xref: /sqlite-3.40.0/src/main.c (revision 049d487e)
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 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 
121 #ifdef SQLITE_OMIT_WSD
122   rc = sqlite3_wsd_init(4096, 24);
123   if( rc!=SQLITE_OK ){
124     return rc;
125   }
126 #endif
127 
128   /* If SQLite is already completely initialized, then this call
129   ** to sqlite3_initialize() should be a no-op.  But the initialization
130   ** must be complete.  So isInit must not be set until the very end
131   ** of this routine.
132   */
133   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
134 
135 #ifdef SQLITE_ENABLE_SQLLOG
136   {
137     extern void sqlite3_init_sqllog(void);
138     sqlite3_init_sqllog();
139   }
140 #endif
141 
142   /* Make sure the mutex subsystem is initialized.  If unable to
143   ** initialize the mutex subsystem, return early with the error.
144   ** If the system is so sick that we are unable to allocate a mutex,
145   ** there is not much SQLite is going to be able to do.
146   **
147   ** The mutex subsystem must take care of serializing its own
148   ** initialization.
149   */
150   rc = sqlite3MutexInit();
151   if( rc ) return rc;
152 
153   /* Initialize the malloc() system and the recursive pInitMutex mutex.
154   ** This operation is protected by the STATIC_MASTER mutex.  Note that
155   ** MutexAlloc() is called for a static mutex prior to initializing the
156   ** malloc subsystem - this implies that the allocation of a static
157   ** mutex must not require support from the malloc subsystem.
158   */
159   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
160   sqlite3_mutex_enter(pMaster);
161   sqlite3GlobalConfig.isMutexInit = 1;
162   if( !sqlite3GlobalConfig.isMallocInit ){
163     rc = sqlite3MallocInit();
164   }
165   if( rc==SQLITE_OK ){
166     sqlite3GlobalConfig.isMallocInit = 1;
167     if( !sqlite3GlobalConfig.pInitMutex ){
168       sqlite3GlobalConfig.pInitMutex =
169            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
170       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
171         rc = SQLITE_NOMEM;
172       }
173     }
174   }
175   if( rc==SQLITE_OK ){
176     sqlite3GlobalConfig.nRefInitMutex++;
177   }
178   sqlite3_mutex_leave(pMaster);
179 
180   /* If rc is not SQLITE_OK at this point, then either the malloc
181   ** subsystem could not be initialized or the system failed to allocate
182   ** the pInitMutex mutex. Return an error in either case.  */
183   if( rc!=SQLITE_OK ){
184     return rc;
185   }
186 
187   /* Do the rest of the initialization under the recursive mutex so
188   ** that we will be able to handle recursive calls into
189   ** sqlite3_initialize().  The recursive calls normally come through
190   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
191   ** recursive calls might also be possible.
192   **
193   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
194   ** to the xInit method, so the xInit method need not be threadsafe.
195   **
196   ** The following mutex is what serializes access to the appdef pcache xInit
197   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
198   ** call to sqlite3PcacheInitialize().
199   */
200   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
201   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
202     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
203     sqlite3GlobalConfig.inProgress = 1;
204     memset(pHash, 0, sizeof(sqlite3GlobalFunctions));
205     sqlite3RegisterGlobalFunctions();
206     if( sqlite3GlobalConfig.isPCacheInit==0 ){
207       rc = sqlite3PcacheInitialize();
208     }
209     if( rc==SQLITE_OK ){
210       sqlite3GlobalConfig.isPCacheInit = 1;
211       rc = sqlite3OsInit();
212     }
213     if( rc==SQLITE_OK ){
214       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
215           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
216       sqlite3GlobalConfig.isInit = 1;
217     }
218     sqlite3GlobalConfig.inProgress = 0;
219   }
220   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
221 
222   /* Go back under the static mutex and clean up the recursive
223   ** mutex to prevent a resource leak.
224   */
225   sqlite3_mutex_enter(pMaster);
226   sqlite3GlobalConfig.nRefInitMutex--;
227   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
228     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
229     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
230     sqlite3GlobalConfig.pInitMutex = 0;
231   }
232   sqlite3_mutex_leave(pMaster);
233 
234   /* The following is just a sanity check to make sure SQLite has
235   ** been compiled correctly.  It is important to run this code, but
236   ** we don't want to run it too often and soak up CPU cycles for no
237   ** reason.  So we run it once during initialization.
238   */
239 #ifndef NDEBUG
240 #ifndef SQLITE_OMIT_FLOATING_POINT
241   /* This section of code's only "output" is via assert() statements. */
242   if ( rc==SQLITE_OK ){
243     u64 x = (((u64)1)<<63)-1;
244     double y;
245     assert(sizeof(x)==8);
246     assert(sizeof(x)==sizeof(y));
247     memcpy(&y, &x, 8);
248     assert( sqlite3IsNaN(y) );
249   }
250 #endif
251 #endif
252 
253   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
254   ** compile-time option.
255   */
256 #ifdef SQLITE_EXTRA_INIT
257   if( rc==SQLITE_OK && sqlite3GlobalConfig.isInit ){
258     int SQLITE_EXTRA_INIT(const char*);
259     rc = SQLITE_EXTRA_INIT(0);
260   }
261 #endif
262 
263   return rc;
264 }
265 
266 /*
267 ** Undo the effects of sqlite3_initialize().  Must not be called while
268 ** there are outstanding database connections or memory allocations or
269 ** while any part of SQLite is otherwise in use in any thread.  This
270 ** routine is not threadsafe.  But it is safe to invoke this routine
271 ** on when SQLite is already shut down.  If SQLite is already shut down
272 ** when this routine is invoked, then this routine is a harmless no-op.
273 */
274 int sqlite3_shutdown(void){
275   if( sqlite3GlobalConfig.isInit ){
276 #ifdef SQLITE_EXTRA_SHUTDOWN
277     void SQLITE_EXTRA_SHUTDOWN(void);
278     SQLITE_EXTRA_SHUTDOWN();
279 #endif
280     sqlite3_os_end();
281     sqlite3_reset_auto_extension();
282     sqlite3GlobalConfig.isInit = 0;
283   }
284   if( sqlite3GlobalConfig.isPCacheInit ){
285     sqlite3PcacheShutdown();
286     sqlite3GlobalConfig.isPCacheInit = 0;
287   }
288   if( sqlite3GlobalConfig.isMallocInit ){
289     sqlite3MallocEnd();
290     sqlite3GlobalConfig.isMallocInit = 0;
291 
292 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
293     /* The heap subsystem has now been shutdown and these values are supposed
294     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
295     ** which would rely on that heap subsystem; therefore, make sure these
296     ** values cannot refer to heap memory that was just invalidated when the
297     ** heap subsystem was shutdown.  This is only done if the current call to
298     ** this function resulted in the heap subsystem actually being shutdown.
299     */
300     sqlite3_data_directory = 0;
301     sqlite3_temp_directory = 0;
302 #endif
303   }
304   if( sqlite3GlobalConfig.isMutexInit ){
305     sqlite3MutexEnd();
306     sqlite3GlobalConfig.isMutexInit = 0;
307   }
308 
309   return SQLITE_OK;
310 }
311 
312 /*
313 ** This API allows applications to modify the global configuration of
314 ** the SQLite library at run-time.
315 **
316 ** This routine should only be called when there are no outstanding
317 ** database connections or memory allocations.  This routine is not
318 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
319 ** behavior.
320 */
321 int sqlite3_config(int op, ...){
322   va_list ap;
323   int rc = SQLITE_OK;
324 
325   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
326   ** the SQLite library is in use. */
327   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
328 
329   va_start(ap, op);
330   switch( op ){
331 
332     /* Mutex configuration options are only available in a threadsafe
333     ** compile.
334     */
335 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0
336     case SQLITE_CONFIG_SINGLETHREAD: {
337       /* Disable all mutexing */
338       sqlite3GlobalConfig.bCoreMutex = 0;
339       sqlite3GlobalConfig.bFullMutex = 0;
340       break;
341     }
342     case SQLITE_CONFIG_MULTITHREAD: {
343       /* Disable mutexing of database connections */
344       /* Enable mutexing of core data structures */
345       sqlite3GlobalConfig.bCoreMutex = 1;
346       sqlite3GlobalConfig.bFullMutex = 0;
347       break;
348     }
349     case SQLITE_CONFIG_SERIALIZED: {
350       /* Enable all mutexing */
351       sqlite3GlobalConfig.bCoreMutex = 1;
352       sqlite3GlobalConfig.bFullMutex = 1;
353       break;
354     }
355     case SQLITE_CONFIG_MUTEX: {
356       /* Specify an alternative mutex implementation */
357       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
358       break;
359     }
360     case SQLITE_CONFIG_GETMUTEX: {
361       /* Retrieve the current mutex implementation */
362       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
363       break;
364     }
365 #endif
366 
367 
368     case SQLITE_CONFIG_MALLOC: {
369       /* Specify an alternative malloc implementation */
370       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
371       break;
372     }
373     case SQLITE_CONFIG_GETMALLOC: {
374       /* Retrieve the current malloc() implementation */
375       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
376       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
377       break;
378     }
379     case SQLITE_CONFIG_MEMSTATUS: {
380       /* Enable or disable the malloc status collection */
381       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
382       break;
383     }
384     case SQLITE_CONFIG_SCRATCH: {
385       /* Designate a buffer for scratch memory space */
386       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
387       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
388       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
389       break;
390     }
391     case SQLITE_CONFIG_PAGECACHE: {
392       /* Designate a buffer for page cache memory space */
393       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
394       sqlite3GlobalConfig.szPage = va_arg(ap, int);
395       sqlite3GlobalConfig.nPage = va_arg(ap, int);
396       break;
397     }
398 
399     case SQLITE_CONFIG_PCACHE: {
400       /* no-op */
401       break;
402     }
403     case SQLITE_CONFIG_GETPCACHE: {
404       /* now an error */
405       rc = SQLITE_ERROR;
406       break;
407     }
408 
409     case SQLITE_CONFIG_PCACHE2: {
410       /* Specify an alternative page cache implementation */
411       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
412       break;
413     }
414     case SQLITE_CONFIG_GETPCACHE2: {
415       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
416         sqlite3PCacheSetDefault();
417       }
418       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
419       break;
420     }
421 
422 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
423     case SQLITE_CONFIG_HEAP: {
424       /* Designate a buffer for heap memory space */
425       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
426       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
427       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
428 
429       if( sqlite3GlobalConfig.mnReq<1 ){
430         sqlite3GlobalConfig.mnReq = 1;
431       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
432         /* cap min request size at 2^12 */
433         sqlite3GlobalConfig.mnReq = (1<<12);
434       }
435 
436       if( sqlite3GlobalConfig.pHeap==0 ){
437         /* If the heap pointer is NULL, then restore the malloc implementation
438         ** back to NULL pointers too.  This will cause the malloc to go
439         ** back to its default implementation when sqlite3_initialize() is
440         ** run.
441         */
442         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
443       }else{
444         /* The heap pointer is not NULL, then install one of the
445         ** mem5.c/mem3.c methods. If neither ENABLE_MEMSYS3 nor
446         ** ENABLE_MEMSYS5 is defined, return an error.
447         */
448 #ifdef SQLITE_ENABLE_MEMSYS3
449         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
450 #endif
451 #ifdef SQLITE_ENABLE_MEMSYS5
452         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
453 #endif
454       }
455       break;
456     }
457 #endif
458 
459     case SQLITE_CONFIG_LOOKASIDE: {
460       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
461       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
462       break;
463     }
464 
465     /* Record a pointer to the logger funcction and its first argument.
466     ** The default is NULL.  Logging is disabled if the function pointer is
467     ** NULL.
468     */
469     case SQLITE_CONFIG_LOG: {
470       /* MSVC is picky about pulling func ptrs from va lists.
471       ** http://support.microsoft.com/kb/47961
472       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
473       */
474       typedef void(*LOGFUNC_t)(void*,int,const char*);
475       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
476       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
477       break;
478     }
479 
480     case SQLITE_CONFIG_URI: {
481       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
482       break;
483     }
484 
485     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
486       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
487       break;
488     }
489 
490 #ifdef SQLITE_ENABLE_SQLLOG
491     case SQLITE_CONFIG_SQLLOG: {
492       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
493       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
494       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
495       break;
496     }
497 #endif
498 
499     case SQLITE_CONFIG_MMAP_SIZE: {
500       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
501       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
502       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
503         mxMmap = SQLITE_MAX_MMAP_SIZE;
504       }
505       sqlite3GlobalConfig.mxMmap = mxMmap;
506       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
507       if( szMmap>mxMmap) szMmap = mxMmap;
508       sqlite3GlobalConfig.szMmap = szMmap;
509       break;
510     }
511 
512     default: {
513       rc = SQLITE_ERROR;
514       break;
515     }
516   }
517   va_end(ap);
518   return rc;
519 }
520 
521 /*
522 ** Set up the lookaside buffers for a database connection.
523 ** Return SQLITE_OK on success.
524 ** If lookaside is already active, return SQLITE_BUSY.
525 **
526 ** The sz parameter is the number of bytes in each lookaside slot.
527 ** The cnt parameter is the number of slots.  If pStart is NULL the
528 ** space for the lookaside memory is obtained from sqlite3_malloc().
529 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
530 ** the lookaside memory.
531 */
532 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
533   void *pStart;
534   if( db->lookaside.nOut ){
535     return SQLITE_BUSY;
536   }
537   /* Free any existing lookaside buffer for this handle before
538   ** allocating a new one so we don't have to have space for
539   ** both at the same time.
540   */
541   if( db->lookaside.bMalloced ){
542     sqlite3_free(db->lookaside.pStart);
543   }
544   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
545   ** than a pointer to be useful.
546   */
547   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
548   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
549   if( cnt<0 ) cnt = 0;
550   if( sz==0 || cnt==0 ){
551     sz = 0;
552     pStart = 0;
553   }else if( pBuf==0 ){
554     sqlite3BeginBenignMalloc();
555     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
556     sqlite3EndBenignMalloc();
557     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
558   }else{
559     pStart = pBuf;
560   }
561   db->lookaside.pStart = pStart;
562   db->lookaside.pFree = 0;
563   db->lookaside.sz = (u16)sz;
564   if( pStart ){
565     int i;
566     LookasideSlot *p;
567     assert( sz > (int)sizeof(LookasideSlot*) );
568     p = (LookasideSlot*)pStart;
569     for(i=cnt-1; i>=0; i--){
570       p->pNext = db->lookaside.pFree;
571       db->lookaside.pFree = p;
572       p = (LookasideSlot*)&((u8*)p)[sz];
573     }
574     db->lookaside.pEnd = p;
575     db->lookaside.bEnabled = 1;
576     db->lookaside.bMalloced = pBuf==0 ?1:0;
577   }else{
578     db->lookaside.pEnd = 0;
579     db->lookaside.bEnabled = 0;
580     db->lookaside.bMalloced = 0;
581   }
582   return SQLITE_OK;
583 }
584 
585 /*
586 ** Return the mutex associated with a database connection.
587 */
588 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
589   return db->mutex;
590 }
591 
592 /*
593 ** Free up as much memory as we can from the given database
594 ** connection.
595 */
596 int sqlite3_db_release_memory(sqlite3 *db){
597   int i;
598   sqlite3_mutex_enter(db->mutex);
599   sqlite3BtreeEnterAll(db);
600   for(i=0; i<db->nDb; i++){
601     Btree *pBt = db->aDb[i].pBt;
602     if( pBt ){
603       Pager *pPager = sqlite3BtreePager(pBt);
604       sqlite3PagerShrink(pPager);
605     }
606   }
607   sqlite3BtreeLeaveAll(db);
608   sqlite3_mutex_leave(db->mutex);
609   return SQLITE_OK;
610 }
611 
612 /*
613 ** Configuration settings for an individual database connection
614 */
615 int sqlite3_db_config(sqlite3 *db, int op, ...){
616   va_list ap;
617   int rc;
618   va_start(ap, op);
619   switch( op ){
620     case SQLITE_DBCONFIG_LOOKASIDE: {
621       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
622       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
623       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
624       rc = setupLookaside(db, pBuf, sz, cnt);
625       break;
626     }
627     default: {
628       static const struct {
629         int op;      /* The opcode */
630         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
631       } aFlagOp[] = {
632         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
633         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
634       };
635       unsigned int i;
636       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
637       for(i=0; i<ArraySize(aFlagOp); i++){
638         if( aFlagOp[i].op==op ){
639           int onoff = va_arg(ap, int);
640           int *pRes = va_arg(ap, int*);
641           int oldFlags = db->flags;
642           if( onoff>0 ){
643             db->flags |= aFlagOp[i].mask;
644           }else if( onoff==0 ){
645             db->flags &= ~aFlagOp[i].mask;
646           }
647           if( oldFlags!=db->flags ){
648             sqlite3ExpirePreparedStatements(db);
649           }
650           if( pRes ){
651             *pRes = (db->flags & aFlagOp[i].mask)!=0;
652           }
653           rc = SQLITE_OK;
654           break;
655         }
656       }
657       break;
658     }
659   }
660   va_end(ap);
661   return rc;
662 }
663 
664 
665 /*
666 ** Return true if the buffer z[0..n-1] contains all spaces.
667 */
668 static int allSpaces(const char *z, int n){
669   while( n>0 && z[n-1]==' ' ){ n--; }
670   return n==0;
671 }
672 
673 /*
674 ** This is the default collating function named "BINARY" which is always
675 ** available.
676 **
677 ** If the padFlag argument is not NULL then space padding at the end
678 ** of strings is ignored.  This implements the RTRIM collation.
679 */
680 static int binCollFunc(
681   void *padFlag,
682   int nKey1, const void *pKey1,
683   int nKey2, const void *pKey2
684 ){
685   int rc, n;
686   n = nKey1<nKey2 ? nKey1 : nKey2;
687   rc = memcmp(pKey1, pKey2, n);
688   if( rc==0 ){
689     if( padFlag
690      && allSpaces(((char*)pKey1)+n, nKey1-n)
691      && allSpaces(((char*)pKey2)+n, nKey2-n)
692     ){
693       /* Leave rc unchanged at 0 */
694     }else{
695       rc = nKey1 - nKey2;
696     }
697   }
698   return rc;
699 }
700 
701 /*
702 ** Another built-in collating sequence: NOCASE.
703 **
704 ** This collating sequence is intended to be used for "case independent
705 ** comparison". SQLite's knowledge of upper and lower case equivalents
706 ** extends only to the 26 characters used in the English language.
707 **
708 ** At the moment there is only a UTF-8 implementation.
709 */
710 static int nocaseCollatingFunc(
711   void *NotUsed,
712   int nKey1, const void *pKey1,
713   int nKey2, const void *pKey2
714 ){
715   int r = sqlite3StrNICmp(
716       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
717   UNUSED_PARAMETER(NotUsed);
718   if( 0==r ){
719     r = nKey1-nKey2;
720   }
721   return r;
722 }
723 
724 /*
725 ** Return the ROWID of the most recent insert
726 */
727 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
728   return db->lastRowid;
729 }
730 
731 /*
732 ** Return the number of changes in the most recent call to sqlite3_exec().
733 */
734 int sqlite3_changes(sqlite3 *db){
735   return db->nChange;
736 }
737 
738 /*
739 ** Return the number of changes since the database handle was opened.
740 */
741 int sqlite3_total_changes(sqlite3 *db){
742   return db->nTotalChange;
743 }
744 
745 /*
746 ** Close all open savepoints. This function only manipulates fields of the
747 ** database handle object, it does not close any savepoints that may be open
748 ** at the b-tree/pager level.
749 */
750 void sqlite3CloseSavepoints(sqlite3 *db){
751   while( db->pSavepoint ){
752     Savepoint *pTmp = db->pSavepoint;
753     db->pSavepoint = pTmp->pNext;
754     sqlite3DbFree(db, pTmp);
755   }
756   db->nSavepoint = 0;
757   db->nStatement = 0;
758   db->isTransactionSavepoint = 0;
759 }
760 
761 /*
762 ** Invoke the destructor function associated with FuncDef p, if any. Except,
763 ** if this is not the last copy of the function, do not invoke it. Multiple
764 ** copies of a single function are created when create_function() is called
765 ** with SQLITE_ANY as the encoding.
766 */
767 static void functionDestroy(sqlite3 *db, FuncDef *p){
768   FuncDestructor *pDestructor = p->pDestructor;
769   if( pDestructor ){
770     pDestructor->nRef--;
771     if( pDestructor->nRef==0 ){
772       pDestructor->xDestroy(pDestructor->pUserData);
773       sqlite3DbFree(db, pDestructor);
774     }
775   }
776 }
777 
778 /*
779 ** Disconnect all sqlite3_vtab objects that belong to database connection
780 ** db. This is called when db is being closed.
781 */
782 static void disconnectAllVtab(sqlite3 *db){
783 #ifndef SQLITE_OMIT_VIRTUALTABLE
784   int i;
785   sqlite3BtreeEnterAll(db);
786   for(i=0; i<db->nDb; i++){
787     Schema *pSchema = db->aDb[i].pSchema;
788     if( db->aDb[i].pSchema ){
789       HashElem *p;
790       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
791         Table *pTab = (Table *)sqliteHashData(p);
792         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
793       }
794     }
795   }
796   sqlite3BtreeLeaveAll(db);
797 #else
798   UNUSED_PARAMETER(db);
799 #endif
800 }
801 
802 /*
803 ** Return TRUE if database connection db has unfinalized prepared
804 ** statements or unfinished sqlite3_backup objects.
805 */
806 static int connectionIsBusy(sqlite3 *db){
807   int j;
808   assert( sqlite3_mutex_held(db->mutex) );
809   if( db->pVdbe ) return 1;
810   for(j=0; j<db->nDb; j++){
811     Btree *pBt = db->aDb[j].pBt;
812     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
813   }
814   return 0;
815 }
816 
817 /*
818 ** Close an existing SQLite database
819 */
820 static int sqlite3Close(sqlite3 *db, int forceZombie){
821   if( !db ){
822     return SQLITE_OK;
823   }
824   if( !sqlite3SafetyCheckSickOrOk(db) ){
825     return SQLITE_MISUSE_BKPT;
826   }
827   sqlite3_mutex_enter(db->mutex);
828 
829   /* Force xDisconnect calls on all virtual tables */
830   disconnectAllVtab(db);
831 
832   /* If a transaction is open, the disconnectAllVtab() call above
833   ** will not have called the xDisconnect() method on any virtual
834   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
835   ** call will do so. We need to do this before the check for active
836   ** SQL statements below, as the v-table implementation may be storing
837   ** some prepared statements internally.
838   */
839   sqlite3VtabRollback(db);
840 
841   /* Legacy behavior (sqlite3_close() behavior) is to return
842   ** SQLITE_BUSY if the connection can not be closed immediately.
843   */
844   if( !forceZombie && connectionIsBusy(db) ){
845     sqlite3Error(db, SQLITE_BUSY, "unable to close due to unfinalized "
846        "statements or unfinished backups");
847     sqlite3_mutex_leave(db->mutex);
848     return SQLITE_BUSY;
849   }
850 
851 #ifdef SQLITE_ENABLE_SQLLOG
852   if( sqlite3GlobalConfig.xSqllog ){
853     /* Closing the handle. Fourth parameter is passed the value 2. */
854     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
855   }
856 #endif
857 
858   /* Convert the connection into a zombie and then close it.
859   */
860   db->magic = SQLITE_MAGIC_ZOMBIE;
861   sqlite3LeaveMutexAndCloseZombie(db);
862   return SQLITE_OK;
863 }
864 
865 /*
866 ** Two variations on the public interface for closing a database
867 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
868 ** leaves the connection option if there are unfinalized prepared
869 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
870 ** version forces the connection to become a zombie if there are
871 ** unclosed resources, and arranges for deallocation when the last
872 ** prepare statement or sqlite3_backup closes.
873 */
874 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
875 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
876 
877 
878 /*
879 ** Close the mutex on database connection db.
880 **
881 ** Furthermore, if database connection db is a zombie (meaning that there
882 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
883 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
884 ** finished, then free all resources.
885 */
886 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
887   HashElem *i;                    /* Hash table iterator */
888   int j;
889 
890   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
891   ** or if the connection has not yet been closed by sqlite3_close_v2(),
892   ** then just leave the mutex and return.
893   */
894   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
895     sqlite3_mutex_leave(db->mutex);
896     return;
897   }
898 
899   /* If we reach this point, it means that the database connection has
900   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
901   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
902   ** go ahead and free all resources.
903   */
904 
905   /* If a transaction is open, roll it back. This also ensures that if
906   ** any database schemas have been modified by an uncommitted transaction
907   ** they are reset. And that the required b-tree mutex is held to make
908   ** the pager rollback and schema reset an atomic operation. */
909   sqlite3RollbackAll(db, SQLITE_OK);
910 
911   /* Free any outstanding Savepoint structures. */
912   sqlite3CloseSavepoints(db);
913 
914   /* Close all database connections */
915   for(j=0; j<db->nDb; j++){
916     struct Db *pDb = &db->aDb[j];
917     if( pDb->pBt ){
918       sqlite3BtreeClose(pDb->pBt);
919       pDb->pBt = 0;
920       if( j!=1 ){
921         pDb->pSchema = 0;
922       }
923     }
924   }
925   /* Clear the TEMP schema separately and last */
926   if( db->aDb[1].pSchema ){
927     sqlite3SchemaClear(db->aDb[1].pSchema);
928   }
929   sqlite3VtabUnlockList(db);
930 
931   /* Free up the array of auxiliary databases */
932   sqlite3CollapseDatabaseArray(db);
933   assert( db->nDb<=2 );
934   assert( db->aDb==db->aDbStatic );
935 
936   /* Tell the code in notify.c that the connection no longer holds any
937   ** locks and does not require any further unlock-notify callbacks.
938   */
939   sqlite3ConnectionClosed(db);
940 
941   for(j=0; j<ArraySize(db->aFunc.a); j++){
942     FuncDef *pNext, *pHash, *p;
943     for(p=db->aFunc.a[j]; p; p=pHash){
944       pHash = p->pHash;
945       while( p ){
946         functionDestroy(db, p);
947         pNext = p->pNext;
948         sqlite3DbFree(db, p);
949         p = pNext;
950       }
951     }
952   }
953   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
954     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
955     /* Invoke any destructors registered for collation sequence user data. */
956     for(j=0; j<3; j++){
957       if( pColl[j].xDel ){
958         pColl[j].xDel(pColl[j].pUser);
959       }
960     }
961     sqlite3DbFree(db, pColl);
962   }
963   sqlite3HashClear(&db->aCollSeq);
964 #ifndef SQLITE_OMIT_VIRTUALTABLE
965   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
966     Module *pMod = (Module *)sqliteHashData(i);
967     if( pMod->xDestroy ){
968       pMod->xDestroy(pMod->pAux);
969     }
970     sqlite3DbFree(db, pMod);
971   }
972   sqlite3HashClear(&db->aModule);
973 #endif
974 
975   sqlite3Error(db, SQLITE_OK, 0); /* Deallocates any cached error strings. */
976   if( db->pErr ){
977     sqlite3ValueFree(db->pErr);
978   }
979   sqlite3CloseExtensions(db);
980 
981   db->magic = SQLITE_MAGIC_ERROR;
982 
983   /* The temp-database schema is allocated differently from the other schema
984   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
985   ** So it needs to be freed here. Todo: Why not roll the temp schema into
986   ** the same sqliteMalloc() as the one that allocates the database
987   ** structure?
988   */
989   sqlite3DbFree(db, db->aDb[1].pSchema);
990   sqlite3_mutex_leave(db->mutex);
991   db->magic = SQLITE_MAGIC_CLOSED;
992   sqlite3_mutex_free(db->mutex);
993   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
994   if( db->lookaside.bMalloced ){
995     sqlite3_free(db->lookaside.pStart);
996   }
997   sqlite3_free(db);
998 }
999 
1000 /*
1001 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1002 ** any open cursors are invalidated ("tripped" - as in "tripping a circuit
1003 ** breaker") and made to return tripCode if there are any further
1004 ** attempts to use that cursor.
1005 */
1006 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1007   int i;
1008   int inTrans = 0;
1009   assert( sqlite3_mutex_held(db->mutex) );
1010   sqlite3BeginBenignMalloc();
1011 
1012   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1013   ** This is important in case the transaction being rolled back has
1014   ** modified the database schema. If the b-tree mutexes are not taken
1015   ** here, then another shared-cache connection might sneak in between
1016   ** the database rollback and schema reset, which can cause false
1017   ** corruption reports in some cases.  */
1018   sqlite3BtreeEnterAll(db);
1019 
1020   for(i=0; i<db->nDb; i++){
1021     Btree *p = db->aDb[i].pBt;
1022     if( p ){
1023       if( sqlite3BtreeIsInTrans(p) ){
1024         inTrans = 1;
1025       }
1026       sqlite3BtreeRollback(p, tripCode);
1027     }
1028   }
1029   sqlite3VtabRollback(db);
1030   sqlite3EndBenignMalloc();
1031 
1032   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1033     sqlite3ExpirePreparedStatements(db);
1034     sqlite3ResetAllSchemasOfConnection(db);
1035   }
1036   sqlite3BtreeLeaveAll(db);
1037 
1038   /* Any deferred constraint violations have now been resolved. */
1039   db->nDeferredCons = 0;
1040 
1041   /* If one has been configured, invoke the rollback-hook callback */
1042   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1043     db->xRollbackCallback(db->pRollbackArg);
1044   }
1045 }
1046 
1047 /*
1048 ** Return a static string containing the name corresponding to the error code
1049 ** specified in the argument.
1050 */
1051 #if defined(SQLITE_DEBUG) || defined(SQLITE_TEST) || \
1052     defined(SQLITE_DEBUG_OS_TRACE)
1053 const char *sqlite3ErrName(int rc){
1054   const char *zName = 0;
1055   int i, origRc = rc;
1056   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1057     switch( rc ){
1058       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1059       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1060       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1061       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1062       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1063       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1064       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1065       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1066       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1067       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1068       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1069       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1070       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1071       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1072       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1073       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1074       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1075       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1076       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1077       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1078       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1079       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1080       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1081       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1082       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1083       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1084       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1085       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1086       case SQLITE_IOERR_BLOCKED:      zName = "SQLITE_IOERR_BLOCKED";     break;
1087       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1088       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1089       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1090                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1091       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1092       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1093       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1094       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1095       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1096       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1097       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1098       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1099       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1100       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1101       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1102       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1103       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1104       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1105       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1106       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1107       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1108       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1109       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1110       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1111       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1112       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1113       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1114       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1115       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1116       case SQLITE_CONSTRAINT_FOREIGNKEY:
1117                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1118       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1119       case SQLITE_CONSTRAINT_PRIMARYKEY:
1120                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1121       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1122       case SQLITE_CONSTRAINT_COMMITHOOK:
1123                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1124       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1125       case SQLITE_CONSTRAINT_FUNCTION:
1126                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1127       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1128       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1129       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1130       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1131       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1132       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1133       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1134       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1135       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1136       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1137       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1138                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1139       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1140       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1141       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1142     }
1143   }
1144   if( zName==0 ){
1145     static char zBuf[50];
1146     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1147     zName = zBuf;
1148   }
1149   return zName;
1150 }
1151 #endif
1152 
1153 /*
1154 ** Return a static string that describes the kind of error specified in the
1155 ** argument.
1156 */
1157 const char *sqlite3ErrStr(int rc){
1158   static const char* const aMsg[] = {
1159     /* SQLITE_OK          */ "not an error",
1160     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1161     /* SQLITE_INTERNAL    */ 0,
1162     /* SQLITE_PERM        */ "access permission denied",
1163     /* SQLITE_ABORT       */ "callback requested query abort",
1164     /* SQLITE_BUSY        */ "database is locked",
1165     /* SQLITE_LOCKED      */ "database table is locked",
1166     /* SQLITE_NOMEM       */ "out of memory",
1167     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1168     /* SQLITE_INTERRUPT   */ "interrupted",
1169     /* SQLITE_IOERR       */ "disk I/O error",
1170     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1171     /* SQLITE_NOTFOUND    */ "unknown operation",
1172     /* SQLITE_FULL        */ "database or disk is full",
1173     /* SQLITE_CANTOPEN    */ "unable to open database file",
1174     /* SQLITE_PROTOCOL    */ "locking protocol",
1175     /* SQLITE_EMPTY       */ "table contains no data",
1176     /* SQLITE_SCHEMA      */ "database schema has changed",
1177     /* SQLITE_TOOBIG      */ "string or blob too big",
1178     /* SQLITE_CONSTRAINT  */ "constraint failed",
1179     /* SQLITE_MISMATCH    */ "datatype mismatch",
1180     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1181     /* SQLITE_NOLFS       */ "large file support is disabled",
1182     /* SQLITE_AUTH        */ "authorization denied",
1183     /* SQLITE_FORMAT      */ "auxiliary database format error",
1184     /* SQLITE_RANGE       */ "bind or column index out of range",
1185     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1186   };
1187   const char *zErr = "unknown error";
1188   switch( rc ){
1189     case SQLITE_ABORT_ROLLBACK: {
1190       zErr = "abort due to ROLLBACK";
1191       break;
1192     }
1193     default: {
1194       rc &= 0xff;
1195       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1196         zErr = aMsg[rc];
1197       }
1198       break;
1199     }
1200   }
1201   return zErr;
1202 }
1203 
1204 /*
1205 ** This routine implements a busy callback that sleeps and tries
1206 ** again until a timeout value is reached.  The timeout value is
1207 ** an integer number of milliseconds passed in as the first
1208 ** argument.
1209 */
1210 static int sqliteDefaultBusyCallback(
1211  void *ptr,               /* Database connection */
1212  int count                /* Number of times table has been busy */
1213 ){
1214 #if SQLITE_OS_WIN || (defined(HAVE_USLEEP) && HAVE_USLEEP)
1215   static const u8 delays[] =
1216      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1217   static const u8 totals[] =
1218      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1219 # define NDELAY ArraySize(delays)
1220   sqlite3 *db = (sqlite3 *)ptr;
1221   int timeout = db->busyTimeout;
1222   int delay, prior;
1223 
1224   assert( count>=0 );
1225   if( count < NDELAY ){
1226     delay = delays[count];
1227     prior = totals[count];
1228   }else{
1229     delay = delays[NDELAY-1];
1230     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1231   }
1232   if( prior + delay > timeout ){
1233     delay = timeout - prior;
1234     if( delay<=0 ) return 0;
1235   }
1236   sqlite3OsSleep(db->pVfs, delay*1000);
1237   return 1;
1238 #else
1239   sqlite3 *db = (sqlite3 *)ptr;
1240   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1241   if( (count+1)*1000 > timeout ){
1242     return 0;
1243   }
1244   sqlite3OsSleep(db->pVfs, 1000000);
1245   return 1;
1246 #endif
1247 }
1248 
1249 /*
1250 ** Invoke the given busy handler.
1251 **
1252 ** This routine is called when an operation failed with a lock.
1253 ** If this routine returns non-zero, the lock is retried.  If it
1254 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1255 */
1256 int sqlite3InvokeBusyHandler(BusyHandler *p){
1257   int rc;
1258   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1259   rc = p->xFunc(p->pArg, p->nBusy);
1260   if( rc==0 ){
1261     p->nBusy = -1;
1262   }else{
1263     p->nBusy++;
1264   }
1265   return rc;
1266 }
1267 
1268 /*
1269 ** This routine sets the busy callback for an Sqlite database to the
1270 ** given callback function with the given argument.
1271 */
1272 int sqlite3_busy_handler(
1273   sqlite3 *db,
1274   int (*xBusy)(void*,int),
1275   void *pArg
1276 ){
1277   sqlite3_mutex_enter(db->mutex);
1278   db->busyHandler.xFunc = xBusy;
1279   db->busyHandler.pArg = pArg;
1280   db->busyHandler.nBusy = 0;
1281   db->busyTimeout = 0;
1282   sqlite3_mutex_leave(db->mutex);
1283   return SQLITE_OK;
1284 }
1285 
1286 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1287 /*
1288 ** This routine sets the progress callback for an Sqlite database to the
1289 ** given callback function with the given argument. The progress callback will
1290 ** be invoked every nOps opcodes.
1291 */
1292 void sqlite3_progress_handler(
1293   sqlite3 *db,
1294   int nOps,
1295   int (*xProgress)(void*),
1296   void *pArg
1297 ){
1298   sqlite3_mutex_enter(db->mutex);
1299   if( nOps>0 ){
1300     db->xProgress = xProgress;
1301     db->nProgressOps = nOps;
1302     db->pProgressArg = pArg;
1303   }else{
1304     db->xProgress = 0;
1305     db->nProgressOps = 0;
1306     db->pProgressArg = 0;
1307   }
1308   sqlite3_mutex_leave(db->mutex);
1309 }
1310 #endif
1311 
1312 
1313 /*
1314 ** This routine installs a default busy handler that waits for the
1315 ** specified number of milliseconds before returning 0.
1316 */
1317 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1318   if( ms>0 ){
1319     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1320     db->busyTimeout = ms;
1321   }else{
1322     sqlite3_busy_handler(db, 0, 0);
1323   }
1324   return SQLITE_OK;
1325 }
1326 
1327 /*
1328 ** Cause any pending operation to stop at its earliest opportunity.
1329 */
1330 void sqlite3_interrupt(sqlite3 *db){
1331   db->u1.isInterrupted = 1;
1332 }
1333 
1334 
1335 /*
1336 ** This function is exactly the same as sqlite3_create_function(), except
1337 ** that it is designed to be called by internal code. The difference is
1338 ** that if a malloc() fails in sqlite3_create_function(), an error code
1339 ** is returned and the mallocFailed flag cleared.
1340 */
1341 int sqlite3CreateFunc(
1342   sqlite3 *db,
1343   const char *zFunctionName,
1344   int nArg,
1345   int enc,
1346   void *pUserData,
1347   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1348   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1349   void (*xFinal)(sqlite3_context*),
1350   FuncDestructor *pDestructor
1351 ){
1352   FuncDef *p;
1353   int nName;
1354 
1355   assert( sqlite3_mutex_held(db->mutex) );
1356   if( zFunctionName==0 ||
1357       (xFunc && (xFinal || xStep)) ||
1358       (!xFunc && (xFinal && !xStep)) ||
1359       (!xFunc && (!xFinal && xStep)) ||
1360       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1361       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1362     return SQLITE_MISUSE_BKPT;
1363   }
1364 
1365 #ifndef SQLITE_OMIT_UTF16
1366   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1367   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1368   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1369   **
1370   ** If SQLITE_ANY is specified, add three versions of the function
1371   ** to the hash table.
1372   */
1373   if( enc==SQLITE_UTF16 ){
1374     enc = SQLITE_UTF16NATIVE;
1375   }else if( enc==SQLITE_ANY ){
1376     int rc;
1377     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8,
1378          pUserData, xFunc, xStep, xFinal, pDestructor);
1379     if( rc==SQLITE_OK ){
1380       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE,
1381           pUserData, xFunc, xStep, xFinal, pDestructor);
1382     }
1383     if( rc!=SQLITE_OK ){
1384       return rc;
1385     }
1386     enc = SQLITE_UTF16BE;
1387   }
1388 #else
1389   enc = SQLITE_UTF8;
1390 #endif
1391 
1392   /* Check if an existing function is being overridden or deleted. If so,
1393   ** and there are active VMs, then return SQLITE_BUSY. If a function
1394   ** is being overridden/deleted but there are no active VMs, allow the
1395   ** operation to continue but invalidate all precompiled statements.
1396   */
1397   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 0);
1398   if( p && p->iPrefEnc==enc && p->nArg==nArg ){
1399     if( db->nVdbeActive ){
1400       sqlite3Error(db, SQLITE_BUSY,
1401         "unable to delete/modify user-function due to active statements");
1402       assert( !db->mallocFailed );
1403       return SQLITE_BUSY;
1404     }else{
1405       sqlite3ExpirePreparedStatements(db);
1406     }
1407   }
1408 
1409   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 1);
1410   assert(p || db->mallocFailed);
1411   if( !p ){
1412     return SQLITE_NOMEM;
1413   }
1414 
1415   /* If an older version of the function with a configured destructor is
1416   ** being replaced invoke the destructor function here. */
1417   functionDestroy(db, p);
1418 
1419   if( pDestructor ){
1420     pDestructor->nRef++;
1421   }
1422   p->pDestructor = pDestructor;
1423   p->flags = 0;
1424   p->xFunc = xFunc;
1425   p->xStep = xStep;
1426   p->xFinalize = xFinal;
1427   p->pUserData = pUserData;
1428   p->nArg = (u16)nArg;
1429   return SQLITE_OK;
1430 }
1431 
1432 /*
1433 ** Create new user functions.
1434 */
1435 int sqlite3_create_function(
1436   sqlite3 *db,
1437   const char *zFunc,
1438   int nArg,
1439   int enc,
1440   void *p,
1441   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1442   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1443   void (*xFinal)(sqlite3_context*)
1444 ){
1445   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xFunc, xStep,
1446                                     xFinal, 0);
1447 }
1448 
1449 int sqlite3_create_function_v2(
1450   sqlite3 *db,
1451   const char *zFunc,
1452   int nArg,
1453   int enc,
1454   void *p,
1455   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1456   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1457   void (*xFinal)(sqlite3_context*),
1458   void (*xDestroy)(void *)
1459 ){
1460   int rc = SQLITE_ERROR;
1461   FuncDestructor *pArg = 0;
1462   sqlite3_mutex_enter(db->mutex);
1463   if( xDestroy ){
1464     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1465     if( !pArg ){
1466       xDestroy(p);
1467       goto out;
1468     }
1469     pArg->xDestroy = xDestroy;
1470     pArg->pUserData = p;
1471   }
1472   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, pArg);
1473   if( pArg && pArg->nRef==0 ){
1474     assert( rc!=SQLITE_OK );
1475     xDestroy(p);
1476     sqlite3DbFree(db, pArg);
1477   }
1478 
1479  out:
1480   rc = sqlite3ApiExit(db, rc);
1481   sqlite3_mutex_leave(db->mutex);
1482   return rc;
1483 }
1484 
1485 #ifndef SQLITE_OMIT_UTF16
1486 int sqlite3_create_function16(
1487   sqlite3 *db,
1488   const void *zFunctionName,
1489   int nArg,
1490   int eTextRep,
1491   void *p,
1492   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
1493   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1494   void (*xFinal)(sqlite3_context*)
1495 ){
1496   int rc;
1497   char *zFunc8;
1498   sqlite3_mutex_enter(db->mutex);
1499   assert( !db->mallocFailed );
1500   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1501   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
1502   sqlite3DbFree(db, zFunc8);
1503   rc = sqlite3ApiExit(db, rc);
1504   sqlite3_mutex_leave(db->mutex);
1505   return rc;
1506 }
1507 #endif
1508 
1509 
1510 /*
1511 ** Declare that a function has been overloaded by a virtual table.
1512 **
1513 ** If the function already exists as a regular global function, then
1514 ** this routine is a no-op.  If the function does not exist, then create
1515 ** a new one that always throws a run-time error.
1516 **
1517 ** When virtual tables intend to provide an overloaded function, they
1518 ** should call this routine to make sure the global function exists.
1519 ** A global function must exist in order for name resolution to work
1520 ** properly.
1521 */
1522 int sqlite3_overload_function(
1523   sqlite3 *db,
1524   const char *zName,
1525   int nArg
1526 ){
1527   int nName = sqlite3Strlen30(zName);
1528   int rc = SQLITE_OK;
1529   sqlite3_mutex_enter(db->mutex);
1530   if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
1531     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1532                            0, sqlite3InvalidFunction, 0, 0, 0);
1533   }
1534   rc = sqlite3ApiExit(db, rc);
1535   sqlite3_mutex_leave(db->mutex);
1536   return rc;
1537 }
1538 
1539 #ifndef SQLITE_OMIT_TRACE
1540 /*
1541 ** Register a trace function.  The pArg from the previously registered trace
1542 ** is returned.
1543 **
1544 ** A NULL trace function means that no tracing is executes.  A non-NULL
1545 ** trace is a pointer to a function that is invoked at the start of each
1546 ** SQL statement.
1547 */
1548 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1549   void *pOld;
1550   sqlite3_mutex_enter(db->mutex);
1551   pOld = db->pTraceArg;
1552   db->xTrace = xTrace;
1553   db->pTraceArg = pArg;
1554   sqlite3_mutex_leave(db->mutex);
1555   return pOld;
1556 }
1557 /*
1558 ** Register a profile function.  The pArg from the previously registered
1559 ** profile function is returned.
1560 **
1561 ** A NULL profile function means that no profiling is executes.  A non-NULL
1562 ** profile is a pointer to a function that is invoked at the conclusion of
1563 ** each SQL statement that is run.
1564 */
1565 void *sqlite3_profile(
1566   sqlite3 *db,
1567   void (*xProfile)(void*,const char*,sqlite_uint64),
1568   void *pArg
1569 ){
1570   void *pOld;
1571   sqlite3_mutex_enter(db->mutex);
1572   pOld = db->pProfileArg;
1573   db->xProfile = xProfile;
1574   db->pProfileArg = pArg;
1575   sqlite3_mutex_leave(db->mutex);
1576   return pOld;
1577 }
1578 #endif /* SQLITE_OMIT_TRACE */
1579 
1580 /*
1581 ** Register a function to be invoked when a transaction commits.
1582 ** If the invoked function returns non-zero, then the commit becomes a
1583 ** rollback.
1584 */
1585 void *sqlite3_commit_hook(
1586   sqlite3 *db,              /* Attach the hook to this database */
1587   int (*xCallback)(void*),  /* Function to invoke on each commit */
1588   void *pArg                /* Argument to the function */
1589 ){
1590   void *pOld;
1591   sqlite3_mutex_enter(db->mutex);
1592   pOld = db->pCommitArg;
1593   db->xCommitCallback = xCallback;
1594   db->pCommitArg = pArg;
1595   sqlite3_mutex_leave(db->mutex);
1596   return pOld;
1597 }
1598 
1599 /*
1600 ** Register a callback to be invoked each time a row is updated,
1601 ** inserted or deleted using this database connection.
1602 */
1603 void *sqlite3_update_hook(
1604   sqlite3 *db,              /* Attach the hook to this database */
1605   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1606   void *pArg                /* Argument to the function */
1607 ){
1608   void *pRet;
1609   sqlite3_mutex_enter(db->mutex);
1610   pRet = db->pUpdateArg;
1611   db->xUpdateCallback = xCallback;
1612   db->pUpdateArg = pArg;
1613   sqlite3_mutex_leave(db->mutex);
1614   return pRet;
1615 }
1616 
1617 /*
1618 ** Register a callback to be invoked each time a transaction is rolled
1619 ** back by this database connection.
1620 */
1621 void *sqlite3_rollback_hook(
1622   sqlite3 *db,              /* Attach the hook to this database */
1623   void (*xCallback)(void*), /* Callback function */
1624   void *pArg                /* Argument to the function */
1625 ){
1626   void *pRet;
1627   sqlite3_mutex_enter(db->mutex);
1628   pRet = db->pRollbackArg;
1629   db->xRollbackCallback = xCallback;
1630   db->pRollbackArg = pArg;
1631   sqlite3_mutex_leave(db->mutex);
1632   return pRet;
1633 }
1634 
1635 #ifndef SQLITE_OMIT_WAL
1636 /*
1637 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1638 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1639 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1640 ** wal_autocheckpoint()).
1641 */
1642 int sqlite3WalDefaultHook(
1643   void *pClientData,     /* Argument */
1644   sqlite3 *db,           /* Connection */
1645   const char *zDb,       /* Database */
1646   int nFrame             /* Size of WAL */
1647 ){
1648   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1649     sqlite3BeginBenignMalloc();
1650     sqlite3_wal_checkpoint(db, zDb);
1651     sqlite3EndBenignMalloc();
1652   }
1653   return SQLITE_OK;
1654 }
1655 #endif /* SQLITE_OMIT_WAL */
1656 
1657 /*
1658 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1659 ** a database after committing a transaction if there are nFrame or
1660 ** more frames in the log file. Passing zero or a negative value as the
1661 ** nFrame parameter disables automatic checkpoints entirely.
1662 **
1663 ** The callback registered by this function replaces any existing callback
1664 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1665 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1666 ** configured by this function.
1667 */
1668 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1669 #ifdef SQLITE_OMIT_WAL
1670   UNUSED_PARAMETER(db);
1671   UNUSED_PARAMETER(nFrame);
1672 #else
1673   if( nFrame>0 ){
1674     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1675   }else{
1676     sqlite3_wal_hook(db, 0, 0);
1677   }
1678 #endif
1679   return SQLITE_OK;
1680 }
1681 
1682 /*
1683 ** Register a callback to be invoked each time a transaction is written
1684 ** into the write-ahead-log by this database connection.
1685 */
1686 void *sqlite3_wal_hook(
1687   sqlite3 *db,                    /* Attach the hook to this db handle */
1688   int(*xCallback)(void *, sqlite3*, const char*, int),
1689   void *pArg                      /* First argument passed to xCallback() */
1690 ){
1691 #ifndef SQLITE_OMIT_WAL
1692   void *pRet;
1693   sqlite3_mutex_enter(db->mutex);
1694   pRet = db->pWalArg;
1695   db->xWalCallback = xCallback;
1696   db->pWalArg = pArg;
1697   sqlite3_mutex_leave(db->mutex);
1698   return pRet;
1699 #else
1700   return 0;
1701 #endif
1702 }
1703 
1704 /*
1705 ** Checkpoint database zDb.
1706 */
1707 int sqlite3_wal_checkpoint_v2(
1708   sqlite3 *db,                    /* Database handle */
1709   const char *zDb,                /* Name of attached database (or NULL) */
1710   int eMode,                      /* SQLITE_CHECKPOINT_* value */
1711   int *pnLog,                     /* OUT: Size of WAL log in frames */
1712   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
1713 ){
1714 #ifdef SQLITE_OMIT_WAL
1715   return SQLITE_OK;
1716 #else
1717   int rc;                         /* Return code */
1718   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
1719 
1720   /* Initialize the output variables to -1 in case an error occurs. */
1721   if( pnLog ) *pnLog = -1;
1722   if( pnCkpt ) *pnCkpt = -1;
1723 
1724   assert( SQLITE_CHECKPOINT_FULL>SQLITE_CHECKPOINT_PASSIVE );
1725   assert( SQLITE_CHECKPOINT_FULL<SQLITE_CHECKPOINT_RESTART );
1726   assert( SQLITE_CHECKPOINT_PASSIVE+2==SQLITE_CHECKPOINT_RESTART );
1727   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_RESTART ){
1728     return SQLITE_MISUSE;
1729   }
1730 
1731   sqlite3_mutex_enter(db->mutex);
1732   if( zDb && zDb[0] ){
1733     iDb = sqlite3FindDbName(db, zDb);
1734   }
1735   if( iDb<0 ){
1736     rc = SQLITE_ERROR;
1737     sqlite3Error(db, SQLITE_ERROR, "unknown database: %s", zDb);
1738   }else{
1739     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
1740     sqlite3Error(db, rc, 0);
1741   }
1742   rc = sqlite3ApiExit(db, rc);
1743   sqlite3_mutex_leave(db->mutex);
1744   return rc;
1745 #endif
1746 }
1747 
1748 
1749 /*
1750 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
1751 ** to contains a zero-length string, all attached databases are
1752 ** checkpointed.
1753 */
1754 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
1755   return sqlite3_wal_checkpoint_v2(db, zDb, SQLITE_CHECKPOINT_PASSIVE, 0, 0);
1756 }
1757 
1758 #ifndef SQLITE_OMIT_WAL
1759 /*
1760 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
1761 ** not currently open in WAL mode.
1762 **
1763 ** If a transaction is open on the database being checkpointed, this
1764 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
1765 ** an error occurs while running the checkpoint, an SQLite error code is
1766 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
1767 **
1768 ** The mutex on database handle db should be held by the caller. The mutex
1769 ** associated with the specific b-tree being checkpointed is taken by
1770 ** this function while the checkpoint is running.
1771 **
1772 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
1773 ** checkpointed. If an error is encountered it is returned immediately -
1774 ** no attempt is made to checkpoint any remaining databases.
1775 **
1776 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
1777 */
1778 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
1779   int rc = SQLITE_OK;             /* Return code */
1780   int i;                          /* Used to iterate through attached dbs */
1781   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
1782 
1783   assert( sqlite3_mutex_held(db->mutex) );
1784   assert( !pnLog || *pnLog==-1 );
1785   assert( !pnCkpt || *pnCkpt==-1 );
1786 
1787   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
1788     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
1789       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
1790       pnLog = 0;
1791       pnCkpt = 0;
1792       if( rc==SQLITE_BUSY ){
1793         bBusy = 1;
1794         rc = SQLITE_OK;
1795       }
1796     }
1797   }
1798 
1799   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
1800 }
1801 #endif /* SQLITE_OMIT_WAL */
1802 
1803 /*
1804 ** This function returns true if main-memory should be used instead of
1805 ** a temporary file for transient pager files and statement journals.
1806 ** The value returned depends on the value of db->temp_store (runtime
1807 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
1808 ** following table describes the relationship between these two values
1809 ** and this functions return value.
1810 **
1811 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
1812 **   -----------------     --------------     ------------------------------
1813 **   0                     any                file      (return 0)
1814 **   1                     1                  file      (return 0)
1815 **   1                     2                  memory    (return 1)
1816 **   1                     0                  file      (return 0)
1817 **   2                     1                  file      (return 0)
1818 **   2                     2                  memory    (return 1)
1819 **   2                     0                  memory    (return 1)
1820 **   3                     any                memory    (return 1)
1821 */
1822 int sqlite3TempInMemory(const sqlite3 *db){
1823 #if SQLITE_TEMP_STORE==1
1824   return ( db->temp_store==2 );
1825 #endif
1826 #if SQLITE_TEMP_STORE==2
1827   return ( db->temp_store!=1 );
1828 #endif
1829 #if SQLITE_TEMP_STORE==3
1830   return 1;
1831 #endif
1832 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
1833   return 0;
1834 #endif
1835 }
1836 
1837 /*
1838 ** Return UTF-8 encoded English language explanation of the most recent
1839 ** error.
1840 */
1841 const char *sqlite3_errmsg(sqlite3 *db){
1842   const char *z;
1843   if( !db ){
1844     return sqlite3ErrStr(SQLITE_NOMEM);
1845   }
1846   if( !sqlite3SafetyCheckSickOrOk(db) ){
1847     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
1848   }
1849   sqlite3_mutex_enter(db->mutex);
1850   if( db->mallocFailed ){
1851     z = sqlite3ErrStr(SQLITE_NOMEM);
1852   }else{
1853     z = (char*)sqlite3_value_text(db->pErr);
1854     assert( !db->mallocFailed );
1855     if( z==0 ){
1856       z = sqlite3ErrStr(db->errCode);
1857     }
1858   }
1859   sqlite3_mutex_leave(db->mutex);
1860   return z;
1861 }
1862 
1863 #ifndef SQLITE_OMIT_UTF16
1864 /*
1865 ** Return UTF-16 encoded English language explanation of the most recent
1866 ** error.
1867 */
1868 const void *sqlite3_errmsg16(sqlite3 *db){
1869   static const u16 outOfMem[] = {
1870     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
1871   };
1872   static const u16 misuse[] = {
1873     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
1874     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
1875     'c', 'a', 'l', 'l', 'e', 'd', ' ',
1876     'o', 'u', 't', ' ',
1877     'o', 'f', ' ',
1878     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
1879   };
1880 
1881   const void *z;
1882   if( !db ){
1883     return (void *)outOfMem;
1884   }
1885   if( !sqlite3SafetyCheckSickOrOk(db) ){
1886     return (void *)misuse;
1887   }
1888   sqlite3_mutex_enter(db->mutex);
1889   if( db->mallocFailed ){
1890     z = (void *)outOfMem;
1891   }else{
1892     z = sqlite3_value_text16(db->pErr);
1893     if( z==0 ){
1894       sqlite3ValueSetStr(db->pErr, -1, sqlite3ErrStr(db->errCode),
1895            SQLITE_UTF8, SQLITE_STATIC);
1896       z = sqlite3_value_text16(db->pErr);
1897     }
1898     /* A malloc() may have failed within the call to sqlite3_value_text16()
1899     ** above. If this is the case, then the db->mallocFailed flag needs to
1900     ** be cleared before returning. Do this directly, instead of via
1901     ** sqlite3ApiExit(), to avoid setting the database handle error message.
1902     */
1903     db->mallocFailed = 0;
1904   }
1905   sqlite3_mutex_leave(db->mutex);
1906   return z;
1907 }
1908 #endif /* SQLITE_OMIT_UTF16 */
1909 
1910 /*
1911 ** Return the most recent error code generated by an SQLite routine. If NULL is
1912 ** passed to this function, we assume a malloc() failed during sqlite3_open().
1913 */
1914 int sqlite3_errcode(sqlite3 *db){
1915   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
1916     return SQLITE_MISUSE_BKPT;
1917   }
1918   if( !db || db->mallocFailed ){
1919     return SQLITE_NOMEM;
1920   }
1921   return db->errCode & db->errMask;
1922 }
1923 int sqlite3_extended_errcode(sqlite3 *db){
1924   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
1925     return SQLITE_MISUSE_BKPT;
1926   }
1927   if( !db || db->mallocFailed ){
1928     return SQLITE_NOMEM;
1929   }
1930   return db->errCode;
1931 }
1932 
1933 /*
1934 ** Return a string that describes the kind of error specified in the
1935 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
1936 ** function.
1937 */
1938 const char *sqlite3_errstr(int rc){
1939   return sqlite3ErrStr(rc);
1940 }
1941 
1942 /*
1943 ** Create a new collating function for database "db".  The name is zName
1944 ** and the encoding is enc.
1945 */
1946 static int createCollation(
1947   sqlite3* db,
1948   const char *zName,
1949   u8 enc,
1950   void* pCtx,
1951   int(*xCompare)(void*,int,const void*,int,const void*),
1952   void(*xDel)(void*)
1953 ){
1954   CollSeq *pColl;
1955   int enc2;
1956   int nName = sqlite3Strlen30(zName);
1957 
1958   assert( sqlite3_mutex_held(db->mutex) );
1959 
1960   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1961   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1962   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1963   */
1964   enc2 = enc;
1965   testcase( enc2==SQLITE_UTF16 );
1966   testcase( enc2==SQLITE_UTF16_ALIGNED );
1967   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
1968     enc2 = SQLITE_UTF16NATIVE;
1969   }
1970   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
1971     return SQLITE_MISUSE_BKPT;
1972   }
1973 
1974   /* Check if this call is removing or replacing an existing collation
1975   ** sequence. If so, and there are active VMs, return busy. If there
1976   ** are no active VMs, invalidate any pre-compiled statements.
1977   */
1978   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
1979   if( pColl && pColl->xCmp ){
1980     if( db->nVdbeActive ){
1981       sqlite3Error(db, SQLITE_BUSY,
1982         "unable to delete/modify collation sequence due to active statements");
1983       return SQLITE_BUSY;
1984     }
1985     sqlite3ExpirePreparedStatements(db);
1986 
1987     /* If collation sequence pColl was created directly by a call to
1988     ** sqlite3_create_collation, and not generated by synthCollSeq(),
1989     ** then any copies made by synthCollSeq() need to be invalidated.
1990     ** Also, collation destructor - CollSeq.xDel() - function may need
1991     ** to be called.
1992     */
1993     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
1994       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName, nName);
1995       int j;
1996       for(j=0; j<3; j++){
1997         CollSeq *p = &aColl[j];
1998         if( p->enc==pColl->enc ){
1999           if( p->xDel ){
2000             p->xDel(p->pUser);
2001           }
2002           p->xCmp = 0;
2003         }
2004       }
2005     }
2006   }
2007 
2008   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2009   if( pColl==0 ) return SQLITE_NOMEM;
2010   pColl->xCmp = xCompare;
2011   pColl->pUser = pCtx;
2012   pColl->xDel = xDel;
2013   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2014   sqlite3Error(db, SQLITE_OK, 0);
2015   return SQLITE_OK;
2016 }
2017 
2018 
2019 /*
2020 ** This array defines hard upper bounds on limit values.  The
2021 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2022 ** #defines in sqlite3.h.
2023 */
2024 static const int aHardLimit[] = {
2025   SQLITE_MAX_LENGTH,
2026   SQLITE_MAX_SQL_LENGTH,
2027   SQLITE_MAX_COLUMN,
2028   SQLITE_MAX_EXPR_DEPTH,
2029   SQLITE_MAX_COMPOUND_SELECT,
2030   SQLITE_MAX_VDBE_OP,
2031   SQLITE_MAX_FUNCTION_ARG,
2032   SQLITE_MAX_ATTACHED,
2033   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2034   SQLITE_MAX_VARIABLE_NUMBER,
2035   SQLITE_MAX_TRIGGER_DEPTH,
2036 };
2037 
2038 /*
2039 ** Make sure the hard limits are set to reasonable values
2040 */
2041 #if SQLITE_MAX_LENGTH<100
2042 # error SQLITE_MAX_LENGTH must be at least 100
2043 #endif
2044 #if SQLITE_MAX_SQL_LENGTH<100
2045 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2046 #endif
2047 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2048 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2049 #endif
2050 #if SQLITE_MAX_COMPOUND_SELECT<2
2051 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2052 #endif
2053 #if SQLITE_MAX_VDBE_OP<40
2054 # error SQLITE_MAX_VDBE_OP must be at least 40
2055 #endif
2056 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
2057 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
2058 #endif
2059 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>62
2060 # error SQLITE_MAX_ATTACHED must be between 0 and 62
2061 #endif
2062 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2063 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2064 #endif
2065 #if SQLITE_MAX_COLUMN>32767
2066 # error SQLITE_MAX_COLUMN must not exceed 32767
2067 #endif
2068 #if SQLITE_MAX_TRIGGER_DEPTH<1
2069 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2070 #endif
2071 
2072 
2073 /*
2074 ** Change the value of a limit.  Report the old value.
2075 ** If an invalid limit index is supplied, report -1.
2076 ** Make no changes but still report the old value if the
2077 ** new limit is negative.
2078 **
2079 ** A new lower limit does not shrink existing constructs.
2080 ** It merely prevents new constructs that exceed the limit
2081 ** from forming.
2082 */
2083 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2084   int oldLimit;
2085 
2086 
2087   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2088   ** there is a hard upper bound set at compile-time by a C preprocessor
2089   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2090   ** "_MAX_".)
2091   */
2092   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2093   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2094   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2095   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2096   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2097   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2098   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2099   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2100   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2101                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2102   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2103   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2104   assert( SQLITE_LIMIT_TRIGGER_DEPTH==(SQLITE_N_LIMIT-1) );
2105 
2106 
2107   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2108     return -1;
2109   }
2110   oldLimit = db->aLimit[limitId];
2111   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2112     if( newLimit>aHardLimit[limitId] ){
2113       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2114     }
2115     db->aLimit[limitId] = newLimit;
2116   }
2117   return oldLimit;                     /* IMP: R-53341-35419 */
2118 }
2119 
2120 /*
2121 ** This function is used to parse both URIs and non-URI filenames passed by the
2122 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2123 ** URIs specified as part of ATTACH statements.
2124 **
2125 ** The first argument to this function is the name of the VFS to use (or
2126 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2127 ** query parameter. The second argument contains the URI (or non-URI filename)
2128 ** itself. When this function is called the *pFlags variable should contain
2129 ** the default flags to open the database handle with. The value stored in
2130 ** *pFlags may be updated before returning if the URI filename contains
2131 ** "cache=xxx" or "mode=xxx" query parameters.
2132 **
2133 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2134 ** the VFS that should be used to open the database file. *pzFile is set to
2135 ** point to a buffer containing the name of the file to open. It is the
2136 ** responsibility of the caller to eventually call sqlite3_free() to release
2137 ** this buffer.
2138 **
2139 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2140 ** may be set to point to a buffer containing an English language error
2141 ** message. It is the responsibility of the caller to eventually release
2142 ** this buffer by calling sqlite3_free().
2143 */
2144 int sqlite3ParseUri(
2145   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2146   const char *zUri,               /* Nul-terminated URI to parse */
2147   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2148   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2149   char **pzFile,                  /* OUT: Filename component of URI */
2150   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2151 ){
2152   int rc = SQLITE_OK;
2153   unsigned int flags = *pFlags;
2154   const char *zVfs = zDefaultVfs;
2155   char *zFile;
2156   char c;
2157   int nUri = sqlite3Strlen30(zUri);
2158 
2159   assert( *pzErrMsg==0 );
2160 
2161   if( ((flags & SQLITE_OPEN_URI) || sqlite3GlobalConfig.bOpenUri)
2162    && nUri>=5 && memcmp(zUri, "file:", 5)==0
2163   ){
2164     char *zOpt;
2165     int eState;                   /* Parser state when parsing URI */
2166     int iIn;                      /* Input character index */
2167     int iOut = 0;                 /* Output character index */
2168     int nByte = nUri+2;           /* Bytes of space to allocate */
2169 
2170     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2171     ** method that there may be extra parameters following the file-name.  */
2172     flags |= SQLITE_OPEN_URI;
2173 
2174     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2175     zFile = sqlite3_malloc(nByte);
2176     if( !zFile ) return SQLITE_NOMEM;
2177 
2178     /* Discard the scheme and authority segments of the URI. */
2179     if( zUri[5]=='/' && zUri[6]=='/' ){
2180       iIn = 7;
2181       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2182 
2183       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2184         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2185             iIn-7, &zUri[7]);
2186         rc = SQLITE_ERROR;
2187         goto parse_uri_out;
2188       }
2189     }else{
2190       iIn = 5;
2191     }
2192 
2193     /* Copy the filename and any query parameters into the zFile buffer.
2194     ** Decode %HH escape codes along the way.
2195     **
2196     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2197     ** on the parsing context. As follows:
2198     **
2199     **   0: Parsing file-name.
2200     **   1: Parsing name section of a name=value query parameter.
2201     **   2: Parsing value section of a name=value query parameter.
2202     */
2203     eState = 0;
2204     while( (c = zUri[iIn])!=0 && c!='#' ){
2205       iIn++;
2206       if( c=='%'
2207        && sqlite3Isxdigit(zUri[iIn])
2208        && sqlite3Isxdigit(zUri[iIn+1])
2209       ){
2210         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2211         octet += sqlite3HexToInt(zUri[iIn++]);
2212 
2213         assert( octet>=0 && octet<256 );
2214         if( octet==0 ){
2215           /* This branch is taken when "%00" appears within the URI. In this
2216           ** case we ignore all text in the remainder of the path, name or
2217           ** value currently being parsed. So ignore the current character
2218           ** and skip to the next "?", "=" or "&", as appropriate. */
2219           while( (c = zUri[iIn])!=0 && c!='#'
2220               && (eState!=0 || c!='?')
2221               && (eState!=1 || (c!='=' && c!='&'))
2222               && (eState!=2 || c!='&')
2223           ){
2224             iIn++;
2225           }
2226           continue;
2227         }
2228         c = octet;
2229       }else if( eState==1 && (c=='&' || c=='=') ){
2230         if( zFile[iOut-1]==0 ){
2231           /* An empty option name. Ignore this option altogether. */
2232           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2233           continue;
2234         }
2235         if( c=='&' ){
2236           zFile[iOut++] = '\0';
2237         }else{
2238           eState = 2;
2239         }
2240         c = 0;
2241       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2242         c = 0;
2243         eState = 1;
2244       }
2245       zFile[iOut++] = c;
2246     }
2247     if( eState==1 ) zFile[iOut++] = '\0';
2248     zFile[iOut++] = '\0';
2249     zFile[iOut++] = '\0';
2250 
2251     /* Check if there were any options specified that should be interpreted
2252     ** here. Options that are interpreted here include "vfs" and those that
2253     ** correspond to flags that may be passed to the sqlite3_open_v2()
2254     ** method. */
2255     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2256     while( zOpt[0] ){
2257       int nOpt = sqlite3Strlen30(zOpt);
2258       char *zVal = &zOpt[nOpt+1];
2259       int nVal = sqlite3Strlen30(zVal);
2260 
2261       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2262         zVfs = zVal;
2263       }else{
2264         struct OpenMode {
2265           const char *z;
2266           int mode;
2267         } *aMode = 0;
2268         char *zModeType = 0;
2269         int mask = 0;
2270         int limit = 0;
2271 
2272         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2273           static struct OpenMode aCacheMode[] = {
2274             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2275             { "private", SQLITE_OPEN_PRIVATECACHE },
2276             { 0, 0 }
2277           };
2278 
2279           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2280           aMode = aCacheMode;
2281           limit = mask;
2282           zModeType = "cache";
2283         }
2284         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2285           static struct OpenMode aOpenMode[] = {
2286             { "ro",  SQLITE_OPEN_READONLY },
2287             { "rw",  SQLITE_OPEN_READWRITE },
2288             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2289             { "memory", SQLITE_OPEN_MEMORY },
2290             { 0, 0 }
2291           };
2292 
2293           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2294                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2295           aMode = aOpenMode;
2296           limit = mask & flags;
2297           zModeType = "access";
2298         }
2299 
2300         if( aMode ){
2301           int i;
2302           int mode = 0;
2303           for(i=0; aMode[i].z; i++){
2304             const char *z = aMode[i].z;
2305             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2306               mode = aMode[i].mode;
2307               break;
2308             }
2309           }
2310           if( mode==0 ){
2311             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2312             rc = SQLITE_ERROR;
2313             goto parse_uri_out;
2314           }
2315           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2316             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2317                                         zModeType, zVal);
2318             rc = SQLITE_PERM;
2319             goto parse_uri_out;
2320           }
2321           flags = (flags & ~mask) | mode;
2322         }
2323       }
2324 
2325       zOpt = &zVal[nVal+1];
2326     }
2327 
2328   }else{
2329     zFile = sqlite3_malloc(nUri+2);
2330     if( !zFile ) return SQLITE_NOMEM;
2331     memcpy(zFile, zUri, nUri);
2332     zFile[nUri] = '\0';
2333     zFile[nUri+1] = '\0';
2334     flags &= ~SQLITE_OPEN_URI;
2335   }
2336 
2337   *ppVfs = sqlite3_vfs_find(zVfs);
2338   if( *ppVfs==0 ){
2339     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2340     rc = SQLITE_ERROR;
2341   }
2342  parse_uri_out:
2343   if( rc!=SQLITE_OK ){
2344     sqlite3_free(zFile);
2345     zFile = 0;
2346   }
2347   *pFlags = flags;
2348   *pzFile = zFile;
2349   return rc;
2350 }
2351 
2352 
2353 /*
2354 ** This routine does the work of opening a database on behalf of
2355 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2356 ** is UTF-8 encoded.
2357 */
2358 static int openDatabase(
2359   const char *zFilename, /* Database filename UTF-8 encoded */
2360   sqlite3 **ppDb,        /* OUT: Returned database handle */
2361   unsigned int flags,    /* Operational flags */
2362   const char *zVfs       /* Name of the VFS to use */
2363 ){
2364   sqlite3 *db;                    /* Store allocated handle here */
2365   int rc;                         /* Return code */
2366   int isThreadsafe;               /* True for threadsafe connections */
2367   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2368   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2369 
2370   *ppDb = 0;
2371 #ifndef SQLITE_OMIT_AUTOINIT
2372   rc = sqlite3_initialize();
2373   if( rc ) return rc;
2374 #endif
2375 
2376   /* Only allow sensible combinations of bits in the flags argument.
2377   ** Throw an error if any non-sense combination is used.  If we
2378   ** do not block illegal combinations here, it could trigger
2379   ** assert() statements in deeper layers.  Sensible combinations
2380   ** are:
2381   **
2382   **  1:  SQLITE_OPEN_READONLY
2383   **  2:  SQLITE_OPEN_READWRITE
2384   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2385   */
2386   assert( SQLITE_OPEN_READONLY  == 0x01 );
2387   assert( SQLITE_OPEN_READWRITE == 0x02 );
2388   assert( SQLITE_OPEN_CREATE    == 0x04 );
2389   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2390   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2391   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2392   if( ((1<<(flags&7)) & 0x46)==0 ) return SQLITE_MISUSE_BKPT;
2393 
2394   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2395     isThreadsafe = 0;
2396   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2397     isThreadsafe = 0;
2398   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2399     isThreadsafe = 1;
2400   }else{
2401     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2402   }
2403   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2404     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2405   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2406     flags |= SQLITE_OPEN_SHAREDCACHE;
2407   }
2408 
2409   /* Remove harmful bits from the flags parameter
2410   **
2411   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2412   ** dealt with in the previous code block.  Besides these, the only
2413   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2414   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2415   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2416   ** off all other flags.
2417   */
2418   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2419                SQLITE_OPEN_EXCLUSIVE |
2420                SQLITE_OPEN_MAIN_DB |
2421                SQLITE_OPEN_TEMP_DB |
2422                SQLITE_OPEN_TRANSIENT_DB |
2423                SQLITE_OPEN_MAIN_JOURNAL |
2424                SQLITE_OPEN_TEMP_JOURNAL |
2425                SQLITE_OPEN_SUBJOURNAL |
2426                SQLITE_OPEN_MASTER_JOURNAL |
2427                SQLITE_OPEN_NOMUTEX |
2428                SQLITE_OPEN_FULLMUTEX |
2429                SQLITE_OPEN_WAL
2430              );
2431 
2432   /* Allocate the sqlite data structure */
2433   db = sqlite3MallocZero( sizeof(sqlite3) );
2434   if( db==0 ) goto opendb_out;
2435   if( isThreadsafe ){
2436     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2437     if( db->mutex==0 ){
2438       sqlite3_free(db);
2439       db = 0;
2440       goto opendb_out;
2441     }
2442   }
2443   sqlite3_mutex_enter(db->mutex);
2444   db->errMask = 0xff;
2445   db->nDb = 2;
2446   db->magic = SQLITE_MAGIC_BUSY;
2447   db->aDb = db->aDbStatic;
2448 
2449   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2450   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2451   db->autoCommit = 1;
2452   db->nextAutovac = -1;
2453   db->szMmap = sqlite3GlobalConfig.szMmap;
2454   db->nextPagesize = 0;
2455   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger
2456 #if !defined(SQLITE_DEAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2457                  | SQLITE_AutoIndex
2458 #endif
2459 #if SQLITE_DEFAULT_FILE_FORMAT<4
2460                  | SQLITE_LegacyFileFmt
2461 #endif
2462 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2463                  | SQLITE_LoadExtension
2464 #endif
2465 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2466                  | SQLITE_RecTriggers
2467 #endif
2468 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2469                  | SQLITE_ForeignKeys
2470 #endif
2471       ;
2472   sqlite3HashInit(&db->aCollSeq);
2473 #ifndef SQLITE_OMIT_VIRTUALTABLE
2474   sqlite3HashInit(&db->aModule);
2475 #endif
2476 
2477   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2478   ** and UTF-16, so add a version for each to avoid any unnecessary
2479   ** conversions. The only error that can occur here is a malloc() failure.
2480   */
2481   createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
2482   createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
2483   createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
2484   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2485   if( db->mallocFailed ){
2486     goto opendb_out;
2487   }
2488   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
2489   assert( db->pDfltColl!=0 );
2490 
2491   /* Also add a UTF-8 case-insensitive collation sequence. */
2492   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2493 
2494   /* Parse the filename/URI argument. */
2495   db->openFlags = flags;
2496   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2497   if( rc!=SQLITE_OK ){
2498     if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
2499     sqlite3Error(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2500     sqlite3_free(zErrMsg);
2501     goto opendb_out;
2502   }
2503 
2504   /* Open the backend database driver */
2505   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2506                         flags | SQLITE_OPEN_MAIN_DB);
2507   if( rc!=SQLITE_OK ){
2508     if( rc==SQLITE_IOERR_NOMEM ){
2509       rc = SQLITE_NOMEM;
2510     }
2511     sqlite3Error(db, rc, 0);
2512     goto opendb_out;
2513   }
2514   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2515   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2516 
2517 
2518   /* The default safety_level for the main database is 'full'; for the temp
2519   ** database it is 'NONE'. This matches the pager layer defaults.
2520   */
2521   db->aDb[0].zName = "main";
2522   db->aDb[0].safety_level = 3;
2523   db->aDb[1].zName = "temp";
2524   db->aDb[1].safety_level = 1;
2525 
2526   db->magic = SQLITE_MAGIC_OPEN;
2527   if( db->mallocFailed ){
2528     goto opendb_out;
2529   }
2530 
2531   /* Register all built-in functions, but do not attempt to read the
2532   ** database schema yet. This is delayed until the first time the database
2533   ** is accessed.
2534   */
2535   sqlite3Error(db, SQLITE_OK, 0);
2536   sqlite3RegisterBuiltinFunctions(db);
2537 
2538   /* Load automatic extensions - extensions that have been registered
2539   ** using the sqlite3_automatic_extension() API.
2540   */
2541   rc = sqlite3_errcode(db);
2542   if( rc==SQLITE_OK ){
2543     sqlite3AutoLoadExtensions(db);
2544     rc = sqlite3_errcode(db);
2545     if( rc!=SQLITE_OK ){
2546       goto opendb_out;
2547     }
2548   }
2549 
2550 #ifdef SQLITE_ENABLE_FTS1
2551   if( !db->mallocFailed ){
2552     extern int sqlite3Fts1Init(sqlite3*);
2553     rc = sqlite3Fts1Init(db);
2554   }
2555 #endif
2556 
2557 #ifdef SQLITE_ENABLE_FTS2
2558   if( !db->mallocFailed && rc==SQLITE_OK ){
2559     extern int sqlite3Fts2Init(sqlite3*);
2560     rc = sqlite3Fts2Init(db);
2561   }
2562 #endif
2563 
2564 #ifdef SQLITE_ENABLE_FTS3
2565   if( !db->mallocFailed && rc==SQLITE_OK ){
2566     rc = sqlite3Fts3Init(db);
2567   }
2568 #endif
2569 
2570 #ifdef SQLITE_ENABLE_ICU
2571   if( !db->mallocFailed && rc==SQLITE_OK ){
2572     rc = sqlite3IcuInit(db);
2573   }
2574 #endif
2575 
2576 #ifdef SQLITE_ENABLE_RTREE
2577   if( !db->mallocFailed && rc==SQLITE_OK){
2578     rc = sqlite3RtreeInit(db);
2579   }
2580 #endif
2581 
2582   sqlite3Error(db, rc, 0);
2583 
2584   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2585   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2586   ** mode.  Doing nothing at all also makes NORMAL the default.
2587   */
2588 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2589   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2590   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2591                           SQLITE_DEFAULT_LOCKING_MODE);
2592 #endif
2593 
2594   /* Enable the lookaside-malloc subsystem */
2595   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2596                         sqlite3GlobalConfig.nLookaside);
2597 
2598   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2599 
2600 opendb_out:
2601   sqlite3_free(zOpen);
2602   if( db ){
2603     assert( db->mutex!=0 || isThreadsafe==0 || sqlite3GlobalConfig.bFullMutex==0 );
2604     sqlite3_mutex_leave(db->mutex);
2605   }
2606   rc = sqlite3_errcode(db);
2607   assert( db!=0 || rc==SQLITE_NOMEM );
2608   if( rc==SQLITE_NOMEM ){
2609     sqlite3_close(db);
2610     db = 0;
2611   }else if( rc!=SQLITE_OK ){
2612     db->magic = SQLITE_MAGIC_SICK;
2613   }
2614   *ppDb = db;
2615 #ifdef SQLITE_ENABLE_SQLLOG
2616   if( sqlite3GlobalConfig.xSqllog ){
2617     /* Opening a db handle. Fourth parameter is passed 0. */
2618     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2619     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2620   }
2621 #endif
2622   return sqlite3ApiExit(0, rc);
2623 }
2624 
2625 /*
2626 ** Open a new database handle.
2627 */
2628 int sqlite3_open(
2629   const char *zFilename,
2630   sqlite3 **ppDb
2631 ){
2632   return openDatabase(zFilename, ppDb,
2633                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2634 }
2635 int sqlite3_open_v2(
2636   const char *filename,   /* Database filename (UTF-8) */
2637   sqlite3 **ppDb,         /* OUT: SQLite db handle */
2638   int flags,              /* Flags */
2639   const char *zVfs        /* Name of VFS module to use */
2640 ){
2641   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
2642 }
2643 
2644 #ifndef SQLITE_OMIT_UTF16
2645 /*
2646 ** Open a new database handle.
2647 */
2648 int sqlite3_open16(
2649   const void *zFilename,
2650   sqlite3 **ppDb
2651 ){
2652   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
2653   sqlite3_value *pVal;
2654   int rc;
2655 
2656   assert( zFilename );
2657   assert( ppDb );
2658   *ppDb = 0;
2659 #ifndef SQLITE_OMIT_AUTOINIT
2660   rc = sqlite3_initialize();
2661   if( rc ) return rc;
2662 #endif
2663   pVal = sqlite3ValueNew(0);
2664   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
2665   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
2666   if( zFilename8 ){
2667     rc = openDatabase(zFilename8, ppDb,
2668                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2669     assert( *ppDb || rc==SQLITE_NOMEM );
2670     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
2671       ENC(*ppDb) = SQLITE_UTF16NATIVE;
2672     }
2673   }else{
2674     rc = SQLITE_NOMEM;
2675   }
2676   sqlite3ValueFree(pVal);
2677 
2678   return sqlite3ApiExit(0, rc);
2679 }
2680 #endif /* SQLITE_OMIT_UTF16 */
2681 
2682 /*
2683 ** Register a new collation sequence with the database handle db.
2684 */
2685 int sqlite3_create_collation(
2686   sqlite3* db,
2687   const char *zName,
2688   int enc,
2689   void* pCtx,
2690   int(*xCompare)(void*,int,const void*,int,const void*)
2691 ){
2692   int rc;
2693   sqlite3_mutex_enter(db->mutex);
2694   assert( !db->mallocFailed );
2695   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, 0);
2696   rc = sqlite3ApiExit(db, rc);
2697   sqlite3_mutex_leave(db->mutex);
2698   return rc;
2699 }
2700 
2701 /*
2702 ** Register a new collation sequence with the database handle db.
2703 */
2704 int sqlite3_create_collation_v2(
2705   sqlite3* db,
2706   const char *zName,
2707   int enc,
2708   void* pCtx,
2709   int(*xCompare)(void*,int,const void*,int,const void*),
2710   void(*xDel)(void*)
2711 ){
2712   int rc;
2713   sqlite3_mutex_enter(db->mutex);
2714   assert( !db->mallocFailed );
2715   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
2716   rc = sqlite3ApiExit(db, rc);
2717   sqlite3_mutex_leave(db->mutex);
2718   return rc;
2719 }
2720 
2721 #ifndef SQLITE_OMIT_UTF16
2722 /*
2723 ** Register a new collation sequence with the database handle db.
2724 */
2725 int sqlite3_create_collation16(
2726   sqlite3* db,
2727   const void *zName,
2728   int enc,
2729   void* pCtx,
2730   int(*xCompare)(void*,int,const void*,int,const void*)
2731 ){
2732   int rc = SQLITE_OK;
2733   char *zName8;
2734   sqlite3_mutex_enter(db->mutex);
2735   assert( !db->mallocFailed );
2736   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
2737   if( zName8 ){
2738     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
2739     sqlite3DbFree(db, zName8);
2740   }
2741   rc = sqlite3ApiExit(db, rc);
2742   sqlite3_mutex_leave(db->mutex);
2743   return rc;
2744 }
2745 #endif /* SQLITE_OMIT_UTF16 */
2746 
2747 /*
2748 ** Register a collation sequence factory callback with the database handle
2749 ** db. Replace any previously installed collation sequence factory.
2750 */
2751 int sqlite3_collation_needed(
2752   sqlite3 *db,
2753   void *pCollNeededArg,
2754   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
2755 ){
2756   sqlite3_mutex_enter(db->mutex);
2757   db->xCollNeeded = xCollNeeded;
2758   db->xCollNeeded16 = 0;
2759   db->pCollNeededArg = pCollNeededArg;
2760   sqlite3_mutex_leave(db->mutex);
2761   return SQLITE_OK;
2762 }
2763 
2764 #ifndef SQLITE_OMIT_UTF16
2765 /*
2766 ** Register a collation sequence factory callback with the database handle
2767 ** db. Replace any previously installed collation sequence factory.
2768 */
2769 int sqlite3_collation_needed16(
2770   sqlite3 *db,
2771   void *pCollNeededArg,
2772   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
2773 ){
2774   sqlite3_mutex_enter(db->mutex);
2775   db->xCollNeeded = 0;
2776   db->xCollNeeded16 = xCollNeeded16;
2777   db->pCollNeededArg = pCollNeededArg;
2778   sqlite3_mutex_leave(db->mutex);
2779   return SQLITE_OK;
2780 }
2781 #endif /* SQLITE_OMIT_UTF16 */
2782 
2783 #ifndef SQLITE_OMIT_DEPRECATED
2784 /*
2785 ** This function is now an anachronism. It used to be used to recover from a
2786 ** malloc() failure, but SQLite now does this automatically.
2787 */
2788 int sqlite3_global_recover(void){
2789   return SQLITE_OK;
2790 }
2791 #endif
2792 
2793 /*
2794 ** Test to see whether or not the database connection is in autocommit
2795 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
2796 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
2797 ** by the next COMMIT or ROLLBACK.
2798 */
2799 int sqlite3_get_autocommit(sqlite3 *db){
2800   return db->autoCommit;
2801 }
2802 
2803 /*
2804 ** The following routines are subtitutes for constants SQLITE_CORRUPT,
2805 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
2806 ** constants.  They server two purposes:
2807 **
2808 **   1.  Serve as a convenient place to set a breakpoint in a debugger
2809 **       to detect when version error conditions occurs.
2810 **
2811 **   2.  Invoke sqlite3_log() to provide the source code location where
2812 **       a low-level error is first detected.
2813 */
2814 int sqlite3CorruptError(int lineno){
2815   testcase( sqlite3GlobalConfig.xLog!=0 );
2816   sqlite3_log(SQLITE_CORRUPT,
2817               "database corruption at line %d of [%.10s]",
2818               lineno, 20+sqlite3_sourceid());
2819   return SQLITE_CORRUPT;
2820 }
2821 int sqlite3MisuseError(int lineno){
2822   testcase( sqlite3GlobalConfig.xLog!=0 );
2823   sqlite3_log(SQLITE_MISUSE,
2824               "misuse at line %d of [%.10s]",
2825               lineno, 20+sqlite3_sourceid());
2826   return SQLITE_MISUSE;
2827 }
2828 int sqlite3CantopenError(int lineno){
2829   testcase( sqlite3GlobalConfig.xLog!=0 );
2830   sqlite3_log(SQLITE_CANTOPEN,
2831               "cannot open file at line %d of [%.10s]",
2832               lineno, 20+sqlite3_sourceid());
2833   return SQLITE_CANTOPEN;
2834 }
2835 
2836 
2837 #ifndef SQLITE_OMIT_DEPRECATED
2838 /*
2839 ** This is a convenience routine that makes sure that all thread-specific
2840 ** data for this thread has been deallocated.
2841 **
2842 ** SQLite no longer uses thread-specific data so this routine is now a
2843 ** no-op.  It is retained for historical compatibility.
2844 */
2845 void sqlite3_thread_cleanup(void){
2846 }
2847 #endif
2848 
2849 /*
2850 ** Return meta information about a specific column of a database table.
2851 ** See comment in sqlite3.h (sqlite.h.in) for details.
2852 */
2853 #ifdef SQLITE_ENABLE_COLUMN_METADATA
2854 int sqlite3_table_column_metadata(
2855   sqlite3 *db,                /* Connection handle */
2856   const char *zDbName,        /* Database name or NULL */
2857   const char *zTableName,     /* Table name */
2858   const char *zColumnName,    /* Column name */
2859   char const **pzDataType,    /* OUTPUT: Declared data type */
2860   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
2861   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
2862   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
2863   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
2864 ){
2865   int rc;
2866   char *zErrMsg = 0;
2867   Table *pTab = 0;
2868   Column *pCol = 0;
2869   int iCol;
2870 
2871   char const *zDataType = 0;
2872   char const *zCollSeq = 0;
2873   int notnull = 0;
2874   int primarykey = 0;
2875   int autoinc = 0;
2876 
2877   /* Ensure the database schema has been loaded */
2878   sqlite3_mutex_enter(db->mutex);
2879   sqlite3BtreeEnterAll(db);
2880   rc = sqlite3Init(db, &zErrMsg);
2881   if( SQLITE_OK!=rc ){
2882     goto error_out;
2883   }
2884 
2885   /* Locate the table in question */
2886   pTab = sqlite3FindTable(db, zTableName, zDbName);
2887   if( !pTab || pTab->pSelect ){
2888     pTab = 0;
2889     goto error_out;
2890   }
2891 
2892   /* Find the column for which info is requested */
2893   if( sqlite3IsRowid(zColumnName) ){
2894     iCol = pTab->iPKey;
2895     if( iCol>=0 ){
2896       pCol = &pTab->aCol[iCol];
2897     }
2898   }else{
2899     for(iCol=0; iCol<pTab->nCol; iCol++){
2900       pCol = &pTab->aCol[iCol];
2901       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
2902         break;
2903       }
2904     }
2905     if( iCol==pTab->nCol ){
2906       pTab = 0;
2907       goto error_out;
2908     }
2909   }
2910 
2911   /* The following block stores the meta information that will be returned
2912   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
2913   ** and autoinc. At this point there are two possibilities:
2914   **
2915   **     1. The specified column name was rowid", "oid" or "_rowid_"
2916   **        and there is no explicitly declared IPK column.
2917   **
2918   **     2. The table is not a view and the column name identified an
2919   **        explicitly declared column. Copy meta information from *pCol.
2920   */
2921   if( pCol ){
2922     zDataType = pCol->zType;
2923     zCollSeq = pCol->zColl;
2924     notnull = pCol->notNull!=0;
2925     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
2926     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
2927   }else{
2928     zDataType = "INTEGER";
2929     primarykey = 1;
2930   }
2931   if( !zCollSeq ){
2932     zCollSeq = "BINARY";
2933   }
2934 
2935 error_out:
2936   sqlite3BtreeLeaveAll(db);
2937 
2938   /* Whether the function call succeeded or failed, set the output parameters
2939   ** to whatever their local counterparts contain. If an error did occur,
2940   ** this has the effect of zeroing all output parameters.
2941   */
2942   if( pzDataType ) *pzDataType = zDataType;
2943   if( pzCollSeq ) *pzCollSeq = zCollSeq;
2944   if( pNotNull ) *pNotNull = notnull;
2945   if( pPrimaryKey ) *pPrimaryKey = primarykey;
2946   if( pAutoinc ) *pAutoinc = autoinc;
2947 
2948   if( SQLITE_OK==rc && !pTab ){
2949     sqlite3DbFree(db, zErrMsg);
2950     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
2951         zColumnName);
2952     rc = SQLITE_ERROR;
2953   }
2954   sqlite3Error(db, rc, (zErrMsg?"%s":0), zErrMsg);
2955   sqlite3DbFree(db, zErrMsg);
2956   rc = sqlite3ApiExit(db, rc);
2957   sqlite3_mutex_leave(db->mutex);
2958   return rc;
2959 }
2960 #endif
2961 
2962 /*
2963 ** Sleep for a little while.  Return the amount of time slept.
2964 */
2965 int sqlite3_sleep(int ms){
2966   sqlite3_vfs *pVfs;
2967   int rc;
2968   pVfs = sqlite3_vfs_find(0);
2969   if( pVfs==0 ) return 0;
2970 
2971   /* This function works in milliseconds, but the underlying OsSleep()
2972   ** API uses microseconds. Hence the 1000's.
2973   */
2974   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
2975   return rc;
2976 }
2977 
2978 /*
2979 ** Enable or disable the extended result codes.
2980 */
2981 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
2982   sqlite3_mutex_enter(db->mutex);
2983   db->errMask = onoff ? 0xffffffff : 0xff;
2984   sqlite3_mutex_leave(db->mutex);
2985   return SQLITE_OK;
2986 }
2987 
2988 /*
2989 ** Invoke the xFileControl method on a particular database.
2990 */
2991 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
2992   int rc = SQLITE_ERROR;
2993   Btree *pBtree;
2994 
2995   sqlite3_mutex_enter(db->mutex);
2996   pBtree = sqlite3DbNameToBtree(db, zDbName);
2997   if( pBtree ){
2998     Pager *pPager;
2999     sqlite3_file *fd;
3000     sqlite3BtreeEnter(pBtree);
3001     pPager = sqlite3BtreePager(pBtree);
3002     assert( pPager!=0 );
3003     fd = sqlite3PagerFile(pPager);
3004     assert( fd!=0 );
3005     if( op==SQLITE_FCNTL_FILE_POINTER ){
3006       *(sqlite3_file**)pArg = fd;
3007       rc = SQLITE_OK;
3008     }else if( fd->pMethods ){
3009       rc = sqlite3OsFileControl(fd, op, pArg);
3010     }else{
3011       rc = SQLITE_NOTFOUND;
3012     }
3013     sqlite3BtreeLeave(pBtree);
3014   }
3015   sqlite3_mutex_leave(db->mutex);
3016   return rc;
3017 }
3018 
3019 /*
3020 ** Interface to the testing logic.
3021 */
3022 int sqlite3_test_control(int op, ...){
3023   int rc = 0;
3024 #ifndef SQLITE_OMIT_BUILTIN_TEST
3025   va_list ap;
3026   va_start(ap, op);
3027   switch( op ){
3028 
3029     /*
3030     ** Save the current state of the PRNG.
3031     */
3032     case SQLITE_TESTCTRL_PRNG_SAVE: {
3033       sqlite3PrngSaveState();
3034       break;
3035     }
3036 
3037     /*
3038     ** Restore the state of the PRNG to the last state saved using
3039     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3040     ** this verb acts like PRNG_RESET.
3041     */
3042     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3043       sqlite3PrngRestoreState();
3044       break;
3045     }
3046 
3047     /*
3048     ** Reset the PRNG back to its uninitialized state.  The next call
3049     ** to sqlite3_randomness() will reseed the PRNG using a single call
3050     ** to the xRandomness method of the default VFS.
3051     */
3052     case SQLITE_TESTCTRL_PRNG_RESET: {
3053       sqlite3PrngResetState();
3054       break;
3055     }
3056 
3057     /*
3058     **  sqlite3_test_control(BITVEC_TEST, size, program)
3059     **
3060     ** Run a test against a Bitvec object of size.  The program argument
3061     ** is an array of integers that defines the test.  Return -1 on a
3062     ** memory allocation error, 0 on success, or non-zero for an error.
3063     ** See the sqlite3BitvecBuiltinTest() for additional information.
3064     */
3065     case SQLITE_TESTCTRL_BITVEC_TEST: {
3066       int sz = va_arg(ap, int);
3067       int *aProg = va_arg(ap, int*);
3068       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3069       break;
3070     }
3071 
3072     /*
3073     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3074     **
3075     ** Register hooks to call to indicate which malloc() failures
3076     ** are benign.
3077     */
3078     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3079       typedef void (*void_function)(void);
3080       void_function xBenignBegin;
3081       void_function xBenignEnd;
3082       xBenignBegin = va_arg(ap, void_function);
3083       xBenignEnd = va_arg(ap, void_function);
3084       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3085       break;
3086     }
3087 
3088     /*
3089     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3090     **
3091     ** Set the PENDING byte to the value in the argument, if X>0.
3092     ** Make no changes if X==0.  Return the value of the pending byte
3093     ** as it existing before this routine was called.
3094     **
3095     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3096     ** an incompatible database file format.  Changing the PENDING byte
3097     ** while any database connection is open results in undefined and
3098     ** dileterious behavior.
3099     */
3100     case SQLITE_TESTCTRL_PENDING_BYTE: {
3101       rc = PENDING_BYTE;
3102 #ifndef SQLITE_OMIT_WSD
3103       {
3104         unsigned int newVal = va_arg(ap, unsigned int);
3105         if( newVal ) sqlite3PendingByte = newVal;
3106       }
3107 #endif
3108       break;
3109     }
3110 
3111     /*
3112     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3113     **
3114     ** This action provides a run-time test to see whether or not
3115     ** assert() was enabled at compile-time.  If X is true and assert()
3116     ** is enabled, then the return value is true.  If X is true and
3117     ** assert() is disabled, then the return value is zero.  If X is
3118     ** false and assert() is enabled, then the assertion fires and the
3119     ** process aborts.  If X is false and assert() is disabled, then the
3120     ** return value is zero.
3121     */
3122     case SQLITE_TESTCTRL_ASSERT: {
3123       volatile int x = 0;
3124       assert( (x = va_arg(ap,int))!=0 );
3125       rc = x;
3126       break;
3127     }
3128 
3129 
3130     /*
3131     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3132     **
3133     ** This action provides a run-time test to see how the ALWAYS and
3134     ** NEVER macros were defined at compile-time.
3135     **
3136     ** The return value is ALWAYS(X).
3137     **
3138     ** The recommended test is X==2.  If the return value is 2, that means
3139     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3140     ** default setting.  If the return value is 1, then ALWAYS() is either
3141     ** hard-coded to true or else it asserts if its argument is false.
3142     ** The first behavior (hard-coded to true) is the case if
3143     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3144     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3145     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3146     **
3147     ** The run-time test procedure might look something like this:
3148     **
3149     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3150     **      // ALWAYS() and NEVER() are no-op pass-through macros
3151     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3152     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3153     **    }else{
3154     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3155     **    }
3156     */
3157     case SQLITE_TESTCTRL_ALWAYS: {
3158       int x = va_arg(ap,int);
3159       rc = ALWAYS(x);
3160       break;
3161     }
3162 
3163     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3164     **
3165     ** Set the nReserve size to N for the main database on the database
3166     ** connection db.
3167     */
3168     case SQLITE_TESTCTRL_RESERVE: {
3169       sqlite3 *db = va_arg(ap, sqlite3*);
3170       int x = va_arg(ap,int);
3171       sqlite3_mutex_enter(db->mutex);
3172       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3173       sqlite3_mutex_leave(db->mutex);
3174       break;
3175     }
3176 
3177     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3178     **
3179     ** Enable or disable various optimizations for testing purposes.  The
3180     ** argument N is a bitmask of optimizations to be disabled.  For normal
3181     ** operation N should be 0.  The idea is that a test program (like the
3182     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3183     ** with various optimizations disabled to verify that the same answer
3184     ** is obtained in every case.
3185     */
3186     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3187       sqlite3 *db = va_arg(ap, sqlite3*);
3188       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3189       break;
3190     }
3191 
3192 #ifdef SQLITE_N_KEYWORD
3193     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3194     **
3195     ** If zWord is a keyword recognized by the parser, then return the
3196     ** number of keywords.  Or if zWord is not a keyword, return 0.
3197     **
3198     ** This test feature is only available in the amalgamation since
3199     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3200     ** is built using separate source files.
3201     */
3202     case SQLITE_TESTCTRL_ISKEYWORD: {
3203       const char *zWord = va_arg(ap, const char*);
3204       int n = sqlite3Strlen30(zWord);
3205       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3206       break;
3207     }
3208 #endif
3209 
3210     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3211     **
3212     ** Pass pFree into sqlite3ScratchFree().
3213     ** If sz>0 then allocate a scratch buffer into pNew.
3214     */
3215     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3216       void *pFree, **ppNew;
3217       int sz;
3218       sz = va_arg(ap, int);
3219       ppNew = va_arg(ap, void**);
3220       pFree = va_arg(ap, void*);
3221       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3222       sqlite3ScratchFree(pFree);
3223       break;
3224     }
3225 
3226     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3227     **
3228     ** If parameter onoff is non-zero, configure the wrappers so that all
3229     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3230     ** undo this setting.
3231     */
3232     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3233       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3234       break;
3235     }
3236 
3237 #if defined(SQLITE_ENABLE_TREE_EXPLAIN)
3238     /*   sqlite3_test_control(SQLITE_TESTCTRL_EXPLAIN_STMT,
3239     **                        sqlite3_stmt*,const char**);
3240     **
3241     ** If compiled with SQLITE_ENABLE_TREE_EXPLAIN, each sqlite3_stmt holds
3242     ** a string that describes the optimized parse tree.  This test-control
3243     ** returns a pointer to that string.
3244     */
3245     case SQLITE_TESTCTRL_EXPLAIN_STMT: {
3246       sqlite3_stmt *pStmt = va_arg(ap, sqlite3_stmt*);
3247       const char **pzRet = va_arg(ap, const char**);
3248       *pzRet = sqlite3VdbeExplanation((Vdbe*)pStmt);
3249       break;
3250     }
3251 #endif
3252 
3253   }
3254   va_end(ap);
3255 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3256   return rc;
3257 }
3258 
3259 /*
3260 ** This is a utility routine, useful to VFS implementations, that checks
3261 ** to see if a database file was a URI that contained a specific query
3262 ** parameter, and if so obtains the value of the query parameter.
3263 **
3264 ** The zFilename argument is the filename pointer passed into the xOpen()
3265 ** method of a VFS implementation.  The zParam argument is the name of the
3266 ** query parameter we seek.  This routine returns the value of the zParam
3267 ** parameter if it exists.  If the parameter does not exist, this routine
3268 ** returns a NULL pointer.
3269 */
3270 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3271   if( zFilename==0 ) return 0;
3272   zFilename += sqlite3Strlen30(zFilename) + 1;
3273   while( zFilename[0] ){
3274     int x = strcmp(zFilename, zParam);
3275     zFilename += sqlite3Strlen30(zFilename) + 1;
3276     if( x==0 ) return zFilename;
3277     zFilename += sqlite3Strlen30(zFilename) + 1;
3278   }
3279   return 0;
3280 }
3281 
3282 /*
3283 ** Return a boolean value for a query parameter.
3284 */
3285 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3286   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3287   bDflt = bDflt!=0;
3288   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3289 }
3290 
3291 /*
3292 ** Return a 64-bit integer value for a query parameter.
3293 */
3294 sqlite3_int64 sqlite3_uri_int64(
3295   const char *zFilename,    /* Filename as passed to xOpen */
3296   const char *zParam,       /* URI parameter sought */
3297   sqlite3_int64 bDflt       /* return if parameter is missing */
3298 ){
3299   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3300   sqlite3_int64 v;
3301   if( z && sqlite3Atoi64(z, &v, sqlite3Strlen30(z), SQLITE_UTF8)==SQLITE_OK ){
3302     bDflt = v;
3303   }
3304   return bDflt;
3305 }
3306 
3307 /*
3308 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3309 */
3310 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3311   int i;
3312   for(i=0; i<db->nDb; i++){
3313     if( db->aDb[i].pBt
3314      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3315     ){
3316       return db->aDb[i].pBt;
3317     }
3318   }
3319   return 0;
3320 }
3321 
3322 /*
3323 ** Return the filename of the database associated with a database
3324 ** connection.
3325 */
3326 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3327   Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
3328   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3329 }
3330 
3331 /*
3332 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3333 ** no such database exists.
3334 */
3335 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3336   Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
3337   return pBt ? sqlite3PagerIsreadonly(sqlite3BtreePager(pBt)) : -1;
3338 }
3339