlags;
2716   const char *zVfs = zDefaultVfs;
2717   char *zFile;
2718   char c;
2719   int nUri = sqlite3Strlen30(zUri);
2720 
2721   assert( *pzErrMsg==0 );
2722 
2723   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2724             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2725    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2726   ){
2727     char *zOpt;
2728     int eState;                   /* Parser state when parsing URI */
2729     int iIn;                      /* Input character index */
2730     int iOut = 0;                 /* Output character index */
2731     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2732 
2733     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2734     ** method that there may be extra parameters following the file-name.  */
2735     flags |= SQLITE_OPEN_URI;
2736 
2737     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2738     zFile = sqlite3_malloc64(nByte);
2739     if( !zFile ) return SQLITE_NOMEM_BKPT;
2740 
2741     iIn = 5;
2742 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2743     if( strncmp(zUri+5, "///", 3)==0 ){
2744       iIn = 7;
2745       /* The following condition causes URIs with five leading / characters
2746       ** like file://///host/path to be converted into UNCs like //host/path.
2747       ** The correct URI for that UNC has only two or four leading / characters
2748       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2749       ** common error, we are told, so we handle it as a special case. */
2750       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2751     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2752       iIn = 16;
2753     }
2754 #else
2755     /* Discard the scheme and authority segments of the URI. */
2756     if( zUri[5]=='/' && zUri[6]=='/' ){
2757       iIn = 7;
2758       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2759       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2760         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2761             iIn-7, &zUri[7]);
2762         rc = SQLITE_ERROR;
2763         goto parse_uri_out;
2764       }
2765     }
2766 #endif
2767 
2768     /* Copy the filename and any query parameters into the zFile buffer.
2769     ** Decode %HH escape codes along the way.
2770     **
2771     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2772     ** on the parsing context. As follows:
2773     **
2774     **   0: Parsing file-name.
2775     **   1: Parsing name section of a name=value query parameter.
2776     **   2: Parsing value section of a name=value query parameter.
2777     */
2778     eState = 0;
2779     while( (c = zUri[iIn])!=0 && c!='#' ){
2780       iIn++;
2781       if( c=='%'
2782        && sqlite3Isxdigit(zUri[iIn])
2783        && sqlite3Isxdigit(zUri[iIn+1])
2784       ){
2785         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2786         octet += sqlite3HexToInt(zUri[iIn++]);
2787 
2788         assert( octet>=0 && octet<256 );
2789         if( octet==0 ){
2790 #ifndef SQLITE_ENABLE_URI_00_ERROR
2791           /* This branch is taken when "%00" appears within the URI. In this
2792           ** case we ignore all text in the remainder of the path, name or
2793           ** value currently being parsed. So ignore the current character
2794           ** and skip to the next "?", "=" or "&", as appropriate. */
2795           while( (c = zUri[iIn])!=0 && c!='#'
2796               && (eState!=0 || c!='?')
2797               && (eState!=1 || (c!='=' && c!='&'))
2798               && (eState!=2 || c!='&')
2799           ){
2800             iIn++;
2801           }
2802           continue;
2803 #else
2804           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2805           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2806           rc = SQLITE_ERROR;
2807           goto parse_uri_out;
2808 #endif
2809         }
2810         c = octet;
2811       }else if( eState==1 && (c=='&' || c=='=') ){
2812         if( zFile[iOut-1]==0 ){
2813           /* An empty option name. Ignore this option altogether. */
2814           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2815           continue;
2816         }
2817         if( c=='&' ){
2818           zFile[iOut++] = '\0';
2819         }else{
2820           eState = 2;
2821         }
2822         c = 0;
2823       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2824         c = 0;
2825         eState = 1;
2826       }
2827       zFile[iOut++] = c;
2828     }
2829     if( eState==1 ) zFile[iOut++] = '\0';
2830     zFile[iOut++] = '\0';
2831     zFile[iOut++] = '\0';
2832 
2833     /* Check if there were any options specified that should be interpreted
2834     ** here. Options that are interpreted here include "vfs" and those that
2835     ** correspond to flags that may be passed to the sqlite3_open_v2()
2836     ** method. */
2837     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2838     while( zOpt[0] ){
2839       int nOpt = sqlite3Strlen30(zOpt);
2840       char *zVal = &zOpt[nOpt+1];
2841       int nVal = sqlite3Strlen30(zVal);
2842 
2843       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2844         zVfs = zVal;
2845       }else{
2846         struct OpenMode {
2847           const char *z;
2848           int mode;
2849         } *aMode = 0;
2850         char *zModeType = 0;
2851         int mask = 0;
2852         int limit = 0;
2853 
2854         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2855           static struct OpenMode aCacheMode[] = {
2856             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2857             { "private", SQLITE_OPEN_PRIVATECACHE },
2858             { 0, 0 }
2859           };
2860 
2861           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2862           aMode = aCacheMode;
2863           limit = mask;
2864           zModeType = "cache";
2865         }
2866         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2867           static struct OpenMode aOpenMode[] = {
2868             { "ro",  SQLITE_OPEN_READONLY },
2869             { "rw",  SQLITE_OPEN_READWRITE },
2870             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2871             { "memory", SQLITE_OPEN_MEMORY },
2872             { 0, 0 }
2873           };
2874 
2875           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2876                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2877           aMode = aOpenMode;
2878           limit = mask & flags;
2879           zModeType = "access";
2880         }
2881 
2882         if( aMode ){
2883           int i;
2884           int mode = 0;
2885           for(i=0; aMode[i].z; i++){
2886             const char *z = aMode[i].z;
2887             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2888               mode = aMode[i].mode;
2889               break;
2890             }
2891           }
2892           if( mode==0 ){
2893             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2894             rc = SQLITE_ERROR;
2895             goto parse_uri_out;
2896           }
2897           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2898             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2899                                         zModeType, zVal);
2900             rc = SQLITE_PERM;
2901             goto parse_uri_out;
2902           }
2903           flags = (flags & ~mask) | mode;
2904         }
2905       }
2906 
2907       zOpt = &zVal[nVal+1];
2908     }
2909 
2910   }else{
2911     zFile = sqlite3_malloc64(nUri+2);
2912     if( !zFile ) return SQLITE_NOMEM_BKPT;
2913     if( nUri ){
2914       memcpy(zFile, zUri, nUri);
2915     }
2916     zFile[nUri] = '\0';
2917     zFile[nUri+1] = '\0';
2918     flags &= ~SQLITE_OPEN_URI;
2919   }
2920 
2921   *ppVfs = sqlite3_vfs_find(zVfs);
2922   if( *ppVfs==0 ){
2923     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2924     rc = SQLITE_ERROR;
2925   }
2926  parse_uri_out:
2927   if( rc!=SQLITE_OK ){
2928     sqlite3_free(zFile);
2929     zFile = 0;
2930   }
2931   *pFlags = flags;
2932   *pzFile = zFile;
2933   return rc;
2934 }
2935 
2936 
2937 /*
2938 ** This routine does the work of opening a database on behalf of
2939 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2940 ** is UTF-8 encoded.
2941 */
2942 static int openDatabase(
2943   const char *zFilename, /* Database filename UTF-8 encoded */
2944   sqlite3 **ppDb,        /* OUT: Returned database handle */
2945   unsigned int flags,    /* Operational flags */
2946   const char *zVfs       /* Name of the VFS to use */
2947 ){
2948   sqlite3 *db;                    /* Store allocated handle here */
2949   int rc;                         /* Return code */
2950   int isThreadsafe;               /* True for threadsafe connections */
2951   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2952   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2953 
2954 #ifdef SQLITE_ENABLE_API_ARMOR
2955   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2956 #endif
2957   *ppDb = 0;
2958 #ifndef SQLITE_OMIT_AUTOINIT
2959   rc = sqlite3_initialize();
2960   if( rc ) return rc;
2961 #endif
2962 
2963   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2964     isThreadsafe = 0;
2965   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2966     isThreadsafe = 0;
2967   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2968     isThreadsafe = 1;
2969   }else{
2970     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2971   }
2972 
2973   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2974     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2975   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2976     flags |= SQLITE_OPEN_SHAREDCACHE;
2977   }
2978 
2979   /* Remove harmful bits from the flags parameter
2980   **
2981   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2982   ** dealt with in the previous code block.  Besides these, the only
2983   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2984   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2985   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2986   ** off all other flags.
2987   */
2988   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2989                SQLITE_OPEN_EXCLUSIVE |
2990                SQLITE_OPEN_MAIN_DB |
2991                SQLITE_OPEN_TEMP_DB |
2992                SQLITE_OPEN_TRANSIENT_DB |
2993                SQLITE_OPEN_MAIN_JOURNAL |
2994                SQLITE_OPEN_TEMP_JOURNAL |
2995                SQLITE_OPEN_SUBJOURNAL |
2996                SQLITE_OPEN_MASTER_JOURNAL |
2997                SQLITE_OPEN_NOMUTEX |
2998                SQLITE_OPEN_FULLMUTEX |
2999                SQLITE_OPEN_WAL
3000              );
3001 
3002   /* Allocate the sqlite data structure */
3003   db = sqlite3MallocZero( sizeof(sqlite3) );
3004   if( db==0 ) goto opendb_out;
3005   if( isThreadsafe
3006 #ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
3007    || sqlite3GlobalConfig.bCoreMutex
3008 #endif
3009   ){
3010     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
3011     if( db->mutex==0 ){
3012       sqlite3_free(db);
3013       db = 0;
3014       goto opendb_out;
3015     }
3016     if( isThreadsafe==0 ){
3017       sqlite3MutexWarnOnContention(db->mutex);
3018     }
3019   }
3020   sqlite3_mutex_enter(db->mutex);
3021   db->errMask = 0xff;
3022   db->nDb = 2;
3023   db->magic = SQLITE_MAGIC_BUSY;
3024   db->aDb = db->aDbStatic;
3025   db->lookaside.bDisable = 1;
3026 
3027   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
3028   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
3029   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
3030   db->autoCommit = 1;
3031   db->nextAutovac = -1;
3032   db->szMmap = sqlite3GlobalConfig.szMmap;
3033   db->nextPagesize = 0;
3034   db->nMaxSorterMmap = 0x7FFFFFFF;
3035   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
3036 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
3037                  | SQLITE_AutoIndex
3038 #endif
3039 #if SQLITE_DEFAULT_CKPTFULLFSYNC
3040                  | SQLITE_CkptFullFSync
3041 #endif
3042 #if SQLITE_DEFAULT_FILE_FORMAT<4
3043                  | SQLITE_LegacyFileFmt
3044 #endif
3045 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
3046                  | SQLITE_LoadExtension
3047 #endif
3048 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
3049                  | SQLITE_RecTriggers
3050 #endif
3051 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
3052                  | SQLITE_ForeignKeys
3053 #endif
3054 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
3055                  | SQLITE_ReverseOrder
3056 #endif
3057 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
3058                  | SQLITE_CellSizeCk
3059 #endif
3060 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
3061                  | SQLITE_Fts3Tokenizer
3062 #endif
3063 #if defined(SQLITE_ENABLE_QPSG)
3064                  | SQLITE_EnableQPSG
3065 #endif
3066 #if defined(SQLITE_DEFAULT_DEFENSIVE)
3067                  | SQLITE_Defensive
3068 #endif
3069       ;
3070   sqlite3HashInit(&db->aCollSeq);
3071 #ifndef SQLITE_OMIT_VIRTUALTABLE
3072   sqlite3HashInit(&db->aModule);
3073 #endif
3074 
3075   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
3076   ** and UTF-16, so add a version for each to avoid any unnecessary
3077   ** conversions. The only error that can occur here is a malloc() failure.
3078   **
3079   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
3080   ** functions:
3081   */
3082   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
3083   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
3084   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
3085   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
3086   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
3087   if( db->mallocFailed ){
3088     goto opendb_out;
3089   }
3090   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
3091   ** strings is BINARY.
3092   */
3093   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
3094   assert( db->pDfltColl!=0 );
3095 
3096   /* Parse the filename/URI argument
3097   **
3098   ** Only allow sensible combinations of bits in the flags argument.
3099   ** Throw an error if any non-sense combination is used.  If we
3100   ** do not block illegal combinations here, it could trigger
3101   ** assert() statements in deeper layers.  Sensible combinations
3102   ** are:
3103   **
3104   **  1:  SQLITE_OPEN_READONLY
3105   **  2:  SQLITE_OPEN_READWRITE
3106   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
3107   */
3108   db->openFlags = flags;
3109   assert( SQLITE_OPEN_READONLY  == 0x01 );
3110   assert( SQLITE_OPEN_READWRITE == 0x02 );
3111   assert( SQLITE_OPEN_CREATE    == 0x04 );
3112   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
3113   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
3114   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
3115   if( ((1<<(flags&7)) & 0x46)==0 ){
3116     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
3117   }else{
3118     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
3119   }
3120   if( rc!=SQLITE_OK ){
3121     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
3122     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
3123     sqlite3_free(zErrMsg);
3124     goto opendb_out;
3125   }
3126 
3127   /* Open the backend database driver */
3128   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
3129                         flags | SQLITE_OPEN_MAIN_DB);
3130   if( rc!=SQLITE_OK ){
3131     if( rc==SQLITE_IOERR_NOMEM ){
3132       rc = SQLITE_NOMEM_BKPT;
3133     }
3134     sqlite3Error(db, rc);
3135     goto opendb_out;
3136   }
3137   sqlite3BtreeEnter(db->aDb[0].pBt);
3138   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
3139   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
3140   sqlite3BtreeLeave(db->aDb[0].pBt);
3141   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
3142 
3143   /* The default safety_level for the main database is FULL; for the temp
3144   ** database it is OFF. This matches the pager layer defaults.
3145   */
3146   db->aDb[0].zDbSName = "main";
3147   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
3148   db->aDb[1].zDbSName = "temp";
3149   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
3150 
3151   db->magic = SQLITE_MAGIC_OPEN;
3152   if( db->mallocFailed ){
3153     goto opendb_out;
3154   }
3155 
3156   /* Register all built-in functions, but do not attempt to read the
3157   ** database schema yet. This is delayed until the first time the database
3158   ** is accessed.
3159   */
3160   sqlite3Error(db, SQLITE_OK);
3161   sqlite3RegisterPerConnectionBuiltinFunctions(db);
3162   rc = sqlite3_errcode(db);
3163 
3164 #ifdef SQLITE_ENABLE_FTS5
3165   /* Register any built-in FTS5 module before loading the automatic
3166   ** extensions. This allows automatic extensions to register FTS5
3167   ** tokenizers and auxiliary functions.  */
3168   if( !db->mallocFailed && rc==SQLITE_OK ){
3169     rc = sqlite3Fts5Init(db);
3170   }
3171 #endif
3172 
3173   /* Load automatic extensions - extensions that have been registered
3174   ** using the sqlite3_automatic_extension() API.
3175   */
3176   if( rc==SQLITE_OK ){
3177     sqlite3AutoLoadExtensions(db);
3178     rc = sqlite3_errcode(db);
3179     if( rc!=SQLITE_OK ){
3180       goto opendb_out;
3181     }
3182   }
3183 
3184 #ifdef SQLITE_ENABLE_FTS1
3185   if( !db->mallocFailed ){
3186     extern int sqlite3Fts1Init(sqlite3*);
3187     rc = sqlite3Fts1Init(db);
3188   }
3189 #endif
3190 
3191 #ifdef SQLITE_ENABLE_FTS2
3192   if( !db->mallocFailed && rc==SQLITE_OK ){
3193     extern int sqlite3Fts2Init(sqlite3*);
3194     rc = sqlite3Fts2Init(db);
3195   }
3196 #endif
3197 
3198 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3199   if( !db->mallocFailed && rc==SQLITE_OK ){
3200     rc = sqlite3Fts3Init(db);
3201   }
3202 #endif
3203 
3204 #if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
3205   if( !db->mallocFailed && rc==SQLITE_OK ){
3206     rc = sqlite3IcuInit(db);
3207   }
3208 #endif
3209 
3210 #ifdef SQLITE_ENABLE_RTREE
3211   if( !db->mallocFailed && rc==SQLITE_OK){
3212     rc = sqlite3RtreeInit(db);
3213   }
3214 #endif
3215 
3216 #ifdef SQLITE_ENABLE_DBPAGE_VTAB
3217   if( !db->mallocFailed && rc==SQLITE_OK){
3218     rc = sqlite3DbpageRegister(db);
3219   }
3220 #endif
3221 
3222 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3223   if( !db->mallocFailed && rc==SQLITE_OK){
3224     rc = sqlite3DbstatRegister(db);
3225   }
3226 #endif
3227 
3228 #ifdef SQLITE_ENABLE_JSON1
3229   if( !db->mallocFailed && rc==SQLITE_OK){
3230     rc = sqlite3Json1Init(db);
3231   }
3232 #endif
3233 
3234 #ifdef SQLITE_ENABLE_STMTVTAB
3235   if( !db->mallocFailed && rc==SQLITE_OK){
3236     rc = sqlite3StmtVtabInit(db);
3237   }
3238 #endif
3239 
3240   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3241   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3242   ** mode.  Doing nothing at all also makes NORMAL the default.
3243   */
3244 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3245   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3246   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3247                           SQLITE_DEFAULT_LOCKING_MODE);
3248 #endif
3249 
3250   if( rc ) sqlite3Error(db, rc);
3251 
3252   /* Enable the lookaside-malloc subsystem */
3253   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3254                         sqlite3GlobalConfig.nLookaside);
3255 
3256   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3257 
3258 opendb_out:
3259   if( db ){
3260     assert( db->mutex!=0 || isThreadsafe==0
3261            || sqlite3GlobalConfig.bFullMutex==0 );
3262     sqlite3_mutex_leave(db->mutex);
3263   }
3264   rc = sqlite3_errcode(db);
3265   assert( db!=0 || rc==SQLITE_NOMEM );
3266   if( rc==SQLITE_NOMEM ){
3267     sqlite3_close(db);
3268     db = 0;
3269   }else if( rc!=SQLITE_OK ){
3270     db->magic = SQLITE_MAGIC_SICK;
3271   }
3272   *ppDb = db;
3273 #ifdef SQLITE_ENABLE_SQLLOG
3274   if( sqlite3GlobalConfig.xSqllog ){
3275     /* Opening a db handle. Fourth parameter is passed 0. */
3276     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3277     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3278   }
3279 #endif
3280 #if defined(SQLITE_HAS_CODEC)
3281   if( rc==SQLITE_OK ){
3282     const char *zKey;
3283     if( (zKey = sqlite3_uri_parameter(zOpen, "hexkey"))!=0 && zKey[0] ){
3284       u8 iByte;
3285       int i;
3286       char zDecoded[40];
3287       for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
3288         iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
3289         if( (i&1)!=0 ) zDecoded[i/2] = iByte;
3290       }
3291       sqlite3_key_v2(db, 0, zDecoded, i/2);
3292     }else if( (zKey = sqlite3_uri_parameter(zOpen, "key"))!=0 ){
3293       sqlite3_key_v2(db, 0, zKey, sqlite3Strlen30(zKey));
3294     }
3295   }
3296 #endif
3297   sqlite3_free(zOpen);
3298   return rc & 0xff;
3299 }
3300 
3301 /*
3302 ** Open a new database handle.
3303 */
3304 int sqlite3_open(
3305   const char *zFilename,
3306   sqlite3 **ppDb
3307 ){
3308   return openDatabase(zFilename, ppDb,
3309                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3310 }
3311 int sqlite3_open_v2(
3312   const char *filename,   /* Database filename (UTF-8) */
3313   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3314   int flags,              /* Flags */
3315   const char *zVfs        /* Name of VFS module to use */
3316 ){
3317   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3318 }
3319 
3320 #ifndef SQLITE_OMIT_UTF16
3321 /*
3322 ** Open a new database handle.
3323 */
3324 int sqlite3_open16(
3325   const void *zFilename,
3326   sqlite3 **ppDb
3327 ){
3328   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3329   sqlite3_value *pVal;
3330   int rc;
3331 
3332 #ifdef SQLITE_ENABLE_API_ARMOR
3333   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3334 #endif
3335   *ppDb = 0;
3336 #ifndef SQLITE_OMIT_AUTOINIT
3337   rc = sqlite3_initialize();
3338   if( rc ) return rc;
3339 #endif
3340   if( zFilename==0 ) zFilename = "\000\000";
3341   pVal = sqlite3ValueNew(0);
3342   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3343   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3344   if( zFilename8 ){
3345     rc = openDatabase(zFilename8, ppDb,
3346                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3347     assert( *ppDb || rc==SQLITE_NOMEM );
3348     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3349       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3350     }
3351   }else{
3352     rc = SQLITE_NOMEM_BKPT;
3353   }
3354   sqlite3ValueFree(pVal);
3355 
3356   return rc & 0xff;
3357 }
3358 #endif /* SQLITE_OMIT_UTF16 */
3359 
3360 /*
3361 ** Register a new collation sequence with the database handle db.
3362 */
3363 int sqlite3_create_collation(
3364   sqlite3* db,
3365   const char *zName,
3366   int enc,
3367   void* pCtx,
3368   int(*xCompare)(void*,int,const void*,int,const void*)
3369 ){
3370   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3371 }
3372 
3373 /*
3374 ** Register a new collation sequence with the database handle db.
3375 */
3376 int sqlite3_create_collation_v2(
3377   sqlite3* db,
3378   const char *zName,
3379   int enc,
3380   void* pCtx,
3381   int(*xCompare)(void*,int,const void*,int,const void*),
3382   void(*xDel)(void*)
3383 ){
3384   int rc;
3385 
3386 #ifdef SQLITE_ENABLE_API_ARMOR
3387   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3388 #endif
3389   sqlite3_mutex_enter(db->mutex);
3390   assert( !db->mallocFailed );
3391   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3392   rc = sqlite3ApiExit(db, rc);
3393   sqlite3_mutex_leave(db->mutex);
3394   return rc;
3395 }
3396 
3397 #ifndef SQLITE_OMIT_UTF16
3398 /*
3399 ** Register a new collation sequence with the database handle db.
3400 */
3401 int sqlite3_create_collation16(
3402   sqlite3* db,
3403   const void *zName,
3404   int enc,
3405   void* pCtx,
3406   int(*xCompare)(void*,int,const void*,int,const void*)
3407 ){
3408   int rc = SQLITE_OK;
3409   char *zName8;
3410 
3411 #ifdef SQLITE_ENABLE_API_ARMOR
3412   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3413 #endif
3414   sqlite3_mutex_enter(db->mutex);
3415   assert( !db->mallocFailed );
3416   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3417   if( zName8 ){
3418     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3419     sqlite3DbFree(db, zName8);
3420   }
3421   rc = sqlite3ApiExit(db, rc);
3422   sqlite3_mutex_leave(db->mutex);
3423   return rc;
3424 }
3425 #endif /* SQLITE_OMIT_UTF16 */
3426 
3427 /*
3428 ** Register a collation sequence factory callback with the database handle
3429 ** db. Replace any previously installed collation sequence factory.
3430 */
3431 int sqlite3_collation_needed(
3432   sqlite3 *db,
3433   void *pCollNeededArg,
3434   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3435 ){
3436 #ifdef SQLITE_ENABLE_API_ARMOR
3437   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3438 #endif
3439   sqlite3_mutex_enter(db->mutex);
3440   db->xCollNeeded = xCollNeeded;
3441   db->xCollNeeded16 = 0;
3442   db->pCollNeededArg = pCollNeededArg;
3443   sqlite3_mutex_leave(db->mutex);
3444   return SQLITE_OK;
3445 }
3446 
3447 #ifndef SQLITE_OMIT_UTF16
3448 /*
3449 ** Register a collation sequence factory callback with the database handle
3450 ** db. Replace any previously installed collation sequence factory.
3451 */
3452 int sqlite3_collation_needed16(
3453   sqlite3 *db,
3454   void *pCollNeededArg,
3455   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3456 ){
3457 #ifdef SQLITE_ENABLE_API_ARMOR
3458   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3459 #endif
3460   sqlite3_mutex_enter(db->mutex);
3461   db->xCollNeeded = 0;
3462   db->xCollNeeded16 = xCollNeeded16;
3463   db->pCollNeededArg = pCollNeededArg;
3464   sqlite3_mutex_leave(db->mutex);
3465   return SQLITE_OK;
3466 }
3467 #endif /* SQLITE_OMIT_UTF16 */
3468 
3469 #ifndef SQLITE_OMIT_DEPRECATED
3470 /*
3471 ** This function is now an anachronism. It used to be used to recover from a
3472 ** malloc() failure, but SQLite now does this automatically.
3473 */
3474 int sqlite3_global_recover(void){
3475   return SQLITE_OK;
3476 }
3477 #endif
3478 
3479 /*
3480 ** Test to see whether or not the database connection is in autocommit
3481 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3482 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3483 ** by the next COMMIT or ROLLBACK.
3484 */
3485 int sqlite3_get_autocommit(sqlite3 *db){
3486 #ifdef SQLITE_ENABLE_API_ARMOR
3487   if( !sqlite3SafetyCheckOk(db) ){
3488     (void)SQLITE_MISUSE_BKPT;
3489     return 0;
3490   }
3491 #endif
3492   return db->autoCommit;
3493 }
3494 
3495 /*
3496 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3497 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3498 ** constants.  They serve two purposes:
3499 **
3500 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3501 **       to detect when version error conditions occurs.
3502 **
3503 **   2.  Invoke sqlite3_log() to provide the source code location where
3504 **       a low-level error is first detected.
3505 */
3506 int sqlite3ReportError(int iErr, int lineno, const char *zType){
3507   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3508               zType, lineno, 20+sqlite3_sourceid());
3509   return iErr;
3510 }
3511 int sqlite3CorruptError(int lineno){
3512   testcase( sqlite3GlobalConfig.xLog!=0 );
3513   return sqlite3ReportError(SQLITE_CORRUPT, lineno, "database corruption");
3514 }
3515 int sqlite3MisuseError(int lineno){
3516   testcase( sqlite3GlobalConfig.xLog!=0 );
3517   return sqlite3ReportError(SQLITE_MISUSE, lineno, "misuse");
3518 }
3519 int sqlite3CantopenError(int lineno){
3520   testcase( sqlite3GlobalConfig.xLog!=0 );
3521   return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3522 }
3523 #ifdef SQLITE_DEBUG
3524 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3525   char zMsg[100];
3526   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3527   testcase( sqlite3GlobalConfig.xLog!=0 );
3528   return sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
3529 }
3530 int sqlite3NomemError(int lineno){
3531   testcase( sqlite3GlobalConfig.xLog!=0 );
3532   return sqlite3ReportError(SQLITE_NOMEM, lineno, "OOM");
3533 }
3534 int sqlite3IoerrnomemError(int lineno){
3535   testcase( sqlite3GlobalConfig.xLog!=0 );
3536   return sqlite3ReportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3537 }
3538 #endif
3539 
3540 #ifndef SQLITE_OMIT_DEPRECATED
3541 /*
3542 ** This is a convenience routine that makes sure that all thread-specific
3543 ** data for this thread has been deallocated.
3544 **
3545 ** SQLite no longer uses thread-specific data so this routine is now a
3546 ** no-op.  It is retained for historical compatibility.
3547 */
3548 void sqlite3_thread_cleanup(void){
3549 }
3550 #endif
3551 
3552 /*
3553 ** Return meta information about a specific column of a database table.
3554 ** See comment in sqlite3.h (sqlite.h.in) for details.
3555 */
3556 int sqlite3_table_column_metadata(
3557   sqlite3 *db,                /* Connection handle */
3558   const char *zDbName,        /* Database name or NULL */
3559   const char *zTableName,     /* Table name */
3560   const char *zColumnName,    /* Column name */
3561   char const **pzDataType,    /* OUTPUT: Declared data type */
3562   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3563   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3564   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3565   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3566 ){
3567   int rc;
3568   char *zErrMsg = 0;
3569   Table *pTab = 0;
3570   Column *pCol = 0;
3571   int iCol = 0;
3572   char const *zDataType = 0;
3573   char const *zCollSeq = 0;
3574   int notnull = 0;
3575   int primarykey = 0;
3576   int autoinc = 0;
3577 
3578 
3579 #ifdef SQLITE_ENABLE_API_ARMOR
3580   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3581     return SQLITE_MISUSE_BKPT;
3582   }
3583 #endif
3584 
3585   /* Ensure the database schema has been loaded */
3586   sqlite3_mutex_enter(db->mutex);
3587   sqlite3BtreeEnterAll(db);
3588   rc = sqlite3Init(db, &zErrMsg);
3589   if( SQLITE_OK!=rc ){
3590     goto error_out;
3591   }
3592 
3593   /* Locate the table in question */
3594   pTab = sqlite3FindTable(db, zTableName, zDbName);
3595   if( !pTab || pTab->pSelect ){
3596     pTab = 0;
3597     goto error_out;
3598   }
3599 
3600   /* Find the column for which info is requested */
3601   if( zColumnName==0 ){
3602     /* Query for existance of table only */
3603   }else{
3604     for(iCol=0; iCol<pTab->nCol; iCol++){
3605       pCol = &pTab->aCol[iCol];
3606       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3607         break;
3608       }
3609     }
3610     if( iCol==pTab->nCol ){
3611       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3612         iCol = pTab->iPKey;
3613         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3614       }else{
3615         pTab = 0;
3616         goto error_out;
3617       }
3618     }
3619   }
3620 
3621   /* The following block stores the meta information that will be returned
3622   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3623   ** and autoinc. At this point there are two possibilities:
3624   **
3625   **     1. The specified column name was rowid", "oid" or "_rowid_"
3626   **        and there is no explicitly declared IPK column.
3627   **
3628   **     2. The table is not a view and the column name identified an
3629   **        explicitly declared column. Copy meta information from *pCol.
3630   */
3631   if( pCol ){
3632     zDataType = sqlite3ColumnType(pCol,0);
3633     zCollSeq = pCol->zColl;
3634     notnull = pCol->notNull!=0;
3635     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3636     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3637   }else{
3638     zDataType = "INTEGER";
3639     primarykey = 1;
3640   }
3641   if( !zCollSeq ){
3642     zCollSeq = sqlite3StrBINARY;
3643   }
3644 
3645 error_out:
3646   sqlite3BtreeLeaveAll(db);
3647 
3648   /* Whether the function call succeeded or failed, set the output parameters
3649   ** to whatever their local counterparts contain. If an error did occur,
3650   ** this has the effect of zeroing all output parameters.
3651   */
3652   if( pzDataType ) *pzDataType = zDataType;
3653   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3654   if( pNotNull ) *pNotNull = notnull;
3655   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3656   if( pAutoinc ) *pAutoinc = autoinc;
3657 
3658   if( SQLITE_OK==rc && !pTab ){
3659     sqlite3DbFree(db, zErrMsg);
3660     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3661         zColumnName);
3662     rc = SQLITE_ERROR;
3663   }
3664   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3665   sqlite3DbFree(db, zErrMsg);
3666   rc = sqlite3ApiExit(db, rc);
3667   sqlite3_mutex_leave(db->mutex);
3668   return rc;
3669 }
3670 
3671 /*
3672 ** Sleep for a little while.  Return the amount of time slept.
3673 */
3674 int sqlite3_sleep(int ms){
3675   sqlite3_vfs *pVfs;
3676   int rc;
3677   pVfs = sqlite3_vfs_find(0);
3678   if( pVfs==0 ) return 0;
3679 
3680   /* This function works in milliseconds, but the underlying OsSleep()
3681   ** API uses microseconds. Hence the 1000's.
3682   */
3683   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3684   return rc;
3685 }
3686 
3687 /*
3688 ** Enable or disable the extended result codes.
3689 */
3690 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3691 #ifdef SQLITE_ENABLE_API_ARMOR
3692   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3693 #endif
3694   sqlite3_mutex_enter(db->mutex);
3695   db->errMask = onoff ? 0xffffffff : 0xff;
3696   sqlite3_mutex_leave(db->mutex);
3697   return SQLITE_OK;
3698 }
3699 
3700 /*
3701 ** Invoke the xFileControl method on a particular database.
3702 */
3703 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3704   int rc = SQLITE_ERROR;
3705   Btree *pBtree;
3706 
3707 #ifdef SQLITE_ENABLE_API_ARMOR
3708   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3709 #endif
3710   sqlite3_mutex_enter(db->mutex);
3711   pBtree = sqlite3DbNameToBtree(db, zDbName);
3712   if( pBtree ){
3713     Pager *pPager;
3714     sqlite3_file *fd;
3715     sqlite3BtreeEnter(pBtree);
3716     pPager = sqlite3BtreePager(pBtree);
3717     assert( pPager!=0 );
3718     fd = sqlite3PagerFile(pPager);
3719     assert( fd!=0 );
3720     if( op==SQLITE_FCNTL_FILE_POINTER ){
3721       *(sqlite3_file**)pArg = fd;
3722       rc = SQLITE_OK;
3723     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3724       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3725       rc = SQLITE_OK;
3726     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3727       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3728       rc = SQLITE_OK;
3729     }else if( op==SQLITE_FCNTL_DATA_VERSION ){
3730       *(unsigned int*)pArg = sqlite3PagerDataVersion(pPager);
3731       rc = SQLITE_OK;
3732     }else{
3733       rc = sqlite3OsFileControl(fd, op, pArg);
3734     }
3735     sqlite3BtreeLeave(pBtree);
3736   }
3737   sqlite3_mutex_leave(db->mutex);
3738   return rc;
3739 }
3740 
3741 /*
3742 ** Interface to the testing logic.
3743 */
3744 int sqlite3_test_control(int op, ...){
3745   int rc = 0;
3746 #ifdef SQLITE_UNTESTABLE
3747   UNUSED_PARAMETER(op);
3748 #else
3749   va_list ap;
3750   va_start(ap, op);
3751   switch( op ){
3752 
3753     /*
3754     ** Save the current state of the PRNG.
3755     */
3756     case SQLITE_TESTCTRL_PRNG_SAVE: {
3757       sqlite3PrngSaveState();
3758       break;
3759     }
3760 
3761     /*
3762     ** Restore the state of the PRNG to the last state saved using
3763     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3764     ** this verb acts like PRNG_RESET.
3765     */
3766     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3767       sqlite3PrngRestoreState();
3768       break;
3769     }
3770 
3771     /*
3772     ** Reset the PRNG back to its uninitialized state.  The next call
3773     ** to sqlite3_randomness() will reseed the PRNG using a single call
3774     ** to the xRandomness method of the default VFS.
3775     */
3776     case SQLITE_TESTCTRL_PRNG_RESET: {
3777       sqlite3_randomness(0,0);
3778       break;
3779     }
3780 
3781     /*
3782     **  sqlite3_test_control(BITVEC_TEST, size, program)
3783     **
3784     ** Run a test against a Bitvec object of size.  The program argument
3785     ** is an array of integers that defines the test.  Return -1 on a
3786     ** memory allocation error, 0 on success, or non-zero for an error.
3787     ** See the sqlite3BitvecBuiltinTest() for additional information.
3788     */
3789     case SQLITE_TESTCTRL_BITVEC_TEST: {
3790       int sz = va_arg(ap, int);
3791       int *aProg = va_arg(ap, int*);
3792       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3793       break;
3794     }
3795 
3796     /*
3797     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3798     **
3799     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3800     ** if xCallback is not NULL.
3801     **
3802     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3803     ** is called immediately after installing the new callback and the return
3804     ** value from sqlite3FaultSim(0) becomes the return from
3805     ** sqlite3_test_control().
3806     */
3807     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3808       /* MSVC is picky about pulling func ptrs from va lists.
3809       ** http://support.microsoft.com/kb/47961
3810       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3811       */
3812       typedef int(*TESTCALLBACKFUNC_t)(int);
3813       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3814       rc = sqlite3FaultSim(0);
3815       break;
3816     }
3817 
3818     /*
3819     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3820     **
3821     ** Register hooks to call to indicate which malloc() failures
3822     ** are benign.
3823     */
3824     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3825       typedef void (*void_function)(void);
3826       void_function xBenignBegin;
3827       void_function xBenignEnd;
3828       xBenignBegin = va_arg(ap, void_function);
3829       xBenignEnd = va_arg(ap, void_function);
3830       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3831       break;
3832     }
3833 
3834     /*
3835     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3836     **
3837     ** Set the PENDING byte to the value in the argument, if X>0.
3838     ** Make no changes if X==0.  Return the value of the pending byte
3839     ** as it existing before this routine was called.
3840     **
3841     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3842     ** an incompatible database file format.  Changing the PENDING byte
3843     ** while any database connection is open results in undefined and
3844     ** deleterious behavior.
3845     */
3846     case SQLITE_TESTCTRL_PENDING_BYTE: {
3847       rc = PENDING_BYTE;
3848 #ifndef SQLITE_OMIT_WSD
3849       {
3850         unsigned int newVal = va_arg(ap, unsigned int);
3851         if( newVal ) sqlite3PendingByte = newVal;
3852       }
3853 #endif
3854       break;
3855     }
3856 
3857     /*
3858     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3859     **
3860     ** This action provides a run-time test to see whether or not
3861     ** assert() was enabled at compile-time.  If X is true and assert()
3862     ** is enabled, then the return value is true.  If X is true and
3863     ** assert() is disabled, then the return value is zero.  If X is
3864     ** false and assert() is enabled, then the assertion fires and the
3865     ** process aborts.  If X is false and assert() is disabled, then the
3866     ** return value is zero.
3867     */
3868     case SQLITE_TESTCTRL_ASSERT: {
3869       volatile int x = 0;
3870       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3871       rc = x;
3872       break;
3873     }
3874 
3875 
3876     /*
3877     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3878     **
3879     ** This action provides a run-time test to see how the ALWAYS and
3880     ** NEVER macros were defined at compile-time.
3881     **
3882     ** The return value is ALWAYS(X) if X is true, or 0 if X is false.
3883     **
3884     ** The recommended test is X==2.  If the return value is 2, that means
3885     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3886     ** default setting.  If the return value is 1, then ALWAYS() is either
3887     ** hard-coded to true or else it asserts if its argument is false.
3888     ** The first behavior (hard-coded to true) is the case if
3889     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3890     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3891     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3892     **
3893     ** The run-time test procedure might look something like this:
3894     **
3895     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3896     **      // ALWAYS() and NEVER() are no-op pass-through macros
3897     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3898     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3899     **    }else{
3900     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3901     **    }
3902     */
3903     case SQLITE_TESTCTRL_ALWAYS: {
3904       int x = va_arg(ap,int);
3905       rc = x ? ALWAYS(x) : 0;
3906       break;
3907     }
3908 
3909     /*
3910     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3911     **
3912     ** The integer returned reveals the byte-order of the computer on which
3913     ** SQLite is running:
3914     **
3915     **       1     big-endian,    determined at run-time
3916     **      10     little-endian, determined at run-time
3917     **  432101     big-endian,    determined at compile-time
3918     **  123410     little-endian, determined at compile-time
3919     */
3920     case SQLITE_TESTCTRL_BYTEORDER: {
3921       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3922       break;
3923     }
3924 
3925     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3926     **
3927     ** Set the nReserve size to N for the main database on the database
3928     ** connection db.
3929     */
3930     case SQLITE_TESTCTRL_RESERVE: {
3931       sqlite3 *db = va_arg(ap, sqlite3*);
3932       int x = va_arg(ap,int);
3933       sqlite3_mutex_enter(db->mutex);
3934       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3935       sqlite3_mutex_leave(db->mutex);
3936       break;
3937     }
3938 
3939     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3940     **
3941     ** Enable or disable various optimizations for testing purposes.  The
3942     ** argument N is a bitmask of optimizations to be disabled.  For normal
3943     ** operation N should be 0.  The idea is that a test program (like the
3944     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3945     ** with various optimizations disabled to verify that the same answer
3946     ** is obtained in every case.
3947     */
3948     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3949       sqlite3 *db = va_arg(ap, sqlite3*);
3950       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3951       break;
3952     }
3953 
3954     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3955     **
3956     ** If parameter onoff is non-zero, subsequent calls to localtime()
3957     ** and its variants fail. If onoff is zero, undo this setting.
3958     */
3959     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3960       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3961       break;
3962     }
3963 
3964     /*   sqlite3_test_control(SQLITE_TESTCTRL_INTERNAL_FUNCS, int onoff);
3965     **
3966     ** If parameter onoff is non-zero, internal-use-only SQL functions
3967     ** are visible to ordinary SQL.  This is useful for testing but is
3968     ** unsafe because invalid parameters to those internal-use-only functions
3969     ** can result in crashes or segfaults.
3970     */
3971     case SQLITE_TESTCTRL_INTERNAL_FUNCTIONS: {
3972       sqlite3GlobalConfig.bInternalFunctions = va_arg(ap, int);
3973       break;
3974     }
3975 
3976     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3977     **
3978     ** Set or clear a flag that indicates that the database file is always well-
3979     ** formed and never corrupt.  This flag is clear by default, indicating that
3980     ** database files might have arbitrary corruption.  Setting the flag during
3981     ** testing causes certain assert() statements in the code to be activated
3982     ** that demonstrat invariants on well-formed database files.
3983     */
3984     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3985       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3986       break;
3987     }
3988 
3989     /* Set the threshold at which OP_Once counters reset back to zero.
3990     ** By default this is 0x7ffffffe (over 2 billion), but that value is
3991     ** too big to test in a reasonable amount of time, so this control is
3992     ** provided to set a small and easily reachable reset value.
3993     */
3994     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
3995       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
3996       break;
3997     }
3998 
3999     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
4000     **
4001     ** Set the VDBE coverage callback function to xCallback with context
4002     ** pointer ptr.
4003     */
4004     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
4005 #ifdef SQLITE_VDBE_COVERAGE
4006       typedef void (*branch_callback)(void*,unsigned int,
4007                                       unsigned char,unsigned char);
4008       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
4009       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
4010 #endif
4011       break;
4012     }
4013 
4014     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
4015     case SQLITE_TESTCTRL_SORTER_MMAP: {
4016       sqlite3 *db = va_arg(ap, sqlite3*);
4017       db->nMaxSorterMmap = va_arg(ap, int);
4018       break;
4019     }
4020 
4021     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
4022     **
4023     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
4024     ** not.
4025     */
4026     case SQLITE_TESTCTRL_ISINIT: {
4027       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
4028       break;
4029     }
4030 
4031     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
4032     **
4033     ** This test control is used to create imposter tables.  "db" is a pointer
4034     ** to the database connection.  dbName is the database name (ex: "main" or
4035     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
4036     ** or off.  "tnum" is the root page of the b-tree to which the imposter
4037     ** table should connect.
4038     **
4039     ** Enable imposter mode only when the schema has already been parsed.  Then
4040     ** run a single CREATE TABLE statement to construct the imposter table in
4041     ** the parsed schema.  Then turn imposter mode back off again.
4042     **
4043     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
4044     ** the schema to be reparsed the next time it is needed.  This has the
4045     ** effect of erasing all imposter tables.
4046     */
4047     case SQLITE_TESTCTRL_IMPOSTER: {
4048       sqlite3 *db = va_arg(ap, sqlite3*);
4049       sqlite3_mutex_enter(db->mutex);
4050       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
4051       db->init.busy = db->init.imposterTable = va_arg(ap,int);
4052       db->init.newTnum = va_arg(ap,int);
4053       if( db->init.busy==0 && db->init.newTnum>0 ){
4054         sqlite3ResetAllSchemasOfConnection(db);
4055       }
4056       sqlite3_mutex_leave(db->mutex);
4057       break;
4058     }
4059 
4060 #if defined(YYCOVERAGE)
4061     /*  sqlite3_test_control(SQLITE_TESTCTRL_PARSER_COVERAGE, FILE *out)
4062     **
4063     ** This test control (only available when SQLite is compiled with
4064     ** -DYYCOVERAGE) writes a report onto "out" that shows all
4065     ** state/lookahead combinations in the parser state machine
4066     ** which are never exercised.  If any state is missed, make the
4067     ** return code SQLITE_ERROR.
4068     */
4069     case SQLITE_TESTCTRL_PARSER_COVERAGE: {
4070       FILE *out = va_arg(ap, FILE*);
4071       if( sqlite3ParserCoverage(out) ) rc = SQLITE_ERROR;
4072       break;
4073     }
4074 #endif /* defined(YYCOVERAGE) */
4075   }
4076   va_end(ap);
4077 #endif /* SQLITE_UNTESTABLE */
4078   return rc;
4079 }
4080 
4081 /*
4082 ** This is a utility routine, useful to VFS implementations, that checks
4083 ** to see if a database file was a URI that contained a specific query
4084 ** parameter, and if so obtains the value of the query parameter.
4085 **
4086 ** The zFilename argument is the filename pointer passed into the xOpen()
4087 ** method of a VFS implementation.  The zParam argument is the name of the
4088 ** query parameter we seek.  This routine returns the value of the zParam
4089 ** parameter if it exists.  If the parameter does not exist, this routine
4090 ** returns a NULL pointer.
4091 */
4092 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
4093   if( zFilename==0 || zParam==0 ) return 0;
4094   zFilename += sqlite3Strlen30(zFilename) + 1;
4095   while( zFilename[0] ){
4096     int x = strcmp(zFilename, zParam);
4097     zFilename += sqlite3Strlen30(zFilename) + 1;
4098     if( x==0 ) return zFilename;
4099     zFilename += sqlite3Strlen30(zFilename) + 1;
4100   }
4101   return 0;
4102 }
4103 
4104 /*
4105 ** Return a boolean value for a query parameter.
4106 */
4107 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
4108   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4109   bDflt = bDflt!=0;
4110   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
4111 }
4112 
4113 /*
4114 ** Return a 64-bit integer value for a query parameter.
4115 */
4116 sqlite3_int64 sqlite3_uri_int64(
4117   const char *zFilename,    /* Filename as passed to xOpen */
4118   const char *zParam,       /* URI parameter sought */
4119   sqlite3_int64 bDflt       /* return if parameter is missing */
4120 ){
4121   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4122   sqlite3_int64 v;
4123   if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
4124     bDflt = v;
4125   }
4126   return bDflt;
4127 }
4128 
4129 /*
4130 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
4131 */
4132 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
4133   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
4134   return iDb<0 ? 0 : db->aDb[iDb].pBt;
4135 }
4136 
4137 /*
4138 ** Return the filename of the database associated with a database
4139 ** connection.
4140 */
4141 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
4142   Btree *pBt;
4143 #ifdef SQLITE_ENABLE_API_ARMOR
4144   if( !sqlite3SafetyCheckOk(db) ){
4145     (void)SQLITE_MISUSE_BKPT;
4146     return 0;
4147   }
4148 #endif
4149   pBt = sqlite3DbNameToBtree(db, zDbName);
4150   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
4151 }
4152 
4153 /*
4154 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
4155 ** no such database exists.
4156 */
4157 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
4158   Btree *pBt;
4159 #ifdef SQLITE_ENABLE_API_ARMOR
4160   if( !sqlite3SafetyCheckOk(db) ){
4161     (void)SQLITE_MISUSE_BKPT;
4162     return -1;
4163   }
4164 #endif
4165   pBt = sqlite3DbNameToBtree(db, zDbName);
4166   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
4167 }
4168 
4169 #ifdef SQLITE_ENABLE_SNAPSHOT
4170 /*
4171 ** Obtain a snapshot handle for the snapshot of database zDb currently
4172 ** being read by handle db.
4173 */
4174 int sqlite3_snapshot_get(
4175   sqlite3 *db,
4176   const char *zDb,
4177   sqlite3_snapshot **ppSnapshot
4178 ){
4179   int rc = SQLITE_ERROR;
4180 #ifndef SQLITE_OMIT_WAL
4181 
4182 #ifdef SQLITE_ENABLE_API_ARMOR
4183   if( !sqlite3SafetyCheckOk(db) ){
4184     return SQLITE_MISUSE_BKPT;
4185   }
4186 #endif
4187   sqlite3_mutex_enter(db->mutex);
4188 
4189   if( db->autoCommit==0 ){
4190     int iDb = sqlite3FindDbName(db, zDb);
4191     if( iDb==0 || iDb>1 ){
4192       Btree *pBt = db->aDb[iDb].pBt;
4193       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4194         rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4195         if( rc==SQLITE_OK ){
4196           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4197         }
4198       }
4199     }
4200   }
4201 
4202   sqlite3_mutex_leave(db->mutex);
4203 #endif   /* SQLITE_OMIT_WAL */
4204   return rc;
4205 }
4206 
4207 /*
4208 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4209 */
4210 int sqlite3_snapshot_open(
4211   sqlite3 *db,
4212   const char *zDb,
4213   sqlite3_snapshot *pSnapshot
4214 ){
4215   int rc = SQLITE_ERROR;
4216 #ifndef SQLITE_OMIT_WAL
4217 
4218 #ifdef SQLITE_ENABLE_API_ARMOR
4219   if( !sqlite3SafetyCheckOk(db) ){
4220     return SQLITE_MISUSE_BKPT;
4221   }
4222 #endif
4223   sqlite3_mutex_enter(db->mutex);
4224   if( db->autoCommit==0 ){
4225     int iDb;
4226     iDb = sqlite3FindDbName(db, zDb);
4227     if( iDb==0 || iDb>1 ){
4228       Btree *pBt = db->aDb[iDb].pBt;
4229       if( sqlite3BtreeIsInTrans(pBt)==0 ){
4230         Pager *pPager = sqlite3BtreePager(pBt);
4231         int bUnlock = 0;
4232         if( sqlite3BtreeIsInReadTrans(pBt) ){
4233           if( db->nVdbeActive==0 ){
4234             rc = sqlite3PagerSnapshotCheck(pPager, pSnapshot);
4235             if( rc==SQLITE_OK ){
4236               bUnlock = 1;
4237               rc = sqlite3BtreeCommit(pBt);
4238             }
4239           }
4240         }else{
4241           rc = SQLITE_OK;
4242         }
4243         if( rc==SQLITE_OK ){
4244           rc = sqlite3PagerSnapshotOpen(pPager, pSnapshot);
4245         }
4246         if( rc==SQLITE_OK ){
4247           rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4248           sqlite3PagerSnapshotOpen(pPager, 0);
4249         }
4250         if( bUnlock ){
4251           sqlite3PagerSnapshotUnlock(pPager);
4252         }
4253       }
4254     }
4255   }
4256 
4257   sqlite3_mutex_leave(db->mutex);
4258 #endif   /* SQLITE_OMIT_WAL */
4259   return rc;
4260 }
4261 
4262 /*
4263 ** Recover as many snapshots as possible from the wal file associated with
4264 ** schema zDb of database db.
4265 */
4266 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4267   int rc = SQLITE_ERROR;
4268   int iDb;
4269 #ifndef SQLITE_OMIT_WAL
4270 
4271 #ifdef SQLITE_ENABLE_API_ARMOR
4272   if( !sqlite3SafetyCheckOk(db) ){
4273     return SQLITE_MISUSE_BKPT;
4274   }
4275 #endif
4276 
4277   sqlite3_mutex_enter(db->mutex);
4278   iDb = sqlite3FindDbName(db, zDb);
4279   if( iDb==0 || iDb>1 ){
4280     Btree *pBt = db->aDb[iDb].pBt;
4281     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4282       rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4283       if( rc==SQLITE_OK ){
4284         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4285         sqlite3BtreeCommit(pBt);
4286       }
4287     }
4288   }
4289   sqlite3_mutex_leave(db->mutex);
4290 #endif   /* SQLITE_OMIT_WAL */
4291   return rc;
4292 }
4293 
4294 /*
4295 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4296 */
4297 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4298   sqlite3_free(pSnapshot);
4299 }
4300 #endif /* SQLITE_ENABLE_SNAPSHOT */
4301 
4302 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4303 /*
4304 ** Given the name of a compile-time option, return true if that option
4305 ** was used and false if not.
4306 **
4307 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4308 ** is not required for a match.
4309 */
4310 int sqlite3_compileoption_used(const char *zOptName){
4311   int i, n;
4312   int nOpt;
4313   const char **azCompileOpt;
4314 
4315 #if SQLITE_ENABLE_API_ARMOR
4316   if( zOptName==0 ){
4317     (void)SQLITE_MISUSE_BKPT;
4318     return 0;
4319   }
4320 #endif
4321 
4322   azCompileOpt = sqlite3CompileOptions(&nOpt);
4323 
4324   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4325   n = sqlite3Strlen30(zOptName);
4326 
4327   /* Since nOpt is normally in single digits, a linear search is
4328   ** adequate. No need for a binary search. */
4329   for(i=0; i<nOpt; i++){
4330     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4331      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4332     ){
4333       return 1;
4334     }
4335   }
4336   return 0;
4337 }
4338 
4339 /*
4340 ** Return the N-th compile-time option string.  If N is out of range,
4341 ** return a NULL pointer.
4342 */
4343 const char *sqlite3_compileoption_get(int N){
4344   int nOpt;
4345   const char **azCompileOpt;
4346   azCompileOpt = sqlite3CompileOptions(&nOpt);
4347   if( N>=0 && N<nOpt ){
4348     return azCompileOpt[N];
4349   }
4350   return 0;
4351 }
4352 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4353