xref: /sqlite-3.40.0/src/main.c (revision 38c3d3d8)
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     default: {
637       rc = SQLITE_ERROR;
638       break;
639     }
640   }
641   va_end(ap);
642   return rc;
643 }
644 
645 /*
646 ** Set up the lookaside buffers for a database connection.
647 ** Return SQLITE_OK on success.
648 ** If lookaside is already active, return SQLITE_BUSY.
649 **
650 ** The sz parameter is the number of bytes in each lookaside slot.
651 ** The cnt parameter is the number of slots.  If pStart is NULL the
652 ** space for the lookaside memory is obtained from sqlite3_malloc().
653 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
654 ** the lookaside memory.
655 */
656 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
657 #ifndef SQLITE_OMIT_LOOKASIDE
658   void *pStart;
659   if( db->lookaside.nOut ){
660     return SQLITE_BUSY;
661   }
662   /* Free any existing lookaside buffer for this handle before
663   ** allocating a new one so we don't have to have space for
664   ** both at the same time.
665   */
666   if( db->lookaside.bMalloced ){
667     sqlite3_free(db->lookaside.pStart);
668   }
669   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
670   ** than a pointer to be useful.
671   */
672   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
673   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
674   if( cnt<0 ) cnt = 0;
675   if( sz==0 || cnt==0 ){
676     sz = 0;
677     pStart = 0;
678   }else if( pBuf==0 ){
679     sqlite3BeginBenignMalloc();
680     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
681     sqlite3EndBenignMalloc();
682     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
683   }else{
684     pStart = pBuf;
685   }
686   db->lookaside.pStart = pStart;
687   db->lookaside.pFree = 0;
688   db->lookaside.sz = (u16)sz;
689   if( pStart ){
690     int i;
691     LookasideSlot *p;
692     assert( sz > (int)sizeof(LookasideSlot*) );
693     p = (LookasideSlot*)pStart;
694     for(i=cnt-1; i>=0; i--){
695       p->pNext = db->lookaside.pFree;
696       db->lookaside.pFree = p;
697       p = (LookasideSlot*)&((u8*)p)[sz];
698     }
699     db->lookaside.pEnd = p;
700     db->lookaside.bDisable = 0;
701     db->lookaside.bMalloced = pBuf==0 ?1:0;
702   }else{
703     db->lookaside.pStart = db;
704     db->lookaside.pEnd = db;
705     db->lookaside.bDisable = 1;
706     db->lookaside.bMalloced = 0;
707   }
708 #endif /* SQLITE_OMIT_LOOKASIDE */
709   return SQLITE_OK;
710 }
711 
712 /*
713 ** Return the mutex associated with a database connection.
714 */
715 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
716 #ifdef SQLITE_ENABLE_API_ARMOR
717   if( !sqlite3SafetyCheckOk(db) ){
718     (void)SQLITE_MISUSE_BKPT;
719     return 0;
720   }
721 #endif
722   return db->mutex;
723 }
724 
725 /*
726 ** Free up as much memory as we can from the given database
727 ** connection.
728 */
729 int sqlite3_db_release_memory(sqlite3 *db){
730   int i;
731 
732 #ifdef SQLITE_ENABLE_API_ARMOR
733   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
734 #endif
735   sqlite3_mutex_enter(db->mutex);
736   sqlite3BtreeEnterAll(db);
737   for(i=0; i<db->nDb; i++){
738     Btree *pBt = db->aDb[i].pBt;
739     if( pBt ){
740       Pager *pPager = sqlite3BtreePager(pBt);
741       sqlite3PagerShrink(pPager);
742     }
743   }
744   sqlite3BtreeLeaveAll(db);
745   sqlite3_mutex_leave(db->mutex);
746   return SQLITE_OK;
747 }
748 
749 /*
750 ** Flush any dirty pages in the pager-cache for any attached database
751 ** to disk.
752 */
753 int sqlite3_db_cacheflush(sqlite3 *db){
754   int i;
755   int rc = SQLITE_OK;
756   int bSeenBusy = 0;
757 
758 #ifdef SQLITE_ENABLE_API_ARMOR
759   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
760 #endif
761   sqlite3_mutex_enter(db->mutex);
762   sqlite3BtreeEnterAll(db);
763   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
764     Btree *pBt = db->aDb[i].pBt;
765     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
766       Pager *pPager = sqlite3BtreePager(pBt);
767       rc = sqlite3PagerFlush(pPager);
768       if( rc==SQLITE_BUSY ){
769         bSeenBusy = 1;
770         rc = SQLITE_OK;
771       }
772     }
773   }
774   sqlite3BtreeLeaveAll(db);
775   sqlite3_mutex_leave(db->mutex);
776   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
777 }
778 
779 /*
780 ** Configuration settings for an individual database connection
781 */
782 int sqlite3_db_config(sqlite3 *db, int op, ...){
783   va_list ap;
784   int rc;
785   va_start(ap, op);
786   switch( op ){
787     case SQLITE_DBCONFIG_LOOKASIDE: {
788       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
789       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
790       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
791       rc = setupLookaside(db, pBuf, sz, cnt);
792       break;
793     }
794     default: {
795       static const struct {
796         int op;      /* The opcode */
797         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
798       } aFlagOp[] = {
799         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
800         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
801         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
802       };
803       unsigned int i;
804       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
805       for(i=0; i<ArraySize(aFlagOp); i++){
806         if( aFlagOp[i].op==op ){
807           int onoff = va_arg(ap, int);
808           int *pRes = va_arg(ap, int*);
809           int oldFlags = db->flags;
810           if( onoff>0 ){
811             db->flags |= aFlagOp[i].mask;
812           }else if( onoff==0 ){
813             db->flags &= ~aFlagOp[i].mask;
814           }
815           if( oldFlags!=db->flags ){
816             sqlite3ExpirePreparedStatements(db);
817           }
818           if( pRes ){
819             *pRes = (db->flags & aFlagOp[i].mask)!=0;
820           }
821           rc = SQLITE_OK;
822           break;
823         }
824       }
825       break;
826     }
827   }
828   va_end(ap);
829   return rc;
830 }
831 
832 
833 /*
834 ** Return true if the buffer z[0..n-1] contains all spaces.
835 */
836 static int allSpaces(const char *z, int n){
837   while( n>0 && z[n-1]==' ' ){ n--; }
838   return n==0;
839 }
840 
841 /*
842 ** This is the default collating function named "BINARY" which is always
843 ** available.
844 **
845 ** If the padFlag argument is not NULL then space padding at the end
846 ** of strings is ignored.  This implements the RTRIM collation.
847 */
848 static int binCollFunc(
849   void *padFlag,
850   int nKey1, const void *pKey1,
851   int nKey2, const void *pKey2
852 ){
853   int rc, n;
854   n = nKey1<nKey2 ? nKey1 : nKey2;
855   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
856   ** strings byte by byte using the memcmp() function from the standard C
857   ** library. */
858   rc = memcmp(pKey1, pKey2, n);
859   if( rc==0 ){
860     if( padFlag
861      && allSpaces(((char*)pKey1)+n, nKey1-n)
862      && allSpaces(((char*)pKey2)+n, nKey2-n)
863     ){
864       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
865       ** spaces at the end of either string do not change the result. In other
866       ** words, strings will compare equal to one another as long as they
867       ** differ only in the number of spaces at the end.
868       */
869     }else{
870       rc = nKey1 - nKey2;
871     }
872   }
873   return rc;
874 }
875 
876 /*
877 ** Another built-in collating sequence: NOCASE.
878 **
879 ** This collating sequence is intended to be used for "case independent
880 ** comparison". SQLite's knowledge of upper and lower case equivalents
881 ** extends only to the 26 characters used in the English language.
882 **
883 ** At the moment there is only a UTF-8 implementation.
884 */
885 static int nocaseCollatingFunc(
886   void *NotUsed,
887   int nKey1, const void *pKey1,
888   int nKey2, const void *pKey2
889 ){
890   int r = sqlite3StrNICmp(
891       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
892   UNUSED_PARAMETER(NotUsed);
893   if( 0==r ){
894     r = nKey1-nKey2;
895   }
896   return r;
897 }
898 
899 /*
900 ** Return the ROWID of the most recent insert
901 */
902 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
903 #ifdef SQLITE_ENABLE_API_ARMOR
904   if( !sqlite3SafetyCheckOk(db) ){
905     (void)SQLITE_MISUSE_BKPT;
906     return 0;
907   }
908 #endif
909   return db->lastRowid;
910 }
911 
912 /*
913 ** Return the number of changes in the most recent call to sqlite3_exec().
914 */
915 int sqlite3_changes(sqlite3 *db){
916 #ifdef SQLITE_ENABLE_API_ARMOR
917   if( !sqlite3SafetyCheckOk(db) ){
918     (void)SQLITE_MISUSE_BKPT;
919     return 0;
920   }
921 #endif
922   return db->nChange;
923 }
924 
925 /*
926 ** Return the number of changes since the database handle was opened.
927 */
928 int sqlite3_total_changes(sqlite3 *db){
929 #ifdef SQLITE_ENABLE_API_ARMOR
930   if( !sqlite3SafetyCheckOk(db) ){
931     (void)SQLITE_MISUSE_BKPT;
932     return 0;
933   }
934 #endif
935   return db->nTotalChange;
936 }
937 
938 /*
939 ** Close all open savepoints. This function only manipulates fields of the
940 ** database handle object, it does not close any savepoints that may be open
941 ** at the b-tree/pager level.
942 */
943 void sqlite3CloseSavepoints(sqlite3 *db){
944   while( db->pSavepoint ){
945     Savepoint *pTmp = db->pSavepoint;
946     db->pSavepoint = pTmp->pNext;
947     sqlite3DbFree(db, pTmp);
948   }
949   db->nSavepoint = 0;
950   db->nStatement = 0;
951   db->isTransactionSavepoint = 0;
952 }
953 
954 /*
955 ** Invoke the destructor function associated with FuncDef p, if any. Except,
956 ** if this is not the last copy of the function, do not invoke it. Multiple
957 ** copies of a single function are created when create_function() is called
958 ** with SQLITE_ANY as the encoding.
959 */
960 static void functionDestroy(sqlite3 *db, FuncDef *p){
961   FuncDestructor *pDestructor = p->u.pDestructor;
962   if( pDestructor ){
963     pDestructor->nRef--;
964     if( pDestructor->nRef==0 ){
965       pDestructor->xDestroy(pDestructor->pUserData);
966       sqlite3DbFree(db, pDestructor);
967     }
968   }
969 }
970 
971 /*
972 ** Disconnect all sqlite3_vtab objects that belong to database connection
973 ** db. This is called when db is being closed.
974 */
975 static void disconnectAllVtab(sqlite3 *db){
976 #ifndef SQLITE_OMIT_VIRTUALTABLE
977   int i;
978   HashElem *p;
979   sqlite3BtreeEnterAll(db);
980   for(i=0; i<db->nDb; i++){
981     Schema *pSchema = db->aDb[i].pSchema;
982     if( db->aDb[i].pSchema ){
983       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
984         Table *pTab = (Table *)sqliteHashData(p);
985         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
986       }
987     }
988   }
989   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
990     Module *pMod = (Module *)sqliteHashData(p);
991     if( pMod->pEpoTab ){
992       sqlite3VtabDisconnect(db, pMod->pEpoTab);
993     }
994   }
995   sqlite3VtabUnlockList(db);
996   sqlite3BtreeLeaveAll(db);
997 #else
998   UNUSED_PARAMETER(db);
999 #endif
1000 }
1001 
1002 /*
1003 ** Return TRUE if database connection db has unfinalized prepared
1004 ** statements or unfinished sqlite3_backup objects.
1005 */
1006 static int connectionIsBusy(sqlite3 *db){
1007   int j;
1008   assert( sqlite3_mutex_held(db->mutex) );
1009   if( db->pVdbe ) return 1;
1010   for(j=0; j<db->nDb; j++){
1011     Btree *pBt = db->aDb[j].pBt;
1012     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1013   }
1014   return 0;
1015 }
1016 
1017 /*
1018 ** Close an existing SQLite database
1019 */
1020 static int sqlite3Close(sqlite3 *db, int forceZombie){
1021   if( !db ){
1022     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1023     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1024     return SQLITE_OK;
1025   }
1026   if( !sqlite3SafetyCheckSickOrOk(db) ){
1027     return SQLITE_MISUSE_BKPT;
1028   }
1029   sqlite3_mutex_enter(db->mutex);
1030 
1031   /* Force xDisconnect calls on all virtual tables */
1032   disconnectAllVtab(db);
1033 
1034   /* If a transaction is open, the disconnectAllVtab() call above
1035   ** will not have called the xDisconnect() method on any virtual
1036   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1037   ** call will do so. We need to do this before the check for active
1038   ** SQL statements below, as the v-table implementation may be storing
1039   ** some prepared statements internally.
1040   */
1041   sqlite3VtabRollback(db);
1042 
1043   /* Legacy behavior (sqlite3_close() behavior) is to return
1044   ** SQLITE_BUSY if the connection can not be closed immediately.
1045   */
1046   if( !forceZombie && connectionIsBusy(db) ){
1047     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1048        "statements or unfinished backups");
1049     sqlite3_mutex_leave(db->mutex);
1050     return SQLITE_BUSY;
1051   }
1052 
1053 #ifdef SQLITE_ENABLE_SQLLOG
1054   if( sqlite3GlobalConfig.xSqllog ){
1055     /* Closing the handle. Fourth parameter is passed the value 2. */
1056     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1057   }
1058 #endif
1059 
1060   /* Convert the connection into a zombie and then close it.
1061   */
1062   db->magic = SQLITE_MAGIC_ZOMBIE;
1063   sqlite3LeaveMutexAndCloseZombie(db);
1064   return SQLITE_OK;
1065 }
1066 
1067 /*
1068 ** Two variations on the public interface for closing a database
1069 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1070 ** leaves the connection option if there are unfinalized prepared
1071 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1072 ** version forces the connection to become a zombie if there are
1073 ** unclosed resources, and arranges for deallocation when the last
1074 ** prepare statement or sqlite3_backup closes.
1075 */
1076 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1077 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1078 
1079 
1080 /*
1081 ** Close the mutex on database connection db.
1082 **
1083 ** Furthermore, if database connection db is a zombie (meaning that there
1084 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1085 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1086 ** finished, then free all resources.
1087 */
1088 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1089   HashElem *i;                    /* Hash table iterator */
1090   int j;
1091 
1092   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1093   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1094   ** then just leave the mutex and return.
1095   */
1096   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1097     sqlite3_mutex_leave(db->mutex);
1098     return;
1099   }
1100 
1101   /* If we reach this point, it means that the database connection has
1102   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1103   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1104   ** go ahead and free all resources.
1105   */
1106 
1107   /* If a transaction is open, roll it back. This also ensures that if
1108   ** any database schemas have been modified by an uncommitted transaction
1109   ** they are reset. And that the required b-tree mutex is held to make
1110   ** the pager rollback and schema reset an atomic operation. */
1111   sqlite3RollbackAll(db, SQLITE_OK);
1112 
1113   /* Free any outstanding Savepoint structures. */
1114   sqlite3CloseSavepoints(db);
1115 
1116   /* Close all database connections */
1117   for(j=0; j<db->nDb; j++){
1118     struct Db *pDb = &db->aDb[j];
1119     if( pDb->pBt ){
1120       sqlite3BtreeClose(pDb->pBt);
1121       pDb->pBt = 0;
1122       if( j!=1 ){
1123         pDb->pSchema = 0;
1124       }
1125     }
1126   }
1127   /* Clear the TEMP schema separately and last */
1128   if( db->aDb[1].pSchema ){
1129     sqlite3SchemaClear(db->aDb[1].pSchema);
1130   }
1131   sqlite3VtabUnlockList(db);
1132 
1133   /* Free up the array of auxiliary databases */
1134   sqlite3CollapseDatabaseArray(db);
1135   assert( db->nDb<=2 );
1136   assert( db->aDb==db->aDbStatic );
1137 
1138   /* Tell the code in notify.c that the connection no longer holds any
1139   ** locks and does not require any further unlock-notify callbacks.
1140   */
1141   sqlite3ConnectionClosed(db);
1142 
1143   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1144     FuncDef *pNext, *p;
1145     p = sqliteHashData(i);
1146     do{
1147       functionDestroy(db, p);
1148       pNext = p->pNext;
1149       sqlite3DbFree(db, p);
1150       p = pNext;
1151     }while( p );
1152   }
1153   sqlite3HashClear(&db->aFunc);
1154   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1155     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1156     /* Invoke any destructors registered for collation sequence user data. */
1157     for(j=0; j<3; j++){
1158       if( pColl[j].xDel ){
1159         pColl[j].xDel(pColl[j].pUser);
1160       }
1161     }
1162     sqlite3DbFree(db, pColl);
1163   }
1164   sqlite3HashClear(&db->aCollSeq);
1165 #ifndef SQLITE_OMIT_VIRTUALTABLE
1166   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1167     Module *pMod = (Module *)sqliteHashData(i);
1168     if( pMod->xDestroy ){
1169       pMod->xDestroy(pMod->pAux);
1170     }
1171     sqlite3VtabEponymousTableClear(db, pMod);
1172     sqlite3DbFree(db, pMod);
1173   }
1174   sqlite3HashClear(&db->aModule);
1175 #endif
1176 
1177   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1178   sqlite3ValueFree(db->pErr);
1179   sqlite3CloseExtensions(db);
1180 #if SQLITE_USER_AUTHENTICATION
1181   sqlite3_free(db->auth.zAuthUser);
1182   sqlite3_free(db->auth.zAuthPW);
1183 #endif
1184 
1185   db->magic = SQLITE_MAGIC_ERROR;
1186 
1187   /* The temp-database schema is allocated differently from the other schema
1188   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1189   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1190   ** the same sqliteMalloc() as the one that allocates the database
1191   ** structure?
1192   */
1193   sqlite3DbFree(db, db->aDb[1].pSchema);
1194   sqlite3_mutex_leave(db->mutex);
1195   db->magic = SQLITE_MAGIC_CLOSED;
1196   sqlite3_mutex_free(db->mutex);
1197   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1198   if( db->lookaside.bMalloced ){
1199     sqlite3_free(db->lookaside.pStart);
1200   }
1201   sqlite3_free(db);
1202 }
1203 
1204 /*
1205 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1206 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1207 ** breaker") and made to return tripCode if there are any further
1208 ** attempts to use that cursor.  Read cursors remain open and valid
1209 ** but are "saved" in case the table pages are moved around.
1210 */
1211 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1212   int i;
1213   int inTrans = 0;
1214   int schemaChange;
1215   assert( sqlite3_mutex_held(db->mutex) );
1216   sqlite3BeginBenignMalloc();
1217 
1218   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1219   ** This is important in case the transaction being rolled back has
1220   ** modified the database schema. If the b-tree mutexes are not taken
1221   ** here, then another shared-cache connection might sneak in between
1222   ** the database rollback and schema reset, which can cause false
1223   ** corruption reports in some cases.  */
1224   sqlite3BtreeEnterAll(db);
1225   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1226 
1227   for(i=0; i<db->nDb; i++){
1228     Btree *p = db->aDb[i].pBt;
1229     if( p ){
1230       if( sqlite3BtreeIsInTrans(p) ){
1231         inTrans = 1;
1232       }
1233       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1234     }
1235   }
1236   sqlite3VtabRollback(db);
1237   sqlite3EndBenignMalloc();
1238 
1239   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1240     sqlite3ExpirePreparedStatements(db);
1241     sqlite3ResetAllSchemasOfConnection(db);
1242   }
1243   sqlite3BtreeLeaveAll(db);
1244 
1245   /* Any deferred constraint violations have now been resolved. */
1246   db->nDeferredCons = 0;
1247   db->nDeferredImmCons = 0;
1248   db->flags &= ~SQLITE_DeferFKs;
1249 
1250   /* If one has been configured, invoke the rollback-hook callback */
1251   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1252     db->xRollbackCallback(db->pRollbackArg);
1253   }
1254 }
1255 
1256 /*
1257 ** Return a static string containing the name corresponding to the error code
1258 ** specified in the argument.
1259 */
1260 #if defined(SQLITE_NEED_ERR_NAME)
1261 const char *sqlite3ErrName(int rc){
1262   const char *zName = 0;
1263   int i, origRc = rc;
1264   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1265     switch( rc ){
1266       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1267       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1268       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1269       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1270       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1271       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1272       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1273       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1274       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1275       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1276       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1277       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1278       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1279       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1280       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1281       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1282       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1283       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1284       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1285       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1286       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1287       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1288       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1289       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1290       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1291       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1292       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1293       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1294       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1295       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1296       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1297       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1298                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1299       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1300       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1301       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1302       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1303       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1304       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1305       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1306       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1307       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1308       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1309       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1310       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1311       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1312       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1313       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1314       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1315       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1316       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1317       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1318       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1319       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1320       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1321       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1322       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1323       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1324       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1325       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1326       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1327       case SQLITE_CONSTRAINT_FOREIGNKEY:
1328                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1329       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1330       case SQLITE_CONSTRAINT_PRIMARYKEY:
1331                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1332       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1333       case SQLITE_CONSTRAINT_COMMITHOOK:
1334                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1335       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1336       case SQLITE_CONSTRAINT_FUNCTION:
1337                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1338       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1339       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1340       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1341       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1342       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1343       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1344       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1345       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1346       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1347       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1348       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1349       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1350                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1351       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1352       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1353       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1354     }
1355   }
1356   if( zName==0 ){
1357     static char zBuf[50];
1358     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1359     zName = zBuf;
1360   }
1361   return zName;
1362 }
1363 #endif
1364 
1365 /*
1366 ** Return a static string that describes the kind of error specified in the
1367 ** argument.
1368 */
1369 const char *sqlite3ErrStr(int rc){
1370   static const char* const aMsg[] = {
1371     /* SQLITE_OK          */ "not an error",
1372     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1373     /* SQLITE_INTERNAL    */ 0,
1374     /* SQLITE_PERM        */ "access permission denied",
1375     /* SQLITE_ABORT       */ "callback requested query abort",
1376     /* SQLITE_BUSY        */ "database is locked",
1377     /* SQLITE_LOCKED      */ "database table is locked",
1378     /* SQLITE_NOMEM       */ "out of memory",
1379     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1380     /* SQLITE_INTERRUPT   */ "interrupted",
1381     /* SQLITE_IOERR       */ "disk I/O error",
1382     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1383     /* SQLITE_NOTFOUND    */ "unknown operation",
1384     /* SQLITE_FULL        */ "database or disk is full",
1385     /* SQLITE_CANTOPEN    */ "unable to open database file",
1386     /* SQLITE_PROTOCOL    */ "locking protocol",
1387     /* SQLITE_EMPTY       */ "table contains no data",
1388     /* SQLITE_SCHEMA      */ "database schema has changed",
1389     /* SQLITE_TOOBIG      */ "string or blob too big",
1390     /* SQLITE_CONSTRAINT  */ "constraint failed",
1391     /* SQLITE_MISMATCH    */ "datatype mismatch",
1392     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1393     /* SQLITE_NOLFS       */ "large file support is disabled",
1394     /* SQLITE_AUTH        */ "authorization denied",
1395     /* SQLITE_FORMAT      */ "auxiliary database format error",
1396     /* SQLITE_RANGE       */ "bind or column index out of range",
1397     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1398   };
1399   const char *zErr = "unknown error";
1400   switch( rc ){
1401     case SQLITE_ABORT_ROLLBACK: {
1402       zErr = "abort due to ROLLBACK";
1403       break;
1404     }
1405     default: {
1406       rc &= 0xff;
1407       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1408         zErr = aMsg[rc];
1409       }
1410       break;
1411     }
1412   }
1413   return zErr;
1414 }
1415 
1416 /*
1417 ** This routine implements a busy callback that sleeps and tries
1418 ** again until a timeout value is reached.  The timeout value is
1419 ** an integer number of milliseconds passed in as the first
1420 ** argument.
1421 */
1422 static int sqliteDefaultBusyCallback(
1423  void *ptr,               /* Database connection */
1424  int count                /* Number of times table has been busy */
1425 ){
1426 #if SQLITE_OS_WIN || HAVE_USLEEP
1427   static const u8 delays[] =
1428      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1429   static const u8 totals[] =
1430      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1431 # define NDELAY ArraySize(delays)
1432   sqlite3 *db = (sqlite3 *)ptr;
1433   int timeout = db->busyTimeout;
1434   int delay, prior;
1435 
1436   assert( count>=0 );
1437   if( count < NDELAY ){
1438     delay = delays[count];
1439     prior = totals[count];
1440   }else{
1441     delay = delays[NDELAY-1];
1442     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1443   }
1444   if( prior + delay > timeout ){
1445     delay = timeout - prior;
1446     if( delay<=0 ) return 0;
1447   }
1448   sqlite3OsSleep(db->pVfs, delay*1000);
1449   return 1;
1450 #else
1451   sqlite3 *db = (sqlite3 *)ptr;
1452   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1453   if( (count+1)*1000 > timeout ){
1454     return 0;
1455   }
1456   sqlite3OsSleep(db->pVfs, 1000000);
1457   return 1;
1458 #endif
1459 }
1460 
1461 /*
1462 ** Invoke the given busy handler.
1463 **
1464 ** This routine is called when an operation failed with a lock.
1465 ** If this routine returns non-zero, the lock is retried.  If it
1466 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1467 */
1468 int sqlite3InvokeBusyHandler(BusyHandler *p){
1469   int rc;
1470   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1471   rc = p->xFunc(p->pArg, p->nBusy);
1472   if( rc==0 ){
1473     p->nBusy = -1;
1474   }else{
1475     p->nBusy++;
1476   }
1477   return rc;
1478 }
1479 
1480 /*
1481 ** This routine sets the busy callback for an Sqlite database to the
1482 ** given callback function with the given argument.
1483 */
1484 int sqlite3_busy_handler(
1485   sqlite3 *db,
1486   int (*xBusy)(void*,int),
1487   void *pArg
1488 ){
1489 #ifdef SQLITE_ENABLE_API_ARMOR
1490   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1491 #endif
1492   sqlite3_mutex_enter(db->mutex);
1493   db->busyHandler.xFunc = xBusy;
1494   db->busyHandler.pArg = pArg;
1495   db->busyHandler.nBusy = 0;
1496   db->busyTimeout = 0;
1497   sqlite3_mutex_leave(db->mutex);
1498   return SQLITE_OK;
1499 }
1500 
1501 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1502 /*
1503 ** This routine sets the progress callback for an Sqlite database to the
1504 ** given callback function with the given argument. The progress callback will
1505 ** be invoked every nOps opcodes.
1506 */
1507 void sqlite3_progress_handler(
1508   sqlite3 *db,
1509   int nOps,
1510   int (*xProgress)(void*),
1511   void *pArg
1512 ){
1513 #ifdef SQLITE_ENABLE_API_ARMOR
1514   if( !sqlite3SafetyCheckOk(db) ){
1515     (void)SQLITE_MISUSE_BKPT;
1516     return;
1517   }
1518 #endif
1519   sqlite3_mutex_enter(db->mutex);
1520   if( nOps>0 ){
1521     db->xProgress = xProgress;
1522     db->nProgressOps = (unsigned)nOps;
1523     db->pProgressArg = pArg;
1524   }else{
1525     db->xProgress = 0;
1526     db->nProgressOps = 0;
1527     db->pProgressArg = 0;
1528   }
1529   sqlite3_mutex_leave(db->mutex);
1530 }
1531 #endif
1532 
1533 
1534 /*
1535 ** This routine installs a default busy handler that waits for the
1536 ** specified number of milliseconds before returning 0.
1537 */
1538 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1539 #ifdef SQLITE_ENABLE_API_ARMOR
1540   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1541 #endif
1542   if( ms>0 ){
1543     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1544     db->busyTimeout = ms;
1545   }else{
1546     sqlite3_busy_handler(db, 0, 0);
1547   }
1548   return SQLITE_OK;
1549 }
1550 
1551 /*
1552 ** Cause any pending operation to stop at its earliest opportunity.
1553 */
1554 void sqlite3_interrupt(sqlite3 *db){
1555 #ifdef SQLITE_ENABLE_API_ARMOR
1556   if( !sqlite3SafetyCheckOk(db) ){
1557     (void)SQLITE_MISUSE_BKPT;
1558     return;
1559   }
1560 #endif
1561   db->u1.isInterrupted = 1;
1562 }
1563 
1564 
1565 /*
1566 ** This function is exactly the same as sqlite3_create_function(), except
1567 ** that it is designed to be called by internal code. The difference is
1568 ** that if a malloc() fails in sqlite3_create_function(), an error code
1569 ** is returned and the mallocFailed flag cleared.
1570 */
1571 int sqlite3CreateFunc(
1572   sqlite3 *db,
1573   const char *zFunctionName,
1574   int nArg,
1575   int enc,
1576   void *pUserData,
1577   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1578   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1579   void (*xFinal)(sqlite3_context*),
1580   FuncDestructor *pDestructor
1581 ){
1582   FuncDef *p;
1583   int nName;
1584   int extraFlags;
1585 
1586   assert( sqlite3_mutex_held(db->mutex) );
1587   if( zFunctionName==0 ||
1588       (xSFunc && (xFinal || xStep)) ||
1589       (!xSFunc && (xFinal && !xStep)) ||
1590       (!xSFunc && (!xFinal && xStep)) ||
1591       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1592       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1593     return SQLITE_MISUSE_BKPT;
1594   }
1595 
1596   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1597   extraFlags = enc &  SQLITE_DETERMINISTIC;
1598   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1599 
1600 #ifndef SQLITE_OMIT_UTF16
1601   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1602   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1603   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1604   **
1605   ** If SQLITE_ANY is specified, add three versions of the function
1606   ** to the hash table.
1607   */
1608   if( enc==SQLITE_UTF16 ){
1609     enc = SQLITE_UTF16NATIVE;
1610   }else if( enc==SQLITE_ANY ){
1611     int rc;
1612     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1613          pUserData, xSFunc, xStep, xFinal, pDestructor);
1614     if( rc==SQLITE_OK ){
1615       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1616           pUserData, xSFunc, xStep, xFinal, pDestructor);
1617     }
1618     if( rc!=SQLITE_OK ){
1619       return rc;
1620     }
1621     enc = SQLITE_UTF16BE;
1622   }
1623 #else
1624   enc = SQLITE_UTF8;
1625 #endif
1626 
1627   /* Check if an existing function is being overridden or deleted. If so,
1628   ** and there are active VMs, then return SQLITE_BUSY. If a function
1629   ** is being overridden/deleted but there are no active VMs, allow the
1630   ** operation to continue but invalidate all precompiled statements.
1631   */
1632   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1633   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1634     if( db->nVdbeActive ){
1635       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1636         "unable to delete/modify user-function due to active statements");
1637       assert( !db->mallocFailed );
1638       return SQLITE_BUSY;
1639     }else{
1640       sqlite3ExpirePreparedStatements(db);
1641     }
1642   }
1643 
1644   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1645   assert(p || db->mallocFailed);
1646   if( !p ){
1647     return SQLITE_NOMEM_BKPT;
1648   }
1649 
1650   /* If an older version of the function with a configured destructor is
1651   ** being replaced invoke the destructor function here. */
1652   functionDestroy(db, p);
1653 
1654   if( pDestructor ){
1655     pDestructor->nRef++;
1656   }
1657   p->u.pDestructor = pDestructor;
1658   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1659   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1660   p->xSFunc = xSFunc ? xSFunc : xStep;
1661   p->xFinalize = xFinal;
1662   p->pUserData = pUserData;
1663   p->nArg = (u16)nArg;
1664   return SQLITE_OK;
1665 }
1666 
1667 /*
1668 ** Create new user functions.
1669 */
1670 int sqlite3_create_function(
1671   sqlite3 *db,
1672   const char *zFunc,
1673   int nArg,
1674   int enc,
1675   void *p,
1676   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1677   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1678   void (*xFinal)(sqlite3_context*)
1679 ){
1680   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1681                                     xFinal, 0);
1682 }
1683 
1684 int sqlite3_create_function_v2(
1685   sqlite3 *db,
1686   const char *zFunc,
1687   int nArg,
1688   int enc,
1689   void *p,
1690   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1691   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1692   void (*xFinal)(sqlite3_context*),
1693   void (*xDestroy)(void *)
1694 ){
1695   int rc = SQLITE_ERROR;
1696   FuncDestructor *pArg = 0;
1697 
1698 #ifdef SQLITE_ENABLE_API_ARMOR
1699   if( !sqlite3SafetyCheckOk(db) ){
1700     return SQLITE_MISUSE_BKPT;
1701   }
1702 #endif
1703   sqlite3_mutex_enter(db->mutex);
1704   if( xDestroy ){
1705     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1706     if( !pArg ){
1707       xDestroy(p);
1708       goto out;
1709     }
1710     pArg->xDestroy = xDestroy;
1711     pArg->pUserData = p;
1712   }
1713   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1714   if( pArg && pArg->nRef==0 ){
1715     assert( rc!=SQLITE_OK );
1716     xDestroy(p);
1717     sqlite3DbFree(db, pArg);
1718   }
1719 
1720  out:
1721   rc = sqlite3ApiExit(db, rc);
1722   sqlite3_mutex_leave(db->mutex);
1723   return rc;
1724 }
1725 
1726 #ifndef SQLITE_OMIT_UTF16
1727 int sqlite3_create_function16(
1728   sqlite3 *db,
1729   const void *zFunctionName,
1730   int nArg,
1731   int eTextRep,
1732   void *p,
1733   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1734   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1735   void (*xFinal)(sqlite3_context*)
1736 ){
1737   int rc;
1738   char *zFunc8;
1739 
1740 #ifdef SQLITE_ENABLE_API_ARMOR
1741   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1742 #endif
1743   sqlite3_mutex_enter(db->mutex);
1744   assert( !db->mallocFailed );
1745   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1746   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1747   sqlite3DbFree(db, zFunc8);
1748   rc = sqlite3ApiExit(db, rc);
1749   sqlite3_mutex_leave(db->mutex);
1750   return rc;
1751 }
1752 #endif
1753 
1754 
1755 /*
1756 ** Declare that a function has been overloaded by a virtual table.
1757 **
1758 ** If the function already exists as a regular global function, then
1759 ** this routine is a no-op.  If the function does not exist, then create
1760 ** a new one that always throws a run-time error.
1761 **
1762 ** When virtual tables intend to provide an overloaded function, they
1763 ** should call this routine to make sure the global function exists.
1764 ** A global function must exist in order for name resolution to work
1765 ** properly.
1766 */
1767 int sqlite3_overload_function(
1768   sqlite3 *db,
1769   const char *zName,
1770   int nArg
1771 ){
1772   int rc = SQLITE_OK;
1773 
1774 #ifdef SQLITE_ENABLE_API_ARMOR
1775   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1776     return SQLITE_MISUSE_BKPT;
1777   }
1778 #endif
1779   sqlite3_mutex_enter(db->mutex);
1780   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1781     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1782                            0, sqlite3InvalidFunction, 0, 0, 0);
1783   }
1784   rc = sqlite3ApiExit(db, rc);
1785   sqlite3_mutex_leave(db->mutex);
1786   return rc;
1787 }
1788 
1789 #ifndef SQLITE_OMIT_TRACE
1790 /*
1791 ** Register a trace function.  The pArg from the previously registered trace
1792 ** is returned.
1793 **
1794 ** A NULL trace function means that no tracing is executes.  A non-NULL
1795 ** trace is a pointer to a function that is invoked at the start of each
1796 ** SQL statement.
1797 */
1798 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1799   void *pOld;
1800 
1801 #ifdef SQLITE_ENABLE_API_ARMOR
1802   if( !sqlite3SafetyCheckOk(db) ){
1803     (void)SQLITE_MISUSE_BKPT;
1804     return 0;
1805   }
1806 #endif
1807   sqlite3_mutex_enter(db->mutex);
1808   pOld = db->pTraceArg;
1809   db->xTrace = xTrace;
1810   db->pTraceArg = pArg;
1811   sqlite3_mutex_leave(db->mutex);
1812   return pOld;
1813 }
1814 /*
1815 ** Register a profile function.  The pArg from the previously registered
1816 ** profile function is returned.
1817 **
1818 ** A NULL profile function means that no profiling is executes.  A non-NULL
1819 ** profile is a pointer to a function that is invoked at the conclusion of
1820 ** each SQL statement that is run.
1821 */
1822 void *sqlite3_profile(
1823   sqlite3 *db,
1824   void (*xProfile)(void*,const char*,sqlite_uint64),
1825   void *pArg
1826 ){
1827   void *pOld;
1828 
1829 #ifdef SQLITE_ENABLE_API_ARMOR
1830   if( !sqlite3SafetyCheckOk(db) ){
1831     (void)SQLITE_MISUSE_BKPT;
1832     return 0;
1833   }
1834 #endif
1835   sqlite3_mutex_enter(db->mutex);
1836   pOld = db->pProfileArg;
1837   db->xProfile = xProfile;
1838   db->pProfileArg = pArg;
1839   sqlite3_mutex_leave(db->mutex);
1840   return pOld;
1841 }
1842 #endif /* SQLITE_OMIT_TRACE */
1843 
1844 /*
1845 ** Register a function to be invoked when a transaction commits.
1846 ** If the invoked function returns non-zero, then the commit becomes a
1847 ** rollback.
1848 */
1849 void *sqlite3_commit_hook(
1850   sqlite3 *db,              /* Attach the hook to this database */
1851   int (*xCallback)(void*),  /* Function to invoke on each commit */
1852   void *pArg                /* Argument to the function */
1853 ){
1854   void *pOld;
1855 
1856 #ifdef SQLITE_ENABLE_API_ARMOR
1857   if( !sqlite3SafetyCheckOk(db) ){
1858     (void)SQLITE_MISUSE_BKPT;
1859     return 0;
1860   }
1861 #endif
1862   sqlite3_mutex_enter(db->mutex);
1863   pOld = db->pCommitArg;
1864   db->xCommitCallback = xCallback;
1865   db->pCommitArg = pArg;
1866   sqlite3_mutex_leave(db->mutex);
1867   return pOld;
1868 }
1869 
1870 /*
1871 ** Register a callback to be invoked each time a row is updated,
1872 ** inserted or deleted using this database connection.
1873 */
1874 void *sqlite3_update_hook(
1875   sqlite3 *db,              /* Attach the hook to this database */
1876   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1877   void *pArg                /* Argument to the function */
1878 ){
1879   void *pRet;
1880 
1881 #ifdef SQLITE_ENABLE_API_ARMOR
1882   if( !sqlite3SafetyCheckOk(db) ){
1883     (void)SQLITE_MISUSE_BKPT;
1884     return 0;
1885   }
1886 #endif
1887   sqlite3_mutex_enter(db->mutex);
1888   pRet = db->pUpdateArg;
1889   db->xUpdateCallback = xCallback;
1890   db->pUpdateArg = pArg;
1891   sqlite3_mutex_leave(db->mutex);
1892   return pRet;
1893 }
1894 
1895 /*
1896 ** Register a callback to be invoked each time a transaction is rolled
1897 ** back by this database connection.
1898 */
1899 void *sqlite3_rollback_hook(
1900   sqlite3 *db,              /* Attach the hook to this database */
1901   void (*xCallback)(void*), /* Callback function */
1902   void *pArg                /* Argument to the function */
1903 ){
1904   void *pRet;
1905 
1906 #ifdef SQLITE_ENABLE_API_ARMOR
1907   if( !sqlite3SafetyCheckOk(db) ){
1908     (void)SQLITE_MISUSE_BKPT;
1909     return 0;
1910   }
1911 #endif
1912   sqlite3_mutex_enter(db->mutex);
1913   pRet = db->pRollbackArg;
1914   db->xRollbackCallback = xCallback;
1915   db->pRollbackArg = pArg;
1916   sqlite3_mutex_leave(db->mutex);
1917   return pRet;
1918 }
1919 
1920 #ifndef SQLITE_OMIT_WAL
1921 /*
1922 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1923 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1924 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1925 ** wal_autocheckpoint()).
1926 */
1927 int sqlite3WalDefaultHook(
1928   void *pClientData,     /* Argument */
1929   sqlite3 *db,           /* Connection */
1930   const char *zDb,       /* Database */
1931   int nFrame             /* Size of WAL */
1932 ){
1933   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1934     sqlite3BeginBenignMalloc();
1935     sqlite3_wal_checkpoint(db, zDb);
1936     sqlite3EndBenignMalloc();
1937   }
1938   return SQLITE_OK;
1939 }
1940 #endif /* SQLITE_OMIT_WAL */
1941 
1942 /*
1943 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1944 ** a database after committing a transaction if there are nFrame or
1945 ** more frames in the log file. Passing zero or a negative value as the
1946 ** nFrame parameter disables automatic checkpoints entirely.
1947 **
1948 ** The callback registered by this function replaces any existing callback
1949 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1950 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1951 ** configured by this function.
1952 */
1953 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1954 #ifdef SQLITE_OMIT_WAL
1955   UNUSED_PARAMETER(db);
1956   UNUSED_PARAMETER(nFrame);
1957 #else
1958 #ifdef SQLITE_ENABLE_API_ARMOR
1959   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1960 #endif
1961   if( nFrame>0 ){
1962     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1963   }else{
1964     sqlite3_wal_hook(db, 0, 0);
1965   }
1966 #endif
1967   return SQLITE_OK;
1968 }
1969 
1970 /*
1971 ** Register a callback to be invoked each time a transaction is written
1972 ** into the write-ahead-log by this database connection.
1973 */
1974 void *sqlite3_wal_hook(
1975   sqlite3 *db,                    /* Attach the hook to this db handle */
1976   int(*xCallback)(void *, sqlite3*, const char*, int),
1977   void *pArg                      /* First argument passed to xCallback() */
1978 ){
1979 #ifndef SQLITE_OMIT_WAL
1980   void *pRet;
1981 #ifdef SQLITE_ENABLE_API_ARMOR
1982   if( !sqlite3SafetyCheckOk(db) ){
1983     (void)SQLITE_MISUSE_BKPT;
1984     return 0;
1985   }
1986 #endif
1987   sqlite3_mutex_enter(db->mutex);
1988   pRet = db->pWalArg;
1989   db->xWalCallback = xCallback;
1990   db->pWalArg = pArg;
1991   sqlite3_mutex_leave(db->mutex);
1992   return pRet;
1993 #else
1994   return 0;
1995 #endif
1996 }
1997 
1998 /*
1999 ** Checkpoint database zDb.
2000 */
2001 int sqlite3_wal_checkpoint_v2(
2002   sqlite3 *db,                    /* Database handle */
2003   const char *zDb,                /* Name of attached database (or NULL) */
2004   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2005   int *pnLog,                     /* OUT: Size of WAL log in frames */
2006   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2007 ){
2008 #ifdef SQLITE_OMIT_WAL
2009   return SQLITE_OK;
2010 #else
2011   int rc;                         /* Return code */
2012   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2013 
2014 #ifdef SQLITE_ENABLE_API_ARMOR
2015   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2016 #endif
2017 
2018   /* Initialize the output variables to -1 in case an error occurs. */
2019   if( pnLog ) *pnLog = -1;
2020   if( pnCkpt ) *pnCkpt = -1;
2021 
2022   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2023   assert( SQLITE_CHECKPOINT_FULL==1 );
2024   assert( SQLITE_CHECKPOINT_RESTART==2 );
2025   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2026   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2027     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2028     ** mode: */
2029     return SQLITE_MISUSE;
2030   }
2031 
2032   sqlite3_mutex_enter(db->mutex);
2033   if( zDb && zDb[0] ){
2034     iDb = sqlite3FindDbName(db, zDb);
2035   }
2036   if( iDb<0 ){
2037     rc = SQLITE_ERROR;
2038     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2039   }else{
2040     db->busyHandler.nBusy = 0;
2041     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2042     sqlite3Error(db, rc);
2043   }
2044   rc = sqlite3ApiExit(db, rc);
2045   sqlite3_mutex_leave(db->mutex);
2046   return rc;
2047 #endif
2048 }
2049 
2050 
2051 /*
2052 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2053 ** to contains a zero-length string, all attached databases are
2054 ** checkpointed.
2055 */
2056 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2057   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2058   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2059   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2060 }
2061 
2062 #ifndef SQLITE_OMIT_WAL
2063 /*
2064 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2065 ** not currently open in WAL mode.
2066 **
2067 ** If a transaction is open on the database being checkpointed, this
2068 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2069 ** an error occurs while running the checkpoint, an SQLite error code is
2070 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2071 **
2072 ** The mutex on database handle db should be held by the caller. The mutex
2073 ** associated with the specific b-tree being checkpointed is taken by
2074 ** this function while the checkpoint is running.
2075 **
2076 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2077 ** checkpointed. If an error is encountered it is returned immediately -
2078 ** no attempt is made to checkpoint any remaining databases.
2079 **
2080 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2081 */
2082 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2083   int rc = SQLITE_OK;             /* Return code */
2084   int i;                          /* Used to iterate through attached dbs */
2085   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2086 
2087   assert( sqlite3_mutex_held(db->mutex) );
2088   assert( !pnLog || *pnLog==-1 );
2089   assert( !pnCkpt || *pnCkpt==-1 );
2090 
2091   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2092     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2093       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2094       pnLog = 0;
2095       pnCkpt = 0;
2096       if( rc==SQLITE_BUSY ){
2097         bBusy = 1;
2098         rc = SQLITE_OK;
2099       }
2100     }
2101   }
2102 
2103   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2104 }
2105 #endif /* SQLITE_OMIT_WAL */
2106 
2107 /*
2108 ** This function returns true if main-memory should be used instead of
2109 ** a temporary file for transient pager files and statement journals.
2110 ** The value returned depends on the value of db->temp_store (runtime
2111 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2112 ** following table describes the relationship between these two values
2113 ** and this functions return value.
2114 **
2115 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2116 **   -----------------     --------------     ------------------------------
2117 **   0                     any                file      (return 0)
2118 **   1                     1                  file      (return 0)
2119 **   1                     2                  memory    (return 1)
2120 **   1                     0                  file      (return 0)
2121 **   2                     1                  file      (return 0)
2122 **   2                     2                  memory    (return 1)
2123 **   2                     0                  memory    (return 1)
2124 **   3                     any                memory    (return 1)
2125 */
2126 int sqlite3TempInMemory(const sqlite3 *db){
2127 #if SQLITE_TEMP_STORE==1
2128   return ( db->temp_store==2 );
2129 #endif
2130 #if SQLITE_TEMP_STORE==2
2131   return ( db->temp_store!=1 );
2132 #endif
2133 #if SQLITE_TEMP_STORE==3
2134   UNUSED_PARAMETER(db);
2135   return 1;
2136 #endif
2137 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2138   UNUSED_PARAMETER(db);
2139   return 0;
2140 #endif
2141 }
2142 
2143 /*
2144 ** Return UTF-8 encoded English language explanation of the most recent
2145 ** error.
2146 */
2147 const char *sqlite3_errmsg(sqlite3 *db){
2148   const char *z;
2149   if( !db ){
2150     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2151   }
2152   if( !sqlite3SafetyCheckSickOrOk(db) ){
2153     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2154   }
2155   sqlite3_mutex_enter(db->mutex);
2156   if( db->mallocFailed ){
2157     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2158   }else{
2159     testcase( db->pErr==0 );
2160     z = (char*)sqlite3_value_text(db->pErr);
2161     assert( !db->mallocFailed );
2162     if( z==0 ){
2163       z = sqlite3ErrStr(db->errCode);
2164     }
2165   }
2166   sqlite3_mutex_leave(db->mutex);
2167   return z;
2168 }
2169 
2170 #ifndef SQLITE_OMIT_UTF16
2171 /*
2172 ** Return UTF-16 encoded English language explanation of the most recent
2173 ** error.
2174 */
2175 const void *sqlite3_errmsg16(sqlite3 *db){
2176   static const u16 outOfMem[] = {
2177     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2178   };
2179   static const u16 misuse[] = {
2180     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2181     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2182     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2183     'o', 'u', 't', ' ',
2184     'o', 'f', ' ',
2185     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2186   };
2187 
2188   const void *z;
2189   if( !db ){
2190     return (void *)outOfMem;
2191   }
2192   if( !sqlite3SafetyCheckSickOrOk(db) ){
2193     return (void *)misuse;
2194   }
2195   sqlite3_mutex_enter(db->mutex);
2196   if( db->mallocFailed ){
2197     z = (void *)outOfMem;
2198   }else{
2199     z = sqlite3_value_text16(db->pErr);
2200     if( z==0 ){
2201       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2202       z = sqlite3_value_text16(db->pErr);
2203     }
2204     /* A malloc() may have failed within the call to sqlite3_value_text16()
2205     ** above. If this is the case, then the db->mallocFailed flag needs to
2206     ** be cleared before returning. Do this directly, instead of via
2207     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2208     */
2209     sqlite3OomClear(db);
2210   }
2211   sqlite3_mutex_leave(db->mutex);
2212   return z;
2213 }
2214 #endif /* SQLITE_OMIT_UTF16 */
2215 
2216 /*
2217 ** Return the most recent error code generated by an SQLite routine. If NULL is
2218 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2219 */
2220 int sqlite3_errcode(sqlite3 *db){
2221   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2222     return SQLITE_MISUSE_BKPT;
2223   }
2224   if( !db || db->mallocFailed ){
2225     return SQLITE_NOMEM_BKPT;
2226   }
2227   return db->errCode & db->errMask;
2228 }
2229 int sqlite3_extended_errcode(sqlite3 *db){
2230   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2231     return SQLITE_MISUSE_BKPT;
2232   }
2233   if( !db || db->mallocFailed ){
2234     return SQLITE_NOMEM_BKPT;
2235   }
2236   return db->errCode;
2237 }
2238 
2239 /*
2240 ** Return a string that describes the kind of error specified in the
2241 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2242 ** function.
2243 */
2244 const char *sqlite3_errstr(int rc){
2245   return sqlite3ErrStr(rc);
2246 }
2247 
2248 /*
2249 ** Create a new collating function for database "db".  The name is zName
2250 ** and the encoding is enc.
2251 */
2252 static int createCollation(
2253   sqlite3* db,
2254   const char *zName,
2255   u8 enc,
2256   void* pCtx,
2257   int(*xCompare)(void*,int,const void*,int,const void*),
2258   void(*xDel)(void*)
2259 ){
2260   CollSeq *pColl;
2261   int enc2;
2262 
2263   assert( sqlite3_mutex_held(db->mutex) );
2264 
2265   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2266   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2267   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2268   */
2269   enc2 = enc;
2270   testcase( enc2==SQLITE_UTF16 );
2271   testcase( enc2==SQLITE_UTF16_ALIGNED );
2272   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2273     enc2 = SQLITE_UTF16NATIVE;
2274   }
2275   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2276     return SQLITE_MISUSE_BKPT;
2277   }
2278 
2279   /* Check if this call is removing or replacing an existing collation
2280   ** sequence. If so, and there are active VMs, return busy. If there
2281   ** are no active VMs, invalidate any pre-compiled statements.
2282   */
2283   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2284   if( pColl && pColl->xCmp ){
2285     if( db->nVdbeActive ){
2286       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2287         "unable to delete/modify collation sequence due to active statements");
2288       return SQLITE_BUSY;
2289     }
2290     sqlite3ExpirePreparedStatements(db);
2291 
2292     /* If collation sequence pColl was created directly by a call to
2293     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2294     ** then any copies made by synthCollSeq() need to be invalidated.
2295     ** Also, collation destructor - CollSeq.xDel() - function may need
2296     ** to be called.
2297     */
2298     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2299       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2300       int j;
2301       for(j=0; j<3; j++){
2302         CollSeq *p = &aColl[j];
2303         if( p->enc==pColl->enc ){
2304           if( p->xDel ){
2305             p->xDel(p->pUser);
2306           }
2307           p->xCmp = 0;
2308         }
2309       }
2310     }
2311   }
2312 
2313   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2314   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2315   pColl->xCmp = xCompare;
2316   pColl->pUser = pCtx;
2317   pColl->xDel = xDel;
2318   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2319   sqlite3Error(db, SQLITE_OK);
2320   return SQLITE_OK;
2321 }
2322 
2323 
2324 /*
2325 ** This array defines hard upper bounds on limit values.  The
2326 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2327 ** #defines in sqlite3.h.
2328 */
2329 static const int aHardLimit[] = {
2330   SQLITE_MAX_LENGTH,
2331   SQLITE_MAX_SQL_LENGTH,
2332   SQLITE_MAX_COLUMN,
2333   SQLITE_MAX_EXPR_DEPTH,
2334   SQLITE_MAX_COMPOUND_SELECT,
2335   SQLITE_MAX_VDBE_OP,
2336   SQLITE_MAX_FUNCTION_ARG,
2337   SQLITE_MAX_ATTACHED,
2338   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2339   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2340   SQLITE_MAX_TRIGGER_DEPTH,
2341   SQLITE_MAX_WORKER_THREADS,
2342 };
2343 
2344 /*
2345 ** Make sure the hard limits are set to reasonable values
2346 */
2347 #if SQLITE_MAX_LENGTH<100
2348 # error SQLITE_MAX_LENGTH must be at least 100
2349 #endif
2350 #if SQLITE_MAX_SQL_LENGTH<100
2351 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2352 #endif
2353 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2354 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2355 #endif
2356 #if SQLITE_MAX_COMPOUND_SELECT<2
2357 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2358 #endif
2359 #if SQLITE_MAX_VDBE_OP<40
2360 # error SQLITE_MAX_VDBE_OP must be at least 40
2361 #endif
2362 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2363 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2364 #endif
2365 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2366 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2367 #endif
2368 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2369 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2370 #endif
2371 #if SQLITE_MAX_COLUMN>32767
2372 # error SQLITE_MAX_COLUMN must not exceed 32767
2373 #endif
2374 #if SQLITE_MAX_TRIGGER_DEPTH<1
2375 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2376 #endif
2377 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2378 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2379 #endif
2380 
2381 
2382 /*
2383 ** Change the value of a limit.  Report the old value.
2384 ** If an invalid limit index is supplied, report -1.
2385 ** Make no changes but still report the old value if the
2386 ** new limit is negative.
2387 **
2388 ** A new lower limit does not shrink existing constructs.
2389 ** It merely prevents new constructs that exceed the limit
2390 ** from forming.
2391 */
2392 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2393   int oldLimit;
2394 
2395 #ifdef SQLITE_ENABLE_API_ARMOR
2396   if( !sqlite3SafetyCheckOk(db) ){
2397     (void)SQLITE_MISUSE_BKPT;
2398     return -1;
2399   }
2400 #endif
2401 
2402   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2403   ** there is a hard upper bound set at compile-time by a C preprocessor
2404   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2405   ** "_MAX_".)
2406   */
2407   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2408   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2409   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2410   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2411   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2412   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2413   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2414   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2415   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2416                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2417   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2418   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2419   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2420   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2421 
2422 
2423   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2424     return -1;
2425   }
2426   oldLimit = db->aLimit[limitId];
2427   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2428     if( newLimit>aHardLimit[limitId] ){
2429       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2430     }
2431     db->aLimit[limitId] = newLimit;
2432   }
2433   return oldLimit;                     /* IMP: R-53341-35419 */
2434 }
2435 
2436 /*
2437 ** This function is used to parse both URIs and non-URI filenames passed by the
2438 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2439 ** URIs specified as part of ATTACH statements.
2440 **
2441 ** The first argument to this function is the name of the VFS to use (or
2442 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2443 ** query parameter. The second argument contains the URI (or non-URI filename)
2444 ** itself. When this function is called the *pFlags variable should contain
2445 ** the default flags to open the database handle with. The value stored in
2446 ** *pFlags may be updated before returning if the URI filename contains
2447 ** "cache=xxx" or "mode=xxx" query parameters.
2448 **
2449 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2450 ** the VFS that should be used to open the database file. *pzFile is set to
2451 ** point to a buffer containing the name of the file to open. It is the
2452 ** responsibility of the caller to eventually call sqlite3_free() to release
2453 ** this buffer.
2454 **
2455 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2456 ** may be set to point to a buffer containing an English language error
2457 ** message. It is the responsibility of the caller to eventually release
2458 ** this buffer by calling sqlite3_free().
2459 */
2460 int sqlite3ParseUri(
2461   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2462   const char *zUri,               /* Nul-terminated URI to parse */
2463   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2464   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2465   char **pzFile,                  /* OUT: Filename component of URI */
2466   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2467 ){
2468   int rc = SQLITE_OK;
2469   unsigned int flags = *pFlags;
2470   const char *zVfs = zDefaultVfs;
2471   char *zFile;
2472   char c;
2473   int nUri = sqlite3Strlen30(zUri);
2474 
2475   assert( *pzErrMsg==0 );
2476 
2477   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2478             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2479    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2480   ){
2481     char *zOpt;
2482     int eState;                   /* Parser state when parsing URI */
2483     int iIn;                      /* Input character index */
2484     int iOut = 0;                 /* Output character index */
2485     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2486 
2487     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2488     ** method that there may be extra parameters following the file-name.  */
2489     flags |= SQLITE_OPEN_URI;
2490 
2491     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2492     zFile = sqlite3_malloc64(nByte);
2493     if( !zFile ) return SQLITE_NOMEM_BKPT;
2494 
2495     iIn = 5;
2496 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2497     if( strncmp(zUri+5, "///", 3)==0 ){
2498       iIn = 7;
2499       /* The following condition causes URIs with five leading / characters
2500       ** like file://///host/path to be converted into UNCs like //host/path.
2501       ** The correct URI for that UNC has only two or four leading / characters
2502       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2503       ** common error, we are told, so we handle it as a special case. */
2504       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2505     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2506       iIn = 16;
2507     }
2508 #else
2509     /* Discard the scheme and authority segments of the URI. */
2510     if( zUri[5]=='/' && zUri[6]=='/' ){
2511       iIn = 7;
2512       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2513       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2514         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2515             iIn-7, &zUri[7]);
2516         rc = SQLITE_ERROR;
2517         goto parse_uri_out;
2518       }
2519     }
2520 #endif
2521 
2522     /* Copy the filename and any query parameters into the zFile buffer.
2523     ** Decode %HH escape codes along the way.
2524     **
2525     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2526     ** on the parsing context. As follows:
2527     **
2528     **   0: Parsing file-name.
2529     **   1: Parsing name section of a name=value query parameter.
2530     **   2: Parsing value section of a name=value query parameter.
2531     */
2532     eState = 0;
2533     while( (c = zUri[iIn])!=0 && c!='#' ){
2534       iIn++;
2535       if( c=='%'
2536        && sqlite3Isxdigit(zUri[iIn])
2537        && sqlite3Isxdigit(zUri[iIn+1])
2538       ){
2539         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2540         octet += sqlite3HexToInt(zUri[iIn++]);
2541 
2542         assert( octet>=0 && octet<256 );
2543         if( octet==0 ){
2544           /* This branch is taken when "%00" appears within the URI. In this
2545           ** case we ignore all text in the remainder of the path, name or
2546           ** value currently being parsed. So ignore the current character
2547           ** and skip to the next "?", "=" or "&", as appropriate. */
2548           while( (c = zUri[iIn])!=0 && c!='#'
2549               && (eState!=0 || c!='?')
2550               && (eState!=1 || (c!='=' && c!='&'))
2551               && (eState!=2 || c!='&')
2552           ){
2553             iIn++;
2554           }
2555           continue;
2556         }
2557         c = octet;
2558       }else if( eState==1 && (c=='&' || c=='=') ){
2559         if( zFile[iOut-1]==0 ){
2560           /* An empty option name. Ignore this option altogether. */
2561           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2562           continue;
2563         }
2564         if( c=='&' ){
2565           zFile[iOut++] = '\0';
2566         }else{
2567           eState = 2;
2568         }
2569         c = 0;
2570       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2571         c = 0;
2572         eState = 1;
2573       }
2574       zFile[iOut++] = c;
2575     }
2576     if( eState==1 ) zFile[iOut++] = '\0';
2577     zFile[iOut++] = '\0';
2578     zFile[iOut++] = '\0';
2579 
2580     /* Check if there were any options specified that should be interpreted
2581     ** here. Options that are interpreted here include "vfs" and those that
2582     ** correspond to flags that may be passed to the sqlite3_open_v2()
2583     ** method. */
2584     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2585     while( zOpt[0] ){
2586       int nOpt = sqlite3Strlen30(zOpt);
2587       char *zVal = &zOpt[nOpt+1];
2588       int nVal = sqlite3Strlen30(zVal);
2589 
2590       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2591         zVfs = zVal;
2592       }else{
2593         struct OpenMode {
2594           const char *z;
2595           int mode;
2596         } *aMode = 0;
2597         char *zModeType = 0;
2598         int mask = 0;
2599         int limit = 0;
2600 
2601         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2602           static struct OpenMode aCacheMode[] = {
2603             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2604             { "private", SQLITE_OPEN_PRIVATECACHE },
2605             { 0, 0 }
2606           };
2607 
2608           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2609           aMode = aCacheMode;
2610           limit = mask;
2611           zModeType = "cache";
2612         }
2613         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2614           static struct OpenMode aOpenMode[] = {
2615             { "ro",  SQLITE_OPEN_READONLY },
2616             { "rw",  SQLITE_OPEN_READWRITE },
2617             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2618             { "memory", SQLITE_OPEN_MEMORY },
2619             { 0, 0 }
2620           };
2621 
2622           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2623                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2624           aMode = aOpenMode;
2625           limit = mask & flags;
2626           zModeType = "access";
2627         }
2628 
2629         if( aMode ){
2630           int i;
2631           int mode = 0;
2632           for(i=0; aMode[i].z; i++){
2633             const char *z = aMode[i].z;
2634             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2635               mode = aMode[i].mode;
2636               break;
2637             }
2638           }
2639           if( mode==0 ){
2640             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2641             rc = SQLITE_ERROR;
2642             goto parse_uri_out;
2643           }
2644           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2645             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2646                                         zModeType, zVal);
2647             rc = SQLITE_PERM;
2648             goto parse_uri_out;
2649           }
2650           flags = (flags & ~mask) | mode;
2651         }
2652       }
2653 
2654       zOpt = &zVal[nVal+1];
2655     }
2656 
2657   }else{
2658     zFile = sqlite3_malloc64(nUri+2);
2659     if( !zFile ) return SQLITE_NOMEM_BKPT;
2660     memcpy(zFile, zUri, nUri);
2661     zFile[nUri] = '\0';
2662     zFile[nUri+1] = '\0';
2663     flags &= ~SQLITE_OPEN_URI;
2664   }
2665 
2666   *ppVfs = sqlite3_vfs_find(zVfs);
2667   if( *ppVfs==0 ){
2668     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2669     rc = SQLITE_ERROR;
2670   }
2671  parse_uri_out:
2672   if( rc!=SQLITE_OK ){
2673     sqlite3_free(zFile);
2674     zFile = 0;
2675   }
2676   *pFlags = flags;
2677   *pzFile = zFile;
2678   return rc;
2679 }
2680 
2681 
2682 /*
2683 ** This routine does the work of opening a database on behalf of
2684 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2685 ** is UTF-8 encoded.
2686 */
2687 static int openDatabase(
2688   const char *zFilename, /* Database filename UTF-8 encoded */
2689   sqlite3 **ppDb,        /* OUT: Returned database handle */
2690   unsigned int flags,    /* Operational flags */
2691   const char *zVfs       /* Name of the VFS to use */
2692 ){
2693   sqlite3 *db;                    /* Store allocated handle here */
2694   int rc;                         /* Return code */
2695   int isThreadsafe;               /* True for threadsafe connections */
2696   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2697   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2698 
2699 #ifdef SQLITE_ENABLE_API_ARMOR
2700   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2701 #endif
2702   *ppDb = 0;
2703 #ifndef SQLITE_OMIT_AUTOINIT
2704   rc = sqlite3_initialize();
2705   if( rc ) return rc;
2706 #endif
2707 
2708   /* Only allow sensible combinations of bits in the flags argument.
2709   ** Throw an error if any non-sense combination is used.  If we
2710   ** do not block illegal combinations here, it could trigger
2711   ** assert() statements in deeper layers.  Sensible combinations
2712   ** are:
2713   **
2714   **  1:  SQLITE_OPEN_READONLY
2715   **  2:  SQLITE_OPEN_READWRITE
2716   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2717   */
2718   assert( SQLITE_OPEN_READONLY  == 0x01 );
2719   assert( SQLITE_OPEN_READWRITE == 0x02 );
2720   assert( SQLITE_OPEN_CREATE    == 0x04 );
2721   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2722   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2723   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2724   if( ((1<<(flags&7)) & 0x46)==0 ){
2725     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2726   }
2727 
2728   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2729     isThreadsafe = 0;
2730   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2731     isThreadsafe = 0;
2732   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2733     isThreadsafe = 1;
2734   }else{
2735     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2736   }
2737   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2738     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2739   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2740     flags |= SQLITE_OPEN_SHAREDCACHE;
2741   }
2742 
2743   /* Remove harmful bits from the flags parameter
2744   **
2745   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2746   ** dealt with in the previous code block.  Besides these, the only
2747   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2748   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2749   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2750   ** off all other flags.
2751   */
2752   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2753                SQLITE_OPEN_EXCLUSIVE |
2754                SQLITE_OPEN_MAIN_DB |
2755                SQLITE_OPEN_TEMP_DB |
2756                SQLITE_OPEN_TRANSIENT_DB |
2757                SQLITE_OPEN_MAIN_JOURNAL |
2758                SQLITE_OPEN_TEMP_JOURNAL |
2759                SQLITE_OPEN_SUBJOURNAL |
2760                SQLITE_OPEN_MASTER_JOURNAL |
2761                SQLITE_OPEN_NOMUTEX |
2762                SQLITE_OPEN_FULLMUTEX |
2763                SQLITE_OPEN_WAL
2764              );
2765 
2766   /* Allocate the sqlite data structure */
2767   db = sqlite3MallocZero( sizeof(sqlite3) );
2768   if( db==0 ) goto opendb_out;
2769   if( isThreadsafe ){
2770     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2771     if( db->mutex==0 ){
2772       sqlite3_free(db);
2773       db = 0;
2774       goto opendb_out;
2775     }
2776   }
2777   sqlite3_mutex_enter(db->mutex);
2778   db->errMask = 0xff;
2779   db->nDb = 2;
2780   db->magic = SQLITE_MAGIC_BUSY;
2781   db->aDb = db->aDbStatic;
2782 
2783   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2784   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2785   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2786   db->autoCommit = 1;
2787   db->nextAutovac = -1;
2788   db->szMmap = sqlite3GlobalConfig.szMmap;
2789   db->nextPagesize = 0;
2790   db->nMaxSorterMmap = 0x7FFFFFFF;
2791   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2792 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2793                  | SQLITE_AutoIndex
2794 #endif
2795 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2796                  | SQLITE_CkptFullFSync
2797 #endif
2798 #if SQLITE_DEFAULT_FILE_FORMAT<4
2799                  | SQLITE_LegacyFileFmt
2800 #endif
2801 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2802                  | SQLITE_LoadExtension
2803 #endif
2804 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2805                  | SQLITE_RecTriggers
2806 #endif
2807 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2808                  | SQLITE_ForeignKeys
2809 #endif
2810 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2811                  | SQLITE_ReverseOrder
2812 #endif
2813 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2814                  | SQLITE_CellSizeCk
2815 #endif
2816 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
2817                  | SQLITE_Fts3Tokenizer
2818 #endif
2819       ;
2820   sqlite3HashInit(&db->aCollSeq);
2821 #ifndef SQLITE_OMIT_VIRTUALTABLE
2822   sqlite3HashInit(&db->aModule);
2823 #endif
2824 
2825   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2826   ** and UTF-16, so add a version for each to avoid any unnecessary
2827   ** conversions. The only error that can occur here is a malloc() failure.
2828   **
2829   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2830   ** functions:
2831   */
2832   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2833   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2834   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2835   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2836   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2837   if( db->mallocFailed ){
2838     goto opendb_out;
2839   }
2840   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2841   ** strings is BINARY.
2842   */
2843   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2844   assert( db->pDfltColl!=0 );
2845 
2846   /* Parse the filename/URI argument. */
2847   db->openFlags = flags;
2848   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2849   if( rc!=SQLITE_OK ){
2850     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2851     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2852     sqlite3_free(zErrMsg);
2853     goto opendb_out;
2854   }
2855 
2856   /* Open the backend database driver */
2857   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2858                         flags | SQLITE_OPEN_MAIN_DB);
2859   if( rc!=SQLITE_OK ){
2860     if( rc==SQLITE_IOERR_NOMEM ){
2861       rc = SQLITE_NOMEM_BKPT;
2862     }
2863     sqlite3Error(db, rc);
2864     goto opendb_out;
2865   }
2866   sqlite3BtreeEnter(db->aDb[0].pBt);
2867   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2868   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2869   sqlite3BtreeLeave(db->aDb[0].pBt);
2870   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2871 
2872   /* The default safety_level for the main database is FULL; for the temp
2873   ** database it is OFF. This matches the pager layer defaults.
2874   */
2875   db->aDb[0].zName = "main";
2876   db->aDb[0].safety_level = PAGER_SYNCHRONOUS_FULL;
2877   db->aDb[1].zName = "temp";
2878   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
2879 
2880   db->magic = SQLITE_MAGIC_OPEN;
2881   if( db->mallocFailed ){
2882     goto opendb_out;
2883   }
2884 
2885   /* Register all built-in functions, but do not attempt to read the
2886   ** database schema yet. This is delayed until the first time the database
2887   ** is accessed.
2888   */
2889   sqlite3Error(db, SQLITE_OK);
2890   sqlite3RegisterPerConnectionBuiltinFunctions(db);
2891 
2892   /* Load automatic extensions - extensions that have been registered
2893   ** using the sqlite3_automatic_extension() API.
2894   */
2895   rc = sqlite3_errcode(db);
2896   if( rc==SQLITE_OK ){
2897     sqlite3AutoLoadExtensions(db);
2898     rc = sqlite3_errcode(db);
2899     if( rc!=SQLITE_OK ){
2900       goto opendb_out;
2901     }
2902   }
2903 
2904 #ifdef SQLITE_ENABLE_FTS1
2905   if( !db->mallocFailed ){
2906     extern int sqlite3Fts1Init(sqlite3*);
2907     rc = sqlite3Fts1Init(db);
2908   }
2909 #endif
2910 
2911 #ifdef SQLITE_ENABLE_FTS2
2912   if( !db->mallocFailed && rc==SQLITE_OK ){
2913     extern int sqlite3Fts2Init(sqlite3*);
2914     rc = sqlite3Fts2Init(db);
2915   }
2916 #endif
2917 
2918 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
2919   if( !db->mallocFailed && rc==SQLITE_OK ){
2920     rc = sqlite3Fts3Init(db);
2921   }
2922 #endif
2923 
2924 #ifdef SQLITE_ENABLE_FTS5
2925   if( !db->mallocFailed && rc==SQLITE_OK ){
2926     rc = sqlite3Fts5Init(db);
2927   }
2928 #endif
2929 
2930 #ifdef SQLITE_ENABLE_ICU
2931   if( !db->mallocFailed && rc==SQLITE_OK ){
2932     rc = sqlite3IcuInit(db);
2933   }
2934 #endif
2935 
2936 #ifdef SQLITE_ENABLE_RTREE
2937   if( !db->mallocFailed && rc==SQLITE_OK){
2938     rc = sqlite3RtreeInit(db);
2939   }
2940 #endif
2941 
2942 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
2943   if( !db->mallocFailed && rc==SQLITE_OK){
2944     rc = sqlite3DbstatRegister(db);
2945   }
2946 #endif
2947 
2948 #ifdef SQLITE_ENABLE_JSON1
2949   if( !db->mallocFailed && rc==SQLITE_OK){
2950     rc = sqlite3Json1Init(db);
2951   }
2952 #endif
2953 
2954   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2955   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2956   ** mode.  Doing nothing at all also makes NORMAL the default.
2957   */
2958 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2959   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2960   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2961                           SQLITE_DEFAULT_LOCKING_MODE);
2962 #endif
2963 
2964   if( rc ) sqlite3Error(db, rc);
2965 
2966   /* Enable the lookaside-malloc subsystem */
2967   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2968                         sqlite3GlobalConfig.nLookaside);
2969 
2970   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2971 
2972 opendb_out:
2973   if( db ){
2974     assert( db->mutex!=0 || isThreadsafe==0
2975            || sqlite3GlobalConfig.bFullMutex==0 );
2976     sqlite3_mutex_leave(db->mutex);
2977   }
2978   rc = sqlite3_errcode(db);
2979   assert( db!=0 || rc==SQLITE_NOMEM );
2980   if( rc==SQLITE_NOMEM ){
2981     sqlite3_close(db);
2982     db = 0;
2983   }else if( rc!=SQLITE_OK ){
2984     db->magic = SQLITE_MAGIC_SICK;
2985   }
2986   *ppDb = db;
2987 #ifdef SQLITE_ENABLE_SQLLOG
2988   if( sqlite3GlobalConfig.xSqllog ){
2989     /* Opening a db handle. Fourth parameter is passed 0. */
2990     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2991     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2992   }
2993 #endif
2994 #if defined(SQLITE_HAS_CODEC)
2995   if( rc==SQLITE_OK ){
2996     const char *zHexKey = sqlite3_uri_parameter(zOpen, "hexkey");
2997     if( zHexKey && zHexKey[0] ){
2998       u8 iByte;
2999       int i;
3000       char zKey[40];
3001       for(i=0, iByte=0; i<sizeof(zKey)*2 && sqlite3Isxdigit(zHexKey[i]); i++){
3002         iByte = (iByte<<4) + sqlite3HexToInt(zHexKey[i]);
3003         if( (i&1)!=0 ) zKey[i/2] = iByte;
3004       }
3005       sqlite3_key_v2(db, 0, zKey, i/2);
3006     }
3007   }
3008 #endif
3009   sqlite3_free(zOpen);
3010   return rc & 0xff;
3011 }
3012 
3013 /*
3014 ** Open a new database handle.
3015 */
3016 int sqlite3_open(
3017   const char *zFilename,
3018   sqlite3 **ppDb
3019 ){
3020   return openDatabase(zFilename, ppDb,
3021                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3022 }
3023 int sqlite3_open_v2(
3024   const char *filename,   /* Database filename (UTF-8) */
3025   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3026   int flags,              /* Flags */
3027   const char *zVfs        /* Name of VFS module to use */
3028 ){
3029   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3030 }
3031 
3032 #ifndef SQLITE_OMIT_UTF16
3033 /*
3034 ** Open a new database handle.
3035 */
3036 int sqlite3_open16(
3037   const void *zFilename,
3038   sqlite3 **ppDb
3039 ){
3040   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3041   sqlite3_value *pVal;
3042   int rc;
3043 
3044 #ifdef SQLITE_ENABLE_API_ARMOR
3045   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3046 #endif
3047   *ppDb = 0;
3048 #ifndef SQLITE_OMIT_AUTOINIT
3049   rc = sqlite3_initialize();
3050   if( rc ) return rc;
3051 #endif
3052   if( zFilename==0 ) zFilename = "\000\000";
3053   pVal = sqlite3ValueNew(0);
3054   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3055   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3056   if( zFilename8 ){
3057     rc = openDatabase(zFilename8, ppDb,
3058                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3059     assert( *ppDb || rc==SQLITE_NOMEM );
3060     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3061       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3062     }
3063   }else{
3064     rc = SQLITE_NOMEM_BKPT;
3065   }
3066   sqlite3ValueFree(pVal);
3067 
3068   return rc & 0xff;
3069 }
3070 #endif /* SQLITE_OMIT_UTF16 */
3071 
3072 /*
3073 ** Register a new collation sequence with the database handle db.
3074 */
3075 int sqlite3_create_collation(
3076   sqlite3* db,
3077   const char *zName,
3078   int enc,
3079   void* pCtx,
3080   int(*xCompare)(void*,int,const void*,int,const void*)
3081 ){
3082   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3083 }
3084 
3085 /*
3086 ** Register a new collation sequence with the database handle db.
3087 */
3088 int sqlite3_create_collation_v2(
3089   sqlite3* db,
3090   const char *zName,
3091   int enc,
3092   void* pCtx,
3093   int(*xCompare)(void*,int,const void*,int,const void*),
3094   void(*xDel)(void*)
3095 ){
3096   int rc;
3097 
3098 #ifdef SQLITE_ENABLE_API_ARMOR
3099   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3100 #endif
3101   sqlite3_mutex_enter(db->mutex);
3102   assert( !db->mallocFailed );
3103   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3104   rc = sqlite3ApiExit(db, rc);
3105   sqlite3_mutex_leave(db->mutex);
3106   return rc;
3107 }
3108 
3109 #ifndef SQLITE_OMIT_UTF16
3110 /*
3111 ** Register a new collation sequence with the database handle db.
3112 */
3113 int sqlite3_create_collation16(
3114   sqlite3* db,
3115   const void *zName,
3116   int enc,
3117   void* pCtx,
3118   int(*xCompare)(void*,int,const void*,int,const void*)
3119 ){
3120   int rc = SQLITE_OK;
3121   char *zName8;
3122 
3123 #ifdef SQLITE_ENABLE_API_ARMOR
3124   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3125 #endif
3126   sqlite3_mutex_enter(db->mutex);
3127   assert( !db->mallocFailed );
3128   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3129   if( zName8 ){
3130     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3131     sqlite3DbFree(db, zName8);
3132   }
3133   rc = sqlite3ApiExit(db, rc);
3134   sqlite3_mutex_leave(db->mutex);
3135   return rc;
3136 }
3137 #endif /* SQLITE_OMIT_UTF16 */
3138 
3139 /*
3140 ** Register a collation sequence factory callback with the database handle
3141 ** db. Replace any previously installed collation sequence factory.
3142 */
3143 int sqlite3_collation_needed(
3144   sqlite3 *db,
3145   void *pCollNeededArg,
3146   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3147 ){
3148 #ifdef SQLITE_ENABLE_API_ARMOR
3149   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3150 #endif
3151   sqlite3_mutex_enter(db->mutex);
3152   db->xCollNeeded = xCollNeeded;
3153   db->xCollNeeded16 = 0;
3154   db->pCollNeededArg = pCollNeededArg;
3155   sqlite3_mutex_leave(db->mutex);
3156   return SQLITE_OK;
3157 }
3158 
3159 #ifndef SQLITE_OMIT_UTF16
3160 /*
3161 ** Register a collation sequence factory callback with the database handle
3162 ** db. Replace any previously installed collation sequence factory.
3163 */
3164 int sqlite3_collation_needed16(
3165   sqlite3 *db,
3166   void *pCollNeededArg,
3167   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3168 ){
3169 #ifdef SQLITE_ENABLE_API_ARMOR
3170   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3171 #endif
3172   sqlite3_mutex_enter(db->mutex);
3173   db->xCollNeeded = 0;
3174   db->xCollNeeded16 = xCollNeeded16;
3175   db->pCollNeededArg = pCollNeededArg;
3176   sqlite3_mutex_leave(db->mutex);
3177   return SQLITE_OK;
3178 }
3179 #endif /* SQLITE_OMIT_UTF16 */
3180 
3181 #ifndef SQLITE_OMIT_DEPRECATED
3182 /*
3183 ** This function is now an anachronism. It used to be used to recover from a
3184 ** malloc() failure, but SQLite now does this automatically.
3185 */
3186 int sqlite3_global_recover(void){
3187   return SQLITE_OK;
3188 }
3189 #endif
3190 
3191 /*
3192 ** Test to see whether or not the database connection is in autocommit
3193 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3194 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3195 ** by the next COMMIT or ROLLBACK.
3196 */
3197 int sqlite3_get_autocommit(sqlite3 *db){
3198 #ifdef SQLITE_ENABLE_API_ARMOR
3199   if( !sqlite3SafetyCheckOk(db) ){
3200     (void)SQLITE_MISUSE_BKPT;
3201     return 0;
3202   }
3203 #endif
3204   return db->autoCommit;
3205 }
3206 
3207 /*
3208 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3209 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3210 ** constants.  They serve two purposes:
3211 **
3212 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3213 **       to detect when version error conditions occurs.
3214 **
3215 **   2.  Invoke sqlite3_log() to provide the source code location where
3216 **       a low-level error is first detected.
3217 */
3218 static int reportError(int iErr, int lineno, const char *zType){
3219   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3220               zType, lineno, 20+sqlite3_sourceid());
3221   return iErr;
3222 }
3223 int sqlite3CorruptError(int lineno){
3224   testcase( sqlite3GlobalConfig.xLog!=0 );
3225   return reportError(SQLITE_CORRUPT, lineno, "database corruption");
3226 }
3227 int sqlite3MisuseError(int lineno){
3228   testcase( sqlite3GlobalConfig.xLog!=0 );
3229   return reportError(SQLITE_MISUSE, lineno, "misuse");
3230 }
3231 int sqlite3CantopenError(int lineno){
3232   testcase( sqlite3GlobalConfig.xLog!=0 );
3233   return reportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3234 }
3235 #ifdef SQLITE_DEBUG
3236 int sqlite3NomemError(int lineno){
3237   testcase( sqlite3GlobalConfig.xLog!=0 );
3238   return reportError(SQLITE_NOMEM, lineno, "OOM");
3239 }
3240 int sqlite3IoerrnomemError(int lineno){
3241   testcase( sqlite3GlobalConfig.xLog!=0 );
3242   return reportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3243 }
3244 #endif
3245 
3246 #ifndef SQLITE_OMIT_DEPRECATED
3247 /*
3248 ** This is a convenience routine that makes sure that all thread-specific
3249 ** data for this thread has been deallocated.
3250 **
3251 ** SQLite no longer uses thread-specific data so this routine is now a
3252 ** no-op.  It is retained for historical compatibility.
3253 */
3254 void sqlite3_thread_cleanup(void){
3255 }
3256 #endif
3257 
3258 /*
3259 ** Return meta information about a specific column of a database table.
3260 ** See comment in sqlite3.h (sqlite.h.in) for details.
3261 */
3262 int sqlite3_table_column_metadata(
3263   sqlite3 *db,                /* Connection handle */
3264   const char *zDbName,        /* Database name or NULL */
3265   const char *zTableName,     /* Table name */
3266   const char *zColumnName,    /* Column name */
3267   char const **pzDataType,    /* OUTPUT: Declared data type */
3268   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3269   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3270   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3271   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3272 ){
3273   int rc;
3274   char *zErrMsg = 0;
3275   Table *pTab = 0;
3276   Column *pCol = 0;
3277   int iCol = 0;
3278   char const *zDataType = 0;
3279   char const *zCollSeq = 0;
3280   int notnull = 0;
3281   int primarykey = 0;
3282   int autoinc = 0;
3283 
3284 
3285 #ifdef SQLITE_ENABLE_API_ARMOR
3286   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3287     return SQLITE_MISUSE_BKPT;
3288   }
3289 #endif
3290 
3291   /* Ensure the database schema has been loaded */
3292   sqlite3_mutex_enter(db->mutex);
3293   sqlite3BtreeEnterAll(db);
3294   rc = sqlite3Init(db, &zErrMsg);
3295   if( SQLITE_OK!=rc ){
3296     goto error_out;
3297   }
3298 
3299   /* Locate the table in question */
3300   pTab = sqlite3FindTable(db, zTableName, zDbName);
3301   if( !pTab || pTab->pSelect ){
3302     pTab = 0;
3303     goto error_out;
3304   }
3305 
3306   /* Find the column for which info is requested */
3307   if( zColumnName==0 ){
3308     /* Query for existance of table only */
3309   }else{
3310     for(iCol=0; iCol<pTab->nCol; iCol++){
3311       pCol = &pTab->aCol[iCol];
3312       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3313         break;
3314       }
3315     }
3316     if( iCol==pTab->nCol ){
3317       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3318         iCol = pTab->iPKey;
3319         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3320       }else{
3321         pTab = 0;
3322         goto error_out;
3323       }
3324     }
3325   }
3326 
3327   /* The following block stores the meta information that will be returned
3328   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3329   ** and autoinc. At this point there are two possibilities:
3330   **
3331   **     1. The specified column name was rowid", "oid" or "_rowid_"
3332   **        and there is no explicitly declared IPK column.
3333   **
3334   **     2. The table is not a view and the column name identified an
3335   **        explicitly declared column. Copy meta information from *pCol.
3336   */
3337   if( pCol ){
3338     zDataType = pCol->zType;
3339     zCollSeq = pCol->zColl;
3340     notnull = pCol->notNull!=0;
3341     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3342     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3343   }else{
3344     zDataType = "INTEGER";
3345     primarykey = 1;
3346   }
3347   if( !zCollSeq ){
3348     zCollSeq = sqlite3StrBINARY;
3349   }
3350 
3351 error_out:
3352   sqlite3BtreeLeaveAll(db);
3353 
3354   /* Whether the function call succeeded or failed, set the output parameters
3355   ** to whatever their local counterparts contain. If an error did occur,
3356   ** this has the effect of zeroing all output parameters.
3357   */
3358   if( pzDataType ) *pzDataType = zDataType;
3359   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3360   if( pNotNull ) *pNotNull = notnull;
3361   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3362   if( pAutoinc ) *pAutoinc = autoinc;
3363 
3364   if( SQLITE_OK==rc && !pTab ){
3365     sqlite3DbFree(db, zErrMsg);
3366     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3367         zColumnName);
3368     rc = SQLITE_ERROR;
3369   }
3370   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3371   sqlite3DbFree(db, zErrMsg);
3372   rc = sqlite3ApiExit(db, rc);
3373   sqlite3_mutex_leave(db->mutex);
3374   return rc;
3375 }
3376 
3377 /*
3378 ** Sleep for a little while.  Return the amount of time slept.
3379 */
3380 int sqlite3_sleep(int ms){
3381   sqlite3_vfs *pVfs;
3382   int rc;
3383   pVfs = sqlite3_vfs_find(0);
3384   if( pVfs==0 ) return 0;
3385 
3386   /* This function works in milliseconds, but the underlying OsSleep()
3387   ** API uses microseconds. Hence the 1000's.
3388   */
3389   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3390   return rc;
3391 }
3392 
3393 /*
3394 ** Enable or disable the extended result codes.
3395 */
3396 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3397 #ifdef SQLITE_ENABLE_API_ARMOR
3398   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3399 #endif
3400   sqlite3_mutex_enter(db->mutex);
3401   db->errMask = onoff ? 0xffffffff : 0xff;
3402   sqlite3_mutex_leave(db->mutex);
3403   return SQLITE_OK;
3404 }
3405 
3406 /*
3407 ** Invoke the xFileControl method on a particular database.
3408 */
3409 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3410   int rc = SQLITE_ERROR;
3411   Btree *pBtree;
3412 
3413 #ifdef SQLITE_ENABLE_API_ARMOR
3414   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3415 #endif
3416   sqlite3_mutex_enter(db->mutex);
3417   pBtree = sqlite3DbNameToBtree(db, zDbName);
3418   if( pBtree ){
3419     Pager *pPager;
3420     sqlite3_file *fd;
3421     sqlite3BtreeEnter(pBtree);
3422     pPager = sqlite3BtreePager(pBtree);
3423     assert( pPager!=0 );
3424     fd = sqlite3PagerFile(pPager);
3425     assert( fd!=0 );
3426     if( op==SQLITE_FCNTL_FILE_POINTER ){
3427       *(sqlite3_file**)pArg = fd;
3428       rc = SQLITE_OK;
3429     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3430       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3431       rc = SQLITE_OK;
3432     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3433       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3434       rc = SQLITE_OK;
3435     }else if( fd->pMethods ){
3436       rc = sqlite3OsFileControl(fd, op, pArg);
3437     }else{
3438       rc = SQLITE_NOTFOUND;
3439     }
3440     sqlite3BtreeLeave(pBtree);
3441   }
3442   sqlite3_mutex_leave(db->mutex);
3443   return rc;
3444 }
3445 
3446 /*
3447 ** Interface to the testing logic.
3448 */
3449 int sqlite3_test_control(int op, ...){
3450   int rc = 0;
3451 #ifdef SQLITE_OMIT_BUILTIN_TEST
3452   UNUSED_PARAMETER(op);
3453 #else
3454   va_list ap;
3455   va_start(ap, op);
3456   switch( op ){
3457 
3458     /*
3459     ** Save the current state of the PRNG.
3460     */
3461     case SQLITE_TESTCTRL_PRNG_SAVE: {
3462       sqlite3PrngSaveState();
3463       break;
3464     }
3465 
3466     /*
3467     ** Restore the state of the PRNG to the last state saved using
3468     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3469     ** this verb acts like PRNG_RESET.
3470     */
3471     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3472       sqlite3PrngRestoreState();
3473       break;
3474     }
3475 
3476     /*
3477     ** Reset the PRNG back to its uninitialized state.  The next call
3478     ** to sqlite3_randomness() will reseed the PRNG using a single call
3479     ** to the xRandomness method of the default VFS.
3480     */
3481     case SQLITE_TESTCTRL_PRNG_RESET: {
3482       sqlite3_randomness(0,0);
3483       break;
3484     }
3485 
3486     /*
3487     **  sqlite3_test_control(BITVEC_TEST, size, program)
3488     **
3489     ** Run a test against a Bitvec object of size.  The program argument
3490     ** is an array of integers that defines the test.  Return -1 on a
3491     ** memory allocation error, 0 on success, or non-zero for an error.
3492     ** See the sqlite3BitvecBuiltinTest() for additional information.
3493     */
3494     case SQLITE_TESTCTRL_BITVEC_TEST: {
3495       int sz = va_arg(ap, int);
3496       int *aProg = va_arg(ap, int*);
3497       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3498       break;
3499     }
3500 
3501     /*
3502     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3503     **
3504     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3505     ** if xCallback is not NULL.
3506     **
3507     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3508     ** is called immediately after installing the new callback and the return
3509     ** value from sqlite3FaultSim(0) becomes the return from
3510     ** sqlite3_test_control().
3511     */
3512     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3513       /* MSVC is picky about pulling func ptrs from va lists.
3514       ** http://support.microsoft.com/kb/47961
3515       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3516       */
3517       typedef int(*TESTCALLBACKFUNC_t)(int);
3518       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3519       rc = sqlite3FaultSim(0);
3520       break;
3521     }
3522 
3523     /*
3524     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3525     **
3526     ** Register hooks to call to indicate which malloc() failures
3527     ** are benign.
3528     */
3529     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3530       typedef void (*void_function)(void);
3531       void_function xBenignBegin;
3532       void_function xBenignEnd;
3533       xBenignBegin = va_arg(ap, void_function);
3534       xBenignEnd = va_arg(ap, void_function);
3535       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3536       break;
3537     }
3538 
3539     /*
3540     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3541     **
3542     ** Set the PENDING byte to the value in the argument, if X>0.
3543     ** Make no changes if X==0.  Return the value of the pending byte
3544     ** as it existing before this routine was called.
3545     **
3546     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3547     ** an incompatible database file format.  Changing the PENDING byte
3548     ** while any database connection is open results in undefined and
3549     ** deleterious behavior.
3550     */
3551     case SQLITE_TESTCTRL_PENDING_BYTE: {
3552       rc = PENDING_BYTE;
3553 #ifndef SQLITE_OMIT_WSD
3554       {
3555         unsigned int newVal = va_arg(ap, unsigned int);
3556         if( newVal ) sqlite3PendingByte = newVal;
3557       }
3558 #endif
3559       break;
3560     }
3561 
3562     /*
3563     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3564     **
3565     ** This action provides a run-time test to see whether or not
3566     ** assert() was enabled at compile-time.  If X is true and assert()
3567     ** is enabled, then the return value is true.  If X is true and
3568     ** assert() is disabled, then the return value is zero.  If X is
3569     ** false and assert() is enabled, then the assertion fires and the
3570     ** process aborts.  If X is false and assert() is disabled, then the
3571     ** return value is zero.
3572     */
3573     case SQLITE_TESTCTRL_ASSERT: {
3574       volatile int x = 0;
3575       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3576       rc = x;
3577       break;
3578     }
3579 
3580 
3581     /*
3582     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3583     **
3584     ** This action provides a run-time test to see how the ALWAYS and
3585     ** NEVER macros were defined at compile-time.
3586     **
3587     ** The return value is ALWAYS(X).
3588     **
3589     ** The recommended test is X==2.  If the return value is 2, that means
3590     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3591     ** default setting.  If the return value is 1, then ALWAYS() is either
3592     ** hard-coded to true or else it asserts if its argument is false.
3593     ** The first behavior (hard-coded to true) is the case if
3594     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3595     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3596     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3597     **
3598     ** The run-time test procedure might look something like this:
3599     **
3600     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3601     **      // ALWAYS() and NEVER() are no-op pass-through macros
3602     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3603     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3604     **    }else{
3605     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3606     **    }
3607     */
3608     case SQLITE_TESTCTRL_ALWAYS: {
3609       int x = va_arg(ap,int);
3610       rc = ALWAYS(x);
3611       break;
3612     }
3613 
3614     /*
3615     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3616     **
3617     ** The integer returned reveals the byte-order of the computer on which
3618     ** SQLite is running:
3619     **
3620     **       1     big-endian,    determined at run-time
3621     **      10     little-endian, determined at run-time
3622     **  432101     big-endian,    determined at compile-time
3623     **  123410     little-endian, determined at compile-time
3624     */
3625     case SQLITE_TESTCTRL_BYTEORDER: {
3626       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3627       break;
3628     }
3629 
3630     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3631     **
3632     ** Set the nReserve size to N for the main database on the database
3633     ** connection db.
3634     */
3635     case SQLITE_TESTCTRL_RESERVE: {
3636       sqlite3 *db = va_arg(ap, sqlite3*);
3637       int x = va_arg(ap,int);
3638       sqlite3_mutex_enter(db->mutex);
3639       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3640       sqlite3_mutex_leave(db->mutex);
3641       break;
3642     }
3643 
3644     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3645     **
3646     ** Enable or disable various optimizations for testing purposes.  The
3647     ** argument N is a bitmask of optimizations to be disabled.  For normal
3648     ** operation N should be 0.  The idea is that a test program (like the
3649     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3650     ** with various optimizations disabled to verify that the same answer
3651     ** is obtained in every case.
3652     */
3653     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3654       sqlite3 *db = va_arg(ap, sqlite3*);
3655       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3656       break;
3657     }
3658 
3659 #ifdef SQLITE_N_KEYWORD
3660     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3661     **
3662     ** If zWord is a keyword recognized by the parser, then return the
3663     ** number of keywords.  Or if zWord is not a keyword, return 0.
3664     **
3665     ** This test feature is only available in the amalgamation since
3666     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3667     ** is built using separate source files.
3668     */
3669     case SQLITE_TESTCTRL_ISKEYWORD: {
3670       const char *zWord = va_arg(ap, const char*);
3671       int n = sqlite3Strlen30(zWord);
3672       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3673       break;
3674     }
3675 #endif
3676 
3677     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3678     **
3679     ** Pass pFree into sqlite3ScratchFree().
3680     ** If sz>0 then allocate a scratch buffer into pNew.
3681     */
3682     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3683       void *pFree, **ppNew;
3684       int sz;
3685       sz = va_arg(ap, int);
3686       ppNew = va_arg(ap, void**);
3687       pFree = va_arg(ap, void*);
3688       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3689       sqlite3ScratchFree(pFree);
3690       break;
3691     }
3692 
3693     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3694     **
3695     ** If parameter onoff is non-zero, configure the wrappers so that all
3696     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3697     ** undo this setting.
3698     */
3699     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3700       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3701       break;
3702     }
3703 
3704     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3705     **
3706     ** Set or clear a flag that indicates that the database file is always well-
3707     ** formed and never corrupt.  This flag is clear by default, indicating that
3708     ** database files might have arbitrary corruption.  Setting the flag during
3709     ** testing causes certain assert() statements in the code to be activated
3710     ** that demonstrat invariants on well-formed database files.
3711     */
3712     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3713       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3714       break;
3715     }
3716 
3717 
3718     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3719     **
3720     ** Set the VDBE coverage callback function to xCallback with context
3721     ** pointer ptr.
3722     */
3723     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3724 #ifdef SQLITE_VDBE_COVERAGE
3725       typedef void (*branch_callback)(void*,int,u8,u8);
3726       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3727       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3728 #endif
3729       break;
3730     }
3731 
3732     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3733     case SQLITE_TESTCTRL_SORTER_MMAP: {
3734       sqlite3 *db = va_arg(ap, sqlite3*);
3735       db->nMaxSorterMmap = va_arg(ap, int);
3736       break;
3737     }
3738 
3739     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3740     **
3741     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3742     ** not.
3743     */
3744     case SQLITE_TESTCTRL_ISINIT: {
3745       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3746       break;
3747     }
3748 
3749     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3750     **
3751     ** This test control is used to create imposter tables.  "db" is a pointer
3752     ** to the database connection.  dbName is the database name (ex: "main" or
3753     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3754     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3755     ** table should connect.
3756     **
3757     ** Enable imposter mode only when the schema has already been parsed.  Then
3758     ** run a single CREATE TABLE statement to construct the imposter table in
3759     ** the parsed schema.  Then turn imposter mode back off again.
3760     **
3761     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3762     ** the schema to be reparsed the next time it is needed.  This has the
3763     ** effect of erasing all imposter tables.
3764     */
3765     case SQLITE_TESTCTRL_IMPOSTER: {
3766       sqlite3 *db = va_arg(ap, sqlite3*);
3767       sqlite3_mutex_enter(db->mutex);
3768       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3769       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3770       db->init.newTnum = va_arg(ap,int);
3771       if( db->init.busy==0 && db->init.newTnum>0 ){
3772         sqlite3ResetAllSchemasOfConnection(db);
3773       }
3774       sqlite3_mutex_leave(db->mutex);
3775       break;
3776     }
3777   }
3778   va_end(ap);
3779 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3780   return rc;
3781 }
3782 
3783 /*
3784 ** This is a utility routine, useful to VFS implementations, that checks
3785 ** to see if a database file was a URI that contained a specific query
3786 ** parameter, and if so obtains the value of the query parameter.
3787 **
3788 ** The zFilename argument is the filename pointer passed into the xOpen()
3789 ** method of a VFS implementation.  The zParam argument is the name of the
3790 ** query parameter we seek.  This routine returns the value of the zParam
3791 ** parameter if it exists.  If the parameter does not exist, this routine
3792 ** returns a NULL pointer.
3793 */
3794 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3795   if( zFilename==0 || zParam==0 ) return 0;
3796   zFilename += sqlite3Strlen30(zFilename) + 1;
3797   while( zFilename[0] ){
3798     int x = strcmp(zFilename, zParam);
3799     zFilename += sqlite3Strlen30(zFilename) + 1;
3800     if( x==0 ) return zFilename;
3801     zFilename += sqlite3Strlen30(zFilename) + 1;
3802   }
3803   return 0;
3804 }
3805 
3806 /*
3807 ** Return a boolean value for a query parameter.
3808 */
3809 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3810   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3811   bDflt = bDflt!=0;
3812   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3813 }
3814 
3815 /*
3816 ** Return a 64-bit integer value for a query parameter.
3817 */
3818 sqlite3_int64 sqlite3_uri_int64(
3819   const char *zFilename,    /* Filename as passed to xOpen */
3820   const char *zParam,       /* URI parameter sought */
3821   sqlite3_int64 bDflt       /* return if parameter is missing */
3822 ){
3823   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3824   sqlite3_int64 v;
3825   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3826     bDflt = v;
3827   }
3828   return bDflt;
3829 }
3830 
3831 /*
3832 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3833 */
3834 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3835   int i;
3836   for(i=0; i<db->nDb; i++){
3837     if( db->aDb[i].pBt
3838      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3839     ){
3840       return db->aDb[i].pBt;
3841     }
3842   }
3843   return 0;
3844 }
3845 
3846 /*
3847 ** Return the filename of the database associated with a database
3848 ** connection.
3849 */
3850 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3851   Btree *pBt;
3852 #ifdef SQLITE_ENABLE_API_ARMOR
3853   if( !sqlite3SafetyCheckOk(db) ){
3854     (void)SQLITE_MISUSE_BKPT;
3855     return 0;
3856   }
3857 #endif
3858   pBt = sqlite3DbNameToBtree(db, zDbName);
3859   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3860 }
3861 
3862 /*
3863 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3864 ** no such database exists.
3865 */
3866 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3867   Btree *pBt;
3868 #ifdef SQLITE_ENABLE_API_ARMOR
3869   if( !sqlite3SafetyCheckOk(db) ){
3870     (void)SQLITE_MISUSE_BKPT;
3871     return -1;
3872   }
3873 #endif
3874   pBt = sqlite3DbNameToBtree(db, zDbName);
3875   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3876 }
3877 
3878 #ifdef SQLITE_ENABLE_SNAPSHOT
3879 /*
3880 ** Obtain a snapshot handle for the snapshot of database zDb currently
3881 ** being read by handle db.
3882 */
3883 int sqlite3_snapshot_get(
3884   sqlite3 *db,
3885   const char *zDb,
3886   sqlite3_snapshot **ppSnapshot
3887 ){
3888   int rc = SQLITE_ERROR;
3889 #ifndef SQLITE_OMIT_WAL
3890   int iDb;
3891 
3892 #ifdef SQLITE_ENABLE_API_ARMOR
3893   if( !sqlite3SafetyCheckOk(db) ){
3894     return SQLITE_MISUSE_BKPT;
3895   }
3896 #endif
3897   sqlite3_mutex_enter(db->mutex);
3898 
3899   iDb = sqlite3FindDbName(db, zDb);
3900   if( iDb==0 || iDb>1 ){
3901     Btree *pBt = db->aDb[iDb].pBt;
3902     if( 0==sqlite3BtreeIsInTrans(pBt) ){
3903       rc = sqlite3BtreeBeginTrans(pBt, 0);
3904       if( rc==SQLITE_OK ){
3905         rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
3906       }
3907     }
3908   }
3909 
3910   sqlite3_mutex_leave(db->mutex);
3911 #endif   /* SQLITE_OMIT_WAL */
3912   return rc;
3913 }
3914 
3915 /*
3916 ** Open a read-transaction on the snapshot idendified by pSnapshot.
3917 */
3918 int sqlite3_snapshot_open(
3919   sqlite3 *db,
3920   const char *zDb,
3921   sqlite3_snapshot *pSnapshot
3922 ){
3923   int rc = SQLITE_ERROR;
3924 #ifndef SQLITE_OMIT_WAL
3925 
3926 #ifdef SQLITE_ENABLE_API_ARMOR
3927   if( !sqlite3SafetyCheckOk(db) ){
3928     return SQLITE_MISUSE_BKPT;
3929   }
3930 #endif
3931   sqlite3_mutex_enter(db->mutex);
3932   if( db->autoCommit==0 ){
3933     int iDb;
3934     iDb = sqlite3FindDbName(db, zDb);
3935     if( iDb==0 || iDb>1 ){
3936       Btree *pBt = db->aDb[iDb].pBt;
3937       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
3938         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
3939         if( rc==SQLITE_OK ){
3940           rc = sqlite3BtreeBeginTrans(pBt, 0);
3941           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
3942         }
3943       }
3944     }
3945   }
3946 
3947   sqlite3_mutex_leave(db->mutex);
3948 #endif   /* SQLITE_OMIT_WAL */
3949   return rc;
3950 }
3951 
3952 /*
3953 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
3954 */
3955 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
3956   sqlite3_free(pSnapshot);
3957 }
3958 #endif /* SQLITE_ENABLE_SNAPSHOT */
3959