xref: /sqlite-3.40.0/src/main.c (revision cd423525)
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;
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     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
222     sqlite3GlobalConfig.inProgress = 1;
223 #ifdef SQLITE_ENABLE_SQLLOG
224     {
225       extern void sqlite3_init_sqllog(void);
226       sqlite3_init_sqllog();
227     }
228 #endif
229     memset(pHash, 0, sizeof(sqlite3GlobalFunctions));
230     sqlite3RegisterGlobalFunctions();
231     if( sqlite3GlobalConfig.isPCacheInit==0 ){
232       rc = sqlite3PcacheInitialize();
233     }
234     if( rc==SQLITE_OK ){
235       sqlite3GlobalConfig.isPCacheInit = 1;
236       rc = sqlite3OsInit();
237     }
238     if( rc==SQLITE_OK ){
239       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
240           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
241       sqlite3GlobalConfig.isInit = 1;
242 #ifdef SQLITE_EXTRA_INIT
243       bRunExtraInit = 1;
244 #endif
245     }
246     sqlite3GlobalConfig.inProgress = 0;
247   }
248   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
249 
250   /* Go back under the static mutex and clean up the recursive
251   ** mutex to prevent a resource leak.
252   */
253   sqlite3_mutex_enter(pMaster);
254   sqlite3GlobalConfig.nRefInitMutex--;
255   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
256     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
257     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
258     sqlite3GlobalConfig.pInitMutex = 0;
259   }
260   sqlite3_mutex_leave(pMaster);
261 
262   /* The following is just a sanity check to make sure SQLite has
263   ** been compiled correctly.  It is important to run this code, but
264   ** we don't want to run it too often and soak up CPU cycles for no
265   ** reason.  So we run it once during initialization.
266   */
267 #ifndef NDEBUG
268 #ifndef SQLITE_OMIT_FLOATING_POINT
269   /* This section of code's only "output" is via assert() statements. */
270   if ( rc==SQLITE_OK ){
271     u64 x = (((u64)1)<<63)-1;
272     double y;
273     assert(sizeof(x)==8);
274     assert(sizeof(x)==sizeof(y));
275     memcpy(&y, &x, 8);
276     assert( sqlite3IsNaN(y) );
277   }
278 #endif
279 #endif
280 
281   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
282   ** compile-time option.
283   */
284 #ifdef SQLITE_EXTRA_INIT
285   if( bRunExtraInit ){
286     int SQLITE_EXTRA_INIT(const char*);
287     rc = SQLITE_EXTRA_INIT(0);
288   }
289 #endif
290 
291   return rc;
292 }
293 
294 /*
295 ** Undo the effects of sqlite3_initialize().  Must not be called while
296 ** there are outstanding database connections or memory allocations or
297 ** while any part of SQLite is otherwise in use in any thread.  This
298 ** routine is not threadsafe.  But it is safe to invoke this routine
299 ** on when SQLite is already shut down.  If SQLite is already shut down
300 ** when this routine is invoked, then this routine is a harmless no-op.
301 */
302 int sqlite3_shutdown(void){
303 #ifdef SQLITE_OMIT_WSD
304   int rc = sqlite3_wsd_init(4096, 24);
305   if( rc!=SQLITE_OK ){
306     return rc;
307   }
308 #endif
309 
310   if( sqlite3GlobalConfig.isInit ){
311 #ifdef SQLITE_EXTRA_SHUTDOWN
312     void SQLITE_EXTRA_SHUTDOWN(void);
313     SQLITE_EXTRA_SHUTDOWN();
314 #endif
315     sqlite3_os_end();
316     sqlite3_reset_auto_extension();
317     sqlite3GlobalConfig.isInit = 0;
318   }
319   if( sqlite3GlobalConfig.isPCacheInit ){
320     sqlite3PcacheShutdown();
321     sqlite3GlobalConfig.isPCacheInit = 0;
322   }
323   if( sqlite3GlobalConfig.isMallocInit ){
324     sqlite3MallocEnd();
325     sqlite3GlobalConfig.isMallocInit = 0;
326 
327 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
328     /* The heap subsystem has now been shutdown and these values are supposed
329     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
330     ** which would rely on that heap subsystem; therefore, make sure these
331     ** values cannot refer to heap memory that was just invalidated when the
332     ** heap subsystem was shutdown.  This is only done if the current call to
333     ** this function resulted in the heap subsystem actually being shutdown.
334     */
335     sqlite3_data_directory = 0;
336     sqlite3_temp_directory = 0;
337 #endif
338   }
339   if( sqlite3GlobalConfig.isMutexInit ){
340     sqlite3MutexEnd();
341     sqlite3GlobalConfig.isMutexInit = 0;
342   }
343 
344   return SQLITE_OK;
345 }
346 
347 /*
348 ** This API allows applications to modify the global configuration of
349 ** the SQLite library at run-time.
350 **
351 ** This routine should only be called when there are no outstanding
352 ** database connections or memory allocations.  This routine is not
353 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
354 ** behavior.
355 */
356 int sqlite3_config(int op, ...){
357   va_list ap;
358   int rc = SQLITE_OK;
359 
360   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
361   ** the SQLite library is in use. */
362   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
363 
364   va_start(ap, op);
365   switch( op ){
366 
367     /* Mutex configuration options are only available in a threadsafe
368     ** compile.
369     */
370 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
371     case SQLITE_CONFIG_SINGLETHREAD: {
372       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
373       ** Single-thread. */
374       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
375       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
376       break;
377     }
378 #endif
379 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
380     case SQLITE_CONFIG_MULTITHREAD: {
381       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
382       ** Multi-thread. */
383       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
384       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
385       break;
386     }
387 #endif
388 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
389     case SQLITE_CONFIG_SERIALIZED: {
390       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
391       ** Serialized. */
392       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
393       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
394       break;
395     }
396 #endif
397 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
398     case SQLITE_CONFIG_MUTEX: {
399       /* Specify an alternative mutex implementation */
400       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
401       break;
402     }
403 #endif
404 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
405     case SQLITE_CONFIG_GETMUTEX: {
406       /* Retrieve the current mutex implementation */
407       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
408       break;
409     }
410 #endif
411 
412     case SQLITE_CONFIG_MALLOC: {
413       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
414       ** single argument which is a pointer to an instance of the
415       ** sqlite3_mem_methods structure. The argument specifies alternative
416       ** low-level memory allocation routines to be used in place of the memory
417       ** allocation routines built into SQLite. */
418       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
419       break;
420     }
421     case SQLITE_CONFIG_GETMALLOC: {
422       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
423       ** single argument which is a pointer to an instance of the
424       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
425       ** filled with the currently defined memory allocation routines. */
426       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
427       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
428       break;
429     }
430     case SQLITE_CONFIG_MEMSTATUS: {
431       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
432       ** single argument of type int, interpreted as a boolean, which enables
433       ** or disables the collection of memory allocation statistics. */
434       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
435       break;
436     }
437     case SQLITE_CONFIG_SCRATCH: {
438       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
439       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
440       ** which the scratch allocations will be drawn, the size of each scratch
441       ** allocation (sz), and the maximum number of scratch allocations (N). */
442       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
443       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
444       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
445       break;
446     }
447     case SQLITE_CONFIG_PAGECACHE: {
448       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
449       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
450       ** the size of each page cache line (sz), and the number of cache lines
451       ** (N). */
452       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
453       sqlite3GlobalConfig.szPage = va_arg(ap, int);
454       sqlite3GlobalConfig.nPage = va_arg(ap, int);
455       break;
456     }
457     case SQLITE_CONFIG_PCACHE_HDRSZ: {
458       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
459       ** a single parameter which is a pointer to an integer and writes into
460       ** that integer the number of extra bytes per page required for each page
461       ** in SQLITE_CONFIG_PAGECACHE. */
462       *va_arg(ap, int*) =
463           sqlite3HeaderSizeBtree() +
464           sqlite3HeaderSizePcache() +
465           sqlite3HeaderSizePcache1();
466       break;
467     }
468 
469     case SQLITE_CONFIG_PCACHE: {
470       /* no-op */
471       break;
472     }
473     case SQLITE_CONFIG_GETPCACHE: {
474       /* now an error */
475       rc = SQLITE_ERROR;
476       break;
477     }
478 
479     case SQLITE_CONFIG_PCACHE2: {
480       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
481       ** single argument which is a pointer to an sqlite3_pcache_methods2
482       ** object. This object specifies the interface to a custom page cache
483       ** implementation. */
484       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
485       break;
486     }
487     case SQLITE_CONFIG_GETPCACHE2: {
488       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
489       ** single argument which is a pointer to an sqlite3_pcache_methods2
490       ** object. SQLite copies of the current page cache implementation into
491       ** that object. */
492       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
493         sqlite3PCacheSetDefault();
494       }
495       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
496       break;
497     }
498 
499 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
500 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
501 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
502 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
503     case SQLITE_CONFIG_HEAP: {
504       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
505       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
506       ** number of bytes in the memory buffer, and the minimum allocation size.
507       */
508       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
509       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
510       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
511 
512       if( sqlite3GlobalConfig.mnReq<1 ){
513         sqlite3GlobalConfig.mnReq = 1;
514       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
515         /* cap min request size at 2^12 */
516         sqlite3GlobalConfig.mnReq = (1<<12);
517       }
518 
519       if( sqlite3GlobalConfig.pHeap==0 ){
520         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
521         ** is NULL, then SQLite reverts to using its default memory allocator
522         ** (the system malloc() implementation), undoing any prior invocation of
523         ** SQLITE_CONFIG_MALLOC.
524         **
525         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
526         ** revert to its default implementation when sqlite3_initialize() is run
527         */
528         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
529       }else{
530         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
531         ** alternative memory allocator is engaged to handle all of SQLites
532         ** memory allocation needs. */
533 #ifdef SQLITE_ENABLE_MEMSYS3
534         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
535 #endif
536 #ifdef SQLITE_ENABLE_MEMSYS5
537         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
538 #endif
539       }
540       break;
541     }
542 #endif
543 
544     case SQLITE_CONFIG_LOOKASIDE: {
545       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
546       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
547       break;
548     }
549 
550     /* Record a pointer to the logger function and its first argument.
551     ** The default is NULL.  Logging is disabled if the function pointer is
552     ** NULL.
553     */
554     case SQLITE_CONFIG_LOG: {
555       /* MSVC is picky about pulling func ptrs from va lists.
556       ** http://support.microsoft.com/kb/47961
557       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
558       */
559       typedef void(*LOGFUNC_t)(void*,int,const char*);
560       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
561       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
562       break;
563     }
564 
565     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
566     ** can be changed at start-time using the
567     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
568     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
569     */
570     case SQLITE_CONFIG_URI: {
571       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
572       ** argument of type int. If non-zero, then URI handling is globally
573       ** enabled. If the parameter is zero, then URI handling is globally
574       ** disabled. */
575       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
576       break;
577     }
578 
579     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
580       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
581       ** option takes a single integer argument which is interpreted as a
582       ** boolean in order to enable or disable the use of covering indices for
583       ** full table scans in the query optimizer. */
584       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
585       break;
586     }
587 
588 #ifdef SQLITE_ENABLE_SQLLOG
589     case SQLITE_CONFIG_SQLLOG: {
590       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
591       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
592       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
593       break;
594     }
595 #endif
596 
597     case SQLITE_CONFIG_MMAP_SIZE: {
598       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
599       ** integer (sqlite3_int64) values that are the default mmap size limit
600       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
601       ** mmap size limit. */
602       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
603       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
604       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
605       ** negative, then that argument is changed to its compile-time default.
606       **
607       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
608       ** silently truncated if necessary so that it does not exceed the
609       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
610       ** compile-time option.
611       */
612       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
613         mxMmap = SQLITE_MAX_MMAP_SIZE;
614       }
615       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
616       if( szMmap>mxMmap) szMmap = mxMmap;
617       sqlite3GlobalConfig.mxMmap = mxMmap;
618       sqlite3GlobalConfig.szMmap = szMmap;
619       break;
620     }
621 
622 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
623     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
624       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
625       ** unsigned integer value that specifies the maximum size of the created
626       ** heap. */
627       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
628       break;
629     }
630 #endif
631 
632     case SQLITE_CONFIG_PMASZ: {
633       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
634       break;
635     }
636 
637     default: {
638       rc = SQLITE_ERROR;
639       break;
640     }
641   }
642   va_end(ap);
643   return rc;
644 }
645 
646 /*
647 ** Set up the lookaside buffers for a database connection.
648 ** Return SQLITE_OK on success.
649 ** If lookaside is already active, return SQLITE_BUSY.
650 **
651 ** The sz parameter is the number of bytes in each lookaside slot.
652 ** The cnt parameter is the number of slots.  If pStart is NULL the
653 ** space for the lookaside memory is obtained from sqlite3_malloc().
654 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
655 ** the lookaside memory.
656 */
657 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
658 #ifndef SQLITE_OMIT_LOOKASIDE
659   void *pStart;
660   if( db->lookaside.nOut ){
661     return SQLITE_BUSY;
662   }
663   /* Free any existing lookaside buffer for this handle before
664   ** allocating a new one so we don't have to have space for
665   ** both at the same time.
666   */
667   if( db->lookaside.bMalloced ){
668     sqlite3_free(db->lookaside.pStart);
669   }
670   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
671   ** than a pointer to be useful.
672   */
673   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
674   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
675   if( cnt<0 ) cnt = 0;
676   if( sz==0 || cnt==0 ){
677     sz = 0;
678     pStart = 0;
679   }else if( pBuf==0 ){
680     sqlite3BeginBenignMalloc();
681     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
682     sqlite3EndBenignMalloc();
683     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
684   }else{
685     pStart = pBuf;
686   }
687   db->lookaside.pStart = pStart;
688   db->lookaside.pFree = 0;
689   db->lookaside.sz = (u16)sz;
690   if( pStart ){
691     int i;
692     LookasideSlot *p;
693     assert( sz > (int)sizeof(LookasideSlot*) );
694     p = (LookasideSlot*)pStart;
695     for(i=cnt-1; i>=0; i--){
696       p->pNext = db->lookaside.pFree;
697       db->lookaside.pFree = p;
698       p = (LookasideSlot*)&((u8*)p)[sz];
699     }
700     db->lookaside.pEnd = p;
701     db->lookaside.bDisable = 0;
702     db->lookaside.bMalloced = pBuf==0 ?1:0;
703   }else{
704     db->lookaside.pStart = db;
705     db->lookaside.pEnd = db;
706     db->lookaside.bDisable = 1;
707     db->lookaside.bMalloced = 0;
708   }
709 #endif /* SQLITE_OMIT_LOOKASIDE */
710   return SQLITE_OK;
711 }
712 
713 /*
714 ** Return the mutex associated with a database connection.
715 */
716 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
717 #ifdef SQLITE_ENABLE_API_ARMOR
718   if( !sqlite3SafetyCheckOk(db) ){
719     (void)SQLITE_MISUSE_BKPT;
720     return 0;
721   }
722 #endif
723   return db->mutex;
724 }
725 
726 /*
727 ** Free up as much memory as we can from the given database
728 ** connection.
729 */
730 int sqlite3_db_release_memory(sqlite3 *db){
731   int i;
732 
733 #ifdef SQLITE_ENABLE_API_ARMOR
734   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
735 #endif
736   sqlite3_mutex_enter(db->mutex);
737   sqlite3BtreeEnterAll(db);
738   for(i=0; i<db->nDb; i++){
739     Btree *pBt = db->aDb[i].pBt;
740     if( pBt ){
741       Pager *pPager = sqlite3BtreePager(pBt);
742       sqlite3PagerShrink(pPager);
743     }
744   }
745   sqlite3BtreeLeaveAll(db);
746   sqlite3_mutex_leave(db->mutex);
747   return SQLITE_OK;
748 }
749 
750 /*
751 ** Flush any dirty pages in the pager-cache for any attached database
752 ** to disk.
753 */
754 int sqlite3_db_cacheflush(sqlite3 *db){
755   int i;
756   int rc = SQLITE_OK;
757   int bSeenBusy = 0;
758 
759 #ifdef SQLITE_ENABLE_API_ARMOR
760   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
761 #endif
762   sqlite3_mutex_enter(db->mutex);
763   sqlite3BtreeEnterAll(db);
764   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
765     Btree *pBt = db->aDb[i].pBt;
766     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
767       Pager *pPager = sqlite3BtreePager(pBt);
768       rc = sqlite3PagerFlush(pPager);
769       if( rc==SQLITE_BUSY ){
770         bSeenBusy = 1;
771         rc = SQLITE_OK;
772       }
773     }
774   }
775   sqlite3BtreeLeaveAll(db);
776   sqlite3_mutex_leave(db->mutex);
777   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
778 }
779 
780 /*
781 ** Configuration settings for an individual database connection
782 */
783 int sqlite3_db_config(sqlite3 *db, int op, ...){
784   va_list ap;
785   int rc;
786   va_start(ap, op);
787   switch( op ){
788     case SQLITE_DBCONFIG_LOOKASIDE: {
789       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
790       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
791       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
792       rc = setupLookaside(db, pBuf, sz, cnt);
793       break;
794     }
795     default: {
796       static const struct {
797         int op;      /* The opcode */
798         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
799       } aFlagOp[] = {
800         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
801         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
802       };
803       unsigned int i;
804       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
805       for(i=0; i<ArraySize(aFlagOp); i++){
806         if( aFlagOp[i].op==op ){
807           int onoff = va_arg(ap, int);
808           int *pRes = va_arg(ap, int*);
809           int oldFlags = db->flags;
810           if( onoff>0 ){
811             db->flags |= aFlagOp[i].mask;
812           }else if( onoff==0 ){
813             db->flags &= ~aFlagOp[i].mask;
814           }
815           if( oldFlags!=db->flags ){
816             sqlite3ExpirePreparedStatements(db);
817           }
818           if( pRes ){
819             *pRes = (db->flags & aFlagOp[i].mask)!=0;
820           }
821           rc = SQLITE_OK;
822           break;
823         }
824       }
825       break;
826     }
827   }
828   va_end(ap);
829   return rc;
830 }
831 
832 
833 /*
834 ** Return true if the buffer z[0..n-1] contains all spaces.
835 */
836 static int allSpaces(const char *z, int n){
837   while( n>0 && z[n-1]==' ' ){ n--; }
838   return n==0;
839 }
840 
841 /*
842 ** This is the default collating function named "BINARY" which is always
843 ** available.
844 **
845 ** If the padFlag argument is not NULL then space padding at the end
846 ** of strings is ignored.  This implements the RTRIM collation.
847 */
848 static int binCollFunc(
849   void *padFlag,
850   int nKey1, const void *pKey1,
851   int nKey2, const void *pKey2
852 ){
853   int rc, n;
854   n = nKey1<nKey2 ? nKey1 : nKey2;
855   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
856   ** strings byte by byte using the memcmp() function from the standard C
857   ** library. */
858   rc = memcmp(pKey1, pKey2, n);
859   if( rc==0 ){
860     if( padFlag
861      && allSpaces(((char*)pKey1)+n, nKey1-n)
862      && allSpaces(((char*)pKey2)+n, nKey2-n)
863     ){
864       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
865       ** spaces at the end of either string do not change the result. In other
866       ** words, strings will compare equal to one another as long as they
867       ** differ only in the number of spaces at the end.
868       */
869     }else{
870       rc = nKey1 - nKey2;
871     }
872   }
873   return rc;
874 }
875 
876 /*
877 ** Another built-in collating sequence: NOCASE.
878 **
879 ** This collating sequence is intended to be used for "case independent
880 ** comparison". SQLite's knowledge of upper and lower case equivalents
881 ** extends only to the 26 characters used in the English language.
882 **
883 ** At the moment there is only a UTF-8 implementation.
884 */
885 static int nocaseCollatingFunc(
886   void *NotUsed,
887   int nKey1, const void *pKey1,
888   int nKey2, const void *pKey2
889 ){
890   int r = sqlite3StrNICmp(
891       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
892   UNUSED_PARAMETER(NotUsed);
893   if( 0==r ){
894     r = nKey1-nKey2;
895   }
896   return r;
897 }
898 
899 /*
900 ** Return the ROWID of the most recent insert
901 */
902 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
903 #ifdef SQLITE_ENABLE_API_ARMOR
904   if( !sqlite3SafetyCheckOk(db) ){
905     (void)SQLITE_MISUSE_BKPT;
906     return 0;
907   }
908 #endif
909   return db->lastRowid;
910 }
911 
912 /*
913 ** Return the number of changes in the most recent call to sqlite3_exec().
914 */
915 int sqlite3_changes(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->nChange;
923 }
924 
925 /*
926 ** Return the number of changes since the database handle was opened.
927 */
928 int sqlite3_total_changes(sqlite3 *db){
929 #ifdef SQLITE_ENABLE_API_ARMOR
930   if( !sqlite3SafetyCheckOk(db) ){
931     (void)SQLITE_MISUSE_BKPT;
932     return 0;
933   }
934 #endif
935   return db->nTotalChange;
936 }
937 
938 /*
939 ** Close all open savepoints. This function only manipulates fields of the
940 ** database handle object, it does not close any savepoints that may be open
941 ** at the b-tree/pager level.
942 */
943 void sqlite3CloseSavepoints(sqlite3 *db){
944   while( db->pSavepoint ){
945     Savepoint *pTmp = db->pSavepoint;
946     db->pSavepoint = pTmp->pNext;
947     sqlite3DbFree(db, pTmp);
948   }
949   db->nSavepoint = 0;
950   db->nStatement = 0;
951   db->isTransactionSavepoint = 0;
952 }
953 
954 /*
955 ** Invoke the destructor function associated with FuncDef p, if any. Except,
956 ** if this is not the last copy of the function, do not invoke it. Multiple
957 ** copies of a single function are created when create_function() is called
958 ** with SQLITE_ANY as the encoding.
959 */
960 static void functionDestroy(sqlite3 *db, FuncDef *p){
961   FuncDestructor *pDestructor = p->pDestructor;
962   if( pDestructor ){
963     pDestructor->nRef--;
964     if( pDestructor->nRef==0 ){
965       pDestructor->xDestroy(pDestructor->pUserData);
966       sqlite3DbFree(db, pDestructor);
967     }
968   }
969 }
970 
971 /*
972 ** Disconnect all sqlite3_vtab objects that belong to database connection
973 ** db. This is called when db is being closed.
974 */
975 static void disconnectAllVtab(sqlite3 *db){
976 #ifndef SQLITE_OMIT_VIRTUALTABLE
977   int i;
978   HashElem *p;
979   sqlite3BtreeEnterAll(db);
980   for(i=0; i<db->nDb; i++){
981     Schema *pSchema = db->aDb[i].pSchema;
982     if( db->aDb[i].pSchema ){
983       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
984         Table *pTab = (Table *)sqliteHashData(p);
985         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
986       }
987     }
988   }
989   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
990     Module *pMod = (Module *)sqliteHashData(p);
991     if( pMod->pEpoTab ){
992       sqlite3VtabDisconnect(db, pMod->pEpoTab);
993     }
994   }
995   sqlite3VtabUnlockList(db);
996   sqlite3BtreeLeaveAll(db);
997 #else
998   UNUSED_PARAMETER(db);
999 #endif
1000 }
1001 
1002 /*
1003 ** Return TRUE if database connection db has unfinalized prepared
1004 ** statements or unfinished sqlite3_backup objects.
1005 */
1006 static int connectionIsBusy(sqlite3 *db){
1007   int j;
1008   assert( sqlite3_mutex_held(db->mutex) );
1009   if( db->pVdbe ) return 1;
1010   for(j=0; j<db->nDb; j++){
1011     Btree *pBt = db->aDb[j].pBt;
1012     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1013   }
1014   return 0;
1015 }
1016 
1017 /*
1018 ** Close an existing SQLite database
1019 */
1020 static int sqlite3Close(sqlite3 *db, int forceZombie){
1021   if( !db ){
1022     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1023     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1024     return SQLITE_OK;
1025   }
1026   if( !sqlite3SafetyCheckSickOrOk(db) ){
1027     return SQLITE_MISUSE_BKPT;
1028   }
1029   sqlite3_mutex_enter(db->mutex);
1030 
1031   /* Force xDisconnect calls on all virtual tables */
1032   disconnectAllVtab(db);
1033 
1034   /* If a transaction is open, the disconnectAllVtab() call above
1035   ** will not have called the xDisconnect() method on any virtual
1036   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1037   ** call will do so. We need to do this before the check for active
1038   ** SQL statements below, as the v-table implementation may be storing
1039   ** some prepared statements internally.
1040   */
1041   sqlite3VtabRollback(db);
1042 
1043   /* Legacy behavior (sqlite3_close() behavior) is to return
1044   ** SQLITE_BUSY if the connection can not be closed immediately.
1045   */
1046   if( !forceZombie && connectionIsBusy(db) ){
1047     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1048        "statements or unfinished backups");
1049     sqlite3_mutex_leave(db->mutex);
1050     return SQLITE_BUSY;
1051   }
1052 
1053 #ifdef SQLITE_ENABLE_SQLLOG
1054   if( sqlite3GlobalConfig.xSqllog ){
1055     /* Closing the handle. Fourth parameter is passed the value 2. */
1056     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1057   }
1058 #endif
1059 
1060   /* Convert the connection into a zombie and then close it.
1061   */
1062   db->magic = SQLITE_MAGIC_ZOMBIE;
1063   sqlite3LeaveMutexAndCloseZombie(db);
1064   return SQLITE_OK;
1065 }
1066 
1067 /*
1068 ** Two variations on the public interface for closing a database
1069 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1070 ** leaves the connection option if there are unfinalized prepared
1071 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1072 ** version forces the connection to become a zombie if there are
1073 ** unclosed resources, and arranges for deallocation when the last
1074 ** prepare statement or sqlite3_backup closes.
1075 */
1076 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1077 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1078 
1079 
1080 /*
1081 ** Close the mutex on database connection db.
1082 **
1083 ** Furthermore, if database connection db is a zombie (meaning that there
1084 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1085 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1086 ** finished, then free all resources.
1087 */
1088 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1089   HashElem *i;                    /* Hash table iterator */
1090   int j;
1091 
1092   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1093   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1094   ** then just leave the mutex and return.
1095   */
1096   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1097     sqlite3_mutex_leave(db->mutex);
1098     return;
1099   }
1100 
1101   /* If we reach this point, it means that the database connection has
1102   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1103   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1104   ** go ahead and free all resources.
1105   */
1106 
1107   /* If a transaction is open, roll it back. This also ensures that if
1108   ** any database schemas have been modified by an uncommitted transaction
1109   ** they are reset. And that the required b-tree mutex is held to make
1110   ** the pager rollback and schema reset an atomic operation. */
1111   sqlite3RollbackAll(db, SQLITE_OK);
1112 
1113   /* Free any outstanding Savepoint structures. */
1114   sqlite3CloseSavepoints(db);
1115 
1116   /* Close all database connections */
1117   for(j=0; j<db->nDb; j++){
1118     struct Db *pDb = &db->aDb[j];
1119     if( pDb->pBt ){
1120       sqlite3BtreeClose(pDb->pBt);
1121       pDb->pBt = 0;
1122       if( j!=1 ){
1123         pDb->pSchema = 0;
1124       }
1125     }
1126   }
1127   /* Clear the TEMP schema separately and last */
1128   if( db->aDb[1].pSchema ){
1129     sqlite3SchemaClear(db->aDb[1].pSchema);
1130   }
1131   sqlite3VtabUnlockList(db);
1132 
1133   /* Free up the array of auxiliary databases */
1134   sqlite3CollapseDatabaseArray(db);
1135   assert( db->nDb<=2 );
1136   assert( db->aDb==db->aDbStatic );
1137 
1138   /* Tell the code in notify.c that the connection no longer holds any
1139   ** locks and does not require any further unlock-notify callbacks.
1140   */
1141   sqlite3ConnectionClosed(db);
1142 
1143   for(j=0; j<ArraySize(db->aFunc.a); j++){
1144     FuncDef *pNext, *pHash, *p;
1145     for(p=db->aFunc.a[j]; p; p=pHash){
1146       pHash = p->pHash;
1147       while( p ){
1148         functionDestroy(db, p);
1149         pNext = p->pNext;
1150         sqlite3DbFree(db, p);
1151         p = pNext;
1152       }
1153     }
1154   }
1155   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1156     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1157     /* Invoke any destructors registered for collation sequence user data. */
1158     for(j=0; j<3; j++){
1159       if( pColl[j].xDel ){
1160         pColl[j].xDel(pColl[j].pUser);
1161       }
1162     }
1163     sqlite3DbFree(db, pColl);
1164   }
1165   sqlite3HashClear(&db->aCollSeq);
1166 #ifndef SQLITE_OMIT_VIRTUALTABLE
1167   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1168     Module *pMod = (Module *)sqliteHashData(i);
1169     if( pMod->xDestroy ){
1170       pMod->xDestroy(pMod->pAux);
1171     }
1172     sqlite3VtabEponymousTableClear(db, pMod);
1173     sqlite3DbFree(db, pMod);
1174   }
1175   sqlite3HashClear(&db->aModule);
1176 #endif
1177 
1178   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1179   sqlite3ValueFree(db->pErr);
1180   sqlite3CloseExtensions(db);
1181 #if SQLITE_USER_AUTHENTICATION
1182   sqlite3_free(db->auth.zAuthUser);
1183   sqlite3_free(db->auth.zAuthPW);
1184 #endif
1185 
1186   db->magic = SQLITE_MAGIC_ERROR;
1187 
1188   /* The temp-database schema is allocated differently from the other schema
1189   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1190   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1191   ** the same sqliteMalloc() as the one that allocates the database
1192   ** structure?
1193   */
1194   sqlite3DbFree(db, db->aDb[1].pSchema);
1195   sqlite3_mutex_leave(db->mutex);
1196   db->magic = SQLITE_MAGIC_CLOSED;
1197   sqlite3_mutex_free(db->mutex);
1198   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1199   if( db->lookaside.bMalloced ){
1200     sqlite3_free(db->lookaside.pStart);
1201   }
1202   sqlite3_free(db);
1203 }
1204 
1205 /*
1206 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1207 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1208 ** breaker") and made to return tripCode if there are any further
1209 ** attempts to use that cursor.  Read cursors remain open and valid
1210 ** but are "saved" in case the table pages are moved around.
1211 */
1212 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1213   int i;
1214   int inTrans = 0;
1215   int schemaChange;
1216   assert( sqlite3_mutex_held(db->mutex) );
1217   sqlite3BeginBenignMalloc();
1218 
1219   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1220   ** This is important in case the transaction being rolled back has
1221   ** modified the database schema. If the b-tree mutexes are not taken
1222   ** here, then another shared-cache connection might sneak in between
1223   ** the database rollback and schema reset, which can cause false
1224   ** corruption reports in some cases.  */
1225   sqlite3BtreeEnterAll(db);
1226   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1227 
1228   for(i=0; i<db->nDb; i++){
1229     Btree *p = db->aDb[i].pBt;
1230     if( p ){
1231       if( sqlite3BtreeIsInTrans(p) ){
1232         inTrans = 1;
1233       }
1234       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1235     }
1236   }
1237   sqlite3VtabRollback(db);
1238   sqlite3EndBenignMalloc();
1239 
1240   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1241     sqlite3ExpirePreparedStatements(db);
1242     sqlite3ResetAllSchemasOfConnection(db);
1243   }
1244   sqlite3BtreeLeaveAll(db);
1245 
1246   /* Any deferred constraint violations have now been resolved. */
1247   db->nDeferredCons = 0;
1248   db->nDeferredImmCons = 0;
1249   db->flags &= ~SQLITE_DeferFKs;
1250 
1251   /* If one has been configured, invoke the rollback-hook callback */
1252   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1253     db->xRollbackCallback(db->pRollbackArg);
1254   }
1255 }
1256 
1257 /*
1258 ** Return a static string containing the name corresponding to the error code
1259 ** specified in the argument.
1260 */
1261 #if defined(SQLITE_NEED_ERR_NAME)
1262 const char *sqlite3ErrName(int rc){
1263   const char *zName = 0;
1264   int i, origRc = rc;
1265   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1266     switch( rc ){
1267       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1268       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1269       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1270       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1271       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1272       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1273       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1274       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1275       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1276       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1277       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1278       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1279       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1280       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1281       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1282       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1283       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1284       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1285       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1286       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1287       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1288       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1289       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1290       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1291       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1292       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1293       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1294       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1295       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1296       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1297       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1298       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1299                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1300       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1301       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1302       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1303       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1304       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1305       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1306       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1307       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1308       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1309       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1310       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1311       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1312       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1313       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1314       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1315       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1316       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1317       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1318       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1319       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1320       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1321       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1322       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1323       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1324       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1325       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1326       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1327       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1328       case SQLITE_CONSTRAINT_FOREIGNKEY:
1329                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1330       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1331       case SQLITE_CONSTRAINT_PRIMARYKEY:
1332                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1333       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1334       case SQLITE_CONSTRAINT_COMMITHOOK:
1335                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1336       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1337       case SQLITE_CONSTRAINT_FUNCTION:
1338                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1339       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1340       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1341       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1342       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1343       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1344       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1345       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1346       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1347       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1348       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1349       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1350       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1351                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1352       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1353       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1354       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1355     }
1356   }
1357   if( zName==0 ){
1358     static char zBuf[50];
1359     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1360     zName = zBuf;
1361   }
1362   return zName;
1363 }
1364 #endif
1365 
1366 /*
1367 ** Return a static string that describes the kind of error specified in the
1368 ** argument.
1369 */
1370 const char *sqlite3ErrStr(int rc){
1371   static const char* const aMsg[] = {
1372     /* SQLITE_OK          */ "not an error",
1373     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1374     /* SQLITE_INTERNAL    */ 0,
1375     /* SQLITE_PERM        */ "access permission denied",
1376     /* SQLITE_ABORT       */ "callback requested query abort",
1377     /* SQLITE_BUSY        */ "database is locked",
1378     /* SQLITE_LOCKED      */ "database table is locked",
1379     /* SQLITE_NOMEM       */ "out of memory",
1380     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1381     /* SQLITE_INTERRUPT   */ "interrupted",
1382     /* SQLITE_IOERR       */ "disk I/O error",
1383     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1384     /* SQLITE_NOTFOUND    */ "unknown operation",
1385     /* SQLITE_FULL        */ "database or disk is full",
1386     /* SQLITE_CANTOPEN    */ "unable to open database file",
1387     /* SQLITE_PROTOCOL    */ "locking protocol",
1388     /* SQLITE_EMPTY       */ "table contains no data",
1389     /* SQLITE_SCHEMA      */ "database schema has changed",
1390     /* SQLITE_TOOBIG      */ "string or blob too big",
1391     /* SQLITE_CONSTRAINT  */ "constraint failed",
1392     /* SQLITE_MISMATCH    */ "datatype mismatch",
1393     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1394     /* SQLITE_NOLFS       */ "large file support is disabled",
1395     /* SQLITE_AUTH        */ "authorization denied",
1396     /* SQLITE_FORMAT      */ "auxiliary database format error",
1397     /* SQLITE_RANGE       */ "bind or column index out of range",
1398     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1399   };
1400   const char *zErr = "unknown error";
1401   switch( rc ){
1402     case SQLITE_ABORT_ROLLBACK: {
1403       zErr = "abort due to ROLLBACK";
1404       break;
1405     }
1406     default: {
1407       rc &= 0xff;
1408       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1409         zErr = aMsg[rc];
1410       }
1411       break;
1412     }
1413   }
1414   return zErr;
1415 }
1416 
1417 /*
1418 ** This routine implements a busy callback that sleeps and tries
1419 ** again until a timeout value is reached.  The timeout value is
1420 ** an integer number of milliseconds passed in as the first
1421 ** argument.
1422 */
1423 static int sqliteDefaultBusyCallback(
1424  void *ptr,               /* Database connection */
1425  int count                /* Number of times table has been busy */
1426 ){
1427 #if SQLITE_OS_WIN || HAVE_USLEEP
1428   static const u8 delays[] =
1429      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1430   static const u8 totals[] =
1431      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1432 # define NDELAY ArraySize(delays)
1433   sqlite3 *db = (sqlite3 *)ptr;
1434   int timeout = db->busyTimeout;
1435   int delay, prior;
1436 
1437   assert( count>=0 );
1438   if( count < NDELAY ){
1439     delay = delays[count];
1440     prior = totals[count];
1441   }else{
1442     delay = delays[NDELAY-1];
1443     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1444   }
1445   if( prior + delay > timeout ){
1446     delay = timeout - prior;
1447     if( delay<=0 ) return 0;
1448   }
1449   sqlite3OsSleep(db->pVfs, delay*1000);
1450   return 1;
1451 #else
1452   sqlite3 *db = (sqlite3 *)ptr;
1453   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1454   if( (count+1)*1000 > timeout ){
1455     return 0;
1456   }
1457   sqlite3OsSleep(db->pVfs, 1000000);
1458   return 1;
1459 #endif
1460 }
1461 
1462 /*
1463 ** Invoke the given busy handler.
1464 **
1465 ** This routine is called when an operation failed with a lock.
1466 ** If this routine returns non-zero, the lock is retried.  If it
1467 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1468 */
1469 int sqlite3InvokeBusyHandler(BusyHandler *p){
1470   int rc;
1471   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1472   rc = p->xFunc(p->pArg, p->nBusy);
1473   if( rc==0 ){
1474     p->nBusy = -1;
1475   }else{
1476     p->nBusy++;
1477   }
1478   return rc;
1479 }
1480 
1481 /*
1482 ** This routine sets the busy callback for an Sqlite database to the
1483 ** given callback function with the given argument.
1484 */
1485 int sqlite3_busy_handler(
1486   sqlite3 *db,
1487   int (*xBusy)(void*,int),
1488   void *pArg
1489 ){
1490 #ifdef SQLITE_ENABLE_API_ARMOR
1491   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1492 #endif
1493   sqlite3_mutex_enter(db->mutex);
1494   db->busyHandler.xFunc = xBusy;
1495   db->busyHandler.pArg = pArg;
1496   db->busyHandler.nBusy = 0;
1497   db->busyTimeout = 0;
1498   sqlite3_mutex_leave(db->mutex);
1499   return SQLITE_OK;
1500 }
1501 
1502 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1503 /*
1504 ** This routine sets the progress callback for an Sqlite database to the
1505 ** given callback function with the given argument. The progress callback will
1506 ** be invoked every nOps opcodes.
1507 */
1508 void sqlite3_progress_handler(
1509   sqlite3 *db,
1510   int nOps,
1511   int (*xProgress)(void*),
1512   void *pArg
1513 ){
1514 #ifdef SQLITE_ENABLE_API_ARMOR
1515   if( !sqlite3SafetyCheckOk(db) ){
1516     (void)SQLITE_MISUSE_BKPT;
1517     return;
1518   }
1519 #endif
1520   sqlite3_mutex_enter(db->mutex);
1521   if( nOps>0 ){
1522     db->xProgress = xProgress;
1523     db->nProgressOps = (unsigned)nOps;
1524     db->pProgressArg = pArg;
1525   }else{
1526     db->xProgress = 0;
1527     db->nProgressOps = 0;
1528     db->pProgressArg = 0;
1529   }
1530   sqlite3_mutex_leave(db->mutex);
1531 }
1532 #endif
1533 
1534 
1535 /*
1536 ** This routine installs a default busy handler that waits for the
1537 ** specified number of milliseconds before returning 0.
1538 */
1539 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1540 #ifdef SQLITE_ENABLE_API_ARMOR
1541   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1542 #endif
1543   if( ms>0 ){
1544     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1545     db->busyTimeout = ms;
1546   }else{
1547     sqlite3_busy_handler(db, 0, 0);
1548   }
1549   return SQLITE_OK;
1550 }
1551 
1552 /*
1553 ** Cause any pending operation to stop at its earliest opportunity.
1554 */
1555 void sqlite3_interrupt(sqlite3 *db){
1556 #ifdef SQLITE_ENABLE_API_ARMOR
1557   if( !sqlite3SafetyCheckOk(db) ){
1558     (void)SQLITE_MISUSE_BKPT;
1559     return;
1560   }
1561 #endif
1562   db->u1.isInterrupted = 1;
1563 }
1564 
1565 
1566 /*
1567 ** This function is exactly the same as sqlite3_create_function(), except
1568 ** that it is designed to be called by internal code. The difference is
1569 ** that if a malloc() fails in sqlite3_create_function(), an error code
1570 ** is returned and the mallocFailed flag cleared.
1571 */
1572 int sqlite3CreateFunc(
1573   sqlite3 *db,
1574   const char *zFunctionName,
1575   int nArg,
1576   int enc,
1577   void *pUserData,
1578   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1579   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1580   void (*xFinal)(sqlite3_context*),
1581   FuncDestructor *pDestructor
1582 ){
1583   FuncDef *p;
1584   int nName;
1585   int extraFlags;
1586 
1587   assert( sqlite3_mutex_held(db->mutex) );
1588   if( zFunctionName==0 ||
1589       (xSFunc && (xFinal || xStep)) ||
1590       (!xSFunc && (xFinal && !xStep)) ||
1591       (!xSFunc && (!xFinal && xStep)) ||
1592       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1593       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1594     return SQLITE_MISUSE_BKPT;
1595   }
1596 
1597   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1598   extraFlags = enc &  SQLITE_DETERMINISTIC;
1599   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1600 
1601 #ifndef SQLITE_OMIT_UTF16
1602   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1603   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1604   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1605   **
1606   ** If SQLITE_ANY is specified, add three versions of the function
1607   ** to the hash table.
1608   */
1609   if( enc==SQLITE_UTF16 ){
1610     enc = SQLITE_UTF16NATIVE;
1611   }else if( enc==SQLITE_ANY ){
1612     int rc;
1613     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1614          pUserData, xSFunc, xStep, xFinal, pDestructor);
1615     if( rc==SQLITE_OK ){
1616       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1617           pUserData, xSFunc, xStep, xFinal, pDestructor);
1618     }
1619     if( rc!=SQLITE_OK ){
1620       return rc;
1621     }
1622     enc = SQLITE_UTF16BE;
1623   }
1624 #else
1625   enc = SQLITE_UTF8;
1626 #endif
1627 
1628   /* Check if an existing function is being overridden or deleted. If so,
1629   ** and there are active VMs, then return SQLITE_BUSY. If a function
1630   ** is being overridden/deleted but there are no active VMs, allow the
1631   ** operation to continue but invalidate all precompiled statements.
1632   */
1633   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 0);
1634   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1635     if( db->nVdbeActive ){
1636       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1637         "unable to delete/modify user-function due to active statements");
1638       assert( !db->mallocFailed );
1639       return SQLITE_BUSY;
1640     }else{
1641       sqlite3ExpirePreparedStatements(db);
1642     }
1643   }
1644 
1645   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 1);
1646   assert(p || db->mallocFailed);
1647   if( !p ){
1648     return SQLITE_NOMEM;
1649   }
1650 
1651   /* If an older version of the function with a configured destructor is
1652   ** being replaced invoke the destructor function here. */
1653   functionDestroy(db, p);
1654 
1655   if( pDestructor ){
1656     pDestructor->nRef++;
1657   }
1658   p->pDestructor = pDestructor;
1659   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1660   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1661   p->xSFunc = xSFunc ? xSFunc : xStep;
1662   p->xFinalize = xFinal;
1663   p->pUserData = pUserData;
1664   p->nArg = (u16)nArg;
1665   return SQLITE_OK;
1666 }
1667 
1668 /*
1669 ** Create new user functions.
1670 */
1671 int sqlite3_create_function(
1672   sqlite3 *db,
1673   const char *zFunc,
1674   int nArg,
1675   int enc,
1676   void *p,
1677   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1678   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1679   void (*xFinal)(sqlite3_context*)
1680 ){
1681   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1682                                     xFinal, 0);
1683 }
1684 
1685 int sqlite3_create_function_v2(
1686   sqlite3 *db,
1687   const char *zFunc,
1688   int nArg,
1689   int enc,
1690   void *p,
1691   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1692   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1693   void (*xFinal)(sqlite3_context*),
1694   void (*xDestroy)(void *)
1695 ){
1696   int rc = SQLITE_ERROR;
1697   FuncDestructor *pArg = 0;
1698 
1699 #ifdef SQLITE_ENABLE_API_ARMOR
1700   if( !sqlite3SafetyCheckOk(db) ){
1701     return SQLITE_MISUSE_BKPT;
1702   }
1703 #endif
1704   sqlite3_mutex_enter(db->mutex);
1705   if( xDestroy ){
1706     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1707     if( !pArg ){
1708       xDestroy(p);
1709       goto out;
1710     }
1711     pArg->xDestroy = xDestroy;
1712     pArg->pUserData = p;
1713   }
1714   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1715   if( pArg && pArg->nRef==0 ){
1716     assert( rc!=SQLITE_OK );
1717     xDestroy(p);
1718     sqlite3DbFree(db, pArg);
1719   }
1720 
1721  out:
1722   rc = sqlite3ApiExit(db, rc);
1723   sqlite3_mutex_leave(db->mutex);
1724   return rc;
1725 }
1726 
1727 #ifndef SQLITE_OMIT_UTF16
1728 int sqlite3_create_function16(
1729   sqlite3 *db,
1730   const void *zFunctionName,
1731   int nArg,
1732   int eTextRep,
1733   void *p,
1734   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1735   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1736   void (*xFinal)(sqlite3_context*)
1737 ){
1738   int rc;
1739   char *zFunc8;
1740 
1741 #ifdef SQLITE_ENABLE_API_ARMOR
1742   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1743 #endif
1744   sqlite3_mutex_enter(db->mutex);
1745   assert( !db->mallocFailed );
1746   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1747   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1748   sqlite3DbFree(db, zFunc8);
1749   rc = sqlite3ApiExit(db, rc);
1750   sqlite3_mutex_leave(db->mutex);
1751   return rc;
1752 }
1753 #endif
1754 
1755 
1756 /*
1757 ** Declare that a function has been overloaded by a virtual table.
1758 **
1759 ** If the function already exists as a regular global function, then
1760 ** this routine is a no-op.  If the function does not exist, then create
1761 ** a new one that always throws a run-time error.
1762 **
1763 ** When virtual tables intend to provide an overloaded function, they
1764 ** should call this routine to make sure the global function exists.
1765 ** A global function must exist in order for name resolution to work
1766 ** properly.
1767 */
1768 int sqlite3_overload_function(
1769   sqlite3 *db,
1770   const char *zName,
1771   int nArg
1772 ){
1773   int nName = sqlite3Strlen30(zName);
1774   int rc = SQLITE_OK;
1775 
1776 #ifdef SQLITE_ENABLE_API_ARMOR
1777   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1778     return SQLITE_MISUSE_BKPT;
1779   }
1780 #endif
1781   sqlite3_mutex_enter(db->mutex);
1782   if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
1783     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1784                            0, sqlite3InvalidFunction, 0, 0, 0);
1785   }
1786   rc = sqlite3ApiExit(db, rc);
1787   sqlite3_mutex_leave(db->mutex);
1788   return rc;
1789 }
1790 
1791 #ifndef SQLITE_OMIT_TRACE
1792 /*
1793 ** Register a trace function.  The pArg from the previously registered trace
1794 ** is returned.
1795 **
1796 ** A NULL trace function means that no tracing is executes.  A non-NULL
1797 ** trace is a pointer to a function that is invoked at the start of each
1798 ** SQL statement.
1799 */
1800 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1801   void *pOld;
1802 
1803 #ifdef SQLITE_ENABLE_API_ARMOR
1804   if( !sqlite3SafetyCheckOk(db) ){
1805     (void)SQLITE_MISUSE_BKPT;
1806     return 0;
1807   }
1808 #endif
1809   sqlite3_mutex_enter(db->mutex);
1810   pOld = db->pTraceArg;
1811   db->xTrace = xTrace;
1812   db->pTraceArg = pArg;
1813   sqlite3_mutex_leave(db->mutex);
1814   return pOld;
1815 }
1816 /*
1817 ** Register a profile function.  The pArg from the previously registered
1818 ** profile function is returned.
1819 **
1820 ** A NULL profile function means that no profiling is executes.  A non-NULL
1821 ** profile is a pointer to a function that is invoked at the conclusion of
1822 ** each SQL statement that is run.
1823 */
1824 void *sqlite3_profile(
1825   sqlite3 *db,
1826   void (*xProfile)(void*,const char*,sqlite_uint64),
1827   void *pArg
1828 ){
1829   void *pOld;
1830 
1831 #ifdef SQLITE_ENABLE_API_ARMOR
1832   if( !sqlite3SafetyCheckOk(db) ){
1833     (void)SQLITE_MISUSE_BKPT;
1834     return 0;
1835   }
1836 #endif
1837   sqlite3_mutex_enter(db->mutex);
1838   pOld = db->pProfileArg;
1839   db->xProfile = xProfile;
1840   db->pProfileArg = pArg;
1841   sqlite3_mutex_leave(db->mutex);
1842   return pOld;
1843 }
1844 #endif /* SQLITE_OMIT_TRACE */
1845 
1846 /*
1847 ** Register a function to be invoked when a transaction commits.
1848 ** If the invoked function returns non-zero, then the commit becomes a
1849 ** rollback.
1850 */
1851 void *sqlite3_commit_hook(
1852   sqlite3 *db,              /* Attach the hook to this database */
1853   int (*xCallback)(void*),  /* Function to invoke on each commit */
1854   void *pArg                /* Argument to the function */
1855 ){
1856   void *pOld;
1857 
1858 #ifdef SQLITE_ENABLE_API_ARMOR
1859   if( !sqlite3SafetyCheckOk(db) ){
1860     (void)SQLITE_MISUSE_BKPT;
1861     return 0;
1862   }
1863 #endif
1864   sqlite3_mutex_enter(db->mutex);
1865   pOld = db->pCommitArg;
1866   db->xCommitCallback = xCallback;
1867   db->pCommitArg = pArg;
1868   sqlite3_mutex_leave(db->mutex);
1869   return pOld;
1870 }
1871 
1872 /*
1873 ** Register a callback to be invoked each time a row is updated,
1874 ** inserted or deleted using this database connection.
1875 */
1876 void *sqlite3_update_hook(
1877   sqlite3 *db,              /* Attach the hook to this database */
1878   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1879   void *pArg                /* Argument to the function */
1880 ){
1881   void *pRet;
1882 
1883 #ifdef SQLITE_ENABLE_API_ARMOR
1884   if( !sqlite3SafetyCheckOk(db) ){
1885     (void)SQLITE_MISUSE_BKPT;
1886     return 0;
1887   }
1888 #endif
1889   sqlite3_mutex_enter(db->mutex);
1890   pRet = db->pUpdateArg;
1891   db->xUpdateCallback = xCallback;
1892   db->pUpdateArg = pArg;
1893   sqlite3_mutex_leave(db->mutex);
1894   return pRet;
1895 }
1896 
1897 /*
1898 ** Register a callback to be invoked each time a transaction is rolled
1899 ** back by this database connection.
1900 */
1901 void *sqlite3_rollback_hook(
1902   sqlite3 *db,              /* Attach the hook to this database */
1903   void (*xCallback)(void*), /* Callback function */
1904   void *pArg                /* Argument to the function */
1905 ){
1906   void *pRet;
1907 
1908 #ifdef SQLITE_ENABLE_API_ARMOR
1909   if( !sqlite3SafetyCheckOk(db) ){
1910     (void)SQLITE_MISUSE_BKPT;
1911     return 0;
1912   }
1913 #endif
1914   sqlite3_mutex_enter(db->mutex);
1915   pRet = db->pRollbackArg;
1916   db->xRollbackCallback = xCallback;
1917   db->pRollbackArg = pArg;
1918   sqlite3_mutex_leave(db->mutex);
1919   return pRet;
1920 }
1921 
1922 #ifndef SQLITE_OMIT_WAL
1923 /*
1924 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1925 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1926 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1927 ** wal_autocheckpoint()).
1928 */
1929 int sqlite3WalDefaultHook(
1930   void *pClientData,     /* Argument */
1931   sqlite3 *db,           /* Connection */
1932   const char *zDb,       /* Database */
1933   int nFrame             /* Size of WAL */
1934 ){
1935   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1936     sqlite3BeginBenignMalloc();
1937     sqlite3_wal_checkpoint(db, zDb);
1938     sqlite3EndBenignMalloc();
1939   }
1940   return SQLITE_OK;
1941 }
1942 #endif /* SQLITE_OMIT_WAL */
1943 
1944 /*
1945 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1946 ** a database after committing a transaction if there are nFrame or
1947 ** more frames in the log file. Passing zero or a negative value as the
1948 ** nFrame parameter disables automatic checkpoints entirely.
1949 **
1950 ** The callback registered by this function replaces any existing callback
1951 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1952 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1953 ** configured by this function.
1954 */
1955 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1956 #ifdef SQLITE_OMIT_WAL
1957   UNUSED_PARAMETER(db);
1958   UNUSED_PARAMETER(nFrame);
1959 #else
1960 #ifdef SQLITE_ENABLE_API_ARMOR
1961   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1962 #endif
1963   if( nFrame>0 ){
1964     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1965   }else{
1966     sqlite3_wal_hook(db, 0, 0);
1967   }
1968 #endif
1969   return SQLITE_OK;
1970 }
1971 
1972 /*
1973 ** Register a callback to be invoked each time a transaction is written
1974 ** into the write-ahead-log by this database connection.
1975 */
1976 void *sqlite3_wal_hook(
1977   sqlite3 *db,                    /* Attach the hook to this db handle */
1978   int(*xCallback)(void *, sqlite3*, const char*, int),
1979   void *pArg                      /* First argument passed to xCallback() */
1980 ){
1981 #ifndef SQLITE_OMIT_WAL
1982   void *pRet;
1983 #ifdef SQLITE_ENABLE_API_ARMOR
1984   if( !sqlite3SafetyCheckOk(db) ){
1985     (void)SQLITE_MISUSE_BKPT;
1986     return 0;
1987   }
1988 #endif
1989   sqlite3_mutex_enter(db->mutex);
1990   pRet = db->pWalArg;
1991   db->xWalCallback = xCallback;
1992   db->pWalArg = pArg;
1993   sqlite3_mutex_leave(db->mutex);
1994   return pRet;
1995 #else
1996   return 0;
1997 #endif
1998 }
1999 
2000 /*
2001 ** Checkpoint database zDb.
2002 */
2003 int sqlite3_wal_checkpoint_v2(
2004   sqlite3 *db,                    /* Database handle */
2005   const char *zDb,                /* Name of attached database (or NULL) */
2006   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2007   int *pnLog,                     /* OUT: Size of WAL log in frames */
2008   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2009 ){
2010 #ifdef SQLITE_OMIT_WAL
2011   return SQLITE_OK;
2012 #else
2013   int rc;                         /* Return code */
2014   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2015 
2016 #ifdef SQLITE_ENABLE_API_ARMOR
2017   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2018 #endif
2019 
2020   /* Initialize the output variables to -1 in case an error occurs. */
2021   if( pnLog ) *pnLog = -1;
2022   if( pnCkpt ) *pnCkpt = -1;
2023 
2024   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2025   assert( SQLITE_CHECKPOINT_FULL==1 );
2026   assert( SQLITE_CHECKPOINT_RESTART==2 );
2027   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2028   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2029     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2030     ** mode: */
2031     return SQLITE_MISUSE;
2032   }
2033 
2034   sqlite3_mutex_enter(db->mutex);
2035   if( zDb && zDb[0] ){
2036     iDb = sqlite3FindDbName(db, zDb);
2037   }
2038   if( iDb<0 ){
2039     rc = SQLITE_ERROR;
2040     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2041   }else{
2042     db->busyHandler.nBusy = 0;
2043     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2044     sqlite3Error(db, rc);
2045   }
2046   rc = sqlite3ApiExit(db, rc);
2047   sqlite3_mutex_leave(db->mutex);
2048   return rc;
2049 #endif
2050 }
2051 
2052 
2053 /*
2054 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2055 ** to contains a zero-length string, all attached databases are
2056 ** checkpointed.
2057 */
2058 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2059   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2060   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2061   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2062 }
2063 
2064 #ifndef SQLITE_OMIT_WAL
2065 /*
2066 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2067 ** not currently open in WAL mode.
2068 **
2069 ** If a transaction is open on the database being checkpointed, this
2070 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2071 ** an error occurs while running the checkpoint, an SQLite error code is
2072 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2073 **
2074 ** The mutex on database handle db should be held by the caller. The mutex
2075 ** associated with the specific b-tree being checkpointed is taken by
2076 ** this function while the checkpoint is running.
2077 **
2078 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2079 ** checkpointed. If an error is encountered it is returned immediately -
2080 ** no attempt is made to checkpoint any remaining databases.
2081 **
2082 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2083 */
2084 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2085   int rc = SQLITE_OK;             /* Return code */
2086   int i;                          /* Used to iterate through attached dbs */
2087   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2088 
2089   assert( sqlite3_mutex_held(db->mutex) );
2090   assert( !pnLog || *pnLog==-1 );
2091   assert( !pnCkpt || *pnCkpt==-1 );
2092 
2093   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2094     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2095       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2096       pnLog = 0;
2097       pnCkpt = 0;
2098       if( rc==SQLITE_BUSY ){
2099         bBusy = 1;
2100         rc = SQLITE_OK;
2101       }
2102     }
2103   }
2104 
2105   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2106 }
2107 #endif /* SQLITE_OMIT_WAL */
2108 
2109 /*
2110 ** This function returns true if main-memory should be used instead of
2111 ** a temporary file for transient pager files and statement journals.
2112 ** The value returned depends on the value of db->temp_store (runtime
2113 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2114 ** following table describes the relationship between these two values
2115 ** and this functions return value.
2116 **
2117 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2118 **   -----------------     --------------     ------------------------------
2119 **   0                     any                file      (return 0)
2120 **   1                     1                  file      (return 0)
2121 **   1                     2                  memory    (return 1)
2122 **   1                     0                  file      (return 0)
2123 **   2                     1                  file      (return 0)
2124 **   2                     2                  memory    (return 1)
2125 **   2                     0                  memory    (return 1)
2126 **   3                     any                memory    (return 1)
2127 */
2128 int sqlite3TempInMemory(const sqlite3 *db){
2129 #if SQLITE_TEMP_STORE==1
2130   return ( db->temp_store==2 );
2131 #endif
2132 #if SQLITE_TEMP_STORE==2
2133   return ( db->temp_store!=1 );
2134 #endif
2135 #if SQLITE_TEMP_STORE==3
2136   UNUSED_PARAMETER(db);
2137   return 1;
2138 #endif
2139 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2140   UNUSED_PARAMETER(db);
2141   return 0;
2142 #endif
2143 }
2144 
2145 /*
2146 ** Return UTF-8 encoded English language explanation of the most recent
2147 ** error.
2148 */
2149 const char *sqlite3_errmsg(sqlite3 *db){
2150   const char *z;
2151   if( !db ){
2152     return sqlite3ErrStr(SQLITE_NOMEM);
2153   }
2154   if( !sqlite3SafetyCheckSickOrOk(db) ){
2155     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2156   }
2157   sqlite3_mutex_enter(db->mutex);
2158   if( db->mallocFailed ){
2159     z = sqlite3ErrStr(SQLITE_NOMEM);
2160   }else{
2161     testcase( db->pErr==0 );
2162     z = (char*)sqlite3_value_text(db->pErr);
2163     assert( !db->mallocFailed );
2164     if( z==0 ){
2165       z = sqlite3ErrStr(db->errCode);
2166     }
2167   }
2168   sqlite3_mutex_leave(db->mutex);
2169   return z;
2170 }
2171 
2172 #ifndef SQLITE_OMIT_UTF16
2173 /*
2174 ** Return UTF-16 encoded English language explanation of the most recent
2175 ** error.
2176 */
2177 const void *sqlite3_errmsg16(sqlite3 *db){
2178   static const u16 outOfMem[] = {
2179     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2180   };
2181   static const u16 misuse[] = {
2182     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2183     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2184     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2185     'o', 'u', 't', ' ',
2186     'o', 'f', ' ',
2187     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2188   };
2189 
2190   const void *z;
2191   if( !db ){
2192     return (void *)outOfMem;
2193   }
2194   if( !sqlite3SafetyCheckSickOrOk(db) ){
2195     return (void *)misuse;
2196   }
2197   sqlite3_mutex_enter(db->mutex);
2198   if( db->mallocFailed ){
2199     z = (void *)outOfMem;
2200   }else{
2201     z = sqlite3_value_text16(db->pErr);
2202     if( z==0 ){
2203       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2204       z = sqlite3_value_text16(db->pErr);
2205     }
2206     /* A malloc() may have failed within the call to sqlite3_value_text16()
2207     ** above. If this is the case, then the db->mallocFailed flag needs to
2208     ** be cleared before returning. Do this directly, instead of via
2209     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2210     */
2211     sqlite3OomClear(db);
2212   }
2213   sqlite3_mutex_leave(db->mutex);
2214   return z;
2215 }
2216 #endif /* SQLITE_OMIT_UTF16 */
2217 
2218 /*
2219 ** Return the most recent error code generated by an SQLite routine. If NULL is
2220 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2221 */
2222 int sqlite3_errcode(sqlite3 *db){
2223   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2224     return SQLITE_MISUSE_BKPT;
2225   }
2226   if( !db || db->mallocFailed ){
2227     return SQLITE_NOMEM;
2228   }
2229   return db->errCode & db->errMask;
2230 }
2231 int sqlite3_extended_errcode(sqlite3 *db){
2232   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2233     return SQLITE_MISUSE_BKPT;
2234   }
2235   if( !db || db->mallocFailed ){
2236     return SQLITE_NOMEM;
2237   }
2238   return db->errCode;
2239 }
2240 
2241 /*
2242 ** Return a string that describes the kind of error specified in the
2243 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2244 ** function.
2245 */
2246 const char *sqlite3_errstr(int rc){
2247   return sqlite3ErrStr(rc);
2248 }
2249 
2250 /*
2251 ** Create a new collating function for database "db".  The name is zName
2252 ** and the encoding is enc.
2253 */
2254 static int createCollation(
2255   sqlite3* db,
2256   const char *zName,
2257   u8 enc,
2258   void* pCtx,
2259   int(*xCompare)(void*,int,const void*,int,const void*),
2260   void(*xDel)(void*)
2261 ){
2262   CollSeq *pColl;
2263   int enc2;
2264 
2265   assert( sqlite3_mutex_held(db->mutex) );
2266 
2267   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2268   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2269   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2270   */
2271   enc2 = enc;
2272   testcase( enc2==SQLITE_UTF16 );
2273   testcase( enc2==SQLITE_UTF16_ALIGNED );
2274   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2275     enc2 = SQLITE_UTF16NATIVE;
2276   }
2277   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2278     return SQLITE_MISUSE_BKPT;
2279   }
2280 
2281   /* Check if this call is removing or replacing an existing collation
2282   ** sequence. If so, and there are active VMs, return busy. If there
2283   ** are no active VMs, invalidate any pre-compiled statements.
2284   */
2285   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2286   if( pColl && pColl->xCmp ){
2287     if( db->nVdbeActive ){
2288       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2289         "unable to delete/modify collation sequence due to active statements");
2290       return SQLITE_BUSY;
2291     }
2292     sqlite3ExpirePreparedStatements(db);
2293 
2294     /* If collation sequence pColl was created directly by a call to
2295     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2296     ** then any copies made by synthCollSeq() need to be invalidated.
2297     ** Also, collation destructor - CollSeq.xDel() - function may need
2298     ** to be called.
2299     */
2300     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2301       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2302       int j;
2303       for(j=0; j<3; j++){
2304         CollSeq *p = &aColl[j];
2305         if( p->enc==pColl->enc ){
2306           if( p->xDel ){
2307             p->xDel(p->pUser);
2308           }
2309           p->xCmp = 0;
2310         }
2311       }
2312     }
2313   }
2314 
2315   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2316   if( pColl==0 ) return SQLITE_NOMEM;
2317   pColl->xCmp = xCompare;
2318   pColl->pUser = pCtx;
2319   pColl->xDel = xDel;
2320   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2321   sqlite3Error(db, SQLITE_OK);
2322   return SQLITE_OK;
2323 }
2324 
2325 
2326 /*
2327 ** This array defines hard upper bounds on limit values.  The
2328 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2329 ** #defines in sqlite3.h.
2330 */
2331 static const int aHardLimit[] = {
2332   SQLITE_MAX_LENGTH,
2333   SQLITE_MAX_SQL_LENGTH,
2334   SQLITE_MAX_COLUMN,
2335   SQLITE_MAX_EXPR_DEPTH,
2336   SQLITE_MAX_COMPOUND_SELECT,
2337   SQLITE_MAX_VDBE_OP,
2338   SQLITE_MAX_FUNCTION_ARG,
2339   SQLITE_MAX_ATTACHED,
2340   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2341   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2342   SQLITE_MAX_TRIGGER_DEPTH,
2343   SQLITE_MAX_WORKER_THREADS,
2344 };
2345 
2346 /*
2347 ** Make sure the hard limits are set to reasonable values
2348 */
2349 #if SQLITE_MAX_LENGTH<100
2350 # error SQLITE_MAX_LENGTH must be at least 100
2351 #endif
2352 #if SQLITE_MAX_SQL_LENGTH<100
2353 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2354 #endif
2355 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2356 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2357 #endif
2358 #if SQLITE_MAX_COMPOUND_SELECT<2
2359 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2360 #endif
2361 #if SQLITE_MAX_VDBE_OP<40
2362 # error SQLITE_MAX_VDBE_OP must be at least 40
2363 #endif
2364 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
2365 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
2366 #endif
2367 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2368 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2369 #endif
2370 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2371 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2372 #endif
2373 #if SQLITE_MAX_COLUMN>32767
2374 # error SQLITE_MAX_COLUMN must not exceed 32767
2375 #endif
2376 #if SQLITE_MAX_TRIGGER_DEPTH<1
2377 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2378 #endif
2379 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2380 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2381 #endif
2382 
2383 
2384 /*
2385 ** Change the value of a limit.  Report the old value.
2386 ** If an invalid limit index is supplied, report -1.
2387 ** Make no changes but still report the old value if the
2388 ** new limit is negative.
2389 **
2390 ** A new lower limit does not shrink existing constructs.
2391 ** It merely prevents new constructs that exceed the limit
2392 ** from forming.
2393 */
2394 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2395   int oldLimit;
2396 
2397 #ifdef SQLITE_ENABLE_API_ARMOR
2398   if( !sqlite3SafetyCheckOk(db) ){
2399     (void)SQLITE_MISUSE_BKPT;
2400     return -1;
2401   }
2402 #endif
2403 
2404   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2405   ** there is a hard upper bound set at compile-time by a C preprocessor
2406   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2407   ** "_MAX_".)
2408   */
2409   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2410   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2411   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2412   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2413   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2414   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2415   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2416   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2417   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2418                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2419   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2420   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2421   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2422   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2423 
2424 
2425   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2426     return -1;
2427   }
2428   oldLimit = db->aLimit[limitId];
2429   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2430     if( newLimit>aHardLimit[limitId] ){
2431       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2432     }
2433     db->aLimit[limitId] = newLimit;
2434   }
2435   return oldLimit;                     /* IMP: R-53341-35419 */
2436 }
2437 
2438 /*
2439 ** This function is used to parse both URIs and non-URI filenames passed by the
2440 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2441 ** URIs specified as part of ATTACH statements.
2442 **
2443 ** The first argument to this function is the name of the VFS to use (or
2444 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2445 ** query parameter. The second argument contains the URI (or non-URI filename)
2446 ** itself. When this function is called the *pFlags variable should contain
2447 ** the default flags to open the database handle with. The value stored in
2448 ** *pFlags may be updated before returning if the URI filename contains
2449 ** "cache=xxx" or "mode=xxx" query parameters.
2450 **
2451 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2452 ** the VFS that should be used to open the database file. *pzFile is set to
2453 ** point to a buffer containing the name of the file to open. It is the
2454 ** responsibility of the caller to eventually call sqlite3_free() to release
2455 ** this buffer.
2456 **
2457 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2458 ** may be set to point to a buffer containing an English language error
2459 ** message. It is the responsibility of the caller to eventually release
2460 ** this buffer by calling sqlite3_free().
2461 */
2462 int sqlite3ParseUri(
2463   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2464   const char *zUri,               /* Nul-terminated URI to parse */
2465   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2466   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2467   char **pzFile,                  /* OUT: Filename component of URI */
2468   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2469 ){
2470   int rc = SQLITE_OK;
2471   unsigned int flags = *pFlags;
2472   const char *zVfs = zDefaultVfs;
2473   char *zFile;
2474   char c;
2475   int nUri = sqlite3Strlen30(zUri);
2476 
2477   assert( *pzErrMsg==0 );
2478 
2479   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2480             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2481    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2482   ){
2483     char *zOpt;
2484     int eState;                   /* Parser state when parsing URI */
2485     int iIn;                      /* Input character index */
2486     int iOut = 0;                 /* Output character index */
2487     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2488 
2489     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2490     ** method that there may be extra parameters following the file-name.  */
2491     flags |= SQLITE_OPEN_URI;
2492 
2493     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2494     zFile = sqlite3_malloc64(nByte);
2495     if( !zFile ) return SQLITE_NOMEM;
2496 
2497     iIn = 5;
2498 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2499     if( strncmp(zUri+5, "///", 3)==0 ){
2500       iIn = 7;
2501       /* The following condition causes URIs with five leading / characters
2502       ** like file://///host/path to be converted into UNCs like //host/path.
2503       ** The correct URI for that UNC has only two or four leading / characters
2504       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2505       ** common error, we are told, so we handle it as a special case. */
2506       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2507     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2508       iIn = 16;
2509     }
2510 #else
2511     /* Discard the scheme and authority segments of the URI. */
2512     if( zUri[5]=='/' && zUri[6]=='/' ){
2513       iIn = 7;
2514       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2515       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2516         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2517             iIn-7, &zUri[7]);
2518         rc = SQLITE_ERROR;
2519         goto parse_uri_out;
2520       }
2521     }
2522 #endif
2523 
2524     /* Copy the filename and any query parameters into the zFile buffer.
2525     ** Decode %HH escape codes along the way.
2526     **
2527     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2528     ** on the parsing context. As follows:
2529     **
2530     **   0: Parsing file-name.
2531     **   1: Parsing name section of a name=value query parameter.
2532     **   2: Parsing value section of a name=value query parameter.
2533     */
2534     eState = 0;
2535     while( (c = zUri[iIn])!=0 && c!='#' ){
2536       iIn++;
2537       if( c=='%'
2538        && sqlite3Isxdigit(zUri[iIn])
2539        && sqlite3Isxdigit(zUri[iIn+1])
2540       ){
2541         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2542         octet += sqlite3HexToInt(zUri[iIn++]);
2543 
2544         assert( octet>=0 && octet<256 );
2545         if( octet==0 ){
2546           /* This branch is taken when "%00" appears within the URI. In this
2547           ** case we ignore all text in the remainder of the path, name or
2548           ** value currently being parsed. So ignore the current character
2549           ** and skip to the next "?", "=" or "&", as appropriate. */
2550           while( (c = zUri[iIn])!=0 && c!='#'
2551               && (eState!=0 || c!='?')
2552               && (eState!=1 || (c!='=' && c!='&'))
2553               && (eState!=2 || c!='&')
2554           ){
2555             iIn++;
2556           }
2557           continue;
2558         }
2559         c = octet;
2560       }else if( eState==1 && (c=='&' || c=='=') ){
2561         if( zFile[iOut-1]==0 ){
2562           /* An empty option name. Ignore this option altogether. */
2563           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2564           continue;
2565         }
2566         if( c=='&' ){
2567           zFile[iOut++] = '\0';
2568         }else{
2569           eState = 2;
2570         }
2571         c = 0;
2572       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2573         c = 0;
2574         eState = 1;
2575       }
2576       zFile[iOut++] = c;
2577     }
2578     if( eState==1 ) zFile[iOut++] = '\0';
2579     zFile[iOut++] = '\0';
2580     zFile[iOut++] = '\0';
2581 
2582     /* Check if there were any options specified that should be interpreted
2583     ** here. Options that are interpreted here include "vfs" and those that
2584     ** correspond to flags that may be passed to the sqlite3_open_v2()
2585     ** method. */
2586     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2587     while( zOpt[0] ){
2588       int nOpt = sqlite3Strlen30(zOpt);
2589       char *zVal = &zOpt[nOpt+1];
2590       int nVal = sqlite3Strlen30(zVal);
2591 
2592       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2593         zVfs = zVal;
2594       }else{
2595         struct OpenMode {
2596           const char *z;
2597           int mode;
2598         } *aMode = 0;
2599         char *zModeType = 0;
2600         int mask = 0;
2601         int limit = 0;
2602 
2603         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2604           static struct OpenMode aCacheMode[] = {
2605             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2606             { "private", SQLITE_OPEN_PRIVATECACHE },
2607             { 0, 0 }
2608           };
2609 
2610           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2611           aMode = aCacheMode;
2612           limit = mask;
2613           zModeType = "cache";
2614         }
2615         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2616           static struct OpenMode aOpenMode[] = {
2617             { "ro",  SQLITE_OPEN_READONLY },
2618             { "rw",  SQLITE_OPEN_READWRITE },
2619             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2620             { "memory", SQLITE_OPEN_MEMORY },
2621             { 0, 0 }
2622           };
2623 
2624           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2625                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2626           aMode = aOpenMode;
2627           limit = mask & flags;
2628           zModeType = "access";
2629         }
2630 
2631         if( aMode ){
2632           int i;
2633           int mode = 0;
2634           for(i=0; aMode[i].z; i++){
2635             const char *z = aMode[i].z;
2636             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2637               mode = aMode[i].mode;
2638               break;
2639             }
2640           }
2641           if( mode==0 ){
2642             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2643             rc = SQLITE_ERROR;
2644             goto parse_uri_out;
2645           }
2646           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2647             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2648                                         zModeType, zVal);
2649             rc = SQLITE_PERM;
2650             goto parse_uri_out;
2651           }
2652           flags = (flags & ~mask) | mode;
2653         }
2654       }
2655 
2656       zOpt = &zVal[nVal+1];
2657     }
2658 
2659   }else{
2660     zFile = sqlite3_malloc64(nUri+2);
2661     if( !zFile ) return SQLITE_NOMEM;
2662     memcpy(zFile, zUri, nUri);
2663     zFile[nUri] = '\0';
2664     zFile[nUri+1] = '\0';
2665     flags &= ~SQLITE_OPEN_URI;
2666   }
2667 
2668   *ppVfs = sqlite3_vfs_find(zVfs);
2669   if( *ppVfs==0 ){
2670     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2671     rc = SQLITE_ERROR;
2672   }
2673  parse_uri_out:
2674   if( rc!=SQLITE_OK ){
2675     sqlite3_free(zFile);
2676     zFile = 0;
2677   }
2678   *pFlags = flags;
2679   *pzFile = zFile;
2680   return rc;
2681 }
2682 
2683 
2684 /*
2685 ** This routine does the work of opening a database on behalf of
2686 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2687 ** is UTF-8 encoded.
2688 */
2689 static int openDatabase(
2690   const char *zFilename, /* Database filename UTF-8 encoded */
2691   sqlite3 **ppDb,        /* OUT: Returned database handle */
2692   unsigned int flags,    /* Operational flags */
2693   const char *zVfs       /* Name of the VFS to use */
2694 ){
2695   sqlite3 *db;                    /* Store allocated handle here */
2696   int rc;                         /* Return code */
2697   int isThreadsafe;               /* True for threadsafe connections */
2698   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2699   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2700 
2701 #ifdef SQLITE_ENABLE_API_ARMOR
2702   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2703 #endif
2704   *ppDb = 0;
2705 #ifndef SQLITE_OMIT_AUTOINIT
2706   rc = sqlite3_initialize();
2707   if( rc ) return rc;
2708 #endif
2709 
2710   /* Only allow sensible combinations of bits in the flags argument.
2711   ** Throw an error if any non-sense combination is used.  If we
2712   ** do not block illegal combinations here, it could trigger
2713   ** assert() statements in deeper layers.  Sensible combinations
2714   ** are:
2715   **
2716   **  1:  SQLITE_OPEN_READONLY
2717   **  2:  SQLITE_OPEN_READWRITE
2718   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2719   */
2720   assert( SQLITE_OPEN_READONLY  == 0x01 );
2721   assert( SQLITE_OPEN_READWRITE == 0x02 );
2722   assert( SQLITE_OPEN_CREATE    == 0x04 );
2723   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2724   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2725   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2726   if( ((1<<(flags&7)) & 0x46)==0 ){
2727     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2728   }
2729 
2730   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2731     isThreadsafe = 0;
2732   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2733     isThreadsafe = 0;
2734   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2735     isThreadsafe = 1;
2736   }else{
2737     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2738   }
2739   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2740     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2741   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2742     flags |= SQLITE_OPEN_SHAREDCACHE;
2743   }
2744 
2745   /* Remove harmful bits from the flags parameter
2746   **
2747   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2748   ** dealt with in the previous code block.  Besides these, the only
2749   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2750   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2751   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2752   ** off all other flags.
2753   */
2754   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2755                SQLITE_OPEN_EXCLUSIVE |
2756                SQLITE_OPEN_MAIN_DB |
2757                SQLITE_OPEN_TEMP_DB |
2758                SQLITE_OPEN_TRANSIENT_DB |
2759                SQLITE_OPEN_MAIN_JOURNAL |
2760                SQLITE_OPEN_TEMP_JOURNAL |
2761                SQLITE_OPEN_SUBJOURNAL |
2762                SQLITE_OPEN_MASTER_JOURNAL |
2763                SQLITE_OPEN_NOMUTEX |
2764                SQLITE_OPEN_FULLMUTEX |
2765                SQLITE_OPEN_WAL
2766              );
2767 
2768   /* Allocate the sqlite data structure */
2769   db = sqlite3MallocZero( sizeof(sqlite3) );
2770   if( db==0 ) goto opendb_out;
2771   if( isThreadsafe ){
2772     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2773     if( db->mutex==0 ){
2774       sqlite3_free(db);
2775       db = 0;
2776       goto opendb_out;
2777     }
2778   }
2779   sqlite3_mutex_enter(db->mutex);
2780   db->errMask = 0xff;
2781   db->nDb = 2;
2782   db->magic = SQLITE_MAGIC_BUSY;
2783   db->aDb = db->aDbStatic;
2784 
2785   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2786   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2787   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2788   db->autoCommit = 1;
2789   db->nextAutovac = -1;
2790   db->szMmap = sqlite3GlobalConfig.szMmap;
2791   db->nextPagesize = 0;
2792   db->nMaxSorterMmap = 0x7FFFFFFF;
2793   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2794 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2795                  | SQLITE_AutoIndex
2796 #endif
2797 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2798                  | SQLITE_CkptFullFSync
2799 #endif
2800 #if SQLITE_DEFAULT_FILE_FORMAT<4
2801                  | SQLITE_LegacyFileFmt
2802 #endif
2803 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2804                  | SQLITE_LoadExtension
2805 #endif
2806 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2807                  | SQLITE_RecTriggers
2808 #endif
2809 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2810                  | SQLITE_ForeignKeys
2811 #endif
2812 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2813                  | SQLITE_ReverseOrder
2814 #endif
2815 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2816                  | SQLITE_CellSizeCk
2817 #endif
2818       ;
2819   sqlite3HashInit(&db->aCollSeq);
2820 #ifndef SQLITE_OMIT_VIRTUALTABLE
2821   sqlite3HashInit(&db->aModule);
2822 #endif
2823 
2824   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2825   ** and UTF-16, so add a version for each to avoid any unnecessary
2826   ** conversions. The only error that can occur here is a malloc() failure.
2827   **
2828   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2829   ** functions:
2830   */
2831   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2832   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2833   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2834   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2835   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2836   if( db->mallocFailed ){
2837     goto opendb_out;
2838   }
2839   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2840   ** strings is BINARY.
2841   */
2842   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2843   assert( db->pDfltColl!=0 );
2844 
2845   /* Parse the filename/URI argument. */
2846   db->openFlags = flags;
2847   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2848   if( rc!=SQLITE_OK ){
2849     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2850     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2851     sqlite3_free(zErrMsg);
2852     goto opendb_out;
2853   }
2854 
2855   /* Open the backend database driver */
2856   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2857                         flags | SQLITE_OPEN_MAIN_DB);
2858   if( rc!=SQLITE_OK ){
2859     if( rc==SQLITE_IOERR_NOMEM ){
2860       rc = SQLITE_NOMEM;
2861     }
2862     sqlite3Error(db, rc);
2863     goto opendb_out;
2864   }
2865   sqlite3BtreeEnter(db->aDb[0].pBt);
2866   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2867   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2868   sqlite3BtreeLeave(db->aDb[0].pBt);
2869   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2870 
2871   /* The default safety_level for the main database is 'full'; for the temp
2872   ** database it is 'NONE'. This matches the pager layer defaults.
2873   */
2874   db->aDb[0].zName = "main";
2875   db->aDb[0].safety_level = 3;
2876   db->aDb[1].zName = "temp";
2877   db->aDb[1].safety_level = 1;
2878 
2879   db->magic = SQLITE_MAGIC_OPEN;
2880   if( db->mallocFailed ){
2881     goto opendb_out;
2882   }
2883 
2884   /* Register all built-in functions, but do not attempt to read the
2885   ** database schema yet. This is delayed until the first time the database
2886   ** is accessed.
2887   */
2888   sqlite3Error(db, SQLITE_OK);
2889   sqlite3RegisterBuiltinFunctions(db);
2890 
2891   /* Load automatic extensions - extensions that have been registered
2892   ** using the sqlite3_automatic_extension() API.
2893   */
2894   rc = sqlite3_errcode(db);
2895   if( rc==SQLITE_OK ){
2896     sqlite3AutoLoadExtensions(db);
2897     rc = sqlite3_errcode(db);
2898     if( rc!=SQLITE_OK ){
2899       goto opendb_out;
2900     }
2901   }
2902 
2903 #ifdef SQLITE_ENABLE_FTS1
2904   if( !db->mallocFailed ){
2905     extern int sqlite3Fts1Init(sqlite3*);
2906     rc = sqlite3Fts1Init(db);
2907   }
2908 #endif
2909 
2910 #ifdef SQLITE_ENABLE_FTS2
2911   if( !db->mallocFailed && rc==SQLITE_OK ){
2912     extern int sqlite3Fts2Init(sqlite3*);
2913     rc = sqlite3Fts2Init(db);
2914   }
2915 #endif
2916 
2917 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
2918   if( !db->mallocFailed && rc==SQLITE_OK ){
2919     rc = sqlite3Fts3Init(db);
2920   }
2921 #endif
2922 
2923 #ifdef SQLITE_ENABLE_FTS5
2924   if( !db->mallocFailed && rc==SQLITE_OK ){
2925     rc = sqlite3Fts5Init(db);
2926   }
2927 #endif
2928 
2929 #ifdef SQLITE_ENABLE_ICU
2930   if( !db->mallocFailed && rc==SQLITE_OK ){
2931     rc = sqlite3IcuInit(db);
2932   }
2933 #endif
2934 
2935 #ifdef SQLITE_ENABLE_RTREE
2936   if( !db->mallocFailed && rc==SQLITE_OK){
2937     rc = sqlite3RtreeInit(db);
2938   }
2939 #endif
2940 
2941 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
2942   if( !db->mallocFailed && rc==SQLITE_OK){
2943     rc = sqlite3DbstatRegister(db);
2944   }
2945 #endif
2946 
2947 #ifdef SQLITE_ENABLE_JSON1
2948   if( !db->mallocFailed && rc==SQLITE_OK){
2949     rc = sqlite3Json1Init(db);
2950   }
2951 #endif
2952 
2953   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2954   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2955   ** mode.  Doing nothing at all also makes NORMAL the default.
2956   */
2957 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2958   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2959   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2960                           SQLITE_DEFAULT_LOCKING_MODE);
2961 #endif
2962 
2963   if( rc ) sqlite3Error(db, rc);
2964 
2965   /* Enable the lookaside-malloc subsystem */
2966   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2967                         sqlite3GlobalConfig.nLookaside);
2968 
2969   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2970 
2971 opendb_out:
2972   if( db ){
2973     assert( db->mutex!=0 || isThreadsafe==0
2974            || sqlite3GlobalConfig.bFullMutex==0 );
2975     sqlite3_mutex_leave(db->mutex);
2976   }
2977   rc = sqlite3_errcode(db);
2978   assert( db!=0 || rc==SQLITE_NOMEM );
2979   if( rc==SQLITE_NOMEM ){
2980     sqlite3_close(db);
2981     db = 0;
2982   }else if( rc!=SQLITE_OK ){
2983     db->magic = SQLITE_MAGIC_SICK;
2984   }
2985   *ppDb = db;
2986 #ifdef SQLITE_ENABLE_SQLLOG
2987   if( sqlite3GlobalConfig.xSqllog ){
2988     /* Opening a db handle. Fourth parameter is passed 0. */
2989     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2990     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2991   }
2992 #endif
2993 #if defined(SQLITE_HAS_CODEC)
2994   if( rc==SQLITE_OK ){
2995     const char *zHexKey = sqlite3_uri_parameter(zOpen, "hexkey");
2996     if( zHexKey && zHexKey[0] ){
2997       u8 iByte;
2998       int i;
2999       char zKey[40];
3000       for(i=0, iByte=0; i<sizeof(zKey)*2 && sqlite3Isxdigit(zHexKey[i]); i++){
3001         iByte = (iByte<<4) + sqlite3HexToInt(zHexKey[i]);
3002         if( (i&1)!=0 ) zKey[i/2] = iByte;
3003       }
3004       sqlite3_key_v2(db, 0, zKey, i/2);
3005     }
3006   }
3007 #endif
3008   sqlite3_free(zOpen);
3009   return rc & 0xff;
3010 }
3011 
3012 /*
3013 ** Open a new database handle.
3014 */
3015 int sqlite3_open(
3016   const char *zFilename,
3017   sqlite3 **ppDb
3018 ){
3019   return openDatabase(zFilename, ppDb,
3020                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3021 }
3022 int sqlite3_open_v2(
3023   const char *filename,   /* Database filename (UTF-8) */
3024   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3025   int flags,              /* Flags */
3026   const char *zVfs        /* Name of VFS module to use */
3027 ){
3028   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3029 }
3030 
3031 #ifndef SQLITE_OMIT_UTF16
3032 /*
3033 ** Open a new database handle.
3034 */
3035 int sqlite3_open16(
3036   const void *zFilename,
3037   sqlite3 **ppDb
3038 ){
3039   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3040   sqlite3_value *pVal;
3041   int rc;
3042 
3043 #ifdef SQLITE_ENABLE_API_ARMOR
3044   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3045 #endif
3046   *ppDb = 0;
3047 #ifndef SQLITE_OMIT_AUTOINIT
3048   rc = sqlite3_initialize();
3049   if( rc ) return rc;
3050 #endif
3051   if( zFilename==0 ) zFilename = "\000\000";
3052   pVal = sqlite3ValueNew(0);
3053   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3054   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3055   if( zFilename8 ){
3056     rc = openDatabase(zFilename8, ppDb,
3057                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3058     assert( *ppDb || rc==SQLITE_NOMEM );
3059     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3060       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3061     }
3062   }else{
3063     rc = SQLITE_NOMEM;
3064   }
3065   sqlite3ValueFree(pVal);
3066 
3067   return rc & 0xff;
3068 }
3069 #endif /* SQLITE_OMIT_UTF16 */
3070 
3071 /*
3072 ** Register a new collation sequence with the database handle db.
3073 */
3074 int sqlite3_create_collation(
3075   sqlite3* db,
3076   const char *zName,
3077   int enc,
3078   void* pCtx,
3079   int(*xCompare)(void*,int,const void*,int,const void*)
3080 ){
3081   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3082 }
3083 
3084 /*
3085 ** Register a new collation sequence with the database handle db.
3086 */
3087 int sqlite3_create_collation_v2(
3088   sqlite3* db,
3089   const char *zName,
3090   int enc,
3091   void* pCtx,
3092   int(*xCompare)(void*,int,const void*,int,const void*),
3093   void(*xDel)(void*)
3094 ){
3095   int rc;
3096 
3097 #ifdef SQLITE_ENABLE_API_ARMOR
3098   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3099 #endif
3100   sqlite3_mutex_enter(db->mutex);
3101   assert( !db->mallocFailed );
3102   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3103   rc = sqlite3ApiExit(db, rc);
3104   sqlite3_mutex_leave(db->mutex);
3105   return rc;
3106 }
3107 
3108 #ifndef SQLITE_OMIT_UTF16
3109 /*
3110 ** Register a new collation sequence with the database handle db.
3111 */
3112 int sqlite3_create_collation16(
3113   sqlite3* db,
3114   const void *zName,
3115   int enc,
3116   void* pCtx,
3117   int(*xCompare)(void*,int,const void*,int,const void*)
3118 ){
3119   int rc = SQLITE_OK;
3120   char *zName8;
3121 
3122 #ifdef SQLITE_ENABLE_API_ARMOR
3123   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3124 #endif
3125   sqlite3_mutex_enter(db->mutex);
3126   assert( !db->mallocFailed );
3127   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3128   if( zName8 ){
3129     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3130     sqlite3DbFree(db, zName8);
3131   }
3132   rc = sqlite3ApiExit(db, rc);
3133   sqlite3_mutex_leave(db->mutex);
3134   return rc;
3135 }
3136 #endif /* SQLITE_OMIT_UTF16 */
3137 
3138 /*
3139 ** Register a collation sequence factory callback with the database handle
3140 ** db. Replace any previously installed collation sequence factory.
3141 */
3142 int sqlite3_collation_needed(
3143   sqlite3 *db,
3144   void *pCollNeededArg,
3145   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3146 ){
3147 #ifdef SQLITE_ENABLE_API_ARMOR
3148   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3149 #endif
3150   sqlite3_mutex_enter(db->mutex);
3151   db->xCollNeeded = xCollNeeded;
3152   db->xCollNeeded16 = 0;
3153   db->pCollNeededArg = pCollNeededArg;
3154   sqlite3_mutex_leave(db->mutex);
3155   return SQLITE_OK;
3156 }
3157 
3158 #ifndef SQLITE_OMIT_UTF16
3159 /*
3160 ** Register a collation sequence factory callback with the database handle
3161 ** db. Replace any previously installed collation sequence factory.
3162 */
3163 int sqlite3_collation_needed16(
3164   sqlite3 *db,
3165   void *pCollNeededArg,
3166   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3167 ){
3168 #ifdef SQLITE_ENABLE_API_ARMOR
3169   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3170 #endif
3171   sqlite3_mutex_enter(db->mutex);
3172   db->xCollNeeded = 0;
3173   db->xCollNeeded16 = xCollNeeded16;
3174   db->pCollNeededArg = pCollNeededArg;
3175   sqlite3_mutex_leave(db->mutex);
3176   return SQLITE_OK;
3177 }
3178 #endif /* SQLITE_OMIT_UTF16 */
3179 
3180 #ifndef SQLITE_OMIT_DEPRECATED
3181 /*
3182 ** This function is now an anachronism. It used to be used to recover from a
3183 ** malloc() failure, but SQLite now does this automatically.
3184 */
3185 int sqlite3_global_recover(void){
3186   return SQLITE_OK;
3187 }
3188 #endif
3189 
3190 /*
3191 ** Test to see whether or not the database connection is in autocommit
3192 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3193 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3194 ** by the next COMMIT or ROLLBACK.
3195 */
3196 int sqlite3_get_autocommit(sqlite3 *db){
3197 #ifdef SQLITE_ENABLE_API_ARMOR
3198   if( !sqlite3SafetyCheckOk(db) ){
3199     (void)SQLITE_MISUSE_BKPT;
3200     return 0;
3201   }
3202 #endif
3203   return db->autoCommit;
3204 }
3205 
3206 /*
3207 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3208 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
3209 ** constants.  They serve two purposes:
3210 **
3211 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3212 **       to detect when version error conditions occurs.
3213 **
3214 **   2.  Invoke sqlite3_log() to provide the source code location where
3215 **       a low-level error is first detected.
3216 */
3217 int sqlite3CorruptError(int lineno){
3218   testcase( sqlite3GlobalConfig.xLog!=0 );
3219   sqlite3_log(SQLITE_CORRUPT,
3220               "database corruption at line %d of [%.10s]",
3221               lineno, 20+sqlite3_sourceid());
3222   return SQLITE_CORRUPT;
3223 }
3224 int sqlite3MisuseError(int lineno){
3225   testcase( sqlite3GlobalConfig.xLog!=0 );
3226   sqlite3_log(SQLITE_MISUSE,
3227               "misuse at line %d of [%.10s]",
3228               lineno, 20+sqlite3_sourceid());
3229   return SQLITE_MISUSE;
3230 }
3231 int sqlite3CantopenError(int lineno){
3232   testcase( sqlite3GlobalConfig.xLog!=0 );
3233   sqlite3_log(SQLITE_CANTOPEN,
3234               "cannot open file at line %d of [%.10s]",
3235               lineno, 20+sqlite3_sourceid());
3236   return SQLITE_CANTOPEN;
3237 }
3238 
3239 
3240 #ifndef SQLITE_OMIT_DEPRECATED
3241 /*
3242 ** This is a convenience routine that makes sure that all thread-specific
3243 ** data for this thread has been deallocated.
3244 **
3245 ** SQLite no longer uses thread-specific data so this routine is now a
3246 ** no-op.  It is retained for historical compatibility.
3247 */
3248 void sqlite3_thread_cleanup(void){
3249 }
3250 #endif
3251 
3252 /*
3253 ** Return meta information about a specific column of a database table.
3254 ** See comment in sqlite3.h (sqlite.h.in) for details.
3255 */
3256 int sqlite3_table_column_metadata(
3257   sqlite3 *db,                /* Connection handle */
3258   const char *zDbName,        /* Database name or NULL */
3259   const char *zTableName,     /* Table name */
3260   const char *zColumnName,    /* Column name */
3261   char const **pzDataType,    /* OUTPUT: Declared data type */
3262   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3263   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3264   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3265   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3266 ){
3267   int rc;
3268   char *zErrMsg = 0;
3269   Table *pTab = 0;
3270   Column *pCol = 0;
3271   int iCol = 0;
3272   char const *zDataType = 0;
3273   char const *zCollSeq = 0;
3274   int notnull = 0;
3275   int primarykey = 0;
3276   int autoinc = 0;
3277 
3278 
3279 #ifdef SQLITE_ENABLE_API_ARMOR
3280   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3281     return SQLITE_MISUSE_BKPT;
3282   }
3283 #endif
3284 
3285   /* Ensure the database schema has been loaded */
3286   sqlite3_mutex_enter(db->mutex);
3287   sqlite3BtreeEnterAll(db);
3288   rc = sqlite3Init(db, &zErrMsg);
3289   if( SQLITE_OK!=rc ){
3290     goto error_out;
3291   }
3292 
3293   /* Locate the table in question */
3294   pTab = sqlite3FindTable(db, zTableName, zDbName);
3295   if( !pTab || pTab->pSelect ){
3296     pTab = 0;
3297     goto error_out;
3298   }
3299 
3300   /* Find the column for which info is requested */
3301   if( zColumnName==0 ){
3302     /* Query for existance of table only */
3303   }else{
3304     for(iCol=0; iCol<pTab->nCol; iCol++){
3305       pCol = &pTab->aCol[iCol];
3306       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3307         break;
3308       }
3309     }
3310     if( iCol==pTab->nCol ){
3311       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3312         iCol = pTab->iPKey;
3313         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3314       }else{
3315         pTab = 0;
3316         goto error_out;
3317       }
3318     }
3319   }
3320 
3321   /* The following block stores the meta information that will be returned
3322   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3323   ** and autoinc. At this point there are two possibilities:
3324   **
3325   **     1. The specified column name was rowid", "oid" or "_rowid_"
3326   **        and there is no explicitly declared IPK column.
3327   **
3328   **     2. The table is not a view and the column name identified an
3329   **        explicitly declared column. Copy meta information from *pCol.
3330   */
3331   if( pCol ){
3332     zDataType = pCol->zType;
3333     zCollSeq = pCol->zColl;
3334     notnull = pCol->notNull!=0;
3335     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3336     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3337   }else{
3338     zDataType = "INTEGER";
3339     primarykey = 1;
3340   }
3341   if( !zCollSeq ){
3342     zCollSeq = sqlite3StrBINARY;
3343   }
3344 
3345 error_out:
3346   sqlite3BtreeLeaveAll(db);
3347 
3348   /* Whether the function call succeeded or failed, set the output parameters
3349   ** to whatever their local counterparts contain. If an error did occur,
3350   ** this has the effect of zeroing all output parameters.
3351   */
3352   if( pzDataType ) *pzDataType = zDataType;
3353   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3354   if( pNotNull ) *pNotNull = notnull;
3355   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3356   if( pAutoinc ) *pAutoinc = autoinc;
3357 
3358   if( SQLITE_OK==rc && !pTab ){
3359     sqlite3DbFree(db, zErrMsg);
3360     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3361         zColumnName);
3362     rc = SQLITE_ERROR;
3363   }
3364   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3365   sqlite3DbFree(db, zErrMsg);
3366   rc = sqlite3ApiExit(db, rc);
3367   sqlite3_mutex_leave(db->mutex);
3368   return rc;
3369 }
3370 
3371 /*
3372 ** Sleep for a little while.  Return the amount of time slept.
3373 */
3374 int sqlite3_sleep(int ms){
3375   sqlite3_vfs *pVfs;
3376   int rc;
3377   pVfs = sqlite3_vfs_find(0);
3378   if( pVfs==0 ) return 0;
3379 
3380   /* This function works in milliseconds, but the underlying OsSleep()
3381   ** API uses microseconds. Hence the 1000's.
3382   */
3383   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3384   return rc;
3385 }
3386 
3387 /*
3388 ** Enable or disable the extended result codes.
3389 */
3390 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3391 #ifdef SQLITE_ENABLE_API_ARMOR
3392   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3393 #endif
3394   sqlite3_mutex_enter(db->mutex);
3395   db->errMask = onoff ? 0xffffffff : 0xff;
3396   sqlite3_mutex_leave(db->mutex);
3397   return SQLITE_OK;
3398 }
3399 
3400 /*
3401 ** Invoke the xFileControl method on a particular database.
3402 */
3403 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3404   int rc = SQLITE_ERROR;
3405   Btree *pBtree;
3406 
3407 #ifdef SQLITE_ENABLE_API_ARMOR
3408   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3409 #endif
3410   sqlite3_mutex_enter(db->mutex);
3411   pBtree = sqlite3DbNameToBtree(db, zDbName);
3412   if( pBtree ){
3413     Pager *pPager;
3414     sqlite3_file *fd;
3415     sqlite3BtreeEnter(pBtree);
3416     pPager = sqlite3BtreePager(pBtree);
3417     assert( pPager!=0 );
3418     fd = sqlite3PagerFile(pPager);
3419     assert( fd!=0 );
3420     if( op==SQLITE_FCNTL_FILE_POINTER ){
3421       *(sqlite3_file**)pArg = fd;
3422       rc = SQLITE_OK;
3423     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3424       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3425       rc = SQLITE_OK;
3426     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3427       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3428       rc = SQLITE_OK;
3429     }else if( fd->pMethods ){
3430       rc = sqlite3OsFileControl(fd, op, pArg);
3431     }else{
3432       rc = SQLITE_NOTFOUND;
3433     }
3434     sqlite3BtreeLeave(pBtree);
3435   }
3436   sqlite3_mutex_leave(db->mutex);
3437   return rc;
3438 }
3439 
3440 /*
3441 ** Interface to the testing logic.
3442 */
3443 int sqlite3_test_control(int op, ...){
3444   int rc = 0;
3445 #ifdef SQLITE_OMIT_BUILTIN_TEST
3446   UNUSED_PARAMETER(op);
3447 #else
3448   va_list ap;
3449   va_start(ap, op);
3450   switch( op ){
3451 
3452     /*
3453     ** Save the current state of the PRNG.
3454     */
3455     case SQLITE_TESTCTRL_PRNG_SAVE: {
3456       sqlite3PrngSaveState();
3457       break;
3458     }
3459 
3460     /*
3461     ** Restore the state of the PRNG to the last state saved using
3462     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3463     ** this verb acts like PRNG_RESET.
3464     */
3465     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3466       sqlite3PrngRestoreState();
3467       break;
3468     }
3469 
3470     /*
3471     ** Reset the PRNG back to its uninitialized state.  The next call
3472     ** to sqlite3_randomness() will reseed the PRNG using a single call
3473     ** to the xRandomness method of the default VFS.
3474     */
3475     case SQLITE_TESTCTRL_PRNG_RESET: {
3476       sqlite3_randomness(0,0);
3477       break;
3478     }
3479 
3480     /*
3481     **  sqlite3_test_control(BITVEC_TEST, size, program)
3482     **
3483     ** Run a test against a Bitvec object of size.  The program argument
3484     ** is an array of integers that defines the test.  Return -1 on a
3485     ** memory allocation error, 0 on success, or non-zero for an error.
3486     ** See the sqlite3BitvecBuiltinTest() for additional information.
3487     */
3488     case SQLITE_TESTCTRL_BITVEC_TEST: {
3489       int sz = va_arg(ap, int);
3490       int *aProg = va_arg(ap, int*);
3491       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3492       break;
3493     }
3494 
3495     /*
3496     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3497     **
3498     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3499     ** if xCallback is not NULL.
3500     **
3501     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3502     ** is called immediately after installing the new callback and the return
3503     ** value from sqlite3FaultSim(0) becomes the return from
3504     ** sqlite3_test_control().
3505     */
3506     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3507       /* MSVC is picky about pulling func ptrs from va lists.
3508       ** http://support.microsoft.com/kb/47961
3509       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3510       */
3511       typedef int(*TESTCALLBACKFUNC_t)(int);
3512       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3513       rc = sqlite3FaultSim(0);
3514       break;
3515     }
3516 
3517     /*
3518     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3519     **
3520     ** Register hooks to call to indicate which malloc() failures
3521     ** are benign.
3522     */
3523     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3524       typedef void (*void_function)(void);
3525       void_function xBenignBegin;
3526       void_function xBenignEnd;
3527       xBenignBegin = va_arg(ap, void_function);
3528       xBenignEnd = va_arg(ap, void_function);
3529       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3530       break;
3531     }
3532 
3533     /*
3534     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3535     **
3536     ** Set the PENDING byte to the value in the argument, if X>0.
3537     ** Make no changes if X==0.  Return the value of the pending byte
3538     ** as it existing before this routine was called.
3539     **
3540     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3541     ** an incompatible database file format.  Changing the PENDING byte
3542     ** while any database connection is open results in undefined and
3543     ** deleterious behavior.
3544     */
3545     case SQLITE_TESTCTRL_PENDING_BYTE: {
3546       rc = PENDING_BYTE;
3547 #ifndef SQLITE_OMIT_WSD
3548       {
3549         unsigned int newVal = va_arg(ap, unsigned int);
3550         if( newVal ) sqlite3PendingByte = newVal;
3551       }
3552 #endif
3553       break;
3554     }
3555 
3556     /*
3557     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3558     **
3559     ** This action provides a run-time test to see whether or not
3560     ** assert() was enabled at compile-time.  If X is true and assert()
3561     ** is enabled, then the return value is true.  If X is true and
3562     ** assert() is disabled, then the return value is zero.  If X is
3563     ** false and assert() is enabled, then the assertion fires and the
3564     ** process aborts.  If X is false and assert() is disabled, then the
3565     ** return value is zero.
3566     */
3567     case SQLITE_TESTCTRL_ASSERT: {
3568       volatile int x = 0;
3569       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3570       rc = x;
3571       break;
3572     }
3573 
3574 
3575     /*
3576     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3577     **
3578     ** This action provides a run-time test to see how the ALWAYS and
3579     ** NEVER macros were defined at compile-time.
3580     **
3581     ** The return value is ALWAYS(X).
3582     **
3583     ** The recommended test is X==2.  If the return value is 2, that means
3584     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3585     ** default setting.  If the return value is 1, then ALWAYS() is either
3586     ** hard-coded to true or else it asserts if its argument is false.
3587     ** The first behavior (hard-coded to true) is the case if
3588     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3589     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3590     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3591     **
3592     ** The run-time test procedure might look something like this:
3593     **
3594     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3595     **      // ALWAYS() and NEVER() are no-op pass-through macros
3596     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3597     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3598     **    }else{
3599     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3600     **    }
3601     */
3602     case SQLITE_TESTCTRL_ALWAYS: {
3603       int x = va_arg(ap,int);
3604       rc = ALWAYS(x);
3605       break;
3606     }
3607 
3608     /*
3609     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3610     **
3611     ** The integer returned reveals the byte-order of the computer on which
3612     ** SQLite is running:
3613     **
3614     **       1     big-endian,    determined at run-time
3615     **      10     little-endian, determined at run-time
3616     **  432101     big-endian,    determined at compile-time
3617     **  123410     little-endian, determined at compile-time
3618     */
3619     case SQLITE_TESTCTRL_BYTEORDER: {
3620       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3621       break;
3622     }
3623 
3624     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3625     **
3626     ** Set the nReserve size to N for the main database on the database
3627     ** connection db.
3628     */
3629     case SQLITE_TESTCTRL_RESERVE: {
3630       sqlite3 *db = va_arg(ap, sqlite3*);
3631       int x = va_arg(ap,int);
3632       sqlite3_mutex_enter(db->mutex);
3633       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3634       sqlite3_mutex_leave(db->mutex);
3635       break;
3636     }
3637 
3638     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3639     **
3640     ** Enable or disable various optimizations for testing purposes.  The
3641     ** argument N is a bitmask of optimizations to be disabled.  For normal
3642     ** operation N should be 0.  The idea is that a test program (like the
3643     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3644     ** with various optimizations disabled to verify that the same answer
3645     ** is obtained in every case.
3646     */
3647     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3648       sqlite3 *db = va_arg(ap, sqlite3*);
3649       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3650       break;
3651     }
3652 
3653 #ifdef SQLITE_N_KEYWORD
3654     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3655     **
3656     ** If zWord is a keyword recognized by the parser, then return the
3657     ** number of keywords.  Or if zWord is not a keyword, return 0.
3658     **
3659     ** This test feature is only available in the amalgamation since
3660     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3661     ** is built using separate source files.
3662     */
3663     case SQLITE_TESTCTRL_ISKEYWORD: {
3664       const char *zWord = va_arg(ap, const char*);
3665       int n = sqlite3Strlen30(zWord);
3666       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3667       break;
3668     }
3669 #endif
3670 
3671     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3672     **
3673     ** Pass pFree into sqlite3ScratchFree().
3674     ** If sz>0 then allocate a scratch buffer into pNew.
3675     */
3676     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3677       void *pFree, **ppNew;
3678       int sz;
3679       sz = va_arg(ap, int);
3680       ppNew = va_arg(ap, void**);
3681       pFree = va_arg(ap, void*);
3682       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3683       sqlite3ScratchFree(pFree);
3684       break;
3685     }
3686 
3687     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3688     **
3689     ** If parameter onoff is non-zero, configure the wrappers so that all
3690     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3691     ** undo this setting.
3692     */
3693     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3694       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3695       break;
3696     }
3697 
3698     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3699     **
3700     ** Set or clear a flag that indicates that the database file is always well-
3701     ** formed and never corrupt.  This flag is clear by default, indicating that
3702     ** database files might have arbitrary corruption.  Setting the flag during
3703     ** testing causes certain assert() statements in the code to be activated
3704     ** that demonstrat invariants on well-formed database files.
3705     */
3706     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3707       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3708       break;
3709     }
3710 
3711 
3712     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3713     **
3714     ** Set the VDBE coverage callback function to xCallback with context
3715     ** pointer ptr.
3716     */
3717     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3718 #ifdef SQLITE_VDBE_COVERAGE
3719       typedef void (*branch_callback)(void*,int,u8,u8);
3720       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3721       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3722 #endif
3723       break;
3724     }
3725 
3726     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3727     case SQLITE_TESTCTRL_SORTER_MMAP: {
3728       sqlite3 *db = va_arg(ap, sqlite3*);
3729       db->nMaxSorterMmap = va_arg(ap, int);
3730       break;
3731     }
3732 
3733     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3734     **
3735     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3736     ** not.
3737     */
3738     case SQLITE_TESTCTRL_ISINIT: {
3739       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3740       break;
3741     }
3742 
3743     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3744     **
3745     ** This test control is used to create imposter tables.  "db" is a pointer
3746     ** to the database connection.  dbName is the database name (ex: "main" or
3747     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3748     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3749     ** table should connect.
3750     **
3751     ** Enable imposter mode only when the schema has already been parsed.  Then
3752     ** run a single CREATE TABLE statement to construct the imposter table in
3753     ** the parsed schema.  Then turn imposter mode back off again.
3754     **
3755     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3756     ** the schema to be reparsed the next time it is needed.  This has the
3757     ** effect of erasing all imposter tables.
3758     */
3759     case SQLITE_TESTCTRL_IMPOSTER: {
3760       sqlite3 *db = va_arg(ap, sqlite3*);
3761       sqlite3_mutex_enter(db->mutex);
3762       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3763       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3764       db->init.newTnum = va_arg(ap,int);
3765       if( db->init.busy==0 && db->init.newTnum>0 ){
3766         sqlite3ResetAllSchemasOfConnection(db);
3767       }
3768       sqlite3_mutex_leave(db->mutex);
3769       break;
3770     }
3771   }
3772   va_end(ap);
3773 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3774   return rc;
3775 }
3776 
3777 /*
3778 ** This is a utility routine, useful to VFS implementations, that checks
3779 ** to see if a database file was a URI that contained a specific query
3780 ** parameter, and if so obtains the value of the query parameter.
3781 **
3782 ** The zFilename argument is the filename pointer passed into the xOpen()
3783 ** method of a VFS implementation.  The zParam argument is the name of the
3784 ** query parameter we seek.  This routine returns the value of the zParam
3785 ** parameter if it exists.  If the parameter does not exist, this routine
3786 ** returns a NULL pointer.
3787 */
3788 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3789   if( zFilename==0 || zParam==0 ) return 0;
3790   zFilename += sqlite3Strlen30(zFilename) + 1;
3791   while( zFilename[0] ){
3792     int x = strcmp(zFilename, zParam);
3793     zFilename += sqlite3Strlen30(zFilename) + 1;
3794     if( x==0 ) return zFilename;
3795     zFilename += sqlite3Strlen30(zFilename) + 1;
3796   }
3797   return 0;
3798 }
3799 
3800 /*
3801 ** Return a boolean value for a query parameter.
3802 */
3803 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3804   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3805   bDflt = bDflt!=0;
3806   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3807 }
3808 
3809 /*
3810 ** Return a 64-bit integer value for a query parameter.
3811 */
3812 sqlite3_int64 sqlite3_uri_int64(
3813   const char *zFilename,    /* Filename as passed to xOpen */
3814   const char *zParam,       /* URI parameter sought */
3815   sqlite3_int64 bDflt       /* return if parameter is missing */
3816 ){
3817   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3818   sqlite3_int64 v;
3819   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3820     bDflt = v;
3821   }
3822   return bDflt;
3823 }
3824 
3825 /*
3826 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3827 */
3828 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3829   int i;
3830   for(i=0; i<db->nDb; i++){
3831     if( db->aDb[i].pBt
3832      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3833     ){
3834       return db->aDb[i].pBt;
3835     }
3836   }
3837   return 0;
3838 }
3839 
3840 /*
3841 ** Return the filename of the database associated with a database
3842 ** connection.
3843 */
3844 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3845   Btree *pBt;
3846 #ifdef SQLITE_ENABLE_API_ARMOR
3847   if( !sqlite3SafetyCheckOk(db) ){
3848     (void)SQLITE_MISUSE_BKPT;
3849     return 0;
3850   }
3851 #endif
3852   pBt = sqlite3DbNameToBtree(db, zDbName);
3853   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3854 }
3855 
3856 /*
3857 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3858 ** no such database exists.
3859 */
3860 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3861   Btree *pBt;
3862 #ifdef SQLITE_ENABLE_API_ARMOR
3863   if( !sqlite3SafetyCheckOk(db) ){
3864     (void)SQLITE_MISUSE_BKPT;
3865     return -1;
3866   }
3867 #endif
3868   pBt = sqlite3DbNameToBtree(db, zDbName);
3869   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3870 }
3871 
3872 #ifdef SQLITE_ENABLE_SNAPSHOT
3873 /*
3874 ** Obtain a snapshot handle for the snapshot of database zDb currently
3875 ** being read by handle db.
3876 */
3877 int sqlite3_snapshot_get(
3878   sqlite3 *db,
3879   const char *zDb,
3880   sqlite3_snapshot **ppSnapshot
3881 ){
3882   int rc = SQLITE_ERROR;
3883 #ifndef SQLITE_OMIT_WAL
3884   int iDb;
3885 
3886 #ifdef SQLITE_ENABLE_API_ARMOR
3887   if( !sqlite3SafetyCheckOk(db) ){
3888     return SQLITE_MISUSE_BKPT;
3889   }
3890 #endif
3891   sqlite3_mutex_enter(db->mutex);
3892 
3893   iDb = sqlite3FindDbName(db, zDb);
3894   if( iDb==0 || iDb>1 ){
3895     Btree *pBt = db->aDb[iDb].pBt;
3896     if( 0==sqlite3BtreeIsInTrans(pBt) ){
3897       rc = sqlite3BtreeBeginTrans(pBt, 0);
3898       if( rc==SQLITE_OK ){
3899         rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
3900       }
3901     }
3902   }
3903 
3904   sqlite3_mutex_leave(db->mutex);
3905 #endif   /* SQLITE_OMIT_WAL */
3906   return rc;
3907 }
3908 
3909 /*
3910 ** Open a read-transaction on the snapshot idendified by pSnapshot.
3911 */
3912 int sqlite3_snapshot_open(
3913   sqlite3 *db,
3914   const char *zDb,
3915   sqlite3_snapshot *pSnapshot
3916 ){
3917   int rc = SQLITE_ERROR;
3918 #ifndef SQLITE_OMIT_WAL
3919 
3920 #ifdef SQLITE_ENABLE_API_ARMOR
3921   if( !sqlite3SafetyCheckOk(db) ){
3922     return SQLITE_MISUSE_BKPT;
3923   }
3924 #endif
3925   sqlite3_mutex_enter(db->mutex);
3926   if( db->autoCommit==0 ){
3927     int iDb;
3928     iDb = sqlite3FindDbName(db, zDb);
3929     if( iDb==0 || iDb>1 ){
3930       Btree *pBt = db->aDb[iDb].pBt;
3931       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
3932         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
3933         if( rc==SQLITE_OK ){
3934           rc = sqlite3BtreeBeginTrans(pBt, 0);
3935           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
3936         }
3937       }
3938     }
3939   }
3940 
3941   sqlite3_mutex_leave(db->mutex);
3942 #endif   /* SQLITE_OMIT_WAL */
3943   return rc;
3944 }
3945 
3946 /*
3947 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
3948 */
3949 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
3950   sqlite3_free(pSnapshot);
3951 }
3952 #endif /* SQLITE_ENABLE_SNAPSHOT */
3953