xref: /sqlite-3.40.0/src/main.c (revision e6f98bcf)
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 #ifdef SQLITE_ENABLE_ICU
26 # include "sqliteicu.h"
27 #endif
28 #ifdef SQLITE_ENABLE_JSON1
29 int sqlite3Json1Init(sqlite3*);
30 #endif
31 #ifdef SQLITE_ENABLE_FTS5
32 int sqlite3Fts5Init(sqlite3*);
33 #endif
34 
35 #ifndef SQLITE_AMALGAMATION
36 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
37 ** contains the text of SQLITE_VERSION macro.
38 */
39 const char sqlite3_version[] = SQLITE_VERSION;
40 #endif
41 
42 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
43 ** a pointer to the to the sqlite3_version[] string constant.
44 */
45 const char *sqlite3_libversion(void){ return sqlite3_version; }
46 
47 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
48 ** pointer to a string constant whose value is the same as the
49 ** SQLITE_SOURCE_ID C preprocessor macro.
50 */
51 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
52 
53 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
54 ** returns an integer equal to SQLITE_VERSION_NUMBER.
55 */
56 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
57 
58 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
59 ** zero if and only if SQLite was compiled with mutexing code omitted due to
60 ** the SQLITE_THREADSAFE compile-time option being set to 0.
61 */
62 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
63 
64 /*
65 ** When compiling the test fixture or with debugging enabled (on Win32),
66 ** this variable being set to non-zero will cause OSTRACE macros to emit
67 ** extra diagnostic information.
68 */
69 #ifdef SQLITE_HAVE_OS_TRACE
70 # ifndef SQLITE_DEBUG_OS_TRACE
71 #   define SQLITE_DEBUG_OS_TRACE 0
72 # endif
73   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
74 #endif
75 
76 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
77 /*
78 ** If the following function pointer is not NULL and if
79 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
80 ** I/O active are written using this function.  These messages
81 ** are intended for debugging activity only.
82 */
83 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
84 #endif
85 
86 /*
87 ** If the following global variable points to a string which is the
88 ** name of a directory, then that directory will be used to store
89 ** temporary files.
90 **
91 ** See also the "PRAGMA temp_store_directory" SQL command.
92 */
93 char *sqlite3_temp_directory = 0;
94 
95 /*
96 ** If the following global variable points to a string which is the
97 ** name of a directory, then that directory will be used to store
98 ** all database files specified with a relative pathname.
99 **
100 ** See also the "PRAGMA data_store_directory" SQL command.
101 */
102 char *sqlite3_data_directory = 0;
103 
104 /*
105 ** Initialize SQLite.
106 **
107 ** This routine must be called to initialize the memory allocation,
108 ** VFS, and mutex subsystems prior to doing any serious work with
109 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
110 ** this routine will be called automatically by key routines such as
111 ** sqlite3_open().
112 **
113 ** This routine is a no-op except on its very first call for the process,
114 ** or for the first call after a call to sqlite3_shutdown.
115 **
116 ** The first thread to call this routine runs the initialization to
117 ** completion.  If subsequent threads call this routine before the first
118 ** thread has finished the initialization process, then the subsequent
119 ** threads must block until the first thread finishes with the initialization.
120 **
121 ** The first thread might call this routine recursively.  Recursive
122 ** calls to this routine should not block, of course.  Otherwise the
123 ** initialization process would never complete.
124 **
125 ** Let X be the first thread to enter this routine.  Let Y be some other
126 ** thread.  Then while the initial invocation of this routine by X is
127 ** incomplete, it is required that:
128 **
129 **    *  Calls to this routine from Y must block until the outer-most
130 **       call by X completes.
131 **
132 **    *  Recursive calls to this routine from thread X return immediately
133 **       without blocking.
134 */
135 int sqlite3_initialize(void){
136   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
137   int rc;                                      /* Result code */
138 #ifdef SQLITE_EXTRA_INIT
139   int bRunExtraInit = 0;                       /* Extra initialization needed */
140 #endif
141 
142 #ifdef SQLITE_OMIT_WSD
143   rc = sqlite3_wsd_init(4096, 24);
144   if( rc!=SQLITE_OK ){
145     return rc;
146   }
147 #endif
148 
149   /* If the following assert() fails on some obscure processor/compiler
150   ** combination, the work-around is to set the correct pointer
151   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
152   assert( SQLITE_PTRSIZE==sizeof(char*) );
153 
154   /* If SQLite is already completely initialized, then this call
155   ** to sqlite3_initialize() should be a no-op.  But the initialization
156   ** must be complete.  So isInit must not be set until the very end
157   ** of this routine.
158   */
159   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
160 
161   /* Make sure the mutex subsystem is initialized.  If unable to
162   ** initialize the mutex subsystem, return early with the error.
163   ** If the system is so sick that we are unable to allocate a mutex,
164   ** there is not much SQLite is going to be able to do.
165   **
166   ** The mutex subsystem must take care of serializing its own
167   ** initialization.
168   */
169   rc = sqlite3MutexInit();
170   if( rc ) return rc;
171 
172   /* Initialize the malloc() system and the recursive pInitMutex mutex.
173   ** This operation is protected by the STATIC_MASTER mutex.  Note that
174   ** MutexAlloc() is called for a static mutex prior to initializing the
175   ** malloc subsystem - this implies that the allocation of a static
176   ** mutex must not require support from the malloc subsystem.
177   */
178   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
179   sqlite3_mutex_enter(pMaster);
180   sqlite3GlobalConfig.isMutexInit = 1;
181   if( !sqlite3GlobalConfig.isMallocInit ){
182     rc = sqlite3MallocInit();
183   }
184   if( rc==SQLITE_OK ){
185     sqlite3GlobalConfig.isMallocInit = 1;
186     if( !sqlite3GlobalConfig.pInitMutex ){
187       sqlite3GlobalConfig.pInitMutex =
188            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
189       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
190         rc = SQLITE_NOMEM_BKPT;
191       }
192     }
193   }
194   if( rc==SQLITE_OK ){
195     sqlite3GlobalConfig.nRefInitMutex++;
196   }
197   sqlite3_mutex_leave(pMaster);
198 
199   /* If rc is not SQLITE_OK at this point, then either the malloc
200   ** subsystem could not be initialized or the system failed to allocate
201   ** the pInitMutex mutex. Return an error in either case.  */
202   if( rc!=SQLITE_OK ){
203     return rc;
204   }
205 
206   /* Do the rest of the initialization under the recursive mutex so
207   ** that we will be able to handle recursive calls into
208   ** sqlite3_initialize().  The recursive calls normally come through
209   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
210   ** recursive calls might also be possible.
211   **
212   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
213   ** to the xInit method, so the xInit method need not be threadsafe.
214   **
215   ** The following mutex is what serializes access to the appdef pcache xInit
216   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
217   ** call to sqlite3PcacheInitialize().
218   */
219   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
220   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
221     sqlite3GlobalConfig.inProgress = 1;
222 #ifdef SQLITE_ENABLE_SQLLOG
223     {
224       extern void sqlite3_init_sqllog(void);
225       sqlite3_init_sqllog();
226     }
227 #endif
228     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
229     sqlite3RegisterBuiltinFunctions();
230     if( sqlite3GlobalConfig.isPCacheInit==0 ){
231       rc = sqlite3PcacheInitialize();
232     }
233     if( rc==SQLITE_OK ){
234       sqlite3GlobalConfig.isPCacheInit = 1;
235       rc = sqlite3OsInit();
236     }
237     if( rc==SQLITE_OK ){
238       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
239           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
240       sqlite3GlobalConfig.isInit = 1;
241 #ifdef SQLITE_EXTRA_INIT
242       bRunExtraInit = 1;
243 #endif
244     }
245     sqlite3GlobalConfig.inProgress = 0;
246   }
247   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
248 
249   /* Go back under the static mutex and clean up the recursive
250   ** mutex to prevent a resource leak.
251   */
252   sqlite3_mutex_enter(pMaster);
253   sqlite3GlobalConfig.nRefInitMutex--;
254   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
255     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
256     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
257     sqlite3GlobalConfig.pInitMutex = 0;
258   }
259   sqlite3_mutex_leave(pMaster);
260 
261   /* The following is just a sanity check to make sure SQLite has
262   ** been compiled correctly.  It is important to run this code, but
263   ** we don't want to run it too often and soak up CPU cycles for no
264   ** reason.  So we run it once during initialization.
265   */
266 #ifndef NDEBUG
267 #ifndef SQLITE_OMIT_FLOATING_POINT
268   /* This section of code's only "output" is via assert() statements. */
269   if ( rc==SQLITE_OK ){
270     u64 x = (((u64)1)<<63)-1;
271     double y;
272     assert(sizeof(x)==8);
273     assert(sizeof(x)==sizeof(y));
274     memcpy(&y, &x, 8);
275     assert( sqlite3IsNaN(y) );
276   }
277 #endif
278 #endif
279 
280   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
281   ** compile-time option.
282   */
283 #ifdef SQLITE_EXTRA_INIT
284   if( bRunExtraInit ){
285     int SQLITE_EXTRA_INIT(const char*);
286     rc = SQLITE_EXTRA_INIT(0);
287   }
288 #endif
289 
290   return rc;
291 }
292 
293 /*
294 ** Undo the effects of sqlite3_initialize().  Must not be called while
295 ** there are outstanding database connections or memory allocations or
296 ** while any part of SQLite is otherwise in use in any thread.  This
297 ** routine is not threadsafe.  But it is safe to invoke this routine
298 ** on when SQLite is already shut down.  If SQLite is already shut down
299 ** when this routine is invoked, then this routine is a harmless no-op.
300 */
301 int sqlite3_shutdown(void){
302 #ifdef SQLITE_OMIT_WSD
303   int rc = sqlite3_wsd_init(4096, 24);
304   if( rc!=SQLITE_OK ){
305     return rc;
306   }
307 #endif
308 
309   if( sqlite3GlobalConfig.isInit ){
310 #ifdef SQLITE_EXTRA_SHUTDOWN
311     void SQLITE_EXTRA_SHUTDOWN(void);
312     SQLITE_EXTRA_SHUTDOWN();
313 #endif
314     sqlite3_os_end();
315     sqlite3_reset_auto_extension();
316     sqlite3GlobalConfig.isInit = 0;
317   }
318   if( sqlite3GlobalConfig.isPCacheInit ){
319     sqlite3PcacheShutdown();
320     sqlite3GlobalConfig.isPCacheInit = 0;
321   }
322   if( sqlite3GlobalConfig.isMallocInit ){
323     sqlite3MallocEnd();
324     sqlite3GlobalConfig.isMallocInit = 0;
325 
326 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
327     /* The heap subsystem has now been shutdown and these values are supposed
328     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
329     ** which would rely on that heap subsystem; therefore, make sure these
330     ** values cannot refer to heap memory that was just invalidated when the
331     ** heap subsystem was shutdown.  This is only done if the current call to
332     ** this function resulted in the heap subsystem actually being shutdown.
333     */
334     sqlite3_data_directory = 0;
335     sqlite3_temp_directory = 0;
336 #endif
337   }
338   if( sqlite3GlobalConfig.isMutexInit ){
339     sqlite3MutexEnd();
340     sqlite3GlobalConfig.isMutexInit = 0;
341   }
342 
343   return SQLITE_OK;
344 }
345 
346 /*
347 ** This API allows applications to modify the global configuration of
348 ** the SQLite library at run-time.
349 **
350 ** This routine should only be called when there are no outstanding
351 ** database connections or memory allocations.  This routine is not
352 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
353 ** behavior.
354 */
355 int sqlite3_config(int op, ...){
356   va_list ap;
357   int rc = SQLITE_OK;
358 
359   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
360   ** the SQLite library is in use. */
361   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
362 
363   va_start(ap, op);
364   switch( op ){
365 
366     /* Mutex configuration options are only available in a threadsafe
367     ** compile.
368     */
369 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
370     case SQLITE_CONFIG_SINGLETHREAD: {
371       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
372       ** Single-thread. */
373       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
374       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
375       break;
376     }
377 #endif
378 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
379     case SQLITE_CONFIG_MULTITHREAD: {
380       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
381       ** Multi-thread. */
382       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
383       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
384       break;
385     }
386 #endif
387 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
388     case SQLITE_CONFIG_SERIALIZED: {
389       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
390       ** Serialized. */
391       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
392       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
393       break;
394     }
395 #endif
396 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
397     case SQLITE_CONFIG_MUTEX: {
398       /* Specify an alternative mutex implementation */
399       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
400       break;
401     }
402 #endif
403 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
404     case SQLITE_CONFIG_GETMUTEX: {
405       /* Retrieve the current mutex implementation */
406       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
407       break;
408     }
409 #endif
410 
411     case SQLITE_CONFIG_MALLOC: {
412       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
413       ** single argument which is a pointer to an instance of the
414       ** sqlite3_mem_methods structure. The argument specifies alternative
415       ** low-level memory allocation routines to be used in place of the memory
416       ** allocation routines built into SQLite. */
417       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
418       break;
419     }
420     case SQLITE_CONFIG_GETMALLOC: {
421       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
422       ** single argument which is a pointer to an instance of the
423       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
424       ** filled with the currently defined memory allocation routines. */
425       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
426       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
427       break;
428     }
429     case SQLITE_CONFIG_MEMSTATUS: {
430       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
431       ** single argument of type int, interpreted as a boolean, which enables
432       ** or disables the collection of memory allocation statistics. */
433       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
434       break;
435     }
436     case SQLITE_CONFIG_SCRATCH: {
437       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
438       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
439       ** which the scratch allocations will be drawn, the size of each scratch
440       ** allocation (sz), and the maximum number of scratch allocations (N). */
441       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
442       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
443       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
444       break;
445     }
446     case SQLITE_CONFIG_PAGECACHE: {
447       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
448       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
449       ** the size of each page cache line (sz), and the number of cache lines
450       ** (N). */
451       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
452       sqlite3GlobalConfig.szPage = va_arg(ap, int);
453       sqlite3GlobalConfig.nPage = va_arg(ap, int);
454       break;
455     }
456     case SQLITE_CONFIG_PCACHE_HDRSZ: {
457       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
458       ** a single parameter which is a pointer to an integer and writes into
459       ** that integer the number of extra bytes per page required for each page
460       ** in SQLITE_CONFIG_PAGECACHE. */
461       *va_arg(ap, int*) =
462           sqlite3HeaderSizeBtree() +
463           sqlite3HeaderSizePcache() +
464           sqlite3HeaderSizePcache1();
465       break;
466     }
467 
468     case SQLITE_CONFIG_PCACHE: {
469       /* no-op */
470       break;
471     }
472     case SQLITE_CONFIG_GETPCACHE: {
473       /* now an error */
474       rc = SQLITE_ERROR;
475       break;
476     }
477 
478     case SQLITE_CONFIG_PCACHE2: {
479       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
480       ** single argument which is a pointer to an sqlite3_pcache_methods2
481       ** object. This object specifies the interface to a custom page cache
482       ** implementation. */
483       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
484       break;
485     }
486     case SQLITE_CONFIG_GETPCACHE2: {
487       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
488       ** single argument which is a pointer to an sqlite3_pcache_methods2
489       ** object. SQLite copies of the current page cache implementation into
490       ** that object. */
491       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
492         sqlite3PCacheSetDefault();
493       }
494       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
495       break;
496     }
497 
498 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
499 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
500 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
501 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
502     case SQLITE_CONFIG_HEAP: {
503       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
504       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
505       ** number of bytes in the memory buffer, and the minimum allocation size.
506       */
507       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
508       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
509       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
510 
511       if( sqlite3GlobalConfig.mnReq<1 ){
512         sqlite3GlobalConfig.mnReq = 1;
513       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
514         /* cap min request size at 2^12 */
515         sqlite3GlobalConfig.mnReq = (1<<12);
516       }
517 
518       if( sqlite3GlobalConfig.pHeap==0 ){
519         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
520         ** is NULL, then SQLite reverts to using its default memory allocator
521         ** (the system malloc() implementation), undoing any prior invocation of
522         ** SQLITE_CONFIG_MALLOC.
523         **
524         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
525         ** revert to its default implementation when sqlite3_initialize() is run
526         */
527         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
528       }else{
529         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
530         ** alternative memory allocator is engaged to handle all of SQLites
531         ** memory allocation needs. */
532 #ifdef SQLITE_ENABLE_MEMSYS3
533         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
534 #endif
535 #ifdef SQLITE_ENABLE_MEMSYS5
536         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
537 #endif
538       }
539       break;
540     }
541 #endif
542 
543     case SQLITE_CONFIG_LOOKASIDE: {
544       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
545       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
546       break;
547     }
548 
549     /* Record a pointer to the logger function and its first argument.
550     ** The default is NULL.  Logging is disabled if the function pointer is
551     ** NULL.
552     */
553     case SQLITE_CONFIG_LOG: {
554       /* MSVC is picky about pulling func ptrs from va lists.
555       ** http://support.microsoft.com/kb/47961
556       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
557       */
558       typedef void(*LOGFUNC_t)(void*,int,const char*);
559       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
560       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
561       break;
562     }
563 
564     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
565     ** can be changed at start-time using the
566     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
567     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
568     */
569     case SQLITE_CONFIG_URI: {
570       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
571       ** argument of type int. If non-zero, then URI handling is globally
572       ** enabled. If the parameter is zero, then URI handling is globally
573       ** disabled. */
574       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
575       break;
576     }
577 
578     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
579       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
580       ** option takes a single integer argument which is interpreted as a
581       ** boolean in order to enable or disable the use of covering indices for
582       ** full table scans in the query optimizer. */
583       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
584       break;
585     }
586 
587 #ifdef SQLITE_ENABLE_SQLLOG
588     case SQLITE_CONFIG_SQLLOG: {
589       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
590       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
591       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
592       break;
593     }
594 #endif
595 
596     case SQLITE_CONFIG_MMAP_SIZE: {
597       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
598       ** integer (sqlite3_int64) values that are the default mmap size limit
599       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
600       ** mmap size limit. */
601       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
602       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
603       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
604       ** negative, then that argument is changed to its compile-time default.
605       **
606       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
607       ** silently truncated if necessary so that it does not exceed the
608       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
609       ** compile-time option.
610       */
611       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
612         mxMmap = SQLITE_MAX_MMAP_SIZE;
613       }
614       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
615       if( szMmap>mxMmap) szMmap = mxMmap;
616       sqlite3GlobalConfig.mxMmap = mxMmap;
617       sqlite3GlobalConfig.szMmap = szMmap;
618       break;
619     }
620 
621 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
622     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
623       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
624       ** unsigned integer value that specifies the maximum size of the created
625       ** heap. */
626       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
627       break;
628     }
629 #endif
630 
631     case SQLITE_CONFIG_PMASZ: {
632       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
633       break;
634     }
635 
636     case SQLITE_CONFIG_STMTJRNL_SPILL: {
637       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
638       break;
639     }
640 
641     default: {
642       rc = SQLITE_ERROR;
643       break;
644     }
645   }
646   va_end(ap);
647   return rc;
648 }
649 
650 /*
651 ** Set up the lookaside buffers for a database connection.
652 ** Return SQLITE_OK on success.
653 ** If lookaside is already active, return SQLITE_BUSY.
654 **
655 ** The sz parameter is the number of bytes in each lookaside slot.
656 ** The cnt parameter is the number of slots.  If pStart is NULL the
657 ** space for the lookaside memory is obtained from sqlite3_malloc().
658 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
659 ** the lookaside memory.
660 */
661 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
662 #ifndef SQLITE_OMIT_LOOKASIDE
663   void *pStart;
664   if( db->lookaside.nOut ){
665     return SQLITE_BUSY;
666   }
667   /* Free any existing lookaside buffer for this handle before
668   ** allocating a new one so we don't have to have space for
669   ** both at the same time.
670   */
671   if( db->lookaside.bMalloced ){
672     sqlite3_free(db->lookaside.pStart);
673   }
674   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
675   ** than a pointer to be useful.
676   */
677   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
678   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
679   if( cnt<0 ) cnt = 0;
680   if( sz==0 || cnt==0 ){
681     sz = 0;
682     pStart = 0;
683   }else if( pBuf==0 ){
684     sqlite3BeginBenignMalloc();
685     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
686     sqlite3EndBenignMalloc();
687     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
688   }else{
689     pStart = pBuf;
690   }
691   db->lookaside.pStart = pStart;
692   db->lookaside.pFree = 0;
693   db->lookaside.sz = (u16)sz;
694   if( pStart ){
695     int i;
696     LookasideSlot *p;
697     assert( sz > (int)sizeof(LookasideSlot*) );
698     p = (LookasideSlot*)pStart;
699     for(i=cnt-1; i>=0; i--){
700       p->pNext = db->lookaside.pFree;
701       db->lookaside.pFree = p;
702       p = (LookasideSlot*)&((u8*)p)[sz];
703     }
704     db->lookaside.pEnd = p;
705     db->lookaside.bDisable = 0;
706     db->lookaside.bMalloced = pBuf==0 ?1:0;
707   }else{
708     db->lookaside.pStart = db;
709     db->lookaside.pEnd = db;
710     db->lookaside.bDisable = 1;
711     db->lookaside.bMalloced = 0;
712   }
713 #endif /* SQLITE_OMIT_LOOKASIDE */
714   return SQLITE_OK;
715 }
716 
717 /*
718 ** Return the mutex associated with a database connection.
719 */
720 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
721 #ifdef SQLITE_ENABLE_API_ARMOR
722   if( !sqlite3SafetyCheckOk(db) ){
723     (void)SQLITE_MISUSE_BKPT;
724     return 0;
725   }
726 #endif
727   return db->mutex;
728 }
729 
730 /*
731 ** Free up as much memory as we can from the given database
732 ** connection.
733 */
734 int sqlite3_db_release_memory(sqlite3 *db){
735   int i;
736 
737 #ifdef SQLITE_ENABLE_API_ARMOR
738   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
739 #endif
740   sqlite3_mutex_enter(db->mutex);
741   sqlite3BtreeEnterAll(db);
742   for(i=0; i<db->nDb; i++){
743     Btree *pBt = db->aDb[i].pBt;
744     if( pBt ){
745       Pager *pPager = sqlite3BtreePager(pBt);
746       sqlite3PagerShrink(pPager);
747     }
748   }
749   sqlite3BtreeLeaveAll(db);
750   sqlite3_mutex_leave(db->mutex);
751   return SQLITE_OK;
752 }
753 
754 /*
755 ** Flush any dirty pages in the pager-cache for any attached database
756 ** to disk.
757 */
758 int sqlite3_db_cacheflush(sqlite3 *db){
759   int i;
760   int rc = SQLITE_OK;
761   int bSeenBusy = 0;
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; rc==SQLITE_OK && i<db->nDb; i++){
769     Btree *pBt = db->aDb[i].pBt;
770     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
771       Pager *pPager = sqlite3BtreePager(pBt);
772       rc = sqlite3PagerFlush(pPager);
773       if( rc==SQLITE_BUSY ){
774         bSeenBusy = 1;
775         rc = SQLITE_OK;
776       }
777     }
778   }
779   sqlite3BtreeLeaveAll(db);
780   sqlite3_mutex_leave(db->mutex);
781   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
782 }
783 
784 /*
785 ** Configuration settings for an individual database connection
786 */
787 int sqlite3_db_config(sqlite3 *db, int op, ...){
788   va_list ap;
789   int rc;
790   va_start(ap, op);
791   switch( op ){
792     case SQLITE_DBCONFIG_MAINDBNAME: {
793       db->aDb[0].zDbSName = va_arg(ap,char*);
794       rc = SQLITE_OK;
795       break;
796     }
797     case SQLITE_DBCONFIG_LOOKASIDE: {
798       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
799       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
800       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
801       rc = setupLookaside(db, pBuf, sz, cnt);
802       break;
803     }
804     default: {
805       static const struct {
806         int op;      /* The opcode */
807         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
808       } aFlagOp[] = {
809         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
810         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
811         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
812         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
813         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
814       };
815       unsigned int i;
816       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
817       for(i=0; i<ArraySize(aFlagOp); i++){
818         if( aFlagOp[i].op==op ){
819           int onoff = va_arg(ap, int);
820           int *pRes = va_arg(ap, int*);
821           int oldFlags = db->flags;
822           if( onoff>0 ){
823             db->flags |= aFlagOp[i].mask;
824           }else if( onoff==0 ){
825             db->flags &= ~aFlagOp[i].mask;
826           }
827           if( oldFlags!=db->flags ){
828             sqlite3ExpirePreparedStatements(db);
829           }
830           if( pRes ){
831             *pRes = (db->flags & aFlagOp[i].mask)!=0;
832           }
833           rc = SQLITE_OK;
834           break;
835         }
836       }
837       break;
838     }
839   }
840   va_end(ap);
841   return rc;
842 }
843 
844 
845 /*
846 ** Return true if the buffer z[0..n-1] contains all spaces.
847 */
848 static int allSpaces(const char *z, int n){
849   while( n>0 && z[n-1]==' ' ){ n--; }
850   return n==0;
851 }
852 
853 /*
854 ** This is the default collating function named "BINARY" which is always
855 ** available.
856 **
857 ** If the padFlag argument is not NULL then space padding at the end
858 ** of strings is ignored.  This implements the RTRIM collation.
859 */
860 static int binCollFunc(
861   void *padFlag,
862   int nKey1, const void *pKey1,
863   int nKey2, const void *pKey2
864 ){
865   int rc, n;
866   n = nKey1<nKey2 ? nKey1 : nKey2;
867   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
868   ** strings byte by byte using the memcmp() function from the standard C
869   ** library. */
870   assert( pKey1 && pKey2 );
871   rc = memcmp(pKey1, pKey2, n);
872   if( rc==0 ){
873     if( padFlag
874      && allSpaces(((char*)pKey1)+n, nKey1-n)
875      && allSpaces(((char*)pKey2)+n, nKey2-n)
876     ){
877       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
878       ** spaces at the end of either string do not change the result. In other
879       ** words, strings will compare equal to one another as long as they
880       ** differ only in the number of spaces at the end.
881       */
882     }else{
883       rc = nKey1 - nKey2;
884     }
885   }
886   return rc;
887 }
888 
889 /*
890 ** Another built-in collating sequence: NOCASE.
891 **
892 ** This collating sequence is intended to be used for "case independent
893 ** comparison". SQLite's knowledge of upper and lower case equivalents
894 ** extends only to the 26 characters used in the English language.
895 **
896 ** At the moment there is only a UTF-8 implementation.
897 */
898 static int nocaseCollatingFunc(
899   void *NotUsed,
900   int nKey1, const void *pKey1,
901   int nKey2, const void *pKey2
902 ){
903   int r = sqlite3StrNICmp(
904       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
905   UNUSED_PARAMETER(NotUsed);
906   if( 0==r ){
907     r = nKey1-nKey2;
908   }
909   return r;
910 }
911 
912 /*
913 ** Return the ROWID of the most recent insert
914 */
915 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
916 #ifdef SQLITE_ENABLE_API_ARMOR
917   if( !sqlite3SafetyCheckOk(db) ){
918     (void)SQLITE_MISUSE_BKPT;
919     return 0;
920   }
921 #endif
922   return db->lastRowid;
923 }
924 
925 /*
926 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
927 */
928 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
929 #ifdef SQLITE_ENABLE_API_ARMOR
930   if( !sqlite3SafetyCheckOk(db) ){
931     (void)SQLITE_MISUSE_BKPT;
932     return;
933   }
934 #endif
935   sqlite3_mutex_enter(db->mutex);
936   db->lastRowid = iRowid;
937   sqlite3_mutex_leave(db->mutex);
938 }
939 
940 /*
941 ** Return the number of changes in the most recent call to sqlite3_exec().
942 */
943 int sqlite3_changes(sqlite3 *db){
944 #ifdef SQLITE_ENABLE_API_ARMOR
945   if( !sqlite3SafetyCheckOk(db) ){
946     (void)SQLITE_MISUSE_BKPT;
947     return 0;
948   }
949 #endif
950   return db->nChange;
951 }
952 
953 /*
954 ** Return the number of changes since the database handle was opened.
955 */
956 int sqlite3_total_changes(sqlite3 *db){
957 #ifdef SQLITE_ENABLE_API_ARMOR
958   if( !sqlite3SafetyCheckOk(db) ){
959     (void)SQLITE_MISUSE_BKPT;
960     return 0;
961   }
962 #endif
963   return db->nTotalChange;
964 }
965 
966 /*
967 ** Close all open savepoints. This function only manipulates fields of the
968 ** database handle object, it does not close any savepoints that may be open
969 ** at the b-tree/pager level.
970 */
971 void sqlite3CloseSavepoints(sqlite3 *db){
972   while( db->pSavepoint ){
973     Savepoint *pTmp = db->pSavepoint;
974     db->pSavepoint = pTmp->pNext;
975     sqlite3DbFree(db, pTmp);
976   }
977   db->nSavepoint = 0;
978   db->nStatement = 0;
979   db->isTransactionSavepoint = 0;
980 }
981 
982 /*
983 ** Invoke the destructor function associated with FuncDef p, if any. Except,
984 ** if this is not the last copy of the function, do not invoke it. Multiple
985 ** copies of a single function are created when create_function() is called
986 ** with SQLITE_ANY as the encoding.
987 */
988 static void functionDestroy(sqlite3 *db, FuncDef *p){
989   FuncDestructor *pDestructor = p->u.pDestructor;
990   if( pDestructor ){
991     pDestructor->nRef--;
992     if( pDestructor->nRef==0 ){
993       pDestructor->xDestroy(pDestructor->pUserData);
994       sqlite3DbFree(db, pDestructor);
995     }
996   }
997 }
998 
999 /*
1000 ** Disconnect all sqlite3_vtab objects that belong to database connection
1001 ** db. This is called when db is being closed.
1002 */
1003 static void disconnectAllVtab(sqlite3 *db){
1004 #ifndef SQLITE_OMIT_VIRTUALTABLE
1005   int i;
1006   HashElem *p;
1007   sqlite3BtreeEnterAll(db);
1008   for(i=0; i<db->nDb; i++){
1009     Schema *pSchema = db->aDb[i].pSchema;
1010     if( db->aDb[i].pSchema ){
1011       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1012         Table *pTab = (Table *)sqliteHashData(p);
1013         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1014       }
1015     }
1016   }
1017   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1018     Module *pMod = (Module *)sqliteHashData(p);
1019     if( pMod->pEpoTab ){
1020       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1021     }
1022   }
1023   sqlite3VtabUnlockList(db);
1024   sqlite3BtreeLeaveAll(db);
1025 #else
1026   UNUSED_PARAMETER(db);
1027 #endif
1028 }
1029 
1030 /*
1031 ** Return TRUE if database connection db has unfinalized prepared
1032 ** statements or unfinished sqlite3_backup objects.
1033 */
1034 static int connectionIsBusy(sqlite3 *db){
1035   int j;
1036   assert( sqlite3_mutex_held(db->mutex) );
1037   if( db->pVdbe ) return 1;
1038   for(j=0; j<db->nDb; j++){
1039     Btree *pBt = db->aDb[j].pBt;
1040     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1041   }
1042   return 0;
1043 }
1044 
1045 /*
1046 ** Close an existing SQLite database
1047 */
1048 static int sqlite3Close(sqlite3 *db, int forceZombie){
1049   if( !db ){
1050     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1051     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1052     return SQLITE_OK;
1053   }
1054   if( !sqlite3SafetyCheckSickOrOk(db) ){
1055     return SQLITE_MISUSE_BKPT;
1056   }
1057   sqlite3_mutex_enter(db->mutex);
1058   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1059     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1060   }
1061 
1062   /* Force xDisconnect calls on all virtual tables */
1063   disconnectAllVtab(db);
1064 
1065   /* If a transaction is open, the disconnectAllVtab() call above
1066   ** will not have called the xDisconnect() method on any virtual
1067   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1068   ** call will do so. We need to do this before the check for active
1069   ** SQL statements below, as the v-table implementation may be storing
1070   ** some prepared statements internally.
1071   */
1072   sqlite3VtabRollback(db);
1073 
1074   /* Legacy behavior (sqlite3_close() behavior) is to return
1075   ** SQLITE_BUSY if the connection can not be closed immediately.
1076   */
1077   if( !forceZombie && connectionIsBusy(db) ){
1078     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1079        "statements or unfinished backups");
1080     sqlite3_mutex_leave(db->mutex);
1081     return SQLITE_BUSY;
1082   }
1083 
1084 #ifdef SQLITE_ENABLE_SQLLOG
1085   if( sqlite3GlobalConfig.xSqllog ){
1086     /* Closing the handle. Fourth parameter is passed the value 2. */
1087     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1088   }
1089 #endif
1090 
1091   /* Convert the connection into a zombie and then close it.
1092   */
1093   db->magic = SQLITE_MAGIC_ZOMBIE;
1094   sqlite3LeaveMutexAndCloseZombie(db);
1095   return SQLITE_OK;
1096 }
1097 
1098 /*
1099 ** Two variations on the public interface for closing a database
1100 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1101 ** leaves the connection option if there are unfinalized prepared
1102 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1103 ** version forces the connection to become a zombie if there are
1104 ** unclosed resources, and arranges for deallocation when the last
1105 ** prepare statement or sqlite3_backup closes.
1106 */
1107 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1108 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1109 
1110 
1111 /*
1112 ** Close the mutex on database connection db.
1113 **
1114 ** Furthermore, if database connection db is a zombie (meaning that there
1115 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1116 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1117 ** finished, then free all resources.
1118 */
1119 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1120   HashElem *i;                    /* Hash table iterator */
1121   int j;
1122 
1123   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1124   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1125   ** then just leave the mutex and return.
1126   */
1127   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1128     sqlite3_mutex_leave(db->mutex);
1129     return;
1130   }
1131 
1132   /* If we reach this point, it means that the database connection has
1133   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1134   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1135   ** go ahead and free all resources.
1136   */
1137 
1138   /* If a transaction is open, roll it back. This also ensures that if
1139   ** any database schemas have been modified by an uncommitted transaction
1140   ** they are reset. And that the required b-tree mutex is held to make
1141   ** the pager rollback and schema reset an atomic operation. */
1142   sqlite3RollbackAll(db, SQLITE_OK);
1143 
1144   /* Free any outstanding Savepoint structures. */
1145   sqlite3CloseSavepoints(db);
1146 
1147   /* Close all database connections */
1148   for(j=0; j<db->nDb; j++){
1149     struct Db *pDb = &db->aDb[j];
1150     if( pDb->pBt ){
1151       sqlite3BtreeClose(pDb->pBt);
1152       pDb->pBt = 0;
1153       if( j!=1 ){
1154         pDb->pSchema = 0;
1155       }
1156     }
1157   }
1158   /* Clear the TEMP schema separately and last */
1159   if( db->aDb[1].pSchema ){
1160     sqlite3SchemaClear(db->aDb[1].pSchema);
1161   }
1162   sqlite3VtabUnlockList(db);
1163 
1164   /* Free up the array of auxiliary databases */
1165   sqlite3CollapseDatabaseArray(db);
1166   assert( db->nDb<=2 );
1167   assert( db->aDb==db->aDbStatic );
1168 
1169   /* Tell the code in notify.c that the connection no longer holds any
1170   ** locks and does not require any further unlock-notify callbacks.
1171   */
1172   sqlite3ConnectionClosed(db);
1173 
1174   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1175     FuncDef *pNext, *p;
1176     p = sqliteHashData(i);
1177     do{
1178       functionDestroy(db, p);
1179       pNext = p->pNext;
1180       sqlite3DbFree(db, p);
1181       p = pNext;
1182     }while( p );
1183   }
1184   sqlite3HashClear(&db->aFunc);
1185   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1186     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1187     /* Invoke any destructors registered for collation sequence user data. */
1188     for(j=0; j<3; j++){
1189       if( pColl[j].xDel ){
1190         pColl[j].xDel(pColl[j].pUser);
1191       }
1192     }
1193     sqlite3DbFree(db, pColl);
1194   }
1195   sqlite3HashClear(&db->aCollSeq);
1196 #ifndef SQLITE_OMIT_VIRTUALTABLE
1197   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1198     Module *pMod = (Module *)sqliteHashData(i);
1199     if( pMod->xDestroy ){
1200       pMod->xDestroy(pMod->pAux);
1201     }
1202     sqlite3VtabEponymousTableClear(db, pMod);
1203     sqlite3DbFree(db, pMod);
1204   }
1205   sqlite3HashClear(&db->aModule);
1206 #endif
1207 
1208   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1209   sqlite3ValueFree(db->pErr);
1210   sqlite3CloseExtensions(db);
1211 #if SQLITE_USER_AUTHENTICATION
1212   sqlite3_free(db->auth.zAuthUser);
1213   sqlite3_free(db->auth.zAuthPW);
1214 #endif
1215 
1216   db->magic = SQLITE_MAGIC_ERROR;
1217 
1218   /* The temp-database schema is allocated differently from the other schema
1219   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1220   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1221   ** the same sqliteMalloc() as the one that allocates the database
1222   ** structure?
1223   */
1224   sqlite3DbFree(db, db->aDb[1].pSchema);
1225   sqlite3_mutex_leave(db->mutex);
1226   db->magic = SQLITE_MAGIC_CLOSED;
1227   sqlite3_mutex_free(db->mutex);
1228   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1229   if( db->lookaside.bMalloced ){
1230     sqlite3_free(db->lookaside.pStart);
1231   }
1232   sqlite3_free(db);
1233 }
1234 
1235 /*
1236 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1237 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1238 ** breaker") and made to return tripCode if there are any further
1239 ** attempts to use that cursor.  Read cursors remain open and valid
1240 ** but are "saved" in case the table pages are moved around.
1241 */
1242 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1243   int i;
1244   int inTrans = 0;
1245   int schemaChange;
1246   assert( sqlite3_mutex_held(db->mutex) );
1247   sqlite3BeginBenignMalloc();
1248 
1249   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1250   ** This is important in case the transaction being rolled back has
1251   ** modified the database schema. If the b-tree mutexes are not taken
1252   ** here, then another shared-cache connection might sneak in between
1253   ** the database rollback and schema reset, which can cause false
1254   ** corruption reports in some cases.  */
1255   sqlite3BtreeEnterAll(db);
1256   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1257 
1258   for(i=0; i<db->nDb; i++){
1259     Btree *p = db->aDb[i].pBt;
1260     if( p ){
1261       if( sqlite3BtreeIsInTrans(p) ){
1262         inTrans = 1;
1263       }
1264       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1265     }
1266   }
1267   sqlite3VtabRollback(db);
1268   sqlite3EndBenignMalloc();
1269 
1270   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1271     sqlite3ExpirePreparedStatements(db);
1272     sqlite3ResetAllSchemasOfConnection(db);
1273   }
1274   sqlite3BtreeLeaveAll(db);
1275 
1276   /* Any deferred constraint violations have now been resolved. */
1277   db->nDeferredCons = 0;
1278   db->nDeferredImmCons = 0;
1279   db->flags &= ~SQLITE_DeferFKs;
1280 
1281   /* If one has been configured, invoke the rollback-hook callback */
1282   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1283     db->xRollbackCallback(db->pRollbackArg);
1284   }
1285 }
1286 
1287 /*
1288 ** Return a static string containing the name corresponding to the error code
1289 ** specified in the argument.
1290 */
1291 #if defined(SQLITE_NEED_ERR_NAME)
1292 const char *sqlite3ErrName(int rc){
1293   const char *zName = 0;
1294   int i, origRc = rc;
1295   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1296     switch( rc ){
1297       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1298       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1299       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1300       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1301       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1302       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1303       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1304       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1305       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1306       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1307       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1308       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1309       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1310       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1311       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1312       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1313       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1314       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1315       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1316       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1317       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1318       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1319       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1320       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1321       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1322       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1323       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1324       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1325       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1326       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1327       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1328       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1329                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1330       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1331       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1332       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1333       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1334       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1335       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1336       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1337       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1338       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1339       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1340       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1341       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1342       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1343       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1344       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1345       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1346       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1347       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1348       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1349       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1350       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1351       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1352       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1353       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1354       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1355       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1356       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1357       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1358       case SQLITE_CONSTRAINT_FOREIGNKEY:
1359                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1360       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1361       case SQLITE_CONSTRAINT_PRIMARYKEY:
1362                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1363       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1364       case SQLITE_CONSTRAINT_COMMITHOOK:
1365                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1366       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1367       case SQLITE_CONSTRAINT_FUNCTION:
1368                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1369       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1370       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1371       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1372       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1373       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1374       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1375       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1376       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1377       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1378       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1379       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1380       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1381                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1382       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1383       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1384       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1385     }
1386   }
1387   if( zName==0 ){
1388     static char zBuf[50];
1389     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1390     zName = zBuf;
1391   }
1392   return zName;
1393 }
1394 #endif
1395 
1396 /*
1397 ** Return a static string that describes the kind of error specified in the
1398 ** argument.
1399 */
1400 const char *sqlite3ErrStr(int rc){
1401   static const char* const aMsg[] = {
1402     /* SQLITE_OK          */ "not an error",
1403     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1404     /* SQLITE_INTERNAL    */ 0,
1405     /* SQLITE_PERM        */ "access permission denied",
1406     /* SQLITE_ABORT       */ "callback requested query abort",
1407     /* SQLITE_BUSY        */ "database is locked",
1408     /* SQLITE_LOCKED      */ "database table is locked",
1409     /* SQLITE_NOMEM       */ "out of memory",
1410     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1411     /* SQLITE_INTERRUPT   */ "interrupted",
1412     /* SQLITE_IOERR       */ "disk I/O error",
1413     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1414     /* SQLITE_NOTFOUND    */ "unknown operation",
1415     /* SQLITE_FULL        */ "database or disk is full",
1416     /* SQLITE_CANTOPEN    */ "unable to open database file",
1417     /* SQLITE_PROTOCOL    */ "locking protocol",
1418     /* SQLITE_EMPTY       */ "table contains no data",
1419     /* SQLITE_SCHEMA      */ "database schema has changed",
1420     /* SQLITE_TOOBIG      */ "string or blob too big",
1421     /* SQLITE_CONSTRAINT  */ "constraint failed",
1422     /* SQLITE_MISMATCH    */ "datatype mismatch",
1423     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1424     /* SQLITE_NOLFS       */ "large file support is disabled",
1425     /* SQLITE_AUTH        */ "authorization denied",
1426     /* SQLITE_FORMAT      */ "auxiliary database format error",
1427     /* SQLITE_RANGE       */ "bind or column index out of range",
1428     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1429   };
1430   const char *zErr = "unknown error";
1431   switch( rc ){
1432     case SQLITE_ABORT_ROLLBACK: {
1433       zErr = "abort due to ROLLBACK";
1434       break;
1435     }
1436     default: {
1437       rc &= 0xff;
1438       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1439         zErr = aMsg[rc];
1440       }
1441       break;
1442     }
1443   }
1444   return zErr;
1445 }
1446 
1447 /*
1448 ** This routine implements a busy callback that sleeps and tries
1449 ** again until a timeout value is reached.  The timeout value is
1450 ** an integer number of milliseconds passed in as the first
1451 ** argument.
1452 */
1453 static int sqliteDefaultBusyCallback(
1454  void *ptr,               /* Database connection */
1455  int count                /* Number of times table has been busy */
1456 ){
1457 #if SQLITE_OS_WIN || HAVE_USLEEP
1458   static const u8 delays[] =
1459      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1460   static const u8 totals[] =
1461      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1462 # define NDELAY ArraySize(delays)
1463   sqlite3 *db = (sqlite3 *)ptr;
1464   int timeout = db->busyTimeout;
1465   int delay, prior;
1466 
1467   assert( count>=0 );
1468   if( count < NDELAY ){
1469     delay = delays[count];
1470     prior = totals[count];
1471   }else{
1472     delay = delays[NDELAY-1];
1473     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1474   }
1475   if( prior + delay > timeout ){
1476     delay = timeout - prior;
1477     if( delay<=0 ) return 0;
1478   }
1479   sqlite3OsSleep(db->pVfs, delay*1000);
1480   return 1;
1481 #else
1482   sqlite3 *db = (sqlite3 *)ptr;
1483   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1484   if( (count+1)*1000 > timeout ){
1485     return 0;
1486   }
1487   sqlite3OsSleep(db->pVfs, 1000000);
1488   return 1;
1489 #endif
1490 }
1491 
1492 /*
1493 ** Invoke the given busy handler.
1494 **
1495 ** This routine is called when an operation failed with a lock.
1496 ** If this routine returns non-zero, the lock is retried.  If it
1497 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1498 */
1499 int sqlite3InvokeBusyHandler(BusyHandler *p){
1500   int rc;
1501   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1502   rc = p->xFunc(p->pArg, p->nBusy);
1503   if( rc==0 ){
1504     p->nBusy = -1;
1505   }else{
1506     p->nBusy++;
1507   }
1508   return rc;
1509 }
1510 
1511 /*
1512 ** This routine sets the busy callback for an Sqlite database to the
1513 ** given callback function with the given argument.
1514 */
1515 int sqlite3_busy_handler(
1516   sqlite3 *db,
1517   int (*xBusy)(void*,int),
1518   void *pArg
1519 ){
1520 #ifdef SQLITE_ENABLE_API_ARMOR
1521   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1522 #endif
1523   sqlite3_mutex_enter(db->mutex);
1524   db->busyHandler.xFunc = xBusy;
1525   db->busyHandler.pArg = pArg;
1526   db->busyHandler.nBusy = 0;
1527   db->busyTimeout = 0;
1528   sqlite3_mutex_leave(db->mutex);
1529   return SQLITE_OK;
1530 }
1531 
1532 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1533 /*
1534 ** This routine sets the progress callback for an Sqlite database to the
1535 ** given callback function with the given argument. The progress callback will
1536 ** be invoked every nOps opcodes.
1537 */
1538 void sqlite3_progress_handler(
1539   sqlite3 *db,
1540   int nOps,
1541   int (*xProgress)(void*),
1542   void *pArg
1543 ){
1544 #ifdef SQLITE_ENABLE_API_ARMOR
1545   if( !sqlite3SafetyCheckOk(db) ){
1546     (void)SQLITE_MISUSE_BKPT;
1547     return;
1548   }
1549 #endif
1550   sqlite3_mutex_enter(db->mutex);
1551   if( nOps>0 ){
1552     db->xProgress = xProgress;
1553     db->nProgressOps = (unsigned)nOps;
1554     db->pProgressArg = pArg;
1555   }else{
1556     db->xProgress = 0;
1557     db->nProgressOps = 0;
1558     db->pProgressArg = 0;
1559   }
1560   sqlite3_mutex_leave(db->mutex);
1561 }
1562 #endif
1563 
1564 
1565 /*
1566 ** This routine installs a default busy handler that waits for the
1567 ** specified number of milliseconds before returning 0.
1568 */
1569 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1570 #ifdef SQLITE_ENABLE_API_ARMOR
1571   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1572 #endif
1573   if( ms>0 ){
1574     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1575     db->busyTimeout = ms;
1576   }else{
1577     sqlite3_busy_handler(db, 0, 0);
1578   }
1579   return SQLITE_OK;
1580 }
1581 
1582 /*
1583 ** Cause any pending operation to stop at its earliest opportunity.
1584 */
1585 void sqlite3_interrupt(sqlite3 *db){
1586 #ifdef SQLITE_ENABLE_API_ARMOR
1587   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1588     (void)SQLITE_MISUSE_BKPT;
1589     return;
1590   }
1591 #endif
1592   db->u1.isInterrupted = 1;
1593 }
1594 
1595 
1596 /*
1597 ** This function is exactly the same as sqlite3_create_function(), except
1598 ** that it is designed to be called by internal code. The difference is
1599 ** that if a malloc() fails in sqlite3_create_function(), an error code
1600 ** is returned and the mallocFailed flag cleared.
1601 */
1602 int sqlite3CreateFunc(
1603   sqlite3 *db,
1604   const char *zFunctionName,
1605   int nArg,
1606   int enc,
1607   void *pUserData,
1608   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1609   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1610   void (*xFinal)(sqlite3_context*),
1611   FuncDestructor *pDestructor
1612 ){
1613   FuncDef *p;
1614   int nName;
1615   int extraFlags;
1616 
1617   assert( sqlite3_mutex_held(db->mutex) );
1618   if( zFunctionName==0 ||
1619       (xSFunc && (xFinal || xStep)) ||
1620       (!xSFunc && (xFinal && !xStep)) ||
1621       (!xSFunc && (!xFinal && xStep)) ||
1622       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1623       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1624     return SQLITE_MISUSE_BKPT;
1625   }
1626 
1627   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1628   extraFlags = enc &  SQLITE_DETERMINISTIC;
1629   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1630 
1631 #ifndef SQLITE_OMIT_UTF16
1632   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1633   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1634   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1635   **
1636   ** If SQLITE_ANY is specified, add three versions of the function
1637   ** to the hash table.
1638   */
1639   if( enc==SQLITE_UTF16 ){
1640     enc = SQLITE_UTF16NATIVE;
1641   }else if( enc==SQLITE_ANY ){
1642     int rc;
1643     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1644          pUserData, xSFunc, xStep, xFinal, pDestructor);
1645     if( rc==SQLITE_OK ){
1646       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1647           pUserData, xSFunc, xStep, xFinal, pDestructor);
1648     }
1649     if( rc!=SQLITE_OK ){
1650       return rc;
1651     }
1652     enc = SQLITE_UTF16BE;
1653   }
1654 #else
1655   enc = SQLITE_UTF8;
1656 #endif
1657 
1658   /* Check if an existing function is being overridden or deleted. If so,
1659   ** and there are active VMs, then return SQLITE_BUSY. If a function
1660   ** is being overridden/deleted but there are no active VMs, allow the
1661   ** operation to continue but invalidate all precompiled statements.
1662   */
1663   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1664   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1665     if( db->nVdbeActive ){
1666       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1667         "unable to delete/modify user-function due to active statements");
1668       assert( !db->mallocFailed );
1669       return SQLITE_BUSY;
1670     }else{
1671       sqlite3ExpirePreparedStatements(db);
1672     }
1673   }
1674 
1675   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1676   assert(p || db->mallocFailed);
1677   if( !p ){
1678     return SQLITE_NOMEM_BKPT;
1679   }
1680 
1681   /* If an older version of the function with a configured destructor is
1682   ** being replaced invoke the destructor function here. */
1683   functionDestroy(db, p);
1684 
1685   if( pDestructor ){
1686     pDestructor->nRef++;
1687   }
1688   p->u.pDestructor = pDestructor;
1689   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1690   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1691   p->xSFunc = xSFunc ? xSFunc : xStep;
1692   p->xFinalize = xFinal;
1693   p->pUserData = pUserData;
1694   p->nArg = (u16)nArg;
1695   return SQLITE_OK;
1696 }
1697 
1698 /*
1699 ** Create new user functions.
1700 */
1701 int sqlite3_create_function(
1702   sqlite3 *db,
1703   const char *zFunc,
1704   int nArg,
1705   int enc,
1706   void *p,
1707   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1708   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1709   void (*xFinal)(sqlite3_context*)
1710 ){
1711   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1712                                     xFinal, 0);
1713 }
1714 
1715 int sqlite3_create_function_v2(
1716   sqlite3 *db,
1717   const char *zFunc,
1718   int nArg,
1719   int enc,
1720   void *p,
1721   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1722   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1723   void (*xFinal)(sqlite3_context*),
1724   void (*xDestroy)(void *)
1725 ){
1726   int rc = SQLITE_ERROR;
1727   FuncDestructor *pArg = 0;
1728 
1729 #ifdef SQLITE_ENABLE_API_ARMOR
1730   if( !sqlite3SafetyCheckOk(db) ){
1731     return SQLITE_MISUSE_BKPT;
1732   }
1733 #endif
1734   sqlite3_mutex_enter(db->mutex);
1735   if( xDestroy ){
1736     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1737     if( !pArg ){
1738       xDestroy(p);
1739       goto out;
1740     }
1741     pArg->xDestroy = xDestroy;
1742     pArg->pUserData = p;
1743   }
1744   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1745   if( pArg && pArg->nRef==0 ){
1746     assert( rc!=SQLITE_OK );
1747     xDestroy(p);
1748     sqlite3DbFree(db, pArg);
1749   }
1750 
1751  out:
1752   rc = sqlite3ApiExit(db, rc);
1753   sqlite3_mutex_leave(db->mutex);
1754   return rc;
1755 }
1756 
1757 #ifndef SQLITE_OMIT_UTF16
1758 int sqlite3_create_function16(
1759   sqlite3 *db,
1760   const void *zFunctionName,
1761   int nArg,
1762   int eTextRep,
1763   void *p,
1764   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1765   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1766   void (*xFinal)(sqlite3_context*)
1767 ){
1768   int rc;
1769   char *zFunc8;
1770 
1771 #ifdef SQLITE_ENABLE_API_ARMOR
1772   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1773 #endif
1774   sqlite3_mutex_enter(db->mutex);
1775   assert( !db->mallocFailed );
1776   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1777   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1778   sqlite3DbFree(db, zFunc8);
1779   rc = sqlite3ApiExit(db, rc);
1780   sqlite3_mutex_leave(db->mutex);
1781   return rc;
1782 }
1783 #endif
1784 
1785 
1786 /*
1787 ** Declare that a function has been overloaded by a virtual table.
1788 **
1789 ** If the function already exists as a regular global function, then
1790 ** this routine is a no-op.  If the function does not exist, then create
1791 ** a new one that always throws a run-time error.
1792 **
1793 ** When virtual tables intend to provide an overloaded function, they
1794 ** should call this routine to make sure the global function exists.
1795 ** A global function must exist in order for name resolution to work
1796 ** properly.
1797 */
1798 int sqlite3_overload_function(
1799   sqlite3 *db,
1800   const char *zName,
1801   int nArg
1802 ){
1803   int rc = SQLITE_OK;
1804 
1805 #ifdef SQLITE_ENABLE_API_ARMOR
1806   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1807     return SQLITE_MISUSE_BKPT;
1808   }
1809 #endif
1810   sqlite3_mutex_enter(db->mutex);
1811   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1812     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1813                            0, sqlite3InvalidFunction, 0, 0, 0);
1814   }
1815   rc = sqlite3ApiExit(db, rc);
1816   sqlite3_mutex_leave(db->mutex);
1817   return rc;
1818 }
1819 
1820 #ifndef SQLITE_OMIT_TRACE
1821 /*
1822 ** Register a trace function.  The pArg from the previously registered trace
1823 ** is returned.
1824 **
1825 ** A NULL trace function means that no tracing is executes.  A non-NULL
1826 ** trace is a pointer to a function that is invoked at the start of each
1827 ** SQL statement.
1828 */
1829 #ifndef SQLITE_OMIT_DEPRECATED
1830 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1831   void *pOld;
1832 
1833 #ifdef SQLITE_ENABLE_API_ARMOR
1834   if( !sqlite3SafetyCheckOk(db) ){
1835     (void)SQLITE_MISUSE_BKPT;
1836     return 0;
1837   }
1838 #endif
1839   sqlite3_mutex_enter(db->mutex);
1840   pOld = db->pTraceArg;
1841   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
1842   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
1843   db->pTraceArg = pArg;
1844   sqlite3_mutex_leave(db->mutex);
1845   return pOld;
1846 }
1847 #endif /* SQLITE_OMIT_DEPRECATED */
1848 
1849 /* Register a trace callback using the version-2 interface.
1850 */
1851 int sqlite3_trace_v2(
1852   sqlite3 *db,                               /* Trace this connection */
1853   unsigned mTrace,                           /* Mask of events to be traced */
1854   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
1855   void *pArg                                 /* Context */
1856 ){
1857 #ifdef SQLITE_ENABLE_API_ARMOR
1858   if( !sqlite3SafetyCheckOk(db) ){
1859     return SQLITE_MISUSE_BKPT;
1860   }
1861 #endif
1862   sqlite3_mutex_enter(db->mutex);
1863   if( mTrace==0 ) xTrace = 0;
1864   if( xTrace==0 ) mTrace = 0;
1865   db->mTrace = mTrace;
1866   db->xTrace = xTrace;
1867   db->pTraceArg = pArg;
1868   sqlite3_mutex_leave(db->mutex);
1869   return SQLITE_OK;
1870 }
1871 
1872 #ifndef SQLITE_OMIT_DEPRECATED
1873 /*
1874 ** Register a profile function.  The pArg from the previously registered
1875 ** profile function is returned.
1876 **
1877 ** A NULL profile function means that no profiling is executes.  A non-NULL
1878 ** profile is a pointer to a function that is invoked at the conclusion of
1879 ** each SQL statement that is run.
1880 */
1881 void *sqlite3_profile(
1882   sqlite3 *db,
1883   void (*xProfile)(void*,const char*,sqlite_uint64),
1884   void *pArg
1885 ){
1886   void *pOld;
1887 
1888 #ifdef SQLITE_ENABLE_API_ARMOR
1889   if( !sqlite3SafetyCheckOk(db) ){
1890     (void)SQLITE_MISUSE_BKPT;
1891     return 0;
1892   }
1893 #endif
1894   sqlite3_mutex_enter(db->mutex);
1895   pOld = db->pProfileArg;
1896   db->xProfile = xProfile;
1897   db->pProfileArg = pArg;
1898   sqlite3_mutex_leave(db->mutex);
1899   return pOld;
1900 }
1901 #endif /* SQLITE_OMIT_DEPRECATED */
1902 #endif /* SQLITE_OMIT_TRACE */
1903 
1904 /*
1905 ** Register a function to be invoked when a transaction commits.
1906 ** If the invoked function returns non-zero, then the commit becomes a
1907 ** rollback.
1908 */
1909 void *sqlite3_commit_hook(
1910   sqlite3 *db,              /* Attach the hook to this database */
1911   int (*xCallback)(void*),  /* Function to invoke on each commit */
1912   void *pArg                /* Argument to the function */
1913 ){
1914   void *pOld;
1915 
1916 #ifdef SQLITE_ENABLE_API_ARMOR
1917   if( !sqlite3SafetyCheckOk(db) ){
1918     (void)SQLITE_MISUSE_BKPT;
1919     return 0;
1920   }
1921 #endif
1922   sqlite3_mutex_enter(db->mutex);
1923   pOld = db->pCommitArg;
1924   db->xCommitCallback = xCallback;
1925   db->pCommitArg = pArg;
1926   sqlite3_mutex_leave(db->mutex);
1927   return pOld;
1928 }
1929 
1930 /*
1931 ** Register a callback to be invoked each time a row is updated,
1932 ** inserted or deleted using this database connection.
1933 */
1934 void *sqlite3_update_hook(
1935   sqlite3 *db,              /* Attach the hook to this database */
1936   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1937   void *pArg                /* Argument to the function */
1938 ){
1939   void *pRet;
1940 
1941 #ifdef SQLITE_ENABLE_API_ARMOR
1942   if( !sqlite3SafetyCheckOk(db) ){
1943     (void)SQLITE_MISUSE_BKPT;
1944     return 0;
1945   }
1946 #endif
1947   sqlite3_mutex_enter(db->mutex);
1948   pRet = db->pUpdateArg;
1949   db->xUpdateCallback = xCallback;
1950   db->pUpdateArg = pArg;
1951   sqlite3_mutex_leave(db->mutex);
1952   return pRet;
1953 }
1954 
1955 /*
1956 ** Register a callback to be invoked each time a transaction is rolled
1957 ** back by this database connection.
1958 */
1959 void *sqlite3_rollback_hook(
1960   sqlite3 *db,              /* Attach the hook to this database */
1961   void (*xCallback)(void*), /* Callback function */
1962   void *pArg                /* Argument to the function */
1963 ){
1964   void *pRet;
1965 
1966 #ifdef SQLITE_ENABLE_API_ARMOR
1967   if( !sqlite3SafetyCheckOk(db) ){
1968     (void)SQLITE_MISUSE_BKPT;
1969     return 0;
1970   }
1971 #endif
1972   sqlite3_mutex_enter(db->mutex);
1973   pRet = db->pRollbackArg;
1974   db->xRollbackCallback = xCallback;
1975   db->pRollbackArg = pArg;
1976   sqlite3_mutex_leave(db->mutex);
1977   return pRet;
1978 }
1979 
1980 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1981 /*
1982 ** Register a callback to be invoked each time a row is updated,
1983 ** inserted or deleted using this database connection.
1984 */
1985 void *sqlite3_preupdate_hook(
1986   sqlite3 *db,              /* Attach the hook to this database */
1987   void(*xCallback)(         /* Callback function */
1988     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
1989   void *pArg                /* First callback argument */
1990 ){
1991   void *pRet;
1992   sqlite3_mutex_enter(db->mutex);
1993   pRet = db->pPreUpdateArg;
1994   db->xPreUpdateCallback = xCallback;
1995   db->pPreUpdateArg = pArg;
1996   sqlite3_mutex_leave(db->mutex);
1997   return pRet;
1998 }
1999 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2000 
2001 #ifndef SQLITE_OMIT_WAL
2002 /*
2003 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2004 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2005 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2006 ** wal_autocheckpoint()).
2007 */
2008 int sqlite3WalDefaultHook(
2009   void *pClientData,     /* Argument */
2010   sqlite3 *db,           /* Connection */
2011   const char *zDb,       /* Database */
2012   int nFrame             /* Size of WAL */
2013 ){
2014   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2015     sqlite3BeginBenignMalloc();
2016     sqlite3_wal_checkpoint(db, zDb);
2017     sqlite3EndBenignMalloc();
2018   }
2019   return SQLITE_OK;
2020 }
2021 #endif /* SQLITE_OMIT_WAL */
2022 
2023 /*
2024 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2025 ** a database after committing a transaction if there are nFrame or
2026 ** more frames in the log file. Passing zero or a negative value as the
2027 ** nFrame parameter disables automatic checkpoints entirely.
2028 **
2029 ** The callback registered by this function replaces any existing callback
2030 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2031 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2032 ** configured by this function.
2033 */
2034 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2035 #ifdef SQLITE_OMIT_WAL
2036   UNUSED_PARAMETER(db);
2037   UNUSED_PARAMETER(nFrame);
2038 #else
2039 #ifdef SQLITE_ENABLE_API_ARMOR
2040   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2041 #endif
2042   if( nFrame>0 ){
2043     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2044   }else{
2045     sqlite3_wal_hook(db, 0, 0);
2046   }
2047 #endif
2048   return SQLITE_OK;
2049 }
2050 
2051 /*
2052 ** Register a callback to be invoked each time a transaction is written
2053 ** into the write-ahead-log by this database connection.
2054 */
2055 void *sqlite3_wal_hook(
2056   sqlite3 *db,                    /* Attach the hook to this db handle */
2057   int(*xCallback)(void *, sqlite3*, const char*, int),
2058   void *pArg                      /* First argument passed to xCallback() */
2059 ){
2060 #ifndef SQLITE_OMIT_WAL
2061   void *pRet;
2062 #ifdef SQLITE_ENABLE_API_ARMOR
2063   if( !sqlite3SafetyCheckOk(db) ){
2064     (void)SQLITE_MISUSE_BKPT;
2065     return 0;
2066   }
2067 #endif
2068   sqlite3_mutex_enter(db->mutex);
2069   pRet = db->pWalArg;
2070   db->xWalCallback = xCallback;
2071   db->pWalArg = pArg;
2072   sqlite3_mutex_leave(db->mutex);
2073   return pRet;
2074 #else
2075   return 0;
2076 #endif
2077 }
2078 
2079 /*
2080 ** Checkpoint database zDb.
2081 */
2082 int sqlite3_wal_checkpoint_v2(
2083   sqlite3 *db,                    /* Database handle */
2084   const char *zDb,                /* Name of attached database (or NULL) */
2085   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2086   int *pnLog,                     /* OUT: Size of WAL log in frames */
2087   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2088 ){
2089 #ifdef SQLITE_OMIT_WAL
2090   return SQLITE_OK;
2091 #else
2092   int rc;                         /* Return code */
2093   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2094 
2095 #ifdef SQLITE_ENABLE_API_ARMOR
2096   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2097 #endif
2098 
2099   /* Initialize the output variables to -1 in case an error occurs. */
2100   if( pnLog ) *pnLog = -1;
2101   if( pnCkpt ) *pnCkpt = -1;
2102 
2103   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2104   assert( SQLITE_CHECKPOINT_FULL==1 );
2105   assert( SQLITE_CHECKPOINT_RESTART==2 );
2106   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2107   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2108     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2109     ** mode: */
2110     return SQLITE_MISUSE;
2111   }
2112 
2113   sqlite3_mutex_enter(db->mutex);
2114   if( zDb && zDb[0] ){
2115     iDb = sqlite3FindDbName(db, zDb);
2116   }
2117   if( iDb<0 ){
2118     rc = SQLITE_ERROR;
2119     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2120   }else{
2121     db->busyHandler.nBusy = 0;
2122     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2123     sqlite3Error(db, rc);
2124   }
2125   rc = sqlite3ApiExit(db, rc);
2126 
2127   /* If there are no active statements, clear the interrupt flag at this
2128   ** point.  */
2129   if( db->nVdbeActive==0 ){
2130     db->u1.isInterrupted = 0;
2131   }
2132 
2133   sqlite3_mutex_leave(db->mutex);
2134   return rc;
2135 #endif
2136 }
2137 
2138 
2139 /*
2140 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2141 ** to contains a zero-length string, all attached databases are
2142 ** checkpointed.
2143 */
2144 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2145   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2146   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2147   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2148 }
2149 
2150 #ifndef SQLITE_OMIT_WAL
2151 /*
2152 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2153 ** not currently open in WAL mode.
2154 **
2155 ** If a transaction is open on the database being checkpointed, this
2156 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2157 ** an error occurs while running the checkpoint, an SQLite error code is
2158 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2159 **
2160 ** The mutex on database handle db should be held by the caller. The mutex
2161 ** associated with the specific b-tree being checkpointed is taken by
2162 ** this function while the checkpoint is running.
2163 **
2164 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2165 ** checkpointed. If an error is encountered it is returned immediately -
2166 ** no attempt is made to checkpoint any remaining databases.
2167 **
2168 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2169 */
2170 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2171   int rc = SQLITE_OK;             /* Return code */
2172   int i;                          /* Used to iterate through attached dbs */
2173   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2174 
2175   assert( sqlite3_mutex_held(db->mutex) );
2176   assert( !pnLog || *pnLog==-1 );
2177   assert( !pnCkpt || *pnCkpt==-1 );
2178 
2179   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2180     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2181       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2182       pnLog = 0;
2183       pnCkpt = 0;
2184       if( rc==SQLITE_BUSY ){
2185         bBusy = 1;
2186         rc = SQLITE_OK;
2187       }
2188     }
2189   }
2190 
2191   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2192 }
2193 #endif /* SQLITE_OMIT_WAL */
2194 
2195 /*
2196 ** This function returns true if main-memory should be used instead of
2197 ** a temporary file for transient pager files and statement journals.
2198 ** The value returned depends on the value of db->temp_store (runtime
2199 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2200 ** following table describes the relationship between these two values
2201 ** and this functions return value.
2202 **
2203 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2204 **   -----------------     --------------     ------------------------------
2205 **   0                     any                file      (return 0)
2206 **   1                     1                  file      (return 0)
2207 **   1                     2                  memory    (return 1)
2208 **   1                     0                  file      (return 0)
2209 **   2                     1                  file      (return 0)
2210 **   2                     2                  memory    (return 1)
2211 **   2                     0                  memory    (return 1)
2212 **   3                     any                memory    (return 1)
2213 */
2214 int sqlite3TempInMemory(const sqlite3 *db){
2215 #if SQLITE_TEMP_STORE==1
2216   return ( db->temp_store==2 );
2217 #endif
2218 #if SQLITE_TEMP_STORE==2
2219   return ( db->temp_store!=1 );
2220 #endif
2221 #if SQLITE_TEMP_STORE==3
2222   UNUSED_PARAMETER(db);
2223   return 1;
2224 #endif
2225 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2226   UNUSED_PARAMETER(db);
2227   return 0;
2228 #endif
2229 }
2230 
2231 /*
2232 ** Return UTF-8 encoded English language explanation of the most recent
2233 ** error.
2234 */
2235 const char *sqlite3_errmsg(sqlite3 *db){
2236   const char *z;
2237   if( !db ){
2238     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2239   }
2240   if( !sqlite3SafetyCheckSickOrOk(db) ){
2241     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2242   }
2243   sqlite3_mutex_enter(db->mutex);
2244   if( db->mallocFailed ){
2245     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2246   }else{
2247     testcase( db->pErr==0 );
2248     z = (char*)sqlite3_value_text(db->pErr);
2249     assert( !db->mallocFailed );
2250     if( z==0 ){
2251       z = sqlite3ErrStr(db->errCode);
2252     }
2253   }
2254   sqlite3_mutex_leave(db->mutex);
2255   return z;
2256 }
2257 
2258 #ifndef SQLITE_OMIT_UTF16
2259 /*
2260 ** Return UTF-16 encoded English language explanation of the most recent
2261 ** error.
2262 */
2263 const void *sqlite3_errmsg16(sqlite3 *db){
2264   static const u16 outOfMem[] = {
2265     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2266   };
2267   static const u16 misuse[] = {
2268     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2269     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2270     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2271     'o', 'u', 't', ' ',
2272     'o', 'f', ' ',
2273     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2274   };
2275 
2276   const void *z;
2277   if( !db ){
2278     return (void *)outOfMem;
2279   }
2280   if( !sqlite3SafetyCheckSickOrOk(db) ){
2281     return (void *)misuse;
2282   }
2283   sqlite3_mutex_enter(db->mutex);
2284   if( db->mallocFailed ){
2285     z = (void *)outOfMem;
2286   }else{
2287     z = sqlite3_value_text16(db->pErr);
2288     if( z==0 ){
2289       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2290       z = sqlite3_value_text16(db->pErr);
2291     }
2292     /* A malloc() may have failed within the call to sqlite3_value_text16()
2293     ** above. If this is the case, then the db->mallocFailed flag needs to
2294     ** be cleared before returning. Do this directly, instead of via
2295     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2296     */
2297     sqlite3OomClear(db);
2298   }
2299   sqlite3_mutex_leave(db->mutex);
2300   return z;
2301 }
2302 #endif /* SQLITE_OMIT_UTF16 */
2303 
2304 /*
2305 ** Return the most recent error code generated by an SQLite routine. If NULL is
2306 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2307 */
2308 int sqlite3_errcode(sqlite3 *db){
2309   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2310     return SQLITE_MISUSE_BKPT;
2311   }
2312   if( !db || db->mallocFailed ){
2313     return SQLITE_NOMEM_BKPT;
2314   }
2315   return db->errCode & db->errMask;
2316 }
2317 int sqlite3_extended_errcode(sqlite3 *db){
2318   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2319     return SQLITE_MISUSE_BKPT;
2320   }
2321   if( !db || db->mallocFailed ){
2322     return SQLITE_NOMEM_BKPT;
2323   }
2324   return db->errCode;
2325 }
2326 int sqlite3_system_errno(sqlite3 *db){
2327   return db ? db->iSysErrno : 0;
2328 }
2329 
2330 /*
2331 ** Return a string that describes the kind of error specified in the
2332 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2333 ** function.
2334 */
2335 const char *sqlite3_errstr(int rc){
2336   return sqlite3ErrStr(rc);
2337 }
2338 
2339 /*
2340 ** Create a new collating function for database "db".  The name is zName
2341 ** and the encoding is enc.
2342 */
2343 static int createCollation(
2344   sqlite3* db,
2345   const char *zName,
2346   u8 enc,
2347   void* pCtx,
2348   int(*xCompare)(void*,int,const void*,int,const void*),
2349   void(*xDel)(void*)
2350 ){
2351   CollSeq *pColl;
2352   int enc2;
2353 
2354   assert( sqlite3_mutex_held(db->mutex) );
2355 
2356   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2357   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2358   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2359   */
2360   enc2 = enc;
2361   testcase( enc2==SQLITE_UTF16 );
2362   testcase( enc2==SQLITE_UTF16_ALIGNED );
2363   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2364     enc2 = SQLITE_UTF16NATIVE;
2365   }
2366   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2367     return SQLITE_MISUSE_BKPT;
2368   }
2369 
2370   /* Check if this call is removing or replacing an existing collation
2371   ** sequence. If so, and there are active VMs, return busy. If there
2372   ** are no active VMs, invalidate any pre-compiled statements.
2373   */
2374   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2375   if( pColl && pColl->xCmp ){
2376     if( db->nVdbeActive ){
2377       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2378         "unable to delete/modify collation sequence due to active statements");
2379       return SQLITE_BUSY;
2380     }
2381     sqlite3ExpirePreparedStatements(db);
2382 
2383     /* If collation sequence pColl was created directly by a call to
2384     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2385     ** then any copies made by synthCollSeq() need to be invalidated.
2386     ** Also, collation destructor - CollSeq.xDel() - function may need
2387     ** to be called.
2388     */
2389     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2390       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2391       int j;
2392       for(j=0; j<3; j++){
2393         CollSeq *p = &aColl[j];
2394         if( p->enc==pColl->enc ){
2395           if( p->xDel ){
2396             p->xDel(p->pUser);
2397           }
2398           p->xCmp = 0;
2399         }
2400       }
2401     }
2402   }
2403 
2404   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2405   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2406   pColl->xCmp = xCompare;
2407   pColl->pUser = pCtx;
2408   pColl->xDel = xDel;
2409   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2410   sqlite3Error(db, SQLITE_OK);
2411   return SQLITE_OK;
2412 }
2413 
2414 
2415 /*
2416 ** This array defines hard upper bounds on limit values.  The
2417 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2418 ** #defines in sqlite3.h.
2419 */
2420 static const int aHardLimit[] = {
2421   SQLITE_MAX_LENGTH,
2422   SQLITE_MAX_SQL_LENGTH,
2423   SQLITE_MAX_COLUMN,
2424   SQLITE_MAX_EXPR_DEPTH,
2425   SQLITE_MAX_COMPOUND_SELECT,
2426   SQLITE_MAX_VDBE_OP,
2427   SQLITE_MAX_FUNCTION_ARG,
2428   SQLITE_MAX_ATTACHED,
2429   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2430   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2431   SQLITE_MAX_TRIGGER_DEPTH,
2432   SQLITE_MAX_WORKER_THREADS,
2433 };
2434 
2435 /*
2436 ** Make sure the hard limits are set to reasonable values
2437 */
2438 #if SQLITE_MAX_LENGTH<100
2439 # error SQLITE_MAX_LENGTH must be at least 100
2440 #endif
2441 #if SQLITE_MAX_SQL_LENGTH<100
2442 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2443 #endif
2444 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2445 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2446 #endif
2447 #if SQLITE_MAX_COMPOUND_SELECT<2
2448 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2449 #endif
2450 #if SQLITE_MAX_VDBE_OP<40
2451 # error SQLITE_MAX_VDBE_OP must be at least 40
2452 #endif
2453 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2454 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2455 #endif
2456 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2457 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2458 #endif
2459 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2460 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2461 #endif
2462 #if SQLITE_MAX_COLUMN>32767
2463 # error SQLITE_MAX_COLUMN must not exceed 32767
2464 #endif
2465 #if SQLITE_MAX_TRIGGER_DEPTH<1
2466 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2467 #endif
2468 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2469 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2470 #endif
2471 
2472 
2473 /*
2474 ** Change the value of a limit.  Report the old value.
2475 ** If an invalid limit index is supplied, report -1.
2476 ** Make no changes but still report the old value if the
2477 ** new limit is negative.
2478 **
2479 ** A new lower limit does not shrink existing constructs.
2480 ** It merely prevents new constructs that exceed the limit
2481 ** from forming.
2482 */
2483 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2484   int oldLimit;
2485 
2486 #ifdef SQLITE_ENABLE_API_ARMOR
2487   if( !sqlite3SafetyCheckOk(db) ){
2488     (void)SQLITE_MISUSE_BKPT;
2489     return -1;
2490   }
2491 #endif
2492 
2493   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2494   ** there is a hard upper bound set at compile-time by a C preprocessor
2495   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2496   ** "_MAX_".)
2497   */
2498   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2499   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2500   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2501   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2502   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2503   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2504   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2505   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2506   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2507                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2508   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2509   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2510   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2511   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2512 
2513 
2514   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2515     return -1;
2516   }
2517   oldLimit = db->aLimit[limitId];
2518   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2519     if( newLimit>aHardLimit[limitId] ){
2520       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2521     }
2522     db->aLimit[limitId] = newLimit;
2523   }
2524   return oldLimit;                     /* IMP: R-53341-35419 */
2525 }
2526 
2527 /*
2528 ** This function is used to parse both URIs and non-URI filenames passed by the
2529 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2530 ** URIs specified as part of ATTACH statements.
2531 **
2532 ** The first argument to this function is the name of the VFS to use (or
2533 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2534 ** query parameter. The second argument contains the URI (or non-URI filename)
2535 ** itself. When this function is called the *pFlags variable should contain
2536 ** the default flags to open the database handle with. The value stored in
2537 ** *pFlags may be updated before returning if the URI filename contains
2538 ** "cache=xxx" or "mode=xxx" query parameters.
2539 **
2540 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2541 ** the VFS that should be used to open the database file. *pzFile is set to
2542 ** point to a buffer containing the name of the file to open. It is the
2543 ** responsibility of the caller to eventually call sqlite3_free() to release
2544 ** this buffer.
2545 **
2546 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2547 ** may be set to point to a buffer containing an English language error
2548 ** message. It is the responsibility of the caller to eventually release
2549 ** this buffer by calling sqlite3_free().
2550 */
2551 int sqlite3ParseUri(
2552   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2553   const char *zUri,               /* Nul-terminated URI to parse */
2554   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2555   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2556   char **pzFile,                  /* OUT: Filename component of URI */
2557   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2558 ){
2559   int rc = SQLITE_OK;
2560   unsigned int flags = *pFlags;
2561   const char *zVfs = zDefaultVfs;
2562   char *zFile;
2563   char c;
2564   int nUri = sqlite3Strlen30(zUri);
2565 
2566   assert( *pzErrMsg==0 );
2567 
2568   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2569             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2570    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2571   ){
2572     char *zOpt;
2573     int eState;                   /* Parser state when parsing URI */
2574     int iIn;                      /* Input character index */
2575     int iOut = 0;                 /* Output character index */
2576     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2577 
2578     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2579     ** method that there may be extra parameters following the file-name.  */
2580     flags |= SQLITE_OPEN_URI;
2581 
2582     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2583     zFile = sqlite3_malloc64(nByte);
2584     if( !zFile ) return SQLITE_NOMEM_BKPT;
2585 
2586     iIn = 5;
2587 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2588     if( strncmp(zUri+5, "///", 3)==0 ){
2589       iIn = 7;
2590       /* The following condition causes URIs with five leading / characters
2591       ** like file://///host/path to be converted into UNCs like //host/path.
2592       ** The correct URI for that UNC has only two or four leading / characters
2593       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2594       ** common error, we are told, so we handle it as a special case. */
2595       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2596     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2597       iIn = 16;
2598     }
2599 #else
2600     /* Discard the scheme and authority segments of the URI. */
2601     if( zUri[5]=='/' && zUri[6]=='/' ){
2602       iIn = 7;
2603       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2604       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2605         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2606             iIn-7, &zUri[7]);
2607         rc = SQLITE_ERROR;
2608         goto parse_uri_out;
2609       }
2610     }
2611 #endif
2612 
2613     /* Copy the filename and any query parameters into the zFile buffer.
2614     ** Decode %HH escape codes along the way.
2615     **
2616     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2617     ** on the parsing context. As follows:
2618     **
2619     **   0: Parsing file-name.
2620     **   1: Parsing name section of a name=value query parameter.
2621     **   2: Parsing value section of a name=value query parameter.
2622     */
2623     eState = 0;
2624     while( (c = zUri[iIn])!=0 && c!='#' ){
2625       iIn++;
2626       if( c=='%'
2627        && sqlite3Isxdigit(zUri[iIn])
2628        && sqlite3Isxdigit(zUri[iIn+1])
2629       ){
2630         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2631         octet += sqlite3HexToInt(zUri[iIn++]);
2632 
2633         assert( octet>=0 && octet<256 );
2634         if( octet==0 ){
2635 #ifndef SQLITE_ENABLE_URI_00_ERROR
2636           /* This branch is taken when "%00" appears within the URI. In this
2637           ** case we ignore all text in the remainder of the path, name or
2638           ** value currently being parsed. So ignore the current character
2639           ** and skip to the next "?", "=" or "&", as appropriate. */
2640           while( (c = zUri[iIn])!=0 && c!='#'
2641               && (eState!=0 || c!='?')
2642               && (eState!=1 || (c!='=' && c!='&'))
2643               && (eState!=2 || c!='&')
2644           ){
2645             iIn++;
2646           }
2647           continue;
2648 #else
2649           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2650           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2651           rc = SQLITE_ERROR;
2652           goto parse_uri_out;
2653 #endif
2654         }
2655         c = octet;
2656       }else if( eState==1 && (c=='&' || c=='=') ){
2657         if( zFile[iOut-1]==0 ){
2658           /* An empty option name. Ignore this option altogether. */
2659           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2660           continue;
2661         }
2662         if( c=='&' ){
2663           zFile[iOut++] = '\0';
2664         }else{
2665           eState = 2;
2666         }
2667         c = 0;
2668       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2669         c = 0;
2670         eState = 1;
2671       }
2672       zFile[iOut++] = c;
2673     }
2674     if( eState==1 ) zFile[iOut++] = '\0';
2675     zFile[iOut++] = '\0';
2676     zFile[iOut++] = '\0';
2677 
2678     /* Check if there were any options specified that should be interpreted
2679     ** here. Options that are interpreted here include "vfs" and those that
2680     ** correspond to flags that may be passed to the sqlite3_open_v2()
2681     ** method. */
2682     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2683     while( zOpt[0] ){
2684       int nOpt = sqlite3Strlen30(zOpt);
2685       char *zVal = &zOpt[nOpt+1];
2686       int nVal = sqlite3Strlen30(zVal);
2687 
2688       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2689         zVfs = zVal;
2690       }else{
2691         struct OpenMode {
2692           const char *z;
2693           int mode;
2694         } *aMode = 0;
2695         char *zModeType = 0;
2696         int mask = 0;
2697         int limit = 0;
2698 
2699         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2700           static struct OpenMode aCacheMode[] = {
2701             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2702             { "private", SQLITE_OPEN_PRIVATECACHE },
2703             { 0, 0 }
2704           };
2705 
2706           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2707           aMode = aCacheMode;
2708           limit = mask;
2709           zModeType = "cache";
2710         }
2711         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2712           static struct OpenMode aOpenMode[] = {
2713             { "ro",  SQLITE_OPEN_READONLY },
2714             { "rw",  SQLITE_OPEN_READWRITE },
2715             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2716             { "memory", SQLITE_OPEN_MEMORY },
2717             { 0, 0 }
2718           };
2719 
2720           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2721                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2722           aMode = aOpenMode;
2723           limit = mask & flags;
2724           zModeType = "access";
2725         }
2726 
2727         if( aMode ){
2728           int i;
2729           int mode = 0;
2730           for(i=0; aMode[i].z; i++){
2731             const char *z = aMode[i].z;
2732             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2733               mode = aMode[i].mode;
2734               break;
2735             }
2736           }
2737           if( mode==0 ){
2738             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2739             rc = SQLITE_ERROR;
2740             goto parse_uri_out;
2741           }
2742           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2743             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2744                                         zModeType, zVal);
2745             rc = SQLITE_PERM;
2746             goto parse_uri_out;
2747           }
2748           flags = (flags & ~mask) | mode;
2749         }
2750       }
2751 
2752       zOpt = &zVal[nVal+1];
2753     }
2754 
2755   }else{
2756     zFile = sqlite3_malloc64(nUri+2);
2757     if( !zFile ) return SQLITE_NOMEM_BKPT;
2758     if( nUri ){
2759       memcpy(zFile, zUri, nUri);
2760     }
2761     zFile[nUri] = '\0';
2762     zFile[nUri+1] = '\0';
2763     flags &= ~SQLITE_OPEN_URI;
2764   }
2765 
2766   *ppVfs = sqlite3_vfs_find(zVfs);
2767   if( *ppVfs==0 ){
2768     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2769     rc = SQLITE_ERROR;
2770   }
2771  parse_uri_out:
2772   if( rc!=SQLITE_OK ){
2773     sqlite3_free(zFile);
2774     zFile = 0;
2775   }
2776   *pFlags = flags;
2777   *pzFile = zFile;
2778   return rc;
2779 }
2780 
2781 
2782 /*
2783 ** This routine does the work of opening a database on behalf of
2784 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2785 ** is UTF-8 encoded.
2786 */
2787 static int openDatabase(
2788   const char *zFilename, /* Database filename UTF-8 encoded */
2789   sqlite3 **ppDb,        /* OUT: Returned database handle */
2790   unsigned int flags,    /* Operational flags */
2791   const char *zVfs       /* Name of the VFS to use */
2792 ){
2793   sqlite3 *db;                    /* Store allocated handle here */
2794   int rc;                         /* Return code */
2795   int isThreadsafe;               /* True for threadsafe connections */
2796   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2797   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2798 
2799 #ifdef SQLITE_ENABLE_API_ARMOR
2800   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2801 #endif
2802   *ppDb = 0;
2803 #ifndef SQLITE_OMIT_AUTOINIT
2804   rc = sqlite3_initialize();
2805   if( rc ) return rc;
2806 #endif
2807 
2808   /* Only allow sensible combinations of bits in the flags argument.
2809   ** Throw an error if any non-sense combination is used.  If we
2810   ** do not block illegal combinations here, it could trigger
2811   ** assert() statements in deeper layers.  Sensible combinations
2812   ** are:
2813   **
2814   **  1:  SQLITE_OPEN_READONLY
2815   **  2:  SQLITE_OPEN_READWRITE
2816   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2817   */
2818   assert( SQLITE_OPEN_READONLY  == 0x01 );
2819   assert( SQLITE_OPEN_READWRITE == 0x02 );
2820   assert( SQLITE_OPEN_CREATE    == 0x04 );
2821   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2822   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2823   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2824   if( ((1<<(flags&7)) & 0x46)==0 ){
2825     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2826   }
2827 
2828   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2829     isThreadsafe = 0;
2830   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2831     isThreadsafe = 0;
2832   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2833     isThreadsafe = 1;
2834   }else{
2835     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2836   }
2837   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2838     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2839   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2840     flags |= SQLITE_OPEN_SHAREDCACHE;
2841   }
2842 
2843   /* Remove harmful bits from the flags parameter
2844   **
2845   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2846   ** dealt with in the previous code block.  Besides these, the only
2847   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2848   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2849   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2850   ** off all other flags.
2851   */
2852   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2853                SQLITE_OPEN_EXCLUSIVE |
2854                SQLITE_OPEN_MAIN_DB |
2855                SQLITE_OPEN_TEMP_DB |
2856                SQLITE_OPEN_TRANSIENT_DB |
2857                SQLITE_OPEN_MAIN_JOURNAL |
2858                SQLITE_OPEN_TEMP_JOURNAL |
2859                SQLITE_OPEN_SUBJOURNAL |
2860                SQLITE_OPEN_MASTER_JOURNAL |
2861                SQLITE_OPEN_NOMUTEX |
2862                SQLITE_OPEN_FULLMUTEX |
2863                SQLITE_OPEN_WAL
2864              );
2865 
2866   /* Allocate the sqlite data structure */
2867   db = sqlite3MallocZero( sizeof(sqlite3) );
2868   if( db==0 ) goto opendb_out;
2869   if( isThreadsafe ){
2870     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2871     if( db->mutex==0 ){
2872       sqlite3_free(db);
2873       db = 0;
2874       goto opendb_out;
2875     }
2876   }
2877   sqlite3_mutex_enter(db->mutex);
2878   db->errMask = 0xff;
2879   db->nDb = 2;
2880   db->magic = SQLITE_MAGIC_BUSY;
2881   db->aDb = db->aDbStatic;
2882 
2883   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2884   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2885   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2886   db->autoCommit = 1;
2887   db->nextAutovac = -1;
2888   db->szMmap = sqlite3GlobalConfig.szMmap;
2889   db->nextPagesize = 0;
2890   db->nMaxSorterMmap = 0x7FFFFFFF;
2891   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2892 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2893                  | SQLITE_AutoIndex
2894 #endif
2895 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2896                  | SQLITE_CkptFullFSync
2897 #endif
2898 #if SQLITE_DEFAULT_FILE_FORMAT<4
2899                  | SQLITE_LegacyFileFmt
2900 #endif
2901 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2902                  | SQLITE_LoadExtension
2903 #endif
2904 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2905                  | SQLITE_RecTriggers
2906 #endif
2907 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2908                  | SQLITE_ForeignKeys
2909 #endif
2910 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2911                  | SQLITE_ReverseOrder
2912 #endif
2913 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2914                  | SQLITE_CellSizeCk
2915 #endif
2916 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
2917                  | SQLITE_Fts3Tokenizer
2918 #endif
2919       ;
2920   sqlite3HashInit(&db->aCollSeq);
2921 #ifndef SQLITE_OMIT_VIRTUALTABLE
2922   sqlite3HashInit(&db->aModule);
2923 #endif
2924 
2925   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2926   ** and UTF-16, so add a version for each to avoid any unnecessary
2927   ** conversions. The only error that can occur here is a malloc() failure.
2928   **
2929   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2930   ** functions:
2931   */
2932   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2933   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2934   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2935   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2936   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2937   if( db->mallocFailed ){
2938     goto opendb_out;
2939   }
2940   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2941   ** strings is BINARY.
2942   */
2943   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2944   assert( db->pDfltColl!=0 );
2945 
2946   /* Parse the filename/URI argument. */
2947   db->openFlags = flags;
2948   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2949   if( rc!=SQLITE_OK ){
2950     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2951     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2952     sqlite3_free(zErrMsg);
2953     goto opendb_out;
2954   }
2955 
2956   /* Open the backend database driver */
2957   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2958                         flags | SQLITE_OPEN_MAIN_DB);
2959   if( rc!=SQLITE_OK ){
2960     if( rc==SQLITE_IOERR_NOMEM ){
2961       rc = SQLITE_NOMEM_BKPT;
2962     }
2963     sqlite3Error(db, rc);
2964     goto opendb_out;
2965   }
2966   sqlite3BtreeEnter(db->aDb[0].pBt);
2967   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2968   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2969   sqlite3BtreeLeave(db->aDb[0].pBt);
2970   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2971 
2972   /* The default safety_level for the main database is FULL; for the temp
2973   ** database it is OFF. This matches the pager layer defaults.
2974   */
2975   db->aDb[0].zDbSName = "main";
2976   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
2977   db->aDb[1].zDbSName = "temp";
2978   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
2979 
2980   db->magic = SQLITE_MAGIC_OPEN;
2981   if( db->mallocFailed ){
2982     goto opendb_out;
2983   }
2984 
2985   /* Register all built-in functions, but do not attempt to read the
2986   ** database schema yet. This is delayed until the first time the database
2987   ** is accessed.
2988   */
2989   sqlite3Error(db, SQLITE_OK);
2990   sqlite3RegisterPerConnectionBuiltinFunctions(db);
2991   rc = sqlite3_errcode(db);
2992 
2993 #ifdef SQLITE_ENABLE_FTS5
2994   /* Register any built-in FTS5 module before loading the automatic
2995   ** extensions. This allows automatic extensions to register FTS5
2996   ** tokenizers and auxiliary functions.  */
2997   if( !db->mallocFailed && rc==SQLITE_OK ){
2998     rc = sqlite3Fts5Init(db);
2999   }
3000 #endif
3001 
3002   /* Load automatic extensions - extensions that have been registered
3003   ** using the sqlite3_automatic_extension() API.
3004   */
3005   if( rc==SQLITE_OK ){
3006     sqlite3AutoLoadExtensions(db);
3007     rc = sqlite3_errcode(db);
3008     if( rc!=SQLITE_OK ){
3009       goto opendb_out;
3010     }
3011   }
3012 
3013 #ifdef SQLITE_ENABLE_FTS1
3014   if( !db->mallocFailed ){
3015     extern int sqlite3Fts1Init(sqlite3*);
3016     rc = sqlite3Fts1Init(db);
3017   }
3018 #endif
3019 
3020 #ifdef SQLITE_ENABLE_FTS2
3021   if( !db->mallocFailed && rc==SQLITE_OK ){
3022     extern int sqlite3Fts2Init(sqlite3*);
3023     rc = sqlite3Fts2Init(db);
3024   }
3025 #endif
3026 
3027 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3028   if( !db->mallocFailed && rc==SQLITE_OK ){
3029     rc = sqlite3Fts3Init(db);
3030   }
3031 #endif
3032 
3033 #ifdef SQLITE_ENABLE_ICU
3034   if( !db->mallocFailed && rc==SQLITE_OK ){
3035     rc = sqlite3IcuInit(db);
3036   }
3037 #endif
3038 
3039 #ifdef SQLITE_ENABLE_RTREE
3040   if( !db->mallocFailed && rc==SQLITE_OK){
3041     rc = sqlite3RtreeInit(db);
3042   }
3043 #endif
3044 
3045 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3046   if( !db->mallocFailed && rc==SQLITE_OK){
3047     rc = sqlite3DbstatRegister(db);
3048   }
3049 #endif
3050 
3051 #ifdef SQLITE_ENABLE_JSON1
3052   if( !db->mallocFailed && rc==SQLITE_OK){
3053     rc = sqlite3Json1Init(db);
3054   }
3055 #endif
3056 
3057   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3058   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3059   ** mode.  Doing nothing at all also makes NORMAL the default.
3060   */
3061 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3062   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3063   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3064                           SQLITE_DEFAULT_LOCKING_MODE);
3065 #endif
3066 
3067   if( rc ) sqlite3Error(db, rc);
3068 
3069   /* Enable the lookaside-malloc subsystem */
3070   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3071                         sqlite3GlobalConfig.nLookaside);
3072 
3073   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3074 
3075 opendb_out:
3076   if( db ){
3077     assert( db->mutex!=0 || isThreadsafe==0
3078            || sqlite3GlobalConfig.bFullMutex==0 );
3079     sqlite3_mutex_leave(db->mutex);
3080   }
3081   rc = sqlite3_errcode(db);
3082   assert( db!=0 || rc==SQLITE_NOMEM );
3083   if( rc==SQLITE_NOMEM ){
3084     sqlite3_close(db);
3085     db = 0;
3086   }else if( rc!=SQLITE_OK ){
3087     db->magic = SQLITE_MAGIC_SICK;
3088   }
3089   *ppDb = db;
3090 #ifdef SQLITE_ENABLE_SQLLOG
3091   if( sqlite3GlobalConfig.xSqllog ){
3092     /* Opening a db handle. Fourth parameter is passed 0. */
3093     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3094     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3095   }
3096 #endif
3097 #if defined(SQLITE_HAS_CODEC)
3098   if( rc==SQLITE_OK ){
3099     const char *zKey;
3100     if( (zKey = sqlite3_uri_parameter(zOpen, "hexkey"))!=0 && zKey[0] ){
3101       u8 iByte;
3102       int i;
3103       char zDecoded[40];
3104       for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
3105         iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
3106         if( (i&1)!=0 ) zDecoded[i/2] = iByte;
3107       }
3108       sqlite3_key_v2(db, 0, zDecoded, i/2);
3109     }else if( (zKey = sqlite3_uri_parameter(zOpen, "key"))!=0 ){
3110       sqlite3_key_v2(db, 0, zKey, sqlite3Strlen30(zKey));
3111     }
3112   }
3113 #endif
3114   sqlite3_free(zOpen);
3115   return rc & 0xff;
3116 }
3117 
3118 /*
3119 ** Open a new database handle.
3120 */
3121 int sqlite3_open(
3122   const char *zFilename,
3123   sqlite3 **ppDb
3124 ){
3125   return openDatabase(zFilename, ppDb,
3126                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3127 }
3128 int sqlite3_open_v2(
3129   const char *filename,   /* Database filename (UTF-8) */
3130   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3131   int flags,              /* Flags */
3132   const char *zVfs        /* Name of VFS module to use */
3133 ){
3134   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3135 }
3136 
3137 #ifndef SQLITE_OMIT_UTF16
3138 /*
3139 ** Open a new database handle.
3140 */
3141 int sqlite3_open16(
3142   const void *zFilename,
3143   sqlite3 **ppDb
3144 ){
3145   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3146   sqlite3_value *pVal;
3147   int rc;
3148 
3149 #ifdef SQLITE_ENABLE_API_ARMOR
3150   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3151 #endif
3152   *ppDb = 0;
3153 #ifndef SQLITE_OMIT_AUTOINIT
3154   rc = sqlite3_initialize();
3155   if( rc ) return rc;
3156 #endif
3157   if( zFilename==0 ) zFilename = "\000\000";
3158   pVal = sqlite3ValueNew(0);
3159   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3160   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3161   if( zFilename8 ){
3162     rc = openDatabase(zFilename8, ppDb,
3163                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3164     assert( *ppDb || rc==SQLITE_NOMEM );
3165     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3166       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3167     }
3168   }else{
3169     rc = SQLITE_NOMEM_BKPT;
3170   }
3171   sqlite3ValueFree(pVal);
3172 
3173   return rc & 0xff;
3174 }
3175 #endif /* SQLITE_OMIT_UTF16 */
3176 
3177 /*
3178 ** Register a new collation sequence with the database handle db.
3179 */
3180 int sqlite3_create_collation(
3181   sqlite3* db,
3182   const char *zName,
3183   int enc,
3184   void* pCtx,
3185   int(*xCompare)(void*,int,const void*,int,const void*)
3186 ){
3187   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3188 }
3189 
3190 /*
3191 ** Register a new collation sequence with the database handle db.
3192 */
3193 int sqlite3_create_collation_v2(
3194   sqlite3* db,
3195   const char *zName,
3196   int enc,
3197   void* pCtx,
3198   int(*xCompare)(void*,int,const void*,int,const void*),
3199   void(*xDel)(void*)
3200 ){
3201   int rc;
3202 
3203 #ifdef SQLITE_ENABLE_API_ARMOR
3204   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3205 #endif
3206   sqlite3_mutex_enter(db->mutex);
3207   assert( !db->mallocFailed );
3208   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3209   rc = sqlite3ApiExit(db, rc);
3210   sqlite3_mutex_leave(db->mutex);
3211   return rc;
3212 }
3213 
3214 #ifndef SQLITE_OMIT_UTF16
3215 /*
3216 ** Register a new collation sequence with the database handle db.
3217 */
3218 int sqlite3_create_collation16(
3219   sqlite3* db,
3220   const void *zName,
3221   int enc,
3222   void* pCtx,
3223   int(*xCompare)(void*,int,const void*,int,const void*)
3224 ){
3225   int rc = SQLITE_OK;
3226   char *zName8;
3227 
3228 #ifdef SQLITE_ENABLE_API_ARMOR
3229   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3230 #endif
3231   sqlite3_mutex_enter(db->mutex);
3232   assert( !db->mallocFailed );
3233   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3234   if( zName8 ){
3235     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3236     sqlite3DbFree(db, zName8);
3237   }
3238   rc = sqlite3ApiExit(db, rc);
3239   sqlite3_mutex_leave(db->mutex);
3240   return rc;
3241 }
3242 #endif /* SQLITE_OMIT_UTF16 */
3243 
3244 /*
3245 ** Register a collation sequence factory callback with the database handle
3246 ** db. Replace any previously installed collation sequence factory.
3247 */
3248 int sqlite3_collation_needed(
3249   sqlite3 *db,
3250   void *pCollNeededArg,
3251   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3252 ){
3253 #ifdef SQLITE_ENABLE_API_ARMOR
3254   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3255 #endif
3256   sqlite3_mutex_enter(db->mutex);
3257   db->xCollNeeded = xCollNeeded;
3258   db->xCollNeeded16 = 0;
3259   db->pCollNeededArg = pCollNeededArg;
3260   sqlite3_mutex_leave(db->mutex);
3261   return SQLITE_OK;
3262 }
3263 
3264 #ifndef SQLITE_OMIT_UTF16
3265 /*
3266 ** Register a collation sequence factory callback with the database handle
3267 ** db. Replace any previously installed collation sequence factory.
3268 */
3269 int sqlite3_collation_needed16(
3270   sqlite3 *db,
3271   void *pCollNeededArg,
3272   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3273 ){
3274 #ifdef SQLITE_ENABLE_API_ARMOR
3275   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3276 #endif
3277   sqlite3_mutex_enter(db->mutex);
3278   db->xCollNeeded = 0;
3279   db->xCollNeeded16 = xCollNeeded16;
3280   db->pCollNeededArg = pCollNeededArg;
3281   sqlite3_mutex_leave(db->mutex);
3282   return SQLITE_OK;
3283 }
3284 #endif /* SQLITE_OMIT_UTF16 */
3285 
3286 #ifndef SQLITE_OMIT_DEPRECATED
3287 /*
3288 ** This function is now an anachronism. It used to be used to recover from a
3289 ** malloc() failure, but SQLite now does this automatically.
3290 */
3291 int sqlite3_global_recover(void){
3292   return SQLITE_OK;
3293 }
3294 #endif
3295 
3296 /*
3297 ** Test to see whether or not the database connection is in autocommit
3298 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3299 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3300 ** by the next COMMIT or ROLLBACK.
3301 */
3302 int sqlite3_get_autocommit(sqlite3 *db){
3303 #ifdef SQLITE_ENABLE_API_ARMOR
3304   if( !sqlite3SafetyCheckOk(db) ){
3305     (void)SQLITE_MISUSE_BKPT;
3306     return 0;
3307   }
3308 #endif
3309   return db->autoCommit;
3310 }
3311 
3312 /*
3313 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3314 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3315 ** constants.  They serve two purposes:
3316 **
3317 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3318 **       to detect when version error conditions occurs.
3319 **
3320 **   2.  Invoke sqlite3_log() to provide the source code location where
3321 **       a low-level error is first detected.
3322 */
3323 static int reportError(int iErr, int lineno, const char *zType){
3324   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3325               zType, lineno, 20+sqlite3_sourceid());
3326   return iErr;
3327 }
3328 int sqlite3CorruptError(int lineno){
3329   testcase( sqlite3GlobalConfig.xLog!=0 );
3330   return reportError(SQLITE_CORRUPT, lineno, "database corruption");
3331 }
3332 int sqlite3MisuseError(int lineno){
3333   testcase( sqlite3GlobalConfig.xLog!=0 );
3334   return reportError(SQLITE_MISUSE, lineno, "misuse");
3335 }
3336 int sqlite3CantopenError(int lineno){
3337   testcase( sqlite3GlobalConfig.xLog!=0 );
3338   return reportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3339 }
3340 #ifdef SQLITE_DEBUG
3341 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3342   char zMsg[100];
3343   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3344   testcase( sqlite3GlobalConfig.xLog!=0 );
3345   return reportError(SQLITE_CORRUPT, lineno, zMsg);
3346 }
3347 int sqlite3NomemError(int lineno){
3348   testcase( sqlite3GlobalConfig.xLog!=0 );
3349   return reportError(SQLITE_NOMEM, lineno, "OOM");
3350 }
3351 int sqlite3IoerrnomemError(int lineno){
3352   testcase( sqlite3GlobalConfig.xLog!=0 );
3353   return reportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3354 }
3355 #endif
3356 
3357 #ifndef SQLITE_OMIT_DEPRECATED
3358 /*
3359 ** This is a convenience routine that makes sure that all thread-specific
3360 ** data for this thread has been deallocated.
3361 **
3362 ** SQLite no longer uses thread-specific data so this routine is now a
3363 ** no-op.  It is retained for historical compatibility.
3364 */
3365 void sqlite3_thread_cleanup(void){
3366 }
3367 #endif
3368 
3369 /*
3370 ** Return meta information about a specific column of a database table.
3371 ** See comment in sqlite3.h (sqlite.h.in) for details.
3372 */
3373 int sqlite3_table_column_metadata(
3374   sqlite3 *db,                /* Connection handle */
3375   const char *zDbName,        /* Database name or NULL */
3376   const char *zTableName,     /* Table name */
3377   const char *zColumnName,    /* Column name */
3378   char const **pzDataType,    /* OUTPUT: Declared data type */
3379   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3380   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3381   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3382   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3383 ){
3384   int rc;
3385   char *zErrMsg = 0;
3386   Table *pTab = 0;
3387   Column *pCol = 0;
3388   int iCol = 0;
3389   char const *zDataType = 0;
3390   char const *zCollSeq = 0;
3391   int notnull = 0;
3392   int primarykey = 0;
3393   int autoinc = 0;
3394 
3395 
3396 #ifdef SQLITE_ENABLE_API_ARMOR
3397   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3398     return SQLITE_MISUSE_BKPT;
3399   }
3400 #endif
3401 
3402   /* Ensure the database schema has been loaded */
3403   sqlite3_mutex_enter(db->mutex);
3404   sqlite3BtreeEnterAll(db);
3405   rc = sqlite3Init(db, &zErrMsg);
3406   if( SQLITE_OK!=rc ){
3407     goto error_out;
3408   }
3409 
3410   /* Locate the table in question */
3411   pTab = sqlite3FindTable(db, zTableName, zDbName);
3412   if( !pTab || pTab->pSelect ){
3413     pTab = 0;
3414     goto error_out;
3415   }
3416 
3417   /* Find the column for which info is requested */
3418   if( zColumnName==0 ){
3419     /* Query for existance of table only */
3420   }else{
3421     for(iCol=0; iCol<pTab->nCol; iCol++){
3422       pCol = &pTab->aCol[iCol];
3423       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3424         break;
3425       }
3426     }
3427     if( iCol==pTab->nCol ){
3428       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3429         iCol = pTab->iPKey;
3430         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3431       }else{
3432         pTab = 0;
3433         goto error_out;
3434       }
3435     }
3436   }
3437 
3438   /* The following block stores the meta information that will be returned
3439   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3440   ** and autoinc. At this point there are two possibilities:
3441   **
3442   **     1. The specified column name was rowid", "oid" or "_rowid_"
3443   **        and there is no explicitly declared IPK column.
3444   **
3445   **     2. The table is not a view and the column name identified an
3446   **        explicitly declared column. Copy meta information from *pCol.
3447   */
3448   if( pCol ){
3449     zDataType = sqlite3ColumnType(pCol,0);
3450     zCollSeq = pCol->zColl;
3451     notnull = pCol->notNull!=0;
3452     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3453     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3454   }else{
3455     zDataType = "INTEGER";
3456     primarykey = 1;
3457   }
3458   if( !zCollSeq ){
3459     zCollSeq = sqlite3StrBINARY;
3460   }
3461 
3462 error_out:
3463   sqlite3BtreeLeaveAll(db);
3464 
3465   /* Whether the function call succeeded or failed, set the output parameters
3466   ** to whatever their local counterparts contain. If an error did occur,
3467   ** this has the effect of zeroing all output parameters.
3468   */
3469   if( pzDataType ) *pzDataType = zDataType;
3470   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3471   if( pNotNull ) *pNotNull = notnull;
3472   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3473   if( pAutoinc ) *pAutoinc = autoinc;
3474 
3475   if( SQLITE_OK==rc && !pTab ){
3476     sqlite3DbFree(db, zErrMsg);
3477     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3478         zColumnName);
3479     rc = SQLITE_ERROR;
3480   }
3481   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3482   sqlite3DbFree(db, zErrMsg);
3483   rc = sqlite3ApiExit(db, rc);
3484   sqlite3_mutex_leave(db->mutex);
3485   return rc;
3486 }
3487 
3488 /*
3489 ** Sleep for a little while.  Return the amount of time slept.
3490 */
3491 int sqlite3_sleep(int ms){
3492   sqlite3_vfs *pVfs;
3493   int rc;
3494   pVfs = sqlite3_vfs_find(0);
3495   if( pVfs==0 ) return 0;
3496 
3497   /* This function works in milliseconds, but the underlying OsSleep()
3498   ** API uses microseconds. Hence the 1000's.
3499   */
3500   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3501   return rc;
3502 }
3503 
3504 /*
3505 ** Enable or disable the extended result codes.
3506 */
3507 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3508 #ifdef SQLITE_ENABLE_API_ARMOR
3509   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3510 #endif
3511   sqlite3_mutex_enter(db->mutex);
3512   db->errMask = onoff ? 0xffffffff : 0xff;
3513   sqlite3_mutex_leave(db->mutex);
3514   return SQLITE_OK;
3515 }
3516 
3517 /*
3518 ** Invoke the xFileControl method on a particular database.
3519 */
3520 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3521   int rc = SQLITE_ERROR;
3522   Btree *pBtree;
3523 
3524 #ifdef SQLITE_ENABLE_API_ARMOR
3525   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3526 #endif
3527   sqlite3_mutex_enter(db->mutex);
3528   pBtree = sqlite3DbNameToBtree(db, zDbName);
3529   if( pBtree ){
3530     Pager *pPager;
3531     sqlite3_file *fd;
3532     sqlite3BtreeEnter(pBtree);
3533     pPager = sqlite3BtreePager(pBtree);
3534     assert( pPager!=0 );
3535     fd = sqlite3PagerFile(pPager);
3536     assert( fd!=0 );
3537     if( op==SQLITE_FCNTL_FILE_POINTER ){
3538       *(sqlite3_file**)pArg = fd;
3539       rc = SQLITE_OK;
3540     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3541       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3542       rc = SQLITE_OK;
3543     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3544       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3545       rc = SQLITE_OK;
3546     }else if( fd->pMethods ){
3547       rc = sqlite3OsFileControl(fd, op, pArg);
3548     }else{
3549       rc = SQLITE_NOTFOUND;
3550     }
3551     sqlite3BtreeLeave(pBtree);
3552   }
3553   sqlite3_mutex_leave(db->mutex);
3554   return rc;
3555 }
3556 
3557 /*
3558 ** Interface to the testing logic.
3559 */
3560 int sqlite3_test_control(int op, ...){
3561   int rc = 0;
3562 #ifdef SQLITE_UNTESTABLE
3563   UNUSED_PARAMETER(op);
3564 #else
3565   va_list ap;
3566   va_start(ap, op);
3567   switch( op ){
3568 
3569     /*
3570     ** Save the current state of the PRNG.
3571     */
3572     case SQLITE_TESTCTRL_PRNG_SAVE: {
3573       sqlite3PrngSaveState();
3574       break;
3575     }
3576 
3577     /*
3578     ** Restore the state of the PRNG to the last state saved using
3579     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3580     ** this verb acts like PRNG_RESET.
3581     */
3582     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3583       sqlite3PrngRestoreState();
3584       break;
3585     }
3586 
3587     /*
3588     ** Reset the PRNG back to its uninitialized state.  The next call
3589     ** to sqlite3_randomness() will reseed the PRNG using a single call
3590     ** to the xRandomness method of the default VFS.
3591     */
3592     case SQLITE_TESTCTRL_PRNG_RESET: {
3593       sqlite3_randomness(0,0);
3594       break;
3595     }
3596 
3597     /*
3598     **  sqlite3_test_control(BITVEC_TEST, size, program)
3599     **
3600     ** Run a test against a Bitvec object of size.  The program argument
3601     ** is an array of integers that defines the test.  Return -1 on a
3602     ** memory allocation error, 0 on success, or non-zero for an error.
3603     ** See the sqlite3BitvecBuiltinTest() for additional information.
3604     */
3605     case SQLITE_TESTCTRL_BITVEC_TEST: {
3606       int sz = va_arg(ap, int);
3607       int *aProg = va_arg(ap, int*);
3608       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3609       break;
3610     }
3611 
3612     /*
3613     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3614     **
3615     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3616     ** if xCallback is not NULL.
3617     **
3618     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3619     ** is called immediately after installing the new callback and the return
3620     ** value from sqlite3FaultSim(0) becomes the return from
3621     ** sqlite3_test_control().
3622     */
3623     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3624       /* MSVC is picky about pulling func ptrs from va lists.
3625       ** http://support.microsoft.com/kb/47961
3626       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3627       */
3628       typedef int(*TESTCALLBACKFUNC_t)(int);
3629       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3630       rc = sqlite3FaultSim(0);
3631       break;
3632     }
3633 
3634     /*
3635     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3636     **
3637     ** Register hooks to call to indicate which malloc() failures
3638     ** are benign.
3639     */
3640     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3641       typedef void (*void_function)(void);
3642       void_function xBenignBegin;
3643       void_function xBenignEnd;
3644       xBenignBegin = va_arg(ap, void_function);
3645       xBenignEnd = va_arg(ap, void_function);
3646       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3647       break;
3648     }
3649 
3650     /*
3651     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3652     **
3653     ** Set the PENDING byte to the value in the argument, if X>0.
3654     ** Make no changes if X==0.  Return the value of the pending byte
3655     ** as it existing before this routine was called.
3656     **
3657     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3658     ** an incompatible database file format.  Changing the PENDING byte
3659     ** while any database connection is open results in undefined and
3660     ** deleterious behavior.
3661     */
3662     case SQLITE_TESTCTRL_PENDING_BYTE: {
3663       rc = PENDING_BYTE;
3664 #ifndef SQLITE_OMIT_WSD
3665       {
3666         unsigned int newVal = va_arg(ap, unsigned int);
3667         if( newVal ) sqlite3PendingByte = newVal;
3668       }
3669 #endif
3670       break;
3671     }
3672 
3673     /*
3674     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3675     **
3676     ** This action provides a run-time test to see whether or not
3677     ** assert() was enabled at compile-time.  If X is true and assert()
3678     ** is enabled, then the return value is true.  If X is true and
3679     ** assert() is disabled, then the return value is zero.  If X is
3680     ** false and assert() is enabled, then the assertion fires and the
3681     ** process aborts.  If X is false and assert() is disabled, then the
3682     ** return value is zero.
3683     */
3684     case SQLITE_TESTCTRL_ASSERT: {
3685       volatile int x = 0;
3686       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3687       rc = x;
3688       break;
3689     }
3690 
3691 
3692     /*
3693     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3694     **
3695     ** This action provides a run-time test to see how the ALWAYS and
3696     ** NEVER macros were defined at compile-time.
3697     **
3698     ** The return value is ALWAYS(X).
3699     **
3700     ** The recommended test is X==2.  If the return value is 2, that means
3701     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3702     ** default setting.  If the return value is 1, then ALWAYS() is either
3703     ** hard-coded to true or else it asserts if its argument is false.
3704     ** The first behavior (hard-coded to true) is the case if
3705     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3706     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3707     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3708     **
3709     ** The run-time test procedure might look something like this:
3710     **
3711     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3712     **      // ALWAYS() and NEVER() are no-op pass-through macros
3713     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3714     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3715     **    }else{
3716     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3717     **    }
3718     */
3719     case SQLITE_TESTCTRL_ALWAYS: {
3720       int x = va_arg(ap,int);
3721       rc = ALWAYS(x);
3722       break;
3723     }
3724 
3725     /*
3726     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3727     **
3728     ** The integer returned reveals the byte-order of the computer on which
3729     ** SQLite is running:
3730     **
3731     **       1     big-endian,    determined at run-time
3732     **      10     little-endian, determined at run-time
3733     **  432101     big-endian,    determined at compile-time
3734     **  123410     little-endian, determined at compile-time
3735     */
3736     case SQLITE_TESTCTRL_BYTEORDER: {
3737       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3738       break;
3739     }
3740 
3741     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3742     **
3743     ** Set the nReserve size to N for the main database on the database
3744     ** connection db.
3745     */
3746     case SQLITE_TESTCTRL_RESERVE: {
3747       sqlite3 *db = va_arg(ap, sqlite3*);
3748       int x = va_arg(ap,int);
3749       sqlite3_mutex_enter(db->mutex);
3750       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3751       sqlite3_mutex_leave(db->mutex);
3752       break;
3753     }
3754 
3755     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3756     **
3757     ** Enable or disable various optimizations for testing purposes.  The
3758     ** argument N is a bitmask of optimizations to be disabled.  For normal
3759     ** operation N should be 0.  The idea is that a test program (like the
3760     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3761     ** with various optimizations disabled to verify that the same answer
3762     ** is obtained in every case.
3763     */
3764     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3765       sqlite3 *db = va_arg(ap, sqlite3*);
3766       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3767       break;
3768     }
3769 
3770 #ifdef SQLITE_N_KEYWORD
3771     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3772     **
3773     ** If zWord is a keyword recognized by the parser, then return the
3774     ** number of keywords.  Or if zWord is not a keyword, return 0.
3775     **
3776     ** This test feature is only available in the amalgamation since
3777     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3778     ** is built using separate source files.
3779     */
3780     case SQLITE_TESTCTRL_ISKEYWORD: {
3781       const char *zWord = va_arg(ap, const char*);
3782       int n = sqlite3Strlen30(zWord);
3783       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3784       break;
3785     }
3786 #endif
3787 
3788     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3789     **
3790     ** Pass pFree into sqlite3ScratchFree().
3791     ** If sz>0 then allocate a scratch buffer into pNew.
3792     */
3793     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3794       void *pFree, **ppNew;
3795       int sz;
3796       sz = va_arg(ap, int);
3797       ppNew = va_arg(ap, void**);
3798       pFree = va_arg(ap, void*);
3799       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3800       sqlite3ScratchFree(pFree);
3801       break;
3802     }
3803 
3804     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3805     **
3806     ** If parameter onoff is non-zero, configure the wrappers so that all
3807     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3808     ** undo this setting.
3809     */
3810     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3811       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3812       break;
3813     }
3814 
3815     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3816     **
3817     ** Set or clear a flag that indicates that the database file is always well-
3818     ** formed and never corrupt.  This flag is clear by default, indicating that
3819     ** database files might have arbitrary corruption.  Setting the flag during
3820     ** testing causes certain assert() statements in the code to be activated
3821     ** that demonstrat invariants on well-formed database files.
3822     */
3823     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3824       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3825       break;
3826     }
3827 
3828     /* Set the threshold at which OP_Once counters reset back to zero.
3829     ** By default this is 0x7ffffffe (over 2 billion), but that value is
3830     ** too big to test in a reasonable amount of time, so this control is
3831     ** provided to set a small and easily reachable reset value.
3832     */
3833     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
3834       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
3835       break;
3836     }
3837 
3838     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3839     **
3840     ** Set the VDBE coverage callback function to xCallback with context
3841     ** pointer ptr.
3842     */
3843     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3844 #ifdef SQLITE_VDBE_COVERAGE
3845       typedef void (*branch_callback)(void*,int,u8,u8);
3846       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3847       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3848 #endif
3849       break;
3850     }
3851 
3852     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3853     case SQLITE_TESTCTRL_SORTER_MMAP: {
3854       sqlite3 *db = va_arg(ap, sqlite3*);
3855       db->nMaxSorterMmap = va_arg(ap, int);
3856       break;
3857     }
3858 
3859     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3860     **
3861     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3862     ** not.
3863     */
3864     case SQLITE_TESTCTRL_ISINIT: {
3865       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3866       break;
3867     }
3868 
3869     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3870     **
3871     ** This test control is used to create imposter tables.  "db" is a pointer
3872     ** to the database connection.  dbName is the database name (ex: "main" or
3873     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3874     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3875     ** table should connect.
3876     **
3877     ** Enable imposter mode only when the schema has already been parsed.  Then
3878     ** run a single CREATE TABLE statement to construct the imposter table in
3879     ** the parsed schema.  Then turn imposter mode back off again.
3880     **
3881     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3882     ** the schema to be reparsed the next time it is needed.  This has the
3883     ** effect of erasing all imposter tables.
3884     */
3885     case SQLITE_TESTCTRL_IMPOSTER: {
3886       sqlite3 *db = va_arg(ap, sqlite3*);
3887       sqlite3_mutex_enter(db->mutex);
3888       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3889       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3890       db->init.newTnum = va_arg(ap,int);
3891       if( db->init.busy==0 && db->init.newTnum>0 ){
3892         sqlite3ResetAllSchemasOfConnection(db);
3893       }
3894       sqlite3_mutex_leave(db->mutex);
3895       break;
3896     }
3897   }
3898   va_end(ap);
3899 #endif /* SQLITE_UNTESTABLE */
3900   return rc;
3901 }
3902 
3903 /*
3904 ** This is a utility routine, useful to VFS implementations, that checks
3905 ** to see if a database file was a URI that contained a specific query
3906 ** parameter, and if so obtains the value of the query parameter.
3907 **
3908 ** The zFilename argument is the filename pointer passed into the xOpen()
3909 ** method of a VFS implementation.  The zParam argument is the name of the
3910 ** query parameter we seek.  This routine returns the value of the zParam
3911 ** parameter if it exists.  If the parameter does not exist, this routine
3912 ** returns a NULL pointer.
3913 */
3914 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3915   if( zFilename==0 || zParam==0 ) return 0;
3916   zFilename += sqlite3Strlen30(zFilename) + 1;
3917   while( zFilename[0] ){
3918     int x = strcmp(zFilename, zParam);
3919     zFilename += sqlite3Strlen30(zFilename) + 1;
3920     if( x==0 ) return zFilename;
3921     zFilename += sqlite3Strlen30(zFilename) + 1;
3922   }
3923   return 0;
3924 }
3925 
3926 /*
3927 ** Return a boolean value for a query parameter.
3928 */
3929 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3930   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3931   bDflt = bDflt!=0;
3932   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3933 }
3934 
3935 /*
3936 ** Return a 64-bit integer value for a query parameter.
3937 */
3938 sqlite3_int64 sqlite3_uri_int64(
3939   const char *zFilename,    /* Filename as passed to xOpen */
3940   const char *zParam,       /* URI parameter sought */
3941   sqlite3_int64 bDflt       /* return if parameter is missing */
3942 ){
3943   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3944   sqlite3_int64 v;
3945   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3946     bDflt = v;
3947   }
3948   return bDflt;
3949 }
3950 
3951 /*
3952 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3953 */
3954 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3955   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
3956   return iDb<0 ? 0 : db->aDb[iDb].pBt;
3957 }
3958 
3959 /*
3960 ** Return the filename of the database associated with a database
3961 ** connection.
3962 */
3963 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3964   Btree *pBt;
3965 #ifdef SQLITE_ENABLE_API_ARMOR
3966   if( !sqlite3SafetyCheckOk(db) ){
3967     (void)SQLITE_MISUSE_BKPT;
3968     return 0;
3969   }
3970 #endif
3971   pBt = sqlite3DbNameToBtree(db, zDbName);
3972   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3973 }
3974 
3975 /*
3976 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3977 ** no such database exists.
3978 */
3979 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3980   Btree *pBt;
3981 #ifdef SQLITE_ENABLE_API_ARMOR
3982   if( !sqlite3SafetyCheckOk(db) ){
3983     (void)SQLITE_MISUSE_BKPT;
3984     return -1;
3985   }
3986 #endif
3987   pBt = sqlite3DbNameToBtree(db, zDbName);
3988   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3989 }
3990 
3991 #ifdef SQLITE_ENABLE_SNAPSHOT
3992 /*
3993 ** Obtain a snapshot handle for the snapshot of database zDb currently
3994 ** being read by handle db.
3995 */
3996 int sqlite3_snapshot_get(
3997   sqlite3 *db,
3998   const char *zDb,
3999   sqlite3_snapshot **ppSnapshot
4000 ){
4001   int rc = SQLITE_ERROR;
4002 #ifndef SQLITE_OMIT_WAL
4003 
4004 #ifdef SQLITE_ENABLE_API_ARMOR
4005   if( !sqlite3SafetyCheckOk(db) ){
4006     return SQLITE_MISUSE_BKPT;
4007   }
4008 #endif
4009   sqlite3_mutex_enter(db->mutex);
4010 
4011   if( db->autoCommit==0 ){
4012     int iDb = sqlite3FindDbName(db, zDb);
4013     if( iDb==0 || iDb>1 ){
4014       Btree *pBt = db->aDb[iDb].pBt;
4015       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4016         rc = sqlite3BtreeBeginTrans(pBt, 0);
4017         if( rc==SQLITE_OK ){
4018           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4019         }
4020       }
4021     }
4022   }
4023 
4024   sqlite3_mutex_leave(db->mutex);
4025 #endif   /* SQLITE_OMIT_WAL */
4026   return rc;
4027 }
4028 
4029 /*
4030 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4031 */
4032 int sqlite3_snapshot_open(
4033   sqlite3 *db,
4034   const char *zDb,
4035   sqlite3_snapshot *pSnapshot
4036 ){
4037   int rc = SQLITE_ERROR;
4038 #ifndef SQLITE_OMIT_WAL
4039 
4040 #ifdef SQLITE_ENABLE_API_ARMOR
4041   if( !sqlite3SafetyCheckOk(db) ){
4042     return SQLITE_MISUSE_BKPT;
4043   }
4044 #endif
4045   sqlite3_mutex_enter(db->mutex);
4046   if( db->autoCommit==0 ){
4047     int iDb;
4048     iDb = sqlite3FindDbName(db, zDb);
4049     if( iDb==0 || iDb>1 ){
4050       Btree *pBt = db->aDb[iDb].pBt;
4051       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4052         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
4053         if( rc==SQLITE_OK ){
4054           rc = sqlite3BtreeBeginTrans(pBt, 0);
4055           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
4056         }
4057       }
4058     }
4059   }
4060 
4061   sqlite3_mutex_leave(db->mutex);
4062 #endif   /* SQLITE_OMIT_WAL */
4063   return rc;
4064 }
4065 
4066 /*
4067 ** Recover as many snapshots as possible from the wal file associated with
4068 ** schema zDb of database db.
4069 */
4070 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4071   int rc = SQLITE_ERROR;
4072   int iDb;
4073 #ifndef SQLITE_OMIT_WAL
4074 
4075 #ifdef SQLITE_ENABLE_API_ARMOR
4076   if( !sqlite3SafetyCheckOk(db) ){
4077     return SQLITE_MISUSE_BKPT;
4078   }
4079 #endif
4080 
4081   sqlite3_mutex_enter(db->mutex);
4082   iDb = sqlite3FindDbName(db, zDb);
4083   if( iDb==0 || iDb>1 ){
4084     Btree *pBt = db->aDb[iDb].pBt;
4085     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4086       rc = sqlite3BtreeBeginTrans(pBt, 0);
4087       if( rc==SQLITE_OK ){
4088         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4089         sqlite3BtreeCommit(pBt);
4090       }
4091     }
4092   }
4093   sqlite3_mutex_leave(db->mutex);
4094 #endif   /* SQLITE_OMIT_WAL */
4095   return rc;
4096 }
4097 
4098 /*
4099 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4100 */
4101 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4102   sqlite3_free(pSnapshot);
4103 }
4104 #endif /* SQLITE_ENABLE_SNAPSHOT */
4105