xref: /sqlite-3.40.0/src/main.c (revision 5976b2c8)
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 #ifdef SQLITE_ENABLE_DESERIALIZE
657     case SQLITE_CONFIG_MEMDB_MAXSIZE: {
658       sqlite3GlobalConfig.mxMemdbSize = va_arg(ap, sqlite3_int64);
659       break;
660     }
661 #endif /* SQLITE_ENABLE_DESERIALIZE */
662 
663     default: {
664       rc = SQLITE_ERROR;
665       break;
666     }
667   }
668   va_end(ap);
669   return rc;
670 }
671 
672 /*
673 ** Set up the lookaside buffers for a database connection.
674 ** Return SQLITE_OK on success.
675 ** If lookaside is already active, return SQLITE_BUSY.
676 **
677 ** The sz parameter is the number of bytes in each lookaside slot.
678 ** The cnt parameter is the number of slots.  If pStart is NULL the
679 ** space for the lookaside memory is obtained from sqlite3_malloc().
680 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
681 ** the lookaside memory.
682 */
683 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
684 #ifndef SQLITE_OMIT_LOOKASIDE
685   void *pStart;
686 
687   if( sqlite3LookasideUsed(db,0)>0 ){
688     return SQLITE_BUSY;
689   }
690   /* Free any existing lookaside buffer for this handle before
691   ** allocating a new one so we don't have to have space for
692   ** both at the same time.
693   */
694   if( db->lookaside.bMalloced ){
695     sqlite3_free(db->lookaside.pStart);
696   }
697   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
698   ** than a pointer to be useful.
699   */
700   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
701   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
702   if( cnt<0 ) cnt = 0;
703   if( sz==0 || cnt==0 ){
704     sz = 0;
705     pStart = 0;
706   }else if( pBuf==0 ){
707     sqlite3BeginBenignMalloc();
708     pStart = sqlite3Malloc( sz*(sqlite3_int64)cnt );  /* IMP: R-61949-35727 */
709     sqlite3EndBenignMalloc();
710     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
711   }else{
712     pStart = pBuf;
713   }
714   db->lookaside.pStart = pStart;
715   db->lookaside.pInit = 0;
716   db->lookaside.pFree = 0;
717   db->lookaside.sz = (u16)sz;
718   if( pStart ){
719     int i;
720     LookasideSlot *p;
721     assert( sz > (int)sizeof(LookasideSlot*) );
722     db->lookaside.nSlot = cnt;
723     p = (LookasideSlot*)pStart;
724     for(i=cnt-1; i>=0; i--){
725       p->pNext = db->lookaside.pInit;
726       db->lookaside.pInit = p;
727       p = (LookasideSlot*)&((u8*)p)[sz];
728     }
729     db->lookaside.pEnd = p;
730     db->lookaside.bDisable = 0;
731     db->lookaside.bMalloced = pBuf==0 ?1:0;
732   }else{
733     db->lookaside.pStart = db;
734     db->lookaside.pEnd = db;
735     db->lookaside.bDisable = 1;
736     db->lookaside.bMalloced = 0;
737     db->lookaside.nSlot = 0;
738   }
739 #endif /* SQLITE_OMIT_LOOKASIDE */
740   return SQLITE_OK;
741 }
742 
743 /*
744 ** Return the mutex associated with a database connection.
745 */
746 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
747 #ifdef SQLITE_ENABLE_API_ARMOR
748   if( !sqlite3SafetyCheckOk(db) ){
749     (void)SQLITE_MISUSE_BKPT;
750     return 0;
751   }
752 #endif
753   return db->mutex;
754 }
755 
756 /*
757 ** Free up as much memory as we can from the given database
758 ** connection.
759 */
760 int sqlite3_db_release_memory(sqlite3 *db){
761   int i;
762 
763 #ifdef SQLITE_ENABLE_API_ARMOR
764   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
765 #endif
766   sqlite3_mutex_enter(db->mutex);
767   sqlite3BtreeEnterAll(db);
768   for(i=0; i<db->nDb; i++){
769     Btree *pBt = db->aDb[i].pBt;
770     if( pBt ){
771       Pager *pPager = sqlite3BtreePager(pBt);
772       sqlite3PagerShrink(pPager);
773     }
774   }
775   sqlite3BtreeLeaveAll(db);
776   sqlite3_mutex_leave(db->mutex);
777   return SQLITE_OK;
778 }
779 
780 /*
781 ** Flush any dirty pages in the pager-cache for any attached database
782 ** to disk.
783 */
784 int sqlite3_db_cacheflush(sqlite3 *db){
785   int i;
786   int rc = SQLITE_OK;
787   int bSeenBusy = 0;
788 
789 #ifdef SQLITE_ENABLE_API_ARMOR
790   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
791 #endif
792   sqlite3_mutex_enter(db->mutex);
793   sqlite3BtreeEnterAll(db);
794   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
795     Btree *pBt = db->aDb[i].pBt;
796     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
797       Pager *pPager = sqlite3BtreePager(pBt);
798       rc = sqlite3PagerFlush(pPager);
799       if( rc==SQLITE_BUSY ){
800         bSeenBusy = 1;
801         rc = SQLITE_OK;
802       }
803     }
804   }
805   sqlite3BtreeLeaveAll(db);
806   sqlite3_mutex_leave(db->mutex);
807   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
808 }
809 
810 /*
811 ** Configuration settings for an individual database connection
812 */
813 int sqlite3_db_config(sqlite3 *db, int op, ...){
814   va_list ap;
815   int rc;
816   va_start(ap, op);
817   switch( op ){
818     case SQLITE_DBCONFIG_MAINDBNAME: {
819       /* IMP: R-06824-28531 */
820       /* IMP: R-36257-52125 */
821       db->aDb[0].zDbSName = va_arg(ap,char*);
822       rc = SQLITE_OK;
823       break;
824     }
825     case SQLITE_DBCONFIG_LOOKASIDE: {
826       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
827       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
828       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
829       rc = setupLookaside(db, pBuf, sz, cnt);
830       break;
831     }
832     default: {
833       static const struct {
834         int op;      /* The opcode */
835         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
836       } aFlagOp[] = {
837         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
838         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
839         { SQLITE_DBCONFIG_ENABLE_VIEW,           SQLITE_EnableView     },
840         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
841         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
842         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
843         { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
844         { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
845         { SQLITE_DBCONFIG_RESET_DATABASE,        SQLITE_ResetDatabase  },
846         { SQLITE_DBCONFIG_DEFENSIVE,             SQLITE_Defensive      },
847         { SQLITE_DBCONFIG_WRITABLE_SCHEMA,       SQLITE_WriteSchema|
848                                                  SQLITE_NoSchemaError  },
849         { SQLITE_DBCONFIG_LEGACY_ALTER_TABLE,    SQLITE_LegacyAlter    },
850         { SQLITE_DBCONFIG_DQS_DDL,               SQLITE_DqsDDL         },
851         { SQLITE_DBCONFIG_DQS_DML,               SQLITE_DqsDML         },
852       };
853       unsigned int i;
854       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
855       for(i=0; i<ArraySize(aFlagOp); i++){
856         if( aFlagOp[i].op==op ){
857           int onoff = va_arg(ap, int);
858           int *pRes = va_arg(ap, int*);
859           u64 oldFlags = db->flags;
860           if( onoff>0 ){
861             db->flags |= aFlagOp[i].mask;
862           }else if( onoff==0 ){
863             db->flags &= ~(u64)aFlagOp[i].mask;
864           }
865           if( oldFlags!=db->flags ){
866             sqlite3ExpirePreparedStatements(db, 0);
867           }
868           if( pRes ){
869             *pRes = (db->flags & aFlagOp[i].mask)!=0;
870           }
871           rc = SQLITE_OK;
872           break;
873         }
874       }
875       break;
876     }
877   }
878   va_end(ap);
879   return rc;
880 }
881 
882 /*
883 ** This is the default collating function named "BINARY" which is always
884 ** available.
885 */
886 static int binCollFunc(
887   void *NotUsed,
888   int nKey1, const void *pKey1,
889   int nKey2, const void *pKey2
890 ){
891   int rc, n;
892   UNUSED_PARAMETER(NotUsed);
893   n = nKey1<nKey2 ? nKey1 : nKey2;
894   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
895   ** strings byte by byte using the memcmp() function from the standard C
896   ** library. */
897   assert( pKey1 && pKey2 );
898   rc = memcmp(pKey1, pKey2, n);
899   if( rc==0 ){
900     rc = nKey1 - nKey2;
901   }
902   return rc;
903 }
904 
905 /*
906 ** This is the collating function named "RTRIM" which is always
907 ** available.  Ignore trailing spaces.
908 */
909 static int rtrimCollFunc(
910   void *pUser,
911   int nKey1, const void *pKey1,
912   int nKey2, const void *pKey2
913 ){
914   const u8 *pK1 = (const u8*)pKey1;
915   const u8 *pK2 = (const u8*)pKey2;
916   while( nKey1 && pK1[nKey1-1]==' ' ) nKey1--;
917   while( nKey2 && pK2[nKey2-1]==' ' ) nKey2--;
918   return binCollFunc(pUser, nKey1, pKey1, nKey2, pKey2);
919 }
920 
921 /*
922 ** Return true if CollSeq is the default built-in BINARY.
923 */
924 int sqlite3IsBinary(const CollSeq *p){
925   assert( p==0 || p->xCmp!=binCollFunc || strcmp(p->zName,"BINARY")==0 );
926   return p==0 || p->xCmp==binCollFunc;
927 }
928 
929 /*
930 ** Another built-in collating sequence: NOCASE.
931 **
932 ** This collating sequence is intended to be used for "case independent
933 ** comparison". SQLite's knowledge of upper and lower case equivalents
934 ** extends only to the 26 characters used in the English language.
935 **
936 ** At the moment there is only a UTF-8 implementation.
937 */
938 static int nocaseCollatingFunc(
939   void *NotUsed,
940   int nKey1, const void *pKey1,
941   int nKey2, const void *pKey2
942 ){
943   int r = sqlite3StrNICmp(
944       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
945   UNUSED_PARAMETER(NotUsed);
946   if( 0==r ){
947     r = nKey1-nKey2;
948   }
949   return r;
950 }
951 
952 /*
953 ** Return the ROWID of the most recent insert
954 */
955 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
956 #ifdef SQLITE_ENABLE_API_ARMOR
957   if( !sqlite3SafetyCheckOk(db) ){
958     (void)SQLITE_MISUSE_BKPT;
959     return 0;
960   }
961 #endif
962   return db->lastRowid;
963 }
964 
965 /*
966 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
967 */
968 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
969 #ifdef SQLITE_ENABLE_API_ARMOR
970   if( !sqlite3SafetyCheckOk(db) ){
971     (void)SQLITE_MISUSE_BKPT;
972     return;
973   }
974 #endif
975   sqlite3_mutex_enter(db->mutex);
976   db->lastRowid = iRowid;
977   sqlite3_mutex_leave(db->mutex);
978 }
979 
980 /*
981 ** Return the number of changes in the most recent call to sqlite3_exec().
982 */
983 int sqlite3_changes(sqlite3 *db){
984 #ifdef SQLITE_ENABLE_API_ARMOR
985   if( !sqlite3SafetyCheckOk(db) ){
986     (void)SQLITE_MISUSE_BKPT;
987     return 0;
988   }
989 #endif
990   return db->nChange;
991 }
992 
993 /*
994 ** Return the number of changes since the database handle was opened.
995 */
996 int sqlite3_total_changes(sqlite3 *db){
997 #ifdef SQLITE_ENABLE_API_ARMOR
998   if( !sqlite3SafetyCheckOk(db) ){
999     (void)SQLITE_MISUSE_BKPT;
1000     return 0;
1001   }
1002 #endif
1003   return db->nTotalChange;
1004 }
1005 
1006 /*
1007 ** Close all open savepoints. This function only manipulates fields of the
1008 ** database handle object, it does not close any savepoints that may be open
1009 ** at the b-tree/pager level.
1010 */
1011 void sqlite3CloseSavepoints(sqlite3 *db){
1012   while( db->pSavepoint ){
1013     Savepoint *pTmp = db->pSavepoint;
1014     db->pSavepoint = pTmp->pNext;
1015     sqlite3DbFree(db, pTmp);
1016   }
1017   db->nSavepoint = 0;
1018   db->nStatement = 0;
1019   db->isTransactionSavepoint = 0;
1020 }
1021 
1022 /*
1023 ** Invoke the destructor function associated with FuncDef p, if any. Except,
1024 ** if this is not the last copy of the function, do not invoke it. Multiple
1025 ** copies of a single function are created when create_function() is called
1026 ** with SQLITE_ANY as the encoding.
1027 */
1028 static void functionDestroy(sqlite3 *db, FuncDef *p){
1029   FuncDestructor *pDestructor = p->u.pDestructor;
1030   if( pDestructor ){
1031     pDestructor->nRef--;
1032     if( pDestructor->nRef==0 ){
1033       pDestructor->xDestroy(pDestructor->pUserData);
1034       sqlite3DbFree(db, pDestructor);
1035     }
1036   }
1037 }
1038 
1039 /*
1040 ** Disconnect all sqlite3_vtab objects that belong to database connection
1041 ** db. This is called when db is being closed.
1042 */
1043 static void disconnectAllVtab(sqlite3 *db){
1044 #ifndef SQLITE_OMIT_VIRTUALTABLE
1045   int i;
1046   HashElem *p;
1047   sqlite3BtreeEnterAll(db);
1048   for(i=0; i<db->nDb; i++){
1049     Schema *pSchema = db->aDb[i].pSchema;
1050     if( pSchema ){
1051       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1052         Table *pTab = (Table *)sqliteHashData(p);
1053         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1054       }
1055     }
1056   }
1057   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1058     Module *pMod = (Module *)sqliteHashData(p);
1059     if( pMod->pEpoTab ){
1060       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1061     }
1062   }
1063   sqlite3VtabUnlockList(db);
1064   sqlite3BtreeLeaveAll(db);
1065 #else
1066   UNUSED_PARAMETER(db);
1067 #endif
1068 }
1069 
1070 /*
1071 ** Return TRUE if database connection db has unfinalized prepared
1072 ** statements or unfinished sqlite3_backup objects.
1073 */
1074 static int connectionIsBusy(sqlite3 *db){
1075   int j;
1076   assert( sqlite3_mutex_held(db->mutex) );
1077   if( db->pVdbe ) return 1;
1078   for(j=0; j<db->nDb; j++){
1079     Btree *pBt = db->aDb[j].pBt;
1080     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1081   }
1082   return 0;
1083 }
1084 
1085 /*
1086 ** Close an existing SQLite database
1087 */
1088 static int sqlite3Close(sqlite3 *db, int forceZombie){
1089   if( !db ){
1090     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1091     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1092     return SQLITE_OK;
1093   }
1094   if( !sqlite3SafetyCheckSickOrOk(db) ){
1095     return SQLITE_MISUSE_BKPT;
1096   }
1097   sqlite3_mutex_enter(db->mutex);
1098   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1099     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1100   }
1101 
1102   /* Force xDisconnect calls on all virtual tables */
1103   disconnectAllVtab(db);
1104 
1105   /* If a transaction is open, the disconnectAllVtab() call above
1106   ** will not have called the xDisconnect() method on any virtual
1107   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1108   ** call will do so. We need to do this before the check for active
1109   ** SQL statements below, as the v-table implementation may be storing
1110   ** some prepared statements internally.
1111   */
1112   sqlite3VtabRollback(db);
1113 
1114   /* Legacy behavior (sqlite3_close() behavior) is to return
1115   ** SQLITE_BUSY if the connection can not be closed immediately.
1116   */
1117   if( !forceZombie && connectionIsBusy(db) ){
1118     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1119        "statements or unfinished backups");
1120     sqlite3_mutex_leave(db->mutex);
1121     return SQLITE_BUSY;
1122   }
1123 
1124 #ifdef SQLITE_ENABLE_SQLLOG
1125   if( sqlite3GlobalConfig.xSqllog ){
1126     /* Closing the handle. Fourth parameter is passed the value 2. */
1127     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1128   }
1129 #endif
1130 
1131   /* Convert the connection into a zombie and then close it.
1132   */
1133   db->magic = SQLITE_MAGIC_ZOMBIE;
1134   sqlite3LeaveMutexAndCloseZombie(db);
1135   return SQLITE_OK;
1136 }
1137 
1138 /*
1139 ** Two variations on the public interface for closing a database
1140 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1141 ** leaves the connection option if there are unfinalized prepared
1142 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1143 ** version forces the connection to become a zombie if there are
1144 ** unclosed resources, and arranges for deallocation when the last
1145 ** prepare statement or sqlite3_backup closes.
1146 */
1147 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1148 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1149 
1150 
1151 /*
1152 ** Close the mutex on database connection db.
1153 **
1154 ** Furthermore, if database connection db is a zombie (meaning that there
1155 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1156 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1157 ** finished, then free all resources.
1158 */
1159 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1160   HashElem *i;                    /* Hash table iterator */
1161   int j;
1162 
1163   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1164   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1165   ** then just leave the mutex and return.
1166   */
1167   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1168     sqlite3_mutex_leave(db->mutex);
1169     return;
1170   }
1171 
1172   /* If we reach this point, it means that the database connection has
1173   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1174   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1175   ** go ahead and free all resources.
1176   */
1177 
1178   /* If a transaction is open, roll it back. This also ensures that if
1179   ** any database schemas have been modified by an uncommitted transaction
1180   ** they are reset. And that the required b-tree mutex is held to make
1181   ** the pager rollback and schema reset an atomic operation. */
1182   sqlite3RollbackAll(db, SQLITE_OK);
1183 
1184   /* Free any outstanding Savepoint structures. */
1185   sqlite3CloseSavepoints(db);
1186 
1187   /* Close all database connections */
1188   for(j=0; j<db->nDb; j++){
1189     struct Db *pDb = &db->aDb[j];
1190     if( pDb->pBt ){
1191       sqlite3BtreeClose(pDb->pBt);
1192       pDb->pBt = 0;
1193       if( j!=1 ){
1194         pDb->pSchema = 0;
1195       }
1196     }
1197   }
1198   /* Clear the TEMP schema separately and last */
1199   if( db->aDb[1].pSchema ){
1200     sqlite3SchemaClear(db->aDb[1].pSchema);
1201   }
1202   sqlite3VtabUnlockList(db);
1203 
1204   /* Free up the array of auxiliary databases */
1205   sqlite3CollapseDatabaseArray(db);
1206   assert( db->nDb<=2 );
1207   assert( db->aDb==db->aDbStatic );
1208 
1209   /* Tell the code in notify.c that the connection no longer holds any
1210   ** locks and does not require any further unlock-notify callbacks.
1211   */
1212   sqlite3ConnectionClosed(db);
1213 
1214   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1215     FuncDef *pNext, *p;
1216     p = sqliteHashData(i);
1217     do{
1218       functionDestroy(db, p);
1219       pNext = p->pNext;
1220       sqlite3DbFree(db, p);
1221       p = pNext;
1222     }while( p );
1223   }
1224   sqlite3HashClear(&db->aFunc);
1225   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1226     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1227     /* Invoke any destructors registered for collation sequence user data. */
1228     for(j=0; j<3; j++){
1229       if( pColl[j].xDel ){
1230         pColl[j].xDel(pColl[j].pUser);
1231       }
1232     }
1233     sqlite3DbFree(db, pColl);
1234   }
1235   sqlite3HashClear(&db->aCollSeq);
1236 #ifndef SQLITE_OMIT_VIRTUALTABLE
1237   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1238     Module *pMod = (Module *)sqliteHashData(i);
1239     sqlite3VtabEponymousTableClear(db, pMod);
1240     sqlite3VtabModuleUnref(db, pMod);
1241   }
1242   sqlite3HashClear(&db->aModule);
1243 #endif
1244 
1245   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1246   sqlite3ValueFree(db->pErr);
1247   sqlite3CloseExtensions(db);
1248 #if SQLITE_USER_AUTHENTICATION
1249   sqlite3_free(db->auth.zAuthUser);
1250   sqlite3_free(db->auth.zAuthPW);
1251 #endif
1252 
1253   db->magic = SQLITE_MAGIC_ERROR;
1254 
1255   /* The temp-database schema is allocated differently from the other schema
1256   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1257   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1258   ** the same sqliteMalloc() as the one that allocates the database
1259   ** structure?
1260   */
1261   sqlite3DbFree(db, db->aDb[1].pSchema);
1262   sqlite3_mutex_leave(db->mutex);
1263   db->magic = SQLITE_MAGIC_CLOSED;
1264   sqlite3_mutex_free(db->mutex);
1265   assert( sqlite3LookasideUsed(db,0)==0 );
1266   if( db->lookaside.bMalloced ){
1267     sqlite3_free(db->lookaside.pStart);
1268   }
1269   sqlite3_free(db);
1270 }
1271 
1272 /*
1273 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1274 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1275 ** breaker") and made to return tripCode if there are any further
1276 ** attempts to use that cursor.  Read cursors remain open and valid
1277 ** but are "saved" in case the table pages are moved around.
1278 */
1279 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1280   int i;
1281   int inTrans = 0;
1282   int schemaChange;
1283   assert( sqlite3_mutex_held(db->mutex) );
1284   sqlite3BeginBenignMalloc();
1285 
1286   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1287   ** This is important in case the transaction being rolled back has
1288   ** modified the database schema. If the b-tree mutexes are not taken
1289   ** here, then another shared-cache connection might sneak in between
1290   ** the database rollback and schema reset, which can cause false
1291   ** corruption reports in some cases.  */
1292   sqlite3BtreeEnterAll(db);
1293   schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
1294 
1295   for(i=0; i<db->nDb; i++){
1296     Btree *p = db->aDb[i].pBt;
1297     if( p ){
1298       if( sqlite3BtreeIsInTrans(p) ){
1299         inTrans = 1;
1300       }
1301       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1302     }
1303   }
1304   sqlite3VtabRollback(db);
1305   sqlite3EndBenignMalloc();
1306 
1307   if( schemaChange ){
1308     sqlite3ExpirePreparedStatements(db, 0);
1309     sqlite3ResetAllSchemasOfConnection(db);
1310   }
1311   sqlite3BtreeLeaveAll(db);
1312 
1313   /* Any deferred constraint violations have now been resolved. */
1314   db->nDeferredCons = 0;
1315   db->nDeferredImmCons = 0;
1316   db->flags &= ~(u64)SQLITE_DeferFKs;
1317 
1318   /* If one has been configured, invoke the rollback-hook callback */
1319   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1320     db->xRollbackCallback(db->pRollbackArg);
1321   }
1322 }
1323 
1324 /*
1325 ** Return a static string containing the name corresponding to the error code
1326 ** specified in the argument.
1327 */
1328 #if defined(SQLITE_NEED_ERR_NAME)
1329 const char *sqlite3ErrName(int rc){
1330   const char *zName = 0;
1331   int i, origRc = rc;
1332   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1333     switch( rc ){
1334       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1335       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1336       case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;
1337       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1338       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1339       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1340       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1341       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1342       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1343       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1344       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1345       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1346       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1347       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1348       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1349       case SQLITE_READONLY_CANTINIT:  zName = "SQLITE_READONLY_CANTINIT"; break;
1350       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1351       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1352       case SQLITE_READONLY_DIRECTORY: zName = "SQLITE_READONLY_DIRECTORY";break;
1353       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1354       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1355       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1356       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1357       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1358       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1359       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1360       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1361       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1362       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1363       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1364       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1365       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1366       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1367       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1368                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1369       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1370       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1371       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1372       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1373       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1374       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1375       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1376       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1377       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1378       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1379       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1380       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1381       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1382       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1383       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1384       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1385       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1386       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1387       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1388       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1389       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1390       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1391       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1392       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1393       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1394       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1395       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1396       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1397       case SQLITE_CONSTRAINT_FOREIGNKEY:
1398                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1399       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1400       case SQLITE_CONSTRAINT_PRIMARYKEY:
1401                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1402       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1403       case SQLITE_CONSTRAINT_COMMITHOOK:
1404                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1405       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1406       case SQLITE_CONSTRAINT_FUNCTION:
1407                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1408       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1409       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1410       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1411       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1412       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1413       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1414       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1415       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1416       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1417       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1418       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1419       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1420                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1421       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1422       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1423       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1424     }
1425   }
1426   if( zName==0 ){
1427     static char zBuf[50];
1428     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1429     zName = zBuf;
1430   }
1431   return zName;
1432 }
1433 #endif
1434 
1435 /*
1436 ** Return a static string that describes the kind of error specified in the
1437 ** argument.
1438 */
1439 const char *sqlite3ErrStr(int rc){
1440   static const char* const aMsg[] = {
1441     /* SQLITE_OK          */ "not an error",
1442     /* SQLITE_ERROR       */ "SQL logic error",
1443     /* SQLITE_INTERNAL    */ 0,
1444     /* SQLITE_PERM        */ "access permission denied",
1445     /* SQLITE_ABORT       */ "query aborted",
1446     /* SQLITE_BUSY        */ "database is locked",
1447     /* SQLITE_LOCKED      */ "database table is locked",
1448     /* SQLITE_NOMEM       */ "out of memory",
1449     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1450     /* SQLITE_INTERRUPT   */ "interrupted",
1451     /* SQLITE_IOERR       */ "disk I/O error",
1452     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1453     /* SQLITE_NOTFOUND    */ "unknown operation",
1454     /* SQLITE_FULL        */ "database or disk is full",
1455     /* SQLITE_CANTOPEN    */ "unable to open database file",
1456     /* SQLITE_PROTOCOL    */ "locking protocol",
1457     /* SQLITE_EMPTY       */ 0,
1458     /* SQLITE_SCHEMA      */ "database schema has changed",
1459     /* SQLITE_TOOBIG      */ "string or blob too big",
1460     /* SQLITE_CONSTRAINT  */ "constraint failed",
1461     /* SQLITE_MISMATCH    */ "datatype mismatch",
1462     /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
1463 #ifdef SQLITE_DISABLE_LFS
1464     /* SQLITE_NOLFS       */ "large file support is disabled",
1465 #else
1466     /* SQLITE_NOLFS       */ 0,
1467 #endif
1468     /* SQLITE_AUTH        */ "authorization denied",
1469     /* SQLITE_FORMAT      */ 0,
1470     /* SQLITE_RANGE       */ "column index out of range",
1471     /* SQLITE_NOTADB      */ "file is not a database",
1472     /* SQLITE_NOTICE      */ "notification message",
1473     /* SQLITE_WARNING     */ "warning message",
1474   };
1475   const char *zErr = "unknown error";
1476   switch( rc ){
1477     case SQLITE_ABORT_ROLLBACK: {
1478       zErr = "abort due to ROLLBACK";
1479       break;
1480     }
1481     case SQLITE_ROW: {
1482       zErr = "another row available";
1483       break;
1484     }
1485     case SQLITE_DONE: {
1486       zErr = "no more rows available";
1487       break;
1488     }
1489     default: {
1490       rc &= 0xff;
1491       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1492         zErr = aMsg[rc];
1493       }
1494       break;
1495     }
1496   }
1497   return zErr;
1498 }
1499 
1500 /*
1501 ** This routine implements a busy callback that sleeps and tries
1502 ** again until a timeout value is reached.  The timeout value is
1503 ** an integer number of milliseconds passed in as the first
1504 ** argument.
1505 **
1506 ** Return non-zero to retry the lock.  Return zero to stop trying
1507 ** and cause SQLite to return SQLITE_BUSY.
1508 */
1509 static int sqliteDefaultBusyCallback(
1510   void *ptr,               /* Database connection */
1511   int count,               /* Number of times table has been busy */
1512   sqlite3_file *pFile      /* The file on which the lock occurred */
1513 ){
1514 #if SQLITE_OS_WIN || HAVE_USLEEP
1515   /* This case is for systems that have support for sleeping for fractions of
1516   ** a second.  Examples:  All windows systems, unix systems with usleep() */
1517   static const u8 delays[] =
1518      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1519   static const u8 totals[] =
1520      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1521 # define NDELAY ArraySize(delays)
1522   sqlite3 *db = (sqlite3 *)ptr;
1523   int tmout = db->busyTimeout;
1524   int delay, prior;
1525 
1526 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
1527   if( sqlite3OsFileControl(pFile,SQLITE_FCNTL_LOCK_TIMEOUT,&tmout)==SQLITE_OK ){
1528     if( count ){
1529       tmout = 0;
1530       sqlite3OsFileControl(pFile, SQLITE_FCNTL_LOCK_TIMEOUT, &tmout);
1531       return 0;
1532     }else{
1533       return 1;
1534     }
1535   }
1536 #else
1537   UNUSED_PARAMETER(pFile);
1538 #endif
1539   assert( count>=0 );
1540   if( count < NDELAY ){
1541     delay = delays[count];
1542     prior = totals[count];
1543   }else{
1544     delay = delays[NDELAY-1];
1545     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1546   }
1547   if( prior + delay > tmout ){
1548     delay = tmout - prior;
1549     if( delay<=0 ) return 0;
1550   }
1551   sqlite3OsSleep(db->pVfs, delay*1000);
1552   return 1;
1553 #else
1554   /* This case for unix systems that lack usleep() support.  Sleeping
1555   ** must be done in increments of whole seconds */
1556   sqlite3 *db = (sqlite3 *)ptr;
1557   int tmout = ((sqlite3 *)ptr)->busyTimeout;
1558   UNUSED_PARAMETER(pFile);
1559   if( (count+1)*1000 > tmout ){
1560     return 0;
1561   }
1562   sqlite3OsSleep(db->pVfs, 1000000);
1563   return 1;
1564 #endif
1565 }
1566 
1567 /*
1568 ** Invoke the given busy handler.
1569 **
1570 ** This routine is called when an operation failed to acquire a
1571 ** lock on VFS file pFile.
1572 **
1573 ** If this routine returns non-zero, the lock is retried.  If it
1574 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1575 */
1576 int sqlite3InvokeBusyHandler(BusyHandler *p, sqlite3_file *pFile){
1577   int rc;
1578   if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
1579   if( p->bExtraFileArg ){
1580     /* Add an extra parameter with the pFile pointer to the end of the
1581     ** callback argument list */
1582     int (*xTra)(void*,int,sqlite3_file*);
1583     xTra = (int(*)(void*,int,sqlite3_file*))p->xBusyHandler;
1584     rc = xTra(p->pBusyArg, p->nBusy, pFile);
1585   }else{
1586     /* Legacy style busy handler callback */
1587     rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
1588   }
1589   if( rc==0 ){
1590     p->nBusy = -1;
1591   }else{
1592     p->nBusy++;
1593   }
1594   return rc;
1595 }
1596 
1597 /*
1598 ** This routine sets the busy callback for an Sqlite database to the
1599 ** given callback function with the given argument.
1600 */
1601 int sqlite3_busy_handler(
1602   sqlite3 *db,
1603   int (*xBusy)(void*,int),
1604   void *pArg
1605 ){
1606 #ifdef SQLITE_ENABLE_API_ARMOR
1607   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1608 #endif
1609   sqlite3_mutex_enter(db->mutex);
1610   db->busyHandler.xBusyHandler = xBusy;
1611   db->busyHandler.pBusyArg = pArg;
1612   db->busyHandler.nBusy = 0;
1613   db->busyHandler.bExtraFileArg = 0;
1614   db->busyTimeout = 0;
1615   sqlite3_mutex_leave(db->mutex);
1616   return SQLITE_OK;
1617 }
1618 
1619 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1620 /*
1621 ** This routine sets the progress callback for an Sqlite database to the
1622 ** given callback function with the given argument. The progress callback will
1623 ** be invoked every nOps opcodes.
1624 */
1625 void sqlite3_progress_handler(
1626   sqlite3 *db,
1627   int nOps,
1628   int (*xProgress)(void*),
1629   void *pArg
1630 ){
1631 #ifdef SQLITE_ENABLE_API_ARMOR
1632   if( !sqlite3SafetyCheckOk(db) ){
1633     (void)SQLITE_MISUSE_BKPT;
1634     return;
1635   }
1636 #endif
1637   sqlite3_mutex_enter(db->mutex);
1638   if( nOps>0 ){
1639     db->xProgress = xProgress;
1640     db->nProgressOps = (unsigned)nOps;
1641     db->pProgressArg = pArg;
1642   }else{
1643     db->xProgress = 0;
1644     db->nProgressOps = 0;
1645     db->pProgressArg = 0;
1646   }
1647   sqlite3_mutex_leave(db->mutex);
1648 }
1649 #endif
1650 
1651 
1652 /*
1653 ** This routine installs a default busy handler that waits for the
1654 ** specified number of milliseconds before returning 0.
1655 */
1656 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1657 #ifdef SQLITE_ENABLE_API_ARMOR
1658   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1659 #endif
1660   if( ms>0 ){
1661     sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
1662                              (void*)db);
1663     db->busyTimeout = ms;
1664     db->busyHandler.bExtraFileArg = 1;
1665   }else{
1666     sqlite3_busy_handler(db, 0, 0);
1667   }
1668   return SQLITE_OK;
1669 }
1670 
1671 /*
1672 ** Cause any pending operation to stop at its earliest opportunity.
1673 */
1674 void sqlite3_interrupt(sqlite3 *db){
1675 #ifdef SQLITE_ENABLE_API_ARMOR
1676   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1677     (void)SQLITE_MISUSE_BKPT;
1678     return;
1679   }
1680 #endif
1681   db->u1.isInterrupted = 1;
1682 }
1683 
1684 
1685 /*
1686 ** This function is exactly the same as sqlite3_create_function(), except
1687 ** that it is designed to be called by internal code. The difference is
1688 ** that if a malloc() fails in sqlite3_create_function(), an error code
1689 ** is returned and the mallocFailed flag cleared.
1690 */
1691 int sqlite3CreateFunc(
1692   sqlite3 *db,
1693   const char *zFunctionName,
1694   int nArg,
1695   int enc,
1696   void *pUserData,
1697   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1698   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1699   void (*xFinal)(sqlite3_context*),
1700   void (*xValue)(sqlite3_context*),
1701   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1702   FuncDestructor *pDestructor
1703 ){
1704   FuncDef *p;
1705   int nName;
1706   int extraFlags;
1707 
1708   assert( sqlite3_mutex_held(db->mutex) );
1709   assert( xValue==0 || xSFunc==0 );
1710   if( zFunctionName==0                /* Must have a valid name */
1711    || (xSFunc!=0 && xFinal!=0)        /* Not both xSFunc and xFinal */
1712    || ((xFinal==0)!=(xStep==0))       /* Both or neither of xFinal and xStep */
1713    || ((xValue==0)!=(xInverse==0))    /* Both or neither of xValue, xInverse */
1714    || (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG)
1715    || (255<(nName = sqlite3Strlen30( zFunctionName)))
1716   ){
1717     return SQLITE_MISUSE_BKPT;
1718   }
1719 
1720   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1721   assert( SQLITE_FUNC_DIRECT==SQLITE_DIRECTONLY );
1722   extraFlags = enc &  (SQLITE_DETERMINISTIC|SQLITE_DIRECTONLY);
1723   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1724 
1725 #ifndef SQLITE_OMIT_UTF16
1726   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1727   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1728   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1729   **
1730   ** If SQLITE_ANY is specified, add three versions of the function
1731   ** to the hash table.
1732   */
1733   if( enc==SQLITE_UTF16 ){
1734     enc = SQLITE_UTF16NATIVE;
1735   }else if( enc==SQLITE_ANY ){
1736     int rc;
1737     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1738          pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1739     if( rc==SQLITE_OK ){
1740       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1741           pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1742     }
1743     if( rc!=SQLITE_OK ){
1744       return rc;
1745     }
1746     enc = SQLITE_UTF16BE;
1747   }
1748 #else
1749   enc = SQLITE_UTF8;
1750 #endif
1751 
1752   /* Check if an existing function is being overridden or deleted. If so,
1753   ** and there are active VMs, then return SQLITE_BUSY. If a function
1754   ** is being overridden/deleted but there are no active VMs, allow the
1755   ** operation to continue but invalidate all precompiled statements.
1756   */
1757   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1758   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==(u32)enc && p->nArg==nArg ){
1759     if( db->nVdbeActive ){
1760       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1761         "unable to delete/modify user-function due to active statements");
1762       assert( !db->mallocFailed );
1763       return SQLITE_BUSY;
1764     }else{
1765       sqlite3ExpirePreparedStatements(db, 0);
1766     }
1767   }
1768 
1769   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1770   assert(p || db->mallocFailed);
1771   if( !p ){
1772     return SQLITE_NOMEM_BKPT;
1773   }
1774 
1775   /* If an older version of the function with a configured destructor is
1776   ** being replaced invoke the destructor function here. */
1777   functionDestroy(db, p);
1778 
1779   if( pDestructor ){
1780     pDestructor->nRef++;
1781   }
1782   p->u.pDestructor = pDestructor;
1783   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1784   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1785   testcase( p->funcFlags & SQLITE_DIRECTONLY );
1786   p->xSFunc = xSFunc ? xSFunc : xStep;
1787   p->xFinalize = xFinal;
1788   p->xValue = xValue;
1789   p->xInverse = xInverse;
1790   p->pUserData = pUserData;
1791   p->nArg = (u16)nArg;
1792   return SQLITE_OK;
1793 }
1794 
1795 /*
1796 ** Worker function used by utf-8 APIs that create new functions:
1797 **
1798 **    sqlite3_create_function()
1799 **    sqlite3_create_function_v2()
1800 **    sqlite3_create_window_function()
1801 */
1802 static int createFunctionApi(
1803   sqlite3 *db,
1804   const char *zFunc,
1805   int nArg,
1806   int enc,
1807   void *p,
1808   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1809   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1810   void (*xFinal)(sqlite3_context*),
1811   void (*xValue)(sqlite3_context*),
1812   void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
1813   void(*xDestroy)(void*)
1814 ){
1815   int rc = SQLITE_ERROR;
1816   FuncDestructor *pArg = 0;
1817 
1818 #ifdef SQLITE_ENABLE_API_ARMOR
1819   if( !sqlite3SafetyCheckOk(db) ){
1820     return SQLITE_MISUSE_BKPT;
1821   }
1822 #endif
1823   sqlite3_mutex_enter(db->mutex);
1824   if( xDestroy ){
1825     pArg = (FuncDestructor *)sqlite3Malloc(sizeof(FuncDestructor));
1826     if( !pArg ){
1827       sqlite3OomFault(db);
1828       xDestroy(p);
1829       goto out;
1830     }
1831     pArg->nRef = 0;
1832     pArg->xDestroy = xDestroy;
1833     pArg->pUserData = p;
1834   }
1835   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p,
1836       xSFunc, xStep, xFinal, xValue, xInverse, pArg
1837   );
1838   if( pArg && pArg->nRef==0 ){
1839     assert( rc!=SQLITE_OK );
1840     xDestroy(p);
1841     sqlite3_free(pArg);
1842   }
1843 
1844  out:
1845   rc = sqlite3ApiExit(db, rc);
1846   sqlite3_mutex_leave(db->mutex);
1847   return rc;
1848 }
1849 
1850 /*
1851 ** Create new user functions.
1852 */
1853 int sqlite3_create_function(
1854   sqlite3 *db,
1855   const char *zFunc,
1856   int nArg,
1857   int enc,
1858   void *p,
1859   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1860   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1861   void (*xFinal)(sqlite3_context*)
1862 ){
1863   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1864                                     xFinal, 0, 0, 0);
1865 }
1866 int sqlite3_create_function_v2(
1867   sqlite3 *db,
1868   const char *zFunc,
1869   int nArg,
1870   int enc,
1871   void *p,
1872   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1873   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1874   void (*xFinal)(sqlite3_context*),
1875   void (*xDestroy)(void *)
1876 ){
1877   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1878                                     xFinal, 0, 0, xDestroy);
1879 }
1880 int sqlite3_create_window_function(
1881   sqlite3 *db,
1882   const char *zFunc,
1883   int nArg,
1884   int enc,
1885   void *p,
1886   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1887   void (*xFinal)(sqlite3_context*),
1888   void (*xValue)(sqlite3_context*),
1889   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1890   void (*xDestroy)(void *)
1891 ){
1892   return createFunctionApi(db, zFunc, nArg, enc, p, 0, xStep,
1893                                     xFinal, xValue, xInverse, xDestroy);
1894 }
1895 
1896 #ifndef SQLITE_OMIT_UTF16
1897 int sqlite3_create_function16(
1898   sqlite3 *db,
1899   const void *zFunctionName,
1900   int nArg,
1901   int eTextRep,
1902   void *p,
1903   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1904   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1905   void (*xFinal)(sqlite3_context*)
1906 ){
1907   int rc;
1908   char *zFunc8;
1909 
1910 #ifdef SQLITE_ENABLE_API_ARMOR
1911   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1912 #endif
1913   sqlite3_mutex_enter(db->mutex);
1914   assert( !db->mallocFailed );
1915   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1916   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0,0,0);
1917   sqlite3DbFree(db, zFunc8);
1918   rc = sqlite3ApiExit(db, rc);
1919   sqlite3_mutex_leave(db->mutex);
1920   return rc;
1921 }
1922 #endif
1923 
1924 
1925 /*
1926 ** The following is the implementation of an SQL function that always
1927 ** fails with an error message stating that the function is used in the
1928 ** wrong context.  The sqlite3_overload_function() API might construct
1929 ** SQL function that use this routine so that the functions will exist
1930 ** for name resolution but are actually overloaded by the xFindFunction
1931 ** method of virtual tables.
1932 */
1933 static void sqlite3InvalidFunction(
1934   sqlite3_context *context,  /* The function calling context */
1935   int NotUsed,               /* Number of arguments to the function */
1936   sqlite3_value **NotUsed2   /* Value of each argument */
1937 ){
1938   const char *zName = (const char*)sqlite3_user_data(context);
1939   char *zErr;
1940   UNUSED_PARAMETER2(NotUsed, NotUsed2);
1941   zErr = sqlite3_mprintf(
1942       "unable to use function %s in the requested context", zName);
1943   sqlite3_result_error(context, zErr, -1);
1944   sqlite3_free(zErr);
1945 }
1946 
1947 /*
1948 ** Declare that a function has been overloaded by a virtual table.
1949 **
1950 ** If the function already exists as a regular global function, then
1951 ** this routine is a no-op.  If the function does not exist, then create
1952 ** a new one that always throws a run-time error.
1953 **
1954 ** When virtual tables intend to provide an overloaded function, they
1955 ** should call this routine to make sure the global function exists.
1956 ** A global function must exist in order for name resolution to work
1957 ** properly.
1958 */
1959 int sqlite3_overload_function(
1960   sqlite3 *db,
1961   const char *zName,
1962   int nArg
1963 ){
1964   int rc;
1965   char *zCopy;
1966 
1967 #ifdef SQLITE_ENABLE_API_ARMOR
1968   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1969     return SQLITE_MISUSE_BKPT;
1970   }
1971 #endif
1972   sqlite3_mutex_enter(db->mutex);
1973   rc = sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)!=0;
1974   sqlite3_mutex_leave(db->mutex);
1975   if( rc ) return SQLITE_OK;
1976   zCopy = sqlite3_mprintf(zName);
1977   if( zCopy==0 ) return SQLITE_NOMEM;
1978   return sqlite3_create_function_v2(db, zName, nArg, SQLITE_UTF8,
1979                            zCopy, sqlite3InvalidFunction, 0, 0, sqlite3_free);
1980 }
1981 
1982 #ifndef SQLITE_OMIT_TRACE
1983 /*
1984 ** Register a trace function.  The pArg from the previously registered trace
1985 ** is returned.
1986 **
1987 ** A NULL trace function means that no tracing is executes.  A non-NULL
1988 ** trace is a pointer to a function that is invoked at the start of each
1989 ** SQL statement.
1990 */
1991 #ifndef SQLITE_OMIT_DEPRECATED
1992 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1993   void *pOld;
1994 
1995 #ifdef SQLITE_ENABLE_API_ARMOR
1996   if( !sqlite3SafetyCheckOk(db) ){
1997     (void)SQLITE_MISUSE_BKPT;
1998     return 0;
1999   }
2000 #endif
2001   sqlite3_mutex_enter(db->mutex);
2002   pOld = db->pTraceArg;
2003   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
2004   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
2005   db->pTraceArg = pArg;
2006   sqlite3_mutex_leave(db->mutex);
2007   return pOld;
2008 }
2009 #endif /* SQLITE_OMIT_DEPRECATED */
2010 
2011 /* Register a trace callback using the version-2 interface.
2012 */
2013 int sqlite3_trace_v2(
2014   sqlite3 *db,                               /* Trace this connection */
2015   unsigned mTrace,                           /* Mask of events to be traced */
2016   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
2017   void *pArg                                 /* Context */
2018 ){
2019 #ifdef SQLITE_ENABLE_API_ARMOR
2020   if( !sqlite3SafetyCheckOk(db) ){
2021     return SQLITE_MISUSE_BKPT;
2022   }
2023 #endif
2024   sqlite3_mutex_enter(db->mutex);
2025   if( mTrace==0 ) xTrace = 0;
2026   if( xTrace==0 ) mTrace = 0;
2027   db->mTrace = mTrace;
2028   db->xTrace = xTrace;
2029   db->pTraceArg = pArg;
2030   sqlite3_mutex_leave(db->mutex);
2031   return SQLITE_OK;
2032 }
2033 
2034 #ifndef SQLITE_OMIT_DEPRECATED
2035 /*
2036 ** Register a profile function.  The pArg from the previously registered
2037 ** profile function is returned.
2038 **
2039 ** A NULL profile function means that no profiling is executes.  A non-NULL
2040 ** profile is a pointer to a function that is invoked at the conclusion of
2041 ** each SQL statement that is run.
2042 */
2043 void *sqlite3_profile(
2044   sqlite3 *db,
2045   void (*xProfile)(void*,const char*,sqlite_uint64),
2046   void *pArg
2047 ){
2048   void *pOld;
2049 
2050 #ifdef SQLITE_ENABLE_API_ARMOR
2051   if( !sqlite3SafetyCheckOk(db) ){
2052     (void)SQLITE_MISUSE_BKPT;
2053     return 0;
2054   }
2055 #endif
2056   sqlite3_mutex_enter(db->mutex);
2057   pOld = db->pProfileArg;
2058   db->xProfile = xProfile;
2059   db->pProfileArg = pArg;
2060   db->mTrace &= SQLITE_TRACE_NONLEGACY_MASK;
2061   if( db->xProfile ) db->mTrace |= SQLITE_TRACE_XPROFILE;
2062   sqlite3_mutex_leave(db->mutex);
2063   return pOld;
2064 }
2065 #endif /* SQLITE_OMIT_DEPRECATED */
2066 #endif /* SQLITE_OMIT_TRACE */
2067 
2068 /*
2069 ** Register a function to be invoked when a transaction commits.
2070 ** If the invoked function returns non-zero, then the commit becomes a
2071 ** rollback.
2072 */
2073 void *sqlite3_commit_hook(
2074   sqlite3 *db,              /* Attach the hook to this database */
2075   int (*xCallback)(void*),  /* Function to invoke on each commit */
2076   void *pArg                /* Argument to the function */
2077 ){
2078   void *pOld;
2079 
2080 #ifdef SQLITE_ENABLE_API_ARMOR
2081   if( !sqlite3SafetyCheckOk(db) ){
2082     (void)SQLITE_MISUSE_BKPT;
2083     return 0;
2084   }
2085 #endif
2086   sqlite3_mutex_enter(db->mutex);
2087   pOld = db->pCommitArg;
2088   db->xCommitCallback = xCallback;
2089   db->pCommitArg = pArg;
2090   sqlite3_mutex_leave(db->mutex);
2091   return pOld;
2092 }
2093 
2094 /*
2095 ** Register a callback to be invoked each time a row is updated,
2096 ** inserted or deleted using this database connection.
2097 */
2098 void *sqlite3_update_hook(
2099   sqlite3 *db,              /* Attach the hook to this database */
2100   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
2101   void *pArg                /* Argument to the function */
2102 ){
2103   void *pRet;
2104 
2105 #ifdef SQLITE_ENABLE_API_ARMOR
2106   if( !sqlite3SafetyCheckOk(db) ){
2107     (void)SQLITE_MISUSE_BKPT;
2108     return 0;
2109   }
2110 #endif
2111   sqlite3_mutex_enter(db->mutex);
2112   pRet = db->pUpdateArg;
2113   db->xUpdateCallback = xCallback;
2114   db->pUpdateArg = pArg;
2115   sqlite3_mutex_leave(db->mutex);
2116   return pRet;
2117 }
2118 
2119 /*
2120 ** Register a callback to be invoked each time a transaction is rolled
2121 ** back by this database connection.
2122 */
2123 void *sqlite3_rollback_hook(
2124   sqlite3 *db,              /* Attach the hook to this database */
2125   void (*xCallback)(void*), /* Callback function */
2126   void *pArg                /* Argument to the function */
2127 ){
2128   void *pRet;
2129 
2130 #ifdef SQLITE_ENABLE_API_ARMOR
2131   if( !sqlite3SafetyCheckOk(db) ){
2132     (void)SQLITE_MISUSE_BKPT;
2133     return 0;
2134   }
2135 #endif
2136   sqlite3_mutex_enter(db->mutex);
2137   pRet = db->pRollbackArg;
2138   db->xRollbackCallback = xCallback;
2139   db->pRollbackArg = pArg;
2140   sqlite3_mutex_leave(db->mutex);
2141   return pRet;
2142 }
2143 
2144 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2145 /*
2146 ** Register a callback to be invoked each time a row is updated,
2147 ** inserted or deleted using this database connection.
2148 */
2149 void *sqlite3_preupdate_hook(
2150   sqlite3 *db,              /* Attach the hook to this database */
2151   void(*xCallback)(         /* Callback function */
2152     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
2153   void *pArg                /* First callback argument */
2154 ){
2155   void *pRet;
2156   sqlite3_mutex_enter(db->mutex);
2157   pRet = db->pPreUpdateArg;
2158   db->xPreUpdateCallback = xCallback;
2159   db->pPreUpdateArg = pArg;
2160   sqlite3_mutex_leave(db->mutex);
2161   return pRet;
2162 }
2163 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2164 
2165 #ifndef SQLITE_OMIT_WAL
2166 /*
2167 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2168 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2169 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2170 ** wal_autocheckpoint()).
2171 */
2172 int sqlite3WalDefaultHook(
2173   void *pClientData,     /* Argument */
2174   sqlite3 *db,           /* Connection */
2175   const char *zDb,       /* Database */
2176   int nFrame             /* Size of WAL */
2177 ){
2178   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2179     sqlite3BeginBenignMalloc();
2180     sqlite3_wal_checkpoint(db, zDb);
2181     sqlite3EndBenignMalloc();
2182   }
2183   return SQLITE_OK;
2184 }
2185 #endif /* SQLITE_OMIT_WAL */
2186 
2187 /*
2188 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2189 ** a database after committing a transaction if there are nFrame or
2190 ** more frames in the log file. Passing zero or a negative value as the
2191 ** nFrame parameter disables automatic checkpoints entirely.
2192 **
2193 ** The callback registered by this function replaces any existing callback
2194 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2195 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2196 ** configured by this function.
2197 */
2198 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2199 #ifdef SQLITE_OMIT_WAL
2200   UNUSED_PARAMETER(db);
2201   UNUSED_PARAMETER(nFrame);
2202 #else
2203 #ifdef SQLITE_ENABLE_API_ARMOR
2204   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2205 #endif
2206   if( nFrame>0 ){
2207     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2208   }else{
2209     sqlite3_wal_hook(db, 0, 0);
2210   }
2211 #endif
2212   return SQLITE_OK;
2213 }
2214 
2215 /*
2216 ** Register a callback to be invoked each time a transaction is written
2217 ** into the write-ahead-log by this database connection.
2218 */
2219 void *sqlite3_wal_hook(
2220   sqlite3 *db,                    /* Attach the hook to this db handle */
2221   int(*xCallback)(void *, sqlite3*, const char*, int),
2222   void *pArg                      /* First argument passed to xCallback() */
2223 ){
2224 #ifndef SQLITE_OMIT_WAL
2225   void *pRet;
2226 #ifdef SQLITE_ENABLE_API_ARMOR
2227   if( !sqlite3SafetyCheckOk(db) ){
2228     (void)SQLITE_MISUSE_BKPT;
2229     return 0;
2230   }
2231 #endif
2232   sqlite3_mutex_enter(db->mutex);
2233   pRet = db->pWalArg;
2234   db->xWalCallback = xCallback;
2235   db->pWalArg = pArg;
2236   sqlite3_mutex_leave(db->mutex);
2237   return pRet;
2238 #else
2239   return 0;
2240 #endif
2241 }
2242 
2243 /*
2244 ** Checkpoint database zDb.
2245 */
2246 int sqlite3_wal_checkpoint_v2(
2247   sqlite3 *db,                    /* Database handle */
2248   const char *zDb,                /* Name of attached database (or NULL) */
2249   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2250   int *pnLog,                     /* OUT: Size of WAL log in frames */
2251   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2252 ){
2253 #ifdef SQLITE_OMIT_WAL
2254   return SQLITE_OK;
2255 #else
2256   int rc;                         /* Return code */
2257   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2258 
2259 #ifdef SQLITE_ENABLE_API_ARMOR
2260   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2261 #endif
2262 
2263   /* Initialize the output variables to -1 in case an error occurs. */
2264   if( pnLog ) *pnLog = -1;
2265   if( pnCkpt ) *pnCkpt = -1;
2266 
2267   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2268   assert( SQLITE_CHECKPOINT_FULL==1 );
2269   assert( SQLITE_CHECKPOINT_RESTART==2 );
2270   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2271   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2272     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2273     ** mode: */
2274     return SQLITE_MISUSE;
2275   }
2276 
2277   sqlite3_mutex_enter(db->mutex);
2278   if( zDb && zDb[0] ){
2279     iDb = sqlite3FindDbName(db, zDb);
2280   }
2281   if( iDb<0 ){
2282     rc = SQLITE_ERROR;
2283     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2284   }else{
2285     db->busyHandler.nBusy = 0;
2286     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2287     sqlite3Error(db, rc);
2288   }
2289   rc = sqlite3ApiExit(db, rc);
2290 
2291   /* If there are no active statements, clear the interrupt flag at this
2292   ** point.  */
2293   if( db->nVdbeActive==0 ){
2294     db->u1.isInterrupted = 0;
2295   }
2296 
2297   sqlite3_mutex_leave(db->mutex);
2298   return rc;
2299 #endif
2300 }
2301 
2302 
2303 /*
2304 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2305 ** to contains a zero-length string, all attached databases are
2306 ** checkpointed.
2307 */
2308 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2309   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2310   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2311   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2312 }
2313 
2314 #ifndef SQLITE_OMIT_WAL
2315 /*
2316 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2317 ** not currently open in WAL mode.
2318 **
2319 ** If a transaction is open on the database being checkpointed, this
2320 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2321 ** an error occurs while running the checkpoint, an SQLite error code is
2322 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2323 **
2324 ** The mutex on database handle db should be held by the caller. The mutex
2325 ** associated with the specific b-tree being checkpointed is taken by
2326 ** this function while the checkpoint is running.
2327 **
2328 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2329 ** checkpointed. If an error is encountered it is returned immediately -
2330 ** no attempt is made to checkpoint any remaining databases.
2331 **
2332 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
2333 ** or TRUNCATE.
2334 */
2335 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2336   int rc = SQLITE_OK;             /* Return code */
2337   int i;                          /* Used to iterate through attached dbs */
2338   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2339 
2340   assert( sqlite3_mutex_held(db->mutex) );
2341   assert( !pnLog || *pnLog==-1 );
2342   assert( !pnCkpt || *pnCkpt==-1 );
2343 
2344   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2345     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2346       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2347       pnLog = 0;
2348       pnCkpt = 0;
2349       if( rc==SQLITE_BUSY ){
2350         bBusy = 1;
2351         rc = SQLITE_OK;
2352       }
2353     }
2354   }
2355 
2356   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2357 }
2358 #endif /* SQLITE_OMIT_WAL */
2359 
2360 /*
2361 ** This function returns true if main-memory should be used instead of
2362 ** a temporary file for transient pager files and statement journals.
2363 ** The value returned depends on the value of db->temp_store (runtime
2364 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2365 ** following table describes the relationship between these two values
2366 ** and this functions return value.
2367 **
2368 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2369 **   -----------------     --------------     ------------------------------
2370 **   0                     any                file      (return 0)
2371 **   1                     1                  file      (return 0)
2372 **   1                     2                  memory    (return 1)
2373 **   1                     0                  file      (return 0)
2374 **   2                     1                  file      (return 0)
2375 **   2                     2                  memory    (return 1)
2376 **   2                     0                  memory    (return 1)
2377 **   3                     any                memory    (return 1)
2378 */
2379 int sqlite3TempInMemory(const sqlite3 *db){
2380 #if SQLITE_TEMP_STORE==1
2381   return ( db->temp_store==2 );
2382 #endif
2383 #if SQLITE_TEMP_STORE==2
2384   return ( db->temp_store!=1 );
2385 #endif
2386 #if SQLITE_TEMP_STORE==3
2387   UNUSED_PARAMETER(db);
2388   return 1;
2389 #endif
2390 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2391   UNUSED_PARAMETER(db);
2392   return 0;
2393 #endif
2394 }
2395 
2396 /*
2397 ** Return UTF-8 encoded English language explanation of the most recent
2398 ** error.
2399 */
2400 const char *sqlite3_errmsg(sqlite3 *db){
2401   const char *z;
2402   if( !db ){
2403     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2404   }
2405   if( !sqlite3SafetyCheckSickOrOk(db) ){
2406     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2407   }
2408   sqlite3_mutex_enter(db->mutex);
2409   if( db->mallocFailed ){
2410     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2411   }else{
2412     testcase( db->pErr==0 );
2413     z = db->errCode ? (char*)sqlite3_value_text(db->pErr) : 0;
2414     assert( !db->mallocFailed );
2415     if( z==0 ){
2416       z = sqlite3ErrStr(db->errCode);
2417     }
2418   }
2419   sqlite3_mutex_leave(db->mutex);
2420   return z;
2421 }
2422 
2423 #ifndef SQLITE_OMIT_UTF16
2424 /*
2425 ** Return UTF-16 encoded English language explanation of the most recent
2426 ** error.
2427 */
2428 const void *sqlite3_errmsg16(sqlite3 *db){
2429   static const u16 outOfMem[] = {
2430     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2431   };
2432   static const u16 misuse[] = {
2433     'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
2434     'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
2435     'm', 'i', 's', 'u', 's', 'e', 0
2436   };
2437 
2438   const void *z;
2439   if( !db ){
2440     return (void *)outOfMem;
2441   }
2442   if( !sqlite3SafetyCheckSickOrOk(db) ){
2443     return (void *)misuse;
2444   }
2445   sqlite3_mutex_enter(db->mutex);
2446   if( db->mallocFailed ){
2447     z = (void *)outOfMem;
2448   }else{
2449     z = sqlite3_value_text16(db->pErr);
2450     if( z==0 ){
2451       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2452       z = sqlite3_value_text16(db->pErr);
2453     }
2454     /* A malloc() may have failed within the call to sqlite3_value_text16()
2455     ** above. If this is the case, then the db->mallocFailed flag needs to
2456     ** be cleared before returning. Do this directly, instead of via
2457     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2458     */
2459     sqlite3OomClear(db);
2460   }
2461   sqlite3_mutex_leave(db->mutex);
2462   return z;
2463 }
2464 #endif /* SQLITE_OMIT_UTF16 */
2465 
2466 /*
2467 ** Return the most recent error code generated by an SQLite routine. If NULL is
2468 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2469 */
2470 int sqlite3_errcode(sqlite3 *db){
2471   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2472     return SQLITE_MISUSE_BKPT;
2473   }
2474   if( !db || db->mallocFailed ){
2475     return SQLITE_NOMEM_BKPT;
2476   }
2477   return db->errCode & db->errMask;
2478 }
2479 int sqlite3_extended_errcode(sqlite3 *db){
2480   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2481     return SQLITE_MISUSE_BKPT;
2482   }
2483   if( !db || db->mallocFailed ){
2484     return SQLITE_NOMEM_BKPT;
2485   }
2486   return db->errCode;
2487 }
2488 int sqlite3_system_errno(sqlite3 *db){
2489   return db ? db->iSysErrno : 0;
2490 }
2491 
2492 /*
2493 ** Return a string that describes the kind of error specified in the
2494 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2495 ** function.
2496 */
2497 const char *sqlite3_errstr(int rc){
2498   return sqlite3ErrStr(rc);
2499 }
2500 
2501 /*
2502 ** Create a new collating function for database "db".  The name is zName
2503 ** and the encoding is enc.
2504 */
2505 static int createCollation(
2506   sqlite3* db,
2507   const char *zName,
2508   u8 enc,
2509   void* pCtx,
2510   int(*xCompare)(void*,int,const void*,int,const void*),
2511   void(*xDel)(void*)
2512 ){
2513   CollSeq *pColl;
2514   int enc2;
2515 
2516   assert( sqlite3_mutex_held(db->mutex) );
2517 
2518   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2519   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2520   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2521   */
2522   enc2 = enc;
2523   testcase( enc2==SQLITE_UTF16 );
2524   testcase( enc2==SQLITE_UTF16_ALIGNED );
2525   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2526     enc2 = SQLITE_UTF16NATIVE;
2527   }
2528   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2529     return SQLITE_MISUSE_BKPT;
2530   }
2531 
2532   /* Check if this call is removing or replacing an existing collation
2533   ** sequence. If so, and there are active VMs, return busy. If there
2534   ** are no active VMs, invalidate any pre-compiled statements.
2535   */
2536   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2537   if( pColl && pColl->xCmp ){
2538     if( db->nVdbeActive ){
2539       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2540         "unable to delete/modify collation sequence due to active statements");
2541       return SQLITE_BUSY;
2542     }
2543     sqlite3ExpirePreparedStatements(db, 0);
2544 
2545     /* If collation sequence pColl was created directly by a call to
2546     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2547     ** then any copies made by synthCollSeq() need to be invalidated.
2548     ** Also, collation destructor - CollSeq.xDel() - function may need
2549     ** to be called.
2550     */
2551     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2552       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2553       int j;
2554       for(j=0; j<3; j++){
2555         CollSeq *p = &aColl[j];
2556         if( p->enc==pColl->enc ){
2557           if( p->xDel ){
2558             p->xDel(p->pUser);
2559           }
2560           p->xCmp = 0;
2561         }
2562       }
2563     }
2564   }
2565 
2566   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2567   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2568   pColl->xCmp = xCompare;
2569   pColl->pUser = pCtx;
2570   pColl->xDel = xDel;
2571   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2572   sqlite3Error(db, SQLITE_OK);
2573   return SQLITE_OK;
2574 }
2575 
2576 
2577 /*
2578 ** This array defines hard upper bounds on limit values.  The
2579 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2580 ** #defines in sqlite3.h.
2581 */
2582 static const int aHardLimit[] = {
2583   SQLITE_MAX_LENGTH,
2584   SQLITE_MAX_SQL_LENGTH,
2585   SQLITE_MAX_COLUMN,
2586   SQLITE_MAX_EXPR_DEPTH,
2587   SQLITE_MAX_COMPOUND_SELECT,
2588   SQLITE_MAX_VDBE_OP,
2589   SQLITE_MAX_FUNCTION_ARG,
2590   SQLITE_MAX_ATTACHED,
2591   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2592   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2593   SQLITE_MAX_TRIGGER_DEPTH,
2594   SQLITE_MAX_WORKER_THREADS,
2595 };
2596 
2597 /*
2598 ** Make sure the hard limits are set to reasonable values
2599 */
2600 #if SQLITE_MAX_LENGTH<100
2601 # error SQLITE_MAX_LENGTH must be at least 100
2602 #endif
2603 #if SQLITE_MAX_SQL_LENGTH<100
2604 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2605 #endif
2606 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2607 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2608 #endif
2609 #if SQLITE_MAX_COMPOUND_SELECT<2
2610 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2611 #endif
2612 #if SQLITE_MAX_VDBE_OP<40
2613 # error SQLITE_MAX_VDBE_OP must be at least 40
2614 #endif
2615 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2616 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2617 #endif
2618 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2619 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2620 #endif
2621 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2622 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2623 #endif
2624 #if SQLITE_MAX_COLUMN>32767
2625 # error SQLITE_MAX_COLUMN must not exceed 32767
2626 #endif
2627 #if SQLITE_MAX_TRIGGER_DEPTH<1
2628 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2629 #endif
2630 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2631 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2632 #endif
2633 
2634 
2635 /*
2636 ** Change the value of a limit.  Report the old value.
2637 ** If an invalid limit index is supplied, report -1.
2638 ** Make no changes but still report the old value if the
2639 ** new limit is negative.
2640 **
2641 ** A new lower limit does not shrink existing constructs.
2642 ** It merely prevents new constructs that exceed the limit
2643 ** from forming.
2644 */
2645 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2646   int oldLimit;
2647 
2648 #ifdef SQLITE_ENABLE_API_ARMOR
2649   if( !sqlite3SafetyCheckOk(db) ){
2650     (void)SQLITE_MISUSE_BKPT;
2651     return -1;
2652   }
2653 #endif
2654 
2655   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2656   ** there is a hard upper bound set at compile-time by a C preprocessor
2657   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2658   ** "_MAX_".)
2659   */
2660   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2661   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2662   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2663   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2664   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2665   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2666   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2667   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2668   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2669                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2670   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2671   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2672   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2673   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2674 
2675 
2676   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2677     return -1;
2678   }
2679   oldLimit = db->aLimit[limitId];
2680   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2681     if( newLimit>aHardLimit[limitId] ){
2682       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2683     }
2684     db->aLimit[limitId] = newLimit;
2685   }
2686   return oldLimit;                     /* IMP: R-53341-35419 */
2687 }
2688 
2689 /*
2690 ** This function is used to parse both URIs and non-URI filenames passed by the
2691 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2692 ** URIs specified as part of ATTACH statements.
2693 **
2694 ** The first argument to this function is the name of the VFS to use (or
2695 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2696 ** query parameter. The second argument contains the URI (or non-URI filename)
2697 ** itself. When this function is called the *pFlags variable should contain
2698 ** the default flags to open the database handle with. The value stored in
2699 ** *pFlags may be updated before returning if the URI filename contains
2700 ** "cache=xxx" or "mode=xxx" query parameters.
2701 **
2702 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2703 ** the VFS that should be used to open the database file. *pzFile is set to
2704 ** point to a buffer containing the name of the file to open. It is the
2705 ** responsibility of the caller to eventually call sqlite3_free() to release
2706 ** this buffer.
2707 **
2708 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2709 ** may be set to point to a buffer containing an English language error
2710 ** message. It is the responsibility of the caller to eventually release
2711 ** this buffer by calling sqlite3_free().
2712 */
2713 int sqlite3ParseUri(
2714   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2715   const char *zUri,               /* Nul-terminated URI to parse */
2716   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2717   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2718   char **pzFile,                  /* OUT: Filename component of URI */
2719   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2720 ){
2721   int rc = SQLITE_OK;
2722   unsigned int flags = *pFlags;
2723   const char *zVfs = zDefaultVfs;
2724   char *zFile;
2725   char c;
2726   int nUri = sqlite3Strlen30(zUri);
2727 
2728   assert( *pzErrMsg==0 );
2729 
2730   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2731             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2732    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2733   ){
2734     char *zOpt;
2735     int eState;                   /* Parser state when parsing URI */
2736     int iIn;                      /* Input character index */
2737     int iOut = 0;                 /* Output character index */
2738     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2739 
2740     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2741     ** method that there may be extra parameters following the file-name.  */
2742     flags |= SQLITE_OPEN_URI;
2743 
2744     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2745     zFile = sqlite3_malloc64(nByte);
2746     if( !zFile ) return SQLITE_NOMEM_BKPT;
2747 
2748     iIn = 5;
2749 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2750     if( strncmp(zUri+5, "///", 3)==0 ){
2751       iIn = 7;
2752       /* The following condition causes URIs with five leading / characters
2753       ** like file://///host/path to be converted into UNCs like //host/path.
2754       ** The correct URI for that UNC has only two or four leading / characters
2755       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2756       ** common error, we are told, so we handle it as a special case. */
2757       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2758     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2759       iIn = 16;
2760     }
2761 #else
2762     /* Discard the scheme and authority segments of the URI. */
2763     if( zUri[5]=='/' && zUri[6]=='/' ){
2764       iIn = 7;
2765       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2766       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2767         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2768             iIn-7, &zUri[7]);
2769         rc = SQLITE_ERROR;
2770         goto parse_uri_out;
2771       }
2772     }
2773 #endif
2774 
2775     /* Copy the filename and any query parameters into the zFile buffer.
2776     ** Decode %HH escape codes along the way.
2777     **
2778     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2779     ** on the parsing context. As follows:
2780     **
2781     **   0: Parsing file-name.
2782     **   1: Parsing name section of a name=value query parameter.
2783     **   2: Parsing value section of a name=value query parameter.
2784     */
2785     eState = 0;
2786     while( (c = zUri[iIn])!=0 && c!='#' ){
2787       iIn++;
2788       if( c=='%'
2789        && sqlite3Isxdigit(zUri[iIn])
2790        && sqlite3Isxdigit(zUri[iIn+1])
2791       ){
2792         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2793         octet += sqlite3HexToInt(zUri[iIn++]);
2794 
2795         assert( octet>=0 && octet<256 );
2796         if( octet==0 ){
2797 #ifndef SQLITE_ENABLE_URI_00_ERROR
2798           /* This branch is taken when "%00" appears within the URI. In this
2799           ** case we ignore all text in the remainder of the path, name or
2800           ** value currently being parsed. So ignore the current character
2801           ** and skip to the next "?", "=" or "&", as appropriate. */
2802           while( (c = zUri[iIn])!=0 && c!='#'
2803               && (eState!=0 || c!='?')
2804               && (eState!=1 || (c!='=' && c!='&'))
2805               && (eState!=2 || c!='&')
2806           ){
2807             iIn++;
2808           }
2809           continue;
2810 #else
2811           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2812           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2813           rc = SQLITE_ERROR;
2814           goto parse_uri_out;
2815 #endif
2816         }
2817         c = octet;
2818       }else if( eState==1 && (c=='&' || c=='=') ){
2819         if( zFile[iOut-1]==0 ){
2820           /* An empty option name. Ignore this option altogether. */
2821           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2822           continue;
2823         }
2824         if( c=='&' ){
2825           zFile[iOut++] = '\0';
2826         }else{
2827           eState = 2;
2828         }
2829         c = 0;
2830       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2831         c = 0;
2832         eState = 1;
2833       }
2834       zFile[iOut++] = c;
2835     }
2836     if( eState==1 ) zFile[iOut++] = '\0';
2837     zFile[iOut++] = '\0';
2838     zFile[iOut++] = '\0';
2839 
2840     /* Check if there were any options specified that should be interpreted
2841     ** here. Options that are interpreted here include "vfs" and those that
2842     ** correspond to flags that may be passed to the sqlite3_open_v2()
2843     ** method. */
2844     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2845     while( zOpt[0] ){
2846       int nOpt = sqlite3Strlen30(zOpt);
2847       char *zVal = &zOpt[nOpt+1];
2848       int nVal = sqlite3Strlen30(zVal);
2849 
2850       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2851         zVfs = zVal;
2852       }else{
2853         struct OpenMode {
2854           const char *z;
2855           int mode;
2856         } *aMode = 0;
2857         char *zModeType = 0;
2858         int mask = 0;
2859         int limit = 0;
2860 
2861         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2862           static struct OpenMode aCacheMode[] = {
2863             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2864             { "private", SQLITE_OPEN_PRIVATECACHE },
2865             { 0, 0 }
2866           };
2867 
2868           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2869           aMode = aCacheMode;
2870           limit = mask;
2871           zModeType = "cache";
2872         }
2873         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2874           static struct OpenMode aOpenMode[] = {
2875             { "ro",  SQLITE_OPEN_READONLY },
2876             { "rw",  SQLITE_OPEN_READWRITE },
2877             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2878             { "memory", SQLITE_OPEN_MEMORY },
2879             { 0, 0 }
2880           };
2881 
2882           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2883                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2884           aMode = aOpenMode;
2885           limit = mask & flags;
2886           zModeType = "access";
2887         }
2888 
2889         if( aMode ){
2890           int i;
2891           int mode = 0;
2892           for(i=0; aMode[i].z; i++){
2893             const char *z = aMode[i].z;
2894             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2895               mode = aMode[i].mode;
2896               break;
2897             }
2898           }
2899           if( mode==0 ){
2900             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2901             rc = SQLITE_ERROR;
2902             goto parse_uri_out;
2903           }
2904           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2905             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2906                                         zModeType, zVal);
2907             rc = SQLITE_PERM;
2908             goto parse_uri_out;
2909           }
2910           flags = (flags & ~mask) | mode;
2911         }
2912       }
2913 
2914       zOpt = &zVal[nVal+1];
2915     }
2916 
2917   }else{
2918     zFile = sqlite3_malloc64(nUri+2);
2919     if( !zFile ) return SQLITE_NOMEM_BKPT;
2920     if( nUri ){
2921       memcpy(zFile, zUri, nUri);
2922     }
2923     zFile[nUri] = '\0';
2924     zFile[nUri+1] = '\0';
2925     flags &= ~SQLITE_OPEN_URI;
2926   }
2927 
2928   *ppVfs = sqlite3_vfs_find(zVfs);
2929   if( *ppVfs==0 ){
2930     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2931     rc = SQLITE_ERROR;
2932   }
2933  parse_uri_out:
2934   if( rc!=SQLITE_OK ){
2935     sqlite3_free(zFile);
2936     zFile = 0;
2937   }
2938   *pFlags = flags;
2939   *pzFile = zFile;
2940   return rc;
2941 }
2942 
2943 #if defined(SQLITE_HAS_CODEC)
2944 /*
2945 ** Process URI filename query parameters relevant to the SQLite Encryption
2946 ** Extension.  Return true if any of the relevant query parameters are
2947 ** seen and return false if not.
2948 */
2949 int sqlite3CodecQueryParameters(
2950   sqlite3 *db,           /* Database connection */
2951   const char *zDb,       /* Which schema is being created/attached */
2952   const char *zUri       /* URI filename */
2953 ){
2954   const char *zKey;
2955   if( (zKey = sqlite3_uri_parameter(zUri, "hexkey"))!=0 && zKey[0] ){
2956     u8 iByte;
2957     int i;
2958     char zDecoded[40];
2959     for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
2960       iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
2961       if( (i&1)!=0 ) zDecoded[i/2] = iByte;
2962     }
2963     sqlite3_key_v2(db, zDb, zDecoded, i/2);
2964     return 1;
2965   }else if( (zKey = sqlite3_uri_parameter(zUri, "key"))!=0 ){
2966     sqlite3_key_v2(db, zDb, zKey, sqlite3Strlen30(zKey));
2967     return 1;
2968   }else if( (zKey = sqlite3_uri_parameter(zUri, "textkey"))!=0 ){
2969     sqlite3_key_v2(db, zDb, zKey, -1);
2970     return 1;
2971   }else{
2972     return 0;
2973   }
2974 }
2975 #endif
2976 
2977 
2978 /*
2979 ** This routine does the work of opening a database on behalf of
2980 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2981 ** is UTF-8 encoded.
2982 */
2983 static int openDatabase(
2984   const char *zFilename, /* Database filename UTF-8 encoded */
2985   sqlite3 **ppDb,        /* OUT: Returned database handle */
2986   unsigned int flags,    /* Operational flags */
2987   const char *zVfs       /* Name of the VFS to use */
2988 ){
2989   sqlite3 *db;                    /* Store allocated handle here */
2990   int rc;                         /* Return code */
2991   int isThreadsafe;               /* True for threadsafe connections */
2992   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2993   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2994 
2995 #ifdef SQLITE_ENABLE_API_ARMOR
2996   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2997 #endif
2998   *ppDb = 0;
2999 #ifndef SQLITE_OMIT_AUTOINIT
3000   rc = sqlite3_initialize();
3001   if( rc ) return rc;
3002 #endif
3003 
3004   if( sqlite3GlobalConfig.bCoreMutex==0 ){
3005     isThreadsafe = 0;
3006   }else if( flags & SQLITE_OPEN_NOMUTEX ){
3007     isThreadsafe = 0;
3008   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
3009     isThreadsafe = 1;
3010   }else{
3011     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
3012   }
3013 
3014   if( flags & SQLITE_OPEN_PRIVATECACHE ){
3015     flags &= ~SQLITE_OPEN_SHAREDCACHE;
3016   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
3017     flags |= SQLITE_OPEN_SHAREDCACHE;
3018   }
3019 
3020   /* Remove harmful bits from the flags parameter
3021   **
3022   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
3023   ** dealt with in the previous code block.  Besides these, the only
3024   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
3025   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
3026   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
3027   ** off all other flags.
3028   */
3029   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
3030                SQLITE_OPEN_EXCLUSIVE |
3031                SQLITE_OPEN_MAIN_DB |
3032                SQLITE_OPEN_TEMP_DB |
3033                SQLITE_OPEN_TRANSIENT_DB |
3034                SQLITE_OPEN_MAIN_JOURNAL |
3035                SQLITE_OPEN_TEMP_JOURNAL |
3036                SQLITE_OPEN_SUBJOURNAL |
3037                SQLITE_OPEN_MASTER_JOURNAL |
3038                SQLITE_OPEN_NOMUTEX |
3039                SQLITE_OPEN_FULLMUTEX |
3040                SQLITE_OPEN_WAL
3041              );
3042 
3043   /* Allocate the sqlite data structure */
3044   db = sqlite3MallocZero( sizeof(sqlite3) );
3045   if( db==0 ) goto opendb_out;
3046   if( isThreadsafe
3047 #ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
3048    || sqlite3GlobalConfig.bCoreMutex
3049 #endif
3050   ){
3051     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
3052     if( db->mutex==0 ){
3053       sqlite3_free(db);
3054       db = 0;
3055       goto opendb_out;
3056     }
3057     if( isThreadsafe==0 ){
3058       sqlite3MutexWarnOnContention(db->mutex);
3059     }
3060   }
3061   sqlite3_mutex_enter(db->mutex);
3062   db->errMask = 0xff;
3063   db->nDb = 2;
3064   db->magic = SQLITE_MAGIC_BUSY;
3065   db->aDb = db->aDbStatic;
3066   db->lookaside.bDisable = 1;
3067 
3068   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
3069   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
3070   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
3071   db->autoCommit = 1;
3072   db->nextAutovac = -1;
3073   db->szMmap = sqlite3GlobalConfig.szMmap;
3074   db->nextPagesize = 0;
3075   db->nMaxSorterMmap = 0x7FFFFFFF;
3076   db->flags |= SQLITE_ShortColNames
3077                  | SQLITE_EnableTrigger
3078                  | SQLITE_EnableView
3079                  | SQLITE_CacheSpill
3080 
3081 /* The SQLITE_DQS compile-time option determines the default settings
3082 ** for SQLITE_DBCONFIG_DQS_DDL and SQLITE_DBCONFIG_DQS_DML.
3083 **
3084 **    SQLITE_DQS     SQLITE_DBCONFIG_DQS_DDL    SQLITE_DBCONFIG_DQS_DML
3085 **    ----------     -----------------------    -----------------------
3086 **     undefined               on                          on
3087 **         3                   on                          on
3088 **         2                   on                         off
3089 **         1                  off                          on
3090 **         0                  off                         off
3091 **
3092 ** Legacy behavior is 3 (double-quoted string literals are allowed anywhere)
3093 ** and so that is the default.  But developers are encouranged to use
3094 ** -DSQLITE_DQS=0 (best) or -DSQLITE_DQS=1 (second choice) if possible.
3095 */
3096 #if !defined(SQLITE_DQS)
3097 # define SQLITE_DQS 3
3098 #endif
3099 #if (SQLITE_DQS&1)==1
3100                  | SQLITE_DqsDML
3101 #endif
3102 #if (SQLITE_DQS&2)==2
3103                  | SQLITE_DqsDDL
3104 #endif
3105 
3106 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
3107                  | SQLITE_AutoIndex
3108 #endif
3109 #if SQLITE_DEFAULT_CKPTFULLFSYNC
3110                  | SQLITE_CkptFullFSync
3111 #endif
3112 #if SQLITE_DEFAULT_FILE_FORMAT<4
3113                  | SQLITE_LegacyFileFmt
3114 #endif
3115 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
3116                  | SQLITE_LoadExtension
3117 #endif
3118 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
3119                  | SQLITE_RecTriggers
3120 #endif
3121 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
3122                  | SQLITE_ForeignKeys
3123 #endif
3124 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
3125                  | SQLITE_ReverseOrder
3126 #endif
3127 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
3128                  | SQLITE_CellSizeCk
3129 #endif
3130 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
3131                  | SQLITE_Fts3Tokenizer
3132 #endif
3133 #if defined(SQLITE_ENABLE_QPSG)
3134                  | SQLITE_EnableQPSG
3135 #endif
3136 #if defined(SQLITE_DEFAULT_DEFENSIVE)
3137                  | SQLITE_Defensive
3138 #endif
3139       ;
3140   sqlite3HashInit(&db->aCollSeq);
3141 #ifndef SQLITE_OMIT_VIRTUALTABLE
3142   sqlite3HashInit(&db->aModule);
3143 #endif
3144 
3145   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
3146   ** and UTF-16, so add a version for each to avoid any unnecessary
3147   ** conversions. The only error that can occur here is a malloc() failure.
3148   **
3149   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
3150   ** functions:
3151   */
3152   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
3153   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
3154   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
3155   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
3156   createCollation(db, "RTRIM", SQLITE_UTF8, 0, rtrimCollFunc, 0);
3157   if( db->mallocFailed ){
3158     goto opendb_out;
3159   }
3160   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
3161   ** strings is BINARY.
3162   */
3163   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
3164   assert( db->pDfltColl!=0 );
3165 
3166   /* Parse the filename/URI argument
3167   **
3168   ** Only allow sensible combinations of bits in the flags argument.
3169   ** Throw an error if any non-sense combination is used.  If we
3170   ** do not block illegal combinations here, it could trigger
3171   ** assert() statements in deeper layers.  Sensible combinations
3172   ** are:
3173   **
3174   **  1:  SQLITE_OPEN_READONLY
3175   **  2:  SQLITE_OPEN_READWRITE
3176   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
3177   */
3178   db->openFlags = flags;
3179   assert( SQLITE_OPEN_READONLY  == 0x01 );
3180   assert( SQLITE_OPEN_READWRITE == 0x02 );
3181   assert( SQLITE_OPEN_CREATE    == 0x04 );
3182   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
3183   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
3184   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
3185   if( ((1<<(flags&7)) & 0x46)==0 ){
3186     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
3187   }else{
3188     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
3189   }
3190   if( rc!=SQLITE_OK ){
3191     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
3192     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
3193     sqlite3_free(zErrMsg);
3194     goto opendb_out;
3195   }
3196 
3197   /* Open the backend database driver */
3198   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
3199                         flags | SQLITE_OPEN_MAIN_DB);
3200   if( rc!=SQLITE_OK ){
3201     if( rc==SQLITE_IOERR_NOMEM ){
3202       rc = SQLITE_NOMEM_BKPT;
3203     }
3204     sqlite3Error(db, rc);
3205     goto opendb_out;
3206   }
3207   sqlite3BtreeEnter(db->aDb[0].pBt);
3208   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
3209   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
3210   sqlite3BtreeLeave(db->aDb[0].pBt);
3211   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
3212 
3213   /* The default safety_level for the main database is FULL; for the temp
3214   ** database it is OFF. This matches the pager layer defaults.
3215   */
3216   db->aDb[0].zDbSName = "main";
3217   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
3218   db->aDb[1].zDbSName = "temp";
3219   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
3220 
3221   db->magic = SQLITE_MAGIC_OPEN;
3222   if( db->mallocFailed ){
3223     goto opendb_out;
3224   }
3225 
3226   /* Register all built-in functions, but do not attempt to read the
3227   ** database schema yet. This is delayed until the first time the database
3228   ** is accessed.
3229   */
3230   sqlite3Error(db, SQLITE_OK);
3231   sqlite3RegisterPerConnectionBuiltinFunctions(db);
3232   rc = sqlite3_errcode(db);
3233 
3234 #ifdef SQLITE_ENABLE_FTS5
3235   /* Register any built-in FTS5 module before loading the automatic
3236   ** extensions. This allows automatic extensions to register FTS5
3237   ** tokenizers and auxiliary functions.  */
3238   if( !db->mallocFailed && rc==SQLITE_OK ){
3239     rc = sqlite3Fts5Init(db);
3240   }
3241 #endif
3242 
3243   /* Load automatic extensions - extensions that have been registered
3244   ** using the sqlite3_automatic_extension() API.
3245   */
3246   if( rc==SQLITE_OK ){
3247     sqlite3AutoLoadExtensions(db);
3248     rc = sqlite3_errcode(db);
3249     if( rc!=SQLITE_OK ){
3250       goto opendb_out;
3251     }
3252   }
3253 
3254 #ifdef SQLITE_ENABLE_FTS1
3255   if( !db->mallocFailed ){
3256     extern int sqlite3Fts1Init(sqlite3*);
3257     rc = sqlite3Fts1Init(db);
3258   }
3259 #endif
3260 
3261 #ifdef SQLITE_ENABLE_FTS2
3262   if( !db->mallocFailed && rc==SQLITE_OK ){
3263     extern int sqlite3Fts2Init(sqlite3*);
3264     rc = sqlite3Fts2Init(db);
3265   }
3266 #endif
3267 
3268 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3269   if( !db->mallocFailed && rc==SQLITE_OK ){
3270     rc = sqlite3Fts3Init(db);
3271   }
3272 #endif
3273 
3274 #if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
3275   if( !db->mallocFailed && rc==SQLITE_OK ){
3276     rc = sqlite3IcuInit(db);
3277   }
3278 #endif
3279 
3280 #ifdef SQLITE_ENABLE_RTREE
3281   if( !db->mallocFailed && rc==SQLITE_OK){
3282     rc = sqlite3RtreeInit(db);
3283   }
3284 #endif
3285 
3286 #ifdef SQLITE_ENABLE_DBPAGE_VTAB
3287   if( !db->mallocFailed && rc==SQLITE_OK){
3288     rc = sqlite3DbpageRegister(db);
3289   }
3290 #endif
3291 
3292 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3293   if( !db->mallocFailed && rc==SQLITE_OK){
3294     rc = sqlite3DbstatRegister(db);
3295   }
3296 #endif
3297 
3298 #ifdef SQLITE_ENABLE_JSON1
3299   if( !db->mallocFailed && rc==SQLITE_OK){
3300     rc = sqlite3Json1Init(db);
3301   }
3302 #endif
3303 
3304 #ifdef SQLITE_ENABLE_STMTVTAB
3305   if( !db->mallocFailed && rc==SQLITE_OK){
3306     rc = sqlite3StmtVtabInit(db);
3307   }
3308 #endif
3309 
3310   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3311   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3312   ** mode.  Doing nothing at all also makes NORMAL the default.
3313   */
3314 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3315   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3316   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3317                           SQLITE_DEFAULT_LOCKING_MODE);
3318 #endif
3319 
3320   if( rc ) sqlite3Error(db, rc);
3321 
3322   /* Enable the lookaside-malloc subsystem */
3323   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3324                         sqlite3GlobalConfig.nLookaside);
3325 
3326   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3327 
3328 opendb_out:
3329   if( db ){
3330     assert( db->mutex!=0 || isThreadsafe==0
3331            || sqlite3GlobalConfig.bFullMutex==0 );
3332     sqlite3_mutex_leave(db->mutex);
3333   }
3334   rc = sqlite3_errcode(db);
3335   assert( db!=0 || rc==SQLITE_NOMEM );
3336   if( rc==SQLITE_NOMEM ){
3337     sqlite3_close(db);
3338     db = 0;
3339   }else if( rc!=SQLITE_OK ){
3340     db->magic = SQLITE_MAGIC_SICK;
3341   }
3342   *ppDb = db;
3343 #ifdef SQLITE_ENABLE_SQLLOG
3344   if( sqlite3GlobalConfig.xSqllog ){
3345     /* Opening a db handle. Fourth parameter is passed 0. */
3346     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3347     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3348   }
3349 #endif
3350 #if defined(SQLITE_HAS_CODEC)
3351   if( rc==SQLITE_OK ) sqlite3CodecQueryParameters(db, 0, zOpen);
3352 #endif
3353   sqlite3_free(zOpen);
3354   return rc & 0xff;
3355 }
3356 
3357 
3358 /*
3359 ** Open a new database handle.
3360 */
3361 int sqlite3_open(
3362   const char *zFilename,
3363   sqlite3 **ppDb
3364 ){
3365   return openDatabase(zFilename, ppDb,
3366                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3367 }
3368 int sqlite3_open_v2(
3369   const char *filename,   /* Database filename (UTF-8) */
3370   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3371   int flags,              /* Flags */
3372   const char *zVfs        /* Name of VFS module to use */
3373 ){
3374   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3375 }
3376 
3377 #ifndef SQLITE_OMIT_UTF16
3378 /*
3379 ** Open a new database handle.
3380 */
3381 int sqlite3_open16(
3382   const void *zFilename,
3383   sqlite3 **ppDb
3384 ){
3385   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3386   sqlite3_value *pVal;
3387   int rc;
3388 
3389 #ifdef SQLITE_ENABLE_API_ARMOR
3390   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3391 #endif
3392   *ppDb = 0;
3393 #ifndef SQLITE_OMIT_AUTOINIT
3394   rc = sqlite3_initialize();
3395   if( rc ) return rc;
3396 #endif
3397   if( zFilename==0 ) zFilename = "\000\000";
3398   pVal = sqlite3ValueNew(0);
3399   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3400   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3401   if( zFilename8 ){
3402     rc = openDatabase(zFilename8, ppDb,
3403                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3404     assert( *ppDb || rc==SQLITE_NOMEM );
3405     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3406       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3407     }
3408   }else{
3409     rc = SQLITE_NOMEM_BKPT;
3410   }
3411   sqlite3ValueFree(pVal);
3412 
3413   return rc & 0xff;
3414 }
3415 #endif /* SQLITE_OMIT_UTF16 */
3416 
3417 /*
3418 ** Register a new collation sequence with the database handle db.
3419 */
3420 int sqlite3_create_collation(
3421   sqlite3* db,
3422   const char *zName,
3423   int enc,
3424   void* pCtx,
3425   int(*xCompare)(void*,int,const void*,int,const void*)
3426 ){
3427   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3428 }
3429 
3430 /*
3431 ** Register a new collation sequence with the database handle db.
3432 */
3433 int sqlite3_create_collation_v2(
3434   sqlite3* db,
3435   const char *zName,
3436   int enc,
3437   void* pCtx,
3438   int(*xCompare)(void*,int,const void*,int,const void*),
3439   void(*xDel)(void*)
3440 ){
3441   int rc;
3442 
3443 #ifdef SQLITE_ENABLE_API_ARMOR
3444   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3445 #endif
3446   sqlite3_mutex_enter(db->mutex);
3447   assert( !db->mallocFailed );
3448   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3449   rc = sqlite3ApiExit(db, rc);
3450   sqlite3_mutex_leave(db->mutex);
3451   return rc;
3452 }
3453 
3454 #ifndef SQLITE_OMIT_UTF16
3455 /*
3456 ** Register a new collation sequence with the database handle db.
3457 */
3458 int sqlite3_create_collation16(
3459   sqlite3* db,
3460   const void *zName,
3461   int enc,
3462   void* pCtx,
3463   int(*xCompare)(void*,int,const void*,int,const void*)
3464 ){
3465   int rc = SQLITE_OK;
3466   char *zName8;
3467 
3468 #ifdef SQLITE_ENABLE_API_ARMOR
3469   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3470 #endif
3471   sqlite3_mutex_enter(db->mutex);
3472   assert( !db->mallocFailed );
3473   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3474   if( zName8 ){
3475     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3476     sqlite3DbFree(db, zName8);
3477   }
3478   rc = sqlite3ApiExit(db, rc);
3479   sqlite3_mutex_leave(db->mutex);
3480   return rc;
3481 }
3482 #endif /* SQLITE_OMIT_UTF16 */
3483 
3484 /*
3485 ** Register a collation sequence factory callback with the database handle
3486 ** db. Replace any previously installed collation sequence factory.
3487 */
3488 int sqlite3_collation_needed(
3489   sqlite3 *db,
3490   void *pCollNeededArg,
3491   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3492 ){
3493 #ifdef SQLITE_ENABLE_API_ARMOR
3494   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3495 #endif
3496   sqlite3_mutex_enter(db->mutex);
3497   db->xCollNeeded = xCollNeeded;
3498   db->xCollNeeded16 = 0;
3499   db->pCollNeededArg = pCollNeededArg;
3500   sqlite3_mutex_leave(db->mutex);
3501   return SQLITE_OK;
3502 }
3503 
3504 #ifndef SQLITE_OMIT_UTF16
3505 /*
3506 ** Register a collation sequence factory callback with the database handle
3507 ** db. Replace any previously installed collation sequence factory.
3508 */
3509 int sqlite3_collation_needed16(
3510   sqlite3 *db,
3511   void *pCollNeededArg,
3512   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3513 ){
3514 #ifdef SQLITE_ENABLE_API_ARMOR
3515   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3516 #endif
3517   sqlite3_mutex_enter(db->mutex);
3518   db->xCollNeeded = 0;
3519   db->xCollNeeded16 = xCollNeeded16;
3520   db->pCollNeededArg = pCollNeededArg;
3521   sqlite3_mutex_leave(db->mutex);
3522   return SQLITE_OK;
3523 }
3524 #endif /* SQLITE_OMIT_UTF16 */
3525 
3526 #ifndef SQLITE_OMIT_DEPRECATED
3527 /*
3528 ** This function is now an anachronism. It used to be used to recover from a
3529 ** malloc() failure, but SQLite now does this automatically.
3530 */
3531 int sqlite3_global_recover(void){
3532   return SQLITE_OK;
3533 }
3534 #endif
3535 
3536 /*
3537 ** Test to see whether or not the database connection is in autocommit
3538 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3539 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3540 ** by the next COMMIT or ROLLBACK.
3541 */
3542 int sqlite3_get_autocommit(sqlite3 *db){
3543 #ifdef SQLITE_ENABLE_API_ARMOR
3544   if( !sqlite3SafetyCheckOk(db) ){
3545     (void)SQLITE_MISUSE_BKPT;
3546     return 0;
3547   }
3548 #endif
3549   return db->autoCommit;
3550 }
3551 
3552 /*
3553 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3554 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3555 ** constants.  They serve two purposes:
3556 **
3557 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3558 **       to detect when version error conditions occurs.
3559 **
3560 **   2.  Invoke sqlite3_log() to provide the source code location where
3561 **       a low-level error is first detected.
3562 */
3563 int sqlite3ReportError(int iErr, int lineno, const char *zType){
3564   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3565               zType, lineno, 20+sqlite3_sourceid());
3566   return iErr;
3567 }
3568 int sqlite3CorruptError(int lineno){
3569   testcase( sqlite3GlobalConfig.xLog!=0 );
3570   return sqlite3ReportError(SQLITE_CORRUPT, lineno, "database corruption");
3571 }
3572 int sqlite3MisuseError(int lineno){
3573   testcase( sqlite3GlobalConfig.xLog!=0 );
3574   return sqlite3ReportError(SQLITE_MISUSE, lineno, "misuse");
3575 }
3576 int sqlite3CantopenError(int lineno){
3577   testcase( sqlite3GlobalConfig.xLog!=0 );
3578   return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3579 }
3580 #ifdef SQLITE_DEBUG
3581 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3582   char zMsg[100];
3583   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3584   testcase( sqlite3GlobalConfig.xLog!=0 );
3585   return sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
3586 }
3587 int sqlite3NomemError(int lineno){
3588   testcase( sqlite3GlobalConfig.xLog!=0 );
3589   return sqlite3ReportError(SQLITE_NOMEM, lineno, "OOM");
3590 }
3591 int sqlite3IoerrnomemError(int lineno){
3592   testcase( sqlite3GlobalConfig.xLog!=0 );
3593   return sqlite3ReportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3594 }
3595 #endif
3596 
3597 #ifndef SQLITE_OMIT_DEPRECATED
3598 /*
3599 ** This is a convenience routine that makes sure that all thread-specific
3600 ** data for this thread has been deallocated.
3601 **
3602 ** SQLite no longer uses thread-specific data so this routine is now a
3603 ** no-op.  It is retained for historical compatibility.
3604 */
3605 void sqlite3_thread_cleanup(void){
3606 }
3607 #endif
3608 
3609 /*
3610 ** Return meta information about a specific column of a database table.
3611 ** See comment in sqlite3.h (sqlite.h.in) for details.
3612 */
3613 int sqlite3_table_column_metadata(
3614   sqlite3 *db,                /* Connection handle */
3615   const char *zDbName,        /* Database name or NULL */
3616   const char *zTableName,     /* Table name */
3617   const char *zColumnName,    /* Column name */
3618   char const **pzDataType,    /* OUTPUT: Declared data type */
3619   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3620   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3621   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3622   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3623 ){
3624   int rc;
3625   char *zErrMsg = 0;
3626   Table *pTab = 0;
3627   Column *pCol = 0;
3628   int iCol = 0;
3629   char const *zDataType = 0;
3630   char const *zCollSeq = 0;
3631   int notnull = 0;
3632   int primarykey = 0;
3633   int autoinc = 0;
3634 
3635 
3636 #ifdef SQLITE_ENABLE_API_ARMOR
3637   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3638     return SQLITE_MISUSE_BKPT;
3639   }
3640 #endif
3641 
3642   /* Ensure the database schema has been loaded */
3643   sqlite3_mutex_enter(db->mutex);
3644   sqlite3BtreeEnterAll(db);
3645   rc = sqlite3Init(db, &zErrMsg);
3646   if( SQLITE_OK!=rc ){
3647     goto error_out;
3648   }
3649 
3650   /* Locate the table in question */
3651   pTab = sqlite3FindTable(db, zTableName, zDbName);
3652   if( !pTab || pTab->pSelect ){
3653     pTab = 0;
3654     goto error_out;
3655   }
3656 
3657   /* Find the column for which info is requested */
3658   if( zColumnName==0 ){
3659     /* Query for existance of table only */
3660   }else{
3661     for(iCol=0; iCol<pTab->nCol; iCol++){
3662       pCol = &pTab->aCol[iCol];
3663       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3664         break;
3665       }
3666     }
3667     if( iCol==pTab->nCol ){
3668       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3669         iCol = pTab->iPKey;
3670         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3671       }else{
3672         pTab = 0;
3673         goto error_out;
3674       }
3675     }
3676   }
3677 
3678   /* The following block stores the meta information that will be returned
3679   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3680   ** and autoinc. At this point there are two possibilities:
3681   **
3682   **     1. The specified column name was rowid", "oid" or "_rowid_"
3683   **        and there is no explicitly declared IPK column.
3684   **
3685   **     2. The table is not a view and the column name identified an
3686   **        explicitly declared column. Copy meta information from *pCol.
3687   */
3688   if( pCol ){
3689     zDataType = sqlite3ColumnType(pCol,0);
3690     zCollSeq = pCol->zColl;
3691     notnull = pCol->notNull!=0;
3692     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3693     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3694   }else{
3695     zDataType = "INTEGER";
3696     primarykey = 1;
3697   }
3698   if( !zCollSeq ){
3699     zCollSeq = sqlite3StrBINARY;
3700   }
3701 
3702 error_out:
3703   sqlite3BtreeLeaveAll(db);
3704 
3705   /* Whether the function call succeeded or failed, set the output parameters
3706   ** to whatever their local counterparts contain. If an error did occur,
3707   ** this has the effect of zeroing all output parameters.
3708   */
3709   if( pzDataType ) *pzDataType = zDataType;
3710   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3711   if( pNotNull ) *pNotNull = notnull;
3712   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3713   if( pAutoinc ) *pAutoinc = autoinc;
3714 
3715   if( SQLITE_OK==rc && !pTab ){
3716     sqlite3DbFree(db, zErrMsg);
3717     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3718         zColumnName);
3719     rc = SQLITE_ERROR;
3720   }
3721   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3722   sqlite3DbFree(db, zErrMsg);
3723   rc = sqlite3ApiExit(db, rc);
3724   sqlite3_mutex_leave(db->mutex);
3725   return rc;
3726 }
3727 
3728 /*
3729 ** Sleep for a little while.  Return the amount of time slept.
3730 */
3731 int sqlite3_sleep(int ms){
3732   sqlite3_vfs *pVfs;
3733   int rc;
3734   pVfs = sqlite3_vfs_find(0);
3735   if( pVfs==0 ) return 0;
3736 
3737   /* This function works in milliseconds, but the underlying OsSleep()
3738   ** API uses microseconds. Hence the 1000's.
3739   */
3740   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3741   return rc;
3742 }
3743 
3744 /*
3745 ** Enable or disable the extended result codes.
3746 */
3747 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3748 #ifdef SQLITE_ENABLE_API_ARMOR
3749   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3750 #endif
3751   sqlite3_mutex_enter(db->mutex);
3752   db->errMask = onoff ? 0xffffffff : 0xff;
3753   sqlite3_mutex_leave(db->mutex);
3754   return SQLITE_OK;
3755 }
3756 
3757 /*
3758 ** Invoke the xFileControl method on a particular database.
3759 */
3760 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3761   int rc = SQLITE_ERROR;
3762   Btree *pBtree;
3763 
3764 #ifdef SQLITE_ENABLE_API_ARMOR
3765   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3766 #endif
3767   sqlite3_mutex_enter(db->mutex);
3768   pBtree = sqlite3DbNameToBtree(db, zDbName);
3769   if( pBtree ){
3770     Pager *pPager;
3771     sqlite3_file *fd;
3772     sqlite3BtreeEnter(pBtree);
3773     pPager = sqlite3BtreePager(pBtree);
3774     assert( pPager!=0 );
3775     fd = sqlite3PagerFile(pPager);
3776     assert( fd!=0 );
3777     if( op==SQLITE_FCNTL_FILE_POINTER ){
3778       *(sqlite3_file**)pArg = fd;
3779       rc = SQLITE_OK;
3780     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3781       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3782       rc = SQLITE_OK;
3783     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3784       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3785       rc = SQLITE_OK;
3786     }else if( op==SQLITE_FCNTL_DATA_VERSION ){
3787       *(unsigned int*)pArg = sqlite3PagerDataVersion(pPager);
3788       rc = SQLITE_OK;
3789     }else{
3790       rc = sqlite3OsFileControl(fd, op, pArg);
3791     }
3792     sqlite3BtreeLeave(pBtree);
3793   }
3794   sqlite3_mutex_leave(db->mutex);
3795   return rc;
3796 }
3797 
3798 /*
3799 ** Interface to the testing logic.
3800 */
3801 int sqlite3_test_control(int op, ...){
3802   int rc = 0;
3803 #ifdef SQLITE_UNTESTABLE
3804   UNUSED_PARAMETER(op);
3805 #else
3806   va_list ap;
3807   va_start(ap, op);
3808   switch( op ){
3809 
3810     /*
3811     ** Save the current state of the PRNG.
3812     */
3813     case SQLITE_TESTCTRL_PRNG_SAVE: {
3814       sqlite3PrngSaveState();
3815       break;
3816     }
3817 
3818     /*
3819     ** Restore the state of the PRNG to the last state saved using
3820     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3821     ** this verb acts like PRNG_RESET.
3822     */
3823     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3824       sqlite3PrngRestoreState();
3825       break;
3826     }
3827 
3828     /*  sqlite3_test_control(SQLITE_TESTCTRL_PRNG_SEED, int x, sqlite3 *db);
3829     **
3830     ** Control the seed for the pseudo-random number generator (PRNG) that
3831     ** is built into SQLite.  Cases:
3832     **
3833     **    x!=0 && db!=0       Seed the PRNG to the current value of the
3834     **                        schema cookie in the main database for db, or
3835     **                        x if the schema cookie is zero.  This case
3836     **                        is convenient to use with database fuzzers
3837     **                        as it allows the fuzzer some control over the
3838     **                        the PRNG seed.
3839     **
3840     **    x!=0 && db==0       Seed the PRNG to the value of x.
3841     **
3842     **    x==0 && db==0       Revert to default behavior of using the
3843     **                        xRandomness method on the primary VFS.
3844     **
3845     ** This test-control also resets the PRNG so that the new seed will
3846     ** be used for the next call to sqlite3_randomness().
3847     */
3848     case SQLITE_TESTCTRL_PRNG_SEED: {
3849       int x = va_arg(ap, int);
3850       int y;
3851       sqlite3 *db = va_arg(ap, sqlite3*);
3852       assert( db==0 || db->aDb[0].pSchema!=0 );
3853       if( db && (y = db->aDb[0].pSchema->schema_cookie)!=0 ){ x = y; }
3854       sqlite3Config.iPrngSeed = x;
3855       sqlite3_randomness(0,0);
3856       break;
3857     }
3858 
3859     /*
3860     **  sqlite3_test_control(BITVEC_TEST, size, program)
3861     **
3862     ** Run a test against a Bitvec object of size.  The program argument
3863     ** is an array of integers that defines the test.  Return -1 on a
3864     ** memory allocation error, 0 on success, or non-zero for an error.
3865     ** See the sqlite3BitvecBuiltinTest() for additional information.
3866     */
3867     case SQLITE_TESTCTRL_BITVEC_TEST: {
3868       int sz = va_arg(ap, int);
3869       int *aProg = va_arg(ap, int*);
3870       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3871       break;
3872     }
3873 
3874     /*
3875     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3876     **
3877     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3878     ** if xCallback is not NULL.
3879     **
3880     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3881     ** is called immediately after installing the new callback and the return
3882     ** value from sqlite3FaultSim(0) becomes the return from
3883     ** sqlite3_test_control().
3884     */
3885     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3886       /* MSVC is picky about pulling func ptrs from va lists.
3887       ** http://support.microsoft.com/kb/47961
3888       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3889       */
3890       typedef int(*TESTCALLBACKFUNC_t)(int);
3891       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3892       rc = sqlite3FaultSim(0);
3893       break;
3894     }
3895 
3896     /*
3897     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3898     **
3899     ** Register hooks to call to indicate which malloc() failures
3900     ** are benign.
3901     */
3902     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3903       typedef void (*void_function)(void);
3904       void_function xBenignBegin;
3905       void_function xBenignEnd;
3906       xBenignBegin = va_arg(ap, void_function);
3907       xBenignEnd = va_arg(ap, void_function);
3908       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3909       break;
3910     }
3911 
3912     /*
3913     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3914     **
3915     ** Set the PENDING byte to the value in the argument, if X>0.
3916     ** Make no changes if X==0.  Return the value of the pending byte
3917     ** as it existing before this routine was called.
3918     **
3919     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3920     ** an incompatible database file format.  Changing the PENDING byte
3921     ** while any database connection is open results in undefined and
3922     ** deleterious behavior.
3923     */
3924     case SQLITE_TESTCTRL_PENDING_BYTE: {
3925       rc = PENDING_BYTE;
3926 #ifndef SQLITE_OMIT_WSD
3927       {
3928         unsigned int newVal = va_arg(ap, unsigned int);
3929         if( newVal ) sqlite3PendingByte = newVal;
3930       }
3931 #endif
3932       break;
3933     }
3934 
3935     /*
3936     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3937     **
3938     ** This action provides a run-time test to see whether or not
3939     ** assert() was enabled at compile-time.  If X is true and assert()
3940     ** is enabled, then the return value is true.  If X is true and
3941     ** assert() is disabled, then the return value is zero.  If X is
3942     ** false and assert() is enabled, then the assertion fires and the
3943     ** process aborts.  If X is false and assert() is disabled, then the
3944     ** return value is zero.
3945     */
3946     case SQLITE_TESTCTRL_ASSERT: {
3947       volatile int x = 0;
3948       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3949       rc = x;
3950       break;
3951     }
3952 
3953 
3954     /*
3955     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3956     **
3957     ** This action provides a run-time test to see how the ALWAYS and
3958     ** NEVER macros were defined at compile-time.
3959     **
3960     ** The return value is ALWAYS(X) if X is true, or 0 if X is false.
3961     **
3962     ** The recommended test is X==2.  If the return value is 2, that means
3963     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3964     ** default setting.  If the return value is 1, then ALWAYS() is either
3965     ** hard-coded to true or else it asserts if its argument is false.
3966     ** The first behavior (hard-coded to true) is the case if
3967     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3968     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3969     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3970     **
3971     ** The run-time test procedure might look something like this:
3972     **
3973     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3974     **      // ALWAYS() and NEVER() are no-op pass-through macros
3975     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3976     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3977     **    }else{
3978     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3979     **    }
3980     */
3981     case SQLITE_TESTCTRL_ALWAYS: {
3982       int x = va_arg(ap,int);
3983       rc = x ? ALWAYS(x) : 0;
3984       break;
3985     }
3986 
3987     /*
3988     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3989     **
3990     ** The integer returned reveals the byte-order of the computer on which
3991     ** SQLite is running:
3992     **
3993     **       1     big-endian,    determined at run-time
3994     **      10     little-endian, determined at run-time
3995     **  432101     big-endian,    determined at compile-time
3996     **  123410     little-endian, determined at compile-time
3997     */
3998     case SQLITE_TESTCTRL_BYTEORDER: {
3999       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
4000       break;
4001     }
4002 
4003     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
4004     **
4005     ** Set the nReserve size to N for the main database on the database
4006     ** connection db.
4007     */
4008     case SQLITE_TESTCTRL_RESERVE: {
4009       sqlite3 *db = va_arg(ap, sqlite3*);
4010       int x = va_arg(ap,int);
4011       sqlite3_mutex_enter(db->mutex);
4012       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
4013       sqlite3_mutex_leave(db->mutex);
4014       break;
4015     }
4016 
4017     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
4018     **
4019     ** Enable or disable various optimizations for testing purposes.  The
4020     ** argument N is a bitmask of optimizations to be disabled.  For normal
4021     ** operation N should be 0.  The idea is that a test program (like the
4022     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
4023     ** with various optimizations disabled to verify that the same answer
4024     ** is obtained in every case.
4025     */
4026     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
4027       sqlite3 *db = va_arg(ap, sqlite3*);
4028       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
4029       break;
4030     }
4031 
4032     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
4033     **
4034     ** If parameter onoff is non-zero, subsequent calls to localtime()
4035     ** and its variants fail. If onoff is zero, undo this setting.
4036     */
4037     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
4038       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
4039       break;
4040     }
4041 
4042     /*   sqlite3_test_control(SQLITE_TESTCTRL_INTERNAL_FUNCS, int onoff);
4043     **
4044     ** If parameter onoff is non-zero, internal-use-only SQL functions
4045     ** are visible to ordinary SQL.  This is useful for testing but is
4046     ** unsafe because invalid parameters to those internal-use-only functions
4047     ** can result in crashes or segfaults.
4048     */
4049     case SQLITE_TESTCTRL_INTERNAL_FUNCTIONS: {
4050       sqlite3GlobalConfig.bInternalFunctions = va_arg(ap, int);
4051       break;
4052     }
4053 
4054     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
4055     **
4056     ** Set or clear a flag that indicates that the database file is always well-
4057     ** formed and never corrupt.  This flag is clear by default, indicating that
4058     ** database files might have arbitrary corruption.  Setting the flag during
4059     ** testing causes certain assert() statements in the code to be activated
4060     ** that demonstrat invariants on well-formed database files.
4061     */
4062     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
4063       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
4064       break;
4065     }
4066 
4067     /*   sqlite3_test_control(SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS, int);
4068     **
4069     ** Set or clear a flag that causes SQLite to verify that type, name,
4070     ** and tbl_name fields of the sqlite_master table.  This is normally
4071     ** on, but it is sometimes useful to turn it off for testing.
4072     */
4073     case SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS: {
4074       sqlite3GlobalConfig.bExtraSchemaChecks = va_arg(ap, int);
4075       break;
4076     }
4077 
4078     /* Set the threshold at which OP_Once counters reset back to zero.
4079     ** By default this is 0x7ffffffe (over 2 billion), but that value is
4080     ** too big to test in a reasonable amount of time, so this control is
4081     ** provided to set a small and easily reachable reset value.
4082     */
4083     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
4084       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
4085       break;
4086     }
4087 
4088     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
4089     **
4090     ** Set the VDBE coverage callback function to xCallback with context
4091     ** pointer ptr.
4092     */
4093     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
4094 #ifdef SQLITE_VDBE_COVERAGE
4095       typedef void (*branch_callback)(void*,unsigned int,
4096                                       unsigned char,unsigned char);
4097       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
4098       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
4099 #endif
4100       break;
4101     }
4102 
4103     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
4104     case SQLITE_TESTCTRL_SORTER_MMAP: {
4105       sqlite3 *db = va_arg(ap, sqlite3*);
4106       db->nMaxSorterMmap = va_arg(ap, int);
4107       break;
4108     }
4109 
4110     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
4111     **
4112     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
4113     ** not.
4114     */
4115     case SQLITE_TESTCTRL_ISINIT: {
4116       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
4117       break;
4118     }
4119 
4120     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
4121     **
4122     ** This test control is used to create imposter tables.  "db" is a pointer
4123     ** to the database connection.  dbName is the database name (ex: "main" or
4124     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
4125     ** or off.  "tnum" is the root page of the b-tree to which the imposter
4126     ** table should connect.
4127     **
4128     ** Enable imposter mode only when the schema has already been parsed.  Then
4129     ** run a single CREATE TABLE statement to construct the imposter table in
4130     ** the parsed schema.  Then turn imposter mode back off again.
4131     **
4132     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
4133     ** the schema to be reparsed the next time it is needed.  This has the
4134     ** effect of erasing all imposter tables.
4135     */
4136     case SQLITE_TESTCTRL_IMPOSTER: {
4137       sqlite3 *db = va_arg(ap, sqlite3*);
4138       sqlite3_mutex_enter(db->mutex);
4139       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
4140       db->init.busy = db->init.imposterTable = va_arg(ap,int);
4141       db->init.newTnum = va_arg(ap,int);
4142       if( db->init.busy==0 && db->init.newTnum>0 ){
4143         sqlite3ResetAllSchemasOfConnection(db);
4144       }
4145       sqlite3_mutex_leave(db->mutex);
4146       break;
4147     }
4148 
4149 #if defined(YYCOVERAGE)
4150     /*  sqlite3_test_control(SQLITE_TESTCTRL_PARSER_COVERAGE, FILE *out)
4151     **
4152     ** This test control (only available when SQLite is compiled with
4153     ** -DYYCOVERAGE) writes a report onto "out" that shows all
4154     ** state/lookahead combinations in the parser state machine
4155     ** which are never exercised.  If any state is missed, make the
4156     ** return code SQLITE_ERROR.
4157     */
4158     case SQLITE_TESTCTRL_PARSER_COVERAGE: {
4159       FILE *out = va_arg(ap, FILE*);
4160       if( sqlite3ParserCoverage(out) ) rc = SQLITE_ERROR;
4161       break;
4162     }
4163 #endif /* defined(YYCOVERAGE) */
4164 
4165     /*  sqlite3_test_control(SQLITE_TESTCTRL_RESULT_INTREAL, sqlite3_context*);
4166     **
4167     ** This test-control causes the most recent sqlite3_result_int64() value
4168     ** to be interpreted as a MEM_IntReal instead of as an MEM_Int.  Normally,
4169     ** MEM_IntReal values only arise during an INSERT operation of integer
4170     ** values into a REAL column, so they can be challenging to test.  This
4171     ** test-control enables us to write an intreal() SQL function that can
4172     ** inject an intreal() value at arbitrary places in an SQL statement,
4173     ** for testing purposes.
4174     */
4175     case SQLITE_TESTCTRL_RESULT_INTREAL: {
4176       sqlite3_context *pCtx = va_arg(ap, sqlite3_context*);
4177       sqlite3ResultIntReal(pCtx);
4178       break;
4179     }
4180   }
4181   va_end(ap);
4182 #endif /* SQLITE_UNTESTABLE */
4183   return rc;
4184 }
4185 
4186 /*
4187 ** This is a utility routine, useful to VFS implementations, that checks
4188 ** to see if a database file was a URI that contained a specific query
4189 ** parameter, and if so obtains the value of the query parameter.
4190 **
4191 ** The zFilename argument is the filename pointer passed into the xOpen()
4192 ** method of a VFS implementation.  The zParam argument is the name of the
4193 ** query parameter we seek.  This routine returns the value of the zParam
4194 ** parameter if it exists.  If the parameter does not exist, this routine
4195 ** returns a NULL pointer.
4196 */
4197 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
4198   if( zFilename==0 || zParam==0 ) return 0;
4199   zFilename += sqlite3Strlen30(zFilename) + 1;
4200   while( zFilename[0] ){
4201     int x = strcmp(zFilename, zParam);
4202     zFilename += sqlite3Strlen30(zFilename) + 1;
4203     if( x==0 ) return zFilename;
4204     zFilename += sqlite3Strlen30(zFilename) + 1;
4205   }
4206   return 0;
4207 }
4208 
4209 /*
4210 ** Return a boolean value for a query parameter.
4211 */
4212 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
4213   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4214   bDflt = bDflt!=0;
4215   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
4216 }
4217 
4218 /*
4219 ** Return a 64-bit integer value for a query parameter.
4220 */
4221 sqlite3_int64 sqlite3_uri_int64(
4222   const char *zFilename,    /* Filename as passed to xOpen */
4223   const char *zParam,       /* URI parameter sought */
4224   sqlite3_int64 bDflt       /* return if parameter is missing */
4225 ){
4226   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4227   sqlite3_int64 v;
4228   if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
4229     bDflt = v;
4230   }
4231   return bDflt;
4232 }
4233 
4234 /*
4235 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
4236 */
4237 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
4238   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
4239   return iDb<0 ? 0 : db->aDb[iDb].pBt;
4240 }
4241 
4242 /*
4243 ** Return the filename of the database associated with a database
4244 ** connection.
4245 */
4246 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
4247   Btree *pBt;
4248 #ifdef SQLITE_ENABLE_API_ARMOR
4249   if( !sqlite3SafetyCheckOk(db) ){
4250     (void)SQLITE_MISUSE_BKPT;
4251     return 0;
4252   }
4253 #endif
4254   pBt = sqlite3DbNameToBtree(db, zDbName);
4255   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
4256 }
4257 
4258 /*
4259 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
4260 ** no such database exists.
4261 */
4262 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
4263   Btree *pBt;
4264 #ifdef SQLITE_ENABLE_API_ARMOR
4265   if( !sqlite3SafetyCheckOk(db) ){
4266     (void)SQLITE_MISUSE_BKPT;
4267     return -1;
4268   }
4269 #endif
4270   pBt = sqlite3DbNameToBtree(db, zDbName);
4271   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
4272 }
4273 
4274 #ifdef SQLITE_ENABLE_SNAPSHOT
4275 /*
4276 ** Obtain a snapshot handle for the snapshot of database zDb currently
4277 ** being read by handle db.
4278 */
4279 int sqlite3_snapshot_get(
4280   sqlite3 *db,
4281   const char *zDb,
4282   sqlite3_snapshot **ppSnapshot
4283 ){
4284   int rc = SQLITE_ERROR;
4285 #ifndef SQLITE_OMIT_WAL
4286 
4287 #ifdef SQLITE_ENABLE_API_ARMOR
4288   if( !sqlite3SafetyCheckOk(db) ){
4289     return SQLITE_MISUSE_BKPT;
4290   }
4291 #endif
4292   sqlite3_mutex_enter(db->mutex);
4293 
4294   if( db->autoCommit==0 ){
4295     int iDb = sqlite3FindDbName(db, zDb);
4296     if( iDb==0 || iDb>1 ){
4297       Btree *pBt = db->aDb[iDb].pBt;
4298       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4299         rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4300         if( rc==SQLITE_OK ){
4301           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4302         }
4303       }
4304     }
4305   }
4306 
4307   sqlite3_mutex_leave(db->mutex);
4308 #endif   /* SQLITE_OMIT_WAL */
4309   return rc;
4310 }
4311 
4312 /*
4313 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4314 */
4315 int sqlite3_snapshot_open(
4316   sqlite3 *db,
4317   const char *zDb,
4318   sqlite3_snapshot *pSnapshot
4319 ){
4320   int rc = SQLITE_ERROR;
4321 #ifndef SQLITE_OMIT_WAL
4322 
4323 #ifdef SQLITE_ENABLE_API_ARMOR
4324   if( !sqlite3SafetyCheckOk(db) ){
4325     return SQLITE_MISUSE_BKPT;
4326   }
4327 #endif
4328   sqlite3_mutex_enter(db->mutex);
4329   if( db->autoCommit==0 ){
4330     int iDb;
4331     iDb = sqlite3FindDbName(db, zDb);
4332     if( iDb==0 || iDb>1 ){
4333       Btree *pBt = db->aDb[iDb].pBt;
4334       if( sqlite3BtreeIsInTrans(pBt)==0 ){
4335         Pager *pPager = sqlite3BtreePager(pBt);
4336         int bUnlock = 0;
4337         if( sqlite3BtreeIsInReadTrans(pBt) ){
4338           if( db->nVdbeActive==0 ){
4339             rc = sqlite3PagerSnapshotCheck(pPager, pSnapshot);
4340             if( rc==SQLITE_OK ){
4341               bUnlock = 1;
4342               rc = sqlite3BtreeCommit(pBt);
4343             }
4344           }
4345         }else{
4346           rc = SQLITE_OK;
4347         }
4348         if( rc==SQLITE_OK ){
4349           rc = sqlite3PagerSnapshotOpen(pPager, pSnapshot);
4350         }
4351         if( rc==SQLITE_OK ){
4352           rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4353           sqlite3PagerSnapshotOpen(pPager, 0);
4354         }
4355         if( bUnlock ){
4356           sqlite3PagerSnapshotUnlock(pPager);
4357         }
4358       }
4359     }
4360   }
4361 
4362   sqlite3_mutex_leave(db->mutex);
4363 #endif   /* SQLITE_OMIT_WAL */
4364   return rc;
4365 }
4366 
4367 /*
4368 ** Recover as many snapshots as possible from the wal file associated with
4369 ** schema zDb of database db.
4370 */
4371 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4372   int rc = SQLITE_ERROR;
4373   int iDb;
4374 #ifndef SQLITE_OMIT_WAL
4375 
4376 #ifdef SQLITE_ENABLE_API_ARMOR
4377   if( !sqlite3SafetyCheckOk(db) ){
4378     return SQLITE_MISUSE_BKPT;
4379   }
4380 #endif
4381 
4382   sqlite3_mutex_enter(db->mutex);
4383   iDb = sqlite3FindDbName(db, zDb);
4384   if( iDb==0 || iDb>1 ){
4385     Btree *pBt = db->aDb[iDb].pBt;
4386     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4387       rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4388       if( rc==SQLITE_OK ){
4389         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4390         sqlite3BtreeCommit(pBt);
4391       }
4392     }
4393   }
4394   sqlite3_mutex_leave(db->mutex);
4395 #endif   /* SQLITE_OMIT_WAL */
4396   return rc;
4397 }
4398 
4399 /*
4400 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4401 */
4402 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4403   sqlite3_free(pSnapshot);
4404 }
4405 #endif /* SQLITE_ENABLE_SNAPSHOT */
4406 
4407 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4408 /*
4409 ** Given the name of a compile-time option, return true if that option
4410 ** was used and false if not.
4411 **
4412 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4413 ** is not required for a match.
4414 */
4415 int sqlite3_compileoption_used(const char *zOptName){
4416   int i, n;
4417   int nOpt;
4418   const char **azCompileOpt;
4419 
4420 #if SQLITE_ENABLE_API_ARMOR
4421   if( zOptName==0 ){
4422     (void)SQLITE_MISUSE_BKPT;
4423     return 0;
4424   }
4425 #endif
4426 
4427   azCompileOpt = sqlite3CompileOptions(&nOpt);
4428 
4429   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4430   n = sqlite3Strlen30(zOptName);
4431 
4432   /* Since nOpt is normally in single digits, a linear search is
4433   ** adequate. No need for a binary search. */
4434   for(i=0; i<nOpt; i++){
4435     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4436      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4437     ){
4438       return 1;
4439     }
4440   }
4441   return 0;
4442 }
4443 
4444 /*
4445 ** Return the N-th compile-time option string.  If N is out of range,
4446 ** return a NULL pointer.
4447 */
4448 const char *sqlite3_compileoption_get(int N){
4449   int nOpt;
4450   const char **azCompileOpt;
4451   azCompileOpt = sqlite3CompileOptions(&nOpt);
4452   if( N>=0 && N<nOpt ){
4453     return azCompileOpt[N];
4454   }
4455   return 0;
4456 }
4457 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4458