xref: /sqlite-3.40.0/src/main.c (revision 02267cc2)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Main file for the SQLite library.  The routines in this file
13 ** implement the programmer interface to the library.  Routines in
14 ** other files are for internal use by SQLite and should not be
15 ** accessed by users of the library.
16 */
17 #include "sqliteInt.h"
18 
19 #ifdef SQLITE_ENABLE_FTS3
20 # include "fts3.h"
21 #endif
22 #ifdef SQLITE_ENABLE_RTREE
23 # include "rtree.h"
24 #endif
25 #ifdef SQLITE_ENABLE_ICU
26 # include "sqliteicu.h"
27 #endif
28 #ifdef SQLITE_ENABLE_JSON1
29 int sqlite3Json1Init(sqlite3*);
30 #endif
31 #ifdef SQLITE_ENABLE_FTS5
32 int sqlite3Fts5Init(sqlite3*);
33 #endif
34 
35 #ifndef SQLITE_AMALGAMATION
36 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
37 ** contains the text of SQLITE_VERSION macro.
38 */
39 const char sqlite3_version[] = SQLITE_VERSION;
40 #endif
41 
42 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
43 ** a pointer to the to the sqlite3_version[] string constant.
44 */
45 const char *sqlite3_libversion(void){ return sqlite3_version; }
46 
47 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
48 ** pointer to a string constant whose value is the same as the
49 ** SQLITE_SOURCE_ID C preprocessor macro.
50 */
51 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
52 
53 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
54 ** returns an integer equal to SQLITE_VERSION_NUMBER.
55 */
56 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
57 
58 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
59 ** zero if and only if SQLite was compiled with mutexing code omitted due to
60 ** the SQLITE_THREADSAFE compile-time option being set to 0.
61 */
62 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
63 
64 /*
65 ** When compiling the test fixture or with debugging enabled (on Win32),
66 ** this variable being set to non-zero will cause OSTRACE macros to emit
67 ** extra diagnostic information.
68 */
69 #ifdef SQLITE_HAVE_OS_TRACE
70 # ifndef SQLITE_DEBUG_OS_TRACE
71 #   define SQLITE_DEBUG_OS_TRACE 0
72 # endif
73   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
74 #endif
75 
76 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
77 /*
78 ** If the following function pointer is not NULL and if
79 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
80 ** I/O active are written using this function.  These messages
81 ** are intended for debugging activity only.
82 */
83 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
84 #endif
85 
86 /*
87 ** If the following global variable points to a string which is the
88 ** name of a directory, then that directory will be used to store
89 ** temporary files.
90 **
91 ** See also the "PRAGMA temp_store_directory" SQL command.
92 */
93 char *sqlite3_temp_directory = 0;
94 
95 /*
96 ** If the following global variable points to a string which is the
97 ** name of a directory, then that directory will be used to store
98 ** all database files specified with a relative pathname.
99 **
100 ** See also the "PRAGMA data_store_directory" SQL command.
101 */
102 char *sqlite3_data_directory = 0;
103 
104 /*
105 ** Initialize SQLite.
106 **
107 ** This routine must be called to initialize the memory allocation,
108 ** VFS, and mutex subsystems prior to doing any serious work with
109 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
110 ** this routine will be called automatically by key routines such as
111 ** sqlite3_open().
112 **
113 ** This routine is a no-op except on its very first call for the process,
114 ** or for the first call after a call to sqlite3_shutdown.
115 **
116 ** The first thread to call this routine runs the initialization to
117 ** completion.  If subsequent threads call this routine before the first
118 ** thread has finished the initialization process, then the subsequent
119 ** threads must block until the first thread finishes with the initialization.
120 **
121 ** The first thread might call this routine recursively.  Recursive
122 ** calls to this routine should not block, of course.  Otherwise the
123 ** initialization process would never complete.
124 **
125 ** Let X be the first thread to enter this routine.  Let Y be some other
126 ** thread.  Then while the initial invocation of this routine by X is
127 ** incomplete, it is required that:
128 **
129 **    *  Calls to this routine from Y must block until the outer-most
130 **       call by X completes.
131 **
132 **    *  Recursive calls to this routine from thread X return immediately
133 **       without blocking.
134 */
135 int sqlite3_initialize(void){
136   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
137   int rc;                                      /* Result code */
138 #ifdef SQLITE_EXTRA_INIT
139   int bRunExtraInit = 0;                       /* Extra initialization needed */
140 #endif
141 
142 #ifdef SQLITE_OMIT_WSD
143   rc = sqlite3_wsd_init(4096, 24);
144   if( rc!=SQLITE_OK ){
145     return rc;
146   }
147 #endif
148 
149   /* If the following assert() fails on some obscure processor/compiler
150   ** combination, the work-around is to set the correct pointer
151   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
152   assert( SQLITE_PTRSIZE==sizeof(char*) );
153 
154   /* If SQLite is already completely initialized, then this call
155   ** to sqlite3_initialize() should be a no-op.  But the initialization
156   ** must be complete.  So isInit must not be set until the very end
157   ** of this routine.
158   */
159   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
160 
161   /* Make sure the mutex subsystem is initialized.  If unable to
162   ** initialize the mutex subsystem, return early with the error.
163   ** If the system is so sick that we are unable to allocate a mutex,
164   ** there is not much SQLite is going to be able to do.
165   **
166   ** The mutex subsystem must take care of serializing its own
167   ** initialization.
168   */
169   rc = sqlite3MutexInit();
170   if( rc ) return rc;
171 
172   /* Initialize the malloc() system and the recursive pInitMutex mutex.
173   ** This operation is protected by the STATIC_MASTER mutex.  Note that
174   ** MutexAlloc() is called for a static mutex prior to initializing the
175   ** malloc subsystem - this implies that the allocation of a static
176   ** mutex must not require support from the malloc subsystem.
177   */
178   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
179   sqlite3_mutex_enter(pMaster);
180   sqlite3GlobalConfig.isMutexInit = 1;
181   if( !sqlite3GlobalConfig.isMallocInit ){
182     rc = sqlite3MallocInit();
183   }
184   if( rc==SQLITE_OK ){
185     sqlite3GlobalConfig.isMallocInit = 1;
186     if( !sqlite3GlobalConfig.pInitMutex ){
187       sqlite3GlobalConfig.pInitMutex =
188            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
189       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
190         rc = SQLITE_NOMEM_BKPT;
191       }
192     }
193   }
194   if( rc==SQLITE_OK ){
195     sqlite3GlobalConfig.nRefInitMutex++;
196   }
197   sqlite3_mutex_leave(pMaster);
198 
199   /* If rc is not SQLITE_OK at this point, then either the malloc
200   ** subsystem could not be initialized or the system failed to allocate
201   ** the pInitMutex mutex. Return an error in either case.  */
202   if( rc!=SQLITE_OK ){
203     return rc;
204   }
205 
206   /* Do the rest of the initialization under the recursive mutex so
207   ** that we will be able to handle recursive calls into
208   ** sqlite3_initialize().  The recursive calls normally come through
209   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
210   ** recursive calls might also be possible.
211   **
212   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
213   ** to the xInit method, so the xInit method need not be threadsafe.
214   **
215   ** The following mutex is what serializes access to the appdef pcache xInit
216   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
217   ** call to sqlite3PcacheInitialize().
218   */
219   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
220   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
221     sqlite3GlobalConfig.inProgress = 1;
222 #ifdef SQLITE_ENABLE_SQLLOG
223     {
224       extern void sqlite3_init_sqllog(void);
225       sqlite3_init_sqllog();
226     }
227 #endif
228     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
229     sqlite3RegisterBuiltinFunctions();
230     if( sqlite3GlobalConfig.isPCacheInit==0 ){
231       rc = sqlite3PcacheInitialize();
232     }
233     if( rc==SQLITE_OK ){
234       sqlite3GlobalConfig.isPCacheInit = 1;
235       rc = sqlite3OsInit();
236     }
237     if( rc==SQLITE_OK ){
238       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
239           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
240       sqlite3GlobalConfig.isInit = 1;
241 #ifdef SQLITE_EXTRA_INIT
242       bRunExtraInit = 1;
243 #endif
244     }
245     sqlite3GlobalConfig.inProgress = 0;
246   }
247   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
248 
249   /* Go back under the static mutex and clean up the recursive
250   ** mutex to prevent a resource leak.
251   */
252   sqlite3_mutex_enter(pMaster);
253   sqlite3GlobalConfig.nRefInitMutex--;
254   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
255     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
256     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
257     sqlite3GlobalConfig.pInitMutex = 0;
258   }
259   sqlite3_mutex_leave(pMaster);
260 
261   /* The following is just a sanity check to make sure SQLite has
262   ** been compiled correctly.  It is important to run this code, but
263   ** we don't want to run it too often and soak up CPU cycles for no
264   ** reason.  So we run it once during initialization.
265   */
266 #ifndef NDEBUG
267 #ifndef SQLITE_OMIT_FLOATING_POINT
268   /* This section of code's only "output" is via assert() statements. */
269   if ( rc==SQLITE_OK ){
270     u64 x = (((u64)1)<<63)-1;
271     double y;
272     assert(sizeof(x)==8);
273     assert(sizeof(x)==sizeof(y));
274     memcpy(&y, &x, 8);
275     assert( sqlite3IsNaN(y) );
276   }
277 #endif
278 #endif
279 
280   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
281   ** compile-time option.
282   */
283 #ifdef SQLITE_EXTRA_INIT
284   if( bRunExtraInit ){
285     int SQLITE_EXTRA_INIT(const char*);
286     rc = SQLITE_EXTRA_INIT(0);
287   }
288 #endif
289 
290   return rc;
291 }
292 
293 /*
294 ** Undo the effects of sqlite3_initialize().  Must not be called while
295 ** there are outstanding database connections or memory allocations or
296 ** while any part of SQLite is otherwise in use in any thread.  This
297 ** routine is not threadsafe.  But it is safe to invoke this routine
298 ** on when SQLite is already shut down.  If SQLite is already shut down
299 ** when this routine is invoked, then this routine is a harmless no-op.
300 */
301 int sqlite3_shutdown(void){
302 #ifdef SQLITE_OMIT_WSD
303   int rc = sqlite3_wsd_init(4096, 24);
304   if( rc!=SQLITE_OK ){
305     return rc;
306   }
307 #endif
308 
309   if( sqlite3GlobalConfig.isInit ){
310 #ifdef SQLITE_EXTRA_SHUTDOWN
311     void SQLITE_EXTRA_SHUTDOWN(void);
312     SQLITE_EXTRA_SHUTDOWN();
313 #endif
314     sqlite3_os_end();
315     sqlite3_reset_auto_extension();
316     sqlite3GlobalConfig.isInit = 0;
317   }
318   if( sqlite3GlobalConfig.isPCacheInit ){
319     sqlite3PcacheShutdown();
320     sqlite3GlobalConfig.isPCacheInit = 0;
321   }
322   if( sqlite3GlobalConfig.isMallocInit ){
323     sqlite3MallocEnd();
324     sqlite3GlobalConfig.isMallocInit = 0;
325 
326 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
327     /* The heap subsystem has now been shutdown and these values are supposed
328     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
329     ** which would rely on that heap subsystem; therefore, make sure these
330     ** values cannot refer to heap memory that was just invalidated when the
331     ** heap subsystem was shutdown.  This is only done if the current call to
332     ** this function resulted in the heap subsystem actually being shutdown.
333     */
334     sqlite3_data_directory = 0;
335     sqlite3_temp_directory = 0;
336 #endif
337   }
338   if( sqlite3GlobalConfig.isMutexInit ){
339     sqlite3MutexEnd();
340     sqlite3GlobalConfig.isMutexInit = 0;
341   }
342 
343   return SQLITE_OK;
344 }
345 
346 /*
347 ** This API allows applications to modify the global configuration of
348 ** the SQLite library at run-time.
349 **
350 ** This routine should only be called when there are no outstanding
351 ** database connections or memory allocations.  This routine is not
352 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
353 ** behavior.
354 */
355 int sqlite3_config(int op, ...){
356   va_list ap;
357   int rc = SQLITE_OK;
358 
359   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
360   ** the SQLite library is in use. */
361   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
362 
363   va_start(ap, op);
364   switch( op ){
365 
366     /* Mutex configuration options are only available in a threadsafe
367     ** compile.
368     */
369 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
370     case SQLITE_CONFIG_SINGLETHREAD: {
371       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
372       ** Single-thread. */
373       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
374       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
375       break;
376     }
377 #endif
378 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
379     case SQLITE_CONFIG_MULTITHREAD: {
380       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
381       ** Multi-thread. */
382       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
383       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
384       break;
385     }
386 #endif
387 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
388     case SQLITE_CONFIG_SERIALIZED: {
389       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
390       ** Serialized. */
391       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
392       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
393       break;
394     }
395 #endif
396 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
397     case SQLITE_CONFIG_MUTEX: {
398       /* Specify an alternative mutex implementation */
399       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
400       break;
401     }
402 #endif
403 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
404     case SQLITE_CONFIG_GETMUTEX: {
405       /* Retrieve the current mutex implementation */
406       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
407       break;
408     }
409 #endif
410 
411     case SQLITE_CONFIG_MALLOC: {
412       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
413       ** single argument which is a pointer to an instance of the
414       ** sqlite3_mem_methods structure. The argument specifies alternative
415       ** low-level memory allocation routines to be used in place of the memory
416       ** allocation routines built into SQLite. */
417       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
418       break;
419     }
420     case SQLITE_CONFIG_GETMALLOC: {
421       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
422       ** single argument which is a pointer to an instance of the
423       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
424       ** filled with the currently defined memory allocation routines. */
425       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
426       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
427       break;
428     }
429     case SQLITE_CONFIG_MEMSTATUS: {
430       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
431       ** single argument of type int, interpreted as a boolean, which enables
432       ** or disables the collection of memory allocation statistics. */
433       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
434       break;
435     }
436     case SQLITE_CONFIG_SCRATCH: {
437       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
438       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
439       ** which the scratch allocations will be drawn, the size of each scratch
440       ** allocation (sz), and the maximum number of scratch allocations (N). */
441       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
442       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
443       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
444       break;
445     }
446     case SQLITE_CONFIG_PAGECACHE: {
447       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
448       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
449       ** the size of each page cache line (sz), and the number of cache lines
450       ** (N). */
451       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
452       sqlite3GlobalConfig.szPage = va_arg(ap, int);
453       sqlite3GlobalConfig.nPage = va_arg(ap, int);
454       break;
455     }
456     case SQLITE_CONFIG_PCACHE_HDRSZ: {
457       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
458       ** a single parameter which is a pointer to an integer and writes into
459       ** that integer the number of extra bytes per page required for each page
460       ** in SQLITE_CONFIG_PAGECACHE. */
461       *va_arg(ap, int*) =
462           sqlite3HeaderSizeBtree() +
463           sqlite3HeaderSizePcache() +
464           sqlite3HeaderSizePcache1();
465       break;
466     }
467 
468     case SQLITE_CONFIG_PCACHE: {
469       /* no-op */
470       break;
471     }
472     case SQLITE_CONFIG_GETPCACHE: {
473       /* now an error */
474       rc = SQLITE_ERROR;
475       break;
476     }
477 
478     case SQLITE_CONFIG_PCACHE2: {
479       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
480       ** single argument which is a pointer to an sqlite3_pcache_methods2
481       ** object. This object specifies the interface to a custom page cache
482       ** implementation. */
483       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
484       break;
485     }
486     case SQLITE_CONFIG_GETPCACHE2: {
487       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
488       ** single argument which is a pointer to an sqlite3_pcache_methods2
489       ** object. SQLite copies of the current page cache implementation into
490       ** that object. */
491       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
492         sqlite3PCacheSetDefault();
493       }
494       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
495       break;
496     }
497 
498 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
499 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
500 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
501 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
502     case SQLITE_CONFIG_HEAP: {
503       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
504       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
505       ** number of bytes in the memory buffer, and the minimum allocation size.
506       */
507       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
508       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
509       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
510 
511       if( sqlite3GlobalConfig.mnReq<1 ){
512         sqlite3GlobalConfig.mnReq = 1;
513       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
514         /* cap min request size at 2^12 */
515         sqlite3GlobalConfig.mnReq = (1<<12);
516       }
517 
518       if( sqlite3GlobalConfig.pHeap==0 ){
519         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
520         ** is NULL, then SQLite reverts to using its default memory allocator
521         ** (the system malloc() implementation), undoing any prior invocation of
522         ** SQLITE_CONFIG_MALLOC.
523         **
524         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
525         ** revert to its default implementation when sqlite3_initialize() is run
526         */
527         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
528       }else{
529         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
530         ** alternative memory allocator is engaged to handle all of SQLites
531         ** memory allocation needs. */
532 #ifdef SQLITE_ENABLE_MEMSYS3
533         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
534 #endif
535 #ifdef SQLITE_ENABLE_MEMSYS5
536         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
537 #endif
538       }
539       break;
540     }
541 #endif
542 
543     case SQLITE_CONFIG_LOOKASIDE: {
544       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
545       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
546       break;
547     }
548 
549     /* Record a pointer to the logger function and its first argument.
550     ** The default is NULL.  Logging is disabled if the function pointer is
551     ** NULL.
552     */
553     case SQLITE_CONFIG_LOG: {
554       /* MSVC is picky about pulling func ptrs from va lists.
555       ** http://support.microsoft.com/kb/47961
556       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
557       */
558       typedef void(*LOGFUNC_t)(void*,int,const char*);
559       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
560       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
561       break;
562     }
563 
564     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
565     ** can be changed at start-time using the
566     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
567     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
568     */
569     case SQLITE_CONFIG_URI: {
570       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
571       ** argument of type int. If non-zero, then URI handling is globally
572       ** enabled. If the parameter is zero, then URI handling is globally
573       ** disabled. */
574       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
575       break;
576     }
577 
578     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
579       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
580       ** option takes a single integer argument which is interpreted as a
581       ** boolean in order to enable or disable the use of covering indices for
582       ** full table scans in the query optimizer. */
583       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
584       break;
585     }
586 
587 #ifdef SQLITE_ENABLE_SQLLOG
588     case SQLITE_CONFIG_SQLLOG: {
589       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
590       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
591       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
592       break;
593     }
594 #endif
595 
596     case SQLITE_CONFIG_MMAP_SIZE: {
597       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
598       ** integer (sqlite3_int64) values that are the default mmap size limit
599       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
600       ** mmap size limit. */
601       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
602       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
603       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
604       ** negative, then that argument is changed to its compile-time default.
605       **
606       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
607       ** silently truncated if necessary so that it does not exceed the
608       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
609       ** compile-time option.
610       */
611       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
612         mxMmap = SQLITE_MAX_MMAP_SIZE;
613       }
614       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
615       if( szMmap>mxMmap) szMmap = mxMmap;
616       sqlite3GlobalConfig.mxMmap = mxMmap;
617       sqlite3GlobalConfig.szMmap = szMmap;
618       break;
619     }
620 
621 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
622     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
623       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
624       ** unsigned integer value that specifies the maximum size of the created
625       ** heap. */
626       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
627       break;
628     }
629 #endif
630 
631     case SQLITE_CONFIG_PMASZ: {
632       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
633       break;
634     }
635 
636     case SQLITE_CONFIG_STMTJRNL_SPILL: {
637       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
638       break;
639     }
640 
641     default: {
642       rc = SQLITE_ERROR;
643       break;
644     }
645   }
646   va_end(ap);
647   return rc;
648 }
649 
650 /*
651 ** Set up the lookaside buffers for a database connection.
652 ** Return SQLITE_OK on success.
653 ** If lookaside is already active, return SQLITE_BUSY.
654 **
655 ** The sz parameter is the number of bytes in each lookaside slot.
656 ** The cnt parameter is the number of slots.  If pStart is NULL the
657 ** space for the lookaside memory is obtained from sqlite3_malloc().
658 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
659 ** the lookaside memory.
660 */
661 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
662 #ifndef SQLITE_OMIT_LOOKASIDE
663   void *pStart;
664   if( db->lookaside.nOut ){
665     return SQLITE_BUSY;
666   }
667   /* Free any existing lookaside buffer for this handle before
668   ** allocating a new one so we don't have to have space for
669   ** both at the same time.
670   */
671   if( db->lookaside.bMalloced ){
672     sqlite3_free(db->lookaside.pStart);
673   }
674   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
675   ** than a pointer to be useful.
676   */
677   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
678   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
679   if( cnt<0 ) cnt = 0;
680   if( sz==0 || cnt==0 ){
681     sz = 0;
682     pStart = 0;
683   }else if( pBuf==0 ){
684     sqlite3BeginBenignMalloc();
685     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
686     sqlite3EndBenignMalloc();
687     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
688   }else{
689     pStart = pBuf;
690   }
691   db->lookaside.pStart = pStart;
692   db->lookaside.pFree = 0;
693   db->lookaside.sz = (u16)sz;
694   if( pStart ){
695     int i;
696     LookasideSlot *p;
697     assert( sz > (int)sizeof(LookasideSlot*) );
698     p = (LookasideSlot*)pStart;
699     for(i=cnt-1; i>=0; i--){
700       p->pNext = db->lookaside.pFree;
701       db->lookaside.pFree = p;
702       p = (LookasideSlot*)&((u8*)p)[sz];
703     }
704     db->lookaside.pEnd = p;
705     db->lookaside.bDisable = 0;
706     db->lookaside.bMalloced = pBuf==0 ?1:0;
707   }else{
708     db->lookaside.pStart = db;
709     db->lookaside.pEnd = db;
710     db->lookaside.bDisable = 1;
711     db->lookaside.bMalloced = 0;
712   }
713 #endif /* SQLITE_OMIT_LOOKASIDE */
714   return SQLITE_OK;
715 }
716 
717 /*
718 ** Return the mutex associated with a database connection.
719 */
720 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
721 #ifdef SQLITE_ENABLE_API_ARMOR
722   if( !sqlite3SafetyCheckOk(db) ){
723     (void)SQLITE_MISUSE_BKPT;
724     return 0;
725   }
726 #endif
727   return db->mutex;
728 }
729 
730 /*
731 ** Free up as much memory as we can from the given database
732 ** connection.
733 */
734 int sqlite3_db_release_memory(sqlite3 *db){
735   int i;
736 
737 #ifdef SQLITE_ENABLE_API_ARMOR
738   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
739 #endif
740   sqlite3_mutex_enter(db->mutex);
741   sqlite3BtreeEnterAll(db);
742   for(i=0; i<db->nDb; i++){
743     Btree *pBt = db->aDb[i].pBt;
744     if( pBt ){
745       Pager *pPager = sqlite3BtreePager(pBt);
746       sqlite3PagerShrink(pPager);
747     }
748   }
749   sqlite3BtreeLeaveAll(db);
750   sqlite3_mutex_leave(db->mutex);
751   return SQLITE_OK;
752 }
753 
754 /*
755 ** Flush any dirty pages in the pager-cache for any attached database
756 ** to disk.
757 */
758 int sqlite3_db_cacheflush(sqlite3 *db){
759   int i;
760   int rc = SQLITE_OK;
761   int bSeenBusy = 0;
762 
763 #ifdef SQLITE_ENABLE_API_ARMOR
764   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
765 #endif
766   sqlite3_mutex_enter(db->mutex);
767   sqlite3BtreeEnterAll(db);
768   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
769     Btree *pBt = db->aDb[i].pBt;
770     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
771       Pager *pPager = sqlite3BtreePager(pBt);
772       rc = sqlite3PagerFlush(pPager);
773       if( rc==SQLITE_BUSY ){
774         bSeenBusy = 1;
775         rc = SQLITE_OK;
776       }
777     }
778   }
779   sqlite3BtreeLeaveAll(db);
780   sqlite3_mutex_leave(db->mutex);
781   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
782 }
783 
784 /*
785 ** Configuration settings for an individual database connection
786 */
787 int sqlite3_db_config(sqlite3 *db, int op, ...){
788   va_list ap;
789   int rc;
790   va_start(ap, op);
791   switch( op ){
792     case SQLITE_DBCONFIG_LOOKASIDE: {
793       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
794       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
795       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
796       rc = setupLookaside(db, pBuf, sz, cnt);
797       break;
798     }
799     default: {
800       static const struct {
801         int op;      /* The opcode */
802         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
803       } aFlagOp[] = {
804         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
805         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
806         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
807       };
808       unsigned int i;
809       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
810       for(i=0; i<ArraySize(aFlagOp); i++){
811         if( aFlagOp[i].op==op ){
812           int onoff = va_arg(ap, int);
813           int *pRes = va_arg(ap, int*);
814           int oldFlags = db->flags;
815           if( onoff>0 ){
816             db->flags |= aFlagOp[i].mask;
817           }else if( onoff==0 ){
818             db->flags &= ~aFlagOp[i].mask;
819           }
820           if( oldFlags!=db->flags ){
821             sqlite3ExpirePreparedStatements(db);
822           }
823           if( pRes ){
824             *pRes = (db->flags & aFlagOp[i].mask)!=0;
825           }
826           rc = SQLITE_OK;
827           break;
828         }
829       }
830       break;
831     }
832   }
833   va_end(ap);
834   return rc;
835 }
836 
837 
838 /*
839 ** Return true if the buffer z[0..n-1] contains all spaces.
840 */
841 static int allSpaces(const char *z, int n){
842   while( n>0 && z[n-1]==' ' ){ n--; }
843   return n==0;
844 }
845 
846 /*
847 ** This is the default collating function named "BINARY" which is always
848 ** available.
849 **
850 ** If the padFlag argument is not NULL then space padding at the end
851 ** of strings is ignored.  This implements the RTRIM collation.
852 */
853 static int binCollFunc(
854   void *padFlag,
855   int nKey1, const void *pKey1,
856   int nKey2, const void *pKey2
857 ){
858   int rc, n;
859   n = nKey1<nKey2 ? nKey1 : nKey2;
860   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
861   ** strings byte by byte using the memcmp() function from the standard C
862   ** library. */
863   rc = memcmp(pKey1, pKey2, n);
864   if( rc==0 ){
865     if( padFlag
866      && allSpaces(((char*)pKey1)+n, nKey1-n)
867      && allSpaces(((char*)pKey2)+n, nKey2-n)
868     ){
869       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
870       ** spaces at the end of either string do not change the result. In other
871       ** words, strings will compare equal to one another as long as they
872       ** differ only in the number of spaces at the end.
873       */
874     }else{
875       rc = nKey1 - nKey2;
876     }
877   }
878   return rc;
879 }
880 
881 /*
882 ** Another built-in collating sequence: NOCASE.
883 **
884 ** This collating sequence is intended to be used for "case independent
885 ** comparison". SQLite's knowledge of upper and lower case equivalents
886 ** extends only to the 26 characters used in the English language.
887 **
888 ** At the moment there is only a UTF-8 implementation.
889 */
890 static int nocaseCollatingFunc(
891   void *NotUsed,
892   int nKey1, const void *pKey1,
893   int nKey2, const void *pKey2
894 ){
895   int r = sqlite3StrNICmp(
896       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
897   UNUSED_PARAMETER(NotUsed);
898   if( 0==r ){
899     r = nKey1-nKey2;
900   }
901   return r;
902 }
903 
904 /*
905 ** Return the ROWID of the most recent insert
906 */
907 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
908 #ifdef SQLITE_ENABLE_API_ARMOR
909   if( !sqlite3SafetyCheckOk(db) ){
910     (void)SQLITE_MISUSE_BKPT;
911     return 0;
912   }
913 #endif
914   return db->lastRowid;
915 }
916 
917 /*
918 ** Return the number of changes in the most recent call to sqlite3_exec().
919 */
920 int sqlite3_changes(sqlite3 *db){
921 #ifdef SQLITE_ENABLE_API_ARMOR
922   if( !sqlite3SafetyCheckOk(db) ){
923     (void)SQLITE_MISUSE_BKPT;
924     return 0;
925   }
926 #endif
927   return db->nChange;
928 }
929 
930 /*
931 ** Return the number of changes since the database handle was opened.
932 */
933 int sqlite3_total_changes(sqlite3 *db){
934 #ifdef SQLITE_ENABLE_API_ARMOR
935   if( !sqlite3SafetyCheckOk(db) ){
936     (void)SQLITE_MISUSE_BKPT;
937     return 0;
938   }
939 #endif
940   return db->nTotalChange;
941 }
942 
943 /*
944 ** Close all open savepoints. This function only manipulates fields of the
945 ** database handle object, it does not close any savepoints that may be open
946 ** at the b-tree/pager level.
947 */
948 void sqlite3CloseSavepoints(sqlite3 *db){
949   while( db->pSavepoint ){
950     Savepoint *pTmp = db->pSavepoint;
951     db->pSavepoint = pTmp->pNext;
952     sqlite3DbFree(db, pTmp);
953   }
954   db->nSavepoint = 0;
955   db->nStatement = 0;
956   db->isTransactionSavepoint = 0;
957 }
958 
959 /*
960 ** Invoke the destructor function associated with FuncDef p, if any. Except,
961 ** if this is not the last copy of the function, do not invoke it. Multiple
962 ** copies of a single function are created when create_function() is called
963 ** with SQLITE_ANY as the encoding.
964 */
965 static void functionDestroy(sqlite3 *db, FuncDef *p){
966   FuncDestructor *pDestructor = p->u.pDestructor;
967   if( pDestructor ){
968     pDestructor->nRef--;
969     if( pDestructor->nRef==0 ){
970       pDestructor->xDestroy(pDestructor->pUserData);
971       sqlite3DbFree(db, pDestructor);
972     }
973   }
974 }
975 
976 /*
977 ** Disconnect all sqlite3_vtab objects that belong to database connection
978 ** db. This is called when db is being closed.
979 */
980 static void disconnectAllVtab(sqlite3 *db){
981 #ifndef SQLITE_OMIT_VIRTUALTABLE
982   int i;
983   HashElem *p;
984   sqlite3BtreeEnterAll(db);
985   for(i=0; i<db->nDb; i++){
986     Schema *pSchema = db->aDb[i].pSchema;
987     if( db->aDb[i].pSchema ){
988       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
989         Table *pTab = (Table *)sqliteHashData(p);
990         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
991       }
992     }
993   }
994   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
995     Module *pMod = (Module *)sqliteHashData(p);
996     if( pMod->pEpoTab ){
997       sqlite3VtabDisconnect(db, pMod->pEpoTab);
998     }
999   }
1000   sqlite3VtabUnlockList(db);
1001   sqlite3BtreeLeaveAll(db);
1002 #else
1003   UNUSED_PARAMETER(db);
1004 #endif
1005 }
1006 
1007 /*
1008 ** Return TRUE if database connection db has unfinalized prepared
1009 ** statements or unfinished sqlite3_backup objects.
1010 */
1011 static int connectionIsBusy(sqlite3 *db){
1012   int j;
1013   assert( sqlite3_mutex_held(db->mutex) );
1014   if( db->pVdbe ) return 1;
1015   for(j=0; j<db->nDb; j++){
1016     Btree *pBt = db->aDb[j].pBt;
1017     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1018   }
1019   return 0;
1020 }
1021 
1022 /*
1023 ** Close an existing SQLite database
1024 */
1025 static int sqlite3Close(sqlite3 *db, int forceZombie){
1026   if( !db ){
1027     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1028     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1029     return SQLITE_OK;
1030   }
1031   if( !sqlite3SafetyCheckSickOrOk(db) ){
1032     return SQLITE_MISUSE_BKPT;
1033   }
1034   sqlite3_mutex_enter(db->mutex);
1035 
1036   /* Force xDisconnect calls on all virtual tables */
1037   disconnectAllVtab(db);
1038 
1039   /* If a transaction is open, the disconnectAllVtab() call above
1040   ** will not have called the xDisconnect() method on any virtual
1041   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1042   ** call will do so. We need to do this before the check for active
1043   ** SQL statements below, as the v-table implementation may be storing
1044   ** some prepared statements internally.
1045   */
1046   sqlite3VtabRollback(db);
1047 
1048   /* Legacy behavior (sqlite3_close() behavior) is to return
1049   ** SQLITE_BUSY if the connection can not be closed immediately.
1050   */
1051   if( !forceZombie && connectionIsBusy(db) ){
1052     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1053        "statements or unfinished backups");
1054     sqlite3_mutex_leave(db->mutex);
1055     return SQLITE_BUSY;
1056   }
1057 
1058 #ifdef SQLITE_ENABLE_SQLLOG
1059   if( sqlite3GlobalConfig.xSqllog ){
1060     /* Closing the handle. Fourth parameter is passed the value 2. */
1061     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1062   }
1063 #endif
1064 
1065   /* Convert the connection into a zombie and then close it.
1066   */
1067   db->magic = SQLITE_MAGIC_ZOMBIE;
1068   sqlite3LeaveMutexAndCloseZombie(db);
1069   return SQLITE_OK;
1070 }
1071 
1072 /*
1073 ** Two variations on the public interface for closing a database
1074 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1075 ** leaves the connection option if there are unfinalized prepared
1076 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1077 ** version forces the connection to become a zombie if there are
1078 ** unclosed resources, and arranges for deallocation when the last
1079 ** prepare statement or sqlite3_backup closes.
1080 */
1081 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1082 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1083 
1084 
1085 /*
1086 ** Close the mutex on database connection db.
1087 **
1088 ** Furthermore, if database connection db is a zombie (meaning that there
1089 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1090 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1091 ** finished, then free all resources.
1092 */
1093 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1094   HashElem *i;                    /* Hash table iterator */
1095   int j;
1096 
1097   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1098   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1099   ** then just leave the mutex and return.
1100   */
1101   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1102     sqlite3_mutex_leave(db->mutex);
1103     return;
1104   }
1105 
1106   /* If we reach this point, it means that the database connection has
1107   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1108   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1109   ** go ahead and free all resources.
1110   */
1111 
1112   /* If a transaction is open, roll it back. This also ensures that if
1113   ** any database schemas have been modified by an uncommitted transaction
1114   ** they are reset. And that the required b-tree mutex is held to make
1115   ** the pager rollback and schema reset an atomic operation. */
1116   sqlite3RollbackAll(db, SQLITE_OK);
1117 
1118   /* Free any outstanding Savepoint structures. */
1119   sqlite3CloseSavepoints(db);
1120 
1121   /* Close all database connections */
1122   for(j=0; j<db->nDb; j++){
1123     struct Db *pDb = &db->aDb[j];
1124     if( pDb->pBt ){
1125       sqlite3BtreeClose(pDb->pBt);
1126       pDb->pBt = 0;
1127       if( j!=1 ){
1128         pDb->pSchema = 0;
1129       }
1130     }
1131   }
1132   /* Clear the TEMP schema separately and last */
1133   if( db->aDb[1].pSchema ){
1134     sqlite3SchemaClear(db->aDb[1].pSchema);
1135   }
1136   sqlite3VtabUnlockList(db);
1137 
1138   /* Free up the array of auxiliary databases */
1139   sqlite3CollapseDatabaseArray(db);
1140   assert( db->nDb<=2 );
1141   assert( db->aDb==db->aDbStatic );
1142 
1143   /* Tell the code in notify.c that the connection no longer holds any
1144   ** locks and does not require any further unlock-notify callbacks.
1145   */
1146   sqlite3ConnectionClosed(db);
1147 
1148   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1149     FuncDef *pNext, *p;
1150     p = sqliteHashData(i);
1151     do{
1152       functionDestroy(db, p);
1153       pNext = p->pNext;
1154       sqlite3DbFree(db, p);
1155       p = pNext;
1156     }while( p );
1157   }
1158   sqlite3HashClear(&db->aFunc);
1159   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1160     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1161     /* Invoke any destructors registered for collation sequence user data. */
1162     for(j=0; j<3; j++){
1163       if( pColl[j].xDel ){
1164         pColl[j].xDel(pColl[j].pUser);
1165       }
1166     }
1167     sqlite3DbFree(db, pColl);
1168   }
1169   sqlite3HashClear(&db->aCollSeq);
1170 #ifndef SQLITE_OMIT_VIRTUALTABLE
1171   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1172     Module *pMod = (Module *)sqliteHashData(i);
1173     if( pMod->xDestroy ){
1174       pMod->xDestroy(pMod->pAux);
1175     }
1176     sqlite3VtabEponymousTableClear(db, pMod);
1177     sqlite3DbFree(db, pMod);
1178   }
1179   sqlite3HashClear(&db->aModule);
1180 #endif
1181 
1182   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1183   sqlite3ValueFree(db->pErr);
1184   sqlite3CloseExtensions(db);
1185 #if SQLITE_USER_AUTHENTICATION
1186   sqlite3_free(db->auth.zAuthUser);
1187   sqlite3_free(db->auth.zAuthPW);
1188 #endif
1189 
1190   db->magic = SQLITE_MAGIC_ERROR;
1191 
1192   /* The temp-database schema is allocated differently from the other schema
1193   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1194   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1195   ** the same sqliteMalloc() as the one that allocates the database
1196   ** structure?
1197   */
1198   sqlite3DbFree(db, db->aDb[1].pSchema);
1199   sqlite3_mutex_leave(db->mutex);
1200   db->magic = SQLITE_MAGIC_CLOSED;
1201   sqlite3_mutex_free(db->mutex);
1202   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1203   if( db->lookaside.bMalloced ){
1204     sqlite3_free(db->lookaside.pStart);
1205   }
1206   sqlite3_free(db);
1207 }
1208 
1209 /*
1210 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1211 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1212 ** breaker") and made to return tripCode if there are any further
1213 ** attempts to use that cursor.  Read cursors remain open and valid
1214 ** but are "saved" in case the table pages are moved around.
1215 */
1216 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1217   int i;
1218   int inTrans = 0;
1219   int schemaChange;
1220   assert( sqlite3_mutex_held(db->mutex) );
1221   sqlite3BeginBenignMalloc();
1222 
1223   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1224   ** This is important in case the transaction being rolled back has
1225   ** modified the database schema. If the b-tree mutexes are not taken
1226   ** here, then another shared-cache connection might sneak in between
1227   ** the database rollback and schema reset, which can cause false
1228   ** corruption reports in some cases.  */
1229   sqlite3BtreeEnterAll(db);
1230   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1231 
1232   for(i=0; i<db->nDb; i++){
1233     Btree *p = db->aDb[i].pBt;
1234     if( p ){
1235       if( sqlite3BtreeIsInTrans(p) ){
1236         inTrans = 1;
1237       }
1238       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1239     }
1240   }
1241   sqlite3VtabRollback(db);
1242   sqlite3EndBenignMalloc();
1243 
1244   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1245     sqlite3ExpirePreparedStatements(db);
1246     sqlite3ResetAllSchemasOfConnection(db);
1247   }
1248   sqlite3BtreeLeaveAll(db);
1249 
1250   /* Any deferred constraint violations have now been resolved. */
1251   db->nDeferredCons = 0;
1252   db->nDeferredImmCons = 0;
1253   db->flags &= ~SQLITE_DeferFKs;
1254 
1255   /* If one has been configured, invoke the rollback-hook callback */
1256   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1257     db->xRollbackCallback(db->pRollbackArg);
1258   }
1259 }
1260 
1261 /*
1262 ** Return a static string containing the name corresponding to the error code
1263 ** specified in the argument.
1264 */
1265 #if defined(SQLITE_NEED_ERR_NAME)
1266 const char *sqlite3ErrName(int rc){
1267   const char *zName = 0;
1268   int i, origRc = rc;
1269   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1270     switch( rc ){
1271       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1272       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1273       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1274       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1275       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1276       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1277       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1278       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1279       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1280       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1281       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1282       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1283       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1284       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1285       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1286       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1287       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1288       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1289       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1290       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1291       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1292       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1293       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1294       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1295       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1296       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1297       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1298       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1299       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1300       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1301       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1302       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1303                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1304       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1305       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1306       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1307       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1308       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1309       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1310       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1311       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1312       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1313       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1314       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1315       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1316       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1317       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1318       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1319       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1320       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1321       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1322       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1323       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1324       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1325       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1326       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1327       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1328       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1329       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1330       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1331       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1332       case SQLITE_CONSTRAINT_FOREIGNKEY:
1333                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1334       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1335       case SQLITE_CONSTRAINT_PRIMARYKEY:
1336                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1337       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1338       case SQLITE_CONSTRAINT_COMMITHOOK:
1339                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1340       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1341       case SQLITE_CONSTRAINT_FUNCTION:
1342                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1343       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1344       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1345       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1346       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1347       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1348       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1349       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1350       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1351       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1352       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1353       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1354       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1355                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1356       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1357       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1358       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1359     }
1360   }
1361   if( zName==0 ){
1362     static char zBuf[50];
1363     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1364     zName = zBuf;
1365   }
1366   return zName;
1367 }
1368 #endif
1369 
1370 /*
1371 ** Return a static string that describes the kind of error specified in the
1372 ** argument.
1373 */
1374 const char *sqlite3ErrStr(int rc){
1375   static const char* const aMsg[] = {
1376     /* SQLITE_OK          */ "not an error",
1377     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1378     /* SQLITE_INTERNAL    */ 0,
1379     /* SQLITE_PERM        */ "access permission denied",
1380     /* SQLITE_ABORT       */ "callback requested query abort",
1381     /* SQLITE_BUSY        */ "database is locked",
1382     /* SQLITE_LOCKED      */ "database table is locked",
1383     /* SQLITE_NOMEM       */ "out of memory",
1384     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1385     /* SQLITE_INTERRUPT   */ "interrupted",
1386     /* SQLITE_IOERR       */ "disk I/O error",
1387     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1388     /* SQLITE_NOTFOUND    */ "unknown operation",
1389     /* SQLITE_FULL        */ "database or disk is full",
1390     /* SQLITE_CANTOPEN    */ "unable to open database file",
1391     /* SQLITE_PROTOCOL    */ "locking protocol",
1392     /* SQLITE_EMPTY       */ "table contains no data",
1393     /* SQLITE_SCHEMA      */ "database schema has changed",
1394     /* SQLITE_TOOBIG      */ "string or blob too big",
1395     /* SQLITE_CONSTRAINT  */ "constraint failed",
1396     /* SQLITE_MISMATCH    */ "datatype mismatch",
1397     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1398     /* SQLITE_NOLFS       */ "large file support is disabled",
1399     /* SQLITE_AUTH        */ "authorization denied",
1400     /* SQLITE_FORMAT      */ "auxiliary database format error",
1401     /* SQLITE_RANGE       */ "bind or column index out of range",
1402     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1403   };
1404   const char *zErr = "unknown error";
1405   switch( rc ){
1406     case SQLITE_ABORT_ROLLBACK: {
1407       zErr = "abort due to ROLLBACK";
1408       break;
1409     }
1410     default: {
1411       rc &= 0xff;
1412       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1413         zErr = aMsg[rc];
1414       }
1415       break;
1416     }
1417   }
1418   return zErr;
1419 }
1420 
1421 /*
1422 ** This routine implements a busy callback that sleeps and tries
1423 ** again until a timeout value is reached.  The timeout value is
1424 ** an integer number of milliseconds passed in as the first
1425 ** argument.
1426 */
1427 static int sqliteDefaultBusyCallback(
1428  void *ptr,               /* Database connection */
1429  int count                /* Number of times table has been busy */
1430 ){
1431 #if SQLITE_OS_WIN || HAVE_USLEEP
1432   static const u8 delays[] =
1433      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1434   static const u8 totals[] =
1435      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1436 # define NDELAY ArraySize(delays)
1437   sqlite3 *db = (sqlite3 *)ptr;
1438   int timeout = db->busyTimeout;
1439   int delay, prior;
1440 
1441   assert( count>=0 );
1442   if( count < NDELAY ){
1443     delay = delays[count];
1444     prior = totals[count];
1445   }else{
1446     delay = delays[NDELAY-1];
1447     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1448   }
1449   if( prior + delay > timeout ){
1450     delay = timeout - prior;
1451     if( delay<=0 ) return 0;
1452   }
1453   sqlite3OsSleep(db->pVfs, delay*1000);
1454   return 1;
1455 #else
1456   sqlite3 *db = (sqlite3 *)ptr;
1457   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1458   if( (count+1)*1000 > timeout ){
1459     return 0;
1460   }
1461   sqlite3OsSleep(db->pVfs, 1000000);
1462   return 1;
1463 #endif
1464 }
1465 
1466 /*
1467 ** Invoke the given busy handler.
1468 **
1469 ** This routine is called when an operation failed with a lock.
1470 ** If this routine returns non-zero, the lock is retried.  If it
1471 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1472 */
1473 int sqlite3InvokeBusyHandler(BusyHandler *p){
1474   int rc;
1475   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1476   rc = p->xFunc(p->pArg, p->nBusy);
1477   if( rc==0 ){
1478     p->nBusy = -1;
1479   }else{
1480     p->nBusy++;
1481   }
1482   return rc;
1483 }
1484 
1485 /*
1486 ** This routine sets the busy callback for an Sqlite database to the
1487 ** given callback function with the given argument.
1488 */
1489 int sqlite3_busy_handler(
1490   sqlite3 *db,
1491   int (*xBusy)(void*,int),
1492   void *pArg
1493 ){
1494 #ifdef SQLITE_ENABLE_API_ARMOR
1495   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1496 #endif
1497   sqlite3_mutex_enter(db->mutex);
1498   db->busyHandler.xFunc = xBusy;
1499   db->busyHandler.pArg = pArg;
1500   db->busyHandler.nBusy = 0;
1501   db->busyTimeout = 0;
1502   sqlite3_mutex_leave(db->mutex);
1503   return SQLITE_OK;
1504 }
1505 
1506 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1507 /*
1508 ** This routine sets the progress callback for an Sqlite database to the
1509 ** given callback function with the given argument. The progress callback will
1510 ** be invoked every nOps opcodes.
1511 */
1512 void sqlite3_progress_handler(
1513   sqlite3 *db,
1514   int nOps,
1515   int (*xProgress)(void*),
1516   void *pArg
1517 ){
1518 #ifdef SQLITE_ENABLE_API_ARMOR
1519   if( !sqlite3SafetyCheckOk(db) ){
1520     (void)SQLITE_MISUSE_BKPT;
1521     return;
1522   }
1523 #endif
1524   sqlite3_mutex_enter(db->mutex);
1525   if( nOps>0 ){
1526     db->xProgress = xProgress;
1527     db->nProgressOps = (unsigned)nOps;
1528     db->pProgressArg = pArg;
1529   }else{
1530     db->xProgress = 0;
1531     db->nProgressOps = 0;
1532     db->pProgressArg = 0;
1533   }
1534   sqlite3_mutex_leave(db->mutex);
1535 }
1536 #endif
1537 
1538 
1539 /*
1540 ** This routine installs a default busy handler that waits for the
1541 ** specified number of milliseconds before returning 0.
1542 */
1543 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1544 #ifdef SQLITE_ENABLE_API_ARMOR
1545   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1546 #endif
1547   if( ms>0 ){
1548     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1549     db->busyTimeout = ms;
1550   }else{
1551     sqlite3_busy_handler(db, 0, 0);
1552   }
1553   return SQLITE_OK;
1554 }
1555 
1556 /*
1557 ** Cause any pending operation to stop at its earliest opportunity.
1558 */
1559 void sqlite3_interrupt(sqlite3 *db){
1560 #ifdef SQLITE_ENABLE_API_ARMOR
1561   if( !sqlite3SafetyCheckOk(db) ){
1562     (void)SQLITE_MISUSE_BKPT;
1563     return;
1564   }
1565 #endif
1566   db->u1.isInterrupted = 1;
1567 }
1568 
1569 
1570 /*
1571 ** This function is exactly the same as sqlite3_create_function(), except
1572 ** that it is designed to be called by internal code. The difference is
1573 ** that if a malloc() fails in sqlite3_create_function(), an error code
1574 ** is returned and the mallocFailed flag cleared.
1575 */
1576 int sqlite3CreateFunc(
1577   sqlite3 *db,
1578   const char *zFunctionName,
1579   int nArg,
1580   int enc,
1581   void *pUserData,
1582   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1583   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1584   void (*xFinal)(sqlite3_context*),
1585   FuncDestructor *pDestructor
1586 ){
1587   FuncDef *p;
1588   int nName;
1589   int extraFlags;
1590 
1591   assert( sqlite3_mutex_held(db->mutex) );
1592   if( zFunctionName==0 ||
1593       (xSFunc && (xFinal || xStep)) ||
1594       (!xSFunc && (xFinal && !xStep)) ||
1595       (!xSFunc && (!xFinal && xStep)) ||
1596       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1597       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1598     return SQLITE_MISUSE_BKPT;
1599   }
1600 
1601   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1602   extraFlags = enc &  SQLITE_DETERMINISTIC;
1603   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1604 
1605 #ifndef SQLITE_OMIT_UTF16
1606   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1607   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1608   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1609   **
1610   ** If SQLITE_ANY is specified, add three versions of the function
1611   ** to the hash table.
1612   */
1613   if( enc==SQLITE_UTF16 ){
1614     enc = SQLITE_UTF16NATIVE;
1615   }else if( enc==SQLITE_ANY ){
1616     int rc;
1617     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1618          pUserData, xSFunc, xStep, xFinal, pDestructor);
1619     if( rc==SQLITE_OK ){
1620       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1621           pUserData, xSFunc, xStep, xFinal, pDestructor);
1622     }
1623     if( rc!=SQLITE_OK ){
1624       return rc;
1625     }
1626     enc = SQLITE_UTF16BE;
1627   }
1628 #else
1629   enc = SQLITE_UTF8;
1630 #endif
1631 
1632   /* Check if an existing function is being overridden or deleted. If so,
1633   ** and there are active VMs, then return SQLITE_BUSY. If a function
1634   ** is being overridden/deleted but there are no active VMs, allow the
1635   ** operation to continue but invalidate all precompiled statements.
1636   */
1637   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1638   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1639     if( db->nVdbeActive ){
1640       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1641         "unable to delete/modify user-function due to active statements");
1642       assert( !db->mallocFailed );
1643       return SQLITE_BUSY;
1644     }else{
1645       sqlite3ExpirePreparedStatements(db);
1646     }
1647   }
1648 
1649   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1650   assert(p || db->mallocFailed);
1651   if( !p ){
1652     return SQLITE_NOMEM_BKPT;
1653   }
1654 
1655   /* If an older version of the function with a configured destructor is
1656   ** being replaced invoke the destructor function here. */
1657   functionDestroy(db, p);
1658 
1659   if( pDestructor ){
1660     pDestructor->nRef++;
1661   }
1662   p->u.pDestructor = pDestructor;
1663   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1664   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1665   p->xSFunc = xSFunc ? xSFunc : xStep;
1666   p->xFinalize = xFinal;
1667   p->pUserData = pUserData;
1668   p->nArg = (u16)nArg;
1669   return SQLITE_OK;
1670 }
1671 
1672 /*
1673 ** Create new user functions.
1674 */
1675 int sqlite3_create_function(
1676   sqlite3 *db,
1677   const char *zFunc,
1678   int nArg,
1679   int enc,
1680   void *p,
1681   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1682   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1683   void (*xFinal)(sqlite3_context*)
1684 ){
1685   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1686                                     xFinal, 0);
1687 }
1688 
1689 int sqlite3_create_function_v2(
1690   sqlite3 *db,
1691   const char *zFunc,
1692   int nArg,
1693   int enc,
1694   void *p,
1695   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1696   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1697   void (*xFinal)(sqlite3_context*),
1698   void (*xDestroy)(void *)
1699 ){
1700   int rc = SQLITE_ERROR;
1701   FuncDestructor *pArg = 0;
1702 
1703 #ifdef SQLITE_ENABLE_API_ARMOR
1704   if( !sqlite3SafetyCheckOk(db) ){
1705     return SQLITE_MISUSE_BKPT;
1706   }
1707 #endif
1708   sqlite3_mutex_enter(db->mutex);
1709   if( xDestroy ){
1710     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1711     if( !pArg ){
1712       xDestroy(p);
1713       goto out;
1714     }
1715     pArg->xDestroy = xDestroy;
1716     pArg->pUserData = p;
1717   }
1718   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1719   if( pArg && pArg->nRef==0 ){
1720     assert( rc!=SQLITE_OK );
1721     xDestroy(p);
1722     sqlite3DbFree(db, pArg);
1723   }
1724 
1725  out:
1726   rc = sqlite3ApiExit(db, rc);
1727   sqlite3_mutex_leave(db->mutex);
1728   return rc;
1729 }
1730 
1731 #ifndef SQLITE_OMIT_UTF16
1732 int sqlite3_create_function16(
1733   sqlite3 *db,
1734   const void *zFunctionName,
1735   int nArg,
1736   int eTextRep,
1737   void *p,
1738   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1739   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1740   void (*xFinal)(sqlite3_context*)
1741 ){
1742   int rc;
1743   char *zFunc8;
1744 
1745 #ifdef SQLITE_ENABLE_API_ARMOR
1746   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1747 #endif
1748   sqlite3_mutex_enter(db->mutex);
1749   assert( !db->mallocFailed );
1750   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1751   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1752   sqlite3DbFree(db, zFunc8);
1753   rc = sqlite3ApiExit(db, rc);
1754   sqlite3_mutex_leave(db->mutex);
1755   return rc;
1756 }
1757 #endif
1758 
1759 
1760 /*
1761 ** Declare that a function has been overloaded by a virtual table.
1762 **
1763 ** If the function already exists as a regular global function, then
1764 ** this routine is a no-op.  If the function does not exist, then create
1765 ** a new one that always throws a run-time error.
1766 **
1767 ** When virtual tables intend to provide an overloaded function, they
1768 ** should call this routine to make sure the global function exists.
1769 ** A global function must exist in order for name resolution to work
1770 ** properly.
1771 */
1772 int sqlite3_overload_function(
1773   sqlite3 *db,
1774   const char *zName,
1775   int nArg
1776 ){
1777   int rc = SQLITE_OK;
1778 
1779 #ifdef SQLITE_ENABLE_API_ARMOR
1780   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1781     return SQLITE_MISUSE_BKPT;
1782   }
1783 #endif
1784   sqlite3_mutex_enter(db->mutex);
1785   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1786     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1787                            0, sqlite3InvalidFunction, 0, 0, 0);
1788   }
1789   rc = sqlite3ApiExit(db, rc);
1790   sqlite3_mutex_leave(db->mutex);
1791   return rc;
1792 }
1793 
1794 #ifndef SQLITE_OMIT_TRACE
1795 /*
1796 ** Register a trace function.  The pArg from the previously registered trace
1797 ** is returned.
1798 **
1799 ** A NULL trace function means that no tracing is executes.  A non-NULL
1800 ** trace is a pointer to a function that is invoked at the start of each
1801 ** SQL statement.
1802 */
1803 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1804   void *pOld;
1805 
1806 #ifdef SQLITE_ENABLE_API_ARMOR
1807   if( !sqlite3SafetyCheckOk(db) ){
1808     (void)SQLITE_MISUSE_BKPT;
1809     return 0;
1810   }
1811 #endif
1812   sqlite3_mutex_enter(db->mutex);
1813   pOld = db->pTraceArg;
1814   db->xTrace = xTrace;
1815   db->pTraceArg = pArg;
1816   sqlite3_mutex_leave(db->mutex);
1817   return pOld;
1818 }
1819 /*
1820 ** Register a profile function.  The pArg from the previously registered
1821 ** profile function is returned.
1822 **
1823 ** A NULL profile function means that no profiling is executes.  A non-NULL
1824 ** profile is a pointer to a function that is invoked at the conclusion of
1825 ** each SQL statement that is run.
1826 */
1827 void *sqlite3_profile(
1828   sqlite3 *db,
1829   void (*xProfile)(void*,const char*,sqlite_uint64),
1830   void *pArg
1831 ){
1832   void *pOld;
1833 
1834 #ifdef SQLITE_ENABLE_API_ARMOR
1835   if( !sqlite3SafetyCheckOk(db) ){
1836     (void)SQLITE_MISUSE_BKPT;
1837     return 0;
1838   }
1839 #endif
1840   sqlite3_mutex_enter(db->mutex);
1841   pOld = db->pProfileArg;
1842   db->xProfile = xProfile;
1843   db->pProfileArg = pArg;
1844   sqlite3_mutex_leave(db->mutex);
1845   return pOld;
1846 }
1847 #endif /* SQLITE_OMIT_TRACE */
1848 
1849 /*
1850 ** Register a function to be invoked when a transaction commits.
1851 ** If the invoked function returns non-zero, then the commit becomes a
1852 ** rollback.
1853 */
1854 void *sqlite3_commit_hook(
1855   sqlite3 *db,              /* Attach the hook to this database */
1856   int (*xCallback)(void*),  /* Function to invoke on each commit */
1857   void *pArg                /* Argument to the function */
1858 ){
1859   void *pOld;
1860 
1861 #ifdef SQLITE_ENABLE_API_ARMOR
1862   if( !sqlite3SafetyCheckOk(db) ){
1863     (void)SQLITE_MISUSE_BKPT;
1864     return 0;
1865   }
1866 #endif
1867   sqlite3_mutex_enter(db->mutex);
1868   pOld = db->pCommitArg;
1869   db->xCommitCallback = xCallback;
1870   db->pCommitArg = pArg;
1871   sqlite3_mutex_leave(db->mutex);
1872   return pOld;
1873 }
1874 
1875 /*
1876 ** Register a callback to be invoked each time a row is updated,
1877 ** inserted or deleted using this database connection.
1878 */
1879 void *sqlite3_update_hook(
1880   sqlite3 *db,              /* Attach the hook to this database */
1881   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1882   void *pArg                /* Argument to the function */
1883 ){
1884   void *pRet;
1885 
1886 #ifdef SQLITE_ENABLE_API_ARMOR
1887   if( !sqlite3SafetyCheckOk(db) ){
1888     (void)SQLITE_MISUSE_BKPT;
1889     return 0;
1890   }
1891 #endif
1892   sqlite3_mutex_enter(db->mutex);
1893   pRet = db->pUpdateArg;
1894   db->xUpdateCallback = xCallback;
1895   db->pUpdateArg = pArg;
1896   sqlite3_mutex_leave(db->mutex);
1897   return pRet;
1898 }
1899 
1900 /*
1901 ** Register a callback to be invoked each time a transaction is rolled
1902 ** back by this database connection.
1903 */
1904 void *sqlite3_rollback_hook(
1905   sqlite3 *db,              /* Attach the hook to this database */
1906   void (*xCallback)(void*), /* Callback function */
1907   void *pArg                /* Argument to the function */
1908 ){
1909   void *pRet;
1910 
1911 #ifdef SQLITE_ENABLE_API_ARMOR
1912   if( !sqlite3SafetyCheckOk(db) ){
1913     (void)SQLITE_MISUSE_BKPT;
1914     return 0;
1915   }
1916 #endif
1917   sqlite3_mutex_enter(db->mutex);
1918   pRet = db->pRollbackArg;
1919   db->xRollbackCallback = xCallback;
1920   db->pRollbackArg = pArg;
1921   sqlite3_mutex_leave(db->mutex);
1922   return pRet;
1923 }
1924 
1925 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1926 /*
1927 ** Register a callback to be invoked each time a row is updated,
1928 ** inserted or deleted using this database connection.
1929 */
1930 void *sqlite3_preupdate_hook(
1931   sqlite3 *db,              /* Attach the hook to this database */
1932   void(*xCallback)(         /* Callback function */
1933     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
1934   void *pArg                /* First callback argument */
1935 ){
1936   void *pRet;
1937   sqlite3_mutex_enter(db->mutex);
1938   pRet = db->pPreUpdateArg;
1939   db->xPreUpdateCallback = xCallback;
1940   db->pPreUpdateArg = pArg;
1941   sqlite3_mutex_leave(db->mutex);
1942   return pRet;
1943 }
1944 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
1945 
1946 #ifndef SQLITE_OMIT_WAL
1947 /*
1948 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1949 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1950 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1951 ** wal_autocheckpoint()).
1952 */
1953 int sqlite3WalDefaultHook(
1954   void *pClientData,     /* Argument */
1955   sqlite3 *db,           /* Connection */
1956   const char *zDb,       /* Database */
1957   int nFrame             /* Size of WAL */
1958 ){
1959   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1960     sqlite3BeginBenignMalloc();
1961     sqlite3_wal_checkpoint(db, zDb);
1962     sqlite3EndBenignMalloc();
1963   }
1964   return SQLITE_OK;
1965 }
1966 #endif /* SQLITE_OMIT_WAL */
1967 
1968 /*
1969 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1970 ** a database after committing a transaction if there are nFrame or
1971 ** more frames in the log file. Passing zero or a negative value as the
1972 ** nFrame parameter disables automatic checkpoints entirely.
1973 **
1974 ** The callback registered by this function replaces any existing callback
1975 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1976 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1977 ** configured by this function.
1978 */
1979 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1980 #ifdef SQLITE_OMIT_WAL
1981   UNUSED_PARAMETER(db);
1982   UNUSED_PARAMETER(nFrame);
1983 #else
1984 #ifdef SQLITE_ENABLE_API_ARMOR
1985   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1986 #endif
1987   if( nFrame>0 ){
1988     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1989   }else{
1990     sqlite3_wal_hook(db, 0, 0);
1991   }
1992 #endif
1993   return SQLITE_OK;
1994 }
1995 
1996 /*
1997 ** Register a callback to be invoked each time a transaction is written
1998 ** into the write-ahead-log by this database connection.
1999 */
2000 void *sqlite3_wal_hook(
2001   sqlite3 *db,                    /* Attach the hook to this db handle */
2002   int(*xCallback)(void *, sqlite3*, const char*, int),
2003   void *pArg                      /* First argument passed to xCallback() */
2004 ){
2005 #ifndef SQLITE_OMIT_WAL
2006   void *pRet;
2007 #ifdef SQLITE_ENABLE_API_ARMOR
2008   if( !sqlite3SafetyCheckOk(db) ){
2009     (void)SQLITE_MISUSE_BKPT;
2010     return 0;
2011   }
2012 #endif
2013   sqlite3_mutex_enter(db->mutex);
2014   pRet = db->pWalArg;
2015   db->xWalCallback = xCallback;
2016   db->pWalArg = pArg;
2017   sqlite3_mutex_leave(db->mutex);
2018   return pRet;
2019 #else
2020   return 0;
2021 #endif
2022 }
2023 
2024 /*
2025 ** Checkpoint database zDb.
2026 */
2027 int sqlite3_wal_checkpoint_v2(
2028   sqlite3 *db,                    /* Database handle */
2029   const char *zDb,                /* Name of attached database (or NULL) */
2030   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2031   int *pnLog,                     /* OUT: Size of WAL log in frames */
2032   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2033 ){
2034 #ifdef SQLITE_OMIT_WAL
2035   return SQLITE_OK;
2036 #else
2037   int rc;                         /* Return code */
2038   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2039 
2040 #ifdef SQLITE_ENABLE_API_ARMOR
2041   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2042 #endif
2043 
2044   /* Initialize the output variables to -1 in case an error occurs. */
2045   if( pnLog ) *pnLog = -1;
2046   if( pnCkpt ) *pnCkpt = -1;
2047 
2048   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2049   assert( SQLITE_CHECKPOINT_FULL==1 );
2050   assert( SQLITE_CHECKPOINT_RESTART==2 );
2051   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2052   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2053     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2054     ** mode: */
2055     return SQLITE_MISUSE;
2056   }
2057 
2058   sqlite3_mutex_enter(db->mutex);
2059   if( zDb && zDb[0] ){
2060     iDb = sqlite3FindDbName(db, zDb);
2061   }
2062   if( iDb<0 ){
2063     rc = SQLITE_ERROR;
2064     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2065   }else{
2066     db->busyHandler.nBusy = 0;
2067     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2068     sqlite3Error(db, rc);
2069   }
2070   rc = sqlite3ApiExit(db, rc);
2071   sqlite3_mutex_leave(db->mutex);
2072   return rc;
2073 #endif
2074 }
2075 
2076 
2077 /*
2078 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2079 ** to contains a zero-length string, all attached databases are
2080 ** checkpointed.
2081 */
2082 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2083   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2084   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2085   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2086 }
2087 
2088 #ifndef SQLITE_OMIT_WAL
2089 /*
2090 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2091 ** not currently open in WAL mode.
2092 **
2093 ** If a transaction is open on the database being checkpointed, this
2094 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2095 ** an error occurs while running the checkpoint, an SQLite error code is
2096 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2097 **
2098 ** The mutex on database handle db should be held by the caller. The mutex
2099 ** associated with the specific b-tree being checkpointed is taken by
2100 ** this function while the checkpoint is running.
2101 **
2102 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2103 ** checkpointed. If an error is encountered it is returned immediately -
2104 ** no attempt is made to checkpoint any remaining databases.
2105 **
2106 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2107 */
2108 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2109   int rc = SQLITE_OK;             /* Return code */
2110   int i;                          /* Used to iterate through attached dbs */
2111   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2112 
2113   assert( sqlite3_mutex_held(db->mutex) );
2114   assert( !pnLog || *pnLog==-1 );
2115   assert( !pnCkpt || *pnCkpt==-1 );
2116 
2117   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2118     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2119       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2120       pnLog = 0;
2121       pnCkpt = 0;
2122       if( rc==SQLITE_BUSY ){
2123         bBusy = 1;
2124         rc = SQLITE_OK;
2125       }
2126     }
2127   }
2128 
2129   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2130 }
2131 #endif /* SQLITE_OMIT_WAL */
2132 
2133 /*
2134 ** This function returns true if main-memory should be used instead of
2135 ** a temporary file for transient pager files and statement journals.
2136 ** The value returned depends on the value of db->temp_store (runtime
2137 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2138 ** following table describes the relationship between these two values
2139 ** and this functions return value.
2140 **
2141 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2142 **   -----------------     --------------     ------------------------------
2143 **   0                     any                file      (return 0)
2144 **   1                     1                  file      (return 0)
2145 **   1                     2                  memory    (return 1)
2146 **   1                     0                  file      (return 0)
2147 **   2                     1                  file      (return 0)
2148 **   2                     2                  memory    (return 1)
2149 **   2                     0                  memory    (return 1)
2150 **   3                     any                memory    (return 1)
2151 */
2152 int sqlite3TempInMemory(const sqlite3 *db){
2153 #if SQLITE_TEMP_STORE==1
2154   return ( db->temp_store==2 );
2155 #endif
2156 #if SQLITE_TEMP_STORE==2
2157   return ( db->temp_store!=1 );
2158 #endif
2159 #if SQLITE_TEMP_STORE==3
2160   UNUSED_PARAMETER(db);
2161   return 1;
2162 #endif
2163 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2164   UNUSED_PARAMETER(db);
2165   return 0;
2166 #endif
2167 }
2168 
2169 /*
2170 ** Return UTF-8 encoded English language explanation of the most recent
2171 ** error.
2172 */
2173 const char *sqlite3_errmsg(sqlite3 *db){
2174   const char *z;
2175   if( !db ){
2176     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2177   }
2178   if( !sqlite3SafetyCheckSickOrOk(db) ){
2179     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2180   }
2181   sqlite3_mutex_enter(db->mutex);
2182   if( db->mallocFailed ){
2183     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2184   }else{
2185     testcase( db->pErr==0 );
2186     z = (char*)sqlite3_value_text(db->pErr);
2187     assert( !db->mallocFailed );
2188     if( z==0 ){
2189       z = sqlite3ErrStr(db->errCode);
2190     }
2191   }
2192   sqlite3_mutex_leave(db->mutex);
2193   return z;
2194 }
2195 
2196 #ifndef SQLITE_OMIT_UTF16
2197 /*
2198 ** Return UTF-16 encoded English language explanation of the most recent
2199 ** error.
2200 */
2201 const void *sqlite3_errmsg16(sqlite3 *db){
2202   static const u16 outOfMem[] = {
2203     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2204   };
2205   static const u16 misuse[] = {
2206     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2207     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2208     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2209     'o', 'u', 't', ' ',
2210     'o', 'f', ' ',
2211     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2212   };
2213 
2214   const void *z;
2215   if( !db ){
2216     return (void *)outOfMem;
2217   }
2218   if( !sqlite3SafetyCheckSickOrOk(db) ){
2219     return (void *)misuse;
2220   }
2221   sqlite3_mutex_enter(db->mutex);
2222   if( db->mallocFailed ){
2223     z = (void *)outOfMem;
2224   }else{
2225     z = sqlite3_value_text16(db->pErr);
2226     if( z==0 ){
2227       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2228       z = sqlite3_value_text16(db->pErr);
2229     }
2230     /* A malloc() may have failed within the call to sqlite3_value_text16()
2231     ** above. If this is the case, then the db->mallocFailed flag needs to
2232     ** be cleared before returning. Do this directly, instead of via
2233     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2234     */
2235     sqlite3OomClear(db);
2236   }
2237   sqlite3_mutex_leave(db->mutex);
2238   return z;
2239 }
2240 #endif /* SQLITE_OMIT_UTF16 */
2241 
2242 /*
2243 ** Return the most recent error code generated by an SQLite routine. If NULL is
2244 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2245 */
2246 int sqlite3_errcode(sqlite3 *db){
2247   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2248     return SQLITE_MISUSE_BKPT;
2249   }
2250   if( !db || db->mallocFailed ){
2251     return SQLITE_NOMEM_BKPT;
2252   }
2253   return db->errCode & db->errMask;
2254 }
2255 int sqlite3_extended_errcode(sqlite3 *db){
2256   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2257     return SQLITE_MISUSE_BKPT;
2258   }
2259   if( !db || db->mallocFailed ){
2260     return SQLITE_NOMEM_BKPT;
2261   }
2262   return db->errCode;
2263 }
2264 int sqlite3_system_errno(sqlite3 *db){
2265   return db ? db->iSysErrno : 0;
2266 }
2267 
2268 /*
2269 ** Return a string that describes the kind of error specified in the
2270 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2271 ** function.
2272 */
2273 const char *sqlite3_errstr(int rc){
2274   return sqlite3ErrStr(rc);
2275 }
2276 
2277 /*
2278 ** Create a new collating function for database "db".  The name is zName
2279 ** and the encoding is enc.
2280 */
2281 static int createCollation(
2282   sqlite3* db,
2283   const char *zName,
2284   u8 enc,
2285   void* pCtx,
2286   int(*xCompare)(void*,int,const void*,int,const void*),
2287   void(*xDel)(void*)
2288 ){
2289   CollSeq *pColl;
2290   int enc2;
2291 
2292   assert( sqlite3_mutex_held(db->mutex) );
2293 
2294   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2295   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2296   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2297   */
2298   enc2 = enc;
2299   testcase( enc2==SQLITE_UTF16 );
2300   testcase( enc2==SQLITE_UTF16_ALIGNED );
2301   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2302     enc2 = SQLITE_UTF16NATIVE;
2303   }
2304   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2305     return SQLITE_MISUSE_BKPT;
2306   }
2307 
2308   /* Check if this call is removing or replacing an existing collation
2309   ** sequence. If so, and there are active VMs, return busy. If there
2310   ** are no active VMs, invalidate any pre-compiled statements.
2311   */
2312   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2313   if( pColl && pColl->xCmp ){
2314     if( db->nVdbeActive ){
2315       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2316         "unable to delete/modify collation sequence due to active statements");
2317       return SQLITE_BUSY;
2318     }
2319     sqlite3ExpirePreparedStatements(db);
2320 
2321     /* If collation sequence pColl was created directly by a call to
2322     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2323     ** then any copies made by synthCollSeq() need to be invalidated.
2324     ** Also, collation destructor - CollSeq.xDel() - function may need
2325     ** to be called.
2326     */
2327     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2328       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2329       int j;
2330       for(j=0; j<3; j++){
2331         CollSeq *p = &aColl[j];
2332         if( p->enc==pColl->enc ){
2333           if( p->xDel ){
2334             p->xDel(p->pUser);
2335           }
2336           p->xCmp = 0;
2337         }
2338       }
2339     }
2340   }
2341 
2342   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2343   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2344   pColl->xCmp = xCompare;
2345   pColl->pUser = pCtx;
2346   pColl->xDel = xDel;
2347   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2348   sqlite3Error(db, SQLITE_OK);
2349   return SQLITE_OK;
2350 }
2351 
2352 
2353 /*
2354 ** This array defines hard upper bounds on limit values.  The
2355 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2356 ** #defines in sqlite3.h.
2357 */
2358 static const int aHardLimit[] = {
2359   SQLITE_MAX_LENGTH,
2360   SQLITE_MAX_SQL_LENGTH,
2361   SQLITE_MAX_COLUMN,
2362   SQLITE_MAX_EXPR_DEPTH,
2363   SQLITE_MAX_COMPOUND_SELECT,
2364   SQLITE_MAX_VDBE_OP,
2365   SQLITE_MAX_FUNCTION_ARG,
2366   SQLITE_MAX_ATTACHED,
2367   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2368   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2369   SQLITE_MAX_TRIGGER_DEPTH,
2370   SQLITE_MAX_WORKER_THREADS,
2371 };
2372 
2373 /*
2374 ** Make sure the hard limits are set to reasonable values
2375 */
2376 #if SQLITE_MAX_LENGTH<100
2377 # error SQLITE_MAX_LENGTH must be at least 100
2378 #endif
2379 #if SQLITE_MAX_SQL_LENGTH<100
2380 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2381 #endif
2382 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2383 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2384 #endif
2385 #if SQLITE_MAX_COMPOUND_SELECT<2
2386 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2387 #endif
2388 #if SQLITE_MAX_VDBE_OP<40
2389 # error SQLITE_MAX_VDBE_OP must be at least 40
2390 #endif
2391 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2392 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2393 #endif
2394 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2395 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2396 #endif
2397 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2398 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2399 #endif
2400 #if SQLITE_MAX_COLUMN>32767
2401 # error SQLITE_MAX_COLUMN must not exceed 32767
2402 #endif
2403 #if SQLITE_MAX_TRIGGER_DEPTH<1
2404 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2405 #endif
2406 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2407 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2408 #endif
2409 
2410 
2411 /*
2412 ** Change the value of a limit.  Report the old value.
2413 ** If an invalid limit index is supplied, report -1.
2414 ** Make no changes but still report the old value if the
2415 ** new limit is negative.
2416 **
2417 ** A new lower limit does not shrink existing constructs.
2418 ** It merely prevents new constructs that exceed the limit
2419 ** from forming.
2420 */
2421 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2422   int oldLimit;
2423 
2424 #ifdef SQLITE_ENABLE_API_ARMOR
2425   if( !sqlite3SafetyCheckOk(db) ){
2426     (void)SQLITE_MISUSE_BKPT;
2427     return -1;
2428   }
2429 #endif
2430 
2431   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2432   ** there is a hard upper bound set at compile-time by a C preprocessor
2433   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2434   ** "_MAX_".)
2435   */
2436   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2437   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2438   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2439   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2440   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2441   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2442   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2443   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2444   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2445                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2446   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2447   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2448   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2449   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2450 
2451 
2452   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2453     return -1;
2454   }
2455   oldLimit = db->aLimit[limitId];
2456   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2457     if( newLimit>aHardLimit[limitId] ){
2458       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2459     }
2460     db->aLimit[limitId] = newLimit;
2461   }
2462   return oldLimit;                     /* IMP: R-53341-35419 */
2463 }
2464 
2465 /*
2466 ** This function is used to parse both URIs and non-URI filenames passed by the
2467 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2468 ** URIs specified as part of ATTACH statements.
2469 **
2470 ** The first argument to this function is the name of the VFS to use (or
2471 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2472 ** query parameter. The second argument contains the URI (or non-URI filename)
2473 ** itself. When this function is called the *pFlags variable should contain
2474 ** the default flags to open the database handle with. The value stored in
2475 ** *pFlags may be updated before returning if the URI filename contains
2476 ** "cache=xxx" or "mode=xxx" query parameters.
2477 **
2478 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2479 ** the VFS that should be used to open the database file. *pzFile is set to
2480 ** point to a buffer containing the name of the file to open. It is the
2481 ** responsibility of the caller to eventually call sqlite3_free() to release
2482 ** this buffer.
2483 **
2484 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2485 ** may be set to point to a buffer containing an English language error
2486 ** message. It is the responsibility of the caller to eventually release
2487 ** this buffer by calling sqlite3_free().
2488 */
2489 int sqlite3ParseUri(
2490   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2491   const char *zUri,               /* Nul-terminated URI to parse */
2492   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2493   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2494   char **pzFile,                  /* OUT: Filename component of URI */
2495   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2496 ){
2497   int rc = SQLITE_OK;
2498   unsigned int flags = *pFlags;
2499   const char *zVfs = zDefaultVfs;
2500   char *zFile;
2501   char c;
2502   int nUri = sqlite3Strlen30(zUri);
2503 
2504   assert( *pzErrMsg==0 );
2505 
2506   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2507             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2508    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2509   ){
2510     char *zOpt;
2511     int eState;                   /* Parser state when parsing URI */
2512     int iIn;                      /* Input character index */
2513     int iOut = 0;                 /* Output character index */
2514     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2515 
2516     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2517     ** method that there may be extra parameters following the file-name.  */
2518     flags |= SQLITE_OPEN_URI;
2519 
2520     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2521     zFile = sqlite3_malloc64(nByte);
2522     if( !zFile ) return SQLITE_NOMEM_BKPT;
2523 
2524     iIn = 5;
2525 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2526     if( strncmp(zUri+5, "///", 3)==0 ){
2527       iIn = 7;
2528       /* The following condition causes URIs with five leading / characters
2529       ** like file://///host/path to be converted into UNCs like //host/path.
2530       ** The correct URI for that UNC has only two or four leading / characters
2531       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2532       ** common error, we are told, so we handle it as a special case. */
2533       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2534     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2535       iIn = 16;
2536     }
2537 #else
2538     /* Discard the scheme and authority segments of the URI. */
2539     if( zUri[5]=='/' && zUri[6]=='/' ){
2540       iIn = 7;
2541       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2542       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2543         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2544             iIn-7, &zUri[7]);
2545         rc = SQLITE_ERROR;
2546         goto parse_uri_out;
2547       }
2548     }
2549 #endif
2550 
2551     /* Copy the filename and any query parameters into the zFile buffer.
2552     ** Decode %HH escape codes along the way.
2553     **
2554     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2555     ** on the parsing context. As follows:
2556     **
2557     **   0: Parsing file-name.
2558     **   1: Parsing name section of a name=value query parameter.
2559     **   2: Parsing value section of a name=value query parameter.
2560     */
2561     eState = 0;
2562     while( (c = zUri[iIn])!=0 && c!='#' ){
2563       iIn++;
2564       if( c=='%'
2565        && sqlite3Isxdigit(zUri[iIn])
2566        && sqlite3Isxdigit(zUri[iIn+1])
2567       ){
2568         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2569         octet += sqlite3HexToInt(zUri[iIn++]);
2570 
2571         assert( octet>=0 && octet<256 );
2572         if( octet==0 ){
2573           /* This branch is taken when "%00" appears within the URI. In this
2574           ** case we ignore all text in the remainder of the path, name or
2575           ** value currently being parsed. So ignore the current character
2576           ** and skip to the next "?", "=" or "&", as appropriate. */
2577           while( (c = zUri[iIn])!=0 && c!='#'
2578               && (eState!=0 || c!='?')
2579               && (eState!=1 || (c!='=' && c!='&'))
2580               && (eState!=2 || c!='&')
2581           ){
2582             iIn++;
2583           }
2584           continue;
2585         }
2586         c = octet;
2587       }else if( eState==1 && (c=='&' || c=='=') ){
2588         if( zFile[iOut-1]==0 ){
2589           /* An empty option name. Ignore this option altogether. */
2590           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2591           continue;
2592         }
2593         if( c=='&' ){
2594           zFile[iOut++] = '\0';
2595         }else{
2596           eState = 2;
2597         }
2598         c = 0;
2599       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2600         c = 0;
2601         eState = 1;
2602       }
2603       zFile[iOut++] = c;
2604     }
2605     if( eState==1 ) zFile[iOut++] = '\0';
2606     zFile[iOut++] = '\0';
2607     zFile[iOut++] = '\0';
2608 
2609     /* Check if there were any options specified that should be interpreted
2610     ** here. Options that are interpreted here include "vfs" and those that
2611     ** correspond to flags that may be passed to the sqlite3_open_v2()
2612     ** method. */
2613     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2614     while( zOpt[0] ){
2615       int nOpt = sqlite3Strlen30(zOpt);
2616       char *zVal = &zOpt[nOpt+1];
2617       int nVal = sqlite3Strlen30(zVal);
2618 
2619       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2620         zVfs = zVal;
2621       }else{
2622         struct OpenMode {
2623           const char *z;
2624           int mode;
2625         } *aMode = 0;
2626         char *zModeType = 0;
2627         int mask = 0;
2628         int limit = 0;
2629 
2630         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2631           static struct OpenMode aCacheMode[] = {
2632             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2633             { "private", SQLITE_OPEN_PRIVATECACHE },
2634             { 0, 0 }
2635           };
2636 
2637           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2638           aMode = aCacheMode;
2639           limit = mask;
2640           zModeType = "cache";
2641         }
2642         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2643           static struct OpenMode aOpenMode[] = {
2644             { "ro",  SQLITE_OPEN_READONLY },
2645             { "rw",  SQLITE_OPEN_READWRITE },
2646             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2647             { "memory", SQLITE_OPEN_MEMORY },
2648             { 0, 0 }
2649           };
2650 
2651           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2652                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2653           aMode = aOpenMode;
2654           limit = mask & flags;
2655           zModeType = "access";
2656         }
2657 
2658         if( aMode ){
2659           int i;
2660           int mode = 0;
2661           for(i=0; aMode[i].z; i++){
2662             const char *z = aMode[i].z;
2663             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2664               mode = aMode[i].mode;
2665               break;
2666             }
2667           }
2668           if( mode==0 ){
2669             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2670             rc = SQLITE_ERROR;
2671             goto parse_uri_out;
2672           }
2673           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2674             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2675                                         zModeType, zVal);
2676             rc = SQLITE_PERM;
2677             goto parse_uri_out;
2678           }
2679           flags = (flags & ~mask) | mode;
2680         }
2681       }
2682 
2683       zOpt = &zVal[nVal+1];
2684     }
2685 
2686   }else{
2687     zFile = sqlite3_malloc64(nUri+2);
2688     if( !zFile ) return SQLITE_NOMEM_BKPT;
2689     memcpy(zFile, zUri, nUri);
2690     zFile[nUri] = '\0';
2691     zFile[nUri+1] = '\0';
2692     flags &= ~SQLITE_OPEN_URI;
2693   }
2694 
2695   *ppVfs = sqlite3_vfs_find(zVfs);
2696   if( *ppVfs==0 ){
2697     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2698     rc = SQLITE_ERROR;
2699   }
2700  parse_uri_out:
2701   if( rc!=SQLITE_OK ){
2702     sqlite3_free(zFile);
2703     zFile = 0;
2704   }
2705   *pFlags = flags;
2706   *pzFile = zFile;
2707   return rc;
2708 }
2709 
2710 
2711 /*
2712 ** This routine does the work of opening a database on behalf of
2713 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2714 ** is UTF-8 encoded.
2715 */
2716 static int openDatabase(
2717   const char *zFilename, /* Database filename UTF-8 encoded */
2718   sqlite3 **ppDb,        /* OUT: Returned database handle */
2719   unsigned int flags,    /* Operational flags */
2720   const char *zVfs       /* Name of the VFS to use */
2721 ){
2722   sqlite3 *db;                    /* Store allocated handle here */
2723   int rc;                         /* Return code */
2724   int isThreadsafe;               /* True for threadsafe connections */
2725   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2726   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2727 
2728 #ifdef SQLITE_ENABLE_API_ARMOR
2729   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2730 #endif
2731   *ppDb = 0;
2732 #ifndef SQLITE_OMIT_AUTOINIT
2733   rc = sqlite3_initialize();
2734   if( rc ) return rc;
2735 #endif
2736 
2737   /* Only allow sensible combinations of bits in the flags argument.
2738   ** Throw an error if any non-sense combination is used.  If we
2739   ** do not block illegal combinations here, it could trigger
2740   ** assert() statements in deeper layers.  Sensible combinations
2741   ** are:
2742   **
2743   **  1:  SQLITE_OPEN_READONLY
2744   **  2:  SQLITE_OPEN_READWRITE
2745   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2746   */
2747   assert( SQLITE_OPEN_READONLY  == 0x01 );
2748   assert( SQLITE_OPEN_READWRITE == 0x02 );
2749   assert( SQLITE_OPEN_CREATE    == 0x04 );
2750   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2751   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2752   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2753   if( ((1<<(flags&7)) & 0x46)==0 ){
2754     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2755   }
2756 
2757   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2758     isThreadsafe = 0;
2759   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2760     isThreadsafe = 0;
2761   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2762     isThreadsafe = 1;
2763   }else{
2764     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2765   }
2766   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2767     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2768   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2769     flags |= SQLITE_OPEN_SHAREDCACHE;
2770   }
2771 
2772   /* Remove harmful bits from the flags parameter
2773   **
2774   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2775   ** dealt with in the previous code block.  Besides these, the only
2776   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2777   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2778   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2779   ** off all other flags.
2780   */
2781   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2782                SQLITE_OPEN_EXCLUSIVE |
2783                SQLITE_OPEN_MAIN_DB |
2784                SQLITE_OPEN_TEMP_DB |
2785                SQLITE_OPEN_TRANSIENT_DB |
2786                SQLITE_OPEN_MAIN_JOURNAL |
2787                SQLITE_OPEN_TEMP_JOURNAL |
2788                SQLITE_OPEN_SUBJOURNAL |
2789                SQLITE_OPEN_MASTER_JOURNAL |
2790                SQLITE_OPEN_NOMUTEX |
2791                SQLITE_OPEN_FULLMUTEX |
2792                SQLITE_OPEN_WAL
2793              );
2794 
2795   /* Allocate the sqlite data structure */
2796   db = sqlite3MallocZero( sizeof(sqlite3) );
2797   if( db==0 ) goto opendb_out;
2798   if( isThreadsafe ){
2799     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2800     if( db->mutex==0 ){
2801       sqlite3_free(db);
2802       db = 0;
2803       goto opendb_out;
2804     }
2805   }
2806   sqlite3_mutex_enter(db->mutex);
2807   db->errMask = 0xff;
2808   db->nDb = 2;
2809   db->magic = SQLITE_MAGIC_BUSY;
2810   db->aDb = db->aDbStatic;
2811 
2812   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2813   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2814   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2815   db->autoCommit = 1;
2816   db->nextAutovac = -1;
2817   db->szMmap = sqlite3GlobalConfig.szMmap;
2818   db->nextPagesize = 0;
2819   db->nMaxSorterMmap = 0x7FFFFFFF;
2820   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2821 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2822                  | SQLITE_AutoIndex
2823 #endif
2824 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2825                  | SQLITE_CkptFullFSync
2826 #endif
2827 #if SQLITE_DEFAULT_FILE_FORMAT<4
2828                  | SQLITE_LegacyFileFmt
2829 #endif
2830 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2831                  | SQLITE_LoadExtension
2832 #endif
2833 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2834                  | SQLITE_RecTriggers
2835 #endif
2836 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2837                  | SQLITE_ForeignKeys
2838 #endif
2839 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2840                  | SQLITE_ReverseOrder
2841 #endif
2842 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2843                  | SQLITE_CellSizeCk
2844 #endif
2845 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
2846                  | SQLITE_Fts3Tokenizer
2847 #endif
2848       ;
2849   sqlite3HashInit(&db->aCollSeq);
2850 #ifndef SQLITE_OMIT_VIRTUALTABLE
2851   sqlite3HashInit(&db->aModule);
2852 #endif
2853 
2854   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2855   ** and UTF-16, so add a version for each to avoid any unnecessary
2856   ** conversions. The only error that can occur here is a malloc() failure.
2857   **
2858   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2859   ** functions:
2860   */
2861   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2862   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2863   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2864   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2865   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2866   if( db->mallocFailed ){
2867     goto opendb_out;
2868   }
2869   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2870   ** strings is BINARY.
2871   */
2872   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2873   assert( db->pDfltColl!=0 );
2874 
2875   /* Parse the filename/URI argument. */
2876   db->openFlags = flags;
2877   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2878   if( rc!=SQLITE_OK ){
2879     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2880     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2881     sqlite3_free(zErrMsg);
2882     goto opendb_out;
2883   }
2884 
2885   /* Open the backend database driver */
2886   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2887                         flags | SQLITE_OPEN_MAIN_DB);
2888   if( rc!=SQLITE_OK ){
2889     if( rc==SQLITE_IOERR_NOMEM ){
2890       rc = SQLITE_NOMEM_BKPT;
2891     }
2892     sqlite3Error(db, rc);
2893     goto opendb_out;
2894   }
2895   sqlite3BtreeEnter(db->aDb[0].pBt);
2896   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2897   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2898   sqlite3BtreeLeave(db->aDb[0].pBt);
2899   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2900 
2901   /* The default safety_level for the main database is FULL; for the temp
2902   ** database it is OFF. This matches the pager layer defaults.
2903   */
2904   db->aDb[0].zName = "main";
2905   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
2906   db->aDb[1].zName = "temp";
2907   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
2908 
2909   db->magic = SQLITE_MAGIC_OPEN;
2910   if( db->mallocFailed ){
2911     goto opendb_out;
2912   }
2913 
2914   /* Register all built-in functions, but do not attempt to read the
2915   ** database schema yet. This is delayed until the first time the database
2916   ** is accessed.
2917   */
2918   sqlite3Error(db, SQLITE_OK);
2919   sqlite3RegisterPerConnectionBuiltinFunctions(db);
2920 
2921   /* Load automatic extensions - extensions that have been registered
2922   ** using the sqlite3_automatic_extension() API.
2923   */
2924   rc = sqlite3_errcode(db);
2925   if( rc==SQLITE_OK ){
2926     sqlite3AutoLoadExtensions(db);
2927     rc = sqlite3_errcode(db);
2928     if( rc!=SQLITE_OK ){
2929       goto opendb_out;
2930     }
2931   }
2932 
2933 #ifdef SQLITE_ENABLE_FTS1
2934   if( !db->mallocFailed ){
2935     extern int sqlite3Fts1Init(sqlite3*);
2936     rc = sqlite3Fts1Init(db);
2937   }
2938 #endif
2939 
2940 #ifdef SQLITE_ENABLE_FTS2
2941   if( !db->mallocFailed && rc==SQLITE_OK ){
2942     extern int sqlite3Fts2Init(sqlite3*);
2943     rc = sqlite3Fts2Init(db);
2944   }
2945 #endif
2946 
2947 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
2948   if( !db->mallocFailed && rc==SQLITE_OK ){
2949     rc = sqlite3Fts3Init(db);
2950   }
2951 #endif
2952 
2953 #ifdef SQLITE_ENABLE_FTS5
2954   if( !db->mallocFailed && rc==SQLITE_OK ){
2955     rc = sqlite3Fts5Init(db);
2956   }
2957 #endif
2958 
2959 #ifdef SQLITE_ENABLE_ICU
2960   if( !db->mallocFailed && rc==SQLITE_OK ){
2961     rc = sqlite3IcuInit(db);
2962   }
2963 #endif
2964 
2965 #ifdef SQLITE_ENABLE_RTREE
2966   if( !db->mallocFailed && rc==SQLITE_OK){
2967     rc = sqlite3RtreeInit(db);
2968   }
2969 #endif
2970 
2971 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
2972   if( !db->mallocFailed && rc==SQLITE_OK){
2973     rc = sqlite3DbstatRegister(db);
2974   }
2975 #endif
2976 
2977 #ifdef SQLITE_ENABLE_JSON1
2978   if( !db->mallocFailed && rc==SQLITE_OK){
2979     rc = sqlite3Json1Init(db);
2980   }
2981 #endif
2982 
2983   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2984   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2985   ** mode.  Doing nothing at all also makes NORMAL the default.
2986   */
2987 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2988   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2989   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2990                           SQLITE_DEFAULT_LOCKING_MODE);
2991 #endif
2992 
2993   if( rc ) sqlite3Error(db, rc);
2994 
2995   /* Enable the lookaside-malloc subsystem */
2996   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2997                         sqlite3GlobalConfig.nLookaside);
2998 
2999   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3000 
3001 opendb_out:
3002   if( db ){
3003     assert( db->mutex!=0 || isThreadsafe==0
3004            || sqlite3GlobalConfig.bFullMutex==0 );
3005     sqlite3_mutex_leave(db->mutex);
3006   }
3007   rc = sqlite3_errcode(db);
3008   assert( db!=0 || rc==SQLITE_NOMEM );
3009   if( rc==SQLITE_NOMEM ){
3010     sqlite3_close(db);
3011     db = 0;
3012   }else if( rc!=SQLITE_OK ){
3013     db->magic = SQLITE_MAGIC_SICK;
3014   }
3015   *ppDb = db;
3016 #ifdef SQLITE_ENABLE_SQLLOG
3017   if( sqlite3GlobalConfig.xSqllog ){
3018     /* Opening a db handle. Fourth parameter is passed 0. */
3019     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3020     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3021   }
3022 #endif
3023 #if defined(SQLITE_HAS_CODEC)
3024   if( rc==SQLITE_OK ){
3025     const char *zHexKey = sqlite3_uri_parameter(zOpen, "hexkey");
3026     if( zHexKey && zHexKey[0] ){
3027       u8 iByte;
3028       int i;
3029       char zKey[40];
3030       for(i=0, iByte=0; i<sizeof(zKey)*2 && sqlite3Isxdigit(zHexKey[i]); i++){
3031         iByte = (iByte<<4) + sqlite3HexToInt(zHexKey[i]);
3032         if( (i&1)!=0 ) zKey[i/2] = iByte;
3033       }
3034       sqlite3_key_v2(db, 0, zKey, i/2);
3035     }
3036   }
3037 #endif
3038   sqlite3_free(zOpen);
3039   return rc & 0xff;
3040 }
3041 
3042 /*
3043 ** Open a new database handle.
3044 */
3045 int sqlite3_open(
3046   const char *zFilename,
3047   sqlite3 **ppDb
3048 ){
3049   return openDatabase(zFilename, ppDb,
3050                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3051 }
3052 int sqlite3_open_v2(
3053   const char *filename,   /* Database filename (UTF-8) */
3054   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3055   int flags,              /* Flags */
3056   const char *zVfs        /* Name of VFS module to use */
3057 ){
3058   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3059 }
3060 
3061 #ifndef SQLITE_OMIT_UTF16
3062 /*
3063 ** Open a new database handle.
3064 */
3065 int sqlite3_open16(
3066   const void *zFilename,
3067   sqlite3 **ppDb
3068 ){
3069   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3070   sqlite3_value *pVal;
3071   int rc;
3072 
3073 #ifdef SQLITE_ENABLE_API_ARMOR
3074   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3075 #endif
3076   *ppDb = 0;
3077 #ifndef SQLITE_OMIT_AUTOINIT
3078   rc = sqlite3_initialize();
3079   if( rc ) return rc;
3080 #endif
3081   if( zFilename==0 ) zFilename = "\000\000";
3082   pVal = sqlite3ValueNew(0);
3083   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3084   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3085   if( zFilename8 ){
3086     rc = openDatabase(zFilename8, ppDb,
3087                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3088     assert( *ppDb || rc==SQLITE_NOMEM );
3089     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3090       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3091     }
3092   }else{
3093     rc = SQLITE_NOMEM_BKPT;
3094   }
3095   sqlite3ValueFree(pVal);
3096 
3097   return rc & 0xff;
3098 }
3099 #endif /* SQLITE_OMIT_UTF16 */
3100 
3101 /*
3102 ** Register a new collation sequence with the database handle db.
3103 */
3104 int sqlite3_create_collation(
3105   sqlite3* db,
3106   const char *zName,
3107   int enc,
3108   void* pCtx,
3109   int(*xCompare)(void*,int,const void*,int,const void*)
3110 ){
3111   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3112 }
3113 
3114 /*
3115 ** Register a new collation sequence with the database handle db.
3116 */
3117 int sqlite3_create_collation_v2(
3118   sqlite3* db,
3119   const char *zName,
3120   int enc,
3121   void* pCtx,
3122   int(*xCompare)(void*,int,const void*,int,const void*),
3123   void(*xDel)(void*)
3124 ){
3125   int rc;
3126 
3127 #ifdef SQLITE_ENABLE_API_ARMOR
3128   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3129 #endif
3130   sqlite3_mutex_enter(db->mutex);
3131   assert( !db->mallocFailed );
3132   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3133   rc = sqlite3ApiExit(db, rc);
3134   sqlite3_mutex_leave(db->mutex);
3135   return rc;
3136 }
3137 
3138 #ifndef SQLITE_OMIT_UTF16
3139 /*
3140 ** Register a new collation sequence with the database handle db.
3141 */
3142 int sqlite3_create_collation16(
3143   sqlite3* db,
3144   const void *zName,
3145   int enc,
3146   void* pCtx,
3147   int(*xCompare)(void*,int,const void*,int,const void*)
3148 ){
3149   int rc = SQLITE_OK;
3150   char *zName8;
3151 
3152 #ifdef SQLITE_ENABLE_API_ARMOR
3153   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3154 #endif
3155   sqlite3_mutex_enter(db->mutex);
3156   assert( !db->mallocFailed );
3157   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3158   if( zName8 ){
3159     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3160     sqlite3DbFree(db, zName8);
3161   }
3162   rc = sqlite3ApiExit(db, rc);
3163   sqlite3_mutex_leave(db->mutex);
3164   return rc;
3165 }
3166 #endif /* SQLITE_OMIT_UTF16 */
3167 
3168 /*
3169 ** Register a collation sequence factory callback with the database handle
3170 ** db. Replace any previously installed collation sequence factory.
3171 */
3172 int sqlite3_collation_needed(
3173   sqlite3 *db,
3174   void *pCollNeededArg,
3175   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3176 ){
3177 #ifdef SQLITE_ENABLE_API_ARMOR
3178   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3179 #endif
3180   sqlite3_mutex_enter(db->mutex);
3181   db->xCollNeeded = xCollNeeded;
3182   db->xCollNeeded16 = 0;
3183   db->pCollNeededArg = pCollNeededArg;
3184   sqlite3_mutex_leave(db->mutex);
3185   return SQLITE_OK;
3186 }
3187 
3188 #ifndef SQLITE_OMIT_UTF16
3189 /*
3190 ** Register a collation sequence factory callback with the database handle
3191 ** db. Replace any previously installed collation sequence factory.
3192 */
3193 int sqlite3_collation_needed16(
3194   sqlite3 *db,
3195   void *pCollNeededArg,
3196   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3197 ){
3198 #ifdef SQLITE_ENABLE_API_ARMOR
3199   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3200 #endif
3201   sqlite3_mutex_enter(db->mutex);
3202   db->xCollNeeded = 0;
3203   db->xCollNeeded16 = xCollNeeded16;
3204   db->pCollNeededArg = pCollNeededArg;
3205   sqlite3_mutex_leave(db->mutex);
3206   return SQLITE_OK;
3207 }
3208 #endif /* SQLITE_OMIT_UTF16 */
3209 
3210 #ifndef SQLITE_OMIT_DEPRECATED
3211 /*
3212 ** This function is now an anachronism. It used to be used to recover from a
3213 ** malloc() failure, but SQLite now does this automatically.
3214 */
3215 int sqlite3_global_recover(void){
3216   return SQLITE_OK;
3217 }
3218 #endif
3219 
3220 /*
3221 ** Test to see whether or not the database connection is in autocommit
3222 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3223 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3224 ** by the next COMMIT or ROLLBACK.
3225 */
3226 int sqlite3_get_autocommit(sqlite3 *db){
3227 #ifdef SQLITE_ENABLE_API_ARMOR
3228   if( !sqlite3SafetyCheckOk(db) ){
3229     (void)SQLITE_MISUSE_BKPT;
3230     return 0;
3231   }
3232 #endif
3233   return db->autoCommit;
3234 }
3235 
3236 /*
3237 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3238 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3239 ** constants.  They serve two purposes:
3240 **
3241 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3242 **       to detect when version error conditions occurs.
3243 **
3244 **   2.  Invoke sqlite3_log() to provide the source code location where
3245 **       a low-level error is first detected.
3246 */
3247 static int reportError(int iErr, int lineno, const char *zType){
3248   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3249               zType, lineno, 20+sqlite3_sourceid());
3250   return iErr;
3251 }
3252 int sqlite3CorruptError(int lineno){
3253   testcase( sqlite3GlobalConfig.xLog!=0 );
3254   return reportError(SQLITE_CORRUPT, lineno, "database corruption");
3255 }
3256 int sqlite3MisuseError(int lineno){
3257   testcase( sqlite3GlobalConfig.xLog!=0 );
3258   return reportError(SQLITE_MISUSE, lineno, "misuse");
3259 }
3260 int sqlite3CantopenError(int lineno){
3261   testcase( sqlite3GlobalConfig.xLog!=0 );
3262   return reportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3263 }
3264 #ifdef SQLITE_DEBUG
3265 int sqlite3NomemError(int lineno){
3266   testcase( sqlite3GlobalConfig.xLog!=0 );
3267   return reportError(SQLITE_NOMEM, lineno, "OOM");
3268 }
3269 int sqlite3IoerrnomemError(int lineno){
3270   testcase( sqlite3GlobalConfig.xLog!=0 );
3271   return reportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3272 }
3273 #endif
3274 
3275 #ifndef SQLITE_OMIT_DEPRECATED
3276 /*
3277 ** This is a convenience routine that makes sure that all thread-specific
3278 ** data for this thread has been deallocated.
3279 **
3280 ** SQLite no longer uses thread-specific data so this routine is now a
3281 ** no-op.  It is retained for historical compatibility.
3282 */
3283 void sqlite3_thread_cleanup(void){
3284 }
3285 #endif
3286 
3287 /*
3288 ** Return meta information about a specific column of a database table.
3289 ** See comment in sqlite3.h (sqlite.h.in) for details.
3290 */
3291 int sqlite3_table_column_metadata(
3292   sqlite3 *db,                /* Connection handle */
3293   const char *zDbName,        /* Database name or NULL */
3294   const char *zTableName,     /* Table name */
3295   const char *zColumnName,    /* Column name */
3296   char const **pzDataType,    /* OUTPUT: Declared data type */
3297   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3298   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3299   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3300   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3301 ){
3302   int rc;
3303   char *zErrMsg = 0;
3304   Table *pTab = 0;
3305   Column *pCol = 0;
3306   int iCol = 0;
3307   char const *zDataType = 0;
3308   char const *zCollSeq = 0;
3309   int notnull = 0;
3310   int primarykey = 0;
3311   int autoinc = 0;
3312 
3313 
3314 #ifdef SQLITE_ENABLE_API_ARMOR
3315   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3316     return SQLITE_MISUSE_BKPT;
3317   }
3318 #endif
3319 
3320   /* Ensure the database schema has been loaded */
3321   sqlite3_mutex_enter(db->mutex);
3322   sqlite3BtreeEnterAll(db);
3323   rc = sqlite3Init(db, &zErrMsg);
3324   if( SQLITE_OK!=rc ){
3325     goto error_out;
3326   }
3327 
3328   /* Locate the table in question */
3329   pTab = sqlite3FindTable(db, zTableName, zDbName);
3330   if( !pTab || pTab->pSelect ){
3331     pTab = 0;
3332     goto error_out;
3333   }
3334 
3335   /* Find the column for which info is requested */
3336   if( zColumnName==0 ){
3337     /* Query for existance of table only */
3338   }else{
3339     for(iCol=0; iCol<pTab->nCol; iCol++){
3340       pCol = &pTab->aCol[iCol];
3341       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3342         break;
3343       }
3344     }
3345     if( iCol==pTab->nCol ){
3346       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3347         iCol = pTab->iPKey;
3348         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3349       }else{
3350         pTab = 0;
3351         goto error_out;
3352       }
3353     }
3354   }
3355 
3356   /* The following block stores the meta information that will be returned
3357   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3358   ** and autoinc. At this point there are two possibilities:
3359   **
3360   **     1. The specified column name was rowid", "oid" or "_rowid_"
3361   **        and there is no explicitly declared IPK column.
3362   **
3363   **     2. The table is not a view and the column name identified an
3364   **        explicitly declared column. Copy meta information from *pCol.
3365   */
3366   if( pCol ){
3367     zDataType = sqlite3ColumnType(pCol,0);
3368     zCollSeq = pCol->zColl;
3369     notnull = pCol->notNull!=0;
3370     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3371     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3372   }else{
3373     zDataType = "INTEGER";
3374     primarykey = 1;
3375   }
3376   if( !zCollSeq ){
3377     zCollSeq = sqlite3StrBINARY;
3378   }
3379 
3380 error_out:
3381   sqlite3BtreeLeaveAll(db);
3382 
3383   /* Whether the function call succeeded or failed, set the output parameters
3384   ** to whatever their local counterparts contain. If an error did occur,
3385   ** this has the effect of zeroing all output parameters.
3386   */
3387   if( pzDataType ) *pzDataType = zDataType;
3388   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3389   if( pNotNull ) *pNotNull = notnull;
3390   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3391   if( pAutoinc ) *pAutoinc = autoinc;
3392 
3393   if( SQLITE_OK==rc && !pTab ){
3394     sqlite3DbFree(db, zErrMsg);
3395     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3396         zColumnName);
3397     rc = SQLITE_ERROR;
3398   }
3399   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3400   sqlite3DbFree(db, zErrMsg);
3401   rc = sqlite3ApiExit(db, rc);
3402   sqlite3_mutex_leave(db->mutex);
3403   return rc;
3404 }
3405 
3406 /*
3407 ** Sleep for a little while.  Return the amount of time slept.
3408 */
3409 int sqlite3_sleep(int ms){
3410   sqlite3_vfs *pVfs;
3411   int rc;
3412   pVfs = sqlite3_vfs_find(0);
3413   if( pVfs==0 ) return 0;
3414 
3415   /* This function works in milliseconds, but the underlying OsSleep()
3416   ** API uses microseconds. Hence the 1000's.
3417   */
3418   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3419   return rc;
3420 }
3421 
3422 /*
3423 ** Enable or disable the extended result codes.
3424 */
3425 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3426 #ifdef SQLITE_ENABLE_API_ARMOR
3427   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3428 #endif
3429   sqlite3_mutex_enter(db->mutex);
3430   db->errMask = onoff ? 0xffffffff : 0xff;
3431   sqlite3_mutex_leave(db->mutex);
3432   return SQLITE_OK;
3433 }
3434 
3435 /*
3436 ** Invoke the xFileControl method on a particular database.
3437 */
3438 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3439   int rc = SQLITE_ERROR;
3440   Btree *pBtree;
3441 
3442 #ifdef SQLITE_ENABLE_API_ARMOR
3443   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3444 #endif
3445   sqlite3_mutex_enter(db->mutex);
3446   pBtree = sqlite3DbNameToBtree(db, zDbName);
3447   if( pBtree ){
3448     Pager *pPager;
3449     sqlite3_file *fd;
3450     sqlite3BtreeEnter(pBtree);
3451     pPager = sqlite3BtreePager(pBtree);
3452     assert( pPager!=0 );
3453     fd = sqlite3PagerFile(pPager);
3454     assert( fd!=0 );
3455     if( op==SQLITE_FCNTL_FILE_POINTER ){
3456       *(sqlite3_file**)pArg = fd;
3457       rc = SQLITE_OK;
3458     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3459       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3460       rc = SQLITE_OK;
3461     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3462       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3463       rc = SQLITE_OK;
3464     }else if( fd->pMethods ){
3465       rc = sqlite3OsFileControl(fd, op, pArg);
3466     }else{
3467       rc = SQLITE_NOTFOUND;
3468     }
3469     sqlite3BtreeLeave(pBtree);
3470   }
3471   sqlite3_mutex_leave(db->mutex);
3472   return rc;
3473 }
3474 
3475 /*
3476 ** Interface to the testing logic.
3477 */
3478 int sqlite3_test_control(int op, ...){
3479   int rc = 0;
3480 #ifdef SQLITE_OMIT_BUILTIN_TEST
3481   UNUSED_PARAMETER(op);
3482 #else
3483   va_list ap;
3484   va_start(ap, op);
3485   switch( op ){
3486 
3487     /*
3488     ** Save the current state of the PRNG.
3489     */
3490     case SQLITE_TESTCTRL_PRNG_SAVE: {
3491       sqlite3PrngSaveState();
3492       break;
3493     }
3494 
3495     /*
3496     ** Restore the state of the PRNG to the last state saved using
3497     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3498     ** this verb acts like PRNG_RESET.
3499     */
3500     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3501       sqlite3PrngRestoreState();
3502       break;
3503     }
3504 
3505     /*
3506     ** Reset the PRNG back to its uninitialized state.  The next call
3507     ** to sqlite3_randomness() will reseed the PRNG using a single call
3508     ** to the xRandomness method of the default VFS.
3509     */
3510     case SQLITE_TESTCTRL_PRNG_RESET: {
3511       sqlite3_randomness(0,0);
3512       break;
3513     }
3514 
3515     /*
3516     **  sqlite3_test_control(BITVEC_TEST, size, program)
3517     **
3518     ** Run a test against a Bitvec object of size.  The program argument
3519     ** is an array of integers that defines the test.  Return -1 on a
3520     ** memory allocation error, 0 on success, or non-zero for an error.
3521     ** See the sqlite3BitvecBuiltinTest() for additional information.
3522     */
3523     case SQLITE_TESTCTRL_BITVEC_TEST: {
3524       int sz = va_arg(ap, int);
3525       int *aProg = va_arg(ap, int*);
3526       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3527       break;
3528     }
3529 
3530     /*
3531     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3532     **
3533     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3534     ** if xCallback is not NULL.
3535     **
3536     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3537     ** is called immediately after installing the new callback and the return
3538     ** value from sqlite3FaultSim(0) becomes the return from
3539     ** sqlite3_test_control().
3540     */
3541     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3542       /* MSVC is picky about pulling func ptrs from va lists.
3543       ** http://support.microsoft.com/kb/47961
3544       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3545       */
3546       typedef int(*TESTCALLBACKFUNC_t)(int);
3547       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3548       rc = sqlite3FaultSim(0);
3549       break;
3550     }
3551 
3552     /*
3553     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3554     **
3555     ** Register hooks to call to indicate which malloc() failures
3556     ** are benign.
3557     */
3558     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3559       typedef void (*void_function)(void);
3560       void_function xBenignBegin;
3561       void_function xBenignEnd;
3562       xBenignBegin = va_arg(ap, void_function);
3563       xBenignEnd = va_arg(ap, void_function);
3564       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3565       break;
3566     }
3567 
3568     /*
3569     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3570     **
3571     ** Set the PENDING byte to the value in the argument, if X>0.
3572     ** Make no changes if X==0.  Return the value of the pending byte
3573     ** as it existing before this routine was called.
3574     **
3575     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3576     ** an incompatible database file format.  Changing the PENDING byte
3577     ** while any database connection is open results in undefined and
3578     ** deleterious behavior.
3579     */
3580     case SQLITE_TESTCTRL_PENDING_BYTE: {
3581       rc = PENDING_BYTE;
3582 #ifndef SQLITE_OMIT_WSD
3583       {
3584         unsigned int newVal = va_arg(ap, unsigned int);
3585         if( newVal ) sqlite3PendingByte = newVal;
3586       }
3587 #endif
3588       break;
3589     }
3590 
3591     /*
3592     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3593     **
3594     ** This action provides a run-time test to see whether or not
3595     ** assert() was enabled at compile-time.  If X is true and assert()
3596     ** is enabled, then the return value is true.  If X is true and
3597     ** assert() is disabled, then the return value is zero.  If X is
3598     ** false and assert() is enabled, then the assertion fires and the
3599     ** process aborts.  If X is false and assert() is disabled, then the
3600     ** return value is zero.
3601     */
3602     case SQLITE_TESTCTRL_ASSERT: {
3603       volatile int x = 0;
3604       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3605       rc = x;
3606       break;
3607     }
3608 
3609 
3610     /*
3611     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3612     **
3613     ** This action provides a run-time test to see how the ALWAYS and
3614     ** NEVER macros were defined at compile-time.
3615     **
3616     ** The return value is ALWAYS(X).
3617     **
3618     ** The recommended test is X==2.  If the return value is 2, that means
3619     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3620     ** default setting.  If the return value is 1, then ALWAYS() is either
3621     ** hard-coded to true or else it asserts if its argument is false.
3622     ** The first behavior (hard-coded to true) is the case if
3623     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3624     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3625     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3626     **
3627     ** The run-time test procedure might look something like this:
3628     **
3629     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3630     **      // ALWAYS() and NEVER() are no-op pass-through macros
3631     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3632     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3633     **    }else{
3634     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3635     **    }
3636     */
3637     case SQLITE_TESTCTRL_ALWAYS: {
3638       int x = va_arg(ap,int);
3639       rc = ALWAYS(x);
3640       break;
3641     }
3642 
3643     /*
3644     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3645     **
3646     ** The integer returned reveals the byte-order of the computer on which
3647     ** SQLite is running:
3648     **
3649     **       1     big-endian,    determined at run-time
3650     **      10     little-endian, determined at run-time
3651     **  432101     big-endian,    determined at compile-time
3652     **  123410     little-endian, determined at compile-time
3653     */
3654     case SQLITE_TESTCTRL_BYTEORDER: {
3655       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3656       break;
3657     }
3658 
3659     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3660     **
3661     ** Set the nReserve size to N for the main database on the database
3662     ** connection db.
3663     */
3664     case SQLITE_TESTCTRL_RESERVE: {
3665       sqlite3 *db = va_arg(ap, sqlite3*);
3666       int x = va_arg(ap,int);
3667       sqlite3_mutex_enter(db->mutex);
3668       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3669       sqlite3_mutex_leave(db->mutex);
3670       break;
3671     }
3672 
3673     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3674     **
3675     ** Enable or disable various optimizations for testing purposes.  The
3676     ** argument N is a bitmask of optimizations to be disabled.  For normal
3677     ** operation N should be 0.  The idea is that a test program (like the
3678     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3679     ** with various optimizations disabled to verify that the same answer
3680     ** is obtained in every case.
3681     */
3682     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3683       sqlite3 *db = va_arg(ap, sqlite3*);
3684       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3685       break;
3686     }
3687 
3688 #ifdef SQLITE_N_KEYWORD
3689     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3690     **
3691     ** If zWord is a keyword recognized by the parser, then return the
3692     ** number of keywords.  Or if zWord is not a keyword, return 0.
3693     **
3694     ** This test feature is only available in the amalgamation since
3695     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3696     ** is built using separate source files.
3697     */
3698     case SQLITE_TESTCTRL_ISKEYWORD: {
3699       const char *zWord = va_arg(ap, const char*);
3700       int n = sqlite3Strlen30(zWord);
3701       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3702       break;
3703     }
3704 #endif
3705 
3706     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3707     **
3708     ** Pass pFree into sqlite3ScratchFree().
3709     ** If sz>0 then allocate a scratch buffer into pNew.
3710     */
3711     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3712       void *pFree, **ppNew;
3713       int sz;
3714       sz = va_arg(ap, int);
3715       ppNew = va_arg(ap, void**);
3716       pFree = va_arg(ap, void*);
3717       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3718       sqlite3ScratchFree(pFree);
3719       break;
3720     }
3721 
3722     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3723     **
3724     ** If parameter onoff is non-zero, configure the wrappers so that all
3725     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3726     ** undo this setting.
3727     */
3728     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3729       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3730       break;
3731     }
3732 
3733     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3734     **
3735     ** Set or clear a flag that indicates that the database file is always well-
3736     ** formed and never corrupt.  This flag is clear by default, indicating that
3737     ** database files might have arbitrary corruption.  Setting the flag during
3738     ** testing causes certain assert() statements in the code to be activated
3739     ** that demonstrat invariants on well-formed database files.
3740     */
3741     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3742       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3743       break;
3744     }
3745 
3746 
3747     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3748     **
3749     ** Set the VDBE coverage callback function to xCallback with context
3750     ** pointer ptr.
3751     */
3752     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3753 #ifdef SQLITE_VDBE_COVERAGE
3754       typedef void (*branch_callback)(void*,int,u8,u8);
3755       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3756       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3757 #endif
3758       break;
3759     }
3760 
3761     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3762     case SQLITE_TESTCTRL_SORTER_MMAP: {
3763       sqlite3 *db = va_arg(ap, sqlite3*);
3764       db->nMaxSorterMmap = va_arg(ap, int);
3765       break;
3766     }
3767 
3768     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3769     **
3770     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3771     ** not.
3772     */
3773     case SQLITE_TESTCTRL_ISINIT: {
3774       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3775       break;
3776     }
3777 
3778     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3779     **
3780     ** This test control is used to create imposter tables.  "db" is a pointer
3781     ** to the database connection.  dbName is the database name (ex: "main" or
3782     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3783     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3784     ** table should connect.
3785     **
3786     ** Enable imposter mode only when the schema has already been parsed.  Then
3787     ** run a single CREATE TABLE statement to construct the imposter table in
3788     ** the parsed schema.  Then turn imposter mode back off again.
3789     **
3790     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3791     ** the schema to be reparsed the next time it is needed.  This has the
3792     ** effect of erasing all imposter tables.
3793     */
3794     case SQLITE_TESTCTRL_IMPOSTER: {
3795       sqlite3 *db = va_arg(ap, sqlite3*);
3796       sqlite3_mutex_enter(db->mutex);
3797       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3798       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3799       db->init.newTnum = va_arg(ap,int);
3800       if( db->init.busy==0 && db->init.newTnum>0 ){
3801         sqlite3ResetAllSchemasOfConnection(db);
3802       }
3803       sqlite3_mutex_leave(db->mutex);
3804       break;
3805     }
3806   }
3807   va_end(ap);
3808 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3809   return rc;
3810 }
3811 
3812 /*
3813 ** This is a utility routine, useful to VFS implementations, that checks
3814 ** to see if a database file was a URI that contained a specific query
3815 ** parameter, and if so obtains the value of the query parameter.
3816 **
3817 ** The zFilename argument is the filename pointer passed into the xOpen()
3818 ** method of a VFS implementation.  The zParam argument is the name of the
3819 ** query parameter we seek.  This routine returns the value of the zParam
3820 ** parameter if it exists.  If the parameter does not exist, this routine
3821 ** returns a NULL pointer.
3822 */
3823 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3824   if( zFilename==0 || zParam==0 ) return 0;
3825   zFilename += sqlite3Strlen30(zFilename) + 1;
3826   while( zFilename[0] ){
3827     int x = strcmp(zFilename, zParam);
3828     zFilename += sqlite3Strlen30(zFilename) + 1;
3829     if( x==0 ) return zFilename;
3830     zFilename += sqlite3Strlen30(zFilename) + 1;
3831   }
3832   return 0;
3833 }
3834 
3835 /*
3836 ** Return a boolean value for a query parameter.
3837 */
3838 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3839   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3840   bDflt = bDflt!=0;
3841   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3842 }
3843 
3844 /*
3845 ** Return a 64-bit integer value for a query parameter.
3846 */
3847 sqlite3_int64 sqlite3_uri_int64(
3848   const char *zFilename,    /* Filename as passed to xOpen */
3849   const char *zParam,       /* URI parameter sought */
3850   sqlite3_int64 bDflt       /* return if parameter is missing */
3851 ){
3852   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3853   sqlite3_int64 v;
3854   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3855     bDflt = v;
3856   }
3857   return bDflt;
3858 }
3859 
3860 /*
3861 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3862 */
3863 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3864   int i;
3865   for(i=0; i<db->nDb; i++){
3866     if( db->aDb[i].pBt
3867      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3868     ){
3869       return db->aDb[i].pBt;
3870     }
3871   }
3872   return 0;
3873 }
3874 
3875 /*
3876 ** Return the filename of the database associated with a database
3877 ** connection.
3878 */
3879 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3880   Btree *pBt;
3881 #ifdef SQLITE_ENABLE_API_ARMOR
3882   if( !sqlite3SafetyCheckOk(db) ){
3883     (void)SQLITE_MISUSE_BKPT;
3884     return 0;
3885   }
3886 #endif
3887   pBt = sqlite3DbNameToBtree(db, zDbName);
3888   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3889 }
3890 
3891 /*
3892 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3893 ** no such database exists.
3894 */
3895 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3896   Btree *pBt;
3897 #ifdef SQLITE_ENABLE_API_ARMOR
3898   if( !sqlite3SafetyCheckOk(db) ){
3899     (void)SQLITE_MISUSE_BKPT;
3900     return -1;
3901   }
3902 #endif
3903   pBt = sqlite3DbNameToBtree(db, zDbName);
3904   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3905 }
3906 
3907 #ifdef SQLITE_ENABLE_SNAPSHOT
3908 /*
3909 ** Obtain a snapshot handle for the snapshot of database zDb currently
3910 ** being read by handle db.
3911 */
3912 int sqlite3_snapshot_get(
3913   sqlite3 *db,
3914   const char *zDb,
3915   sqlite3_snapshot **ppSnapshot
3916 ){
3917   int rc = SQLITE_ERROR;
3918 #ifndef SQLITE_OMIT_WAL
3919   int iDb;
3920 
3921 #ifdef SQLITE_ENABLE_API_ARMOR
3922   if( !sqlite3SafetyCheckOk(db) ){
3923     return SQLITE_MISUSE_BKPT;
3924   }
3925 #endif
3926   sqlite3_mutex_enter(db->mutex);
3927 
3928   iDb = sqlite3FindDbName(db, zDb);
3929   if( iDb==0 || iDb>1 ){
3930     Btree *pBt = db->aDb[iDb].pBt;
3931     if( 0==sqlite3BtreeIsInTrans(pBt) ){
3932       rc = sqlite3BtreeBeginTrans(pBt, 0);
3933       if( rc==SQLITE_OK ){
3934         rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
3935       }
3936     }
3937   }
3938 
3939   sqlite3_mutex_leave(db->mutex);
3940 #endif   /* SQLITE_OMIT_WAL */
3941   return rc;
3942 }
3943 
3944 /*
3945 ** Open a read-transaction on the snapshot idendified by pSnapshot.
3946 */
3947 int sqlite3_snapshot_open(
3948   sqlite3 *db,
3949   const char *zDb,
3950   sqlite3_snapshot *pSnapshot
3951 ){
3952   int rc = SQLITE_ERROR;
3953 #ifndef SQLITE_OMIT_WAL
3954 
3955 #ifdef SQLITE_ENABLE_API_ARMOR
3956   if( !sqlite3SafetyCheckOk(db) ){
3957     return SQLITE_MISUSE_BKPT;
3958   }
3959 #endif
3960   sqlite3_mutex_enter(db->mutex);
3961   if( db->autoCommit==0 ){
3962     int iDb;
3963     iDb = sqlite3FindDbName(db, zDb);
3964     if( iDb==0 || iDb>1 ){
3965       Btree *pBt = db->aDb[iDb].pBt;
3966       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
3967         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
3968         if( rc==SQLITE_OK ){
3969           rc = sqlite3BtreeBeginTrans(pBt, 0);
3970           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
3971         }
3972       }
3973     }
3974   }
3975 
3976   sqlite3_mutex_leave(db->mutex);
3977 #endif   /* SQLITE_OMIT_WAL */
3978   return rc;
3979 }
3980 
3981 /*
3982 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
3983 */
3984 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
3985   sqlite3_free(pSnapshot);
3986 }
3987 #endif /* SQLITE_ENABLE_SNAPSHOT */
3988