xref: /sqlite-3.40.0/src/main.c (revision bd41d566)
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 
29 #ifndef SQLITE_AMALGAMATION
30 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
31 ** contains the text of SQLITE_VERSION macro.
32 */
33 const char sqlite3_version[] = SQLITE_VERSION;
34 #endif
35 
36 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
37 ** a pointer to the to the sqlite3_version[] string constant.
38 */
39 const char *sqlite3_libversion(void){ return sqlite3_version; }
40 
41 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
42 ** pointer to a string constant whose value is the same as the
43 ** SQLITE_SOURCE_ID C preprocessor macro.
44 */
45 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
46 
47 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
48 ** returns an integer equal to SQLITE_VERSION_NUMBER.
49 */
50 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
51 
52 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
53 ** zero if and only if SQLite was compiled with mutexing code omitted due to
54 ** the SQLITE_THREADSAFE compile-time option being set to 0.
55 */
56 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
57 
58 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
59 /*
60 ** If the following function pointer is not NULL and if
61 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
62 ** I/O active are written using this function.  These messages
63 ** are intended for debugging activity only.
64 */
65 /* not-private */ void (*sqlite3IoTrace)(const char*, ...) = 0;
66 #endif
67 
68 /*
69 ** If the following global variable points to a string which is the
70 ** name of a directory, then that directory will be used to store
71 ** temporary files.
72 **
73 ** See also the "PRAGMA temp_store_directory" SQL command.
74 */
75 char *sqlite3_temp_directory = 0;
76 
77 /*
78 ** If the following global variable points to a string which is the
79 ** name of a directory, then that directory will be used to store
80 ** all database files specified with a relative pathname.
81 **
82 ** See also the "PRAGMA data_store_directory" SQL command.
83 */
84 char *sqlite3_data_directory = 0;
85 
86 /*
87 ** Initialize SQLite.
88 **
89 ** This routine must be called to initialize the memory allocation,
90 ** VFS, and mutex subsystems prior to doing any serious work with
91 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
92 ** this routine will be called automatically by key routines such as
93 ** sqlite3_open().
94 **
95 ** This routine is a no-op except on its very first call for the process,
96 ** or for the first call after a call to sqlite3_shutdown.
97 **
98 ** The first thread to call this routine runs the initialization to
99 ** completion.  If subsequent threads call this routine before the first
100 ** thread has finished the initialization process, then the subsequent
101 ** threads must block until the first thread finishes with the initialization.
102 **
103 ** The first thread might call this routine recursively.  Recursive
104 ** calls to this routine should not block, of course.  Otherwise the
105 ** initialization process would never complete.
106 **
107 ** Let X be the first thread to enter this routine.  Let Y be some other
108 ** thread.  Then while the initial invocation of this routine by X is
109 ** incomplete, it is required that:
110 **
111 **    *  Calls to this routine from Y must block until the outer-most
112 **       call by X completes.
113 **
114 **    *  Recursive calls to this routine from thread X return immediately
115 **       without blocking.
116 */
117 int sqlite3_initialize(void){
118   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
119   int rc;                                      /* Result code */
120 #ifdef SQLITE_EXTRA_INIT
121   int bRunExtraInit = 0;                       /* Extra initialization needed */
122 #endif
123 
124 #ifdef SQLITE_OMIT_WSD
125   rc = sqlite3_wsd_init(4096, 24);
126   if( rc!=SQLITE_OK ){
127     return rc;
128   }
129 #endif
130 
131   /* If SQLite is already completely initialized, then this call
132   ** to sqlite3_initialize() should be a no-op.  But the initialization
133   ** must be complete.  So isInit must not be set until the very end
134   ** of this routine.
135   */
136   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
137 
138   /* Make sure the mutex subsystem is initialized.  If unable to
139   ** initialize the mutex subsystem, return early with the error.
140   ** If the system is so sick that we are unable to allocate a mutex,
141   ** there is not much SQLite is going to be able to do.
142   **
143   ** The mutex subsystem must take care of serializing its own
144   ** initialization.
145   */
146   rc = sqlite3MutexInit();
147   if( rc ) return rc;
148 
149   /* Initialize the malloc() system and the recursive pInitMutex mutex.
150   ** This operation is protected by the STATIC_MASTER mutex.  Note that
151   ** MutexAlloc() is called for a static mutex prior to initializing the
152   ** malloc subsystem - this implies that the allocation of a static
153   ** mutex must not require support from the malloc subsystem.
154   */
155   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
156   sqlite3_mutex_enter(pMaster);
157   sqlite3GlobalConfig.isMutexInit = 1;
158   if( !sqlite3GlobalConfig.isMallocInit ){
159     rc = sqlite3MallocInit();
160   }
161   if( rc==SQLITE_OK ){
162     sqlite3GlobalConfig.isMallocInit = 1;
163     if( !sqlite3GlobalConfig.pInitMutex ){
164       sqlite3GlobalConfig.pInitMutex =
165            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
166       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
167         rc = SQLITE_NOMEM;
168       }
169     }
170   }
171   if( rc==SQLITE_OK ){
172     sqlite3GlobalConfig.nRefInitMutex++;
173   }
174   sqlite3_mutex_leave(pMaster);
175 
176   /* If rc is not SQLITE_OK at this point, then either the malloc
177   ** subsystem could not be initialized or the system failed to allocate
178   ** the pInitMutex mutex. Return an error in either case.  */
179   if( rc!=SQLITE_OK ){
180     return rc;
181   }
182 
183   /* Do the rest of the initialization under the recursive mutex so
184   ** that we will be able to handle recursive calls into
185   ** sqlite3_initialize().  The recursive calls normally come through
186   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
187   ** recursive calls might also be possible.
188   **
189   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
190   ** to the xInit method, so the xInit method need not be threadsafe.
191   **
192   ** The following mutex is what serializes access to the appdef pcache xInit
193   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
194   ** call to sqlite3PcacheInitialize().
195   */
196   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
197   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
198     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
199     sqlite3GlobalConfig.inProgress = 1;
200     memset(pHash, 0, sizeof(sqlite3GlobalFunctions));
201     sqlite3RegisterGlobalFunctions();
202     if( sqlite3GlobalConfig.isPCacheInit==0 ){
203       rc = sqlite3PcacheInitialize();
204     }
205     if( rc==SQLITE_OK ){
206       sqlite3GlobalConfig.isPCacheInit = 1;
207       rc = sqlite3OsInit();
208     }
209     if( rc==SQLITE_OK ){
210       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
211           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
212       sqlite3GlobalConfig.isInit = 1;
213 #ifdef SQLITE_EXTRA_INIT
214       bRunExtraInit = 1;
215 #endif
216     }
217     sqlite3GlobalConfig.inProgress = 0;
218   }
219   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
220 
221   /* Go back under the static mutex and clean up the recursive
222   ** mutex to prevent a resource leak.
223   */
224   sqlite3_mutex_enter(pMaster);
225   sqlite3GlobalConfig.nRefInitMutex--;
226   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
227     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
228     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
229     sqlite3GlobalConfig.pInitMutex = 0;
230   }
231   sqlite3_mutex_leave(pMaster);
232 
233   /* The following is just a sanity check to make sure SQLite has
234   ** been compiled correctly.  It is important to run this code, but
235   ** we don't want to run it too often and soak up CPU cycles for no
236   ** reason.  So we run it once during initialization.
237   */
238 #ifndef NDEBUG
239 #ifndef SQLITE_OMIT_FLOATING_POINT
240   /* This section of code's only "output" is via assert() statements. */
241   if ( rc==SQLITE_OK ){
242     u64 x = (((u64)1)<<63)-1;
243     double y;
244     assert(sizeof(x)==8);
245     assert(sizeof(x)==sizeof(y));
246     memcpy(&y, &x, 8);
247     assert( sqlite3IsNaN(y) );
248   }
249 #endif
250 #endif
251 
252   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
253   ** compile-time option.
254   */
255 #ifdef SQLITE_EXTRA_INIT
256   if( bRunExtraInit ){
257     int SQLITE_EXTRA_INIT(const char*);
258     rc = SQLITE_EXTRA_INIT(0);
259   }
260 #endif
261 
262   return rc;
263 }
264 
265 /*
266 ** Undo the effects of sqlite3_initialize().  Must not be called while
267 ** there are outstanding database connections or memory allocations or
268 ** while any part of SQLite is otherwise in use in any thread.  This
269 ** routine is not threadsafe.  But it is safe to invoke this routine
270 ** on when SQLite is already shut down.  If SQLite is already shut down
271 ** when this routine is invoked, then this routine is a harmless no-op.
272 */
273 int sqlite3_shutdown(void){
274 #ifdef SQLITE_OMIT_WSD
275   int rc = sqlite3_wsd_init(4096, 24);
276   if( rc!=SQLITE_OK ){
277     return rc;
278   }
279 #endif
280 
281   if( sqlite3GlobalConfig.isInit ){
282 #ifdef SQLITE_EXTRA_SHUTDOWN
283     void SQLITE_EXTRA_SHUTDOWN(void);
284     SQLITE_EXTRA_SHUTDOWN();
285 #endif
286     sqlite3_os_end();
287     sqlite3_reset_auto_extension();
288     sqlite3GlobalConfig.isInit = 0;
289   }
290   if( sqlite3GlobalConfig.isPCacheInit ){
291     sqlite3PcacheShutdown();
292     sqlite3GlobalConfig.isPCacheInit = 0;
293   }
294   if( sqlite3GlobalConfig.isMallocInit ){
295     sqlite3MallocEnd();
296     sqlite3GlobalConfig.isMallocInit = 0;
297 
298 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
299     /* The heap subsystem has now been shutdown and these values are supposed
300     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
301     ** which would rely on that heap subsystem; therefore, make sure these
302     ** values cannot refer to heap memory that was just invalidated when the
303     ** heap subsystem was shutdown.  This is only done if the current call to
304     ** this function resulted in the heap subsystem actually being shutdown.
305     */
306     sqlite3_data_directory = 0;
307     sqlite3_temp_directory = 0;
308 #endif
309   }
310   if( sqlite3GlobalConfig.isMutexInit ){
311     sqlite3MutexEnd();
312     sqlite3GlobalConfig.isMutexInit = 0;
313   }
314 
315   return SQLITE_OK;
316 }
317 
318 /*
319 ** This API allows applications to modify the global configuration of
320 ** the SQLite library at run-time.
321 **
322 ** This routine should only be called when there are no outstanding
323 ** database connections or memory allocations.  This routine is not
324 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
325 ** behavior.
326 */
327 int sqlite3_config(int op, ...){
328   va_list ap;
329   int rc = SQLITE_OK;
330 
331   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
332   ** the SQLite library is in use. */
333   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
334 
335   va_start(ap, op);
336   switch( op ){
337 
338     /* Mutex configuration options are only available in a threadsafe
339     ** compile.
340     */
341 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
342     case SQLITE_CONFIG_SINGLETHREAD: {
343       /* Disable all mutexing */
344       sqlite3GlobalConfig.bCoreMutex = 0;
345       sqlite3GlobalConfig.bFullMutex = 0;
346       break;
347     }
348 #endif
349 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
350     case SQLITE_CONFIG_MULTITHREAD: {
351       /* Disable mutexing of database connections */
352       /* Enable mutexing of core data structures */
353       sqlite3GlobalConfig.bCoreMutex = 1;
354       sqlite3GlobalConfig.bFullMutex = 0;
355       break;
356     }
357 #endif
358 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
359     case SQLITE_CONFIG_SERIALIZED: {
360       /* Enable all mutexing */
361       sqlite3GlobalConfig.bCoreMutex = 1;
362       sqlite3GlobalConfig.bFullMutex = 1;
363       break;
364     }
365 #endif
366 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
367     case SQLITE_CONFIG_MUTEX: {
368       /* Specify an alternative mutex implementation */
369       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
370       break;
371     }
372 #endif
373 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
374     case SQLITE_CONFIG_GETMUTEX: {
375       /* Retrieve the current mutex implementation */
376       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
377       break;
378     }
379 #endif
380 
381     case SQLITE_CONFIG_MALLOC: {
382       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
383       ** single argument which is a pointer to an instance of the
384       ** sqlite3_mem_methods structure. The argument specifies alternative
385       ** low-level memory allocation routines to be used in place of the memory
386       ** allocation routines built into SQLite. */
387       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
388       break;
389     }
390     case SQLITE_CONFIG_GETMALLOC: {
391       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
392       ** single argument which is a pointer to an instance of the
393       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
394       ** filled with the currently defined memory allocation routines. */
395       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
396       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
397       break;
398     }
399     case SQLITE_CONFIG_MEMSTATUS: {
400       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
401       ** single argument of type int, interpreted as a boolean, which enables
402       ** or disables the collection of memory allocation statistics. */
403       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
404       break;
405     }
406     case SQLITE_CONFIG_SCRATCH: {
407       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
408       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
409       ** which the scratch allocations will be drawn, the size of each scratch
410       ** allocation (sz), and the maximum number of scratch allocations (N). */
411       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
412       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
413       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
414       break;
415     }
416     case SQLITE_CONFIG_PAGECACHE: {
417       /* EVIDENCE-OF: R-31408-40510 There are three arguments to
418       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory, the size
419       ** of each page buffer (sz), and the number of pages (N). */
420       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
421       sqlite3GlobalConfig.szPage = va_arg(ap, int);
422       sqlite3GlobalConfig.nPage = va_arg(ap, int);
423       break;
424     }
425     case SQLITE_CONFIG_PCACHE_HDRSZ: {
426       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
427       ** a single parameter which is a pointer to an integer and writes into
428       ** that integer the number of extra bytes per page required for each page
429       ** in SQLITE_CONFIG_PAGECACHE. */
430       *va_arg(ap, int*) =
431           sqlite3HeaderSizeBtree() +
432           sqlite3HeaderSizePcache() +
433           sqlite3HeaderSizePcache1();
434       break;
435     }
436 
437     case SQLITE_CONFIG_PCACHE: {
438       /* no-op */
439       break;
440     }
441     case SQLITE_CONFIG_GETPCACHE: {
442       /* now an error */
443       rc = SQLITE_ERROR;
444       break;
445     }
446 
447     case SQLITE_CONFIG_PCACHE2: {
448       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
449       ** single argument which is a pointer to an sqlite3_pcache_methods2
450       ** object. This object specifies the interface to a custom page cache
451       ** implementation. */
452       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
453       break;
454     }
455     case SQLITE_CONFIG_GETPCACHE2: {
456       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
457       ** single argument which is a pointer to an sqlite3_pcache_methods2
458       ** object. SQLite copies of the current page cache implementation into
459       ** that object. */
460       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
461         sqlite3PCacheSetDefault();
462       }
463       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
464       break;
465     }
466 
467 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
468 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
469 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
470 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
471     case SQLITE_CONFIG_HEAP: {
472       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
473       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
474       ** number of bytes in the memory buffer, and the minimum allocation size. */
475       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
476       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
477       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
478 
479       if( sqlite3GlobalConfig.mnReq<1 ){
480         sqlite3GlobalConfig.mnReq = 1;
481       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
482         /* cap min request size at 2^12 */
483         sqlite3GlobalConfig.mnReq = (1<<12);
484       }
485 
486       if( sqlite3GlobalConfig.pHeap==0 ){
487         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
488         ** is NULL, then SQLite reverts to using its default memory allocator
489         ** (the system malloc() implementation), undoing any prior invocation of
490         ** SQLITE_CONFIG_MALLOC.
491         **
492         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
493         ** revert to its default implementation when sqlite3_initialize() is run
494         */
495         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
496       }else{
497         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
498         ** alternative memory allocator is engaged to handle all of SQLites
499         ** memory allocation needs. */
500 #ifdef SQLITE_ENABLE_MEMSYS3
501         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
502 #endif
503 #ifdef SQLITE_ENABLE_MEMSYS5
504         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
505 #endif
506       }
507       break;
508     }
509 #endif
510 
511     case SQLITE_CONFIG_LOOKASIDE: {
512       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
513       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
514       break;
515     }
516 
517     /* Record a pointer to the logger function and its first argument.
518     ** The default is NULL.  Logging is disabled if the function pointer is
519     ** NULL.
520     */
521     case SQLITE_CONFIG_LOG: {
522       /* MSVC is picky about pulling func ptrs from va lists.
523       ** http://support.microsoft.com/kb/47961
524       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
525       */
526       typedef void(*LOGFUNC_t)(void*,int,const char*);
527       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
528       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
529       break;
530     }
531 
532     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
533     ** can be changed at start-time using the
534     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
535     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
536     */
537     case SQLITE_CONFIG_URI: {
538       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
539       ** argument of type int. If non-zero, then URI handling is globally
540       ** enabled. If the parameter is zero, then URI handling is globally
541       ** disabled. */
542       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
543       break;
544     }
545 
546     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
547       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
548       ** option takes a single integer argument which is interpreted as a
549       ** boolean in order to enable or disable the use of covering indices for
550       ** full table scans in the query optimizer. */
551       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
552       break;
553     }
554 
555 #ifdef SQLITE_ENABLE_SQLLOG
556     case SQLITE_CONFIG_SQLLOG: {
557       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
558       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
559       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
560       break;
561     }
562 #endif
563 
564     case SQLITE_CONFIG_MMAP_SIZE: {
565       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
566       ** integer (sqlite3_int64) values that are the default mmap size limit
567       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
568       ** mmap size limit. */
569       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
570       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
571       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
572       ** negative, then that argument is changed to its compile-time default.
573       **
574       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
575       ** silently truncated if necessary so that it does not exceed the
576       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
577       ** compile-time option.
578       */
579       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ) mxMmap = SQLITE_MAX_MMAP_SIZE;
580       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
581       if( szMmap>mxMmap) szMmap = mxMmap;
582       sqlite3GlobalConfig.mxMmap = mxMmap;
583       sqlite3GlobalConfig.szMmap = szMmap;
584       break;
585     }
586 
587 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
588     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
589       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
590       ** unsigned integer value that specifies the maximum size of the created
591       ** heap. */
592       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
593       break;
594     }
595 #endif
596 
597     default: {
598       rc = SQLITE_ERROR;
599       break;
600     }
601   }
602   va_end(ap);
603   return rc;
604 }
605 
606 /*
607 ** Set up the lookaside buffers for a database connection.
608 ** Return SQLITE_OK on success.
609 ** If lookaside is already active, return SQLITE_BUSY.
610 **
611 ** The sz parameter is the number of bytes in each lookaside slot.
612 ** The cnt parameter is the number of slots.  If pStart is NULL the
613 ** space for the lookaside memory is obtained from sqlite3_malloc().
614 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
615 ** the lookaside memory.
616 */
617 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
618   void *pStart;
619   if( db->lookaside.nOut ){
620     return SQLITE_BUSY;
621   }
622   /* Free any existing lookaside buffer for this handle before
623   ** allocating a new one so we don't have to have space for
624   ** both at the same time.
625   */
626   if( db->lookaside.bMalloced ){
627     sqlite3_free(db->lookaside.pStart);
628   }
629   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
630   ** than a pointer to be useful.
631   */
632   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
633   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
634   if( cnt<0 ) cnt = 0;
635   if( sz==0 || cnt==0 ){
636     sz = 0;
637     pStart = 0;
638   }else if( pBuf==0 ){
639     sqlite3BeginBenignMalloc();
640     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
641     sqlite3EndBenignMalloc();
642     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
643   }else{
644     pStart = pBuf;
645   }
646   db->lookaside.pStart = pStart;
647   db->lookaside.pFree = 0;
648   db->lookaside.sz = (u16)sz;
649   if( pStart ){
650     int i;
651     LookasideSlot *p;
652     assert( sz > (int)sizeof(LookasideSlot*) );
653     p = (LookasideSlot*)pStart;
654     for(i=cnt-1; i>=0; i--){
655       p->pNext = db->lookaside.pFree;
656       db->lookaside.pFree = p;
657       p = (LookasideSlot*)&((u8*)p)[sz];
658     }
659     db->lookaside.pEnd = p;
660     db->lookaside.bEnabled = 1;
661     db->lookaside.bMalloced = pBuf==0 ?1:0;
662   }else{
663     db->lookaside.pStart = db;
664     db->lookaside.pEnd = db;
665     db->lookaside.bEnabled = 0;
666     db->lookaside.bMalloced = 0;
667   }
668   return SQLITE_OK;
669 }
670 
671 /*
672 ** Return the mutex associated with a database connection.
673 */
674 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
675 #ifdef SQLITE_ENABLE_API_ARMOR
676   if( !sqlite3SafetyCheckOk(db) ){
677     (void)SQLITE_MISUSE_BKPT;
678     return 0;
679   }
680 #endif
681   return db->mutex;
682 }
683 
684 /*
685 ** Free up as much memory as we can from the given database
686 ** connection.
687 */
688 int sqlite3_db_release_memory(sqlite3 *db){
689   int i;
690 
691 #ifdef SQLITE_ENABLE_API_ARMOR
692   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
693 #endif
694   sqlite3_mutex_enter(db->mutex);
695   sqlite3BtreeEnterAll(db);
696   for(i=0; i<db->nDb; i++){
697     Btree *pBt = db->aDb[i].pBt;
698     if( pBt ){
699       Pager *pPager = sqlite3BtreePager(pBt);
700       sqlite3PagerShrink(pPager);
701     }
702   }
703   sqlite3BtreeLeaveAll(db);
704   sqlite3_mutex_leave(db->mutex);
705   return SQLITE_OK;
706 }
707 
708 /*
709 ** Configuration settings for an individual database connection
710 */
711 int sqlite3_db_config(sqlite3 *db, int op, ...){
712   va_list ap;
713   int rc;
714   va_start(ap, op);
715   switch( op ){
716     case SQLITE_DBCONFIG_LOOKASIDE: {
717       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
718       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
719       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
720       rc = setupLookaside(db, pBuf, sz, cnt);
721       break;
722     }
723     default: {
724       static const struct {
725         int op;      /* The opcode */
726         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
727       } aFlagOp[] = {
728         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
729         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
730       };
731       unsigned int i;
732       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
733       for(i=0; i<ArraySize(aFlagOp); i++){
734         if( aFlagOp[i].op==op ){
735           int onoff = va_arg(ap, int);
736           int *pRes = va_arg(ap, int*);
737           int oldFlags = db->flags;
738           if( onoff>0 ){
739             db->flags |= aFlagOp[i].mask;
740           }else if( onoff==0 ){
741             db->flags &= ~aFlagOp[i].mask;
742           }
743           if( oldFlags!=db->flags ){
744             sqlite3ExpirePreparedStatements(db);
745           }
746           if( pRes ){
747             *pRes = (db->flags & aFlagOp[i].mask)!=0;
748           }
749           rc = SQLITE_OK;
750           break;
751         }
752       }
753       break;
754     }
755   }
756   va_end(ap);
757   return rc;
758 }
759 
760 
761 /*
762 ** Return true if the buffer z[0..n-1] contains all spaces.
763 */
764 static int allSpaces(const char *z, int n){
765   while( n>0 && z[n-1]==' ' ){ n--; }
766   return n==0;
767 }
768 
769 /*
770 ** This is the default collating function named "BINARY" which is always
771 ** available.
772 **
773 ** If the padFlag argument is not NULL then space padding at the end
774 ** of strings is ignored.  This implements the RTRIM collation.
775 */
776 static int binCollFunc(
777   void *padFlag,
778   int nKey1, const void *pKey1,
779   int nKey2, const void *pKey2
780 ){
781   int rc, n;
782   n = nKey1<nKey2 ? nKey1 : nKey2;
783   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
784   ** strings byte by byte using the memcmp() function from the standard C
785   ** library. */
786   rc = memcmp(pKey1, pKey2, n);
787   if( rc==0 ){
788     if( padFlag
789      && allSpaces(((char*)pKey1)+n, nKey1-n)
790      && allSpaces(((char*)pKey2)+n, nKey2-n)
791     ){
792       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
793       ** spaces at the end of either string do not change the result. In other
794       ** words, strings will compare equal to one another as long as they
795       ** differ only in the number of spaces at the end.
796       */
797     }else{
798       rc = nKey1 - nKey2;
799     }
800   }
801   return rc;
802 }
803 
804 /*
805 ** Another built-in collating sequence: NOCASE.
806 **
807 ** This collating sequence is intended to be used for "case independent
808 ** comparison". SQLite's knowledge of upper and lower case equivalents
809 ** extends only to the 26 characters used in the English language.
810 **
811 ** At the moment there is only a UTF-8 implementation.
812 */
813 static int nocaseCollatingFunc(
814   void *NotUsed,
815   int nKey1, const void *pKey1,
816   int nKey2, const void *pKey2
817 ){
818   int r = sqlite3StrNICmp(
819       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
820   UNUSED_PARAMETER(NotUsed);
821   if( 0==r ){
822     r = nKey1-nKey2;
823   }
824   return r;
825 }
826 
827 /*
828 ** Return the ROWID of the most recent insert
829 */
830 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
831 #ifdef SQLITE_ENABLE_API_ARMOR
832   if( !sqlite3SafetyCheckOk(db) ){
833     (void)SQLITE_MISUSE_BKPT;
834     return 0;
835   }
836 #endif
837   return db->lastRowid;
838 }
839 
840 /*
841 ** Return the number of changes in the most recent call to sqlite3_exec().
842 */
843 int sqlite3_changes(sqlite3 *db){
844 #ifdef SQLITE_ENABLE_API_ARMOR
845   if( !sqlite3SafetyCheckOk(db) ){
846     (void)SQLITE_MISUSE_BKPT;
847     return 0;
848   }
849 #endif
850   return db->nChange;
851 }
852 
853 /*
854 ** Return the number of changes since the database handle was opened.
855 */
856 int sqlite3_total_changes(sqlite3 *db){
857 #ifdef SQLITE_ENABLE_API_ARMOR
858   if( !sqlite3SafetyCheckOk(db) ){
859     (void)SQLITE_MISUSE_BKPT;
860     return 0;
861   }
862 #endif
863   return db->nTotalChange;
864 }
865 
866 /*
867 ** Close all open savepoints. This function only manipulates fields of the
868 ** database handle object, it does not close any savepoints that may be open
869 ** at the b-tree/pager level.
870 */
871 void sqlite3CloseSavepoints(sqlite3 *db){
872   while( db->pSavepoint ){
873     Savepoint *pTmp = db->pSavepoint;
874     db->pSavepoint = pTmp->pNext;
875     sqlite3DbFree(db, pTmp);
876   }
877   db->nSavepoint = 0;
878   db->nStatement = 0;
879   db->isTransactionSavepoint = 0;
880 }
881 
882 /*
883 ** Invoke the destructor function associated with FuncDef p, if any. Except,
884 ** if this is not the last copy of the function, do not invoke it. Multiple
885 ** copies of a single function are created when create_function() is called
886 ** with SQLITE_ANY as the encoding.
887 */
888 static void functionDestroy(sqlite3 *db, FuncDef *p){
889   FuncDestructor *pDestructor = p->pDestructor;
890   if( pDestructor ){
891     pDestructor->nRef--;
892     if( pDestructor->nRef==0 ){
893       pDestructor->xDestroy(pDestructor->pUserData);
894       sqlite3DbFree(db, pDestructor);
895     }
896   }
897 }
898 
899 /*
900 ** Disconnect all sqlite3_vtab objects that belong to database connection
901 ** db. This is called when db is being closed.
902 */
903 static void disconnectAllVtab(sqlite3 *db){
904 #ifndef SQLITE_OMIT_VIRTUALTABLE
905   int i;
906   sqlite3BtreeEnterAll(db);
907   for(i=0; i<db->nDb; i++){
908     Schema *pSchema = db->aDb[i].pSchema;
909     if( db->aDb[i].pSchema ){
910       HashElem *p;
911       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
912         Table *pTab = (Table *)sqliteHashData(p);
913         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
914       }
915     }
916   }
917   sqlite3VtabUnlockList(db);
918   sqlite3BtreeLeaveAll(db);
919 #else
920   UNUSED_PARAMETER(db);
921 #endif
922 }
923 
924 /*
925 ** Return TRUE if database connection db has unfinalized prepared
926 ** statements or unfinished sqlite3_backup objects.
927 */
928 static int connectionIsBusy(sqlite3 *db){
929   int j;
930   assert( sqlite3_mutex_held(db->mutex) );
931   if( db->pVdbe ) return 1;
932   for(j=0; j<db->nDb; j++){
933     Btree *pBt = db->aDb[j].pBt;
934     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
935   }
936   return 0;
937 }
938 
939 /*
940 ** Close an existing SQLite database
941 */
942 static int sqlite3Close(sqlite3 *db, int forceZombie){
943   if( !db ){
944     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
945     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
946     return SQLITE_OK;
947   }
948   if( !sqlite3SafetyCheckSickOrOk(db) ){
949     return SQLITE_MISUSE_BKPT;
950   }
951   sqlite3_mutex_enter(db->mutex);
952 
953   /* Force xDisconnect calls on all virtual tables */
954   disconnectAllVtab(db);
955 
956   /* If a transaction is open, the disconnectAllVtab() call above
957   ** will not have called the xDisconnect() method on any virtual
958   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
959   ** call will do so. We need to do this before the check for active
960   ** SQL statements below, as the v-table implementation may be storing
961   ** some prepared statements internally.
962   */
963   sqlite3VtabRollback(db);
964 
965   /* Legacy behavior (sqlite3_close() behavior) is to return
966   ** SQLITE_BUSY if the connection can not be closed immediately.
967   */
968   if( !forceZombie && connectionIsBusy(db) ){
969     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
970        "statements or unfinished backups");
971     sqlite3_mutex_leave(db->mutex);
972     return SQLITE_BUSY;
973   }
974 
975 #ifdef SQLITE_ENABLE_SQLLOG
976   if( sqlite3GlobalConfig.xSqllog ){
977     /* Closing the handle. Fourth parameter is passed the value 2. */
978     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
979   }
980 #endif
981 
982   /* Convert the connection into a zombie and then close it.
983   */
984   db->magic = SQLITE_MAGIC_ZOMBIE;
985   sqlite3LeaveMutexAndCloseZombie(db);
986   return SQLITE_OK;
987 }
988 
989 /*
990 ** Two variations on the public interface for closing a database
991 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
992 ** leaves the connection option if there are unfinalized prepared
993 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
994 ** version forces the connection to become a zombie if there are
995 ** unclosed resources, and arranges for deallocation when the last
996 ** prepare statement or sqlite3_backup closes.
997 */
998 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
999 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1000 
1001 
1002 /*
1003 ** Close the mutex on database connection db.
1004 **
1005 ** Furthermore, if database connection db is a zombie (meaning that there
1006 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1007 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1008 ** finished, then free all resources.
1009 */
1010 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1011   HashElem *i;                    /* Hash table iterator */
1012   int j;
1013 
1014   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1015   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1016   ** then just leave the mutex and return.
1017   */
1018   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1019     sqlite3_mutex_leave(db->mutex);
1020     return;
1021   }
1022 
1023   /* If we reach this point, it means that the database connection has
1024   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1025   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1026   ** go ahead and free all resources.
1027   */
1028 
1029   /* If a transaction is open, roll it back. This also ensures that if
1030   ** any database schemas have been modified by an uncommitted transaction
1031   ** they are reset. And that the required b-tree mutex is held to make
1032   ** the pager rollback and schema reset an atomic operation. */
1033   sqlite3RollbackAll(db, SQLITE_OK);
1034 
1035   /* Free any outstanding Savepoint structures. */
1036   sqlite3CloseSavepoints(db);
1037 
1038   /* Close all database connections */
1039   for(j=0; j<db->nDb; j++){
1040     struct Db *pDb = &db->aDb[j];
1041     if( pDb->pBt ){
1042       sqlite3BtreeClose(pDb->pBt);
1043       pDb->pBt = 0;
1044       if( j!=1 ){
1045         pDb->pSchema = 0;
1046       }
1047     }
1048   }
1049   /* Clear the TEMP schema separately and last */
1050   if( db->aDb[1].pSchema ){
1051     sqlite3SchemaClear(db->aDb[1].pSchema);
1052   }
1053   sqlite3VtabUnlockList(db);
1054 
1055   /* Free up the array of auxiliary databases */
1056   sqlite3CollapseDatabaseArray(db);
1057   assert( db->nDb<=2 );
1058   assert( db->aDb==db->aDbStatic );
1059 
1060   /* Tell the code in notify.c that the connection no longer holds any
1061   ** locks and does not require any further unlock-notify callbacks.
1062   */
1063   sqlite3ConnectionClosed(db);
1064 
1065   for(j=0; j<ArraySize(db->aFunc.a); j++){
1066     FuncDef *pNext, *pHash, *p;
1067     for(p=db->aFunc.a[j]; p; p=pHash){
1068       pHash = p->pHash;
1069       while( p ){
1070         functionDestroy(db, p);
1071         pNext = p->pNext;
1072         sqlite3DbFree(db, p);
1073         p = pNext;
1074       }
1075     }
1076   }
1077   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1078     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1079     /* Invoke any destructors registered for collation sequence user data. */
1080     for(j=0; j<3; j++){
1081       if( pColl[j].xDel ){
1082         pColl[j].xDel(pColl[j].pUser);
1083       }
1084     }
1085     sqlite3DbFree(db, pColl);
1086   }
1087   sqlite3HashClear(&db->aCollSeq);
1088 #ifndef SQLITE_OMIT_VIRTUALTABLE
1089   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1090     Module *pMod = (Module *)sqliteHashData(i);
1091     if( pMod->xDestroy ){
1092       pMod->xDestroy(pMod->pAux);
1093     }
1094     sqlite3DbFree(db, pMod);
1095   }
1096   sqlite3HashClear(&db->aModule);
1097 #endif
1098 
1099   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1100   sqlite3ValueFree(db->pErr);
1101   sqlite3CloseExtensions(db);
1102 #if SQLITE_USER_AUTHENTICATION
1103   sqlite3_free(db->auth.zAuthUser);
1104   sqlite3_free(db->auth.zAuthPW);
1105 #endif
1106 
1107   db->magic = SQLITE_MAGIC_ERROR;
1108 
1109   /* The temp-database schema is allocated differently from the other schema
1110   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1111   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1112   ** the same sqliteMalloc() as the one that allocates the database
1113   ** structure?
1114   */
1115   sqlite3DbFree(db, db->aDb[1].pSchema);
1116   sqlite3_mutex_leave(db->mutex);
1117   db->magic = SQLITE_MAGIC_CLOSED;
1118   sqlite3_mutex_free(db->mutex);
1119   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1120   if( db->lookaside.bMalloced ){
1121     sqlite3_free(db->lookaside.pStart);
1122   }
1123   sqlite3_free(db);
1124 }
1125 
1126 /*
1127 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1128 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1129 ** breaker") and made to return tripCode if there are any further
1130 ** attempts to use that cursor.  Read cursors remain open and valid
1131 ** but are "saved" in case the table pages are moved around.
1132 */
1133 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1134   int i;
1135   int inTrans = 0;
1136   int schemaChange;
1137   assert( sqlite3_mutex_held(db->mutex) );
1138   sqlite3BeginBenignMalloc();
1139 
1140   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1141   ** This is important in case the transaction being rolled back has
1142   ** modified the database schema. If the b-tree mutexes are not taken
1143   ** here, then another shared-cache connection might sneak in between
1144   ** the database rollback and schema reset, which can cause false
1145   ** corruption reports in some cases.  */
1146   sqlite3BtreeEnterAll(db);
1147   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1148 
1149   for(i=0; i<db->nDb; i++){
1150     Btree *p = db->aDb[i].pBt;
1151     if( p ){
1152       if( sqlite3BtreeIsInTrans(p) ){
1153         inTrans = 1;
1154       }
1155       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1156     }
1157   }
1158   sqlite3VtabRollback(db);
1159   sqlite3EndBenignMalloc();
1160 
1161   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1162     sqlite3ExpirePreparedStatements(db);
1163     sqlite3ResetAllSchemasOfConnection(db);
1164   }
1165   sqlite3BtreeLeaveAll(db);
1166 
1167   /* Any deferred constraint violations have now been resolved. */
1168   db->nDeferredCons = 0;
1169   db->nDeferredImmCons = 0;
1170   db->flags &= ~SQLITE_DeferFKs;
1171 
1172   /* If one has been configured, invoke the rollback-hook callback */
1173   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1174     db->xRollbackCallback(db->pRollbackArg);
1175   }
1176 }
1177 
1178 /*
1179 ** Return a static string containing the name corresponding to the error code
1180 ** specified in the argument.
1181 */
1182 #if (defined(SQLITE_DEBUG) && SQLITE_OS_WIN) || defined(SQLITE_TEST)
1183 const char *sqlite3ErrName(int rc){
1184   const char *zName = 0;
1185   int i, origRc = rc;
1186   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1187     switch( rc ){
1188       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1189       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1190       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1191       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1192       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1193       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1194       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1195       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1196       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1197       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1198       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1199       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1200       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1201       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1202       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1203       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1204       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1205       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1206       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1207       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1208       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1209       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1210       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1211       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1212       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1213       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1214       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1215       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1216       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1217       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1218       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1219       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1220                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1221       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1222       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1223       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1224       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1225       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1226       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1227       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1228       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1229       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1230       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1231       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1232       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1233       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1234       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1235       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1236       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1237       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1238       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1239       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1240       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1241       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1242       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1243       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1244       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1245       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1246       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1247       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1248       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1249       case SQLITE_CONSTRAINT_FOREIGNKEY:
1250                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1251       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1252       case SQLITE_CONSTRAINT_PRIMARYKEY:
1253                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1254       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1255       case SQLITE_CONSTRAINT_COMMITHOOK:
1256                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1257       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1258       case SQLITE_CONSTRAINT_FUNCTION:
1259                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1260       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1261       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1262       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1263       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1264       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1265       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1266       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1267       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1268       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1269       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1270       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1271       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1272                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1273       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1274       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1275       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1276     }
1277   }
1278   if( zName==0 ){
1279     static char zBuf[50];
1280     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1281     zName = zBuf;
1282   }
1283   return zName;
1284 }
1285 #endif
1286 
1287 /*
1288 ** Return a static string that describes the kind of error specified in the
1289 ** argument.
1290 */
1291 const char *sqlite3ErrStr(int rc){
1292   static const char* const aMsg[] = {
1293     /* SQLITE_OK          */ "not an error",
1294     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1295     /* SQLITE_INTERNAL    */ 0,
1296     /* SQLITE_PERM        */ "access permission denied",
1297     /* SQLITE_ABORT       */ "callback requested query abort",
1298     /* SQLITE_BUSY        */ "database is locked",
1299     /* SQLITE_LOCKED      */ "database table is locked",
1300     /* SQLITE_NOMEM       */ "out of memory",
1301     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1302     /* SQLITE_INTERRUPT   */ "interrupted",
1303     /* SQLITE_IOERR       */ "disk I/O error",
1304     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1305     /* SQLITE_NOTFOUND    */ "unknown operation",
1306     /* SQLITE_FULL        */ "database or disk is full",
1307     /* SQLITE_CANTOPEN    */ "unable to open database file",
1308     /* SQLITE_PROTOCOL    */ "locking protocol",
1309     /* SQLITE_EMPTY       */ "table contains no data",
1310     /* SQLITE_SCHEMA      */ "database schema has changed",
1311     /* SQLITE_TOOBIG      */ "string or blob too big",
1312     /* SQLITE_CONSTRAINT  */ "constraint failed",
1313     /* SQLITE_MISMATCH    */ "datatype mismatch",
1314     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1315     /* SQLITE_NOLFS       */ "large file support is disabled",
1316     /* SQLITE_AUTH        */ "authorization denied",
1317     /* SQLITE_FORMAT      */ "auxiliary database format error",
1318     /* SQLITE_RANGE       */ "bind or column index out of range",
1319     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1320   };
1321   const char *zErr = "unknown error";
1322   switch( rc ){
1323     case SQLITE_ABORT_ROLLBACK: {
1324       zErr = "abort due to ROLLBACK";
1325       break;
1326     }
1327     default: {
1328       rc &= 0xff;
1329       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1330         zErr = aMsg[rc];
1331       }
1332       break;
1333     }
1334   }
1335   return zErr;
1336 }
1337 
1338 /*
1339 ** This routine implements a busy callback that sleeps and tries
1340 ** again until a timeout value is reached.  The timeout value is
1341 ** an integer number of milliseconds passed in as the first
1342 ** argument.
1343 */
1344 static int sqliteDefaultBusyCallback(
1345  void *ptr,               /* Database connection */
1346  int count                /* Number of times table has been busy */
1347 ){
1348 #if SQLITE_OS_WIN || (defined(HAVE_USLEEP) && HAVE_USLEEP)
1349   static const u8 delays[] =
1350      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1351   static const u8 totals[] =
1352      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1353 # define NDELAY ArraySize(delays)
1354   sqlite3 *db = (sqlite3 *)ptr;
1355   int timeout = db->busyTimeout;
1356   int delay, prior;
1357 
1358   assert( count>=0 );
1359   if( count < NDELAY ){
1360     delay = delays[count];
1361     prior = totals[count];
1362   }else{
1363     delay = delays[NDELAY-1];
1364     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1365   }
1366   if( prior + delay > timeout ){
1367     delay = timeout - prior;
1368     if( delay<=0 ) return 0;
1369   }
1370   sqlite3OsSleep(db->pVfs, delay*1000);
1371   return 1;
1372 #else
1373   sqlite3 *db = (sqlite3 *)ptr;
1374   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1375   if( (count+1)*1000 > timeout ){
1376     return 0;
1377   }
1378   sqlite3OsSleep(db->pVfs, 1000000);
1379   return 1;
1380 #endif
1381 }
1382 
1383 /*
1384 ** Invoke the given busy handler.
1385 **
1386 ** This routine is called when an operation failed with a lock.
1387 ** If this routine returns non-zero, the lock is retried.  If it
1388 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1389 */
1390 int sqlite3InvokeBusyHandler(BusyHandler *p){
1391   int rc;
1392   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1393   rc = p->xFunc(p->pArg, p->nBusy);
1394   if( rc==0 ){
1395     p->nBusy = -1;
1396   }else{
1397     p->nBusy++;
1398   }
1399   return rc;
1400 }
1401 
1402 /*
1403 ** This routine sets the busy callback for an Sqlite database to the
1404 ** given callback function with the given argument.
1405 */
1406 int sqlite3_busy_handler(
1407   sqlite3 *db,
1408   int (*xBusy)(void*,int),
1409   void *pArg
1410 ){
1411 #ifdef SQLITE_ENABLE_API_ARMOR
1412   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE;
1413 #endif
1414   sqlite3_mutex_enter(db->mutex);
1415   db->busyHandler.xFunc = xBusy;
1416   db->busyHandler.pArg = pArg;
1417   db->busyHandler.nBusy = 0;
1418   db->busyTimeout = 0;
1419   sqlite3_mutex_leave(db->mutex);
1420   return SQLITE_OK;
1421 }
1422 
1423 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1424 /*
1425 ** This routine sets the progress callback for an Sqlite database to the
1426 ** given callback function with the given argument. The progress callback will
1427 ** be invoked every nOps opcodes.
1428 */
1429 void sqlite3_progress_handler(
1430   sqlite3 *db,
1431   int nOps,
1432   int (*xProgress)(void*),
1433   void *pArg
1434 ){
1435 #ifdef SQLITE_ENABLE_API_ARMOR
1436   if( !sqlite3SafetyCheckOk(db) ){
1437     (void)SQLITE_MISUSE_BKPT;
1438     return;
1439   }
1440 #endif
1441   sqlite3_mutex_enter(db->mutex);
1442   if( nOps>0 ){
1443     db->xProgress = xProgress;
1444     db->nProgressOps = (unsigned)nOps;
1445     db->pProgressArg = pArg;
1446   }else{
1447     db->xProgress = 0;
1448     db->nProgressOps = 0;
1449     db->pProgressArg = 0;
1450   }
1451   sqlite3_mutex_leave(db->mutex);
1452 }
1453 #endif
1454 
1455 
1456 /*
1457 ** This routine installs a default busy handler that waits for the
1458 ** specified number of milliseconds before returning 0.
1459 */
1460 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1461 #ifdef SQLITE_ENABLE_API_ARMOR
1462   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1463 #endif
1464   if( ms>0 ){
1465     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1466     db->busyTimeout = ms;
1467   }else{
1468     sqlite3_busy_handler(db, 0, 0);
1469   }
1470   return SQLITE_OK;
1471 }
1472 
1473 /*
1474 ** Cause any pending operation to stop at its earliest opportunity.
1475 */
1476 void sqlite3_interrupt(sqlite3 *db){
1477 #ifdef SQLITE_ENABLE_API_ARMOR
1478   if( !sqlite3SafetyCheckOk(db) ){
1479     (void)SQLITE_MISUSE_BKPT;
1480     return;
1481   }
1482 #endif
1483   db->u1.isInterrupted = 1;
1484 }
1485 
1486 
1487 /*
1488 ** This function is exactly the same as sqlite3_create_function(), except
1489 ** that it is designed to be called by internal code. The difference is
1490 ** that if a malloc() fails in sqlite3_create_function(), an error code
1491 ** is returned and the mallocFailed flag cleared.
1492 */
1493 int sqlite3CreateFunc(
1494   sqlite3 *db,
1495   const char *zFunctionName,
1496   int nArg,
1497   int enc,
1498   void *pUserData,
1499   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1500   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1501   void (*xFinal)(sqlite3_context*),
1502   FuncDestructor *pDestructor
1503 ){
1504   FuncDef *p;
1505   int nName;
1506   int extraFlags;
1507 
1508   assert( sqlite3_mutex_held(db->mutex) );
1509   if( zFunctionName==0 ||
1510       (xFunc && (xFinal || xStep)) ||
1511       (!xFunc && (xFinal && !xStep)) ||
1512       (!xFunc && (!xFinal && xStep)) ||
1513       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1514       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1515     return SQLITE_MISUSE_BKPT;
1516   }
1517 
1518   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1519   extraFlags = enc &  SQLITE_DETERMINISTIC;
1520   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1521 
1522 #ifndef SQLITE_OMIT_UTF16
1523   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1524   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1525   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1526   **
1527   ** If SQLITE_ANY is specified, add three versions of the function
1528   ** to the hash table.
1529   */
1530   if( enc==SQLITE_UTF16 ){
1531     enc = SQLITE_UTF16NATIVE;
1532   }else if( enc==SQLITE_ANY ){
1533     int rc;
1534     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1535          pUserData, xFunc, xStep, xFinal, pDestructor);
1536     if( rc==SQLITE_OK ){
1537       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1538           pUserData, xFunc, xStep, xFinal, pDestructor);
1539     }
1540     if( rc!=SQLITE_OK ){
1541       return rc;
1542     }
1543     enc = SQLITE_UTF16BE;
1544   }
1545 #else
1546   enc = SQLITE_UTF8;
1547 #endif
1548 
1549   /* Check if an existing function is being overridden or deleted. If so,
1550   ** and there are active VMs, then return SQLITE_BUSY. If a function
1551   ** is being overridden/deleted but there are no active VMs, allow the
1552   ** operation to continue but invalidate all precompiled statements.
1553   */
1554   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 0);
1555   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1556     if( db->nVdbeActive ){
1557       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1558         "unable to delete/modify user-function due to active statements");
1559       assert( !db->mallocFailed );
1560       return SQLITE_BUSY;
1561     }else{
1562       sqlite3ExpirePreparedStatements(db);
1563     }
1564   }
1565 
1566   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 1);
1567   assert(p || db->mallocFailed);
1568   if( !p ){
1569     return SQLITE_NOMEM;
1570   }
1571 
1572   /* If an older version of the function with a configured destructor is
1573   ** being replaced invoke the destructor function here. */
1574   functionDestroy(db, p);
1575 
1576   if( pDestructor ){
1577     pDestructor->nRef++;
1578   }
1579   p->pDestructor = pDestructor;
1580   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1581   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1582   p->xFunc = xFunc;
1583   p->xStep = xStep;
1584   p->xFinalize = xFinal;
1585   p->pUserData = pUserData;
1586   p->nArg = (u16)nArg;
1587   return SQLITE_OK;
1588 }
1589 
1590 /*
1591 ** Create new user functions.
1592 */
1593 int sqlite3_create_function(
1594   sqlite3 *db,
1595   const char *zFunc,
1596   int nArg,
1597   int enc,
1598   void *p,
1599   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1600   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1601   void (*xFinal)(sqlite3_context*)
1602 ){
1603   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xFunc, xStep,
1604                                     xFinal, 0);
1605 }
1606 
1607 int sqlite3_create_function_v2(
1608   sqlite3 *db,
1609   const char *zFunc,
1610   int nArg,
1611   int enc,
1612   void *p,
1613   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1614   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1615   void (*xFinal)(sqlite3_context*),
1616   void (*xDestroy)(void *)
1617 ){
1618   int rc = SQLITE_ERROR;
1619   FuncDestructor *pArg = 0;
1620 
1621 #ifdef SQLITE_ENABLE_API_ARMOR
1622   if( !sqlite3SafetyCheckOk(db) ){
1623     return SQLITE_MISUSE_BKPT;
1624   }
1625 #endif
1626   sqlite3_mutex_enter(db->mutex);
1627   if( xDestroy ){
1628     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1629     if( !pArg ){
1630       xDestroy(p);
1631       goto out;
1632     }
1633     pArg->xDestroy = xDestroy;
1634     pArg->pUserData = p;
1635   }
1636   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, pArg);
1637   if( pArg && pArg->nRef==0 ){
1638     assert( rc!=SQLITE_OK );
1639     xDestroy(p);
1640     sqlite3DbFree(db, pArg);
1641   }
1642 
1643  out:
1644   rc = sqlite3ApiExit(db, rc);
1645   sqlite3_mutex_leave(db->mutex);
1646   return rc;
1647 }
1648 
1649 #ifndef SQLITE_OMIT_UTF16
1650 int sqlite3_create_function16(
1651   sqlite3 *db,
1652   const void *zFunctionName,
1653   int nArg,
1654   int eTextRep,
1655   void *p,
1656   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
1657   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1658   void (*xFinal)(sqlite3_context*)
1659 ){
1660   int rc;
1661   char *zFunc8;
1662 
1663 #ifdef SQLITE_ENABLE_API_ARMOR
1664   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1665 #endif
1666   sqlite3_mutex_enter(db->mutex);
1667   assert( !db->mallocFailed );
1668   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1669   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
1670   sqlite3DbFree(db, zFunc8);
1671   rc = sqlite3ApiExit(db, rc);
1672   sqlite3_mutex_leave(db->mutex);
1673   return rc;
1674 }
1675 #endif
1676 
1677 
1678 /*
1679 ** Declare that a function has been overloaded by a virtual table.
1680 **
1681 ** If the function already exists as a regular global function, then
1682 ** this routine is a no-op.  If the function does not exist, then create
1683 ** a new one that always throws a run-time error.
1684 **
1685 ** When virtual tables intend to provide an overloaded function, they
1686 ** should call this routine to make sure the global function exists.
1687 ** A global function must exist in order for name resolution to work
1688 ** properly.
1689 */
1690 int sqlite3_overload_function(
1691   sqlite3 *db,
1692   const char *zName,
1693   int nArg
1694 ){
1695   int nName = sqlite3Strlen30(zName);
1696   int rc = SQLITE_OK;
1697 
1698 #ifdef SQLITE_ENABLE_API_ARMOR
1699   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1700     return SQLITE_MISUSE_BKPT;
1701   }
1702 #endif
1703   sqlite3_mutex_enter(db->mutex);
1704   if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
1705     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1706                            0, sqlite3InvalidFunction, 0, 0, 0);
1707   }
1708   rc = sqlite3ApiExit(db, rc);
1709   sqlite3_mutex_leave(db->mutex);
1710   return rc;
1711 }
1712 
1713 #ifndef SQLITE_OMIT_TRACE
1714 /*
1715 ** Register a trace function.  The pArg from the previously registered trace
1716 ** is returned.
1717 **
1718 ** A NULL trace function means that no tracing is executes.  A non-NULL
1719 ** trace is a pointer to a function that is invoked at the start of each
1720 ** SQL statement.
1721 */
1722 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1723   void *pOld;
1724 
1725 #ifdef SQLITE_ENABLE_API_ARMOR
1726   if( !sqlite3SafetyCheckOk(db) ){
1727     (void)SQLITE_MISUSE_BKPT;
1728     return 0;
1729   }
1730 #endif
1731   sqlite3_mutex_enter(db->mutex);
1732   pOld = db->pTraceArg;
1733   db->xTrace = xTrace;
1734   db->pTraceArg = pArg;
1735   sqlite3_mutex_leave(db->mutex);
1736   return pOld;
1737 }
1738 /*
1739 ** Register a profile function.  The pArg from the previously registered
1740 ** profile function is returned.
1741 **
1742 ** A NULL profile function means that no profiling is executes.  A non-NULL
1743 ** profile is a pointer to a function that is invoked at the conclusion of
1744 ** each SQL statement that is run.
1745 */
1746 void *sqlite3_profile(
1747   sqlite3 *db,
1748   void (*xProfile)(void*,const char*,sqlite_uint64),
1749   void *pArg
1750 ){
1751   void *pOld;
1752 
1753 #ifdef SQLITE_ENABLE_API_ARMOR
1754   if( !sqlite3SafetyCheckOk(db) ){
1755     (void)SQLITE_MISUSE_BKPT;
1756     return 0;
1757   }
1758 #endif
1759   sqlite3_mutex_enter(db->mutex);
1760   pOld = db->pProfileArg;
1761   db->xProfile = xProfile;
1762   db->pProfileArg = pArg;
1763   sqlite3_mutex_leave(db->mutex);
1764   return pOld;
1765 }
1766 #endif /* SQLITE_OMIT_TRACE */
1767 
1768 /*
1769 ** Register a function to be invoked when a transaction commits.
1770 ** If the invoked function returns non-zero, then the commit becomes a
1771 ** rollback.
1772 */
1773 void *sqlite3_commit_hook(
1774   sqlite3 *db,              /* Attach the hook to this database */
1775   int (*xCallback)(void*),  /* Function to invoke on each commit */
1776   void *pArg                /* Argument to the function */
1777 ){
1778   void *pOld;
1779 
1780 #ifdef SQLITE_ENABLE_API_ARMOR
1781   if( !sqlite3SafetyCheckOk(db) ){
1782     (void)SQLITE_MISUSE_BKPT;
1783     return 0;
1784   }
1785 #endif
1786   sqlite3_mutex_enter(db->mutex);
1787   pOld = db->pCommitArg;
1788   db->xCommitCallback = xCallback;
1789   db->pCommitArg = pArg;
1790   sqlite3_mutex_leave(db->mutex);
1791   return pOld;
1792 }
1793 
1794 /*
1795 ** Register a callback to be invoked each time a row is updated,
1796 ** inserted or deleted using this database connection.
1797 */
1798 void *sqlite3_update_hook(
1799   sqlite3 *db,              /* Attach the hook to this database */
1800   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1801   void *pArg                /* Argument to the function */
1802 ){
1803   void *pRet;
1804 
1805 #ifdef SQLITE_ENABLE_API_ARMOR
1806   if( !sqlite3SafetyCheckOk(db) ){
1807     (void)SQLITE_MISUSE_BKPT;
1808     return 0;
1809   }
1810 #endif
1811   sqlite3_mutex_enter(db->mutex);
1812   pRet = db->pUpdateArg;
1813   db->xUpdateCallback = xCallback;
1814   db->pUpdateArg = pArg;
1815   sqlite3_mutex_leave(db->mutex);
1816   return pRet;
1817 }
1818 
1819 /*
1820 ** Register a callback to be invoked each time a transaction is rolled
1821 ** back by this database connection.
1822 */
1823 void *sqlite3_rollback_hook(
1824   sqlite3 *db,              /* Attach the hook to this database */
1825   void (*xCallback)(void*), /* Callback function */
1826   void *pArg                /* Argument to the function */
1827 ){
1828   void *pRet;
1829 
1830 #ifdef SQLITE_ENABLE_API_ARMOR
1831   if( !sqlite3SafetyCheckOk(db) ){
1832     (void)SQLITE_MISUSE_BKPT;
1833     return 0;
1834   }
1835 #endif
1836   sqlite3_mutex_enter(db->mutex);
1837   pRet = db->pRollbackArg;
1838   db->xRollbackCallback = xCallback;
1839   db->pRollbackArg = pArg;
1840   sqlite3_mutex_leave(db->mutex);
1841   return pRet;
1842 }
1843 
1844 #ifndef SQLITE_OMIT_WAL
1845 /*
1846 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1847 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1848 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1849 ** wal_autocheckpoint()).
1850 */
1851 int sqlite3WalDefaultHook(
1852   void *pClientData,     /* Argument */
1853   sqlite3 *db,           /* Connection */
1854   const char *zDb,       /* Database */
1855   int nFrame             /* Size of WAL */
1856 ){
1857   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1858     sqlite3BeginBenignMalloc();
1859     sqlite3_wal_checkpoint(db, zDb);
1860     sqlite3EndBenignMalloc();
1861   }
1862   return SQLITE_OK;
1863 }
1864 #endif /* SQLITE_OMIT_WAL */
1865 
1866 /*
1867 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1868 ** a database after committing a transaction if there are nFrame or
1869 ** more frames in the log file. Passing zero or a negative value as the
1870 ** nFrame parameter disables automatic checkpoints entirely.
1871 **
1872 ** The callback registered by this function replaces any existing callback
1873 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1874 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1875 ** configured by this function.
1876 */
1877 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1878 #ifdef SQLITE_OMIT_WAL
1879   UNUSED_PARAMETER(db);
1880   UNUSED_PARAMETER(nFrame);
1881 #else
1882 #ifdef SQLITE_ENABLE_API_ARMOR
1883   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1884 #endif
1885   if( nFrame>0 ){
1886     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1887   }else{
1888     sqlite3_wal_hook(db, 0, 0);
1889   }
1890 #endif
1891   return SQLITE_OK;
1892 }
1893 
1894 /*
1895 ** Register a callback to be invoked each time a transaction is written
1896 ** into the write-ahead-log by this database connection.
1897 */
1898 void *sqlite3_wal_hook(
1899   sqlite3 *db,                    /* Attach the hook to this db handle */
1900   int(*xCallback)(void *, sqlite3*, const char*, int),
1901   void *pArg                      /* First argument passed to xCallback() */
1902 ){
1903 #ifndef SQLITE_OMIT_WAL
1904   void *pRet;
1905 #ifdef SQLITE_ENABLE_API_ARMOR
1906   if( !sqlite3SafetyCheckOk(db) ){
1907     (void)SQLITE_MISUSE_BKPT;
1908     return 0;
1909   }
1910 #endif
1911   sqlite3_mutex_enter(db->mutex);
1912   pRet = db->pWalArg;
1913   db->xWalCallback = xCallback;
1914   db->pWalArg = pArg;
1915   sqlite3_mutex_leave(db->mutex);
1916   return pRet;
1917 #else
1918   return 0;
1919 #endif
1920 }
1921 
1922 /*
1923 ** Checkpoint database zDb.
1924 */
1925 int sqlite3_wal_checkpoint_v2(
1926   sqlite3 *db,                    /* Database handle */
1927   const char *zDb,                /* Name of attached database (or NULL) */
1928   int eMode,                      /* SQLITE_CHECKPOINT_* value */
1929   int *pnLog,                     /* OUT: Size of WAL log in frames */
1930   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
1931 ){
1932 #ifdef SQLITE_OMIT_WAL
1933   return SQLITE_OK;
1934 #else
1935   int rc;                         /* Return code */
1936   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
1937 
1938 #ifdef SQLITE_ENABLE_API_ARMOR
1939   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1940 #endif
1941 
1942   /* Initialize the output variables to -1 in case an error occurs. */
1943   if( pnLog ) *pnLog = -1;
1944   if( pnCkpt ) *pnCkpt = -1;
1945 
1946   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
1947   assert( SQLITE_CHECKPOINT_FULL==1 );
1948   assert( SQLITE_CHECKPOINT_RESTART==2 );
1949   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
1950   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
1951     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
1952     ** mode: */
1953     return SQLITE_MISUSE;
1954   }
1955 
1956   sqlite3_mutex_enter(db->mutex);
1957   if( zDb && zDb[0] ){
1958     iDb = sqlite3FindDbName(db, zDb);
1959   }
1960   if( iDb<0 ){
1961     rc = SQLITE_ERROR;
1962     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
1963   }else{
1964     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
1965     sqlite3Error(db, rc);
1966   }
1967   rc = sqlite3ApiExit(db, rc);
1968   sqlite3_mutex_leave(db->mutex);
1969   return rc;
1970 #endif
1971 }
1972 
1973 
1974 /*
1975 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
1976 ** to contains a zero-length string, all attached databases are
1977 ** checkpointed.
1978 */
1979 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
1980   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
1981   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
1982   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
1983 }
1984 
1985 #ifndef SQLITE_OMIT_WAL
1986 /*
1987 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
1988 ** not currently open in WAL mode.
1989 **
1990 ** If a transaction is open on the database being checkpointed, this
1991 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
1992 ** an error occurs while running the checkpoint, an SQLite error code is
1993 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
1994 **
1995 ** The mutex on database handle db should be held by the caller. The mutex
1996 ** associated with the specific b-tree being checkpointed is taken by
1997 ** this function while the checkpoint is running.
1998 **
1999 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2000 ** checkpointed. If an error is encountered it is returned immediately -
2001 ** no attempt is made to checkpoint any remaining databases.
2002 **
2003 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2004 */
2005 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2006   int rc = SQLITE_OK;             /* Return code */
2007   int i;                          /* Used to iterate through attached dbs */
2008   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2009 
2010   assert( sqlite3_mutex_held(db->mutex) );
2011   assert( !pnLog || *pnLog==-1 );
2012   assert( !pnCkpt || *pnCkpt==-1 );
2013 
2014   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2015     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2016       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2017       pnLog = 0;
2018       pnCkpt = 0;
2019       if( rc==SQLITE_BUSY ){
2020         bBusy = 1;
2021         rc = SQLITE_OK;
2022       }
2023     }
2024   }
2025 
2026   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2027 }
2028 #endif /* SQLITE_OMIT_WAL */
2029 
2030 /*
2031 ** This function returns true if main-memory should be used instead of
2032 ** a temporary file for transient pager files and statement journals.
2033 ** The value returned depends on the value of db->temp_store (runtime
2034 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2035 ** following table describes the relationship between these two values
2036 ** and this functions return value.
2037 **
2038 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2039 **   -----------------     --------------     ------------------------------
2040 **   0                     any                file      (return 0)
2041 **   1                     1                  file      (return 0)
2042 **   1                     2                  memory    (return 1)
2043 **   1                     0                  file      (return 0)
2044 **   2                     1                  file      (return 0)
2045 **   2                     2                  memory    (return 1)
2046 **   2                     0                  memory    (return 1)
2047 **   3                     any                memory    (return 1)
2048 */
2049 int sqlite3TempInMemory(const sqlite3 *db){
2050 #if SQLITE_TEMP_STORE==1
2051   return ( db->temp_store==2 );
2052 #endif
2053 #if SQLITE_TEMP_STORE==2
2054   return ( db->temp_store!=1 );
2055 #endif
2056 #if SQLITE_TEMP_STORE==3
2057   return 1;
2058 #endif
2059 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2060   return 0;
2061 #endif
2062 }
2063 
2064 /*
2065 ** Return UTF-8 encoded English language explanation of the most recent
2066 ** error.
2067 */
2068 const char *sqlite3_errmsg(sqlite3 *db){
2069   const char *z;
2070   if( !db ){
2071     return sqlite3ErrStr(SQLITE_NOMEM);
2072   }
2073   if( !sqlite3SafetyCheckSickOrOk(db) ){
2074     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2075   }
2076   sqlite3_mutex_enter(db->mutex);
2077   if( db->mallocFailed ){
2078     z = sqlite3ErrStr(SQLITE_NOMEM);
2079   }else{
2080     testcase( db->pErr==0 );
2081     z = (char*)sqlite3_value_text(db->pErr);
2082     assert( !db->mallocFailed );
2083     if( z==0 ){
2084       z = sqlite3ErrStr(db->errCode);
2085     }
2086   }
2087   sqlite3_mutex_leave(db->mutex);
2088   return z;
2089 }
2090 
2091 #ifndef SQLITE_OMIT_UTF16
2092 /*
2093 ** Return UTF-16 encoded English language explanation of the most recent
2094 ** error.
2095 */
2096 const void *sqlite3_errmsg16(sqlite3 *db){
2097   static const u16 outOfMem[] = {
2098     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2099   };
2100   static const u16 misuse[] = {
2101     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2102     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2103     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2104     'o', 'u', 't', ' ',
2105     'o', 'f', ' ',
2106     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2107   };
2108 
2109   const void *z;
2110   if( !db ){
2111     return (void *)outOfMem;
2112   }
2113   if( !sqlite3SafetyCheckSickOrOk(db) ){
2114     return (void *)misuse;
2115   }
2116   sqlite3_mutex_enter(db->mutex);
2117   if( db->mallocFailed ){
2118     z = (void *)outOfMem;
2119   }else{
2120     z = sqlite3_value_text16(db->pErr);
2121     if( z==0 ){
2122       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2123       z = sqlite3_value_text16(db->pErr);
2124     }
2125     /* A malloc() may have failed within the call to sqlite3_value_text16()
2126     ** above. If this is the case, then the db->mallocFailed flag needs to
2127     ** be cleared before returning. Do this directly, instead of via
2128     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2129     */
2130     db->mallocFailed = 0;
2131   }
2132   sqlite3_mutex_leave(db->mutex);
2133   return z;
2134 }
2135 #endif /* SQLITE_OMIT_UTF16 */
2136 
2137 /*
2138 ** Return the most recent error code generated by an SQLite routine. If NULL is
2139 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2140 */
2141 int sqlite3_errcode(sqlite3 *db){
2142   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2143     return SQLITE_MISUSE_BKPT;
2144   }
2145   if( !db || db->mallocFailed ){
2146     return SQLITE_NOMEM;
2147   }
2148   return db->errCode & db->errMask;
2149 }
2150 int sqlite3_extended_errcode(sqlite3 *db){
2151   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2152     return SQLITE_MISUSE_BKPT;
2153   }
2154   if( !db || db->mallocFailed ){
2155     return SQLITE_NOMEM;
2156   }
2157   return db->errCode;
2158 }
2159 
2160 /*
2161 ** Return a string that describes the kind of error specified in the
2162 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2163 ** function.
2164 */
2165 const char *sqlite3_errstr(int rc){
2166   return sqlite3ErrStr(rc);
2167 }
2168 
2169 /*
2170 ** Create a new collating function for database "db".  The name is zName
2171 ** and the encoding is enc.
2172 */
2173 static int createCollation(
2174   sqlite3* db,
2175   const char *zName,
2176   u8 enc,
2177   void* pCtx,
2178   int(*xCompare)(void*,int,const void*,int,const void*),
2179   void(*xDel)(void*)
2180 ){
2181   CollSeq *pColl;
2182   int enc2;
2183 
2184   assert( sqlite3_mutex_held(db->mutex) );
2185 
2186   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2187   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2188   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2189   */
2190   enc2 = enc;
2191   testcase( enc2==SQLITE_UTF16 );
2192   testcase( enc2==SQLITE_UTF16_ALIGNED );
2193   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2194     enc2 = SQLITE_UTF16NATIVE;
2195   }
2196   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2197     return SQLITE_MISUSE_BKPT;
2198   }
2199 
2200   /* Check if this call is removing or replacing an existing collation
2201   ** sequence. If so, and there are active VMs, return busy. If there
2202   ** are no active VMs, invalidate any pre-compiled statements.
2203   */
2204   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2205   if( pColl && pColl->xCmp ){
2206     if( db->nVdbeActive ){
2207       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2208         "unable to delete/modify collation sequence due to active statements");
2209       return SQLITE_BUSY;
2210     }
2211     sqlite3ExpirePreparedStatements(db);
2212 
2213     /* If collation sequence pColl was created directly by a call to
2214     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2215     ** then any copies made by synthCollSeq() need to be invalidated.
2216     ** Also, collation destructor - CollSeq.xDel() - function may need
2217     ** to be called.
2218     */
2219     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2220       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2221       int j;
2222       for(j=0; j<3; j++){
2223         CollSeq *p = &aColl[j];
2224         if( p->enc==pColl->enc ){
2225           if( p->xDel ){
2226             p->xDel(p->pUser);
2227           }
2228           p->xCmp = 0;
2229         }
2230       }
2231     }
2232   }
2233 
2234   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2235   if( pColl==0 ) return SQLITE_NOMEM;
2236   pColl->xCmp = xCompare;
2237   pColl->pUser = pCtx;
2238   pColl->xDel = xDel;
2239   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2240   sqlite3Error(db, SQLITE_OK);
2241   return SQLITE_OK;
2242 }
2243 
2244 
2245 /*
2246 ** This array defines hard upper bounds on limit values.  The
2247 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2248 ** #defines in sqlite3.h.
2249 */
2250 static const int aHardLimit[] = {
2251   SQLITE_MAX_LENGTH,
2252   SQLITE_MAX_SQL_LENGTH,
2253   SQLITE_MAX_COLUMN,
2254   SQLITE_MAX_EXPR_DEPTH,
2255   SQLITE_MAX_COMPOUND_SELECT,
2256   SQLITE_MAX_VDBE_OP,
2257   SQLITE_MAX_FUNCTION_ARG,
2258   SQLITE_MAX_ATTACHED,
2259   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2260   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2261   SQLITE_MAX_TRIGGER_DEPTH,
2262   SQLITE_MAX_WORKER_THREADS,
2263 };
2264 
2265 /*
2266 ** Make sure the hard limits are set to reasonable values
2267 */
2268 #if SQLITE_MAX_LENGTH<100
2269 # error SQLITE_MAX_LENGTH must be at least 100
2270 #endif
2271 #if SQLITE_MAX_SQL_LENGTH<100
2272 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2273 #endif
2274 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2275 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2276 #endif
2277 #if SQLITE_MAX_COMPOUND_SELECT<2
2278 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2279 #endif
2280 #if SQLITE_MAX_VDBE_OP<40
2281 # error SQLITE_MAX_VDBE_OP must be at least 40
2282 #endif
2283 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
2284 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
2285 #endif
2286 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2287 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2288 #endif
2289 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2290 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2291 #endif
2292 #if SQLITE_MAX_COLUMN>32767
2293 # error SQLITE_MAX_COLUMN must not exceed 32767
2294 #endif
2295 #if SQLITE_MAX_TRIGGER_DEPTH<1
2296 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2297 #endif
2298 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2299 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2300 #endif
2301 
2302 
2303 /*
2304 ** Change the value of a limit.  Report the old value.
2305 ** If an invalid limit index is supplied, report -1.
2306 ** Make no changes but still report the old value if the
2307 ** new limit is negative.
2308 **
2309 ** A new lower limit does not shrink existing constructs.
2310 ** It merely prevents new constructs that exceed the limit
2311 ** from forming.
2312 */
2313 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2314   int oldLimit;
2315 
2316 #ifdef SQLITE_ENABLE_API_ARMOR
2317   if( !sqlite3SafetyCheckOk(db) ){
2318     (void)SQLITE_MISUSE_BKPT;
2319     return -1;
2320   }
2321 #endif
2322 
2323   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2324   ** there is a hard upper bound set at compile-time by a C preprocessor
2325   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2326   ** "_MAX_".)
2327   */
2328   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2329   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2330   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2331   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2332   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2333   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2334   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2335   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2336   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2337                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2338   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2339   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2340   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2341   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2342 
2343 
2344   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2345     return -1;
2346   }
2347   oldLimit = db->aLimit[limitId];
2348   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2349     if( newLimit>aHardLimit[limitId] ){
2350       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2351     }
2352     db->aLimit[limitId] = newLimit;
2353   }
2354   return oldLimit;                     /* IMP: R-53341-35419 */
2355 }
2356 
2357 /*
2358 ** This function is used to parse both URIs and non-URI filenames passed by the
2359 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2360 ** URIs specified as part of ATTACH statements.
2361 **
2362 ** The first argument to this function is the name of the VFS to use (or
2363 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2364 ** query parameter. The second argument contains the URI (or non-URI filename)
2365 ** itself. When this function is called the *pFlags variable should contain
2366 ** the default flags to open the database handle with. The value stored in
2367 ** *pFlags may be updated before returning if the URI filename contains
2368 ** "cache=xxx" or "mode=xxx" query parameters.
2369 **
2370 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2371 ** the VFS that should be used to open the database file. *pzFile is set to
2372 ** point to a buffer containing the name of the file to open. It is the
2373 ** responsibility of the caller to eventually call sqlite3_free() to release
2374 ** this buffer.
2375 **
2376 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2377 ** may be set to point to a buffer containing an English language error
2378 ** message. It is the responsibility of the caller to eventually release
2379 ** this buffer by calling sqlite3_free().
2380 */
2381 int sqlite3ParseUri(
2382   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2383   const char *zUri,               /* Nul-terminated URI to parse */
2384   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2385   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2386   char **pzFile,                  /* OUT: Filename component of URI */
2387   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2388 ){
2389   int rc = SQLITE_OK;
2390   unsigned int flags = *pFlags;
2391   const char *zVfs = zDefaultVfs;
2392   char *zFile;
2393   char c;
2394   int nUri = sqlite3Strlen30(zUri);
2395 
2396   assert( *pzErrMsg==0 );
2397 
2398   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2399             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2400    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2401   ){
2402     char *zOpt;
2403     int eState;                   /* Parser state when parsing URI */
2404     int iIn;                      /* Input character index */
2405     int iOut = 0;                 /* Output character index */
2406     int nByte = nUri+2;           /* Bytes of space to allocate */
2407 
2408     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2409     ** method that there may be extra parameters following the file-name.  */
2410     flags |= SQLITE_OPEN_URI;
2411 
2412     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2413     zFile = sqlite3_malloc(nByte);
2414     if( !zFile ) return SQLITE_NOMEM;
2415 
2416     iIn = 5;
2417 #ifndef SQLITE_ALLOW_URI_AUTHORITY
2418     /* Discard the scheme and authority segments of the URI. */
2419     if( zUri[5]=='/' && zUri[6]=='/' ){
2420       iIn = 7;
2421       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2422       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2423         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2424             iIn-7, &zUri[7]);
2425         rc = SQLITE_ERROR;
2426         goto parse_uri_out;
2427       }
2428     }
2429 #endif
2430 
2431     /* Copy the filename and any query parameters into the zFile buffer.
2432     ** Decode %HH escape codes along the way.
2433     **
2434     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2435     ** on the parsing context. As follows:
2436     **
2437     **   0: Parsing file-name.
2438     **   1: Parsing name section of a name=value query parameter.
2439     **   2: Parsing value section of a name=value query parameter.
2440     */
2441     eState = 0;
2442     while( (c = zUri[iIn])!=0 && c!='#' ){
2443       iIn++;
2444       if( c=='%'
2445        && sqlite3Isxdigit(zUri[iIn])
2446        && sqlite3Isxdigit(zUri[iIn+1])
2447       ){
2448         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2449         octet += sqlite3HexToInt(zUri[iIn++]);
2450 
2451         assert( octet>=0 && octet<256 );
2452         if( octet==0 ){
2453           /* This branch is taken when "%00" appears within the URI. In this
2454           ** case we ignore all text in the remainder of the path, name or
2455           ** value currently being parsed. So ignore the current character
2456           ** and skip to the next "?", "=" or "&", as appropriate. */
2457           while( (c = zUri[iIn])!=0 && c!='#'
2458               && (eState!=0 || c!='?')
2459               && (eState!=1 || (c!='=' && c!='&'))
2460               && (eState!=2 || c!='&')
2461           ){
2462             iIn++;
2463           }
2464           continue;
2465         }
2466         c = octet;
2467       }else if( eState==1 && (c=='&' || c=='=') ){
2468         if( zFile[iOut-1]==0 ){
2469           /* An empty option name. Ignore this option altogether. */
2470           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2471           continue;
2472         }
2473         if( c=='&' ){
2474           zFile[iOut++] = '\0';
2475         }else{
2476           eState = 2;
2477         }
2478         c = 0;
2479       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2480         c = 0;
2481         eState = 1;
2482       }
2483       zFile[iOut++] = c;
2484     }
2485     if( eState==1 ) zFile[iOut++] = '\0';
2486     zFile[iOut++] = '\0';
2487     zFile[iOut++] = '\0';
2488 
2489     /* Check if there were any options specified that should be interpreted
2490     ** here. Options that are interpreted here include "vfs" and those that
2491     ** correspond to flags that may be passed to the sqlite3_open_v2()
2492     ** method. */
2493     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2494     while( zOpt[0] ){
2495       int nOpt = sqlite3Strlen30(zOpt);
2496       char *zVal = &zOpt[nOpt+1];
2497       int nVal = sqlite3Strlen30(zVal);
2498 
2499       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2500         zVfs = zVal;
2501       }else{
2502         struct OpenMode {
2503           const char *z;
2504           int mode;
2505         } *aMode = 0;
2506         char *zModeType = 0;
2507         int mask = 0;
2508         int limit = 0;
2509 
2510         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2511           static struct OpenMode aCacheMode[] = {
2512             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2513             { "private", SQLITE_OPEN_PRIVATECACHE },
2514             { 0, 0 }
2515           };
2516 
2517           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2518           aMode = aCacheMode;
2519           limit = mask;
2520           zModeType = "cache";
2521         }
2522         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2523           static struct OpenMode aOpenMode[] = {
2524             { "ro",  SQLITE_OPEN_READONLY },
2525             { "rw",  SQLITE_OPEN_READWRITE },
2526             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2527             { "memory", SQLITE_OPEN_MEMORY },
2528             { 0, 0 }
2529           };
2530 
2531           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2532                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2533           aMode = aOpenMode;
2534           limit = mask & flags;
2535           zModeType = "access";
2536         }
2537 
2538         if( aMode ){
2539           int i;
2540           int mode = 0;
2541           for(i=0; aMode[i].z; i++){
2542             const char *z = aMode[i].z;
2543             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2544               mode = aMode[i].mode;
2545               break;
2546             }
2547           }
2548           if( mode==0 ){
2549             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2550             rc = SQLITE_ERROR;
2551             goto parse_uri_out;
2552           }
2553           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2554             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2555                                         zModeType, zVal);
2556             rc = SQLITE_PERM;
2557             goto parse_uri_out;
2558           }
2559           flags = (flags & ~mask) | mode;
2560         }
2561       }
2562 
2563       zOpt = &zVal[nVal+1];
2564     }
2565 
2566   }else{
2567     zFile = sqlite3_malloc(nUri+2);
2568     if( !zFile ) return SQLITE_NOMEM;
2569     memcpy(zFile, zUri, nUri);
2570     zFile[nUri] = '\0';
2571     zFile[nUri+1] = '\0';
2572     flags &= ~SQLITE_OPEN_URI;
2573   }
2574 
2575   *ppVfs = sqlite3_vfs_find(zVfs);
2576   if( *ppVfs==0 ){
2577     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2578     rc = SQLITE_ERROR;
2579   }
2580  parse_uri_out:
2581   if( rc!=SQLITE_OK ){
2582     sqlite3_free(zFile);
2583     zFile = 0;
2584   }
2585   *pFlags = flags;
2586   *pzFile = zFile;
2587   return rc;
2588 }
2589 
2590 
2591 /*
2592 ** This routine does the work of opening a database on behalf of
2593 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2594 ** is UTF-8 encoded.
2595 */
2596 static int openDatabase(
2597   const char *zFilename, /* Database filename UTF-8 encoded */
2598   sqlite3 **ppDb,        /* OUT: Returned database handle */
2599   unsigned int flags,    /* Operational flags */
2600   const char *zVfs       /* Name of the VFS to use */
2601 ){
2602   sqlite3 *db;                    /* Store allocated handle here */
2603   int rc;                         /* Return code */
2604   int isThreadsafe;               /* True for threadsafe connections */
2605   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2606   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2607 
2608 #ifdef SQLITE_ENABLE_API_ARMOR
2609   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2610 #endif
2611   *ppDb = 0;
2612 #ifndef SQLITE_OMIT_AUTOINIT
2613   rc = sqlite3_initialize();
2614   if( rc ) return rc;
2615 #endif
2616 
2617   /* Only allow sensible combinations of bits in the flags argument.
2618   ** Throw an error if any non-sense combination is used.  If we
2619   ** do not block illegal combinations here, it could trigger
2620   ** assert() statements in deeper layers.  Sensible combinations
2621   ** are:
2622   **
2623   **  1:  SQLITE_OPEN_READONLY
2624   **  2:  SQLITE_OPEN_READWRITE
2625   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2626   */
2627   assert( SQLITE_OPEN_READONLY  == 0x01 );
2628   assert( SQLITE_OPEN_READWRITE == 0x02 );
2629   assert( SQLITE_OPEN_CREATE    == 0x04 );
2630   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2631   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2632   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2633   if( ((1<<(flags&7)) & 0x46)==0 ){
2634     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2635   }
2636 
2637   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2638     isThreadsafe = 0;
2639   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2640     isThreadsafe = 0;
2641   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2642     isThreadsafe = 1;
2643   }else{
2644     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2645   }
2646   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2647     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2648   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2649     flags |= SQLITE_OPEN_SHAREDCACHE;
2650   }
2651 
2652   /* Remove harmful bits from the flags parameter
2653   **
2654   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2655   ** dealt with in the previous code block.  Besides these, the only
2656   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2657   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2658   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2659   ** off all other flags.
2660   */
2661   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2662                SQLITE_OPEN_EXCLUSIVE |
2663                SQLITE_OPEN_MAIN_DB |
2664                SQLITE_OPEN_TEMP_DB |
2665                SQLITE_OPEN_TRANSIENT_DB |
2666                SQLITE_OPEN_MAIN_JOURNAL |
2667                SQLITE_OPEN_TEMP_JOURNAL |
2668                SQLITE_OPEN_SUBJOURNAL |
2669                SQLITE_OPEN_MASTER_JOURNAL |
2670                SQLITE_OPEN_NOMUTEX |
2671                SQLITE_OPEN_FULLMUTEX |
2672                SQLITE_OPEN_WAL
2673              );
2674 
2675   /* Allocate the sqlite data structure */
2676   db = sqlite3MallocZero( sizeof(sqlite3) );
2677   if( db==0 ) goto opendb_out;
2678   if( isThreadsafe ){
2679     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2680     if( db->mutex==0 ){
2681       sqlite3_free(db);
2682       db = 0;
2683       goto opendb_out;
2684     }
2685   }
2686   sqlite3_mutex_enter(db->mutex);
2687   db->errMask = 0xff;
2688   db->nDb = 2;
2689   db->magic = SQLITE_MAGIC_BUSY;
2690   db->aDb = db->aDbStatic;
2691 
2692   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2693   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2694   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2695   db->autoCommit = 1;
2696   db->nextAutovac = -1;
2697   db->szMmap = sqlite3GlobalConfig.szMmap;
2698   db->nextPagesize = 0;
2699   db->nMaxSorterMmap = 0x7FFFFFFF;
2700   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2701 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2702                  | SQLITE_AutoIndex
2703 #endif
2704 #if SQLITE_DEFAULT_FILE_FORMAT<4
2705                  | SQLITE_LegacyFileFmt
2706 #endif
2707 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2708                  | SQLITE_LoadExtension
2709 #endif
2710 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2711                  | SQLITE_RecTriggers
2712 #endif
2713 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2714                  | SQLITE_ForeignKeys
2715 #endif
2716 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2717                  | SQLITE_ReverseOrder
2718 #endif
2719       ;
2720   sqlite3HashInit(&db->aCollSeq);
2721 #ifndef SQLITE_OMIT_VIRTUALTABLE
2722   sqlite3HashInit(&db->aModule);
2723 #endif
2724 
2725   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2726   ** and UTF-16, so add a version for each to avoid any unnecessary
2727   ** conversions. The only error that can occur here is a malloc() failure.
2728   **
2729   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2730   ** functions:
2731   */
2732   createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
2733   createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
2734   createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
2735   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2736   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2737   if( db->mallocFailed ){
2738     goto opendb_out;
2739   }
2740   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2741   ** strings is BINARY.
2742   */
2743   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
2744   assert( db->pDfltColl!=0 );
2745 
2746   /* Parse the filename/URI argument. */
2747   db->openFlags = flags;
2748   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2749   if( rc!=SQLITE_OK ){
2750     if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
2751     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2752     sqlite3_free(zErrMsg);
2753     goto opendb_out;
2754   }
2755 
2756   /* Open the backend database driver */
2757   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2758                         flags | SQLITE_OPEN_MAIN_DB);
2759   if( rc!=SQLITE_OK ){
2760     if( rc==SQLITE_IOERR_NOMEM ){
2761       rc = SQLITE_NOMEM;
2762     }
2763     sqlite3Error(db, rc);
2764     goto opendb_out;
2765   }
2766   sqlite3BtreeEnter(db->aDb[0].pBt);
2767   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2768   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2769   sqlite3BtreeLeave(db->aDb[0].pBt);
2770   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2771 
2772   /* The default safety_level for the main database is 'full'; for the temp
2773   ** database it is 'NONE'. This matches the pager layer defaults.
2774   */
2775   db->aDb[0].zName = "main";
2776   db->aDb[0].safety_level = 3;
2777   db->aDb[1].zName = "temp";
2778   db->aDb[1].safety_level = 1;
2779 
2780   db->magic = SQLITE_MAGIC_OPEN;
2781   if( db->mallocFailed ){
2782     goto opendb_out;
2783   }
2784 
2785   /* Register all built-in functions, but do not attempt to read the
2786   ** database schema yet. This is delayed until the first time the database
2787   ** is accessed.
2788   */
2789   sqlite3Error(db, SQLITE_OK);
2790   sqlite3RegisterBuiltinFunctions(db);
2791 
2792   /* Load automatic extensions - extensions that have been registered
2793   ** using the sqlite3_automatic_extension() API.
2794   */
2795   rc = sqlite3_errcode(db);
2796   if( rc==SQLITE_OK ){
2797     sqlite3AutoLoadExtensions(db);
2798     rc = sqlite3_errcode(db);
2799     if( rc!=SQLITE_OK ){
2800       goto opendb_out;
2801     }
2802   }
2803 
2804 #ifdef SQLITE_ENABLE_FTS1
2805   if( !db->mallocFailed ){
2806     extern int sqlite3Fts1Init(sqlite3*);
2807     rc = sqlite3Fts1Init(db);
2808   }
2809 #endif
2810 
2811 #ifdef SQLITE_ENABLE_FTS2
2812   if( !db->mallocFailed && rc==SQLITE_OK ){
2813     extern int sqlite3Fts2Init(sqlite3*);
2814     rc = sqlite3Fts2Init(db);
2815   }
2816 #endif
2817 
2818 #ifdef SQLITE_ENABLE_FTS3
2819   if( !db->mallocFailed && rc==SQLITE_OK ){
2820     rc = sqlite3Fts3Init(db);
2821   }
2822 #endif
2823 
2824 #ifdef SQLITE_ENABLE_ICU
2825   if( !db->mallocFailed && rc==SQLITE_OK ){
2826     rc = sqlite3IcuInit(db);
2827   }
2828 #endif
2829 
2830 #ifdef SQLITE_ENABLE_RTREE
2831   if( !db->mallocFailed && rc==SQLITE_OK){
2832     rc = sqlite3RtreeInit(db);
2833   }
2834 #endif
2835 
2836   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2837   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2838   ** mode.  Doing nothing at all also makes NORMAL the default.
2839   */
2840 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2841   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2842   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2843                           SQLITE_DEFAULT_LOCKING_MODE);
2844 #endif
2845 
2846   if( rc ) sqlite3Error(db, rc);
2847 
2848   /* Enable the lookaside-malloc subsystem */
2849   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2850                         sqlite3GlobalConfig.nLookaside);
2851 
2852   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2853 
2854 opendb_out:
2855   sqlite3_free(zOpen);
2856   if( db ){
2857     assert( db->mutex!=0 || isThreadsafe==0 || sqlite3GlobalConfig.bFullMutex==0 );
2858     sqlite3_mutex_leave(db->mutex);
2859   }
2860   rc = sqlite3_errcode(db);
2861   assert( db!=0 || rc==SQLITE_NOMEM );
2862   if( rc==SQLITE_NOMEM ){
2863     sqlite3_close(db);
2864     db = 0;
2865   }else if( rc!=SQLITE_OK ){
2866     db->magic = SQLITE_MAGIC_SICK;
2867   }
2868   *ppDb = db;
2869 #ifdef SQLITE_ENABLE_SQLLOG
2870   if( sqlite3GlobalConfig.xSqllog ){
2871     /* Opening a db handle. Fourth parameter is passed 0. */
2872     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2873     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2874   }
2875 #endif
2876   return sqlite3ApiExit(0, rc);
2877 }
2878 
2879 /*
2880 ** Open a new database handle.
2881 */
2882 int sqlite3_open(
2883   const char *zFilename,
2884   sqlite3 **ppDb
2885 ){
2886   return openDatabase(zFilename, ppDb,
2887                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2888 }
2889 int sqlite3_open_v2(
2890   const char *filename,   /* Database filename (UTF-8) */
2891   sqlite3 **ppDb,         /* OUT: SQLite db handle */
2892   int flags,              /* Flags */
2893   const char *zVfs        /* Name of VFS module to use */
2894 ){
2895   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
2896 }
2897 
2898 #ifndef SQLITE_OMIT_UTF16
2899 /*
2900 ** Open a new database handle.
2901 */
2902 int sqlite3_open16(
2903   const void *zFilename,
2904   sqlite3 **ppDb
2905 ){
2906   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
2907   sqlite3_value *pVal;
2908   int rc;
2909 
2910 #ifdef SQLITE_ENABLE_API_ARMOR
2911   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2912 #endif
2913   *ppDb = 0;
2914 #ifndef SQLITE_OMIT_AUTOINIT
2915   rc = sqlite3_initialize();
2916   if( rc ) return rc;
2917 #endif
2918   if( zFilename==0 ) zFilename = "\000\000";
2919   pVal = sqlite3ValueNew(0);
2920   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
2921   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
2922   if( zFilename8 ){
2923     rc = openDatabase(zFilename8, ppDb,
2924                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2925     assert( *ppDb || rc==SQLITE_NOMEM );
2926     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
2927       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
2928     }
2929   }else{
2930     rc = SQLITE_NOMEM;
2931   }
2932   sqlite3ValueFree(pVal);
2933 
2934   return sqlite3ApiExit(0, rc);
2935 }
2936 #endif /* SQLITE_OMIT_UTF16 */
2937 
2938 /*
2939 ** Register a new collation sequence with the database handle db.
2940 */
2941 int sqlite3_create_collation(
2942   sqlite3* db,
2943   const char *zName,
2944   int enc,
2945   void* pCtx,
2946   int(*xCompare)(void*,int,const void*,int,const void*)
2947 ){
2948   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
2949 }
2950 
2951 /*
2952 ** Register a new collation sequence with the database handle db.
2953 */
2954 int sqlite3_create_collation_v2(
2955   sqlite3* db,
2956   const char *zName,
2957   int enc,
2958   void* pCtx,
2959   int(*xCompare)(void*,int,const void*,int,const void*),
2960   void(*xDel)(void*)
2961 ){
2962   int rc;
2963 
2964 #ifdef SQLITE_ENABLE_API_ARMOR
2965   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
2966 #endif
2967   sqlite3_mutex_enter(db->mutex);
2968   assert( !db->mallocFailed );
2969   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
2970   rc = sqlite3ApiExit(db, rc);
2971   sqlite3_mutex_leave(db->mutex);
2972   return rc;
2973 }
2974 
2975 #ifndef SQLITE_OMIT_UTF16
2976 /*
2977 ** Register a new collation sequence with the database handle db.
2978 */
2979 int sqlite3_create_collation16(
2980   sqlite3* db,
2981   const void *zName,
2982   int enc,
2983   void* pCtx,
2984   int(*xCompare)(void*,int,const void*,int,const void*)
2985 ){
2986   int rc = SQLITE_OK;
2987   char *zName8;
2988 
2989 #ifdef SQLITE_ENABLE_API_ARMOR
2990   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
2991 #endif
2992   sqlite3_mutex_enter(db->mutex);
2993   assert( !db->mallocFailed );
2994   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
2995   if( zName8 ){
2996     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
2997     sqlite3DbFree(db, zName8);
2998   }
2999   rc = sqlite3ApiExit(db, rc);
3000   sqlite3_mutex_leave(db->mutex);
3001   return rc;
3002 }
3003 #endif /* SQLITE_OMIT_UTF16 */
3004 
3005 /*
3006 ** Register a collation sequence factory callback with the database handle
3007 ** db. Replace any previously installed collation sequence factory.
3008 */
3009 int sqlite3_collation_needed(
3010   sqlite3 *db,
3011   void *pCollNeededArg,
3012   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3013 ){
3014 #ifdef SQLITE_ENABLE_API_ARMOR
3015   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3016 #endif
3017   sqlite3_mutex_enter(db->mutex);
3018   db->xCollNeeded = xCollNeeded;
3019   db->xCollNeeded16 = 0;
3020   db->pCollNeededArg = pCollNeededArg;
3021   sqlite3_mutex_leave(db->mutex);
3022   return SQLITE_OK;
3023 }
3024 
3025 #ifndef SQLITE_OMIT_UTF16
3026 /*
3027 ** Register a collation sequence factory callback with the database handle
3028 ** db. Replace any previously installed collation sequence factory.
3029 */
3030 int sqlite3_collation_needed16(
3031   sqlite3 *db,
3032   void *pCollNeededArg,
3033   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3034 ){
3035 #ifdef SQLITE_ENABLE_API_ARMOR
3036   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3037 #endif
3038   sqlite3_mutex_enter(db->mutex);
3039   db->xCollNeeded = 0;
3040   db->xCollNeeded16 = xCollNeeded16;
3041   db->pCollNeededArg = pCollNeededArg;
3042   sqlite3_mutex_leave(db->mutex);
3043   return SQLITE_OK;
3044 }
3045 #endif /* SQLITE_OMIT_UTF16 */
3046 
3047 #ifndef SQLITE_OMIT_DEPRECATED
3048 /*
3049 ** This function is now an anachronism. It used to be used to recover from a
3050 ** malloc() failure, but SQLite now does this automatically.
3051 */
3052 int sqlite3_global_recover(void){
3053   return SQLITE_OK;
3054 }
3055 #endif
3056 
3057 /*
3058 ** Test to see whether or not the database connection is in autocommit
3059 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3060 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3061 ** by the next COMMIT or ROLLBACK.
3062 */
3063 int sqlite3_get_autocommit(sqlite3 *db){
3064 #ifdef SQLITE_ENABLE_API_ARMOR
3065   if( !sqlite3SafetyCheckOk(db) ){
3066     (void)SQLITE_MISUSE_BKPT;
3067     return 0;
3068   }
3069 #endif
3070   return db->autoCommit;
3071 }
3072 
3073 /*
3074 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3075 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
3076 ** constants.  They serve two purposes:
3077 **
3078 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3079 **       to detect when version error conditions occurs.
3080 **
3081 **   2.  Invoke sqlite3_log() to provide the source code location where
3082 **       a low-level error is first detected.
3083 */
3084 int sqlite3CorruptError(int lineno){
3085   testcase( sqlite3GlobalConfig.xLog!=0 );
3086   sqlite3_log(SQLITE_CORRUPT,
3087               "database corruption at line %d of [%.10s]",
3088               lineno, 20+sqlite3_sourceid());
3089   return SQLITE_CORRUPT;
3090 }
3091 int sqlite3MisuseError(int lineno){
3092   testcase( sqlite3GlobalConfig.xLog!=0 );
3093   sqlite3_log(SQLITE_MISUSE,
3094               "misuse at line %d of [%.10s]",
3095               lineno, 20+sqlite3_sourceid());
3096   return SQLITE_MISUSE;
3097 }
3098 int sqlite3CantopenError(int lineno){
3099   testcase( sqlite3GlobalConfig.xLog!=0 );
3100   sqlite3_log(SQLITE_CANTOPEN,
3101               "cannot open file at line %d of [%.10s]",
3102               lineno, 20+sqlite3_sourceid());
3103   return SQLITE_CANTOPEN;
3104 }
3105 
3106 
3107 #ifndef SQLITE_OMIT_DEPRECATED
3108 /*
3109 ** This is a convenience routine that makes sure that all thread-specific
3110 ** data for this thread has been deallocated.
3111 **
3112 ** SQLite no longer uses thread-specific data so this routine is now a
3113 ** no-op.  It is retained for historical compatibility.
3114 */
3115 void sqlite3_thread_cleanup(void){
3116 }
3117 #endif
3118 
3119 /*
3120 ** Return meta information about a specific column of a database table.
3121 ** See comment in sqlite3.h (sqlite.h.in) for details.
3122 */
3123 int sqlite3_table_column_metadata(
3124   sqlite3 *db,                /* Connection handle */
3125   const char *zDbName,        /* Database name or NULL */
3126   const char *zTableName,     /* Table name */
3127   const char *zColumnName,    /* Column name */
3128   char const **pzDataType,    /* OUTPUT: Declared data type */
3129   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3130   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3131   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3132   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3133 ){
3134   int rc;
3135   char *zErrMsg = 0;
3136   Table *pTab = 0;
3137   Column *pCol = 0;
3138   int iCol;
3139 
3140   char const *zDataType = 0;
3141   char const *zCollSeq = 0;
3142   int notnull = 0;
3143   int primarykey = 0;
3144   int autoinc = 0;
3145 
3146   /* Ensure the database schema has been loaded */
3147   sqlite3_mutex_enter(db->mutex);
3148   sqlite3BtreeEnterAll(db);
3149   rc = sqlite3Init(db, &zErrMsg);
3150   if( SQLITE_OK!=rc ){
3151     goto error_out;
3152   }
3153 
3154   /* Locate the table in question */
3155   pTab = sqlite3FindTable(db, zTableName, zDbName);
3156   if( !pTab || pTab->pSelect ){
3157     pTab = 0;
3158     goto error_out;
3159   }
3160 
3161   /* Find the column for which info is requested */
3162   if( zColumnName==0 ){
3163     /* Query for existance of table only */
3164   }else{
3165     for(iCol=0; iCol<pTab->nCol; iCol++){
3166       pCol = &pTab->aCol[iCol];
3167       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3168         break;
3169       }
3170     }
3171     if( iCol==pTab->nCol ){
3172       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3173         iCol = pTab->iPKey;
3174         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3175       }else{
3176         pTab = 0;
3177         goto error_out;
3178       }
3179     }
3180   }
3181 
3182   /* The following block stores the meta information that will be returned
3183   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3184   ** and autoinc. At this point there are two possibilities:
3185   **
3186   **     1. The specified column name was rowid", "oid" or "_rowid_"
3187   **        and there is no explicitly declared IPK column.
3188   **
3189   **     2. The table is not a view and the column name identified an
3190   **        explicitly declared column. Copy meta information from *pCol.
3191   */
3192   if( pCol ){
3193     zDataType = pCol->zType;
3194     zCollSeq = pCol->zColl;
3195     notnull = pCol->notNull!=0;
3196     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3197     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3198   }else{
3199     zDataType = "INTEGER";
3200     primarykey = 1;
3201   }
3202   if( !zCollSeq ){
3203     zCollSeq = "BINARY";
3204   }
3205 
3206 error_out:
3207   sqlite3BtreeLeaveAll(db);
3208 
3209   /* Whether the function call succeeded or failed, set the output parameters
3210   ** to whatever their local counterparts contain. If an error did occur,
3211   ** this has the effect of zeroing all output parameters.
3212   */
3213   if( pzDataType ) *pzDataType = zDataType;
3214   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3215   if( pNotNull ) *pNotNull = notnull;
3216   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3217   if( pAutoinc ) *pAutoinc = autoinc;
3218 
3219   if( SQLITE_OK==rc && !pTab ){
3220     sqlite3DbFree(db, zErrMsg);
3221     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3222         zColumnName);
3223     rc = SQLITE_ERROR;
3224   }
3225   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3226   sqlite3DbFree(db, zErrMsg);
3227   rc = sqlite3ApiExit(db, rc);
3228   sqlite3_mutex_leave(db->mutex);
3229   return rc;
3230 }
3231 
3232 /*
3233 ** Sleep for a little while.  Return the amount of time slept.
3234 */
3235 int sqlite3_sleep(int ms){
3236   sqlite3_vfs *pVfs;
3237   int rc;
3238   pVfs = sqlite3_vfs_find(0);
3239   if( pVfs==0 ) return 0;
3240 
3241   /* This function works in milliseconds, but the underlying OsSleep()
3242   ** API uses microseconds. Hence the 1000's.
3243   */
3244   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3245   return rc;
3246 }
3247 
3248 /*
3249 ** Enable or disable the extended result codes.
3250 */
3251 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3252 #ifdef SQLITE_ENABLE_API_ARMOR
3253   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3254 #endif
3255   sqlite3_mutex_enter(db->mutex);
3256   db->errMask = onoff ? 0xffffffff : 0xff;
3257   sqlite3_mutex_leave(db->mutex);
3258   return SQLITE_OK;
3259 }
3260 
3261 /*
3262 ** Invoke the xFileControl method on a particular database.
3263 */
3264 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3265   int rc = SQLITE_ERROR;
3266   Btree *pBtree;
3267 
3268 #ifdef SQLITE_ENABLE_API_ARMOR
3269   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3270 #endif
3271   sqlite3_mutex_enter(db->mutex);
3272   pBtree = sqlite3DbNameToBtree(db, zDbName);
3273   if( pBtree ){
3274     Pager *pPager;
3275     sqlite3_file *fd;
3276     sqlite3BtreeEnter(pBtree);
3277     pPager = sqlite3BtreePager(pBtree);
3278     assert( pPager!=0 );
3279     fd = sqlite3PagerFile(pPager);
3280     assert( fd!=0 );
3281     if( op==SQLITE_FCNTL_FILE_POINTER ){
3282       *(sqlite3_file**)pArg = fd;
3283       rc = SQLITE_OK;
3284     }else if( fd->pMethods ){
3285       rc = sqlite3OsFileControl(fd, op, pArg);
3286     }else{
3287       rc = SQLITE_NOTFOUND;
3288     }
3289     sqlite3BtreeLeave(pBtree);
3290   }
3291   sqlite3_mutex_leave(db->mutex);
3292   return rc;
3293 }
3294 
3295 /*
3296 ** Interface to the testing logic.
3297 */
3298 int sqlite3_test_control(int op, ...){
3299   int rc = 0;
3300 #ifndef SQLITE_OMIT_BUILTIN_TEST
3301   va_list ap;
3302   va_start(ap, op);
3303   switch( op ){
3304 
3305     /*
3306     ** Save the current state of the PRNG.
3307     */
3308     case SQLITE_TESTCTRL_PRNG_SAVE: {
3309       sqlite3PrngSaveState();
3310       break;
3311     }
3312 
3313     /*
3314     ** Restore the state of the PRNG to the last state saved using
3315     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3316     ** this verb acts like PRNG_RESET.
3317     */
3318     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3319       sqlite3PrngRestoreState();
3320       break;
3321     }
3322 
3323     /*
3324     ** Reset the PRNG back to its uninitialized state.  The next call
3325     ** to sqlite3_randomness() will reseed the PRNG using a single call
3326     ** to the xRandomness method of the default VFS.
3327     */
3328     case SQLITE_TESTCTRL_PRNG_RESET: {
3329       sqlite3_randomness(0,0);
3330       break;
3331     }
3332 
3333     /*
3334     **  sqlite3_test_control(BITVEC_TEST, size, program)
3335     **
3336     ** Run a test against a Bitvec object of size.  The program argument
3337     ** is an array of integers that defines the test.  Return -1 on a
3338     ** memory allocation error, 0 on success, or non-zero for an error.
3339     ** See the sqlite3BitvecBuiltinTest() for additional information.
3340     */
3341     case SQLITE_TESTCTRL_BITVEC_TEST: {
3342       int sz = va_arg(ap, int);
3343       int *aProg = va_arg(ap, int*);
3344       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3345       break;
3346     }
3347 
3348     /*
3349     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3350     **
3351     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3352     ** if xCallback is not NULL.
3353     **
3354     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3355     ** is called immediately after installing the new callback and the return
3356     ** value from sqlite3FaultSim(0) becomes the return from
3357     ** sqlite3_test_control().
3358     */
3359     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3360       /* MSVC is picky about pulling func ptrs from va lists.
3361       ** http://support.microsoft.com/kb/47961
3362       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3363       */
3364       typedef int(*TESTCALLBACKFUNC_t)(int);
3365       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3366       rc = sqlite3FaultSim(0);
3367       break;
3368     }
3369 
3370     /*
3371     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3372     **
3373     ** Register hooks to call to indicate which malloc() failures
3374     ** are benign.
3375     */
3376     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3377       typedef void (*void_function)(void);
3378       void_function xBenignBegin;
3379       void_function xBenignEnd;
3380       xBenignBegin = va_arg(ap, void_function);
3381       xBenignEnd = va_arg(ap, void_function);
3382       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3383       break;
3384     }
3385 
3386     /*
3387     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3388     **
3389     ** Set the PENDING byte to the value in the argument, if X>0.
3390     ** Make no changes if X==0.  Return the value of the pending byte
3391     ** as it existing before this routine was called.
3392     **
3393     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3394     ** an incompatible database file format.  Changing the PENDING byte
3395     ** while any database connection is open results in undefined and
3396     ** deleterious behavior.
3397     */
3398     case SQLITE_TESTCTRL_PENDING_BYTE: {
3399       rc = PENDING_BYTE;
3400 #ifndef SQLITE_OMIT_WSD
3401       {
3402         unsigned int newVal = va_arg(ap, unsigned int);
3403         if( newVal ) sqlite3PendingByte = newVal;
3404       }
3405 #endif
3406       break;
3407     }
3408 
3409     /*
3410     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3411     **
3412     ** This action provides a run-time test to see whether or not
3413     ** assert() was enabled at compile-time.  If X is true and assert()
3414     ** is enabled, then the return value is true.  If X is true and
3415     ** assert() is disabled, then the return value is zero.  If X is
3416     ** false and assert() is enabled, then the assertion fires and the
3417     ** process aborts.  If X is false and assert() is disabled, then the
3418     ** return value is zero.
3419     */
3420     case SQLITE_TESTCTRL_ASSERT: {
3421       volatile int x = 0;
3422       assert( (x = va_arg(ap,int))!=0 );
3423       rc = x;
3424       break;
3425     }
3426 
3427 
3428     /*
3429     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3430     **
3431     ** This action provides a run-time test to see how the ALWAYS and
3432     ** NEVER macros were defined at compile-time.
3433     **
3434     ** The return value is ALWAYS(X).
3435     **
3436     ** The recommended test is X==2.  If the return value is 2, that means
3437     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3438     ** default setting.  If the return value is 1, then ALWAYS() is either
3439     ** hard-coded to true or else it asserts if its argument is false.
3440     ** The first behavior (hard-coded to true) is the case if
3441     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3442     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3443     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3444     **
3445     ** The run-time test procedure might look something like this:
3446     **
3447     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3448     **      // ALWAYS() and NEVER() are no-op pass-through macros
3449     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3450     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3451     **    }else{
3452     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3453     **    }
3454     */
3455     case SQLITE_TESTCTRL_ALWAYS: {
3456       int x = va_arg(ap,int);
3457       rc = ALWAYS(x);
3458       break;
3459     }
3460 
3461     /*
3462     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3463     **
3464     ** The integer returned reveals the byte-order of the computer on which
3465     ** SQLite is running:
3466     **
3467     **       1     big-endian,    determined at run-time
3468     **      10     little-endian, determined at run-time
3469     **  432101     big-endian,    determined at compile-time
3470     **  123410     little-endian, determined at compile-time
3471     */
3472     case SQLITE_TESTCTRL_BYTEORDER: {
3473       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3474       break;
3475     }
3476 
3477     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3478     **
3479     ** Set the nReserve size to N for the main database on the database
3480     ** connection db.
3481     */
3482     case SQLITE_TESTCTRL_RESERVE: {
3483       sqlite3 *db = va_arg(ap, sqlite3*);
3484       int x = va_arg(ap,int);
3485       sqlite3_mutex_enter(db->mutex);
3486       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3487       sqlite3_mutex_leave(db->mutex);
3488       break;
3489     }
3490 
3491     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3492     **
3493     ** Enable or disable various optimizations for testing purposes.  The
3494     ** argument N is a bitmask of optimizations to be disabled.  For normal
3495     ** operation N should be 0.  The idea is that a test program (like the
3496     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3497     ** with various optimizations disabled to verify that the same answer
3498     ** is obtained in every case.
3499     */
3500     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3501       sqlite3 *db = va_arg(ap, sqlite3*);
3502       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3503       break;
3504     }
3505 
3506 #ifdef SQLITE_N_KEYWORD
3507     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3508     **
3509     ** If zWord is a keyword recognized by the parser, then return the
3510     ** number of keywords.  Or if zWord is not a keyword, return 0.
3511     **
3512     ** This test feature is only available in the amalgamation since
3513     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3514     ** is built using separate source files.
3515     */
3516     case SQLITE_TESTCTRL_ISKEYWORD: {
3517       const char *zWord = va_arg(ap, const char*);
3518       int n = sqlite3Strlen30(zWord);
3519       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3520       break;
3521     }
3522 #endif
3523 
3524     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3525     **
3526     ** Pass pFree into sqlite3ScratchFree().
3527     ** If sz>0 then allocate a scratch buffer into pNew.
3528     */
3529     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3530       void *pFree, **ppNew;
3531       int sz;
3532       sz = va_arg(ap, int);
3533       ppNew = va_arg(ap, void**);
3534       pFree = va_arg(ap, void*);
3535       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3536       sqlite3ScratchFree(pFree);
3537       break;
3538     }
3539 
3540     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3541     **
3542     ** If parameter onoff is non-zero, configure the wrappers so that all
3543     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3544     ** undo this setting.
3545     */
3546     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3547       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3548       break;
3549     }
3550 
3551     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3552     **
3553     ** Set or clear a flag that indicates that the database file is always well-
3554     ** formed and never corrupt.  This flag is clear by default, indicating that
3555     ** database files might have arbitrary corruption.  Setting the flag during
3556     ** testing causes certain assert() statements in the code to be activated
3557     ** that demonstrat invariants on well-formed database files.
3558     */
3559     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3560       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3561       break;
3562     }
3563 
3564 
3565     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3566     **
3567     ** Set the VDBE coverage callback function to xCallback with context
3568     ** pointer ptr.
3569     */
3570     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3571 #ifdef SQLITE_VDBE_COVERAGE
3572       typedef void (*branch_callback)(void*,int,u8,u8);
3573       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3574       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3575 #endif
3576       break;
3577     }
3578 
3579     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3580     case SQLITE_TESTCTRL_SORTER_MMAP: {
3581       sqlite3 *db = va_arg(ap, sqlite3*);
3582       db->nMaxSorterMmap = va_arg(ap, int);
3583       break;
3584     }
3585 
3586     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3587     **
3588     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3589     ** not.
3590     */
3591     case SQLITE_TESTCTRL_ISINIT: {
3592       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3593       break;
3594     }
3595   }
3596   va_end(ap);
3597 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3598   return rc;
3599 }
3600 
3601 /*
3602 ** This is a utility routine, useful to VFS implementations, that checks
3603 ** to see if a database file was a URI that contained a specific query
3604 ** parameter, and if so obtains the value of the query parameter.
3605 **
3606 ** The zFilename argument is the filename pointer passed into the xOpen()
3607 ** method of a VFS implementation.  The zParam argument is the name of the
3608 ** query parameter we seek.  This routine returns the value of the zParam
3609 ** parameter if it exists.  If the parameter does not exist, this routine
3610 ** returns a NULL pointer.
3611 */
3612 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3613   if( zFilename==0 || zParam==0 ) return 0;
3614   zFilename += sqlite3Strlen30(zFilename) + 1;
3615   while( zFilename[0] ){
3616     int x = strcmp(zFilename, zParam);
3617     zFilename += sqlite3Strlen30(zFilename) + 1;
3618     if( x==0 ) return zFilename;
3619     zFilename += sqlite3Strlen30(zFilename) + 1;
3620   }
3621   return 0;
3622 }
3623 
3624 /*
3625 ** Return a boolean value for a query parameter.
3626 */
3627 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3628   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3629   bDflt = bDflt!=0;
3630   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3631 }
3632 
3633 /*
3634 ** Return a 64-bit integer value for a query parameter.
3635 */
3636 sqlite3_int64 sqlite3_uri_int64(
3637   const char *zFilename,    /* Filename as passed to xOpen */
3638   const char *zParam,       /* URI parameter sought */
3639   sqlite3_int64 bDflt       /* return if parameter is missing */
3640 ){
3641   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3642   sqlite3_int64 v;
3643   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3644     bDflt = v;
3645   }
3646   return bDflt;
3647 }
3648 
3649 /*
3650 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3651 */
3652 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3653   int i;
3654   for(i=0; i<db->nDb; i++){
3655     if( db->aDb[i].pBt
3656      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3657     ){
3658       return db->aDb[i].pBt;
3659     }
3660   }
3661   return 0;
3662 }
3663 
3664 /*
3665 ** Return the filename of the database associated with a database
3666 ** connection.
3667 */
3668 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3669   Btree *pBt;
3670 #ifdef SQLITE_ENABLE_API_ARMOR
3671   if( !sqlite3SafetyCheckOk(db) ){
3672     (void)SQLITE_MISUSE_BKPT;
3673     return 0;
3674   }
3675 #endif
3676   pBt = sqlite3DbNameToBtree(db, zDbName);
3677   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3678 }
3679 
3680 /*
3681 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3682 ** no such database exists.
3683 */
3684 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3685   Btree *pBt;
3686 #ifdef SQLITE_ENABLE_API_ARMOR
3687   if( !sqlite3SafetyCheckOk(db) ){
3688     (void)SQLITE_MISUSE_BKPT;
3689     return -1;
3690   }
3691 #endif
3692   pBt = sqlite3DbNameToBtree(db, zDbName);
3693   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3694 }
3695