xref: /sqlite-3.40.0/src/main.c (revision cc285c5a)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Main file for the SQLite library.  The routines in this file
13 ** implement the programmer interface to the library.  Routines in
14 ** other files are for internal use by SQLite and should not be
15 ** accessed by users of the library.
16 */
17 #include "sqliteInt.h"
18 
19 #ifdef SQLITE_ENABLE_FTS3
20 # include "fts3.h"
21 #endif
22 #ifdef SQLITE_ENABLE_RTREE
23 # include "rtree.h"
24 #endif
25 #ifdef SQLITE_ENABLE_ICU
26 # include "sqliteicu.h"
27 #endif
28 
29 #ifndef SQLITE_AMALGAMATION
30 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
31 ** contains the text of SQLITE_VERSION macro.
32 */
33 const char sqlite3_version[] = SQLITE_VERSION;
34 #endif
35 
36 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
37 ** a pointer to the to the sqlite3_version[] string constant.
38 */
39 const char *sqlite3_libversion(void){ return sqlite3_version; }
40 
41 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
42 ** pointer to a string constant whose value is the same as the
43 ** SQLITE_SOURCE_ID C preprocessor macro.
44 */
45 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
46 
47 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
48 ** returns an integer equal to SQLITE_VERSION_NUMBER.
49 */
50 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
51 
52 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
53 ** zero if and only if SQLite was compiled with mutexing code omitted due to
54 ** the SQLITE_THREADSAFE compile-time option being set to 0.
55 */
56 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
57 
58 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
59 /*
60 ** If the following function pointer is not NULL and if
61 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
62 ** I/O active are written using this function.  These messages
63 ** are intended for debugging activity only.
64 */
65 /* not-private */ void (*sqlite3IoTrace)(const char*, ...) = 0;
66 #endif
67 
68 /*
69 ** If the following global variable points to a string which is the
70 ** name of a directory, then that directory will be used to store
71 ** temporary files.
72 **
73 ** See also the "PRAGMA temp_store_directory" SQL command.
74 */
75 char *sqlite3_temp_directory = 0;
76 
77 /*
78 ** If the following global variable points to a string which is the
79 ** name of a directory, then that directory will be used to store
80 ** all database files specified with a relative pathname.
81 **
82 ** See also the "PRAGMA data_store_directory" SQL command.
83 */
84 char *sqlite3_data_directory = 0;
85 
86 /*
87 ** Initialize SQLite.
88 **
89 ** This routine must be called to initialize the memory allocation,
90 ** VFS, and mutex subsystems prior to doing any serious work with
91 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
92 ** this routine will be called automatically by key routines such as
93 ** sqlite3_open().
94 **
95 ** This routine is a no-op except on its very first call for the process,
96 ** or for the first call after a call to sqlite3_shutdown.
97 **
98 ** The first thread to call this routine runs the initialization to
99 ** completion.  If subsequent threads call this routine before the first
100 ** thread has finished the initialization process, then the subsequent
101 ** threads must block until the first thread finishes with the initialization.
102 **
103 ** The first thread might call this routine recursively.  Recursive
104 ** calls to this routine should not block, of course.  Otherwise the
105 ** initialization process would never complete.
106 **
107 ** Let X be the first thread to enter this routine.  Let Y be some other
108 ** thread.  Then while the initial invocation of this routine by X is
109 ** incomplete, it is required that:
110 **
111 **    *  Calls to this routine from Y must block until the outer-most
112 **       call by X completes.
113 **
114 **    *  Recursive calls to this routine from thread X return immediately
115 **       without blocking.
116 */
117 int sqlite3_initialize(void){
118   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
119   int rc;                                      /* Result code */
120 #ifdef SQLITE_EXTRA_INIT
121   int bRunExtraInit = 0;                       /* Extra initialization needed */
122 #endif
123 
124 #ifdef SQLITE_OMIT_WSD
125   rc = sqlite3_wsd_init(4096, 24);
126   if( rc!=SQLITE_OK ){
127     return rc;
128   }
129 #endif
130 
131   /* If SQLite is already completely initialized, then this call
132   ** to sqlite3_initialize() should be a no-op.  But the initialization
133   ** must be complete.  So isInit must not be set until the very end
134   ** of this routine.
135   */
136   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
137 
138   /* Make sure the mutex subsystem is initialized.  If unable to
139   ** initialize the mutex subsystem, return early with the error.
140   ** If the system is so sick that we are unable to allocate a mutex,
141   ** there is not much SQLite is going to be able to do.
142   **
143   ** The mutex subsystem must take care of serializing its own
144   ** initialization.
145   */
146   rc = sqlite3MutexInit();
147   if( rc ) return rc;
148 
149   /* Initialize the malloc() system and the recursive pInitMutex mutex.
150   ** This operation is protected by the STATIC_MASTER mutex.  Note that
151   ** MutexAlloc() is called for a static mutex prior to initializing the
152   ** malloc subsystem - this implies that the allocation of a static
153   ** mutex must not require support from the malloc subsystem.
154   */
155   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
156   sqlite3_mutex_enter(pMaster);
157   sqlite3GlobalConfig.isMutexInit = 1;
158   if( !sqlite3GlobalConfig.isMallocInit ){
159     rc = sqlite3MallocInit();
160   }
161   if( rc==SQLITE_OK ){
162     sqlite3GlobalConfig.isMallocInit = 1;
163     if( !sqlite3GlobalConfig.pInitMutex ){
164       sqlite3GlobalConfig.pInitMutex =
165            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
166       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
167         rc = SQLITE_NOMEM;
168       }
169     }
170   }
171   if( rc==SQLITE_OK ){
172     sqlite3GlobalConfig.nRefInitMutex++;
173   }
174   sqlite3_mutex_leave(pMaster);
175 
176   /* If rc is not SQLITE_OK at this point, then either the malloc
177   ** subsystem could not be initialized or the system failed to allocate
178   ** the pInitMutex mutex. Return an error in either case.  */
179   if( rc!=SQLITE_OK ){
180     return rc;
181   }
182 
183   /* Do the rest of the initialization under the recursive mutex so
184   ** that we will be able to handle recursive calls into
185   ** sqlite3_initialize().  The recursive calls normally come through
186   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
187   ** recursive calls might also be possible.
188   **
189   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
190   ** to the xInit method, so the xInit method need not be threadsafe.
191   **
192   ** The following mutex is what serializes access to the appdef pcache xInit
193   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
194   ** call to sqlite3PcacheInitialize().
195   */
196   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
197   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
198     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
199     sqlite3GlobalConfig.inProgress = 1;
200     memset(pHash, 0, sizeof(sqlite3GlobalFunctions));
201     sqlite3RegisterGlobalFunctions();
202     if( sqlite3GlobalConfig.isPCacheInit==0 ){
203       rc = sqlite3PcacheInitialize();
204     }
205     if( rc==SQLITE_OK ){
206       sqlite3GlobalConfig.isPCacheInit = 1;
207       rc = sqlite3OsInit();
208     }
209     if( rc==SQLITE_OK ){
210       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
211           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
212       sqlite3GlobalConfig.isInit = 1;
213 #ifdef SQLITE_EXTRA_INIT
214       bRunExtraInit = 1;
215 #endif
216     }
217     sqlite3GlobalConfig.inProgress = 0;
218   }
219   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
220 
221   /* Go back under the static mutex and clean up the recursive
222   ** mutex to prevent a resource leak.
223   */
224   sqlite3_mutex_enter(pMaster);
225   sqlite3GlobalConfig.nRefInitMutex--;
226   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
227     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
228     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
229     sqlite3GlobalConfig.pInitMutex = 0;
230   }
231   sqlite3_mutex_leave(pMaster);
232 
233   /* The following is just a sanity check to make sure SQLite has
234   ** been compiled correctly.  It is important to run this code, but
235   ** we don't want to run it too often and soak up CPU cycles for no
236   ** reason.  So we run it once during initialization.
237   */
238 #ifndef NDEBUG
239 #ifndef SQLITE_OMIT_FLOATING_POINT
240   /* This section of code's only "output" is via assert() statements. */
241   if ( rc==SQLITE_OK ){
242     u64 x = (((u64)1)<<63)-1;
243     double y;
244     assert(sizeof(x)==8);
245     assert(sizeof(x)==sizeof(y));
246     memcpy(&y, &x, 8);
247     assert( sqlite3IsNaN(y) );
248   }
249 #endif
250 #endif
251 
252   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
253   ** compile-time option.
254   */
255 #ifdef SQLITE_EXTRA_INIT
256   if( bRunExtraInit ){
257     int SQLITE_EXTRA_INIT(const char*);
258     rc = SQLITE_EXTRA_INIT(0);
259   }
260 #endif
261 
262   return rc;
263 }
264 
265 /*
266 ** Undo the effects of sqlite3_initialize().  Must not be called while
267 ** there are outstanding database connections or memory allocations or
268 ** while any part of SQLite is otherwise in use in any thread.  This
269 ** routine is not threadsafe.  But it is safe to invoke this routine
270 ** on when SQLite is already shut down.  If SQLite is already shut down
271 ** when this routine is invoked, then this routine is a harmless no-op.
272 */
273 int sqlite3_shutdown(void){
274 #ifdef SQLITE_OMIT_WSD
275   int rc = sqlite3_wsd_init(4096, 24);
276   if( rc!=SQLITE_OK ){
277     return rc;
278   }
279 #endif
280 
281   if( sqlite3GlobalConfig.isInit ){
282 #ifdef SQLITE_EXTRA_SHUTDOWN
283     void SQLITE_EXTRA_SHUTDOWN(void);
284     SQLITE_EXTRA_SHUTDOWN();
285 #endif
286     sqlite3_os_end();
287     sqlite3_reset_auto_extension();
288     sqlite3GlobalConfig.isInit = 0;
289   }
290   if( sqlite3GlobalConfig.isPCacheInit ){
291     sqlite3PcacheShutdown();
292     sqlite3GlobalConfig.isPCacheInit = 0;
293   }
294   if( sqlite3GlobalConfig.isMallocInit ){
295     sqlite3MallocEnd();
296     sqlite3GlobalConfig.isMallocInit = 0;
297 
298 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
299     /* The heap subsystem has now been shutdown and these values are supposed
300     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
301     ** which would rely on that heap subsystem; therefore, make sure these
302     ** values cannot refer to heap memory that was just invalidated when the
303     ** heap subsystem was shutdown.  This is only done if the current call to
304     ** this function resulted in the heap subsystem actually being shutdown.
305     */
306     sqlite3_data_directory = 0;
307     sqlite3_temp_directory = 0;
308 #endif
309   }
310   if( sqlite3GlobalConfig.isMutexInit ){
311     sqlite3MutexEnd();
312     sqlite3GlobalConfig.isMutexInit = 0;
313   }
314 
315   return SQLITE_OK;
316 }
317 
318 /*
319 ** This API allows applications to modify the global configuration of
320 ** the SQLite library at run-time.
321 **
322 ** This routine should only be called when there are no outstanding
323 ** database connections or memory allocations.  This routine is not
324 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
325 ** behavior.
326 */
327 int sqlite3_config(int op, ...){
328   va_list ap;
329   int rc = SQLITE_OK;
330 
331   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
332   ** the SQLite library is in use. */
333   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
334 
335   va_start(ap, op);
336   switch( op ){
337 
338     /* Mutex configuration options are only available in a threadsafe
339     ** compile.
340     */
341 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
342     case SQLITE_CONFIG_SINGLETHREAD: {
343       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
344       ** Single-thread. */
345       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
346       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
347       break;
348     }
349 #endif
350 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
351     case SQLITE_CONFIG_MULTITHREAD: {
352       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
353       ** Multi-thread. */
354       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
355       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
356       break;
357     }
358 #endif
359 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
360     case SQLITE_CONFIG_SERIALIZED: {
361       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
362       ** Serialized. */
363       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
364       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
365       break;
366     }
367 #endif
368 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
369     case SQLITE_CONFIG_MUTEX: {
370       /* Specify an alternative mutex implementation */
371       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
372       break;
373     }
374 #endif
375 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
376     case SQLITE_CONFIG_GETMUTEX: {
377       /* Retrieve the current mutex implementation */
378       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
379       break;
380     }
381 #endif
382 
383     case SQLITE_CONFIG_MALLOC: {
384       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
385       ** single argument which is a pointer to an instance of the
386       ** sqlite3_mem_methods structure. The argument specifies alternative
387       ** low-level memory allocation routines to be used in place of the memory
388       ** allocation routines built into SQLite. */
389       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
390       break;
391     }
392     case SQLITE_CONFIG_GETMALLOC: {
393       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
394       ** single argument which is a pointer to an instance of the
395       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
396       ** filled with the currently defined memory allocation routines. */
397       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
398       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
399       break;
400     }
401     case SQLITE_CONFIG_MEMSTATUS: {
402       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
403       ** single argument of type int, interpreted as a boolean, which enables
404       ** or disables the collection of memory allocation statistics. */
405       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
406       break;
407     }
408     case SQLITE_CONFIG_SCRATCH: {
409       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
410       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
411       ** which the scratch allocations will be drawn, the size of each scratch
412       ** allocation (sz), and the maximum number of scratch allocations (N). */
413       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
414       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
415       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
416       break;
417     }
418     case SQLITE_CONFIG_PAGECACHE: {
419       /* EVIDENCE-OF: R-31408-40510 There are three arguments to
420       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory, the size
421       ** of each page buffer (sz), and the number of pages (N). */
422       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
423       sqlite3GlobalConfig.szPage = va_arg(ap, int);
424       sqlite3GlobalConfig.nPage = va_arg(ap, int);
425       break;
426     }
427     case SQLITE_CONFIG_PCACHE_HDRSZ: {
428       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
429       ** a single parameter which is a pointer to an integer and writes into
430       ** that integer the number of extra bytes per page required for each page
431       ** in SQLITE_CONFIG_PAGECACHE. */
432       *va_arg(ap, int*) =
433           sqlite3HeaderSizeBtree() +
434           sqlite3HeaderSizePcache() +
435           sqlite3HeaderSizePcache1();
436       break;
437     }
438 
439     case SQLITE_CONFIG_PCACHE: {
440       /* no-op */
441       break;
442     }
443     case SQLITE_CONFIG_GETPCACHE: {
444       /* now an error */
445       rc = SQLITE_ERROR;
446       break;
447     }
448 
449     case SQLITE_CONFIG_PCACHE2: {
450       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
451       ** single argument which is a pointer to an sqlite3_pcache_methods2
452       ** object. This object specifies the interface to a custom page cache
453       ** implementation. */
454       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
455       break;
456     }
457     case SQLITE_CONFIG_GETPCACHE2: {
458       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
459       ** single argument which is a pointer to an sqlite3_pcache_methods2
460       ** object. SQLite copies of the current page cache implementation into
461       ** that object. */
462       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
463         sqlite3PCacheSetDefault();
464       }
465       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
466       break;
467     }
468 
469 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
470 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
471 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
472 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
473     case SQLITE_CONFIG_HEAP: {
474       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
475       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
476       ** number of bytes in the memory buffer, and the minimum allocation size.
477       */
478       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
479       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
480       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
481 
482       if( sqlite3GlobalConfig.mnReq<1 ){
483         sqlite3GlobalConfig.mnReq = 1;
484       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
485         /* cap min request size at 2^12 */
486         sqlite3GlobalConfig.mnReq = (1<<12);
487       }
488 
489       if( sqlite3GlobalConfig.pHeap==0 ){
490         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
491         ** is NULL, then SQLite reverts to using its default memory allocator
492         ** (the system malloc() implementation), undoing any prior invocation of
493         ** SQLITE_CONFIG_MALLOC.
494         **
495         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
496         ** revert to its default implementation when sqlite3_initialize() is run
497         */
498         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
499       }else{
500         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
501         ** alternative memory allocator is engaged to handle all of SQLites
502         ** memory allocation needs. */
503 #ifdef SQLITE_ENABLE_MEMSYS3
504         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
505 #endif
506 #ifdef SQLITE_ENABLE_MEMSYS5
507         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
508 #endif
509       }
510       break;
511     }
512 #endif
513 
514     case SQLITE_CONFIG_LOOKASIDE: {
515       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
516       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
517       break;
518     }
519 
520     /* Record a pointer to the logger function and its first argument.
521     ** The default is NULL.  Logging is disabled if the function pointer is
522     ** NULL.
523     */
524     case SQLITE_CONFIG_LOG: {
525       /* MSVC is picky about pulling func ptrs from va lists.
526       ** http://support.microsoft.com/kb/47961
527       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
528       */
529       typedef void(*LOGFUNC_t)(void*,int,const char*);
530       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
531       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
532       break;
533     }
534 
535     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
536     ** can be changed at start-time using the
537     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
538     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
539     */
540     case SQLITE_CONFIG_URI: {
541       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
542       ** argument of type int. If non-zero, then URI handling is globally
543       ** enabled. If the parameter is zero, then URI handling is globally
544       ** disabled. */
545       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
546       break;
547     }
548 
549     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
550       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
551       ** option takes a single integer argument which is interpreted as a
552       ** boolean in order to enable or disable the use of covering indices for
553       ** full table scans in the query optimizer. */
554       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
555       break;
556     }
557 
558 #ifdef SQLITE_ENABLE_SQLLOG
559     case SQLITE_CONFIG_SQLLOG: {
560       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
561       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
562       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
563       break;
564     }
565 #endif
566 
567     case SQLITE_CONFIG_MMAP_SIZE: {
568       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
569       ** integer (sqlite3_int64) values that are the default mmap size limit
570       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
571       ** mmap size limit. */
572       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
573       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
574       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
575       ** negative, then that argument is changed to its compile-time default.
576       **
577       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
578       ** silently truncated if necessary so that it does not exceed the
579       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
580       ** compile-time option.
581       */
582       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
583         mxMmap = SQLITE_MAX_MMAP_SIZE;
584       }
585       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
586       if( szMmap>mxMmap) szMmap = mxMmap;
587       sqlite3GlobalConfig.mxMmap = mxMmap;
588       sqlite3GlobalConfig.szMmap = szMmap;
589       break;
590     }
591 
592 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
593     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
594       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
595       ** unsigned integer value that specifies the maximum size of the created
596       ** heap. */
597       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
598       break;
599     }
600 #endif
601 
602     case SQLITE_CONFIG_PMASZ: {
603       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
604       break;
605     }
606 
607     default: {
608       rc = SQLITE_ERROR;
609       break;
610     }
611   }
612   va_end(ap);
613   return rc;
614 }
615 
616 /*
617 ** Set up the lookaside buffers for a database connection.
618 ** Return SQLITE_OK on success.
619 ** If lookaside is already active, return SQLITE_BUSY.
620 **
621 ** The sz parameter is the number of bytes in each lookaside slot.
622 ** The cnt parameter is the number of slots.  If pStart is NULL the
623 ** space for the lookaside memory is obtained from sqlite3_malloc().
624 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
625 ** the lookaside memory.
626 */
627 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
628   void *pStart;
629   if( db->lookaside.nOut ){
630     return SQLITE_BUSY;
631   }
632   /* Free any existing lookaside buffer for this handle before
633   ** allocating a new one so we don't have to have space for
634   ** both at the same time.
635   */
636   if( db->lookaside.bMalloced ){
637     sqlite3_free(db->lookaside.pStart);
638   }
639   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
640   ** than a pointer to be useful.
641   */
642   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
643   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
644   if( cnt<0 ) cnt = 0;
645   if( sz==0 || cnt==0 ){
646     sz = 0;
647     pStart = 0;
648   }else if( pBuf==0 ){
649     sqlite3BeginBenignMalloc();
650     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
651     sqlite3EndBenignMalloc();
652     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
653   }else{
654     pStart = pBuf;
655   }
656   db->lookaside.pStart = pStart;
657   db->lookaside.pFree = 0;
658   db->lookaside.sz = (u16)sz;
659   if( pStart ){
660     int i;
661     LookasideSlot *p;
662     assert( sz > (int)sizeof(LookasideSlot*) );
663     p = (LookasideSlot*)pStart;
664     for(i=cnt-1; i>=0; i--){
665       p->pNext = db->lookaside.pFree;
666       db->lookaside.pFree = p;
667       p = (LookasideSlot*)&((u8*)p)[sz];
668     }
669     db->lookaside.pEnd = p;
670     db->lookaside.bEnabled = 1;
671     db->lookaside.bMalloced = pBuf==0 ?1:0;
672   }else{
673     db->lookaside.pStart = db;
674     db->lookaside.pEnd = db;
675     db->lookaside.bEnabled = 0;
676     db->lookaside.bMalloced = 0;
677   }
678   return SQLITE_OK;
679 }
680 
681 /*
682 ** Return the mutex associated with a database connection.
683 */
684 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
685 #ifdef SQLITE_ENABLE_API_ARMOR
686   if( !sqlite3SafetyCheckOk(db) ){
687     (void)SQLITE_MISUSE_BKPT;
688     return 0;
689   }
690 #endif
691   return db->mutex;
692 }
693 
694 /*
695 ** Free up as much memory as we can from the given database
696 ** connection.
697 */
698 int sqlite3_db_release_memory(sqlite3 *db){
699   int i;
700 
701 #ifdef SQLITE_ENABLE_API_ARMOR
702   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
703 #endif
704   sqlite3_mutex_enter(db->mutex);
705   sqlite3BtreeEnterAll(db);
706   for(i=0; i<db->nDb; i++){
707     Btree *pBt = db->aDb[i].pBt;
708     if( pBt ){
709       Pager *pPager = sqlite3BtreePager(pBt);
710       sqlite3PagerShrink(pPager);
711     }
712   }
713   sqlite3BtreeLeaveAll(db);
714   sqlite3_mutex_leave(db->mutex);
715   return SQLITE_OK;
716 }
717 
718 /*
719 ** Configuration settings for an individual database connection
720 */
721 int sqlite3_db_config(sqlite3 *db, int op, ...){
722   va_list ap;
723   int rc;
724   va_start(ap, op);
725   switch( op ){
726     case SQLITE_DBCONFIG_LOOKASIDE: {
727       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
728       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
729       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
730       rc = setupLookaside(db, pBuf, sz, cnt);
731       break;
732     }
733     default: {
734       static const struct {
735         int op;      /* The opcode */
736         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
737       } aFlagOp[] = {
738         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
739         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
740       };
741       unsigned int i;
742       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
743       for(i=0; i<ArraySize(aFlagOp); i++){
744         if( aFlagOp[i].op==op ){
745           int onoff = va_arg(ap, int);
746           int *pRes = va_arg(ap, int*);
747           int oldFlags = db->flags;
748           if( onoff>0 ){
749             db->flags |= aFlagOp[i].mask;
750           }else if( onoff==0 ){
751             db->flags &= ~aFlagOp[i].mask;
752           }
753           if( oldFlags!=db->flags ){
754             sqlite3ExpirePreparedStatements(db);
755           }
756           if( pRes ){
757             *pRes = (db->flags & aFlagOp[i].mask)!=0;
758           }
759           rc = SQLITE_OK;
760           break;
761         }
762       }
763       break;
764     }
765   }
766   va_end(ap);
767   return rc;
768 }
769 
770 
771 /*
772 ** Return true if the buffer z[0..n-1] contains all spaces.
773 */
774 static int allSpaces(const char *z, int n){
775   while( n>0 && z[n-1]==' ' ){ n--; }
776   return n==0;
777 }
778 
779 /*
780 ** This is the default collating function named "BINARY" which is always
781 ** available.
782 **
783 ** If the padFlag argument is not NULL then space padding at the end
784 ** of strings is ignored.  This implements the RTRIM collation.
785 */
786 static int binCollFunc(
787   void *padFlag,
788   int nKey1, const void *pKey1,
789   int nKey2, const void *pKey2
790 ){
791   int rc, n;
792   n = nKey1<nKey2 ? nKey1 : nKey2;
793   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
794   ** strings byte by byte using the memcmp() function from the standard C
795   ** library. */
796   rc = memcmp(pKey1, pKey2, n);
797   if( rc==0 ){
798     if( padFlag
799      && allSpaces(((char*)pKey1)+n, nKey1-n)
800      && allSpaces(((char*)pKey2)+n, nKey2-n)
801     ){
802       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
803       ** spaces at the end of either string do not change the result. In other
804       ** words, strings will compare equal to one another as long as they
805       ** differ only in the number of spaces at the end.
806       */
807     }else{
808       rc = nKey1 - nKey2;
809     }
810   }
811   return rc;
812 }
813 
814 /*
815 ** Another built-in collating sequence: NOCASE.
816 **
817 ** This collating sequence is intended to be used for "case independent
818 ** comparison". SQLite's knowledge of upper and lower case equivalents
819 ** extends only to the 26 characters used in the English language.
820 **
821 ** At the moment there is only a UTF-8 implementation.
822 */
823 static int nocaseCollatingFunc(
824   void *NotUsed,
825   int nKey1, const void *pKey1,
826   int nKey2, const void *pKey2
827 ){
828   int r = sqlite3StrNICmp(
829       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
830   UNUSED_PARAMETER(NotUsed);
831   if( 0==r ){
832     r = nKey1-nKey2;
833   }
834   return r;
835 }
836 
837 /*
838 ** Return the ROWID of the most recent insert
839 */
840 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
841 #ifdef SQLITE_ENABLE_API_ARMOR
842   if( !sqlite3SafetyCheckOk(db) ){
843     (void)SQLITE_MISUSE_BKPT;
844     return 0;
845   }
846 #endif
847   return db->lastRowid;
848 }
849 
850 /*
851 ** Return the number of changes in the most recent call to sqlite3_exec().
852 */
853 int sqlite3_changes(sqlite3 *db){
854 #ifdef SQLITE_ENABLE_API_ARMOR
855   if( !sqlite3SafetyCheckOk(db) ){
856     (void)SQLITE_MISUSE_BKPT;
857     return 0;
858   }
859 #endif
860   return db->nChange;
861 }
862 
863 /*
864 ** Return the number of changes since the database handle was opened.
865 */
866 int sqlite3_total_changes(sqlite3 *db){
867 #ifdef SQLITE_ENABLE_API_ARMOR
868   if( !sqlite3SafetyCheckOk(db) ){
869     (void)SQLITE_MISUSE_BKPT;
870     return 0;
871   }
872 #endif
873   return db->nTotalChange;
874 }
875 
876 /*
877 ** Close all open savepoints. This function only manipulates fields of the
878 ** database handle object, it does not close any savepoints that may be open
879 ** at the b-tree/pager level.
880 */
881 void sqlite3CloseSavepoints(sqlite3 *db){
882   while( db->pSavepoint ){
883     Savepoint *pTmp = db->pSavepoint;
884     db->pSavepoint = pTmp->pNext;
885     sqlite3DbFree(db, pTmp);
886   }
887   db->nSavepoint = 0;
888   db->nStatement = 0;
889   db->isTransactionSavepoint = 0;
890 }
891 
892 /*
893 ** Invoke the destructor function associated with FuncDef p, if any. Except,
894 ** if this is not the last copy of the function, do not invoke it. Multiple
895 ** copies of a single function are created when create_function() is called
896 ** with SQLITE_ANY as the encoding.
897 */
898 static void functionDestroy(sqlite3 *db, FuncDef *p){
899   FuncDestructor *pDestructor = p->pDestructor;
900   if( pDestructor ){
901     pDestructor->nRef--;
902     if( pDestructor->nRef==0 ){
903       pDestructor->xDestroy(pDestructor->pUserData);
904       sqlite3DbFree(db, pDestructor);
905     }
906   }
907 }
908 
909 /*
910 ** Disconnect all sqlite3_vtab objects that belong to database connection
911 ** db. This is called when db is being closed.
912 */
913 static void disconnectAllVtab(sqlite3 *db){
914 #ifndef SQLITE_OMIT_VIRTUALTABLE
915   int i;
916   sqlite3BtreeEnterAll(db);
917   for(i=0; i<db->nDb; i++){
918     Schema *pSchema = db->aDb[i].pSchema;
919     if( db->aDb[i].pSchema ){
920       HashElem *p;
921       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
922         Table *pTab = (Table *)sqliteHashData(p);
923         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
924       }
925     }
926   }
927   sqlite3VtabUnlockList(db);
928   sqlite3BtreeLeaveAll(db);
929 #else
930   UNUSED_PARAMETER(db);
931 #endif
932 }
933 
934 /*
935 ** Return TRUE if database connection db has unfinalized prepared
936 ** statements or unfinished sqlite3_backup objects.
937 */
938 static int connectionIsBusy(sqlite3 *db){
939   int j;
940   assert( sqlite3_mutex_held(db->mutex) );
941   if( db->pVdbe ) return 1;
942   for(j=0; j<db->nDb; j++){
943     Btree *pBt = db->aDb[j].pBt;
944     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
945   }
946   return 0;
947 }
948 
949 /*
950 ** Close an existing SQLite database
951 */
952 static int sqlite3Close(sqlite3 *db, int forceZombie){
953   if( !db ){
954     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
955     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
956     return SQLITE_OK;
957   }
958   if( !sqlite3SafetyCheckSickOrOk(db) ){
959     return SQLITE_MISUSE_BKPT;
960   }
961   sqlite3_mutex_enter(db->mutex);
962 
963   /* Force xDisconnect calls on all virtual tables */
964   disconnectAllVtab(db);
965 
966   /* If a transaction is open, the disconnectAllVtab() call above
967   ** will not have called the xDisconnect() method on any virtual
968   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
969   ** call will do so. We need to do this before the check for active
970   ** SQL statements below, as the v-table implementation may be storing
971   ** some prepared statements internally.
972   */
973   sqlite3VtabRollback(db);
974 
975   /* Legacy behavior (sqlite3_close() behavior) is to return
976   ** SQLITE_BUSY if the connection can not be closed immediately.
977   */
978   if( !forceZombie && connectionIsBusy(db) ){
979     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
980        "statements or unfinished backups");
981     sqlite3_mutex_leave(db->mutex);
982     return SQLITE_BUSY;
983   }
984 
985 #ifdef SQLITE_ENABLE_SQLLOG
986   if( sqlite3GlobalConfig.xSqllog ){
987     /* Closing the handle. Fourth parameter is passed the value 2. */
988     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
989   }
990 #endif
991 
992   /* Convert the connection into a zombie and then close it.
993   */
994   db->magic = SQLITE_MAGIC_ZOMBIE;
995   sqlite3LeaveMutexAndCloseZombie(db);
996   return SQLITE_OK;
997 }
998 
999 /*
1000 ** Two variations on the public interface for closing a database
1001 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1002 ** leaves the connection option if there are unfinalized prepared
1003 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1004 ** version forces the connection to become a zombie if there are
1005 ** unclosed resources, and arranges for deallocation when the last
1006 ** prepare statement or sqlite3_backup closes.
1007 */
1008 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1009 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1010 
1011 
1012 /*
1013 ** Close the mutex on database connection db.
1014 **
1015 ** Furthermore, if database connection db is a zombie (meaning that there
1016 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1017 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1018 ** finished, then free all resources.
1019 */
1020 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1021   HashElem *i;                    /* Hash table iterator */
1022   int j;
1023 
1024   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1025   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1026   ** then just leave the mutex and return.
1027   */
1028   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1029     sqlite3_mutex_leave(db->mutex);
1030     return;
1031   }
1032 
1033   /* If we reach this point, it means that the database connection has
1034   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1035   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1036   ** go ahead and free all resources.
1037   */
1038 
1039   /* If a transaction is open, roll it back. This also ensures that if
1040   ** any database schemas have been modified by an uncommitted transaction
1041   ** they are reset. And that the required b-tree mutex is held to make
1042   ** the pager rollback and schema reset an atomic operation. */
1043   sqlite3RollbackAll(db, SQLITE_OK);
1044 
1045   /* Free any outstanding Savepoint structures. */
1046   sqlite3CloseSavepoints(db);
1047 
1048   /* Close all database connections */
1049   for(j=0; j<db->nDb; j++){
1050     struct Db *pDb = &db->aDb[j];
1051     if( pDb->pBt ){
1052       sqlite3BtreeClose(pDb->pBt);
1053       pDb->pBt = 0;
1054       if( j!=1 ){
1055         pDb->pSchema = 0;
1056       }
1057     }
1058   }
1059   /* Clear the TEMP schema separately and last */
1060   if( db->aDb[1].pSchema ){
1061     sqlite3SchemaClear(db->aDb[1].pSchema);
1062   }
1063   sqlite3VtabUnlockList(db);
1064 
1065   /* Free up the array of auxiliary databases */
1066   sqlite3CollapseDatabaseArray(db);
1067   assert( db->nDb<=2 );
1068   assert( db->aDb==db->aDbStatic );
1069 
1070   /* Tell the code in notify.c that the connection no longer holds any
1071   ** locks and does not require any further unlock-notify callbacks.
1072   */
1073   sqlite3ConnectionClosed(db);
1074 
1075   for(j=0; j<ArraySize(db->aFunc.a); j++){
1076     FuncDef *pNext, *pHash, *p;
1077     for(p=db->aFunc.a[j]; p; p=pHash){
1078       pHash = p->pHash;
1079       while( p ){
1080         functionDestroy(db, p);
1081         pNext = p->pNext;
1082         sqlite3DbFree(db, p);
1083         p = pNext;
1084       }
1085     }
1086   }
1087   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1088     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1089     /* Invoke any destructors registered for collation sequence user data. */
1090     for(j=0; j<3; j++){
1091       if( pColl[j].xDel ){
1092         pColl[j].xDel(pColl[j].pUser);
1093       }
1094     }
1095     sqlite3DbFree(db, pColl);
1096   }
1097   sqlite3HashClear(&db->aCollSeq);
1098 #ifndef SQLITE_OMIT_VIRTUALTABLE
1099   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1100     Module *pMod = (Module *)sqliteHashData(i);
1101     if( pMod->xDestroy ){
1102       pMod->xDestroy(pMod->pAux);
1103     }
1104     sqlite3DbFree(db, pMod);
1105   }
1106   sqlite3HashClear(&db->aModule);
1107 #endif
1108 
1109   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1110   sqlite3ValueFree(db->pErr);
1111   sqlite3CloseExtensions(db);
1112 #if SQLITE_USER_AUTHENTICATION
1113   sqlite3_free(db->auth.zAuthUser);
1114   sqlite3_free(db->auth.zAuthPW);
1115 #endif
1116 
1117   db->magic = SQLITE_MAGIC_ERROR;
1118 
1119   /* The temp-database schema is allocated differently from the other schema
1120   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1121   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1122   ** the same sqliteMalloc() as the one that allocates the database
1123   ** structure?
1124   */
1125   sqlite3DbFree(db, db->aDb[1].pSchema);
1126   sqlite3_mutex_leave(db->mutex);
1127   db->magic = SQLITE_MAGIC_CLOSED;
1128   sqlite3_mutex_free(db->mutex);
1129   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1130   if( db->lookaside.bMalloced ){
1131     sqlite3_free(db->lookaside.pStart);
1132   }
1133   sqlite3_free(db);
1134 }
1135 
1136 /*
1137 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1138 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1139 ** breaker") and made to return tripCode if there are any further
1140 ** attempts to use that cursor.  Read cursors remain open and valid
1141 ** but are "saved" in case the table pages are moved around.
1142 */
1143 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1144   int i;
1145   int inTrans = 0;
1146   int schemaChange;
1147   assert( sqlite3_mutex_held(db->mutex) );
1148   sqlite3BeginBenignMalloc();
1149 
1150   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1151   ** This is important in case the transaction being rolled back has
1152   ** modified the database schema. If the b-tree mutexes are not taken
1153   ** here, then another shared-cache connection might sneak in between
1154   ** the database rollback and schema reset, which can cause false
1155   ** corruption reports in some cases.  */
1156   sqlite3BtreeEnterAll(db);
1157   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1158 
1159   for(i=0; i<db->nDb; i++){
1160     Btree *p = db->aDb[i].pBt;
1161     if( p ){
1162       if( sqlite3BtreeIsInTrans(p) ){
1163         inTrans = 1;
1164       }
1165       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1166     }
1167   }
1168   sqlite3VtabRollback(db);
1169   sqlite3EndBenignMalloc();
1170 
1171   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1172     sqlite3ExpirePreparedStatements(db);
1173     sqlite3ResetAllSchemasOfConnection(db);
1174   }
1175   sqlite3BtreeLeaveAll(db);
1176 
1177   /* Any deferred constraint violations have now been resolved. */
1178   db->nDeferredCons = 0;
1179   db->nDeferredImmCons = 0;
1180   db->flags &= ~SQLITE_DeferFKs;
1181 
1182   /* If one has been configured, invoke the rollback-hook callback */
1183   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1184     db->xRollbackCallback(db->pRollbackArg);
1185   }
1186 }
1187 
1188 /*
1189 ** Return a static string containing the name corresponding to the error code
1190 ** specified in the argument.
1191 */
1192 #if (defined(SQLITE_DEBUG) && SQLITE_OS_WIN) || defined(SQLITE_TEST)
1193 const char *sqlite3ErrName(int rc){
1194   const char *zName = 0;
1195   int i, origRc = rc;
1196   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1197     switch( rc ){
1198       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1199       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1200       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1201       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1202       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1203       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1204       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1205       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1206       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1207       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1208       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1209       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1210       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1211       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1212       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1213       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1214       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1215       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1216       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1217       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1218       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1219       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1220       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1221       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1222       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1223       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1224       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1225       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1226       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1227       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1228       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1229       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1230                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1231       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1232       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1233       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1234       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1235       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1236       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1237       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1238       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1239       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1240       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1241       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1242       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1243       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1244       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1245       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1246       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1247       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1248       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1249       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1250       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1251       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1252       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1253       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1254       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1255       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1256       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1257       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1258       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1259       case SQLITE_CONSTRAINT_FOREIGNKEY:
1260                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1261       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1262       case SQLITE_CONSTRAINT_PRIMARYKEY:
1263                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1264       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1265       case SQLITE_CONSTRAINT_COMMITHOOK:
1266                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1267       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1268       case SQLITE_CONSTRAINT_FUNCTION:
1269                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1270       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1271       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1272       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1273       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1274       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1275       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1276       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1277       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1278       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1279       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1280       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1281       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1282                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1283       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1284       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1285       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1286     }
1287   }
1288   if( zName==0 ){
1289     static char zBuf[50];
1290     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1291     zName = zBuf;
1292   }
1293   return zName;
1294 }
1295 #endif
1296 
1297 /*
1298 ** Return a static string that describes the kind of error specified in the
1299 ** argument.
1300 */
1301 const char *sqlite3ErrStr(int rc){
1302   static const char* const aMsg[] = {
1303     /* SQLITE_OK          */ "not an error",
1304     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1305     /* SQLITE_INTERNAL    */ 0,
1306     /* SQLITE_PERM        */ "access permission denied",
1307     /* SQLITE_ABORT       */ "callback requested query abort",
1308     /* SQLITE_BUSY        */ "database is locked",
1309     /* SQLITE_LOCKED      */ "database table is locked",
1310     /* SQLITE_NOMEM       */ "out of memory",
1311     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1312     /* SQLITE_INTERRUPT   */ "interrupted",
1313     /* SQLITE_IOERR       */ "disk I/O error",
1314     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1315     /* SQLITE_NOTFOUND    */ "unknown operation",
1316     /* SQLITE_FULL        */ "database or disk is full",
1317     /* SQLITE_CANTOPEN    */ "unable to open database file",
1318     /* SQLITE_PROTOCOL    */ "locking protocol",
1319     /* SQLITE_EMPTY       */ "table contains no data",
1320     /* SQLITE_SCHEMA      */ "database schema has changed",
1321     /* SQLITE_TOOBIG      */ "string or blob too big",
1322     /* SQLITE_CONSTRAINT  */ "constraint failed",
1323     /* SQLITE_MISMATCH    */ "datatype mismatch",
1324     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1325     /* SQLITE_NOLFS       */ "large file support is disabled",
1326     /* SQLITE_AUTH        */ "authorization denied",
1327     /* SQLITE_FORMAT      */ "auxiliary database format error",
1328     /* SQLITE_RANGE       */ "bind or column index out of range",
1329     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1330   };
1331   const char *zErr = "unknown error";
1332   switch( rc ){
1333     case SQLITE_ABORT_ROLLBACK: {
1334       zErr = "abort due to ROLLBACK";
1335       break;
1336     }
1337     default: {
1338       rc &= 0xff;
1339       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1340         zErr = aMsg[rc];
1341       }
1342       break;
1343     }
1344   }
1345   return zErr;
1346 }
1347 
1348 /*
1349 ** This routine implements a busy callback that sleeps and tries
1350 ** again until a timeout value is reached.  The timeout value is
1351 ** an integer number of milliseconds passed in as the first
1352 ** argument.
1353 */
1354 static int sqliteDefaultBusyCallback(
1355  void *ptr,               /* Database connection */
1356  int count                /* Number of times table has been busy */
1357 ){
1358 #if SQLITE_OS_WIN || HAVE_USLEEP
1359   static const u8 delays[] =
1360      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1361   static const u8 totals[] =
1362      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1363 # define NDELAY ArraySize(delays)
1364   sqlite3 *db = (sqlite3 *)ptr;
1365   int timeout = db->busyTimeout;
1366   int delay, prior;
1367 
1368   assert( count>=0 );
1369   if( count < NDELAY ){
1370     delay = delays[count];
1371     prior = totals[count];
1372   }else{
1373     delay = delays[NDELAY-1];
1374     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1375   }
1376   if( prior + delay > timeout ){
1377     delay = timeout - prior;
1378     if( delay<=0 ) return 0;
1379   }
1380   sqlite3OsSleep(db->pVfs, delay*1000);
1381   return 1;
1382 #else
1383   sqlite3 *db = (sqlite3 *)ptr;
1384   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1385   if( (count+1)*1000 > timeout ){
1386     return 0;
1387   }
1388   sqlite3OsSleep(db->pVfs, 1000000);
1389   return 1;
1390 #endif
1391 }
1392 
1393 /*
1394 ** Invoke the given busy handler.
1395 **
1396 ** This routine is called when an operation failed with a lock.
1397 ** If this routine returns non-zero, the lock is retried.  If it
1398 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1399 */
1400 int sqlite3InvokeBusyHandler(BusyHandler *p){
1401   int rc;
1402   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1403   rc = p->xFunc(p->pArg, p->nBusy);
1404   if( rc==0 ){
1405     p->nBusy = -1;
1406   }else{
1407     p->nBusy++;
1408   }
1409   return rc;
1410 }
1411 
1412 /*
1413 ** This routine sets the busy callback for an Sqlite database to the
1414 ** given callback function with the given argument.
1415 */
1416 int sqlite3_busy_handler(
1417   sqlite3 *db,
1418   int (*xBusy)(void*,int),
1419   void *pArg
1420 ){
1421 #ifdef SQLITE_ENABLE_API_ARMOR
1422   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1423 #endif
1424   sqlite3_mutex_enter(db->mutex);
1425   db->busyHandler.xFunc = xBusy;
1426   db->busyHandler.pArg = pArg;
1427   db->busyHandler.nBusy = 0;
1428   db->busyTimeout = 0;
1429   sqlite3_mutex_leave(db->mutex);
1430   return SQLITE_OK;
1431 }
1432 
1433 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1434 /*
1435 ** This routine sets the progress callback for an Sqlite database to the
1436 ** given callback function with the given argument. The progress callback will
1437 ** be invoked every nOps opcodes.
1438 */
1439 void sqlite3_progress_handler(
1440   sqlite3 *db,
1441   int nOps,
1442   int (*xProgress)(void*),
1443   void *pArg
1444 ){
1445 #ifdef SQLITE_ENABLE_API_ARMOR
1446   if( !sqlite3SafetyCheckOk(db) ){
1447     (void)SQLITE_MISUSE_BKPT;
1448     return;
1449   }
1450 #endif
1451   sqlite3_mutex_enter(db->mutex);
1452   if( nOps>0 ){
1453     db->xProgress = xProgress;
1454     db->nProgressOps = (unsigned)nOps;
1455     db->pProgressArg = pArg;
1456   }else{
1457     db->xProgress = 0;
1458     db->nProgressOps = 0;
1459     db->pProgressArg = 0;
1460   }
1461   sqlite3_mutex_leave(db->mutex);
1462 }
1463 #endif
1464 
1465 
1466 /*
1467 ** This routine installs a default busy handler that waits for the
1468 ** specified number of milliseconds before returning 0.
1469 */
1470 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1471 #ifdef SQLITE_ENABLE_API_ARMOR
1472   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1473 #endif
1474   if( ms>0 ){
1475     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1476     db->busyTimeout = ms;
1477   }else{
1478     sqlite3_busy_handler(db, 0, 0);
1479   }
1480   return SQLITE_OK;
1481 }
1482 
1483 /*
1484 ** Cause any pending operation to stop at its earliest opportunity.
1485 */
1486 void sqlite3_interrupt(sqlite3 *db){
1487 #ifdef SQLITE_ENABLE_API_ARMOR
1488   if( !sqlite3SafetyCheckOk(db) ){
1489     (void)SQLITE_MISUSE_BKPT;
1490     return;
1491   }
1492 #endif
1493   db->u1.isInterrupted = 1;
1494 }
1495 
1496 
1497 /*
1498 ** This function is exactly the same as sqlite3_create_function(), except
1499 ** that it is designed to be called by internal code. The difference is
1500 ** that if a malloc() fails in sqlite3_create_function(), an error code
1501 ** is returned and the mallocFailed flag cleared.
1502 */
1503 int sqlite3CreateFunc(
1504   sqlite3 *db,
1505   const char *zFunctionName,
1506   int nArg,
1507   int enc,
1508   void *pUserData,
1509   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1510   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1511   void (*xFinal)(sqlite3_context*),
1512   FuncDestructor *pDestructor
1513 ){
1514   FuncDef *p;
1515   int nName;
1516   int extraFlags;
1517 
1518   assert( sqlite3_mutex_held(db->mutex) );
1519   if( zFunctionName==0 ||
1520       (xFunc && (xFinal || xStep)) ||
1521       (!xFunc && (xFinal && !xStep)) ||
1522       (!xFunc && (!xFinal && xStep)) ||
1523       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1524       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1525     return SQLITE_MISUSE_BKPT;
1526   }
1527 
1528   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1529   extraFlags = enc &  SQLITE_DETERMINISTIC;
1530   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1531 
1532 #ifndef SQLITE_OMIT_UTF16
1533   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1534   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1535   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1536   **
1537   ** If SQLITE_ANY is specified, add three versions of the function
1538   ** to the hash table.
1539   */
1540   if( enc==SQLITE_UTF16 ){
1541     enc = SQLITE_UTF16NATIVE;
1542   }else if( enc==SQLITE_ANY ){
1543     int rc;
1544     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1545          pUserData, xFunc, xStep, xFinal, pDestructor);
1546     if( rc==SQLITE_OK ){
1547       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1548           pUserData, xFunc, xStep, xFinal, pDestructor);
1549     }
1550     if( rc!=SQLITE_OK ){
1551       return rc;
1552     }
1553     enc = SQLITE_UTF16BE;
1554   }
1555 #else
1556   enc = SQLITE_UTF8;
1557 #endif
1558 
1559   /* Check if an existing function is being overridden or deleted. If so,
1560   ** and there are active VMs, then return SQLITE_BUSY. If a function
1561   ** is being overridden/deleted but there are no active VMs, allow the
1562   ** operation to continue but invalidate all precompiled statements.
1563   */
1564   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 0);
1565   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1566     if( db->nVdbeActive ){
1567       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1568         "unable to delete/modify user-function due to active statements");
1569       assert( !db->mallocFailed );
1570       return SQLITE_BUSY;
1571     }else{
1572       sqlite3ExpirePreparedStatements(db);
1573     }
1574   }
1575 
1576   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 1);
1577   assert(p || db->mallocFailed);
1578   if( !p ){
1579     return SQLITE_NOMEM;
1580   }
1581 
1582   /* If an older version of the function with a configured destructor is
1583   ** being replaced invoke the destructor function here. */
1584   functionDestroy(db, p);
1585 
1586   if( pDestructor ){
1587     pDestructor->nRef++;
1588   }
1589   p->pDestructor = pDestructor;
1590   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1591   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1592   p->xFunc = xFunc;
1593   p->xStep = xStep;
1594   p->xFinalize = xFinal;
1595   p->pUserData = pUserData;
1596   p->nArg = (u16)nArg;
1597   return SQLITE_OK;
1598 }
1599 
1600 /*
1601 ** Create new user functions.
1602 */
1603 int sqlite3_create_function(
1604   sqlite3 *db,
1605   const char *zFunc,
1606   int nArg,
1607   int enc,
1608   void *p,
1609   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1610   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1611   void (*xFinal)(sqlite3_context*)
1612 ){
1613   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xFunc, xStep,
1614                                     xFinal, 0);
1615 }
1616 
1617 int sqlite3_create_function_v2(
1618   sqlite3 *db,
1619   const char *zFunc,
1620   int nArg,
1621   int enc,
1622   void *p,
1623   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1624   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1625   void (*xFinal)(sqlite3_context*),
1626   void (*xDestroy)(void *)
1627 ){
1628   int rc = SQLITE_ERROR;
1629   FuncDestructor *pArg = 0;
1630 
1631 #ifdef SQLITE_ENABLE_API_ARMOR
1632   if( !sqlite3SafetyCheckOk(db) ){
1633     return SQLITE_MISUSE_BKPT;
1634   }
1635 #endif
1636   sqlite3_mutex_enter(db->mutex);
1637   if( xDestroy ){
1638     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1639     if( !pArg ){
1640       xDestroy(p);
1641       goto out;
1642     }
1643     pArg->xDestroy = xDestroy;
1644     pArg->pUserData = p;
1645   }
1646   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, pArg);
1647   if( pArg && pArg->nRef==0 ){
1648     assert( rc!=SQLITE_OK );
1649     xDestroy(p);
1650     sqlite3DbFree(db, pArg);
1651   }
1652 
1653  out:
1654   rc = sqlite3ApiExit(db, rc);
1655   sqlite3_mutex_leave(db->mutex);
1656   return rc;
1657 }
1658 
1659 #ifndef SQLITE_OMIT_UTF16
1660 int sqlite3_create_function16(
1661   sqlite3 *db,
1662   const void *zFunctionName,
1663   int nArg,
1664   int eTextRep,
1665   void *p,
1666   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
1667   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1668   void (*xFinal)(sqlite3_context*)
1669 ){
1670   int rc;
1671   char *zFunc8;
1672 
1673 #ifdef SQLITE_ENABLE_API_ARMOR
1674   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1675 #endif
1676   sqlite3_mutex_enter(db->mutex);
1677   assert( !db->mallocFailed );
1678   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1679   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
1680   sqlite3DbFree(db, zFunc8);
1681   rc = sqlite3ApiExit(db, rc);
1682   sqlite3_mutex_leave(db->mutex);
1683   return rc;
1684 }
1685 #endif
1686 
1687 
1688 /*
1689 ** Declare that a function has been overloaded by a virtual table.
1690 **
1691 ** If the function already exists as a regular global function, then
1692 ** this routine is a no-op.  If the function does not exist, then create
1693 ** a new one that always throws a run-time error.
1694 **
1695 ** When virtual tables intend to provide an overloaded function, they
1696 ** should call this routine to make sure the global function exists.
1697 ** A global function must exist in order for name resolution to work
1698 ** properly.
1699 */
1700 int sqlite3_overload_function(
1701   sqlite3 *db,
1702   const char *zName,
1703   int nArg
1704 ){
1705   int nName = sqlite3Strlen30(zName);
1706   int rc = SQLITE_OK;
1707 
1708 #ifdef SQLITE_ENABLE_API_ARMOR
1709   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1710     return SQLITE_MISUSE_BKPT;
1711   }
1712 #endif
1713   sqlite3_mutex_enter(db->mutex);
1714   if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
1715     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1716                            0, sqlite3InvalidFunction, 0, 0, 0);
1717   }
1718   rc = sqlite3ApiExit(db, rc);
1719   sqlite3_mutex_leave(db->mutex);
1720   return rc;
1721 }
1722 
1723 #ifndef SQLITE_OMIT_TRACE
1724 /*
1725 ** Register a trace function.  The pArg from the previously registered trace
1726 ** is returned.
1727 **
1728 ** A NULL trace function means that no tracing is executes.  A non-NULL
1729 ** trace is a pointer to a function that is invoked at the start of each
1730 ** SQL statement.
1731 */
1732 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1733   void *pOld;
1734 
1735 #ifdef SQLITE_ENABLE_API_ARMOR
1736   if( !sqlite3SafetyCheckOk(db) ){
1737     (void)SQLITE_MISUSE_BKPT;
1738     return 0;
1739   }
1740 #endif
1741   sqlite3_mutex_enter(db->mutex);
1742   pOld = db->pTraceArg;
1743   db->xTrace = xTrace;
1744   db->pTraceArg = pArg;
1745   sqlite3_mutex_leave(db->mutex);
1746   return pOld;
1747 }
1748 /*
1749 ** Register a profile function.  The pArg from the previously registered
1750 ** profile function is returned.
1751 **
1752 ** A NULL profile function means that no profiling is executes.  A non-NULL
1753 ** profile is a pointer to a function that is invoked at the conclusion of
1754 ** each SQL statement that is run.
1755 */
1756 void *sqlite3_profile(
1757   sqlite3 *db,
1758   void (*xProfile)(void*,const char*,sqlite_uint64),
1759   void *pArg
1760 ){
1761   void *pOld;
1762 
1763 #ifdef SQLITE_ENABLE_API_ARMOR
1764   if( !sqlite3SafetyCheckOk(db) ){
1765     (void)SQLITE_MISUSE_BKPT;
1766     return 0;
1767   }
1768 #endif
1769   sqlite3_mutex_enter(db->mutex);
1770   pOld = db->pProfileArg;
1771   db->xProfile = xProfile;
1772   db->pProfileArg = pArg;
1773   sqlite3_mutex_leave(db->mutex);
1774   return pOld;
1775 }
1776 #endif /* SQLITE_OMIT_TRACE */
1777 
1778 /*
1779 ** Register a function to be invoked when a transaction commits.
1780 ** If the invoked function returns non-zero, then the commit becomes a
1781 ** rollback.
1782 */
1783 void *sqlite3_commit_hook(
1784   sqlite3 *db,              /* Attach the hook to this database */
1785   int (*xCallback)(void*),  /* Function to invoke on each commit */
1786   void *pArg                /* Argument to the function */
1787 ){
1788   void *pOld;
1789 
1790 #ifdef SQLITE_ENABLE_API_ARMOR
1791   if( !sqlite3SafetyCheckOk(db) ){
1792     (void)SQLITE_MISUSE_BKPT;
1793     return 0;
1794   }
1795 #endif
1796   sqlite3_mutex_enter(db->mutex);
1797   pOld = db->pCommitArg;
1798   db->xCommitCallback = xCallback;
1799   db->pCommitArg = pArg;
1800   sqlite3_mutex_leave(db->mutex);
1801   return pOld;
1802 }
1803 
1804 /*
1805 ** Register a callback to be invoked each time a row is updated,
1806 ** inserted or deleted using this database connection.
1807 */
1808 void *sqlite3_update_hook(
1809   sqlite3 *db,              /* Attach the hook to this database */
1810   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1811   void *pArg                /* Argument to the function */
1812 ){
1813   void *pRet;
1814 
1815 #ifdef SQLITE_ENABLE_API_ARMOR
1816   if( !sqlite3SafetyCheckOk(db) ){
1817     (void)SQLITE_MISUSE_BKPT;
1818     return 0;
1819   }
1820 #endif
1821   sqlite3_mutex_enter(db->mutex);
1822   pRet = db->pUpdateArg;
1823   db->xUpdateCallback = xCallback;
1824   db->pUpdateArg = pArg;
1825   sqlite3_mutex_leave(db->mutex);
1826   return pRet;
1827 }
1828 
1829 /*
1830 ** Register a callback to be invoked each time a transaction is rolled
1831 ** back by this database connection.
1832 */
1833 void *sqlite3_rollback_hook(
1834   sqlite3 *db,              /* Attach the hook to this database */
1835   void (*xCallback)(void*), /* Callback function */
1836   void *pArg                /* Argument to the function */
1837 ){
1838   void *pRet;
1839 
1840 #ifdef SQLITE_ENABLE_API_ARMOR
1841   if( !sqlite3SafetyCheckOk(db) ){
1842     (void)SQLITE_MISUSE_BKPT;
1843     return 0;
1844   }
1845 #endif
1846   sqlite3_mutex_enter(db->mutex);
1847   pRet = db->pRollbackArg;
1848   db->xRollbackCallback = xCallback;
1849   db->pRollbackArg = pArg;
1850   sqlite3_mutex_leave(db->mutex);
1851   return pRet;
1852 }
1853 
1854 #ifndef SQLITE_OMIT_WAL
1855 /*
1856 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1857 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1858 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1859 ** wal_autocheckpoint()).
1860 */
1861 int sqlite3WalDefaultHook(
1862   void *pClientData,     /* Argument */
1863   sqlite3 *db,           /* Connection */
1864   const char *zDb,       /* Database */
1865   int nFrame             /* Size of WAL */
1866 ){
1867   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1868     sqlite3BeginBenignMalloc();
1869     sqlite3_wal_checkpoint(db, zDb);
1870     sqlite3EndBenignMalloc();
1871   }
1872   return SQLITE_OK;
1873 }
1874 #endif /* SQLITE_OMIT_WAL */
1875 
1876 /*
1877 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1878 ** a database after committing a transaction if there are nFrame or
1879 ** more frames in the log file. Passing zero or a negative value as the
1880 ** nFrame parameter disables automatic checkpoints entirely.
1881 **
1882 ** The callback registered by this function replaces any existing callback
1883 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1884 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1885 ** configured by this function.
1886 */
1887 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1888 #ifdef SQLITE_OMIT_WAL
1889   UNUSED_PARAMETER(db);
1890   UNUSED_PARAMETER(nFrame);
1891 #else
1892 #ifdef SQLITE_ENABLE_API_ARMOR
1893   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1894 #endif
1895   if( nFrame>0 ){
1896     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1897   }else{
1898     sqlite3_wal_hook(db, 0, 0);
1899   }
1900 #endif
1901   return SQLITE_OK;
1902 }
1903 
1904 /*
1905 ** Register a callback to be invoked each time a transaction is written
1906 ** into the write-ahead-log by this database connection.
1907 */
1908 void *sqlite3_wal_hook(
1909   sqlite3 *db,                    /* Attach the hook to this db handle */
1910   int(*xCallback)(void *, sqlite3*, const char*, int),
1911   void *pArg                      /* First argument passed to xCallback() */
1912 ){
1913 #ifndef SQLITE_OMIT_WAL
1914   void *pRet;
1915 #ifdef SQLITE_ENABLE_API_ARMOR
1916   if( !sqlite3SafetyCheckOk(db) ){
1917     (void)SQLITE_MISUSE_BKPT;
1918     return 0;
1919   }
1920 #endif
1921   sqlite3_mutex_enter(db->mutex);
1922   pRet = db->pWalArg;
1923   db->xWalCallback = xCallback;
1924   db->pWalArg = pArg;
1925   sqlite3_mutex_leave(db->mutex);
1926   return pRet;
1927 #else
1928   return 0;
1929 #endif
1930 }
1931 
1932 /*
1933 ** Checkpoint database zDb.
1934 */
1935 int sqlite3_wal_checkpoint_v2(
1936   sqlite3 *db,                    /* Database handle */
1937   const char *zDb,                /* Name of attached database (or NULL) */
1938   int eMode,                      /* SQLITE_CHECKPOINT_* value */
1939   int *pnLog,                     /* OUT: Size of WAL log in frames */
1940   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
1941 ){
1942 #ifdef SQLITE_OMIT_WAL
1943   return SQLITE_OK;
1944 #else
1945   int rc;                         /* Return code */
1946   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
1947 
1948 #ifdef SQLITE_ENABLE_API_ARMOR
1949   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1950 #endif
1951 
1952   /* Initialize the output variables to -1 in case an error occurs. */
1953   if( pnLog ) *pnLog = -1;
1954   if( pnCkpt ) *pnCkpt = -1;
1955 
1956   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
1957   assert( SQLITE_CHECKPOINT_FULL==1 );
1958   assert( SQLITE_CHECKPOINT_RESTART==2 );
1959   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
1960   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
1961     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
1962     ** mode: */
1963     return SQLITE_MISUSE;
1964   }
1965 
1966   sqlite3_mutex_enter(db->mutex);
1967   if( zDb && zDb[0] ){
1968     iDb = sqlite3FindDbName(db, zDb);
1969   }
1970   if( iDb<0 ){
1971     rc = SQLITE_ERROR;
1972     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
1973   }else{
1974     db->busyHandler.nBusy = 0;
1975     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
1976     sqlite3Error(db, rc);
1977   }
1978   rc = sqlite3ApiExit(db, rc);
1979   sqlite3_mutex_leave(db->mutex);
1980   return rc;
1981 #endif
1982 }
1983 
1984 
1985 /*
1986 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
1987 ** to contains a zero-length string, all attached databases are
1988 ** checkpointed.
1989 */
1990 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
1991   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
1992   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
1993   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
1994 }
1995 
1996 #ifndef SQLITE_OMIT_WAL
1997 /*
1998 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
1999 ** not currently open in WAL mode.
2000 **
2001 ** If a transaction is open on the database being checkpointed, this
2002 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2003 ** an error occurs while running the checkpoint, an SQLite error code is
2004 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2005 **
2006 ** The mutex on database handle db should be held by the caller. The mutex
2007 ** associated with the specific b-tree being checkpointed is taken by
2008 ** this function while the checkpoint is running.
2009 **
2010 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2011 ** checkpointed. If an error is encountered it is returned immediately -
2012 ** no attempt is made to checkpoint any remaining databases.
2013 **
2014 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2015 */
2016 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2017   int rc = SQLITE_OK;             /* Return code */
2018   int i;                          /* Used to iterate through attached dbs */
2019   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2020 
2021   assert( sqlite3_mutex_held(db->mutex) );
2022   assert( !pnLog || *pnLog==-1 );
2023   assert( !pnCkpt || *pnCkpt==-1 );
2024 
2025   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2026     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2027       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2028       pnLog = 0;
2029       pnCkpt = 0;
2030       if( rc==SQLITE_BUSY ){
2031         bBusy = 1;
2032         rc = SQLITE_OK;
2033       }
2034     }
2035   }
2036 
2037   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2038 }
2039 #endif /* SQLITE_OMIT_WAL */
2040 
2041 /*
2042 ** This function returns true if main-memory should be used instead of
2043 ** a temporary file for transient pager files and statement journals.
2044 ** The value returned depends on the value of db->temp_store (runtime
2045 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2046 ** following table describes the relationship between these two values
2047 ** and this functions return value.
2048 **
2049 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2050 **   -----------------     --------------     ------------------------------
2051 **   0                     any                file      (return 0)
2052 **   1                     1                  file      (return 0)
2053 **   1                     2                  memory    (return 1)
2054 **   1                     0                  file      (return 0)
2055 **   2                     1                  file      (return 0)
2056 **   2                     2                  memory    (return 1)
2057 **   2                     0                  memory    (return 1)
2058 **   3                     any                memory    (return 1)
2059 */
2060 int sqlite3TempInMemory(const sqlite3 *db){
2061 #if SQLITE_TEMP_STORE==1
2062   return ( db->temp_store==2 );
2063 #endif
2064 #if SQLITE_TEMP_STORE==2
2065   return ( db->temp_store!=1 );
2066 #endif
2067 #if SQLITE_TEMP_STORE==3
2068   return 1;
2069 #endif
2070 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2071   return 0;
2072 #endif
2073 }
2074 
2075 /*
2076 ** Return UTF-8 encoded English language explanation of the most recent
2077 ** error.
2078 */
2079 const char *sqlite3_errmsg(sqlite3 *db){
2080   const char *z;
2081   if( !db ){
2082     return sqlite3ErrStr(SQLITE_NOMEM);
2083   }
2084   if( !sqlite3SafetyCheckSickOrOk(db) ){
2085     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2086   }
2087   sqlite3_mutex_enter(db->mutex);
2088   if( db->mallocFailed ){
2089     z = sqlite3ErrStr(SQLITE_NOMEM);
2090   }else{
2091     testcase( db->pErr==0 );
2092     z = (char*)sqlite3_value_text(db->pErr);
2093     assert( !db->mallocFailed );
2094     if( z==0 ){
2095       z = sqlite3ErrStr(db->errCode);
2096     }
2097   }
2098   sqlite3_mutex_leave(db->mutex);
2099   return z;
2100 }
2101 
2102 #ifndef SQLITE_OMIT_UTF16
2103 /*
2104 ** Return UTF-16 encoded English language explanation of the most recent
2105 ** error.
2106 */
2107 const void *sqlite3_errmsg16(sqlite3 *db){
2108   static const u16 outOfMem[] = {
2109     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2110   };
2111   static const u16 misuse[] = {
2112     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2113     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2114     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2115     'o', 'u', 't', ' ',
2116     'o', 'f', ' ',
2117     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2118   };
2119 
2120   const void *z;
2121   if( !db ){
2122     return (void *)outOfMem;
2123   }
2124   if( !sqlite3SafetyCheckSickOrOk(db) ){
2125     return (void *)misuse;
2126   }
2127   sqlite3_mutex_enter(db->mutex);
2128   if( db->mallocFailed ){
2129     z = (void *)outOfMem;
2130   }else{
2131     z = sqlite3_value_text16(db->pErr);
2132     if( z==0 ){
2133       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2134       z = sqlite3_value_text16(db->pErr);
2135     }
2136     /* A malloc() may have failed within the call to sqlite3_value_text16()
2137     ** above. If this is the case, then the db->mallocFailed flag needs to
2138     ** be cleared before returning. Do this directly, instead of via
2139     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2140     */
2141     db->mallocFailed = 0;
2142   }
2143   sqlite3_mutex_leave(db->mutex);
2144   return z;
2145 }
2146 #endif /* SQLITE_OMIT_UTF16 */
2147 
2148 /*
2149 ** Return the most recent error code generated by an SQLite routine. If NULL is
2150 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2151 */
2152 int sqlite3_errcode(sqlite3 *db){
2153   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2154     return SQLITE_MISUSE_BKPT;
2155   }
2156   if( !db || db->mallocFailed ){
2157     return SQLITE_NOMEM;
2158   }
2159   return db->errCode & db->errMask;
2160 }
2161 int sqlite3_extended_errcode(sqlite3 *db){
2162   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2163     return SQLITE_MISUSE_BKPT;
2164   }
2165   if( !db || db->mallocFailed ){
2166     return SQLITE_NOMEM;
2167   }
2168   return db->errCode;
2169 }
2170 
2171 /*
2172 ** Return a string that describes the kind of error specified in the
2173 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2174 ** function.
2175 */
2176 const char *sqlite3_errstr(int rc){
2177   return sqlite3ErrStr(rc);
2178 }
2179 
2180 /*
2181 ** Create a new collating function for database "db".  The name is zName
2182 ** and the encoding is enc.
2183 */
2184 static int createCollation(
2185   sqlite3* db,
2186   const char *zName,
2187   u8 enc,
2188   void* pCtx,
2189   int(*xCompare)(void*,int,const void*,int,const void*),
2190   void(*xDel)(void*)
2191 ){
2192   CollSeq *pColl;
2193   int enc2;
2194 
2195   assert( sqlite3_mutex_held(db->mutex) );
2196 
2197   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2198   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2199   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2200   */
2201   enc2 = enc;
2202   testcase( enc2==SQLITE_UTF16 );
2203   testcase( enc2==SQLITE_UTF16_ALIGNED );
2204   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2205     enc2 = SQLITE_UTF16NATIVE;
2206   }
2207   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2208     return SQLITE_MISUSE_BKPT;
2209   }
2210 
2211   /* Check if this call is removing or replacing an existing collation
2212   ** sequence. If so, and there are active VMs, return busy. If there
2213   ** are no active VMs, invalidate any pre-compiled statements.
2214   */
2215   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2216   if( pColl && pColl->xCmp ){
2217     if( db->nVdbeActive ){
2218       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2219         "unable to delete/modify collation sequence due to active statements");
2220       return SQLITE_BUSY;
2221     }
2222     sqlite3ExpirePreparedStatements(db);
2223 
2224     /* If collation sequence pColl was created directly by a call to
2225     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2226     ** then any copies made by synthCollSeq() need to be invalidated.
2227     ** Also, collation destructor - CollSeq.xDel() - function may need
2228     ** to be called.
2229     */
2230     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2231       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2232       int j;
2233       for(j=0; j<3; j++){
2234         CollSeq *p = &aColl[j];
2235         if( p->enc==pColl->enc ){
2236           if( p->xDel ){
2237             p->xDel(p->pUser);
2238           }
2239           p->xCmp = 0;
2240         }
2241       }
2242     }
2243   }
2244 
2245   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2246   if( pColl==0 ) return SQLITE_NOMEM;
2247   pColl->xCmp = xCompare;
2248   pColl->pUser = pCtx;
2249   pColl->xDel = xDel;
2250   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2251   sqlite3Error(db, SQLITE_OK);
2252   return SQLITE_OK;
2253 }
2254 
2255 
2256 /*
2257 ** This array defines hard upper bounds on limit values.  The
2258 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2259 ** #defines in sqlite3.h.
2260 */
2261 static const int aHardLimit[] = {
2262   SQLITE_MAX_LENGTH,
2263   SQLITE_MAX_SQL_LENGTH,
2264   SQLITE_MAX_COLUMN,
2265   SQLITE_MAX_EXPR_DEPTH,
2266   SQLITE_MAX_COMPOUND_SELECT,
2267   SQLITE_MAX_VDBE_OP,
2268   SQLITE_MAX_FUNCTION_ARG,
2269   SQLITE_MAX_ATTACHED,
2270   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2271   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2272   SQLITE_MAX_TRIGGER_DEPTH,
2273   SQLITE_MAX_WORKER_THREADS,
2274 };
2275 
2276 /*
2277 ** Make sure the hard limits are set to reasonable values
2278 */
2279 #if SQLITE_MAX_LENGTH<100
2280 # error SQLITE_MAX_LENGTH must be at least 100
2281 #endif
2282 #if SQLITE_MAX_SQL_LENGTH<100
2283 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2284 #endif
2285 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2286 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2287 #endif
2288 #if SQLITE_MAX_COMPOUND_SELECT<2
2289 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2290 #endif
2291 #if SQLITE_MAX_VDBE_OP<40
2292 # error SQLITE_MAX_VDBE_OP must be at least 40
2293 #endif
2294 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
2295 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
2296 #endif
2297 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2298 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2299 #endif
2300 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2301 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2302 #endif
2303 #if SQLITE_MAX_COLUMN>32767
2304 # error SQLITE_MAX_COLUMN must not exceed 32767
2305 #endif
2306 #if SQLITE_MAX_TRIGGER_DEPTH<1
2307 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2308 #endif
2309 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2310 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2311 #endif
2312 
2313 
2314 /*
2315 ** Change the value of a limit.  Report the old value.
2316 ** If an invalid limit index is supplied, report -1.
2317 ** Make no changes but still report the old value if the
2318 ** new limit is negative.
2319 **
2320 ** A new lower limit does not shrink existing constructs.
2321 ** It merely prevents new constructs that exceed the limit
2322 ** from forming.
2323 */
2324 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2325   int oldLimit;
2326 
2327 #ifdef SQLITE_ENABLE_API_ARMOR
2328   if( !sqlite3SafetyCheckOk(db) ){
2329     (void)SQLITE_MISUSE_BKPT;
2330     return -1;
2331   }
2332 #endif
2333 
2334   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2335   ** there is a hard upper bound set at compile-time by a C preprocessor
2336   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2337   ** "_MAX_".)
2338   */
2339   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2340   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2341   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2342   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2343   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2344   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2345   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2346   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2347   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2348                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2349   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2350   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2351   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2352   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2353 
2354 
2355   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2356     return -1;
2357   }
2358   oldLimit = db->aLimit[limitId];
2359   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2360     if( newLimit>aHardLimit[limitId] ){
2361       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2362     }
2363     db->aLimit[limitId] = newLimit;
2364   }
2365   return oldLimit;                     /* IMP: R-53341-35419 */
2366 }
2367 
2368 /*
2369 ** This function is used to parse both URIs and non-URI filenames passed by the
2370 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2371 ** URIs specified as part of ATTACH statements.
2372 **
2373 ** The first argument to this function is the name of the VFS to use (or
2374 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2375 ** query parameter. The second argument contains the URI (or non-URI filename)
2376 ** itself. When this function is called the *pFlags variable should contain
2377 ** the default flags to open the database handle with. The value stored in
2378 ** *pFlags may be updated before returning if the URI filename contains
2379 ** "cache=xxx" or "mode=xxx" query parameters.
2380 **
2381 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2382 ** the VFS that should be used to open the database file. *pzFile is set to
2383 ** point to a buffer containing the name of the file to open. It is the
2384 ** responsibility of the caller to eventually call sqlite3_free() to release
2385 ** this buffer.
2386 **
2387 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2388 ** may be set to point to a buffer containing an English language error
2389 ** message. It is the responsibility of the caller to eventually release
2390 ** this buffer by calling sqlite3_free().
2391 */
2392 int sqlite3ParseUri(
2393   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2394   const char *zUri,               /* Nul-terminated URI to parse */
2395   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2396   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2397   char **pzFile,                  /* OUT: Filename component of URI */
2398   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2399 ){
2400   int rc = SQLITE_OK;
2401   unsigned int flags = *pFlags;
2402   const char *zVfs = zDefaultVfs;
2403   char *zFile;
2404   char c;
2405   int nUri = sqlite3Strlen30(zUri);
2406 
2407   assert( *pzErrMsg==0 );
2408 
2409   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2410             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2411    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2412   ){
2413     char *zOpt;
2414     int eState;                   /* Parser state when parsing URI */
2415     int iIn;                      /* Input character index */
2416     int iOut = 0;                 /* Output character index */
2417     int nByte = nUri+2;           /* Bytes of space to allocate */
2418 
2419     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2420     ** method that there may be extra parameters following the file-name.  */
2421     flags |= SQLITE_OPEN_URI;
2422 
2423     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2424     zFile = sqlite3_malloc(nByte);
2425     if( !zFile ) return SQLITE_NOMEM;
2426 
2427     iIn = 5;
2428 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2429     if( strncmp(zUri+5, "///", 3)==0 ){
2430       iIn = 7;
2431       /* The following condition causes URIs with five leading / characters
2432       ** like file://///host/path to be converted into UNCs like //host/path.
2433       ** The correct URI for that UNC has only two or four leading / characters
2434       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2435       ** common error, we are told, so we handle it as a special case. */
2436       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2437     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2438       iIn = 16;
2439     }
2440 #else
2441     /* Discard the scheme and authority segments of the URI. */
2442     if( zUri[5]=='/' && zUri[6]=='/' ){
2443       iIn = 7;
2444       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2445       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2446         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2447             iIn-7, &zUri[7]);
2448         rc = SQLITE_ERROR;
2449         goto parse_uri_out;
2450       }
2451     }
2452 #endif
2453 
2454     /* Copy the filename and any query parameters into the zFile buffer.
2455     ** Decode %HH escape codes along the way.
2456     **
2457     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2458     ** on the parsing context. As follows:
2459     **
2460     **   0: Parsing file-name.
2461     **   1: Parsing name section of a name=value query parameter.
2462     **   2: Parsing value section of a name=value query parameter.
2463     */
2464     eState = 0;
2465     while( (c = zUri[iIn])!=0 && c!='#' ){
2466       iIn++;
2467       if( c=='%'
2468        && sqlite3Isxdigit(zUri[iIn])
2469        && sqlite3Isxdigit(zUri[iIn+1])
2470       ){
2471         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2472         octet += sqlite3HexToInt(zUri[iIn++]);
2473 
2474         assert( octet>=0 && octet<256 );
2475         if( octet==0 ){
2476           /* This branch is taken when "%00" appears within the URI. In this
2477           ** case we ignore all text in the remainder of the path, name or
2478           ** value currently being parsed. So ignore the current character
2479           ** and skip to the next "?", "=" or "&", as appropriate. */
2480           while( (c = zUri[iIn])!=0 && c!='#'
2481               && (eState!=0 || c!='?')
2482               && (eState!=1 || (c!='=' && c!='&'))
2483               && (eState!=2 || c!='&')
2484           ){
2485             iIn++;
2486           }
2487           continue;
2488         }
2489         c = octet;
2490       }else if( eState==1 && (c=='&' || c=='=') ){
2491         if( zFile[iOut-1]==0 ){
2492           /* An empty option name. Ignore this option altogether. */
2493           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2494           continue;
2495         }
2496         if( c=='&' ){
2497           zFile[iOut++] = '\0';
2498         }else{
2499           eState = 2;
2500         }
2501         c = 0;
2502       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2503         c = 0;
2504         eState = 1;
2505       }
2506       zFile[iOut++] = c;
2507     }
2508     if( eState==1 ) zFile[iOut++] = '\0';
2509     zFile[iOut++] = '\0';
2510     zFile[iOut++] = '\0';
2511 
2512     /* Check if there were any options specified that should be interpreted
2513     ** here. Options that are interpreted here include "vfs" and those that
2514     ** correspond to flags that may be passed to the sqlite3_open_v2()
2515     ** method. */
2516     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2517     while( zOpt[0] ){
2518       int nOpt = sqlite3Strlen30(zOpt);
2519       char *zVal = &zOpt[nOpt+1];
2520       int nVal = sqlite3Strlen30(zVal);
2521 
2522       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2523         zVfs = zVal;
2524       }else{
2525         struct OpenMode {
2526           const char *z;
2527           int mode;
2528         } *aMode = 0;
2529         char *zModeType = 0;
2530         int mask = 0;
2531         int limit = 0;
2532 
2533         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2534           static struct OpenMode aCacheMode[] = {
2535             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2536             { "private", SQLITE_OPEN_PRIVATECACHE },
2537             { 0, 0 }
2538           };
2539 
2540           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2541           aMode = aCacheMode;
2542           limit = mask;
2543           zModeType = "cache";
2544         }
2545         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2546           static struct OpenMode aOpenMode[] = {
2547             { "ro",  SQLITE_OPEN_READONLY },
2548             { "rw",  SQLITE_OPEN_READWRITE },
2549             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2550             { "memory", SQLITE_OPEN_MEMORY },
2551             { 0, 0 }
2552           };
2553 
2554           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2555                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2556           aMode = aOpenMode;
2557           limit = mask & flags;
2558           zModeType = "access";
2559         }
2560 
2561         if( aMode ){
2562           int i;
2563           int mode = 0;
2564           for(i=0; aMode[i].z; i++){
2565             const char *z = aMode[i].z;
2566             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2567               mode = aMode[i].mode;
2568               break;
2569             }
2570           }
2571           if( mode==0 ){
2572             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2573             rc = SQLITE_ERROR;
2574             goto parse_uri_out;
2575           }
2576           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2577             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2578                                         zModeType, zVal);
2579             rc = SQLITE_PERM;
2580             goto parse_uri_out;
2581           }
2582           flags = (flags & ~mask) | mode;
2583         }
2584       }
2585 
2586       zOpt = &zVal[nVal+1];
2587     }
2588 
2589   }else{
2590     zFile = sqlite3_malloc(nUri+2);
2591     if( !zFile ) return SQLITE_NOMEM;
2592     memcpy(zFile, zUri, nUri);
2593     zFile[nUri] = '\0';
2594     zFile[nUri+1] = '\0';
2595     flags &= ~SQLITE_OPEN_URI;
2596   }
2597 
2598   *ppVfs = sqlite3_vfs_find(zVfs);
2599   if( *ppVfs==0 ){
2600     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2601     rc = SQLITE_ERROR;
2602   }
2603  parse_uri_out:
2604   if( rc!=SQLITE_OK ){
2605     sqlite3_free(zFile);
2606     zFile = 0;
2607   }
2608   *pFlags = flags;
2609   *pzFile = zFile;
2610   return rc;
2611 }
2612 
2613 
2614 /*
2615 ** This routine does the work of opening a database on behalf of
2616 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2617 ** is UTF-8 encoded.
2618 */
2619 static int openDatabase(
2620   const char *zFilename, /* Database filename UTF-8 encoded */
2621   sqlite3 **ppDb,        /* OUT: Returned database handle */
2622   unsigned int flags,    /* Operational flags */
2623   const char *zVfs       /* Name of the VFS to use */
2624 ){
2625   sqlite3 *db;                    /* Store allocated handle here */
2626   int rc;                         /* Return code */
2627   int isThreadsafe;               /* True for threadsafe connections */
2628   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2629   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2630 
2631 #ifdef SQLITE_ENABLE_API_ARMOR
2632   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2633 #endif
2634   *ppDb = 0;
2635 #ifndef SQLITE_OMIT_AUTOINIT
2636   rc = sqlite3_initialize();
2637   if( rc ) return rc;
2638 #endif
2639 
2640   /* Only allow sensible combinations of bits in the flags argument.
2641   ** Throw an error if any non-sense combination is used.  If we
2642   ** do not block illegal combinations here, it could trigger
2643   ** assert() statements in deeper layers.  Sensible combinations
2644   ** are:
2645   **
2646   **  1:  SQLITE_OPEN_READONLY
2647   **  2:  SQLITE_OPEN_READWRITE
2648   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2649   */
2650   assert( SQLITE_OPEN_READONLY  == 0x01 );
2651   assert( SQLITE_OPEN_READWRITE == 0x02 );
2652   assert( SQLITE_OPEN_CREATE    == 0x04 );
2653   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2654   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2655   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2656   if( ((1<<(flags&7)) & 0x46)==0 ){
2657     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2658   }
2659 
2660   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2661     isThreadsafe = 0;
2662   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2663     isThreadsafe = 0;
2664   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2665     isThreadsafe = 1;
2666   }else{
2667     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2668   }
2669   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2670     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2671   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2672     flags |= SQLITE_OPEN_SHAREDCACHE;
2673   }
2674 
2675   /* Remove harmful bits from the flags parameter
2676   **
2677   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2678   ** dealt with in the previous code block.  Besides these, the only
2679   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2680   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2681   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2682   ** off all other flags.
2683   */
2684   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2685                SQLITE_OPEN_EXCLUSIVE |
2686                SQLITE_OPEN_MAIN_DB |
2687                SQLITE_OPEN_TEMP_DB |
2688                SQLITE_OPEN_TRANSIENT_DB |
2689                SQLITE_OPEN_MAIN_JOURNAL |
2690                SQLITE_OPEN_TEMP_JOURNAL |
2691                SQLITE_OPEN_SUBJOURNAL |
2692                SQLITE_OPEN_MASTER_JOURNAL |
2693                SQLITE_OPEN_NOMUTEX |
2694                SQLITE_OPEN_FULLMUTEX |
2695                SQLITE_OPEN_WAL
2696              );
2697 
2698   /* Allocate the sqlite data structure */
2699   db = sqlite3MallocZero( sizeof(sqlite3) );
2700   if( db==0 ) goto opendb_out;
2701   if( isThreadsafe ){
2702     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2703     if( db->mutex==0 ){
2704       sqlite3_free(db);
2705       db = 0;
2706       goto opendb_out;
2707     }
2708   }
2709   sqlite3_mutex_enter(db->mutex);
2710   db->errMask = 0xff;
2711   db->nDb = 2;
2712   db->magic = SQLITE_MAGIC_BUSY;
2713   db->aDb = db->aDbStatic;
2714 
2715   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2716   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2717   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2718   db->autoCommit = 1;
2719   db->nextAutovac = -1;
2720   db->szMmap = sqlite3GlobalConfig.szMmap;
2721   db->nextPagesize = 0;
2722   db->nMaxSorterMmap = 0x7FFFFFFF;
2723   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2724 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2725                  | SQLITE_AutoIndex
2726 #endif
2727 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2728                  | SQLITE_CkptFullFSync
2729 #endif
2730 #if SQLITE_DEFAULT_FILE_FORMAT<4
2731                  | SQLITE_LegacyFileFmt
2732 #endif
2733 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2734                  | SQLITE_LoadExtension
2735 #endif
2736 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2737                  | SQLITE_RecTriggers
2738 #endif
2739 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2740                  | SQLITE_ForeignKeys
2741 #endif
2742 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2743                  | SQLITE_ReverseOrder
2744 #endif
2745       ;
2746   sqlite3HashInit(&db->aCollSeq);
2747 #ifndef SQLITE_OMIT_VIRTUALTABLE
2748   sqlite3HashInit(&db->aModule);
2749 #endif
2750 
2751   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2752   ** and UTF-16, so add a version for each to avoid any unnecessary
2753   ** conversions. The only error that can occur here is a malloc() failure.
2754   **
2755   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2756   ** functions:
2757   */
2758   createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
2759   createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
2760   createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
2761   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2762   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2763   if( db->mallocFailed ){
2764     goto opendb_out;
2765   }
2766   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2767   ** strings is BINARY.
2768   */
2769   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
2770   assert( db->pDfltColl!=0 );
2771 
2772   /* Parse the filename/URI argument. */
2773   db->openFlags = flags;
2774   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2775   if( rc!=SQLITE_OK ){
2776     if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
2777     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2778     sqlite3_free(zErrMsg);
2779     goto opendb_out;
2780   }
2781 
2782   /* Open the backend database driver */
2783   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2784                         flags | SQLITE_OPEN_MAIN_DB);
2785   if( rc!=SQLITE_OK ){
2786     if( rc==SQLITE_IOERR_NOMEM ){
2787       rc = SQLITE_NOMEM;
2788     }
2789     sqlite3Error(db, rc);
2790     goto opendb_out;
2791   }
2792   sqlite3BtreeEnter(db->aDb[0].pBt);
2793   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2794   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2795   sqlite3BtreeLeave(db->aDb[0].pBt);
2796   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2797 
2798   /* The default safety_level for the main database is 'full'; for the temp
2799   ** database it is 'NONE'. This matches the pager layer defaults.
2800   */
2801   db->aDb[0].zName = "main";
2802   db->aDb[0].safety_level = 3;
2803   db->aDb[1].zName = "temp";
2804   db->aDb[1].safety_level = 1;
2805 
2806   db->magic = SQLITE_MAGIC_OPEN;
2807   if( db->mallocFailed ){
2808     goto opendb_out;
2809   }
2810 
2811   /* Register all built-in functions, but do not attempt to read the
2812   ** database schema yet. This is delayed until the first time the database
2813   ** is accessed.
2814   */
2815   sqlite3Error(db, SQLITE_OK);
2816   sqlite3RegisterBuiltinFunctions(db);
2817 
2818   /* Load automatic extensions - extensions that have been registered
2819   ** using the sqlite3_automatic_extension() API.
2820   */
2821   rc = sqlite3_errcode(db);
2822   if( rc==SQLITE_OK ){
2823     sqlite3AutoLoadExtensions(db);
2824     rc = sqlite3_errcode(db);
2825     if( rc!=SQLITE_OK ){
2826       goto opendb_out;
2827     }
2828   }
2829 
2830 #ifdef SQLITE_ENABLE_FTS1
2831   if( !db->mallocFailed ){
2832     extern int sqlite3Fts1Init(sqlite3*);
2833     rc = sqlite3Fts1Init(db);
2834   }
2835 #endif
2836 
2837 #ifdef SQLITE_ENABLE_FTS2
2838   if( !db->mallocFailed && rc==SQLITE_OK ){
2839     extern int sqlite3Fts2Init(sqlite3*);
2840     rc = sqlite3Fts2Init(db);
2841   }
2842 #endif
2843 
2844 #ifdef SQLITE_ENABLE_FTS3
2845   if( !db->mallocFailed && rc==SQLITE_OK ){
2846     rc = sqlite3Fts3Init(db);
2847   }
2848 #endif
2849 
2850 #ifdef SQLITE_ENABLE_ICU
2851   if( !db->mallocFailed && rc==SQLITE_OK ){
2852     rc = sqlite3IcuInit(db);
2853   }
2854 #endif
2855 
2856 #ifdef SQLITE_ENABLE_RTREE
2857   if( !db->mallocFailed && rc==SQLITE_OK){
2858     rc = sqlite3RtreeInit(db);
2859   }
2860 #endif
2861 
2862   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2863   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2864   ** mode.  Doing nothing at all also makes NORMAL the default.
2865   */
2866 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2867   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2868   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2869                           SQLITE_DEFAULT_LOCKING_MODE);
2870 #endif
2871 
2872   if( rc ) sqlite3Error(db, rc);
2873 
2874   /* Enable the lookaside-malloc subsystem */
2875   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2876                         sqlite3GlobalConfig.nLookaside);
2877 
2878   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2879 
2880 opendb_out:
2881   sqlite3_free(zOpen);
2882   if( db ){
2883     assert( db->mutex!=0 || isThreadsafe==0
2884            || sqlite3GlobalConfig.bFullMutex==0 );
2885     sqlite3_mutex_leave(db->mutex);
2886   }
2887   rc = sqlite3_errcode(db);
2888   assert( db!=0 || rc==SQLITE_NOMEM );
2889   if( rc==SQLITE_NOMEM ){
2890     sqlite3_close(db);
2891     db = 0;
2892   }else if( rc!=SQLITE_OK ){
2893     db->magic = SQLITE_MAGIC_SICK;
2894   }
2895   *ppDb = db;
2896 #ifdef SQLITE_ENABLE_SQLLOG
2897   if( sqlite3GlobalConfig.xSqllog ){
2898     /* Opening a db handle. Fourth parameter is passed 0. */
2899     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2900     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2901   }
2902 #endif
2903   return sqlite3ApiExit(0, rc);
2904 }
2905 
2906 /*
2907 ** Open a new database handle.
2908 */
2909 int sqlite3_open(
2910   const char *zFilename,
2911   sqlite3 **ppDb
2912 ){
2913   return openDatabase(zFilename, ppDb,
2914                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2915 }
2916 int sqlite3_open_v2(
2917   const char *filename,   /* Database filename (UTF-8) */
2918   sqlite3 **ppDb,         /* OUT: SQLite db handle */
2919   int flags,              /* Flags */
2920   const char *zVfs        /* Name of VFS module to use */
2921 ){
2922   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
2923 }
2924 
2925 #ifndef SQLITE_OMIT_UTF16
2926 /*
2927 ** Open a new database handle.
2928 */
2929 int sqlite3_open16(
2930   const void *zFilename,
2931   sqlite3 **ppDb
2932 ){
2933   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
2934   sqlite3_value *pVal;
2935   int rc;
2936 
2937 #ifdef SQLITE_ENABLE_API_ARMOR
2938   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2939 #endif
2940   *ppDb = 0;
2941 #ifndef SQLITE_OMIT_AUTOINIT
2942   rc = sqlite3_initialize();
2943   if( rc ) return rc;
2944 #endif
2945   if( zFilename==0 ) zFilename = "\000\000";
2946   pVal = sqlite3ValueNew(0);
2947   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
2948   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
2949   if( zFilename8 ){
2950     rc = openDatabase(zFilename8, ppDb,
2951                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2952     assert( *ppDb || rc==SQLITE_NOMEM );
2953     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
2954       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
2955     }
2956   }else{
2957     rc = SQLITE_NOMEM;
2958   }
2959   sqlite3ValueFree(pVal);
2960 
2961   return sqlite3ApiExit(0, rc);
2962 }
2963 #endif /* SQLITE_OMIT_UTF16 */
2964 
2965 /*
2966 ** Register a new collation sequence with the database handle db.
2967 */
2968 int sqlite3_create_collation(
2969   sqlite3* db,
2970   const char *zName,
2971   int enc,
2972   void* pCtx,
2973   int(*xCompare)(void*,int,const void*,int,const void*)
2974 ){
2975   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
2976 }
2977 
2978 /*
2979 ** Register a new collation sequence with the database handle db.
2980 */
2981 int sqlite3_create_collation_v2(
2982   sqlite3* db,
2983   const char *zName,
2984   int enc,
2985   void* pCtx,
2986   int(*xCompare)(void*,int,const void*,int,const void*),
2987   void(*xDel)(void*)
2988 ){
2989   int rc;
2990 
2991 #ifdef SQLITE_ENABLE_API_ARMOR
2992   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
2993 #endif
2994   sqlite3_mutex_enter(db->mutex);
2995   assert( !db->mallocFailed );
2996   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
2997   rc = sqlite3ApiExit(db, rc);
2998   sqlite3_mutex_leave(db->mutex);
2999   return rc;
3000 }
3001 
3002 #ifndef SQLITE_OMIT_UTF16
3003 /*
3004 ** Register a new collation sequence with the database handle db.
3005 */
3006 int sqlite3_create_collation16(
3007   sqlite3* db,
3008   const void *zName,
3009   int enc,
3010   void* pCtx,
3011   int(*xCompare)(void*,int,const void*,int,const void*)
3012 ){
3013   int rc = SQLITE_OK;
3014   char *zName8;
3015 
3016 #ifdef SQLITE_ENABLE_API_ARMOR
3017   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3018 #endif
3019   sqlite3_mutex_enter(db->mutex);
3020   assert( !db->mallocFailed );
3021   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3022   if( zName8 ){
3023     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3024     sqlite3DbFree(db, zName8);
3025   }
3026   rc = sqlite3ApiExit(db, rc);
3027   sqlite3_mutex_leave(db->mutex);
3028   return rc;
3029 }
3030 #endif /* SQLITE_OMIT_UTF16 */
3031 
3032 /*
3033 ** Register a collation sequence factory callback with the database handle
3034 ** db. Replace any previously installed collation sequence factory.
3035 */
3036 int sqlite3_collation_needed(
3037   sqlite3 *db,
3038   void *pCollNeededArg,
3039   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3040 ){
3041 #ifdef SQLITE_ENABLE_API_ARMOR
3042   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3043 #endif
3044   sqlite3_mutex_enter(db->mutex);
3045   db->xCollNeeded = xCollNeeded;
3046   db->xCollNeeded16 = 0;
3047   db->pCollNeededArg = pCollNeededArg;
3048   sqlite3_mutex_leave(db->mutex);
3049   return SQLITE_OK;
3050 }
3051 
3052 #ifndef SQLITE_OMIT_UTF16
3053 /*
3054 ** Register a collation sequence factory callback with the database handle
3055 ** db. Replace any previously installed collation sequence factory.
3056 */
3057 int sqlite3_collation_needed16(
3058   sqlite3 *db,
3059   void *pCollNeededArg,
3060   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3061 ){
3062 #ifdef SQLITE_ENABLE_API_ARMOR
3063   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3064 #endif
3065   sqlite3_mutex_enter(db->mutex);
3066   db->xCollNeeded = 0;
3067   db->xCollNeeded16 = xCollNeeded16;
3068   db->pCollNeededArg = pCollNeededArg;
3069   sqlite3_mutex_leave(db->mutex);
3070   return SQLITE_OK;
3071 }
3072 #endif /* SQLITE_OMIT_UTF16 */
3073 
3074 #ifndef SQLITE_OMIT_DEPRECATED
3075 /*
3076 ** This function is now an anachronism. It used to be used to recover from a
3077 ** malloc() failure, but SQLite now does this automatically.
3078 */
3079 int sqlite3_global_recover(void){
3080   return SQLITE_OK;
3081 }
3082 #endif
3083 
3084 /*
3085 ** Test to see whether or not the database connection is in autocommit
3086 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3087 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3088 ** by the next COMMIT or ROLLBACK.
3089 */
3090 int sqlite3_get_autocommit(sqlite3 *db){
3091 #ifdef SQLITE_ENABLE_API_ARMOR
3092   if( !sqlite3SafetyCheckOk(db) ){
3093     (void)SQLITE_MISUSE_BKPT;
3094     return 0;
3095   }
3096 #endif
3097   return db->autoCommit;
3098 }
3099 
3100 /*
3101 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3102 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
3103 ** constants.  They serve two purposes:
3104 **
3105 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3106 **       to detect when version error conditions occurs.
3107 **
3108 **   2.  Invoke sqlite3_log() to provide the source code location where
3109 **       a low-level error is first detected.
3110 */
3111 int sqlite3CorruptError(int lineno){
3112   testcase( sqlite3GlobalConfig.xLog!=0 );
3113   sqlite3_log(SQLITE_CORRUPT,
3114               "database corruption at line %d of [%.10s]",
3115               lineno, 20+sqlite3_sourceid());
3116   return SQLITE_CORRUPT;
3117 }
3118 int sqlite3MisuseError(int lineno){
3119   testcase( sqlite3GlobalConfig.xLog!=0 );
3120   sqlite3_log(SQLITE_MISUSE,
3121               "misuse at line %d of [%.10s]",
3122               lineno, 20+sqlite3_sourceid());
3123   return SQLITE_MISUSE;
3124 }
3125 int sqlite3CantopenError(int lineno){
3126   testcase( sqlite3GlobalConfig.xLog!=0 );
3127   sqlite3_log(SQLITE_CANTOPEN,
3128               "cannot open file at line %d of [%.10s]",
3129               lineno, 20+sqlite3_sourceid());
3130   return SQLITE_CANTOPEN;
3131 }
3132 
3133 
3134 #ifndef SQLITE_OMIT_DEPRECATED
3135 /*
3136 ** This is a convenience routine that makes sure that all thread-specific
3137 ** data for this thread has been deallocated.
3138 **
3139 ** SQLite no longer uses thread-specific data so this routine is now a
3140 ** no-op.  It is retained for historical compatibility.
3141 */
3142 void sqlite3_thread_cleanup(void){
3143 }
3144 #endif
3145 
3146 /*
3147 ** Return meta information about a specific column of a database table.
3148 ** See comment in sqlite3.h (sqlite.h.in) for details.
3149 */
3150 int sqlite3_table_column_metadata(
3151   sqlite3 *db,                /* Connection handle */
3152   const char *zDbName,        /* Database name or NULL */
3153   const char *zTableName,     /* Table name */
3154   const char *zColumnName,    /* Column name */
3155   char const **pzDataType,    /* OUTPUT: Declared data type */
3156   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3157   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3158   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3159   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3160 ){
3161   int rc;
3162   char *zErrMsg = 0;
3163   Table *pTab = 0;
3164   Column *pCol = 0;
3165   int iCol = 0;
3166   char const *zDataType = 0;
3167   char const *zCollSeq = 0;
3168   int notnull = 0;
3169   int primarykey = 0;
3170   int autoinc = 0;
3171 
3172 
3173 #ifdef SQLITE_ENABLE_API_ARMOR
3174   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3175     return SQLITE_MISUSE_BKPT;
3176   }
3177 #endif
3178 
3179   /* Ensure the database schema has been loaded */
3180   sqlite3_mutex_enter(db->mutex);
3181   sqlite3BtreeEnterAll(db);
3182   rc = sqlite3Init(db, &zErrMsg);
3183   if( SQLITE_OK!=rc ){
3184     goto error_out;
3185   }
3186 
3187   /* Locate the table in question */
3188   pTab = sqlite3FindTable(db, zTableName, zDbName);
3189   if( !pTab || pTab->pSelect ){
3190     pTab = 0;
3191     goto error_out;
3192   }
3193 
3194   /* Find the column for which info is requested */
3195   if( zColumnName==0 ){
3196     /* Query for existance of table only */
3197   }else{
3198     for(iCol=0; iCol<pTab->nCol; iCol++){
3199       pCol = &pTab->aCol[iCol];
3200       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3201         break;
3202       }
3203     }
3204     if( iCol==pTab->nCol ){
3205       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3206         iCol = pTab->iPKey;
3207         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3208       }else{
3209         pTab = 0;
3210         goto error_out;
3211       }
3212     }
3213   }
3214 
3215   /* The following block stores the meta information that will be returned
3216   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3217   ** and autoinc. At this point there are two possibilities:
3218   **
3219   **     1. The specified column name was rowid", "oid" or "_rowid_"
3220   **        and there is no explicitly declared IPK column.
3221   **
3222   **     2. The table is not a view and the column name identified an
3223   **        explicitly declared column. Copy meta information from *pCol.
3224   */
3225   if( pCol ){
3226     zDataType = pCol->zType;
3227     zCollSeq = pCol->zColl;
3228     notnull = pCol->notNull!=0;
3229     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3230     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3231   }else{
3232     zDataType = "INTEGER";
3233     primarykey = 1;
3234   }
3235   if( !zCollSeq ){
3236     zCollSeq = "BINARY";
3237   }
3238 
3239 error_out:
3240   sqlite3BtreeLeaveAll(db);
3241 
3242   /* Whether the function call succeeded or failed, set the output parameters
3243   ** to whatever their local counterparts contain. If an error did occur,
3244   ** this has the effect of zeroing all output parameters.
3245   */
3246   if( pzDataType ) *pzDataType = zDataType;
3247   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3248   if( pNotNull ) *pNotNull = notnull;
3249   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3250   if( pAutoinc ) *pAutoinc = autoinc;
3251 
3252   if( SQLITE_OK==rc && !pTab ){
3253     sqlite3DbFree(db, zErrMsg);
3254     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3255         zColumnName);
3256     rc = SQLITE_ERROR;
3257   }
3258   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3259   sqlite3DbFree(db, zErrMsg);
3260   rc = sqlite3ApiExit(db, rc);
3261   sqlite3_mutex_leave(db->mutex);
3262   return rc;
3263 }
3264 
3265 /*
3266 ** Sleep for a little while.  Return the amount of time slept.
3267 */
3268 int sqlite3_sleep(int ms){
3269   sqlite3_vfs *pVfs;
3270   int rc;
3271   pVfs = sqlite3_vfs_find(0);
3272   if( pVfs==0 ) return 0;
3273 
3274   /* This function works in milliseconds, but the underlying OsSleep()
3275   ** API uses microseconds. Hence the 1000's.
3276   */
3277   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3278   return rc;
3279 }
3280 
3281 /*
3282 ** Enable or disable the extended result codes.
3283 */
3284 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3285 #ifdef SQLITE_ENABLE_API_ARMOR
3286   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3287 #endif
3288   sqlite3_mutex_enter(db->mutex);
3289   db->errMask = onoff ? 0xffffffff : 0xff;
3290   sqlite3_mutex_leave(db->mutex);
3291   return SQLITE_OK;
3292 }
3293 
3294 /*
3295 ** Invoke the xFileControl method on a particular database.
3296 */
3297 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3298   int rc = SQLITE_ERROR;
3299   Btree *pBtree;
3300 
3301 #ifdef SQLITE_ENABLE_API_ARMOR
3302   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3303 #endif
3304   sqlite3_mutex_enter(db->mutex);
3305   pBtree = sqlite3DbNameToBtree(db, zDbName);
3306   if( pBtree ){
3307     Pager *pPager;
3308     sqlite3_file *fd;
3309     sqlite3BtreeEnter(pBtree);
3310     pPager = sqlite3BtreePager(pBtree);
3311     assert( pPager!=0 );
3312     fd = sqlite3PagerFile(pPager);
3313     assert( fd!=0 );
3314     if( op==SQLITE_FCNTL_FILE_POINTER ){
3315       *(sqlite3_file**)pArg = fd;
3316       rc = SQLITE_OK;
3317     }else if( fd->pMethods ){
3318       rc = sqlite3OsFileControl(fd, op, pArg);
3319     }else{
3320       rc = SQLITE_NOTFOUND;
3321     }
3322     sqlite3BtreeLeave(pBtree);
3323   }
3324   sqlite3_mutex_leave(db->mutex);
3325   return rc;
3326 }
3327 
3328 /*
3329 ** Interface to the testing logic.
3330 */
3331 int sqlite3_test_control(int op, ...){
3332   int rc = 0;
3333 #ifndef SQLITE_OMIT_BUILTIN_TEST
3334   va_list ap;
3335   va_start(ap, op);
3336   switch( op ){
3337 
3338     /*
3339     ** Save the current state of the PRNG.
3340     */
3341     case SQLITE_TESTCTRL_PRNG_SAVE: {
3342       sqlite3PrngSaveState();
3343       break;
3344     }
3345 
3346     /*
3347     ** Restore the state of the PRNG to the last state saved using
3348     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3349     ** this verb acts like PRNG_RESET.
3350     */
3351     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3352       sqlite3PrngRestoreState();
3353       break;
3354     }
3355 
3356     /*
3357     ** Reset the PRNG back to its uninitialized state.  The next call
3358     ** to sqlite3_randomness() will reseed the PRNG using a single call
3359     ** to the xRandomness method of the default VFS.
3360     */
3361     case SQLITE_TESTCTRL_PRNG_RESET: {
3362       sqlite3_randomness(0,0);
3363       break;
3364     }
3365 
3366     /*
3367     **  sqlite3_test_control(BITVEC_TEST, size, program)
3368     **
3369     ** Run a test against a Bitvec object of size.  The program argument
3370     ** is an array of integers that defines the test.  Return -1 on a
3371     ** memory allocation error, 0 on success, or non-zero for an error.
3372     ** See the sqlite3BitvecBuiltinTest() for additional information.
3373     */
3374     case SQLITE_TESTCTRL_BITVEC_TEST: {
3375       int sz = va_arg(ap, int);
3376       int *aProg = va_arg(ap, int*);
3377       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3378       break;
3379     }
3380 
3381     /*
3382     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3383     **
3384     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3385     ** if xCallback is not NULL.
3386     **
3387     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3388     ** is called immediately after installing the new callback and the return
3389     ** value from sqlite3FaultSim(0) becomes the return from
3390     ** sqlite3_test_control().
3391     */
3392     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3393       /* MSVC is picky about pulling func ptrs from va lists.
3394       ** http://support.microsoft.com/kb/47961
3395       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3396       */
3397       typedef int(*TESTCALLBACKFUNC_t)(int);
3398       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3399       rc = sqlite3FaultSim(0);
3400       break;
3401     }
3402 
3403     /*
3404     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3405     **
3406     ** Register hooks to call to indicate which malloc() failures
3407     ** are benign.
3408     */
3409     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3410       typedef void (*void_function)(void);
3411       void_function xBenignBegin;
3412       void_function xBenignEnd;
3413       xBenignBegin = va_arg(ap, void_function);
3414       xBenignEnd = va_arg(ap, void_function);
3415       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3416       break;
3417     }
3418 
3419     /*
3420     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3421     **
3422     ** Set the PENDING byte to the value in the argument, if X>0.
3423     ** Make no changes if X==0.  Return the value of the pending byte
3424     ** as it existing before this routine was called.
3425     **
3426     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3427     ** an incompatible database file format.  Changing the PENDING byte
3428     ** while any database connection is open results in undefined and
3429     ** deleterious behavior.
3430     */
3431     case SQLITE_TESTCTRL_PENDING_BYTE: {
3432       rc = PENDING_BYTE;
3433 #ifndef SQLITE_OMIT_WSD
3434       {
3435         unsigned int newVal = va_arg(ap, unsigned int);
3436         if( newVal ) sqlite3PendingByte = newVal;
3437       }
3438 #endif
3439       break;
3440     }
3441 
3442     /*
3443     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3444     **
3445     ** This action provides a run-time test to see whether or not
3446     ** assert() was enabled at compile-time.  If X is true and assert()
3447     ** is enabled, then the return value is true.  If X is true and
3448     ** assert() is disabled, then the return value is zero.  If X is
3449     ** false and assert() is enabled, then the assertion fires and the
3450     ** process aborts.  If X is false and assert() is disabled, then the
3451     ** return value is zero.
3452     */
3453     case SQLITE_TESTCTRL_ASSERT: {
3454       volatile int x = 0;
3455       assert( (x = va_arg(ap,int))!=0 );
3456       rc = x;
3457       break;
3458     }
3459 
3460 
3461     /*
3462     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3463     **
3464     ** This action provides a run-time test to see how the ALWAYS and
3465     ** NEVER macros were defined at compile-time.
3466     **
3467     ** The return value is ALWAYS(X).
3468     **
3469     ** The recommended test is X==2.  If the return value is 2, that means
3470     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3471     ** default setting.  If the return value is 1, then ALWAYS() is either
3472     ** hard-coded to true or else it asserts if its argument is false.
3473     ** The first behavior (hard-coded to true) is the case if
3474     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3475     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3476     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3477     **
3478     ** The run-time test procedure might look something like this:
3479     **
3480     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3481     **      // ALWAYS() and NEVER() are no-op pass-through macros
3482     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3483     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3484     **    }else{
3485     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3486     **    }
3487     */
3488     case SQLITE_TESTCTRL_ALWAYS: {
3489       int x = va_arg(ap,int);
3490       rc = ALWAYS(x);
3491       break;
3492     }
3493 
3494     /*
3495     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3496     **
3497     ** The integer returned reveals the byte-order of the computer on which
3498     ** SQLite is running:
3499     **
3500     **       1     big-endian,    determined at run-time
3501     **      10     little-endian, determined at run-time
3502     **  432101     big-endian,    determined at compile-time
3503     **  123410     little-endian, determined at compile-time
3504     */
3505     case SQLITE_TESTCTRL_BYTEORDER: {
3506       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3507       break;
3508     }
3509 
3510     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3511     **
3512     ** Set the nReserve size to N for the main database on the database
3513     ** connection db.
3514     */
3515     case SQLITE_TESTCTRL_RESERVE: {
3516       sqlite3 *db = va_arg(ap, sqlite3*);
3517       int x = va_arg(ap,int);
3518       sqlite3_mutex_enter(db->mutex);
3519       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3520       sqlite3_mutex_leave(db->mutex);
3521       break;
3522     }
3523 
3524     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3525     **
3526     ** Enable or disable various optimizations for testing purposes.  The
3527     ** argument N is a bitmask of optimizations to be disabled.  For normal
3528     ** operation N should be 0.  The idea is that a test program (like the
3529     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3530     ** with various optimizations disabled to verify that the same answer
3531     ** is obtained in every case.
3532     */
3533     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3534       sqlite3 *db = va_arg(ap, sqlite3*);
3535       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3536       break;
3537     }
3538 
3539 #ifdef SQLITE_N_KEYWORD
3540     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3541     **
3542     ** If zWord is a keyword recognized by the parser, then return the
3543     ** number of keywords.  Or if zWord is not a keyword, return 0.
3544     **
3545     ** This test feature is only available in the amalgamation since
3546     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3547     ** is built using separate source files.
3548     */
3549     case SQLITE_TESTCTRL_ISKEYWORD: {
3550       const char *zWord = va_arg(ap, const char*);
3551       int n = sqlite3Strlen30(zWord);
3552       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3553       break;
3554     }
3555 #endif
3556 
3557     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3558     **
3559     ** Pass pFree into sqlite3ScratchFree().
3560     ** If sz>0 then allocate a scratch buffer into pNew.
3561     */
3562     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3563       void *pFree, **ppNew;
3564       int sz;
3565       sz = va_arg(ap, int);
3566       ppNew = va_arg(ap, void**);
3567       pFree = va_arg(ap, void*);
3568       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3569       sqlite3ScratchFree(pFree);
3570       break;
3571     }
3572 
3573     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3574     **
3575     ** If parameter onoff is non-zero, configure the wrappers so that all
3576     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3577     ** undo this setting.
3578     */
3579     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3580       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3581       break;
3582     }
3583 
3584     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3585     **
3586     ** Set or clear a flag that indicates that the database file is always well-
3587     ** formed and never corrupt.  This flag is clear by default, indicating that
3588     ** database files might have arbitrary corruption.  Setting the flag during
3589     ** testing causes certain assert() statements in the code to be activated
3590     ** that demonstrat invariants on well-formed database files.
3591     */
3592     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3593       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3594       break;
3595     }
3596 
3597 
3598     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3599     **
3600     ** Set the VDBE coverage callback function to xCallback with context
3601     ** pointer ptr.
3602     */
3603     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3604 #ifdef SQLITE_VDBE_COVERAGE
3605       typedef void (*branch_callback)(void*,int,u8,u8);
3606       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3607       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3608 #endif
3609       break;
3610     }
3611 
3612     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3613     case SQLITE_TESTCTRL_SORTER_MMAP: {
3614       sqlite3 *db = va_arg(ap, sqlite3*);
3615       db->nMaxSorterMmap = va_arg(ap, int);
3616       break;
3617     }
3618 
3619     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3620     **
3621     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3622     ** not.
3623     */
3624     case SQLITE_TESTCTRL_ISINIT: {
3625       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3626       break;
3627     }
3628 
3629     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3630     **
3631     ** This test control is used to create imposter tables.  "db" is a pointer
3632     ** to the database connection.  dbName is the database name (ex: "main" or
3633     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3634     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3635     ** table should connect.
3636     **
3637     ** Enable imposter mode only when the schema has already been parsed.  Then
3638     ** run a single CREATE TABLE statement to construct the imposter table in
3639     ** the parsed schema.  Then turn imposter mode back off again.
3640     **
3641     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3642     ** the schema to be reparsed the next time it is needed.  This has the
3643     ** effect of erasing all imposter tables.
3644     */
3645     case SQLITE_TESTCTRL_IMPOSTER: {
3646       sqlite3 *db = va_arg(ap, sqlite3*);
3647       sqlite3_mutex_enter(db->mutex);
3648       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3649       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3650       db->init.newTnum = va_arg(ap,int);
3651       if( db->init.busy==0 && db->init.newTnum>0 ){
3652         sqlite3ResetAllSchemasOfConnection(db);
3653       }
3654       sqlite3_mutex_leave(db->mutex);
3655       break;
3656     }
3657   }
3658   va_end(ap);
3659 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3660   return rc;
3661 }
3662 
3663 /*
3664 ** This is a utility routine, useful to VFS implementations, that checks
3665 ** to see if a database file was a URI that contained a specific query
3666 ** parameter, and if so obtains the value of the query parameter.
3667 **
3668 ** The zFilename argument is the filename pointer passed into the xOpen()
3669 ** method of a VFS implementation.  The zParam argument is the name of the
3670 ** query parameter we seek.  This routine returns the value of the zParam
3671 ** parameter if it exists.  If the parameter does not exist, this routine
3672 ** returns a NULL pointer.
3673 */
3674 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3675   if( zFilename==0 || zParam==0 ) return 0;
3676   zFilename += sqlite3Strlen30(zFilename) + 1;
3677   while( zFilename[0] ){
3678     int x = strcmp(zFilename, zParam);
3679     zFilename += sqlite3Strlen30(zFilename) + 1;
3680     if( x==0 ) return zFilename;
3681     zFilename += sqlite3Strlen30(zFilename) + 1;
3682   }
3683   return 0;
3684 }
3685 
3686 /*
3687 ** Return a boolean value for a query parameter.
3688 */
3689 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3690   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3691   bDflt = bDflt!=0;
3692   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3693 }
3694 
3695 /*
3696 ** Return a 64-bit integer value for a query parameter.
3697 */
3698 sqlite3_int64 sqlite3_uri_int64(
3699   const char *zFilename,    /* Filename as passed to xOpen */
3700   const char *zParam,       /* URI parameter sought */
3701   sqlite3_int64 bDflt       /* return if parameter is missing */
3702 ){
3703   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3704   sqlite3_int64 v;
3705   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3706     bDflt = v;
3707   }
3708   return bDflt;
3709 }
3710 
3711 /*
3712 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3713 */
3714 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3715   int i;
3716   for(i=0; i<db->nDb; i++){
3717     if( db->aDb[i].pBt
3718      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3719     ){
3720       return db->aDb[i].pBt;
3721     }
3722   }
3723   return 0;
3724 }
3725 
3726 /*
3727 ** Return the filename of the database associated with a database
3728 ** connection.
3729 */
3730 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3731   Btree *pBt;
3732 #ifdef SQLITE_ENABLE_API_ARMOR
3733   if( !sqlite3SafetyCheckOk(db) ){
3734     (void)SQLITE_MISUSE_BKPT;
3735     return 0;
3736   }
3737 #endif
3738   pBt = sqlite3DbNameToBtree(db, zDbName);
3739   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3740 }
3741 
3742 /*
3743 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3744 ** no such database exists.
3745 */
3746 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3747   Btree *pBt;
3748 #ifdef SQLITE_ENABLE_API_ARMOR
3749   if( !sqlite3SafetyCheckOk(db) ){
3750     (void)SQLITE_MISUSE_BKPT;
3751     return -1;
3752   }
3753 #endif
3754   pBt = sqlite3DbNameToBtree(db, zDbName);
3755   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3756 }
3757