xref: /sqlite-3.40.0/src/main.c (revision 8dfde89b)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Main file for the SQLite library.  The routines in this file
13 ** implement the programmer interface to the library.  Routines in
14 ** other files are for internal use by SQLite and should not be
15 ** accessed by users of the library.
16 */
17 #include "sqliteInt.h"
18 
19 #ifdef SQLITE_ENABLE_FTS3
20 # include "fts3.h"
21 #endif
22 #ifdef SQLITE_ENABLE_RTREE
23 # include "rtree.h"
24 #endif
25 #ifdef SQLITE_ENABLE_ICU
26 # include "sqliteicu.h"
27 #endif
28 #ifdef SQLITE_ENABLE_JSON1
29 int sqlite3Json1Init(sqlite3*);
30 #endif
31 #ifdef SQLITE_ENABLE_STMTVTAB
32 int sqlite3StmtVtabInit(sqlite3*);
33 #endif
34 #ifdef SQLITE_ENABLE_FTS5
35 int sqlite3Fts5Init(sqlite3*);
36 #endif
37 
38 #ifndef SQLITE_AMALGAMATION
39 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
40 ** contains the text of SQLITE_VERSION macro.
41 */
42 const char sqlite3_version[] = SQLITE_VERSION;
43 #endif
44 
45 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
46 ** a pointer to the to the sqlite3_version[] string constant.
47 */
48 const char *sqlite3_libversion(void){ return sqlite3_version; }
49 
50 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
51 ** pointer to a string constant whose value is the same as the
52 ** SQLITE_SOURCE_ID C preprocessor macro.
53 */
54 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
55 
56 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
57 ** returns an integer equal to SQLITE_VERSION_NUMBER.
58 */
59 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
60 
61 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
62 ** zero if and only if SQLite was compiled with mutexing code omitted due to
63 ** the SQLITE_THREADSAFE compile-time option being set to 0.
64 */
65 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
66 
67 /*
68 ** When compiling the test fixture or with debugging enabled (on Win32),
69 ** this variable being set to non-zero will cause OSTRACE macros to emit
70 ** extra diagnostic information.
71 */
72 #ifdef SQLITE_HAVE_OS_TRACE
73 # ifndef SQLITE_DEBUG_OS_TRACE
74 #   define SQLITE_DEBUG_OS_TRACE 0
75 # endif
76   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
77 #endif
78 
79 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
80 /*
81 ** If the following function pointer is not NULL and if
82 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
83 ** I/O active are written using this function.  These messages
84 ** are intended for debugging activity only.
85 */
86 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
87 #endif
88 
89 /*
90 ** If the following global variable points to a string which is the
91 ** name of a directory, then that directory will be used to store
92 ** temporary files.
93 **
94 ** See also the "PRAGMA temp_store_directory" SQL command.
95 */
96 char *sqlite3_temp_directory = 0;
97 
98 /*
99 ** If the following global variable points to a string which is the
100 ** name of a directory, then that directory will be used to store
101 ** all database files specified with a relative pathname.
102 **
103 ** See also the "PRAGMA data_store_directory" SQL command.
104 */
105 char *sqlite3_data_directory = 0;
106 
107 /*
108 ** Initialize SQLite.
109 **
110 ** This routine must be called to initialize the memory allocation,
111 ** VFS, and mutex subsystems prior to doing any serious work with
112 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
113 ** this routine will be called automatically by key routines such as
114 ** sqlite3_open().
115 **
116 ** This routine is a no-op except on its very first call for the process,
117 ** or for the first call after a call to sqlite3_shutdown.
118 **
119 ** The first thread to call this routine runs the initialization to
120 ** completion.  If subsequent threads call this routine before the first
121 ** thread has finished the initialization process, then the subsequent
122 ** threads must block until the first thread finishes with the initialization.
123 **
124 ** The first thread might call this routine recursively.  Recursive
125 ** calls to this routine should not block, of course.  Otherwise the
126 ** initialization process would never complete.
127 **
128 ** Let X be the first thread to enter this routine.  Let Y be some other
129 ** thread.  Then while the initial invocation of this routine by X is
130 ** incomplete, it is required that:
131 **
132 **    *  Calls to this routine from Y must block until the outer-most
133 **       call by X completes.
134 **
135 **    *  Recursive calls to this routine from thread X return immediately
136 **       without blocking.
137 */
138 int sqlite3_initialize(void){
139   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
140   int rc;                                      /* Result code */
141 #ifdef SQLITE_EXTRA_INIT
142   int bRunExtraInit = 0;                       /* Extra initialization needed */
143 #endif
144 
145 #ifdef SQLITE_OMIT_WSD
146   rc = sqlite3_wsd_init(4096, 24);
147   if( rc!=SQLITE_OK ){
148     return rc;
149   }
150 #endif
151 
152   /* If the following assert() fails on some obscure processor/compiler
153   ** combination, the work-around is to set the correct pointer
154   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
155   assert( SQLITE_PTRSIZE==sizeof(char*) );
156 
157   /* If SQLite is already completely initialized, then this call
158   ** to sqlite3_initialize() should be a no-op.  But the initialization
159   ** must be complete.  So isInit must not be set until the very end
160   ** of this routine.
161   */
162   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
163 
164   /* Make sure the mutex subsystem is initialized.  If unable to
165   ** initialize the mutex subsystem, return early with the error.
166   ** If the system is so sick that we are unable to allocate a mutex,
167   ** there is not much SQLite is going to be able to do.
168   **
169   ** The mutex subsystem must take care of serializing its own
170   ** initialization.
171   */
172   rc = sqlite3MutexInit();
173   if( rc ) return rc;
174 
175   /* Initialize the malloc() system and the recursive pInitMutex mutex.
176   ** This operation is protected by the STATIC_MASTER mutex.  Note that
177   ** MutexAlloc() is called for a static mutex prior to initializing the
178   ** malloc subsystem - this implies that the allocation of a static
179   ** mutex must not require support from the malloc subsystem.
180   */
181   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
182   sqlite3_mutex_enter(pMaster);
183   sqlite3GlobalConfig.isMutexInit = 1;
184   if( !sqlite3GlobalConfig.isMallocInit ){
185     rc = sqlite3MallocInit();
186   }
187   if( rc==SQLITE_OK ){
188     sqlite3GlobalConfig.isMallocInit = 1;
189     if( !sqlite3GlobalConfig.pInitMutex ){
190       sqlite3GlobalConfig.pInitMutex =
191            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
192       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
193         rc = SQLITE_NOMEM_BKPT;
194       }
195     }
196   }
197   if( rc==SQLITE_OK ){
198     sqlite3GlobalConfig.nRefInitMutex++;
199   }
200   sqlite3_mutex_leave(pMaster);
201 
202   /* If rc is not SQLITE_OK at this point, then either the malloc
203   ** subsystem could not be initialized or the system failed to allocate
204   ** the pInitMutex mutex. Return an error in either case.  */
205   if( rc!=SQLITE_OK ){
206     return rc;
207   }
208 
209   /* Do the rest of the initialization under the recursive mutex so
210   ** that we will be able to handle recursive calls into
211   ** sqlite3_initialize().  The recursive calls normally come through
212   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
213   ** recursive calls might also be possible.
214   **
215   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
216   ** to the xInit method, so the xInit method need not be threadsafe.
217   **
218   ** The following mutex is what serializes access to the appdef pcache xInit
219   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
220   ** call to sqlite3PcacheInitialize().
221   */
222   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
223   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
224     sqlite3GlobalConfig.inProgress = 1;
225 #ifdef SQLITE_ENABLE_SQLLOG
226     {
227       extern void sqlite3_init_sqllog(void);
228       sqlite3_init_sqllog();
229     }
230 #endif
231     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
232     sqlite3RegisterBuiltinFunctions();
233     if( sqlite3GlobalConfig.isPCacheInit==0 ){
234       rc = sqlite3PcacheInitialize();
235     }
236     if( rc==SQLITE_OK ){
237       sqlite3GlobalConfig.isPCacheInit = 1;
238       rc = sqlite3OsInit();
239     }
240     if( rc==SQLITE_OK ){
241       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
242           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
243       sqlite3GlobalConfig.isInit = 1;
244 #ifdef SQLITE_EXTRA_INIT
245       bRunExtraInit = 1;
246 #endif
247     }
248     sqlite3GlobalConfig.inProgress = 0;
249   }
250   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
251 
252   /* Go back under the static mutex and clean up the recursive
253   ** mutex to prevent a resource leak.
254   */
255   sqlite3_mutex_enter(pMaster);
256   sqlite3GlobalConfig.nRefInitMutex--;
257   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
258     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
259     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
260     sqlite3GlobalConfig.pInitMutex = 0;
261   }
262   sqlite3_mutex_leave(pMaster);
263 
264   /* The following is just a sanity check to make sure SQLite has
265   ** been compiled correctly.  It is important to run this code, but
266   ** we don't want to run it too often and soak up CPU cycles for no
267   ** reason.  So we run it once during initialization.
268   */
269 #ifndef NDEBUG
270 #ifndef SQLITE_OMIT_FLOATING_POINT
271   /* This section of code's only "output" is via assert() statements. */
272   if ( rc==SQLITE_OK ){
273     u64 x = (((u64)1)<<63)-1;
274     double y;
275     assert(sizeof(x)==8);
276     assert(sizeof(x)==sizeof(y));
277     memcpy(&y, &x, 8);
278     assert( sqlite3IsNaN(y) );
279   }
280 #endif
281 #endif
282 
283   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
284   ** compile-time option.
285   */
286 #ifdef SQLITE_EXTRA_INIT
287   if( bRunExtraInit ){
288     int SQLITE_EXTRA_INIT(const char*);
289     rc = SQLITE_EXTRA_INIT(0);
290   }
291 #endif
292 
293   return rc;
294 }
295 
296 /*
297 ** Undo the effects of sqlite3_initialize().  Must not be called while
298 ** there are outstanding database connections or memory allocations or
299 ** while any part of SQLite is otherwise in use in any thread.  This
300 ** routine is not threadsafe.  But it is safe to invoke this routine
301 ** on when SQLite is already shut down.  If SQLite is already shut down
302 ** when this routine is invoked, then this routine is a harmless no-op.
303 */
304 int sqlite3_shutdown(void){
305 #ifdef SQLITE_OMIT_WSD
306   int rc = sqlite3_wsd_init(4096, 24);
307   if( rc!=SQLITE_OK ){
308     return rc;
309   }
310 #endif
311 
312   if( sqlite3GlobalConfig.isInit ){
313 #ifdef SQLITE_EXTRA_SHUTDOWN
314     void SQLITE_EXTRA_SHUTDOWN(void);
315     SQLITE_EXTRA_SHUTDOWN();
316 #endif
317     sqlite3_os_end();
318     sqlite3_reset_auto_extension();
319     sqlite3GlobalConfig.isInit = 0;
320   }
321   if( sqlite3GlobalConfig.isPCacheInit ){
322     sqlite3PcacheShutdown();
323     sqlite3GlobalConfig.isPCacheInit = 0;
324   }
325   if( sqlite3GlobalConfig.isMallocInit ){
326     sqlite3MallocEnd();
327     sqlite3GlobalConfig.isMallocInit = 0;
328 
329 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
330     /* The heap subsystem has now been shutdown and these values are supposed
331     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
332     ** which would rely on that heap subsystem; therefore, make sure these
333     ** values cannot refer to heap memory that was just invalidated when the
334     ** heap subsystem was shutdown.  This is only done if the current call to
335     ** this function resulted in the heap subsystem actually being shutdown.
336     */
337     sqlite3_data_directory = 0;
338     sqlite3_temp_directory = 0;
339 #endif
340   }
341   if( sqlite3GlobalConfig.isMutexInit ){
342     sqlite3MutexEnd();
343     sqlite3GlobalConfig.isMutexInit = 0;
344   }
345 
346   return SQLITE_OK;
347 }
348 
349 /*
350 ** This API allows applications to modify the global configuration of
351 ** the SQLite library at run-time.
352 **
353 ** This routine should only be called when there are no outstanding
354 ** database connections or memory allocations.  This routine is not
355 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
356 ** behavior.
357 */
358 int sqlite3_config(int op, ...){
359   va_list ap;
360   int rc = SQLITE_OK;
361 
362   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
363   ** the SQLite library is in use. */
364   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
365 
366   va_start(ap, op);
367   switch( op ){
368 
369     /* Mutex configuration options are only available in a threadsafe
370     ** compile.
371     */
372 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
373     case SQLITE_CONFIG_SINGLETHREAD: {
374       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
375       ** Single-thread. */
376       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
377       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
378       break;
379     }
380 #endif
381 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
382     case SQLITE_CONFIG_MULTITHREAD: {
383       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
384       ** Multi-thread. */
385       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
386       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
387       break;
388     }
389 #endif
390 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
391     case SQLITE_CONFIG_SERIALIZED: {
392       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
393       ** Serialized. */
394       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
395       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
396       break;
397     }
398 #endif
399 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
400     case SQLITE_CONFIG_MUTEX: {
401       /* Specify an alternative mutex implementation */
402       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
403       break;
404     }
405 #endif
406 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
407     case SQLITE_CONFIG_GETMUTEX: {
408       /* Retrieve the current mutex implementation */
409       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
410       break;
411     }
412 #endif
413 
414     case SQLITE_CONFIG_MALLOC: {
415       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
416       ** single argument which is a pointer to an instance of the
417       ** sqlite3_mem_methods structure. The argument specifies alternative
418       ** low-level memory allocation routines to be used in place of the memory
419       ** allocation routines built into SQLite. */
420       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
421       break;
422     }
423     case SQLITE_CONFIG_GETMALLOC: {
424       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
425       ** single argument which is a pointer to an instance of the
426       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
427       ** filled with the currently defined memory allocation routines. */
428       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
429       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
430       break;
431     }
432     case SQLITE_CONFIG_MEMSTATUS: {
433       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
434       ** single argument of type int, interpreted as a boolean, which enables
435       ** or disables the collection of memory allocation statistics. */
436       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
437       break;
438     }
439     case SQLITE_CONFIG_SMALL_MALLOC: {
440       sqlite3GlobalConfig.bSmallMalloc = va_arg(ap, int);
441       break;
442     }
443     case SQLITE_CONFIG_PAGECACHE: {
444       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
445       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
446       ** the size of each page cache line (sz), and the number of cache lines
447       ** (N). */
448       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
449       sqlite3GlobalConfig.szPage = va_arg(ap, int);
450       sqlite3GlobalConfig.nPage = va_arg(ap, int);
451       break;
452     }
453     case SQLITE_CONFIG_PCACHE_HDRSZ: {
454       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
455       ** a single parameter which is a pointer to an integer and writes into
456       ** that integer the number of extra bytes per page required for each page
457       ** in SQLITE_CONFIG_PAGECACHE. */
458       *va_arg(ap, int*) =
459           sqlite3HeaderSizeBtree() +
460           sqlite3HeaderSizePcache() +
461           sqlite3HeaderSizePcache1();
462       break;
463     }
464 
465     case SQLITE_CONFIG_PCACHE: {
466       /* no-op */
467       break;
468     }
469     case SQLITE_CONFIG_GETPCACHE: {
470       /* now an error */
471       rc = SQLITE_ERROR;
472       break;
473     }
474 
475     case SQLITE_CONFIG_PCACHE2: {
476       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
477       ** single argument which is a pointer to an sqlite3_pcache_methods2
478       ** object. This object specifies the interface to a custom page cache
479       ** implementation. */
480       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
481       break;
482     }
483     case SQLITE_CONFIG_GETPCACHE2: {
484       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
485       ** single argument which is a pointer to an sqlite3_pcache_methods2
486       ** object. SQLite copies of the current page cache implementation into
487       ** that object. */
488       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
489         sqlite3PCacheSetDefault();
490       }
491       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
492       break;
493     }
494 
495 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
496 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
497 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
498 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
499     case SQLITE_CONFIG_HEAP: {
500       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
501       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
502       ** number of bytes in the memory buffer, and the minimum allocation size.
503       */
504       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
505       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
506       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
507 
508       if( sqlite3GlobalConfig.mnReq<1 ){
509         sqlite3GlobalConfig.mnReq = 1;
510       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
511         /* cap min request size at 2^12 */
512         sqlite3GlobalConfig.mnReq = (1<<12);
513       }
514 
515       if( sqlite3GlobalConfig.pHeap==0 ){
516         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
517         ** is NULL, then SQLite reverts to using its default memory allocator
518         ** (the system malloc() implementation), undoing any prior invocation of
519         ** SQLITE_CONFIG_MALLOC.
520         **
521         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
522         ** revert to its default implementation when sqlite3_initialize() is run
523         */
524         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
525       }else{
526         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
527         ** alternative memory allocator is engaged to handle all of SQLites
528         ** memory allocation needs. */
529 #ifdef SQLITE_ENABLE_MEMSYS3
530         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
531 #endif
532 #ifdef SQLITE_ENABLE_MEMSYS5
533         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
534 #endif
535       }
536       break;
537     }
538 #endif
539 
540     case SQLITE_CONFIG_LOOKASIDE: {
541       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
542       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
543       break;
544     }
545 
546     /* Record a pointer to the logger function and its first argument.
547     ** The default is NULL.  Logging is disabled if the function pointer is
548     ** NULL.
549     */
550     case SQLITE_CONFIG_LOG: {
551       /* MSVC is picky about pulling func ptrs from va lists.
552       ** http://support.microsoft.com/kb/47961
553       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
554       */
555       typedef void(*LOGFUNC_t)(void*,int,const char*);
556       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
557       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
558       break;
559     }
560 
561     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
562     ** can be changed at start-time using the
563     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
564     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
565     */
566     case SQLITE_CONFIG_URI: {
567       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
568       ** argument of type int. If non-zero, then URI handling is globally
569       ** enabled. If the parameter is zero, then URI handling is globally
570       ** disabled. */
571       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
572       break;
573     }
574 
575     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
576       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
577       ** option takes a single integer argument which is interpreted as a
578       ** boolean in order to enable or disable the use of covering indices for
579       ** full table scans in the query optimizer. */
580       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
581       break;
582     }
583 
584 #ifdef SQLITE_ENABLE_SQLLOG
585     case SQLITE_CONFIG_SQLLOG: {
586       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
587       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
588       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
589       break;
590     }
591 #endif
592 
593     case SQLITE_CONFIG_MMAP_SIZE: {
594       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
595       ** integer (sqlite3_int64) values that are the default mmap size limit
596       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
597       ** mmap size limit. */
598       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
599       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
600       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
601       ** negative, then that argument is changed to its compile-time default.
602       **
603       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
604       ** silently truncated if necessary so that it does not exceed the
605       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
606       ** compile-time option.
607       */
608       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
609         mxMmap = SQLITE_MAX_MMAP_SIZE;
610       }
611       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
612       if( szMmap>mxMmap) szMmap = mxMmap;
613       sqlite3GlobalConfig.mxMmap = mxMmap;
614       sqlite3GlobalConfig.szMmap = szMmap;
615       break;
616     }
617 
618 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
619     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
620       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
621       ** unsigned integer value that specifies the maximum size of the created
622       ** heap. */
623       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
624       break;
625     }
626 #endif
627 
628     case SQLITE_CONFIG_PMASZ: {
629       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
630       break;
631     }
632 
633     case SQLITE_CONFIG_STMTJRNL_SPILL: {
634       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
635       break;
636     }
637 
638     default: {
639       rc = SQLITE_ERROR;
640       break;
641     }
642   }
643   va_end(ap);
644   return rc;
645 }
646 
647 /*
648 ** Set up the lookaside buffers for a database connection.
649 ** Return SQLITE_OK on success.
650 ** If lookaside is already active, return SQLITE_BUSY.
651 **
652 ** The sz parameter is the number of bytes in each lookaside slot.
653 ** The cnt parameter is the number of slots.  If pStart is NULL the
654 ** space for the lookaside memory is obtained from sqlite3_malloc().
655 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
656 ** the lookaside memory.
657 */
658 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
659 #ifndef SQLITE_OMIT_LOOKASIDE
660   void *pStart;
661 
662   if( sqlite3LookasideUsed(db,0)>0 ){
663     return SQLITE_BUSY;
664   }
665   /* Free any existing lookaside buffer for this handle before
666   ** allocating a new one so we don't have to have space for
667   ** both at the same time.
668   */
669   if( db->lookaside.bMalloced ){
670     sqlite3_free(db->lookaside.pStart);
671   }
672   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
673   ** than a pointer to be useful.
674   */
675   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
676   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
677   if( cnt<0 ) cnt = 0;
678   if( sz==0 || cnt==0 ){
679     sz = 0;
680     pStart = 0;
681   }else if( pBuf==0 ){
682     sqlite3BeginBenignMalloc();
683     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
684     sqlite3EndBenignMalloc();
685     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
686   }else{
687     pStart = pBuf;
688   }
689   db->lookaside.pStart = pStart;
690   db->lookaside.pInit = 0;
691   db->lookaside.pFree = 0;
692   db->lookaside.sz = (u16)sz;
693   if( pStart ){
694     int i;
695     LookasideSlot *p;
696     assert( sz > (int)sizeof(LookasideSlot*) );
697     db->lookaside.nSlot = cnt;
698     p = (LookasideSlot*)pStart;
699     for(i=cnt-1; i>=0; i--){
700       p->pNext = db->lookaside.pInit;
701       db->lookaside.pInit = p;
702       p = (LookasideSlot*)&((u8*)p)[sz];
703     }
704     db->lookaside.pEnd = p;
705     db->lookaside.bDisable = 0;
706     db->lookaside.bMalloced = pBuf==0 ?1:0;
707   }else{
708     db->lookaside.pStart = db;
709     db->lookaside.pEnd = db;
710     db->lookaside.bDisable = 1;
711     db->lookaside.bMalloced = 0;
712     db->lookaside.nSlot = 0;
713   }
714 #endif /* SQLITE_OMIT_LOOKASIDE */
715   return SQLITE_OK;
716 }
717 
718 /*
719 ** Return the mutex associated with a database connection.
720 */
721 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
722 #ifdef SQLITE_ENABLE_API_ARMOR
723   if( !sqlite3SafetyCheckOk(db) ){
724     (void)SQLITE_MISUSE_BKPT;
725     return 0;
726   }
727 #endif
728   return db->mutex;
729 }
730 
731 /*
732 ** Free up as much memory as we can from the given database
733 ** connection.
734 */
735 int sqlite3_db_release_memory(sqlite3 *db){
736   int i;
737 
738 #ifdef SQLITE_ENABLE_API_ARMOR
739   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
740 #endif
741   sqlite3_mutex_enter(db->mutex);
742   sqlite3BtreeEnterAll(db);
743   for(i=0; i<db->nDb; i++){
744     Btree *pBt = db->aDb[i].pBt;
745     if( pBt ){
746       Pager *pPager = sqlite3BtreePager(pBt);
747       sqlite3PagerShrink(pPager);
748     }
749   }
750   sqlite3BtreeLeaveAll(db);
751   sqlite3_mutex_leave(db->mutex);
752   return SQLITE_OK;
753 }
754 
755 /*
756 ** Flush any dirty pages in the pager-cache for any attached database
757 ** to disk.
758 */
759 int sqlite3_db_cacheflush(sqlite3 *db){
760   int i;
761   int rc = SQLITE_OK;
762   int bSeenBusy = 0;
763 
764 #ifdef SQLITE_ENABLE_API_ARMOR
765   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
766 #endif
767   sqlite3_mutex_enter(db->mutex);
768   sqlite3BtreeEnterAll(db);
769   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
770     Btree *pBt = db->aDb[i].pBt;
771     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
772       Pager *pPager = sqlite3BtreePager(pBt);
773       rc = sqlite3PagerFlush(pPager);
774       if( rc==SQLITE_BUSY ){
775         bSeenBusy = 1;
776         rc = SQLITE_OK;
777       }
778     }
779   }
780   sqlite3BtreeLeaveAll(db);
781   sqlite3_mutex_leave(db->mutex);
782   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
783 }
784 
785 /*
786 ** Configuration settings for an individual database connection
787 */
788 int sqlite3_db_config(sqlite3 *db, int op, ...){
789   va_list ap;
790   int rc;
791   va_start(ap, op);
792   switch( op ){
793     case SQLITE_DBCONFIG_MAINDBNAME: {
794       /* IMP: R-06824-28531 */
795       /* IMP: R-36257-52125 */
796       db->aDb[0].zDbSName = va_arg(ap,char*);
797       rc = SQLITE_OK;
798       break;
799     }
800     case SQLITE_DBCONFIG_LOOKASIDE: {
801       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
802       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
803       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
804       rc = setupLookaside(db, pBuf, sz, cnt);
805       break;
806     }
807     default: {
808       static const struct {
809         int op;      /* The opcode */
810         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
811       } aFlagOp[] = {
812         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
813         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
814         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
815         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
816         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
817         { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
818       };
819       unsigned int i;
820       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
821       for(i=0; i<ArraySize(aFlagOp); i++){
822         if( aFlagOp[i].op==op ){
823           int onoff = va_arg(ap, int);
824           int *pRes = va_arg(ap, int*);
825           u32 oldFlags = db->flags;
826           if( onoff>0 ){
827             db->flags |= aFlagOp[i].mask;
828           }else if( onoff==0 ){
829             db->flags &= ~aFlagOp[i].mask;
830           }
831           if( oldFlags!=db->flags ){
832             sqlite3ExpirePreparedStatements(db);
833           }
834           if( pRes ){
835             *pRes = (db->flags & aFlagOp[i].mask)!=0;
836           }
837           rc = SQLITE_OK;
838           break;
839         }
840       }
841       break;
842     }
843   }
844   va_end(ap);
845   return rc;
846 }
847 
848 
849 /*
850 ** Return true if the buffer z[0..n-1] contains all spaces.
851 */
852 static int allSpaces(const char *z, int n){
853   while( n>0 && z[n-1]==' ' ){ n--; }
854   return n==0;
855 }
856 
857 /*
858 ** This is the default collating function named "BINARY" which is always
859 ** available.
860 **
861 ** If the padFlag argument is not NULL then space padding at the end
862 ** of strings is ignored.  This implements the RTRIM collation.
863 */
864 static int binCollFunc(
865   void *padFlag,
866   int nKey1, const void *pKey1,
867   int nKey2, const void *pKey2
868 ){
869   int rc, n;
870   n = nKey1<nKey2 ? nKey1 : nKey2;
871   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
872   ** strings byte by byte using the memcmp() function from the standard C
873   ** library. */
874   assert( pKey1 && pKey2 );
875   rc = memcmp(pKey1, pKey2, n);
876   if( rc==0 ){
877     if( padFlag
878      && allSpaces(((char*)pKey1)+n, nKey1-n)
879      && allSpaces(((char*)pKey2)+n, nKey2-n)
880     ){
881       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
882       ** spaces at the end of either string do not change the result. In other
883       ** words, strings will compare equal to one another as long as they
884       ** differ only in the number of spaces at the end.
885       */
886     }else{
887       rc = nKey1 - nKey2;
888     }
889   }
890   return rc;
891 }
892 
893 /*
894 ** Another built-in collating sequence: NOCASE.
895 **
896 ** This collating sequence is intended to be used for "case independent
897 ** comparison". SQLite's knowledge of upper and lower case equivalents
898 ** extends only to the 26 characters used in the English language.
899 **
900 ** At the moment there is only a UTF-8 implementation.
901 */
902 static int nocaseCollatingFunc(
903   void *NotUsed,
904   int nKey1, const void *pKey1,
905   int nKey2, const void *pKey2
906 ){
907   int r = sqlite3StrNICmp(
908       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
909   UNUSED_PARAMETER(NotUsed);
910   if( 0==r ){
911     r = nKey1-nKey2;
912   }
913   return r;
914 }
915 
916 /*
917 ** Return the ROWID of the most recent insert
918 */
919 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
920 #ifdef SQLITE_ENABLE_API_ARMOR
921   if( !sqlite3SafetyCheckOk(db) ){
922     (void)SQLITE_MISUSE_BKPT;
923     return 0;
924   }
925 #endif
926   return db->lastRowid;
927 }
928 
929 /*
930 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
931 */
932 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
933 #ifdef SQLITE_ENABLE_API_ARMOR
934   if( !sqlite3SafetyCheckOk(db) ){
935     (void)SQLITE_MISUSE_BKPT;
936     return;
937   }
938 #endif
939   sqlite3_mutex_enter(db->mutex);
940   db->lastRowid = iRowid;
941   sqlite3_mutex_leave(db->mutex);
942 }
943 
944 /*
945 ** Return the number of changes in the most recent call to sqlite3_exec().
946 */
947 int sqlite3_changes(sqlite3 *db){
948 #ifdef SQLITE_ENABLE_API_ARMOR
949   if( !sqlite3SafetyCheckOk(db) ){
950     (void)SQLITE_MISUSE_BKPT;
951     return 0;
952   }
953 #endif
954   return db->nChange;
955 }
956 
957 /*
958 ** Return the number of changes since the database handle was opened.
959 */
960 int sqlite3_total_changes(sqlite3 *db){
961 #ifdef SQLITE_ENABLE_API_ARMOR
962   if( !sqlite3SafetyCheckOk(db) ){
963     (void)SQLITE_MISUSE_BKPT;
964     return 0;
965   }
966 #endif
967   return db->nTotalChange;
968 }
969 
970 /*
971 ** Close all open savepoints. This function only manipulates fields of the
972 ** database handle object, it does not close any savepoints that may be open
973 ** at the b-tree/pager level.
974 */
975 void sqlite3CloseSavepoints(sqlite3 *db){
976   while( db->pSavepoint ){
977     Savepoint *pTmp = db->pSavepoint;
978     db->pSavepoint = pTmp->pNext;
979     sqlite3DbFree(db, pTmp);
980   }
981   db->nSavepoint = 0;
982   db->nStatement = 0;
983   db->isTransactionSavepoint = 0;
984 }
985 
986 /*
987 ** Invoke the destructor function associated with FuncDef p, if any. Except,
988 ** if this is not the last copy of the function, do not invoke it. Multiple
989 ** copies of a single function are created when create_function() is called
990 ** with SQLITE_ANY as the encoding.
991 */
992 static void functionDestroy(sqlite3 *db, FuncDef *p){
993   FuncDestructor *pDestructor = p->u.pDestructor;
994   if( pDestructor ){
995     pDestructor->nRef--;
996     if( pDestructor->nRef==0 ){
997       pDestructor->xDestroy(pDestructor->pUserData);
998       sqlite3DbFree(db, pDestructor);
999     }
1000   }
1001 }
1002 
1003 /*
1004 ** Disconnect all sqlite3_vtab objects that belong to database connection
1005 ** db. This is called when db is being closed.
1006 */
1007 static void disconnectAllVtab(sqlite3 *db){
1008 #ifndef SQLITE_OMIT_VIRTUALTABLE
1009   int i;
1010   HashElem *p;
1011   sqlite3BtreeEnterAll(db);
1012   for(i=0; i<db->nDb; i++){
1013     Schema *pSchema = db->aDb[i].pSchema;
1014     if( db->aDb[i].pSchema ){
1015       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1016         Table *pTab = (Table *)sqliteHashData(p);
1017         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1018       }
1019     }
1020   }
1021   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1022     Module *pMod = (Module *)sqliteHashData(p);
1023     if( pMod->pEpoTab ){
1024       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1025     }
1026   }
1027   sqlite3VtabUnlockList(db);
1028   sqlite3BtreeLeaveAll(db);
1029 #else
1030   UNUSED_PARAMETER(db);
1031 #endif
1032 }
1033 
1034 /*
1035 ** Return TRUE if database connection db has unfinalized prepared
1036 ** statements or unfinished sqlite3_backup objects.
1037 */
1038 static int connectionIsBusy(sqlite3 *db){
1039   int j;
1040   assert( sqlite3_mutex_held(db->mutex) );
1041   if( db->pVdbe ) return 1;
1042   for(j=0; j<db->nDb; j++){
1043     Btree *pBt = db->aDb[j].pBt;
1044     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1045   }
1046   return 0;
1047 }
1048 
1049 /*
1050 ** Close an existing SQLite database
1051 */
1052 static int sqlite3Close(sqlite3 *db, int forceZombie){
1053   if( !db ){
1054     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1055     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1056     return SQLITE_OK;
1057   }
1058   if( !sqlite3SafetyCheckSickOrOk(db) ){
1059     return SQLITE_MISUSE_BKPT;
1060   }
1061   sqlite3_mutex_enter(db->mutex);
1062   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1063     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1064   }
1065 
1066   /* Force xDisconnect calls on all virtual tables */
1067   disconnectAllVtab(db);
1068 
1069   /* If a transaction is open, the disconnectAllVtab() call above
1070   ** will not have called the xDisconnect() method on any virtual
1071   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1072   ** call will do so. We need to do this before the check for active
1073   ** SQL statements below, as the v-table implementation may be storing
1074   ** some prepared statements internally.
1075   */
1076   sqlite3VtabRollback(db);
1077 
1078   /* Legacy behavior (sqlite3_close() behavior) is to return
1079   ** SQLITE_BUSY if the connection can not be closed immediately.
1080   */
1081   if( !forceZombie && connectionIsBusy(db) ){
1082     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1083        "statements or unfinished backups");
1084     sqlite3_mutex_leave(db->mutex);
1085     return SQLITE_BUSY;
1086   }
1087 
1088 #ifdef SQLITE_ENABLE_SQLLOG
1089   if( sqlite3GlobalConfig.xSqllog ){
1090     /* Closing the handle. Fourth parameter is passed the value 2. */
1091     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1092   }
1093 #endif
1094 
1095   /* Convert the connection into a zombie and then close it.
1096   */
1097   db->magic = SQLITE_MAGIC_ZOMBIE;
1098   sqlite3LeaveMutexAndCloseZombie(db);
1099   return SQLITE_OK;
1100 }
1101 
1102 /*
1103 ** Two variations on the public interface for closing a database
1104 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1105 ** leaves the connection option if there are unfinalized prepared
1106 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1107 ** version forces the connection to become a zombie if there are
1108 ** unclosed resources, and arranges for deallocation when the last
1109 ** prepare statement or sqlite3_backup closes.
1110 */
1111 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1112 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1113 
1114 
1115 /*
1116 ** Close the mutex on database connection db.
1117 **
1118 ** Furthermore, if database connection db is a zombie (meaning that there
1119 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1120 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1121 ** finished, then free all resources.
1122 */
1123 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1124   HashElem *i;                    /* Hash table iterator */
1125   int j;
1126 
1127   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1128   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1129   ** then just leave the mutex and return.
1130   */
1131   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1132     sqlite3_mutex_leave(db->mutex);
1133     return;
1134   }
1135 
1136   /* If we reach this point, it means that the database connection has
1137   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1138   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1139   ** go ahead and free all resources.
1140   */
1141 
1142   /* If a transaction is open, roll it back. This also ensures that if
1143   ** any database schemas have been modified by an uncommitted transaction
1144   ** they are reset. And that the required b-tree mutex is held to make
1145   ** the pager rollback and schema reset an atomic operation. */
1146   sqlite3RollbackAll(db, SQLITE_OK);
1147 
1148   /* Free any outstanding Savepoint structures. */
1149   sqlite3CloseSavepoints(db);
1150 
1151   /* Close all database connections */
1152   for(j=0; j<db->nDb; j++){
1153     struct Db *pDb = &db->aDb[j];
1154     if( pDb->pBt ){
1155       sqlite3BtreeClose(pDb->pBt);
1156       pDb->pBt = 0;
1157       if( j!=1 ){
1158         pDb->pSchema = 0;
1159       }
1160     }
1161   }
1162   /* Clear the TEMP schema separately and last */
1163   if( db->aDb[1].pSchema ){
1164     sqlite3SchemaClear(db->aDb[1].pSchema);
1165   }
1166   sqlite3VtabUnlockList(db);
1167 
1168   /* Free up the array of auxiliary databases */
1169   sqlite3CollapseDatabaseArray(db);
1170   assert( db->nDb<=2 );
1171   assert( db->aDb==db->aDbStatic );
1172 
1173   /* Tell the code in notify.c that the connection no longer holds any
1174   ** locks and does not require any further unlock-notify callbacks.
1175   */
1176   sqlite3ConnectionClosed(db);
1177 
1178   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1179     FuncDef *pNext, *p;
1180     p = sqliteHashData(i);
1181     do{
1182       functionDestroy(db, p);
1183       pNext = p->pNext;
1184       sqlite3DbFree(db, p);
1185       p = pNext;
1186     }while( p );
1187   }
1188   sqlite3HashClear(&db->aFunc);
1189   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1190     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1191     /* Invoke any destructors registered for collation sequence user data. */
1192     for(j=0; j<3; j++){
1193       if( pColl[j].xDel ){
1194         pColl[j].xDel(pColl[j].pUser);
1195       }
1196     }
1197     sqlite3DbFree(db, pColl);
1198   }
1199   sqlite3HashClear(&db->aCollSeq);
1200 #ifndef SQLITE_OMIT_VIRTUALTABLE
1201   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1202     Module *pMod = (Module *)sqliteHashData(i);
1203     if( pMod->xDestroy ){
1204       pMod->xDestroy(pMod->pAux);
1205     }
1206     sqlite3VtabEponymousTableClear(db, pMod);
1207     sqlite3DbFree(db, pMod);
1208   }
1209   sqlite3HashClear(&db->aModule);
1210 #endif
1211 
1212   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1213   sqlite3ValueFree(db->pErr);
1214   sqlite3CloseExtensions(db);
1215 #if SQLITE_USER_AUTHENTICATION
1216   sqlite3_free(db->auth.zAuthUser);
1217   sqlite3_free(db->auth.zAuthPW);
1218 #endif
1219 
1220   db->magic = SQLITE_MAGIC_ERROR;
1221 
1222   /* The temp-database schema is allocated differently from the other schema
1223   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1224   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1225   ** the same sqliteMalloc() as the one that allocates the database
1226   ** structure?
1227   */
1228   sqlite3DbFree(db, db->aDb[1].pSchema);
1229   sqlite3_mutex_leave(db->mutex);
1230   db->magic = SQLITE_MAGIC_CLOSED;
1231   sqlite3_mutex_free(db->mutex);
1232   assert( sqlite3LookasideUsed(db,0)==0 );
1233   if( db->lookaside.bMalloced ){
1234     sqlite3_free(db->lookaside.pStart);
1235   }
1236   sqlite3_free(db);
1237 }
1238 
1239 /*
1240 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1241 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1242 ** breaker") and made to return tripCode if there are any further
1243 ** attempts to use that cursor.  Read cursors remain open and valid
1244 ** but are "saved" in case the table pages are moved around.
1245 */
1246 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1247   int i;
1248   int inTrans = 0;
1249   int schemaChange;
1250   assert( sqlite3_mutex_held(db->mutex) );
1251   sqlite3BeginBenignMalloc();
1252 
1253   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1254   ** This is important in case the transaction being rolled back has
1255   ** modified the database schema. If the b-tree mutexes are not taken
1256   ** here, then another shared-cache connection might sneak in between
1257   ** the database rollback and schema reset, which can cause false
1258   ** corruption reports in some cases.  */
1259   sqlite3BtreeEnterAll(db);
1260   schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
1261 
1262   for(i=0; i<db->nDb; i++){
1263     Btree *p = db->aDb[i].pBt;
1264     if( p ){
1265       if( sqlite3BtreeIsInTrans(p) ){
1266         inTrans = 1;
1267       }
1268       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1269     }
1270   }
1271   sqlite3VtabRollback(db);
1272   sqlite3EndBenignMalloc();
1273 
1274   if( (db->mDbFlags&DBFLAG_SchemaChange)!=0 && db->init.busy==0 ){
1275     sqlite3ExpirePreparedStatements(db);
1276     sqlite3ResetAllSchemasOfConnection(db);
1277   }
1278   sqlite3BtreeLeaveAll(db);
1279 
1280   /* Any deferred constraint violations have now been resolved. */
1281   db->nDeferredCons = 0;
1282   db->nDeferredImmCons = 0;
1283   db->flags &= ~SQLITE_DeferFKs;
1284 
1285   /* If one has been configured, invoke the rollback-hook callback */
1286   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1287     db->xRollbackCallback(db->pRollbackArg);
1288   }
1289 }
1290 
1291 /*
1292 ** Return a static string containing the name corresponding to the error code
1293 ** specified in the argument.
1294 */
1295 #if defined(SQLITE_NEED_ERR_NAME)
1296 const char *sqlite3ErrName(int rc){
1297   const char *zName = 0;
1298   int i, origRc = rc;
1299   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1300     switch( rc ){
1301       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1302       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1303       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1304       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1305       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1306       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1307       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1308       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1309       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1310       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1311       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1312       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1313       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1314       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1315       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1316       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1317       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1318       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1319       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1320       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1321       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1322       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1323       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1324       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1325       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1326       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1327       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1328       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1329       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1330       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1331       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1332       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1333                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1334       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1335       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1336       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1337       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1338       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1339       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1340       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1341       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1342       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1343       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1344       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1345       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1346       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1347       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1348       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1349       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1350       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1351       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1352       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1353       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1354       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1355       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1356       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1357       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1358       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1359       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1360       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1361       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1362       case SQLITE_CONSTRAINT_FOREIGNKEY:
1363                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1364       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1365       case SQLITE_CONSTRAINT_PRIMARYKEY:
1366                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1367       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1368       case SQLITE_CONSTRAINT_COMMITHOOK:
1369                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1370       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1371       case SQLITE_CONSTRAINT_FUNCTION:
1372                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1373       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1374       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1375       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1376       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1377       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1378       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1379       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1380       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1381       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1382       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1383       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1384       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1385                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1386       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1387       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1388       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1389     }
1390   }
1391   if( zName==0 ){
1392     static char zBuf[50];
1393     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1394     zName = zBuf;
1395   }
1396   return zName;
1397 }
1398 #endif
1399 
1400 /*
1401 ** Return a static string that describes the kind of error specified in the
1402 ** argument.
1403 */
1404 const char *sqlite3ErrStr(int rc){
1405   static const char* const aMsg[] = {
1406     /* SQLITE_OK          */ "not an error",
1407     /* SQLITE_ERROR       */ "SQL logic error",
1408     /* SQLITE_INTERNAL    */ 0,
1409     /* SQLITE_PERM        */ "access permission denied",
1410     /* SQLITE_ABORT       */ "query aborted",
1411     /* SQLITE_BUSY        */ "database is locked",
1412     /* SQLITE_LOCKED      */ "database table is locked",
1413     /* SQLITE_NOMEM       */ "out of memory",
1414     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1415     /* SQLITE_INTERRUPT   */ "interrupted",
1416     /* SQLITE_IOERR       */ "disk I/O error",
1417     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1418     /* SQLITE_NOTFOUND    */ "unknown operation",
1419     /* SQLITE_FULL        */ "database or disk is full",
1420     /* SQLITE_CANTOPEN    */ "unable to open database file",
1421     /* SQLITE_PROTOCOL    */ "locking protocol",
1422     /* SQLITE_EMPTY       */ 0,
1423     /* SQLITE_SCHEMA      */ "database schema has changed",
1424     /* SQLITE_TOOBIG      */ "string or blob too big",
1425     /* SQLITE_CONSTRAINT  */ "constraint failed",
1426     /* SQLITE_MISMATCH    */ "datatype mismatch",
1427     /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
1428 #ifdef SQLITE_DISABLE_LFS
1429     /* SQLITE_NOLFS       */ "large file support is disabled",
1430 #else
1431     /* SQLITE_NOLFS       */ 0,
1432 #endif
1433     /* SQLITE_AUTH        */ "authorization denied",
1434     /* SQLITE_FORMAT      */ 0,
1435     /* SQLITE_RANGE       */ "column index out of range",
1436     /* SQLITE_NOTADB      */ "file is not a database",
1437   };
1438   const char *zErr = "unknown error";
1439   switch( rc ){
1440     case SQLITE_ABORT_ROLLBACK: {
1441       zErr = "abort due to ROLLBACK";
1442       break;
1443     }
1444     default: {
1445       rc &= 0xff;
1446       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1447         zErr = aMsg[rc];
1448       }
1449       break;
1450     }
1451   }
1452   return zErr;
1453 }
1454 
1455 /*
1456 ** This routine implements a busy callback that sleeps and tries
1457 ** again until a timeout value is reached.  The timeout value is
1458 ** an integer number of milliseconds passed in as the first
1459 ** argument.
1460 */
1461 static int sqliteDefaultBusyCallback(
1462  void *ptr,               /* Database connection */
1463  int count                /* Number of times table has been busy */
1464 ){
1465 #if SQLITE_OS_WIN || HAVE_USLEEP
1466   static const u8 delays[] =
1467      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1468   static const u8 totals[] =
1469      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1470 # define NDELAY ArraySize(delays)
1471   sqlite3 *db = (sqlite3 *)ptr;
1472   int timeout = db->busyTimeout;
1473   int delay, prior;
1474 
1475   assert( count>=0 );
1476   if( count < NDELAY ){
1477     delay = delays[count];
1478     prior = totals[count];
1479   }else{
1480     delay = delays[NDELAY-1];
1481     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1482   }
1483   if( prior + delay > timeout ){
1484     delay = timeout - prior;
1485     if( delay<=0 ) return 0;
1486   }
1487   sqlite3OsSleep(db->pVfs, delay*1000);
1488   return 1;
1489 #else
1490   sqlite3 *db = (sqlite3 *)ptr;
1491   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1492   if( (count+1)*1000 > timeout ){
1493     return 0;
1494   }
1495   sqlite3OsSleep(db->pVfs, 1000000);
1496   return 1;
1497 #endif
1498 }
1499 
1500 /*
1501 ** Invoke the given busy handler.
1502 **
1503 ** This routine is called when an operation failed with a lock.
1504 ** If this routine returns non-zero, the lock is retried.  If it
1505 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1506 */
1507 int sqlite3InvokeBusyHandler(BusyHandler *p){
1508   int rc;
1509   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1510   rc = p->xFunc(p->pArg, p->nBusy);
1511   if( rc==0 ){
1512     p->nBusy = -1;
1513   }else{
1514     p->nBusy++;
1515   }
1516   return rc;
1517 }
1518 
1519 /*
1520 ** This routine sets the busy callback for an Sqlite database to the
1521 ** given callback function with the given argument.
1522 */
1523 int sqlite3_busy_handler(
1524   sqlite3 *db,
1525   int (*xBusy)(void*,int),
1526   void *pArg
1527 ){
1528 #ifdef SQLITE_ENABLE_API_ARMOR
1529   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1530 #endif
1531   sqlite3_mutex_enter(db->mutex);
1532   db->busyHandler.xFunc = xBusy;
1533   db->busyHandler.pArg = pArg;
1534   db->busyHandler.nBusy = 0;
1535   db->busyTimeout = 0;
1536   sqlite3_mutex_leave(db->mutex);
1537   return SQLITE_OK;
1538 }
1539 
1540 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1541 /*
1542 ** This routine sets the progress callback for an Sqlite database to the
1543 ** given callback function with the given argument. The progress callback will
1544 ** be invoked every nOps opcodes.
1545 */
1546 void sqlite3_progress_handler(
1547   sqlite3 *db,
1548   int nOps,
1549   int (*xProgress)(void*),
1550   void *pArg
1551 ){
1552 #ifdef SQLITE_ENABLE_API_ARMOR
1553   if( !sqlite3SafetyCheckOk(db) ){
1554     (void)SQLITE_MISUSE_BKPT;
1555     return;
1556   }
1557 #endif
1558   sqlite3_mutex_enter(db->mutex);
1559   if( nOps>0 ){
1560     db->xProgress = xProgress;
1561     db->nProgressOps = (unsigned)nOps;
1562     db->pProgressArg = pArg;
1563   }else{
1564     db->xProgress = 0;
1565     db->nProgressOps = 0;
1566     db->pProgressArg = 0;
1567   }
1568   sqlite3_mutex_leave(db->mutex);
1569 }
1570 #endif
1571 
1572 
1573 /*
1574 ** This routine installs a default busy handler that waits for the
1575 ** specified number of milliseconds before returning 0.
1576 */
1577 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1578 #ifdef SQLITE_ENABLE_API_ARMOR
1579   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1580 #endif
1581   if( ms>0 ){
1582     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1583     db->busyTimeout = ms;
1584   }else{
1585     sqlite3_busy_handler(db, 0, 0);
1586   }
1587   return SQLITE_OK;
1588 }
1589 
1590 /*
1591 ** Cause any pending operation to stop at its earliest opportunity.
1592 */
1593 void sqlite3_interrupt(sqlite3 *db){
1594 #ifdef SQLITE_ENABLE_API_ARMOR
1595   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1596     (void)SQLITE_MISUSE_BKPT;
1597     return;
1598   }
1599 #endif
1600   db->u1.isInterrupted = 1;
1601 }
1602 
1603 
1604 /*
1605 ** This function is exactly the same as sqlite3_create_function(), except
1606 ** that it is designed to be called by internal code. The difference is
1607 ** that if a malloc() fails in sqlite3_create_function(), an error code
1608 ** is returned and the mallocFailed flag cleared.
1609 */
1610 int sqlite3CreateFunc(
1611   sqlite3 *db,
1612   const char *zFunctionName,
1613   int nArg,
1614   int enc,
1615   void *pUserData,
1616   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1617   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1618   void (*xFinal)(sqlite3_context*),
1619   FuncDestructor *pDestructor
1620 ){
1621   FuncDef *p;
1622   int nName;
1623   int extraFlags;
1624 
1625   assert( sqlite3_mutex_held(db->mutex) );
1626   if( zFunctionName==0 ||
1627       (xSFunc && (xFinal || xStep)) ||
1628       (!xSFunc && (xFinal && !xStep)) ||
1629       (!xSFunc && (!xFinal && xStep)) ||
1630       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1631       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1632     return SQLITE_MISUSE_BKPT;
1633   }
1634 
1635   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1636   extraFlags = enc &  SQLITE_DETERMINISTIC;
1637   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1638 
1639 #ifndef SQLITE_OMIT_UTF16
1640   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1641   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1642   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1643   **
1644   ** If SQLITE_ANY is specified, add three versions of the function
1645   ** to the hash table.
1646   */
1647   if( enc==SQLITE_UTF16 ){
1648     enc = SQLITE_UTF16NATIVE;
1649   }else if( enc==SQLITE_ANY ){
1650     int rc;
1651     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1652          pUserData, xSFunc, xStep, xFinal, pDestructor);
1653     if( rc==SQLITE_OK ){
1654       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1655           pUserData, xSFunc, xStep, xFinal, pDestructor);
1656     }
1657     if( rc!=SQLITE_OK ){
1658       return rc;
1659     }
1660     enc = SQLITE_UTF16BE;
1661   }
1662 #else
1663   enc = SQLITE_UTF8;
1664 #endif
1665 
1666   /* Check if an existing function is being overridden or deleted. If so,
1667   ** and there are active VMs, then return SQLITE_BUSY. If a function
1668   ** is being overridden/deleted but there are no active VMs, allow the
1669   ** operation to continue but invalidate all precompiled statements.
1670   */
1671   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1672   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1673     if( db->nVdbeActive ){
1674       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1675         "unable to delete/modify user-function due to active statements");
1676       assert( !db->mallocFailed );
1677       return SQLITE_BUSY;
1678     }else{
1679       sqlite3ExpirePreparedStatements(db);
1680     }
1681   }
1682 
1683   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1684   assert(p || db->mallocFailed);
1685   if( !p ){
1686     return SQLITE_NOMEM_BKPT;
1687   }
1688 
1689   /* If an older version of the function with a configured destructor is
1690   ** being replaced invoke the destructor function here. */
1691   functionDestroy(db, p);
1692 
1693   if( pDestructor ){
1694     pDestructor->nRef++;
1695   }
1696   p->u.pDestructor = pDestructor;
1697   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1698   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1699   p->xSFunc = xSFunc ? xSFunc : xStep;
1700   p->xFinalize = xFinal;
1701   p->pUserData = pUserData;
1702   p->nArg = (u16)nArg;
1703   return SQLITE_OK;
1704 }
1705 
1706 /*
1707 ** Create new user functions.
1708 */
1709 int sqlite3_create_function(
1710   sqlite3 *db,
1711   const char *zFunc,
1712   int nArg,
1713   int enc,
1714   void *p,
1715   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1716   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1717   void (*xFinal)(sqlite3_context*)
1718 ){
1719   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1720                                     xFinal, 0);
1721 }
1722 
1723 int sqlite3_create_function_v2(
1724   sqlite3 *db,
1725   const char *zFunc,
1726   int nArg,
1727   int enc,
1728   void *p,
1729   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1730   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1731   void (*xFinal)(sqlite3_context*),
1732   void (*xDestroy)(void *)
1733 ){
1734   int rc = SQLITE_ERROR;
1735   FuncDestructor *pArg = 0;
1736 
1737 #ifdef SQLITE_ENABLE_API_ARMOR
1738   if( !sqlite3SafetyCheckOk(db) ){
1739     return SQLITE_MISUSE_BKPT;
1740   }
1741 #endif
1742   sqlite3_mutex_enter(db->mutex);
1743   if( xDestroy ){
1744     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1745     if( !pArg ){
1746       xDestroy(p);
1747       goto out;
1748     }
1749     pArg->xDestroy = xDestroy;
1750     pArg->pUserData = p;
1751   }
1752   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1753   if( pArg && pArg->nRef==0 ){
1754     assert( rc!=SQLITE_OK );
1755     xDestroy(p);
1756     sqlite3DbFree(db, pArg);
1757   }
1758 
1759  out:
1760   rc = sqlite3ApiExit(db, rc);
1761   sqlite3_mutex_leave(db->mutex);
1762   return rc;
1763 }
1764 
1765 #ifndef SQLITE_OMIT_UTF16
1766 int sqlite3_create_function16(
1767   sqlite3 *db,
1768   const void *zFunctionName,
1769   int nArg,
1770   int eTextRep,
1771   void *p,
1772   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1773   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1774   void (*xFinal)(sqlite3_context*)
1775 ){
1776   int rc;
1777   char *zFunc8;
1778 
1779 #ifdef SQLITE_ENABLE_API_ARMOR
1780   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1781 #endif
1782   sqlite3_mutex_enter(db->mutex);
1783   assert( !db->mallocFailed );
1784   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1785   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1786   sqlite3DbFree(db, zFunc8);
1787   rc = sqlite3ApiExit(db, rc);
1788   sqlite3_mutex_leave(db->mutex);
1789   return rc;
1790 }
1791 #endif
1792 
1793 
1794 /*
1795 ** Declare that a function has been overloaded by a virtual table.
1796 **
1797 ** If the function already exists as a regular global function, then
1798 ** this routine is a no-op.  If the function does not exist, then create
1799 ** a new one that always throws a run-time error.
1800 **
1801 ** When virtual tables intend to provide an overloaded function, they
1802 ** should call this routine to make sure the global function exists.
1803 ** A global function must exist in order for name resolution to work
1804 ** properly.
1805 */
1806 int sqlite3_overload_function(
1807   sqlite3 *db,
1808   const char *zName,
1809   int nArg
1810 ){
1811   int rc = SQLITE_OK;
1812 
1813 #ifdef SQLITE_ENABLE_API_ARMOR
1814   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1815     return SQLITE_MISUSE_BKPT;
1816   }
1817 #endif
1818   sqlite3_mutex_enter(db->mutex);
1819   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1820     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1821                            0, sqlite3InvalidFunction, 0, 0, 0);
1822   }
1823   rc = sqlite3ApiExit(db, rc);
1824   sqlite3_mutex_leave(db->mutex);
1825   return rc;
1826 }
1827 
1828 #ifndef SQLITE_OMIT_TRACE
1829 /*
1830 ** Register a trace function.  The pArg from the previously registered trace
1831 ** is returned.
1832 **
1833 ** A NULL trace function means that no tracing is executes.  A non-NULL
1834 ** trace is a pointer to a function that is invoked at the start of each
1835 ** SQL statement.
1836 */
1837 #ifndef SQLITE_OMIT_DEPRECATED
1838 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1839   void *pOld;
1840 
1841 #ifdef SQLITE_ENABLE_API_ARMOR
1842   if( !sqlite3SafetyCheckOk(db) ){
1843     (void)SQLITE_MISUSE_BKPT;
1844     return 0;
1845   }
1846 #endif
1847   sqlite3_mutex_enter(db->mutex);
1848   pOld = db->pTraceArg;
1849   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
1850   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
1851   db->pTraceArg = pArg;
1852   sqlite3_mutex_leave(db->mutex);
1853   return pOld;
1854 }
1855 #endif /* SQLITE_OMIT_DEPRECATED */
1856 
1857 /* Register a trace callback using the version-2 interface.
1858 */
1859 int sqlite3_trace_v2(
1860   sqlite3 *db,                               /* Trace this connection */
1861   unsigned mTrace,                           /* Mask of events to be traced */
1862   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
1863   void *pArg                                 /* Context */
1864 ){
1865 #ifdef SQLITE_ENABLE_API_ARMOR
1866   if( !sqlite3SafetyCheckOk(db) ){
1867     return SQLITE_MISUSE_BKPT;
1868   }
1869 #endif
1870   sqlite3_mutex_enter(db->mutex);
1871   if( mTrace==0 ) xTrace = 0;
1872   if( xTrace==0 ) mTrace = 0;
1873   db->mTrace = mTrace;
1874   db->xTrace = xTrace;
1875   db->pTraceArg = pArg;
1876   sqlite3_mutex_leave(db->mutex);
1877   return SQLITE_OK;
1878 }
1879 
1880 #ifndef SQLITE_OMIT_DEPRECATED
1881 /*
1882 ** Register a profile function.  The pArg from the previously registered
1883 ** profile function is returned.
1884 **
1885 ** A NULL profile function means that no profiling is executes.  A non-NULL
1886 ** profile is a pointer to a function that is invoked at the conclusion of
1887 ** each SQL statement that is run.
1888 */
1889 void *sqlite3_profile(
1890   sqlite3 *db,
1891   void (*xProfile)(void*,const char*,sqlite_uint64),
1892   void *pArg
1893 ){
1894   void *pOld;
1895 
1896 #ifdef SQLITE_ENABLE_API_ARMOR
1897   if( !sqlite3SafetyCheckOk(db) ){
1898     (void)SQLITE_MISUSE_BKPT;
1899     return 0;
1900   }
1901 #endif
1902   sqlite3_mutex_enter(db->mutex);
1903   pOld = db->pProfileArg;
1904   db->xProfile = xProfile;
1905   db->pProfileArg = pArg;
1906   sqlite3_mutex_leave(db->mutex);
1907   return pOld;
1908 }
1909 #endif /* SQLITE_OMIT_DEPRECATED */
1910 #endif /* SQLITE_OMIT_TRACE */
1911 
1912 /*
1913 ** Register a function to be invoked when a transaction commits.
1914 ** If the invoked function returns non-zero, then the commit becomes a
1915 ** rollback.
1916 */
1917 void *sqlite3_commit_hook(
1918   sqlite3 *db,              /* Attach the hook to this database */
1919   int (*xCallback)(void*),  /* Function to invoke on each commit */
1920   void *pArg                /* Argument to the function */
1921 ){
1922   void *pOld;
1923 
1924 #ifdef SQLITE_ENABLE_API_ARMOR
1925   if( !sqlite3SafetyCheckOk(db) ){
1926     (void)SQLITE_MISUSE_BKPT;
1927     return 0;
1928   }
1929 #endif
1930   sqlite3_mutex_enter(db->mutex);
1931   pOld = db->pCommitArg;
1932   db->xCommitCallback = xCallback;
1933   db->pCommitArg = pArg;
1934   sqlite3_mutex_leave(db->mutex);
1935   return pOld;
1936 }
1937 
1938 /*
1939 ** Register a callback to be invoked each time a row is updated,
1940 ** inserted or deleted using this database connection.
1941 */
1942 void *sqlite3_update_hook(
1943   sqlite3 *db,              /* Attach the hook to this database */
1944   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1945   void *pArg                /* Argument to the function */
1946 ){
1947   void *pRet;
1948 
1949 #ifdef SQLITE_ENABLE_API_ARMOR
1950   if( !sqlite3SafetyCheckOk(db) ){
1951     (void)SQLITE_MISUSE_BKPT;
1952     return 0;
1953   }
1954 #endif
1955   sqlite3_mutex_enter(db->mutex);
1956   pRet = db->pUpdateArg;
1957   db->xUpdateCallback = xCallback;
1958   db->pUpdateArg = pArg;
1959   sqlite3_mutex_leave(db->mutex);
1960   return pRet;
1961 }
1962 
1963 /*
1964 ** Register a callback to be invoked each time a transaction is rolled
1965 ** back by this database connection.
1966 */
1967 void *sqlite3_rollback_hook(
1968   sqlite3 *db,              /* Attach the hook to this database */
1969   void (*xCallback)(void*), /* Callback function */
1970   void *pArg                /* Argument to the function */
1971 ){
1972   void *pRet;
1973 
1974 #ifdef SQLITE_ENABLE_API_ARMOR
1975   if( !sqlite3SafetyCheckOk(db) ){
1976     (void)SQLITE_MISUSE_BKPT;
1977     return 0;
1978   }
1979 #endif
1980   sqlite3_mutex_enter(db->mutex);
1981   pRet = db->pRollbackArg;
1982   db->xRollbackCallback = xCallback;
1983   db->pRollbackArg = pArg;
1984   sqlite3_mutex_leave(db->mutex);
1985   return pRet;
1986 }
1987 
1988 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1989 /*
1990 ** Register a callback to be invoked each time a row is updated,
1991 ** inserted or deleted using this database connection.
1992 */
1993 void *sqlite3_preupdate_hook(
1994   sqlite3 *db,              /* Attach the hook to this database */
1995   void(*xCallback)(         /* Callback function */
1996     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
1997   void *pArg                /* First callback argument */
1998 ){
1999   void *pRet;
2000   sqlite3_mutex_enter(db->mutex);
2001   pRet = db->pPreUpdateArg;
2002   db->xPreUpdateCallback = xCallback;
2003   db->pPreUpdateArg = pArg;
2004   sqlite3_mutex_leave(db->mutex);
2005   return pRet;
2006 }
2007 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2008 
2009 #ifndef SQLITE_OMIT_WAL
2010 /*
2011 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2012 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2013 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2014 ** wal_autocheckpoint()).
2015 */
2016 int sqlite3WalDefaultHook(
2017   void *pClientData,     /* Argument */
2018   sqlite3 *db,           /* Connection */
2019   const char *zDb,       /* Database */
2020   int nFrame             /* Size of WAL */
2021 ){
2022   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2023     sqlite3BeginBenignMalloc();
2024     sqlite3_wal_checkpoint(db, zDb);
2025     sqlite3EndBenignMalloc();
2026   }
2027   return SQLITE_OK;
2028 }
2029 #endif /* SQLITE_OMIT_WAL */
2030 
2031 /*
2032 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2033 ** a database after committing a transaction if there are nFrame or
2034 ** more frames in the log file. Passing zero or a negative value as the
2035 ** nFrame parameter disables automatic checkpoints entirely.
2036 **
2037 ** The callback registered by this function replaces any existing callback
2038 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2039 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2040 ** configured by this function.
2041 */
2042 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2043 #ifdef SQLITE_OMIT_WAL
2044   UNUSED_PARAMETER(db);
2045   UNUSED_PARAMETER(nFrame);
2046 #else
2047 #ifdef SQLITE_ENABLE_API_ARMOR
2048   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2049 #endif
2050   if( nFrame>0 ){
2051     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2052   }else{
2053     sqlite3_wal_hook(db, 0, 0);
2054   }
2055 #endif
2056   return SQLITE_OK;
2057 }
2058 
2059 /*
2060 ** Register a callback to be invoked each time a transaction is written
2061 ** into the write-ahead-log by this database connection.
2062 */
2063 void *sqlite3_wal_hook(
2064   sqlite3 *db,                    /* Attach the hook to this db handle */
2065   int(*xCallback)(void *, sqlite3*, const char*, int),
2066   void *pArg                      /* First argument passed to xCallback() */
2067 ){
2068 #ifndef SQLITE_OMIT_WAL
2069   void *pRet;
2070 #ifdef SQLITE_ENABLE_API_ARMOR
2071   if( !sqlite3SafetyCheckOk(db) ){
2072     (void)SQLITE_MISUSE_BKPT;
2073     return 0;
2074   }
2075 #endif
2076   sqlite3_mutex_enter(db->mutex);
2077   pRet = db->pWalArg;
2078   db->xWalCallback = xCallback;
2079   db->pWalArg = pArg;
2080   sqlite3_mutex_leave(db->mutex);
2081   return pRet;
2082 #else
2083   return 0;
2084 #endif
2085 }
2086 
2087 /*
2088 ** Checkpoint database zDb.
2089 */
2090 int sqlite3_wal_checkpoint_v2(
2091   sqlite3 *db,                    /* Database handle */
2092   const char *zDb,                /* Name of attached database (or NULL) */
2093   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2094   int *pnLog,                     /* OUT: Size of WAL log in frames */
2095   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2096 ){
2097 #ifdef SQLITE_OMIT_WAL
2098   return SQLITE_OK;
2099 #else
2100   int rc;                         /* Return code */
2101   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2102 
2103 #ifdef SQLITE_ENABLE_API_ARMOR
2104   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2105 #endif
2106 
2107   /* Initialize the output variables to -1 in case an error occurs. */
2108   if( pnLog ) *pnLog = -1;
2109   if( pnCkpt ) *pnCkpt = -1;
2110 
2111   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2112   assert( SQLITE_CHECKPOINT_FULL==1 );
2113   assert( SQLITE_CHECKPOINT_RESTART==2 );
2114   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2115   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2116     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2117     ** mode: */
2118     return SQLITE_MISUSE;
2119   }
2120 
2121   sqlite3_mutex_enter(db->mutex);
2122   if( zDb && zDb[0] ){
2123     iDb = sqlite3FindDbName(db, zDb);
2124   }
2125   if( iDb<0 ){
2126     rc = SQLITE_ERROR;
2127     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2128   }else{
2129     db->busyHandler.nBusy = 0;
2130     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2131     sqlite3Error(db, rc);
2132   }
2133   rc = sqlite3ApiExit(db, rc);
2134 
2135   /* If there are no active statements, clear the interrupt flag at this
2136   ** point.  */
2137   if( db->nVdbeActive==0 ){
2138     db->u1.isInterrupted = 0;
2139   }
2140 
2141   sqlite3_mutex_leave(db->mutex);
2142   return rc;
2143 #endif
2144 }
2145 
2146 
2147 /*
2148 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2149 ** to contains a zero-length string, all attached databases are
2150 ** checkpointed.
2151 */
2152 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2153   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2154   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2155   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2156 }
2157 
2158 #ifndef SQLITE_OMIT_WAL
2159 /*
2160 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2161 ** not currently open in WAL mode.
2162 **
2163 ** If a transaction is open on the database being checkpointed, this
2164 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2165 ** an error occurs while running the checkpoint, an SQLite error code is
2166 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2167 **
2168 ** The mutex on database handle db should be held by the caller. The mutex
2169 ** associated with the specific b-tree being checkpointed is taken by
2170 ** this function while the checkpoint is running.
2171 **
2172 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2173 ** checkpointed. If an error is encountered it is returned immediately -
2174 ** no attempt is made to checkpoint any remaining databases.
2175 **
2176 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
2177 ** or TRUNCATE.
2178 */
2179 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2180   int rc = SQLITE_OK;             /* Return code */
2181   int i;                          /* Used to iterate through attached dbs */
2182   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2183 
2184   assert( sqlite3_mutex_held(db->mutex) );
2185   assert( !pnLog || *pnLog==-1 );
2186   assert( !pnCkpt || *pnCkpt==-1 );
2187 
2188   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2189     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2190       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2191       pnLog = 0;
2192       pnCkpt = 0;
2193       if( rc==SQLITE_BUSY ){
2194         bBusy = 1;
2195         rc = SQLITE_OK;
2196       }
2197     }
2198   }
2199 
2200   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2201 }
2202 #endif /* SQLITE_OMIT_WAL */
2203 
2204 /*
2205 ** This function returns true if main-memory should be used instead of
2206 ** a temporary file for transient pager files and statement journals.
2207 ** The value returned depends on the value of db->temp_store (runtime
2208 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2209 ** following table describes the relationship between these two values
2210 ** and this functions return value.
2211 **
2212 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2213 **   -----------------     --------------     ------------------------------
2214 **   0                     any                file      (return 0)
2215 **   1                     1                  file      (return 0)
2216 **   1                     2                  memory    (return 1)
2217 **   1                     0                  file      (return 0)
2218 **   2                     1                  file      (return 0)
2219 **   2                     2                  memory    (return 1)
2220 **   2                     0                  memory    (return 1)
2221 **   3                     any                memory    (return 1)
2222 */
2223 int sqlite3TempInMemory(const sqlite3 *db){
2224 #if SQLITE_TEMP_STORE==1
2225   return ( db->temp_store==2 );
2226 #endif
2227 #if SQLITE_TEMP_STORE==2
2228   return ( db->temp_store!=1 );
2229 #endif
2230 #if SQLITE_TEMP_STORE==3
2231   UNUSED_PARAMETER(db);
2232   return 1;
2233 #endif
2234 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2235   UNUSED_PARAMETER(db);
2236   return 0;
2237 #endif
2238 }
2239 
2240 /*
2241 ** Return UTF-8 encoded English language explanation of the most recent
2242 ** error.
2243 */
2244 const char *sqlite3_errmsg(sqlite3 *db){
2245   const char *z;
2246   if( !db ){
2247     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2248   }
2249   if( !sqlite3SafetyCheckSickOrOk(db) ){
2250     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2251   }
2252   sqlite3_mutex_enter(db->mutex);
2253   if( db->mallocFailed ){
2254     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2255   }else{
2256     testcase( db->pErr==0 );
2257     z = (char*)sqlite3_value_text(db->pErr);
2258     assert( !db->mallocFailed );
2259     if( z==0 ){
2260       z = sqlite3ErrStr(db->errCode);
2261     }
2262   }
2263   sqlite3_mutex_leave(db->mutex);
2264   return z;
2265 }
2266 
2267 #ifndef SQLITE_OMIT_UTF16
2268 /*
2269 ** Return UTF-16 encoded English language explanation of the most recent
2270 ** error.
2271 */
2272 const void *sqlite3_errmsg16(sqlite3 *db){
2273   static const u16 outOfMem[] = {
2274     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2275   };
2276   static const u16 misuse[] = {
2277     'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
2278     'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
2279     'm', 'i', 's', 'u', 's', 'e', 0
2280   };
2281 
2282   const void *z;
2283   if( !db ){
2284     return (void *)outOfMem;
2285   }
2286   if( !sqlite3SafetyCheckSickOrOk(db) ){
2287     return (void *)misuse;
2288   }
2289   sqlite3_mutex_enter(db->mutex);
2290   if( db->mallocFailed ){
2291     z = (void *)outOfMem;
2292   }else{
2293     z = sqlite3_value_text16(db->pErr);
2294     if( z==0 ){
2295       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2296       z = sqlite3_value_text16(db->pErr);
2297     }
2298     /* A malloc() may have failed within the call to sqlite3_value_text16()
2299     ** above. If this is the case, then the db->mallocFailed flag needs to
2300     ** be cleared before returning. Do this directly, instead of via
2301     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2302     */
2303     sqlite3OomClear(db);
2304   }
2305   sqlite3_mutex_leave(db->mutex);
2306   return z;
2307 }
2308 #endif /* SQLITE_OMIT_UTF16 */
2309 
2310 /*
2311 ** Return the most recent error code generated by an SQLite routine. If NULL is
2312 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2313 */
2314 int sqlite3_errcode(sqlite3 *db){
2315   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2316     return SQLITE_MISUSE_BKPT;
2317   }
2318   if( !db || db->mallocFailed ){
2319     return SQLITE_NOMEM_BKPT;
2320   }
2321   return db->errCode & db->errMask;
2322 }
2323 int sqlite3_extended_errcode(sqlite3 *db){
2324   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2325     return SQLITE_MISUSE_BKPT;
2326   }
2327   if( !db || db->mallocFailed ){
2328     return SQLITE_NOMEM_BKPT;
2329   }
2330   return db->errCode;
2331 }
2332 int sqlite3_system_errno(sqlite3 *db){
2333   return db ? db->iSysErrno : 0;
2334 }
2335 
2336 /*
2337 ** Return a string that describes the kind of error specified in the
2338 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2339 ** function.
2340 */
2341 const char *sqlite3_errstr(int rc){
2342   return sqlite3ErrStr(rc);
2343 }
2344 
2345 /*
2346 ** Create a new collating function for database "db".  The name is zName
2347 ** and the encoding is enc.
2348 */
2349 static int createCollation(
2350   sqlite3* db,
2351   const char *zName,
2352   u8 enc,
2353   void* pCtx,
2354   int(*xCompare)(void*,int,const void*,int,const void*),
2355   void(*xDel)(void*)
2356 ){
2357   CollSeq *pColl;
2358   int enc2;
2359 
2360   assert( sqlite3_mutex_held(db->mutex) );
2361 
2362   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2363   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2364   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2365   */
2366   enc2 = enc;
2367   testcase( enc2==SQLITE_UTF16 );
2368   testcase( enc2==SQLITE_UTF16_ALIGNED );
2369   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2370     enc2 = SQLITE_UTF16NATIVE;
2371   }
2372   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2373     return SQLITE_MISUSE_BKPT;
2374   }
2375 
2376   /* Check if this call is removing or replacing an existing collation
2377   ** sequence. If so, and there are active VMs, return busy. If there
2378   ** are no active VMs, invalidate any pre-compiled statements.
2379   */
2380   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2381   if( pColl && pColl->xCmp ){
2382     if( db->nVdbeActive ){
2383       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2384         "unable to delete/modify collation sequence due to active statements");
2385       return SQLITE_BUSY;
2386     }
2387     sqlite3ExpirePreparedStatements(db);
2388 
2389     /* If collation sequence pColl was created directly by a call to
2390     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2391     ** then any copies made by synthCollSeq() need to be invalidated.
2392     ** Also, collation destructor - CollSeq.xDel() - function may need
2393     ** to be called.
2394     */
2395     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2396       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2397       int j;
2398       for(j=0; j<3; j++){
2399         CollSeq *p = &aColl[j];
2400         if( p->enc==pColl->enc ){
2401           if( p->xDel ){
2402             p->xDel(p->pUser);
2403           }
2404           p->xCmp = 0;
2405         }
2406       }
2407     }
2408   }
2409 
2410   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2411   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2412   pColl->xCmp = xCompare;
2413   pColl->pUser = pCtx;
2414   pColl->xDel = xDel;
2415   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2416   sqlite3Error(db, SQLITE_OK);
2417   return SQLITE_OK;
2418 }
2419 
2420 
2421 /*
2422 ** This array defines hard upper bounds on limit values.  The
2423 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2424 ** #defines in sqlite3.h.
2425 */
2426 static const int aHardLimit[] = {
2427   SQLITE_MAX_LENGTH,
2428   SQLITE_MAX_SQL_LENGTH,
2429   SQLITE_MAX_COLUMN,
2430   SQLITE_MAX_EXPR_DEPTH,
2431   SQLITE_MAX_COMPOUND_SELECT,
2432   SQLITE_MAX_VDBE_OP,
2433   SQLITE_MAX_FUNCTION_ARG,
2434   SQLITE_MAX_ATTACHED,
2435   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2436   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2437   SQLITE_MAX_TRIGGER_DEPTH,
2438   SQLITE_MAX_WORKER_THREADS,
2439 };
2440 
2441 /*
2442 ** Make sure the hard limits are set to reasonable values
2443 */
2444 #if SQLITE_MAX_LENGTH<100
2445 # error SQLITE_MAX_LENGTH must be at least 100
2446 #endif
2447 #if SQLITE_MAX_SQL_LENGTH<100
2448 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2449 #endif
2450 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2451 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2452 #endif
2453 #if SQLITE_MAX_COMPOUND_SELECT<2
2454 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2455 #endif
2456 #if SQLITE_MAX_VDBE_OP<40
2457 # error SQLITE_MAX_VDBE_OP must be at least 40
2458 #endif
2459 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2460 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2461 #endif
2462 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2463 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2464 #endif
2465 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2466 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2467 #endif
2468 #if SQLITE_MAX_COLUMN>32767
2469 # error SQLITE_MAX_COLUMN must not exceed 32767
2470 #endif
2471 #if SQLITE_MAX_TRIGGER_DEPTH<1
2472 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2473 #endif
2474 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2475 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2476 #endif
2477 
2478 
2479 /*
2480 ** Change the value of a limit.  Report the old value.
2481 ** If an invalid limit index is supplied, report -1.
2482 ** Make no changes but still report the old value if the
2483 ** new limit is negative.
2484 **
2485 ** A new lower limit does not shrink existing constructs.
2486 ** It merely prevents new constructs that exceed the limit
2487 ** from forming.
2488 */
2489 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2490   int oldLimit;
2491 
2492 #ifdef SQLITE_ENABLE_API_ARMOR
2493   if( !sqlite3SafetyCheckOk(db) ){
2494     (void)SQLITE_MISUSE_BKPT;
2495     return -1;
2496   }
2497 #endif
2498 
2499   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2500   ** there is a hard upper bound set at compile-time by a C preprocessor
2501   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2502   ** "_MAX_".)
2503   */
2504   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2505   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2506   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2507   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2508   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2509   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2510   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2511   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2512   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2513                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2514   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2515   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2516   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2517   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2518 
2519 
2520   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2521     return -1;
2522   }
2523   oldLimit = db->aLimit[limitId];
2524   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2525     if( newLimit>aHardLimit[limitId] ){
2526       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2527     }
2528     db->aLimit[limitId] = newLimit;
2529   }
2530   return oldLimit;                     /* IMP: R-53341-35419 */
2531 }
2532 
2533 /*
2534 ** This function is used to parse both URIs and non-URI filenames passed by the
2535 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2536 ** URIs specified as part of ATTACH statements.
2537 **
2538 ** The first argument to this function is the name of the VFS to use (or
2539 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2540 ** query parameter. The second argument contains the URI (or non-URI filename)
2541 ** itself. When this function is called the *pFlags variable should contain
2542 ** the default flags to open the database handle with. The value stored in
2543 ** *pFlags may be updated before returning if the URI filename contains
2544 ** "cache=xxx" or "mode=xxx" query parameters.
2545 **
2546 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2547 ** the VFS that should be used to open the database file. *pzFile is set to
2548 ** point to a buffer containing the name of the file to open. It is the
2549 ** responsibility of the caller to eventually call sqlite3_free() to release
2550 ** this buffer.
2551 **
2552 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2553 ** may be set to point to a buffer containing an English language error
2554 ** message. It is the responsibility of the caller to eventually release
2555 ** this buffer by calling sqlite3_free().
2556 */
2557 int sqlite3ParseUri(
2558   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2559   const char *zUri,               /* Nul-terminated URI to parse */
2560   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2561   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2562   char **pzFile,                  /* OUT: Filename component of URI */
2563   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2564 ){
2565   int rc = SQLITE_OK;
2566   unsigned int flags = *pFlags;
2567   const char *zVfs = zDefaultVfs;
2568   char *zFile;
2569   char c;
2570   int nUri = sqlite3Strlen30(zUri);
2571 
2572   assert( *pzErrMsg==0 );
2573 
2574   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2575             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2576    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2577   ){
2578     char *zOpt;
2579     int eState;                   /* Parser state when parsing URI */
2580     int iIn;                      /* Input character index */
2581     int iOut = 0;                 /* Output character index */
2582     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2583 
2584     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2585     ** method that there may be extra parameters following the file-name.  */
2586     flags |= SQLITE_OPEN_URI;
2587 
2588     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2589     zFile = sqlite3_malloc64(nByte);
2590     if( !zFile ) return SQLITE_NOMEM_BKPT;
2591 
2592     iIn = 5;
2593 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2594     if( strncmp(zUri+5, "///", 3)==0 ){
2595       iIn = 7;
2596       /* The following condition causes URIs with five leading / characters
2597       ** like file://///host/path to be converted into UNCs like //host/path.
2598       ** The correct URI for that UNC has only two or four leading / characters
2599       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2600       ** common error, we are told, so we handle it as a special case. */
2601       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2602     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2603       iIn = 16;
2604     }
2605 #else
2606     /* Discard the scheme and authority segments of the URI. */
2607     if( zUri[5]=='/' && zUri[6]=='/' ){
2608       iIn = 7;
2609       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2610       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2611         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2612             iIn-7, &zUri[7]);
2613         rc = SQLITE_ERROR;
2614         goto parse_uri_out;
2615       }
2616     }
2617 #endif
2618 
2619     /* Copy the filename and any query parameters into the zFile buffer.
2620     ** Decode %HH escape codes along the way.
2621     **
2622     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2623     ** on the parsing context. As follows:
2624     **
2625     **   0: Parsing file-name.
2626     **   1: Parsing name section of a name=value query parameter.
2627     **   2: Parsing value section of a name=value query parameter.
2628     */
2629     eState = 0;
2630     while( (c = zUri[iIn])!=0 && c!='#' ){
2631       iIn++;
2632       if( c=='%'
2633        && sqlite3Isxdigit(zUri[iIn])
2634        && sqlite3Isxdigit(zUri[iIn+1])
2635       ){
2636         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2637         octet += sqlite3HexToInt(zUri[iIn++]);
2638 
2639         assert( octet>=0 && octet<256 );
2640         if( octet==0 ){
2641 #ifndef SQLITE_ENABLE_URI_00_ERROR
2642           /* This branch is taken when "%00" appears within the URI. In this
2643           ** case we ignore all text in the remainder of the path, name or
2644           ** value currently being parsed. So ignore the current character
2645           ** and skip to the next "?", "=" or "&", as appropriate. */
2646           while( (c = zUri[iIn])!=0 && c!='#'
2647               && (eState!=0 || c!='?')
2648               && (eState!=1 || (c!='=' && c!='&'))
2649               && (eState!=2 || c!='&')
2650           ){
2651             iIn++;
2652           }
2653           continue;
2654 #else
2655           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2656           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2657           rc = SQLITE_ERROR;
2658           goto parse_uri_out;
2659 #endif
2660         }
2661         c = octet;
2662       }else if( eState==1 && (c=='&' || c=='=') ){
2663         if( zFile[iOut-1]==0 ){
2664           /* An empty option name. Ignore this option altogether. */
2665           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2666           continue;
2667         }
2668         if( c=='&' ){
2669           zFile[iOut++] = '\0';
2670         }else{
2671           eState = 2;
2672         }
2673         c = 0;
2674       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2675         c = 0;
2676         eState = 1;
2677       }
2678       zFile[iOut++] = c;
2679     }
2680     if( eState==1 ) zFile[iOut++] = '\0';
2681     zFile[iOut++] = '\0';
2682     zFile[iOut++] = '\0';
2683 
2684     /* Check if there were any options specified that should be interpreted
2685     ** here. Options that are interpreted here include "vfs" and those that
2686     ** correspond to flags that may be passed to the sqlite3_open_v2()
2687     ** method. */
2688     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2689     while( zOpt[0] ){
2690       int nOpt = sqlite3Strlen30(zOpt);
2691       char *zVal = &zOpt[nOpt+1];
2692       int nVal = sqlite3Strlen30(zVal);
2693 
2694       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2695         zVfs = zVal;
2696       }else{
2697         struct OpenMode {
2698           const char *z;
2699           int mode;
2700         } *aMode = 0;
2701         char *zModeType = 0;
2702         int mask = 0;
2703         int limit = 0;
2704 
2705         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2706           static struct OpenMode aCacheMode[] = {
2707             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2708             { "private", SQLITE_OPEN_PRIVATECACHE },
2709             { 0, 0 }
2710           };
2711 
2712           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2713           aMode = aCacheMode;
2714           limit = mask;
2715           zModeType = "cache";
2716         }
2717         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2718           static struct OpenMode aOpenMode[] = {
2719             { "ro",  SQLITE_OPEN_READONLY },
2720             { "rw",  SQLITE_OPEN_READWRITE },
2721             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2722             { "memory", SQLITE_OPEN_MEMORY },
2723             { 0, 0 }
2724           };
2725 
2726           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2727                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2728           aMode = aOpenMode;
2729           limit = mask & flags;
2730           zModeType = "access";
2731         }
2732 
2733         if( aMode ){
2734           int i;
2735           int mode = 0;
2736           for(i=0; aMode[i].z; i++){
2737             const char *z = aMode[i].z;
2738             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2739               mode = aMode[i].mode;
2740               break;
2741             }
2742           }
2743           if( mode==0 ){
2744             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2745             rc = SQLITE_ERROR;
2746             goto parse_uri_out;
2747           }
2748           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2749             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2750                                         zModeType, zVal);
2751             rc = SQLITE_PERM;
2752             goto parse_uri_out;
2753           }
2754           flags = (flags & ~mask) | mode;
2755         }
2756       }
2757 
2758       zOpt = &zVal[nVal+1];
2759     }
2760 
2761   }else{
2762     zFile = sqlite3_malloc64(nUri+2);
2763     if( !zFile ) return SQLITE_NOMEM_BKPT;
2764     if( nUri ){
2765       memcpy(zFile, zUri, nUri);
2766     }
2767     zFile[nUri] = '\0';
2768     zFile[nUri+1] = '\0';
2769     flags &= ~SQLITE_OPEN_URI;
2770   }
2771 
2772   *ppVfs = sqlite3_vfs_find(zVfs);
2773   if( *ppVfs==0 ){
2774     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2775     rc = SQLITE_ERROR;
2776   }
2777  parse_uri_out:
2778   if( rc!=SQLITE_OK ){
2779     sqlite3_free(zFile);
2780     zFile = 0;
2781   }
2782   *pFlags = flags;
2783   *pzFile = zFile;
2784   return rc;
2785 }
2786 
2787 
2788 /*
2789 ** This routine does the work of opening a database on behalf of
2790 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2791 ** is UTF-8 encoded.
2792 */
2793 static int openDatabase(
2794   const char *zFilename, /* Database filename UTF-8 encoded */
2795   sqlite3 **ppDb,        /* OUT: Returned database handle */
2796   unsigned int flags,    /* Operational flags */
2797   const char *zVfs       /* Name of the VFS to use */
2798 ){
2799   sqlite3 *db;                    /* Store allocated handle here */
2800   int rc;                         /* Return code */
2801   int isThreadsafe;               /* True for threadsafe connections */
2802   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2803   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2804 
2805 #ifdef SQLITE_ENABLE_API_ARMOR
2806   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2807 #endif
2808   *ppDb = 0;
2809 #ifndef SQLITE_OMIT_AUTOINIT
2810   rc = sqlite3_initialize();
2811   if( rc ) return rc;
2812 #endif
2813 
2814   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2815     isThreadsafe = 0;
2816   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2817     isThreadsafe = 0;
2818   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2819     isThreadsafe = 1;
2820   }else{
2821     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2822   }
2823   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2824     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2825   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2826     flags |= SQLITE_OPEN_SHAREDCACHE;
2827   }
2828 
2829   /* Remove harmful bits from the flags parameter
2830   **
2831   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2832   ** dealt with in the previous code block.  Besides these, the only
2833   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2834   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2835   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2836   ** off all other flags.
2837   */
2838   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2839                SQLITE_OPEN_EXCLUSIVE |
2840                SQLITE_OPEN_MAIN_DB |
2841                SQLITE_OPEN_TEMP_DB |
2842                SQLITE_OPEN_TRANSIENT_DB |
2843                SQLITE_OPEN_MAIN_JOURNAL |
2844                SQLITE_OPEN_TEMP_JOURNAL |
2845                SQLITE_OPEN_SUBJOURNAL |
2846                SQLITE_OPEN_MASTER_JOURNAL |
2847                SQLITE_OPEN_NOMUTEX |
2848                SQLITE_OPEN_FULLMUTEX |
2849                SQLITE_OPEN_WAL
2850              );
2851 
2852   /* Allocate the sqlite data structure */
2853   db = sqlite3MallocZero( sizeof(sqlite3) );
2854   if( db==0 ) goto opendb_out;
2855   if( isThreadsafe ){
2856     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2857     if( db->mutex==0 ){
2858       sqlite3_free(db);
2859       db = 0;
2860       goto opendb_out;
2861     }
2862   }
2863   sqlite3_mutex_enter(db->mutex);
2864   db->errMask = 0xff;
2865   db->nDb = 2;
2866   db->magic = SQLITE_MAGIC_BUSY;
2867   db->aDb = db->aDbStatic;
2868 
2869   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2870   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2871   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2872   db->autoCommit = 1;
2873   db->nextAutovac = -1;
2874   db->szMmap = sqlite3GlobalConfig.szMmap;
2875   db->nextPagesize = 0;
2876   db->nMaxSorterMmap = 0x7FFFFFFF;
2877   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2878 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2879                  | SQLITE_AutoIndex
2880 #endif
2881 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2882                  | SQLITE_CkptFullFSync
2883 #endif
2884 #if SQLITE_DEFAULT_FILE_FORMAT<4
2885                  | SQLITE_LegacyFileFmt
2886 #endif
2887 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2888                  | SQLITE_LoadExtension
2889 #endif
2890 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2891                  | SQLITE_RecTriggers
2892 #endif
2893 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2894                  | SQLITE_ForeignKeys
2895 #endif
2896 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2897                  | SQLITE_ReverseOrder
2898 #endif
2899 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2900                  | SQLITE_CellSizeCk
2901 #endif
2902 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
2903                  | SQLITE_Fts3Tokenizer
2904 #endif
2905 #if defined(SQLITE_ENABLE_QPSG)
2906                  | SQLITE_EnableQPSG
2907 #endif
2908       ;
2909   sqlite3HashInit(&db->aCollSeq);
2910 #ifndef SQLITE_OMIT_VIRTUALTABLE
2911   sqlite3HashInit(&db->aModule);
2912 #endif
2913 
2914   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2915   ** and UTF-16, so add a version for each to avoid any unnecessary
2916   ** conversions. The only error that can occur here is a malloc() failure.
2917   **
2918   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2919   ** functions:
2920   */
2921   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2922   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2923   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2924   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2925   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2926   if( db->mallocFailed ){
2927     goto opendb_out;
2928   }
2929   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2930   ** strings is BINARY.
2931   */
2932   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2933   assert( db->pDfltColl!=0 );
2934 
2935   /* Parse the filename/URI argument
2936   **
2937   ** Only allow sensible combinations of bits in the flags argument.
2938   ** Throw an error if any non-sense combination is used.  If we
2939   ** do not block illegal combinations here, it could trigger
2940   ** assert() statements in deeper layers.  Sensible combinations
2941   ** are:
2942   **
2943   **  1:  SQLITE_OPEN_READONLY
2944   **  2:  SQLITE_OPEN_READWRITE
2945   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2946   */
2947   db->openFlags = flags;
2948   assert( SQLITE_OPEN_READONLY  == 0x01 );
2949   assert( SQLITE_OPEN_READWRITE == 0x02 );
2950   assert( SQLITE_OPEN_CREATE    == 0x04 );
2951   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2952   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2953   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2954   if( ((1<<(flags&7)) & 0x46)==0 ){
2955     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2956   }else{
2957     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2958   }
2959   if( rc!=SQLITE_OK ){
2960     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2961     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2962     sqlite3_free(zErrMsg);
2963     goto opendb_out;
2964   }
2965 
2966   /* Open the backend database driver */
2967   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2968                         flags | SQLITE_OPEN_MAIN_DB);
2969   if( rc!=SQLITE_OK ){
2970     if( rc==SQLITE_IOERR_NOMEM ){
2971       rc = SQLITE_NOMEM_BKPT;
2972     }
2973     sqlite3Error(db, rc);
2974     goto opendb_out;
2975   }
2976   sqlite3BtreeEnter(db->aDb[0].pBt);
2977   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2978   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2979   sqlite3BtreeLeave(db->aDb[0].pBt);
2980   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2981 
2982   /* The default safety_level for the main database is FULL; for the temp
2983   ** database it is OFF. This matches the pager layer defaults.
2984   */
2985   db->aDb[0].zDbSName = "main";
2986   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
2987   db->aDb[1].zDbSName = "temp";
2988   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
2989 
2990   db->magic = SQLITE_MAGIC_OPEN;
2991   if( db->mallocFailed ){
2992     goto opendb_out;
2993   }
2994 
2995   /* Register all built-in functions, but do not attempt to read the
2996   ** database schema yet. This is delayed until the first time the database
2997   ** is accessed.
2998   */
2999   sqlite3Error(db, SQLITE_OK);
3000   sqlite3RegisterPerConnectionBuiltinFunctions(db);
3001   rc = sqlite3_errcode(db);
3002 
3003 #ifdef SQLITE_ENABLE_FTS5
3004   /* Register any built-in FTS5 module before loading the automatic
3005   ** extensions. This allows automatic extensions to register FTS5
3006   ** tokenizers and auxiliary functions.  */
3007   if( !db->mallocFailed && rc==SQLITE_OK ){
3008     rc = sqlite3Fts5Init(db);
3009   }
3010 #endif
3011 
3012   /* Load automatic extensions - extensions that have been registered
3013   ** using the sqlite3_automatic_extension() API.
3014   */
3015   if( rc==SQLITE_OK ){
3016     sqlite3AutoLoadExtensions(db);
3017     rc = sqlite3_errcode(db);
3018     if( rc!=SQLITE_OK ){
3019       goto opendb_out;
3020     }
3021   }
3022 
3023 #ifdef SQLITE_ENABLE_FTS1
3024   if( !db->mallocFailed ){
3025     extern int sqlite3Fts1Init(sqlite3*);
3026     rc = sqlite3Fts1Init(db);
3027   }
3028 #endif
3029 
3030 #ifdef SQLITE_ENABLE_FTS2
3031   if( !db->mallocFailed && rc==SQLITE_OK ){
3032     extern int sqlite3Fts2Init(sqlite3*);
3033     rc = sqlite3Fts2Init(db);
3034   }
3035 #endif
3036 
3037 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3038   if( !db->mallocFailed && rc==SQLITE_OK ){
3039     rc = sqlite3Fts3Init(db);
3040   }
3041 #endif
3042 
3043 #ifdef SQLITE_ENABLE_ICU
3044   if( !db->mallocFailed && rc==SQLITE_OK ){
3045     rc = sqlite3IcuInit(db);
3046   }
3047 #endif
3048 
3049 #ifdef SQLITE_ENABLE_RTREE
3050   if( !db->mallocFailed && rc==SQLITE_OK){
3051     rc = sqlite3RtreeInit(db);
3052   }
3053 #endif
3054 
3055 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3056   if( !db->mallocFailed && rc==SQLITE_OK){
3057     rc = sqlite3DbstatRegister(db);
3058   }
3059 #endif
3060 
3061 #ifdef SQLITE_ENABLE_JSON1
3062   if( !db->mallocFailed && rc==SQLITE_OK){
3063     rc = sqlite3Json1Init(db);
3064   }
3065 #endif
3066 
3067 #ifdef SQLITE_ENABLE_STMTVTAB
3068   if( !db->mallocFailed && rc==SQLITE_OK){
3069     rc = sqlite3StmtVtabInit(db);
3070   }
3071 #endif
3072 
3073   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3074   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3075   ** mode.  Doing nothing at all also makes NORMAL the default.
3076   */
3077 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3078   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3079   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3080                           SQLITE_DEFAULT_LOCKING_MODE);
3081 #endif
3082 
3083   if( rc ) sqlite3Error(db, rc);
3084 
3085   /* Enable the lookaside-malloc subsystem */
3086   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3087                         sqlite3GlobalConfig.nLookaside);
3088 
3089   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3090 
3091 opendb_out:
3092   if( db ){
3093     assert( db->mutex!=0 || isThreadsafe==0
3094            || sqlite3GlobalConfig.bFullMutex==0 );
3095     sqlite3_mutex_leave(db->mutex);
3096   }
3097   rc = sqlite3_errcode(db);
3098   assert( db!=0 || rc==SQLITE_NOMEM );
3099   if( rc==SQLITE_NOMEM ){
3100     sqlite3_close(db);
3101     db = 0;
3102   }else if( rc!=SQLITE_OK ){
3103     db->magic = SQLITE_MAGIC_SICK;
3104   }
3105   *ppDb = db;
3106 #ifdef SQLITE_ENABLE_SQLLOG
3107   if( sqlite3GlobalConfig.xSqllog ){
3108     /* Opening a db handle. Fourth parameter is passed 0. */
3109     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3110     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3111   }
3112 #endif
3113 #if defined(SQLITE_HAS_CODEC)
3114   if( rc==SQLITE_OK ){
3115     const char *zKey;
3116     if( (zKey = sqlite3_uri_parameter(zOpen, "hexkey"))!=0 && zKey[0] ){
3117       u8 iByte;
3118       int i;
3119       char zDecoded[40];
3120       for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
3121         iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
3122         if( (i&1)!=0 ) zDecoded[i/2] = iByte;
3123       }
3124       sqlite3_key_v2(db, 0, zDecoded, i/2);
3125     }else if( (zKey = sqlite3_uri_parameter(zOpen, "key"))!=0 ){
3126       sqlite3_key_v2(db, 0, zKey, sqlite3Strlen30(zKey));
3127     }
3128   }
3129 #endif
3130   sqlite3_free(zOpen);
3131   return rc & 0xff;
3132 }
3133 
3134 /*
3135 ** Open a new database handle.
3136 */
3137 int sqlite3_open(
3138   const char *zFilename,
3139   sqlite3 **ppDb
3140 ){
3141   return openDatabase(zFilename, ppDb,
3142                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3143 }
3144 int sqlite3_open_v2(
3145   const char *filename,   /* Database filename (UTF-8) */
3146   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3147   int flags,              /* Flags */
3148   const char *zVfs        /* Name of VFS module to use */
3149 ){
3150   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3151 }
3152 
3153 #ifndef SQLITE_OMIT_UTF16
3154 /*
3155 ** Open a new database handle.
3156 */
3157 int sqlite3_open16(
3158   const void *zFilename,
3159   sqlite3 **ppDb
3160 ){
3161   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3162   sqlite3_value *pVal;
3163   int rc;
3164 
3165 #ifdef SQLITE_ENABLE_API_ARMOR
3166   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3167 #endif
3168   *ppDb = 0;
3169 #ifndef SQLITE_OMIT_AUTOINIT
3170   rc = sqlite3_initialize();
3171   if( rc ) return rc;
3172 #endif
3173   if( zFilename==0 ) zFilename = "\000\000";
3174   pVal = sqlite3ValueNew(0);
3175   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3176   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3177   if( zFilename8 ){
3178     rc = openDatabase(zFilename8, ppDb,
3179                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3180     assert( *ppDb || rc==SQLITE_NOMEM );
3181     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3182       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3183     }
3184   }else{
3185     rc = SQLITE_NOMEM_BKPT;
3186   }
3187   sqlite3ValueFree(pVal);
3188 
3189   return rc & 0xff;
3190 }
3191 #endif /* SQLITE_OMIT_UTF16 */
3192 
3193 /*
3194 ** Register a new collation sequence with the database handle db.
3195 */
3196 int sqlite3_create_collation(
3197   sqlite3* db,
3198   const char *zName,
3199   int enc,
3200   void* pCtx,
3201   int(*xCompare)(void*,int,const void*,int,const void*)
3202 ){
3203   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3204 }
3205 
3206 /*
3207 ** Register a new collation sequence with the database handle db.
3208 */
3209 int sqlite3_create_collation_v2(
3210   sqlite3* db,
3211   const char *zName,
3212   int enc,
3213   void* pCtx,
3214   int(*xCompare)(void*,int,const void*,int,const void*),
3215   void(*xDel)(void*)
3216 ){
3217   int rc;
3218 
3219 #ifdef SQLITE_ENABLE_API_ARMOR
3220   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3221 #endif
3222   sqlite3_mutex_enter(db->mutex);
3223   assert( !db->mallocFailed );
3224   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3225   rc = sqlite3ApiExit(db, rc);
3226   sqlite3_mutex_leave(db->mutex);
3227   return rc;
3228 }
3229 
3230 #ifndef SQLITE_OMIT_UTF16
3231 /*
3232 ** Register a new collation sequence with the database handle db.
3233 */
3234 int sqlite3_create_collation16(
3235   sqlite3* db,
3236   const void *zName,
3237   int enc,
3238   void* pCtx,
3239   int(*xCompare)(void*,int,const void*,int,const void*)
3240 ){
3241   int rc = SQLITE_OK;
3242   char *zName8;
3243 
3244 #ifdef SQLITE_ENABLE_API_ARMOR
3245   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3246 #endif
3247   sqlite3_mutex_enter(db->mutex);
3248   assert( !db->mallocFailed );
3249   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3250   if( zName8 ){
3251     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3252     sqlite3DbFree(db, zName8);
3253   }
3254   rc = sqlite3ApiExit(db, rc);
3255   sqlite3_mutex_leave(db->mutex);
3256   return rc;
3257 }
3258 #endif /* SQLITE_OMIT_UTF16 */
3259 
3260 /*
3261 ** Register a collation sequence factory callback with the database handle
3262 ** db. Replace any previously installed collation sequence factory.
3263 */
3264 int sqlite3_collation_needed(
3265   sqlite3 *db,
3266   void *pCollNeededArg,
3267   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3268 ){
3269 #ifdef SQLITE_ENABLE_API_ARMOR
3270   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3271 #endif
3272   sqlite3_mutex_enter(db->mutex);
3273   db->xCollNeeded = xCollNeeded;
3274   db->xCollNeeded16 = 0;
3275   db->pCollNeededArg = pCollNeededArg;
3276   sqlite3_mutex_leave(db->mutex);
3277   return SQLITE_OK;
3278 }
3279 
3280 #ifndef SQLITE_OMIT_UTF16
3281 /*
3282 ** Register a collation sequence factory callback with the database handle
3283 ** db. Replace any previously installed collation sequence factory.
3284 */
3285 int sqlite3_collation_needed16(
3286   sqlite3 *db,
3287   void *pCollNeededArg,
3288   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3289 ){
3290 #ifdef SQLITE_ENABLE_API_ARMOR
3291   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3292 #endif
3293   sqlite3_mutex_enter(db->mutex);
3294   db->xCollNeeded = 0;
3295   db->xCollNeeded16 = xCollNeeded16;
3296   db->pCollNeededArg = pCollNeededArg;
3297   sqlite3_mutex_leave(db->mutex);
3298   return SQLITE_OK;
3299 }
3300 #endif /* SQLITE_OMIT_UTF16 */
3301 
3302 #ifndef SQLITE_OMIT_DEPRECATED
3303 /*
3304 ** This function is now an anachronism. It used to be used to recover from a
3305 ** malloc() failure, but SQLite now does this automatically.
3306 */
3307 int sqlite3_global_recover(void){
3308   return SQLITE_OK;
3309 }
3310 #endif
3311 
3312 /*
3313 ** Test to see whether or not the database connection is in autocommit
3314 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3315 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3316 ** by the next COMMIT or ROLLBACK.
3317 */
3318 int sqlite3_get_autocommit(sqlite3 *db){
3319 #ifdef SQLITE_ENABLE_API_ARMOR
3320   if( !sqlite3SafetyCheckOk(db) ){
3321     (void)SQLITE_MISUSE_BKPT;
3322     return 0;
3323   }
3324 #endif
3325   return db->autoCommit;
3326 }
3327 
3328 /*
3329 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3330 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3331 ** constants.  They serve two purposes:
3332 **
3333 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3334 **       to detect when version error conditions occurs.
3335 **
3336 **   2.  Invoke sqlite3_log() to provide the source code location where
3337 **       a low-level error is first detected.
3338 */
3339 static int reportError(int iErr, int lineno, const char *zType){
3340   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3341               zType, lineno, 20+sqlite3_sourceid());
3342   return iErr;
3343 }
3344 int sqlite3CorruptError(int lineno){
3345   testcase( sqlite3GlobalConfig.xLog!=0 );
3346   return reportError(SQLITE_CORRUPT, lineno, "database corruption");
3347 }
3348 int sqlite3MisuseError(int lineno){
3349   testcase( sqlite3GlobalConfig.xLog!=0 );
3350   return reportError(SQLITE_MISUSE, lineno, "misuse");
3351 }
3352 int sqlite3CantopenError(int lineno){
3353   testcase( sqlite3GlobalConfig.xLog!=0 );
3354   return reportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3355 }
3356 #ifdef SQLITE_DEBUG
3357 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3358   char zMsg[100];
3359   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3360   testcase( sqlite3GlobalConfig.xLog!=0 );
3361   return reportError(SQLITE_CORRUPT, lineno, zMsg);
3362 }
3363 int sqlite3NomemError(int lineno){
3364   testcase( sqlite3GlobalConfig.xLog!=0 );
3365   return reportError(SQLITE_NOMEM, lineno, "OOM");
3366 }
3367 int sqlite3IoerrnomemError(int lineno){
3368   testcase( sqlite3GlobalConfig.xLog!=0 );
3369   return reportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3370 }
3371 #endif
3372 
3373 #ifndef SQLITE_OMIT_DEPRECATED
3374 /*
3375 ** This is a convenience routine that makes sure that all thread-specific
3376 ** data for this thread has been deallocated.
3377 **
3378 ** SQLite no longer uses thread-specific data so this routine is now a
3379 ** no-op.  It is retained for historical compatibility.
3380 */
3381 void sqlite3_thread_cleanup(void){
3382 }
3383 #endif
3384 
3385 /*
3386 ** Return meta information about a specific column of a database table.
3387 ** See comment in sqlite3.h (sqlite.h.in) for details.
3388 */
3389 int sqlite3_table_column_metadata(
3390   sqlite3 *db,                /* Connection handle */
3391   const char *zDbName,        /* Database name or NULL */
3392   const char *zTableName,     /* Table name */
3393   const char *zColumnName,    /* Column name */
3394   char const **pzDataType,    /* OUTPUT: Declared data type */
3395   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3396   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3397   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3398   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3399 ){
3400   int rc;
3401   char *zErrMsg = 0;
3402   Table *pTab = 0;
3403   Column *pCol = 0;
3404   int iCol = 0;
3405   char const *zDataType = 0;
3406   char const *zCollSeq = 0;
3407   int notnull = 0;
3408   int primarykey = 0;
3409   int autoinc = 0;
3410 
3411 
3412 #ifdef SQLITE_ENABLE_API_ARMOR
3413   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3414     return SQLITE_MISUSE_BKPT;
3415   }
3416 #endif
3417 
3418   /* Ensure the database schema has been loaded */
3419   sqlite3_mutex_enter(db->mutex);
3420   sqlite3BtreeEnterAll(db);
3421   rc = sqlite3Init(db, &zErrMsg);
3422   if( SQLITE_OK!=rc ){
3423     goto error_out;
3424   }
3425 
3426   /* Locate the table in question */
3427   pTab = sqlite3FindTable(db, zTableName, zDbName);
3428   if( !pTab || pTab->pSelect ){
3429     pTab = 0;
3430     goto error_out;
3431   }
3432 
3433   /* Find the column for which info is requested */
3434   if( zColumnName==0 ){
3435     /* Query for existance of table only */
3436   }else{
3437     for(iCol=0; iCol<pTab->nCol; iCol++){
3438       pCol = &pTab->aCol[iCol];
3439       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3440         break;
3441       }
3442     }
3443     if( iCol==pTab->nCol ){
3444       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3445         iCol = pTab->iPKey;
3446         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3447       }else{
3448         pTab = 0;
3449         goto error_out;
3450       }
3451     }
3452   }
3453 
3454   /* The following block stores the meta information that will be returned
3455   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3456   ** and autoinc. At this point there are two possibilities:
3457   **
3458   **     1. The specified column name was rowid", "oid" or "_rowid_"
3459   **        and there is no explicitly declared IPK column.
3460   **
3461   **     2. The table is not a view and the column name identified an
3462   **        explicitly declared column. Copy meta information from *pCol.
3463   */
3464   if( pCol ){
3465     zDataType = sqlite3ColumnType(pCol,0);
3466     zCollSeq = pCol->zColl;
3467     notnull = pCol->notNull!=0;
3468     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3469     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3470   }else{
3471     zDataType = "INTEGER";
3472     primarykey = 1;
3473   }
3474   if( !zCollSeq ){
3475     zCollSeq = sqlite3StrBINARY;
3476   }
3477 
3478 error_out:
3479   sqlite3BtreeLeaveAll(db);
3480 
3481   /* Whether the function call succeeded or failed, set the output parameters
3482   ** to whatever their local counterparts contain. If an error did occur,
3483   ** this has the effect of zeroing all output parameters.
3484   */
3485   if( pzDataType ) *pzDataType = zDataType;
3486   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3487   if( pNotNull ) *pNotNull = notnull;
3488   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3489   if( pAutoinc ) *pAutoinc = autoinc;
3490 
3491   if( SQLITE_OK==rc && !pTab ){
3492     sqlite3DbFree(db, zErrMsg);
3493     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3494         zColumnName);
3495     rc = SQLITE_ERROR;
3496   }
3497   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3498   sqlite3DbFree(db, zErrMsg);
3499   rc = sqlite3ApiExit(db, rc);
3500   sqlite3_mutex_leave(db->mutex);
3501   return rc;
3502 }
3503 
3504 /*
3505 ** Sleep for a little while.  Return the amount of time slept.
3506 */
3507 int sqlite3_sleep(int ms){
3508   sqlite3_vfs *pVfs;
3509   int rc;
3510   pVfs = sqlite3_vfs_find(0);
3511   if( pVfs==0 ) return 0;
3512 
3513   /* This function works in milliseconds, but the underlying OsSleep()
3514   ** API uses microseconds. Hence the 1000's.
3515   */
3516   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3517   return rc;
3518 }
3519 
3520 /*
3521 ** Enable or disable the extended result codes.
3522 */
3523 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3524 #ifdef SQLITE_ENABLE_API_ARMOR
3525   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3526 #endif
3527   sqlite3_mutex_enter(db->mutex);
3528   db->errMask = onoff ? 0xffffffff : 0xff;
3529   sqlite3_mutex_leave(db->mutex);
3530   return SQLITE_OK;
3531 }
3532 
3533 /*
3534 ** Invoke the xFileControl method on a particular database.
3535 */
3536 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3537   int rc = SQLITE_ERROR;
3538   Btree *pBtree;
3539 
3540 #ifdef SQLITE_ENABLE_API_ARMOR
3541   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3542 #endif
3543   sqlite3_mutex_enter(db->mutex);
3544   pBtree = sqlite3DbNameToBtree(db, zDbName);
3545   if( pBtree ){
3546     Pager *pPager;
3547     sqlite3_file *fd;
3548     sqlite3BtreeEnter(pBtree);
3549     pPager = sqlite3BtreePager(pBtree);
3550     assert( pPager!=0 );
3551     fd = sqlite3PagerFile(pPager);
3552     assert( fd!=0 );
3553     if( op==SQLITE_FCNTL_FILE_POINTER ){
3554       *(sqlite3_file**)pArg = fd;
3555       rc = SQLITE_OK;
3556     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3557       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3558       rc = SQLITE_OK;
3559     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3560       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3561       rc = SQLITE_OK;
3562     }else if( fd->pMethods ){
3563       rc = sqlite3OsFileControl(fd, op, pArg);
3564     }else{
3565       rc = SQLITE_NOTFOUND;
3566     }
3567     sqlite3BtreeLeave(pBtree);
3568   }
3569   sqlite3_mutex_leave(db->mutex);
3570   return rc;
3571 }
3572 
3573 /*
3574 ** Interface to the testing logic.
3575 */
3576 int sqlite3_test_control(int op, ...){
3577   int rc = 0;
3578 #ifdef SQLITE_UNTESTABLE
3579   UNUSED_PARAMETER(op);
3580 #else
3581   va_list ap;
3582   va_start(ap, op);
3583   switch( op ){
3584 
3585     /*
3586     ** Save the current state of the PRNG.
3587     */
3588     case SQLITE_TESTCTRL_PRNG_SAVE: {
3589       sqlite3PrngSaveState();
3590       break;
3591     }
3592 
3593     /*
3594     ** Restore the state of the PRNG to the last state saved using
3595     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3596     ** this verb acts like PRNG_RESET.
3597     */
3598     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3599       sqlite3PrngRestoreState();
3600       break;
3601     }
3602 
3603     /*
3604     ** Reset the PRNG back to its uninitialized state.  The next call
3605     ** to sqlite3_randomness() will reseed the PRNG using a single call
3606     ** to the xRandomness method of the default VFS.
3607     */
3608     case SQLITE_TESTCTRL_PRNG_RESET: {
3609       sqlite3_randomness(0,0);
3610       break;
3611     }
3612 
3613     /*
3614     **  sqlite3_test_control(BITVEC_TEST, size, program)
3615     **
3616     ** Run a test against a Bitvec object of size.  The program argument
3617     ** is an array of integers that defines the test.  Return -1 on a
3618     ** memory allocation error, 0 on success, or non-zero for an error.
3619     ** See the sqlite3BitvecBuiltinTest() for additional information.
3620     */
3621     case SQLITE_TESTCTRL_BITVEC_TEST: {
3622       int sz = va_arg(ap, int);
3623       int *aProg = va_arg(ap, int*);
3624       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3625       break;
3626     }
3627 
3628     /*
3629     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3630     **
3631     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3632     ** if xCallback is not NULL.
3633     **
3634     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3635     ** is called immediately after installing the new callback and the return
3636     ** value from sqlite3FaultSim(0) becomes the return from
3637     ** sqlite3_test_control().
3638     */
3639     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3640       /* MSVC is picky about pulling func ptrs from va lists.
3641       ** http://support.microsoft.com/kb/47961
3642       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3643       */
3644       typedef int(*TESTCALLBACKFUNC_t)(int);
3645       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3646       rc = sqlite3FaultSim(0);
3647       break;
3648     }
3649 
3650     /*
3651     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3652     **
3653     ** Register hooks to call to indicate which malloc() failures
3654     ** are benign.
3655     */
3656     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3657       typedef void (*void_function)(void);
3658       void_function xBenignBegin;
3659       void_function xBenignEnd;
3660       xBenignBegin = va_arg(ap, void_function);
3661       xBenignEnd = va_arg(ap, void_function);
3662       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3663       break;
3664     }
3665 
3666     /*
3667     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3668     **
3669     ** Set the PENDING byte to the value in the argument, if X>0.
3670     ** Make no changes if X==0.  Return the value of the pending byte
3671     ** as it existing before this routine was called.
3672     **
3673     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3674     ** an incompatible database file format.  Changing the PENDING byte
3675     ** while any database connection is open results in undefined and
3676     ** deleterious behavior.
3677     */
3678     case SQLITE_TESTCTRL_PENDING_BYTE: {
3679       rc = PENDING_BYTE;
3680 #ifndef SQLITE_OMIT_WSD
3681       {
3682         unsigned int newVal = va_arg(ap, unsigned int);
3683         if( newVal ) sqlite3PendingByte = newVal;
3684       }
3685 #endif
3686       break;
3687     }
3688 
3689     /*
3690     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3691     **
3692     ** This action provides a run-time test to see whether or not
3693     ** assert() was enabled at compile-time.  If X is true and assert()
3694     ** is enabled, then the return value is true.  If X is true and
3695     ** assert() is disabled, then the return value is zero.  If X is
3696     ** false and assert() is enabled, then the assertion fires and the
3697     ** process aborts.  If X is false and assert() is disabled, then the
3698     ** return value is zero.
3699     */
3700     case SQLITE_TESTCTRL_ASSERT: {
3701       volatile int x = 0;
3702       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3703       rc = x;
3704       break;
3705     }
3706 
3707 
3708     /*
3709     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3710     **
3711     ** This action provides a run-time test to see how the ALWAYS and
3712     ** NEVER macros were defined at compile-time.
3713     **
3714     ** The return value is ALWAYS(X).
3715     **
3716     ** The recommended test is X==2.  If the return value is 2, that means
3717     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3718     ** default setting.  If the return value is 1, then ALWAYS() is either
3719     ** hard-coded to true or else it asserts if its argument is false.
3720     ** The first behavior (hard-coded to true) is the case if
3721     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3722     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3723     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3724     **
3725     ** The run-time test procedure might look something like this:
3726     **
3727     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3728     **      // ALWAYS() and NEVER() are no-op pass-through macros
3729     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3730     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3731     **    }else{
3732     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3733     **    }
3734     */
3735     case SQLITE_TESTCTRL_ALWAYS: {
3736       int x = va_arg(ap,int);
3737       rc = ALWAYS(x);
3738       break;
3739     }
3740 
3741     /*
3742     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3743     **
3744     ** The integer returned reveals the byte-order of the computer on which
3745     ** SQLite is running:
3746     **
3747     **       1     big-endian,    determined at run-time
3748     **      10     little-endian, determined at run-time
3749     **  432101     big-endian,    determined at compile-time
3750     **  123410     little-endian, determined at compile-time
3751     */
3752     case SQLITE_TESTCTRL_BYTEORDER: {
3753       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3754       break;
3755     }
3756 
3757     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3758     **
3759     ** Set the nReserve size to N for the main database on the database
3760     ** connection db.
3761     */
3762     case SQLITE_TESTCTRL_RESERVE: {
3763       sqlite3 *db = va_arg(ap, sqlite3*);
3764       int x = va_arg(ap,int);
3765       sqlite3_mutex_enter(db->mutex);
3766       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3767       sqlite3_mutex_leave(db->mutex);
3768       break;
3769     }
3770 
3771     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3772     **
3773     ** Enable or disable various optimizations for testing purposes.  The
3774     ** argument N is a bitmask of optimizations to be disabled.  For normal
3775     ** operation N should be 0.  The idea is that a test program (like the
3776     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3777     ** with various optimizations disabled to verify that the same answer
3778     ** is obtained in every case.
3779     */
3780     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3781       sqlite3 *db = va_arg(ap, sqlite3*);
3782       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3783       break;
3784     }
3785 
3786 #ifdef SQLITE_N_KEYWORD
3787     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3788     **
3789     ** If zWord is a keyword recognized by the parser, then return the
3790     ** number of keywords.  Or if zWord is not a keyword, return 0.
3791     **
3792     ** This test feature is only available in the amalgamation since
3793     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3794     ** is built using separate source files.
3795     */
3796     case SQLITE_TESTCTRL_ISKEYWORD: {
3797       const char *zWord = va_arg(ap, const char*);
3798       int n = sqlite3Strlen30(zWord);
3799       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3800       break;
3801     }
3802 #endif
3803 
3804     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3805     **
3806     ** If parameter onoff is non-zero, configure the wrappers so that all
3807     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3808     ** undo this setting.
3809     */
3810     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3811       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3812       break;
3813     }
3814 
3815     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3816     **
3817     ** Set or clear a flag that indicates that the database file is always well-
3818     ** formed and never corrupt.  This flag is clear by default, indicating that
3819     ** database files might have arbitrary corruption.  Setting the flag during
3820     ** testing causes certain assert() statements in the code to be activated
3821     ** that demonstrat invariants on well-formed database files.
3822     */
3823     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3824       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3825       break;
3826     }
3827 
3828     /* Set the threshold at which OP_Once counters reset back to zero.
3829     ** By default this is 0x7ffffffe (over 2 billion), but that value is
3830     ** too big to test in a reasonable amount of time, so this control is
3831     ** provided to set a small and easily reachable reset value.
3832     */
3833     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
3834       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
3835       break;
3836     }
3837 
3838     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3839     **
3840     ** Set the VDBE coverage callback function to xCallback with context
3841     ** pointer ptr.
3842     */
3843     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3844 #ifdef SQLITE_VDBE_COVERAGE
3845       typedef void (*branch_callback)(void*,int,u8,u8);
3846       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3847       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3848 #endif
3849       break;
3850     }
3851 
3852     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3853     case SQLITE_TESTCTRL_SORTER_MMAP: {
3854       sqlite3 *db = va_arg(ap, sqlite3*);
3855       db->nMaxSorterMmap = va_arg(ap, int);
3856       break;
3857     }
3858 
3859     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3860     **
3861     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3862     ** not.
3863     */
3864     case SQLITE_TESTCTRL_ISINIT: {
3865       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3866       break;
3867     }
3868 
3869     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3870     **
3871     ** This test control is used to create imposter tables.  "db" is a pointer
3872     ** to the database connection.  dbName is the database name (ex: "main" or
3873     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3874     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3875     ** table should connect.
3876     **
3877     ** Enable imposter mode only when the schema has already been parsed.  Then
3878     ** run a single CREATE TABLE statement to construct the imposter table in
3879     ** the parsed schema.  Then turn imposter mode back off again.
3880     **
3881     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3882     ** the schema to be reparsed the next time it is needed.  This has the
3883     ** effect of erasing all imposter tables.
3884     */
3885     case SQLITE_TESTCTRL_IMPOSTER: {
3886       sqlite3 *db = va_arg(ap, sqlite3*);
3887       sqlite3_mutex_enter(db->mutex);
3888       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3889       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3890       db->init.newTnum = va_arg(ap,int);
3891       if( db->init.busy==0 && db->init.newTnum>0 ){
3892         sqlite3ResetAllSchemasOfConnection(db);
3893       }
3894       sqlite3_mutex_leave(db->mutex);
3895       break;
3896     }
3897   }
3898   va_end(ap);
3899 #endif /* SQLITE_UNTESTABLE */
3900   return rc;
3901 }
3902 
3903 /*
3904 ** This is a utility routine, useful to VFS implementations, that checks
3905 ** to see if a database file was a URI that contained a specific query
3906 ** parameter, and if so obtains the value of the query parameter.
3907 **
3908 ** The zFilename argument is the filename pointer passed into the xOpen()
3909 ** method of a VFS implementation.  The zParam argument is the name of the
3910 ** query parameter we seek.  This routine returns the value of the zParam
3911 ** parameter if it exists.  If the parameter does not exist, this routine
3912 ** returns a NULL pointer.
3913 */
3914 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3915   if( zFilename==0 || zParam==0 ) return 0;
3916   zFilename += sqlite3Strlen30(zFilename) + 1;
3917   while( zFilename[0] ){
3918     int x = strcmp(zFilename, zParam);
3919     zFilename += sqlite3Strlen30(zFilename) + 1;
3920     if( x==0 ) return zFilename;
3921     zFilename += sqlite3Strlen30(zFilename) + 1;
3922   }
3923   return 0;
3924 }
3925 
3926 /*
3927 ** Return a boolean value for a query parameter.
3928 */
3929 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3930   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3931   bDflt = bDflt!=0;
3932   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3933 }
3934 
3935 /*
3936 ** Return a 64-bit integer value for a query parameter.
3937 */
3938 sqlite3_int64 sqlite3_uri_int64(
3939   const char *zFilename,    /* Filename as passed to xOpen */
3940   const char *zParam,       /* URI parameter sought */
3941   sqlite3_int64 bDflt       /* return if parameter is missing */
3942 ){
3943   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3944   sqlite3_int64 v;
3945   if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
3946     bDflt = v;
3947   }
3948   return bDflt;
3949 }
3950 
3951 /*
3952 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3953 */
3954 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3955   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
3956   return iDb<0 ? 0 : db->aDb[iDb].pBt;
3957 }
3958 
3959 /*
3960 ** Return the filename of the database associated with a database
3961 ** connection.
3962 */
3963 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3964   Btree *pBt;
3965 #ifdef SQLITE_ENABLE_API_ARMOR
3966   if( !sqlite3SafetyCheckOk(db) ){
3967     (void)SQLITE_MISUSE_BKPT;
3968     return 0;
3969   }
3970 #endif
3971   pBt = sqlite3DbNameToBtree(db, zDbName);
3972   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3973 }
3974 
3975 /*
3976 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3977 ** no such database exists.
3978 */
3979 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3980   Btree *pBt;
3981 #ifdef SQLITE_ENABLE_API_ARMOR
3982   if( !sqlite3SafetyCheckOk(db) ){
3983     (void)SQLITE_MISUSE_BKPT;
3984     return -1;
3985   }
3986 #endif
3987   pBt = sqlite3DbNameToBtree(db, zDbName);
3988   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3989 }
3990 
3991 #ifdef SQLITE_ENABLE_SNAPSHOT
3992 /*
3993 ** Obtain a snapshot handle for the snapshot of database zDb currently
3994 ** being read by handle db.
3995 */
3996 int sqlite3_snapshot_get(
3997   sqlite3 *db,
3998   const char *zDb,
3999   sqlite3_snapshot **ppSnapshot
4000 ){
4001   int rc = SQLITE_ERROR;
4002 #ifndef SQLITE_OMIT_WAL
4003 
4004 #ifdef SQLITE_ENABLE_API_ARMOR
4005   if( !sqlite3SafetyCheckOk(db) ){
4006     return SQLITE_MISUSE_BKPT;
4007   }
4008 #endif
4009   sqlite3_mutex_enter(db->mutex);
4010 
4011   if( db->autoCommit==0 ){
4012     int iDb = sqlite3FindDbName(db, zDb);
4013     if( iDb==0 || iDb>1 ){
4014       Btree *pBt = db->aDb[iDb].pBt;
4015       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4016         rc = sqlite3BtreeBeginTrans(pBt, 0);
4017         if( rc==SQLITE_OK ){
4018           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4019         }
4020       }
4021     }
4022   }
4023 
4024   sqlite3_mutex_leave(db->mutex);
4025 #endif   /* SQLITE_OMIT_WAL */
4026   return rc;
4027 }
4028 
4029 /*
4030 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4031 */
4032 int sqlite3_snapshot_open(
4033   sqlite3 *db,
4034   const char *zDb,
4035   sqlite3_snapshot *pSnapshot
4036 ){
4037   int rc = SQLITE_ERROR;
4038 #ifndef SQLITE_OMIT_WAL
4039 
4040 #ifdef SQLITE_ENABLE_API_ARMOR
4041   if( !sqlite3SafetyCheckOk(db) ){
4042     return SQLITE_MISUSE_BKPT;
4043   }
4044 #endif
4045   sqlite3_mutex_enter(db->mutex);
4046   if( db->autoCommit==0 ){
4047     int iDb;
4048     iDb = sqlite3FindDbName(db, zDb);
4049     if( iDb==0 || iDb>1 ){
4050       Btree *pBt = db->aDb[iDb].pBt;
4051       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4052         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
4053         if( rc==SQLITE_OK ){
4054           rc = sqlite3BtreeBeginTrans(pBt, 0);
4055           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
4056         }
4057       }
4058     }
4059   }
4060 
4061   sqlite3_mutex_leave(db->mutex);
4062 #endif   /* SQLITE_OMIT_WAL */
4063   return rc;
4064 }
4065 
4066 /*
4067 ** Recover as many snapshots as possible from the wal file associated with
4068 ** schema zDb of database db.
4069 */
4070 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4071   int rc = SQLITE_ERROR;
4072   int iDb;
4073 #ifndef SQLITE_OMIT_WAL
4074 
4075 #ifdef SQLITE_ENABLE_API_ARMOR
4076   if( !sqlite3SafetyCheckOk(db) ){
4077     return SQLITE_MISUSE_BKPT;
4078   }
4079 #endif
4080 
4081   sqlite3_mutex_enter(db->mutex);
4082   iDb = sqlite3FindDbName(db, zDb);
4083   if( iDb==0 || iDb>1 ){
4084     Btree *pBt = db->aDb[iDb].pBt;
4085     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4086       rc = sqlite3BtreeBeginTrans(pBt, 0);
4087       if( rc==SQLITE_OK ){
4088         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4089         sqlite3BtreeCommit(pBt);
4090       }
4091     }
4092   }
4093   sqlite3_mutex_leave(db->mutex);
4094 #endif   /* SQLITE_OMIT_WAL */
4095   return rc;
4096 }
4097 
4098 /*
4099 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4100 */
4101 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4102   sqlite3_free(pSnapshot);
4103 }
4104 #endif /* SQLITE_ENABLE_SNAPSHOT */
4105 
4106 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4107 /*
4108 ** Given the name of a compile-time option, return true if that option
4109 ** was used and false if not.
4110 **
4111 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4112 ** is not required for a match.
4113 */
4114 int sqlite3_compileoption_used(const char *zOptName){
4115   int i, n;
4116   int nOpt;
4117   const char **azCompileOpt;
4118 
4119 #if SQLITE_ENABLE_API_ARMOR
4120   if( zOptName==0 ){
4121     (void)SQLITE_MISUSE_BKPT;
4122     return 0;
4123   }
4124 #endif
4125 
4126   azCompileOpt = sqlite3CompileOptions(&nOpt);
4127 
4128   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4129   n = sqlite3Strlen30(zOptName);
4130 
4131   /* Since nOpt is normally in single digits, a linear search is
4132   ** adequate. No need for a binary search. */
4133   for(i=0; i<nOpt; i++){
4134     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4135      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4136     ){
4137       return 1;
4138     }
4139   }
4140   return 0;
4141 }
4142 
4143 /*
4144 ** Return the N-th compile-time option string.  If N is out of range,
4145 ** return a NULL pointer.
4146 */
4147 const char *sqlite3_compileoption_get(int N){
4148   int nOpt;
4149   const char **azCompileOpt;
4150   azCompileOpt = sqlite3CompileOptions(&nOpt);
4151   if( N>=0 && N<nOpt ){
4152     return azCompileOpt[N];
4153   }
4154   return 0;
4155 }
4156 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4157