xref: /sqlite-3.40.0/src/main.c (revision 7ac2ee0a)
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 #if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
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-25063-23286 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. Except if SQLite is built using
53 ** an edited copy of the amalgamation, then the last four characters of
54 ** the hash might be different from SQLITE_SOURCE_ID.
55 */
56 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
57 
58 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
59 ** returns an integer equal to SQLITE_VERSION_NUMBER.
60 */
61 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
62 
63 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
64 ** zero if and only if SQLite was compiled with mutexing code omitted due to
65 ** the SQLITE_THREADSAFE compile-time option being set to 0.
66 */
67 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
68 
69 /*
70 ** When compiling the test fixture or with debugging enabled (on Win32),
71 ** this variable being set to non-zero will cause OSTRACE macros to emit
72 ** extra diagnostic information.
73 */
74 #ifdef SQLITE_HAVE_OS_TRACE
75 # ifndef SQLITE_DEBUG_OS_TRACE
76 #   define SQLITE_DEBUG_OS_TRACE 0
77 # endif
78   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
79 #endif
80 
81 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
82 /*
83 ** If the following function pointer is not NULL and if
84 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
85 ** I/O active are written using this function.  These messages
86 ** are intended for debugging activity only.
87 */
88 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
89 #endif
90 
91 /*
92 ** If the following global variable points to a string which is the
93 ** name of a directory, then that directory will be used to store
94 ** temporary files.
95 **
96 ** See also the "PRAGMA temp_store_directory" SQL command.
97 */
98 char *sqlite3_temp_directory = 0;
99 
100 /*
101 ** If the following global variable points to a string which is the
102 ** name of a directory, then that directory will be used to store
103 ** all database files specified with a relative pathname.
104 **
105 ** See also the "PRAGMA data_store_directory" SQL command.
106 */
107 char *sqlite3_data_directory = 0;
108 
109 /*
110 ** Initialize SQLite.
111 **
112 ** This routine must be called to initialize the memory allocation,
113 ** VFS, and mutex subsystems prior to doing any serious work with
114 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
115 ** this routine will be called automatically by key routines such as
116 ** sqlite3_open().
117 **
118 ** This routine is a no-op except on its very first call for the process,
119 ** or for the first call after a call to sqlite3_shutdown.
120 **
121 ** The first thread to call this routine runs the initialization to
122 ** completion.  If subsequent threads call this routine before the first
123 ** thread has finished the initialization process, then the subsequent
124 ** threads must block until the first thread finishes with the initialization.
125 **
126 ** The first thread might call this routine recursively.  Recursive
127 ** calls to this routine should not block, of course.  Otherwise the
128 ** initialization process would never complete.
129 **
130 ** Let X be the first thread to enter this routine.  Let Y be some other
131 ** thread.  Then while the initial invocation of this routine by X is
132 ** incomplete, it is required that:
133 **
134 **    *  Calls to this routine from Y must block until the outer-most
135 **       call by X completes.
136 **
137 **    *  Recursive calls to this routine from thread X return immediately
138 **       without blocking.
139 */
140 int sqlite3_initialize(void){
141   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
142   int rc;                                      /* Result code */
143 #ifdef SQLITE_EXTRA_INIT
144   int bRunExtraInit = 0;                       /* Extra initialization needed */
145 #endif
146 
147 #ifdef SQLITE_OMIT_WSD
148   rc = sqlite3_wsd_init(4096, 24);
149   if( rc!=SQLITE_OK ){
150     return rc;
151   }
152 #endif
153 
154   /* If the following assert() fails on some obscure processor/compiler
155   ** combination, the work-around is to set the correct pointer
156   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
157   assert( SQLITE_PTRSIZE==sizeof(char*) );
158 
159   /* If SQLite is already completely initialized, then this call
160   ** to sqlite3_initialize() should be a no-op.  But the initialization
161   ** must be complete.  So isInit must not be set until the very end
162   ** of this routine.
163   */
164   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
165 
166   /* Make sure the mutex subsystem is initialized.  If unable to
167   ** initialize the mutex subsystem, return early with the error.
168   ** If the system is so sick that we are unable to allocate a mutex,
169   ** there is not much SQLite is going to be able to do.
170   **
171   ** The mutex subsystem must take care of serializing its own
172   ** initialization.
173   */
174   rc = sqlite3MutexInit();
175   if( rc ) return rc;
176 
177   /* Initialize the malloc() system and the recursive pInitMutex mutex.
178   ** This operation is protected by the STATIC_MASTER mutex.  Note that
179   ** MutexAlloc() is called for a static mutex prior to initializing the
180   ** malloc subsystem - this implies that the allocation of a static
181   ** mutex must not require support from the malloc subsystem.
182   */
183   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
184   sqlite3_mutex_enter(pMaster);
185   sqlite3GlobalConfig.isMutexInit = 1;
186   if( !sqlite3GlobalConfig.isMallocInit ){
187     rc = sqlite3MallocInit();
188   }
189   if( rc==SQLITE_OK ){
190     sqlite3GlobalConfig.isMallocInit = 1;
191     if( !sqlite3GlobalConfig.pInitMutex ){
192       sqlite3GlobalConfig.pInitMutex =
193            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
194       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
195         rc = SQLITE_NOMEM_BKPT;
196       }
197     }
198   }
199   if( rc==SQLITE_OK ){
200     sqlite3GlobalConfig.nRefInitMutex++;
201   }
202   sqlite3_mutex_leave(pMaster);
203 
204   /* If rc is not SQLITE_OK at this point, then either the malloc
205   ** subsystem could not be initialized or the system failed to allocate
206   ** the pInitMutex mutex. Return an error in either case.  */
207   if( rc!=SQLITE_OK ){
208     return rc;
209   }
210 
211   /* Do the rest of the initialization under the recursive mutex so
212   ** that we will be able to handle recursive calls into
213   ** sqlite3_initialize().  The recursive calls normally come through
214   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
215   ** recursive calls might also be possible.
216   **
217   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
218   ** to the xInit method, so the xInit method need not be threadsafe.
219   **
220   ** The following mutex is what serializes access to the appdef pcache xInit
221   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
222   ** call to sqlite3PcacheInitialize().
223   */
224   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
225   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
226     sqlite3GlobalConfig.inProgress = 1;
227 #ifdef SQLITE_ENABLE_SQLLOG
228     {
229       extern void sqlite3_init_sqllog(void);
230       sqlite3_init_sqllog();
231     }
232 #endif
233     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
234     sqlite3RegisterBuiltinFunctions();
235     if( sqlite3GlobalConfig.isPCacheInit==0 ){
236       rc = sqlite3PcacheInitialize();
237     }
238     if( rc==SQLITE_OK ){
239       sqlite3GlobalConfig.isPCacheInit = 1;
240       rc = sqlite3OsInit();
241     }
242 #ifdef SQLITE_ENABLE_DESERIALIZE
243     if( rc==SQLITE_OK ){
244       rc = sqlite3MemdbInit();
245     }
246 #endif
247     if( rc==SQLITE_OK ){
248       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
249           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
250       sqlite3GlobalConfig.isInit = 1;
251 #ifdef SQLITE_EXTRA_INIT
252       bRunExtraInit = 1;
253 #endif
254     }
255     sqlite3GlobalConfig.inProgress = 0;
256   }
257   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
258 
259   /* Go back under the static mutex and clean up the recursive
260   ** mutex to prevent a resource leak.
261   */
262   sqlite3_mutex_enter(pMaster);
263   sqlite3GlobalConfig.nRefInitMutex--;
264   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
265     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
266     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
267     sqlite3GlobalConfig.pInitMutex = 0;
268   }
269   sqlite3_mutex_leave(pMaster);
270 
271   /* The following is just a sanity check to make sure SQLite has
272   ** been compiled correctly.  It is important to run this code, but
273   ** we don't want to run it too often and soak up CPU cycles for no
274   ** reason.  So we run it once during initialization.
275   */
276 #ifndef NDEBUG
277 #ifndef SQLITE_OMIT_FLOATING_POINT
278   /* This section of code's only "output" is via assert() statements. */
279   if( rc==SQLITE_OK ){
280     u64 x = (((u64)1)<<63)-1;
281     double y;
282     assert(sizeof(x)==8);
283     assert(sizeof(x)==sizeof(y));
284     memcpy(&y, &x, 8);
285     assert( sqlite3IsNaN(y) );
286   }
287 #endif
288 #endif
289 
290   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
291   ** compile-time option.
292   */
293 #ifdef SQLITE_EXTRA_INIT
294   if( bRunExtraInit ){
295     int SQLITE_EXTRA_INIT(const char*);
296     rc = SQLITE_EXTRA_INIT(0);
297   }
298 #endif
299 
300   return rc;
301 }
302 
303 /*
304 ** Undo the effects of sqlite3_initialize().  Must not be called while
305 ** there are outstanding database connections or memory allocations or
306 ** while any part of SQLite is otherwise in use in any thread.  This
307 ** routine is not threadsafe.  But it is safe to invoke this routine
308 ** on when SQLite is already shut down.  If SQLite is already shut down
309 ** when this routine is invoked, then this routine is a harmless no-op.
310 */
311 int sqlite3_shutdown(void){
312 #ifdef SQLITE_OMIT_WSD
313   int rc = sqlite3_wsd_init(4096, 24);
314   if( rc!=SQLITE_OK ){
315     return rc;
316   }
317 #endif
318 
319   if( sqlite3GlobalConfig.isInit ){
320 #ifdef SQLITE_EXTRA_SHUTDOWN
321     void SQLITE_EXTRA_SHUTDOWN(void);
322     SQLITE_EXTRA_SHUTDOWN();
323 #endif
324     sqlite3_os_end();
325     sqlite3_reset_auto_extension();
326     sqlite3GlobalConfig.isInit = 0;
327   }
328   if( sqlite3GlobalConfig.isPCacheInit ){
329     sqlite3PcacheShutdown();
330     sqlite3GlobalConfig.isPCacheInit = 0;
331   }
332   if( sqlite3GlobalConfig.isMallocInit ){
333     sqlite3MallocEnd();
334     sqlite3GlobalConfig.isMallocInit = 0;
335 
336 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
337     /* The heap subsystem has now been shutdown and these values are supposed
338     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
339     ** which would rely on that heap subsystem; therefore, make sure these
340     ** values cannot refer to heap memory that was just invalidated when the
341     ** heap subsystem was shutdown.  This is only done if the current call to
342     ** this function resulted in the heap subsystem actually being shutdown.
343     */
344     sqlite3_data_directory = 0;
345     sqlite3_temp_directory = 0;
346 #endif
347   }
348   if( sqlite3GlobalConfig.isMutexInit ){
349     sqlite3MutexEnd();
350     sqlite3GlobalConfig.isMutexInit = 0;
351   }
352 
353   return SQLITE_OK;
354 }
355 
356 /*
357 ** This API allows applications to modify the global configuration of
358 ** the SQLite library at run-time.
359 **
360 ** This routine should only be called when there are no outstanding
361 ** database connections or memory allocations.  This routine is not
362 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
363 ** behavior.
364 */
365 int sqlite3_config(int op, ...){
366   va_list ap;
367   int rc = SQLITE_OK;
368 
369   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
370   ** the SQLite library is in use. */
371   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
372 
373   va_start(ap, op);
374   switch( op ){
375 
376     /* Mutex configuration options are only available in a threadsafe
377     ** compile.
378     */
379 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
380     case SQLITE_CONFIG_SINGLETHREAD: {
381       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
382       ** Single-thread. */
383       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
384       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
385       break;
386     }
387 #endif
388 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
389     case SQLITE_CONFIG_MULTITHREAD: {
390       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
391       ** Multi-thread. */
392       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
393       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
394       break;
395     }
396 #endif
397 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
398     case SQLITE_CONFIG_SERIALIZED: {
399       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
400       ** Serialized. */
401       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
402       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
403       break;
404     }
405 #endif
406 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
407     case SQLITE_CONFIG_MUTEX: {
408       /* Specify an alternative mutex implementation */
409       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
410       break;
411     }
412 #endif
413 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
414     case SQLITE_CONFIG_GETMUTEX: {
415       /* Retrieve the current mutex implementation */
416       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
417       break;
418     }
419 #endif
420 
421     case SQLITE_CONFIG_MALLOC: {
422       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
423       ** single argument which is a pointer to an instance of the
424       ** sqlite3_mem_methods structure. The argument specifies alternative
425       ** low-level memory allocation routines to be used in place of the memory
426       ** allocation routines built into SQLite. */
427       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
428       break;
429     }
430     case SQLITE_CONFIG_GETMALLOC: {
431       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
432       ** single argument which is a pointer to an instance of the
433       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
434       ** filled with the currently defined memory allocation routines. */
435       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
436       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
437       break;
438     }
439     case SQLITE_CONFIG_MEMSTATUS: {
440       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
441       ** single argument of type int, interpreted as a boolean, which enables
442       ** or disables the collection of memory allocation statistics. */
443       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
444       break;
445     }
446     case SQLITE_CONFIG_SMALL_MALLOC: {
447       sqlite3GlobalConfig.bSmallMalloc = va_arg(ap, int);
448       break;
449     }
450     case SQLITE_CONFIG_PAGECACHE: {
451       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
452       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
453       ** the size of each page cache line (sz), and the number of cache lines
454       ** (N). */
455       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
456       sqlite3GlobalConfig.szPage = va_arg(ap, int);
457       sqlite3GlobalConfig.nPage = va_arg(ap, int);
458       break;
459     }
460     case SQLITE_CONFIG_PCACHE_HDRSZ: {
461       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
462       ** a single parameter which is a pointer to an integer and writes into
463       ** that integer the number of extra bytes per page required for each page
464       ** in SQLITE_CONFIG_PAGECACHE. */
465       *va_arg(ap, int*) =
466           sqlite3HeaderSizeBtree() +
467           sqlite3HeaderSizePcache() +
468           sqlite3HeaderSizePcache1();
469       break;
470     }
471 
472     case SQLITE_CONFIG_PCACHE: {
473       /* no-op */
474       break;
475     }
476     case SQLITE_CONFIG_GETPCACHE: {
477       /* now an error */
478       rc = SQLITE_ERROR;
479       break;
480     }
481 
482     case SQLITE_CONFIG_PCACHE2: {
483       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
484       ** single argument which is a pointer to an sqlite3_pcache_methods2
485       ** object. This object specifies the interface to a custom page cache
486       ** implementation. */
487       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
488       break;
489     }
490     case SQLITE_CONFIG_GETPCACHE2: {
491       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
492       ** single argument which is a pointer to an sqlite3_pcache_methods2
493       ** object. SQLite copies of the current page cache implementation into
494       ** that object. */
495       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
496         sqlite3PCacheSetDefault();
497       }
498       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
499       break;
500     }
501 
502 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
503 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
504 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
505 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
506     case SQLITE_CONFIG_HEAP: {
507       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
508       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
509       ** number of bytes in the memory buffer, and the minimum allocation size.
510       */
511       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
512       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
513       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
514 
515       if( sqlite3GlobalConfig.mnReq<1 ){
516         sqlite3GlobalConfig.mnReq = 1;
517       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
518         /* cap min request size at 2^12 */
519         sqlite3GlobalConfig.mnReq = (1<<12);
520       }
521 
522       if( sqlite3GlobalConfig.pHeap==0 ){
523         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
524         ** is NULL, then SQLite reverts to using its default memory allocator
525         ** (the system malloc() implementation), undoing any prior invocation of
526         ** SQLITE_CONFIG_MALLOC.
527         **
528         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
529         ** revert to its default implementation when sqlite3_initialize() is run
530         */
531         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
532       }else{
533         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
534         ** alternative memory allocator is engaged to handle all of SQLites
535         ** memory allocation needs. */
536 #ifdef SQLITE_ENABLE_MEMSYS3
537         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
538 #endif
539 #ifdef SQLITE_ENABLE_MEMSYS5
540         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
541 #endif
542       }
543       break;
544     }
545 #endif
546 
547     case SQLITE_CONFIG_LOOKASIDE: {
548       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
549       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
550       break;
551     }
552 
553     /* Record a pointer to the logger function and its first argument.
554     ** The default is NULL.  Logging is disabled if the function pointer is
555     ** NULL.
556     */
557     case SQLITE_CONFIG_LOG: {
558       /* MSVC is picky about pulling func ptrs from va lists.
559       ** http://support.microsoft.com/kb/47961
560       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
561       */
562       typedef void(*LOGFUNC_t)(void*,int,const char*);
563       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
564       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
565       break;
566     }
567 
568     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
569     ** can be changed at start-time using the
570     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
571     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
572     */
573     case SQLITE_CONFIG_URI: {
574       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
575       ** argument of type int. If non-zero, then URI handling is globally
576       ** enabled. If the parameter is zero, then URI handling is globally
577       ** disabled. */
578       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
579       break;
580     }
581 
582     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
583       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
584       ** option takes a single integer argument which is interpreted as a
585       ** boolean in order to enable or disable the use of covering indices for
586       ** full table scans in the query optimizer. */
587       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
588       break;
589     }
590 
591 #ifdef SQLITE_ENABLE_SQLLOG
592     case SQLITE_CONFIG_SQLLOG: {
593       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
594       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
595       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
596       break;
597     }
598 #endif
599 
600     case SQLITE_CONFIG_MMAP_SIZE: {
601       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
602       ** integer (sqlite3_int64) values that are the default mmap size limit
603       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
604       ** mmap size limit. */
605       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
606       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
607       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
608       ** negative, then that argument is changed to its compile-time default.
609       **
610       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
611       ** silently truncated if necessary so that it does not exceed the
612       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
613       ** compile-time option.
614       */
615       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
616         mxMmap = SQLITE_MAX_MMAP_SIZE;
617       }
618       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
619       if( szMmap>mxMmap) szMmap = mxMmap;
620       sqlite3GlobalConfig.mxMmap = mxMmap;
621       sqlite3GlobalConfig.szMmap = szMmap;
622       break;
623     }
624 
625 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
626     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
627       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
628       ** unsigned integer value that specifies the maximum size of the created
629       ** heap. */
630       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
631       break;
632     }
633 #endif
634 
635     case SQLITE_CONFIG_PMASZ: {
636       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
637       break;
638     }
639 
640     case SQLITE_CONFIG_STMTJRNL_SPILL: {
641       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
642       break;
643     }
644 
645 #ifdef SQLITE_ENABLE_SORTER_REFERENCES
646     case SQLITE_CONFIG_SORTERREF_SIZE: {
647       int iVal = va_arg(ap, int);
648       if( iVal<0 ){
649         iVal = SQLITE_DEFAULT_SORTERREF_SIZE;
650       }
651       sqlite3GlobalConfig.szSorterRef = (u32)iVal;
652       break;
653     }
654 #endif /* SQLITE_ENABLE_SORTER_REFERENCES */
655 
656 #ifdef SQLITE_ENABLE_DESERIALIZE
657     case SQLITE_CONFIG_MEMDB_MAXSIZE: {
658       sqlite3GlobalConfig.mxMemdbSize = va_arg(ap, sqlite3_int64);
659       break;
660     }
661 #endif /* SQLITE_ENABLE_DESERIALIZE */
662 
663     default: {
664       rc = SQLITE_ERROR;
665       break;
666     }
667   }
668   va_end(ap);
669   return rc;
670 }
671 
672 /*
673 ** Set up the lookaside buffers for a database connection.
674 ** Return SQLITE_OK on success.
675 ** If lookaside is already active, return SQLITE_BUSY.
676 **
677 ** The sz parameter is the number of bytes in each lookaside slot.
678 ** The cnt parameter is the number of slots.  If pStart is NULL the
679 ** space for the lookaside memory is obtained from sqlite3_malloc().
680 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
681 ** the lookaside memory.
682 */
683 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
684 #ifndef SQLITE_OMIT_LOOKASIDE
685   void *pStart;
686 
687   if( sqlite3LookasideUsed(db,0)>0 ){
688     return SQLITE_BUSY;
689   }
690   /* Free any existing lookaside buffer for this handle before
691   ** allocating a new one so we don't have to have space for
692   ** both at the same time.
693   */
694   if( db->lookaside.bMalloced ){
695     sqlite3_free(db->lookaside.pStart);
696   }
697   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
698   ** than a pointer to be useful.
699   */
700   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
701   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
702   if( cnt<0 ) cnt = 0;
703   if( sz==0 || cnt==0 ){
704     sz = 0;
705     pStart = 0;
706   }else if( pBuf==0 ){
707     sqlite3BeginBenignMalloc();
708     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
709     sqlite3EndBenignMalloc();
710     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
711   }else{
712     pStart = pBuf;
713   }
714   db->lookaside.pStart = pStart;
715   db->lookaside.pInit = 0;
716   db->lookaside.pFree = 0;
717   db->lookaside.sz = (u16)sz;
718   if( pStart ){
719     int i;
720     LookasideSlot *p;
721     assert( sz > (int)sizeof(LookasideSlot*) );
722     db->lookaside.nSlot = cnt;
723     p = (LookasideSlot*)pStart;
724     for(i=cnt-1; i>=0; i--){
725       p->pNext = db->lookaside.pInit;
726       db->lookaside.pInit = p;
727       p = (LookasideSlot*)&((u8*)p)[sz];
728     }
729     db->lookaside.pEnd = p;
730     db->lookaside.bDisable = 0;
731     db->lookaside.bMalloced = pBuf==0 ?1:0;
732   }else{
733     db->lookaside.pStart = db;
734     db->lookaside.pEnd = db;
735     db->lookaside.bDisable = 1;
736     db->lookaside.bMalloced = 0;
737     db->lookaside.nSlot = 0;
738   }
739 #endif /* SQLITE_OMIT_LOOKASIDE */
740   return SQLITE_OK;
741 }
742 
743 /*
744 ** Return the mutex associated with a database connection.
745 */
746 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
747 #ifdef SQLITE_ENABLE_API_ARMOR
748   if( !sqlite3SafetyCheckOk(db) ){
749     (void)SQLITE_MISUSE_BKPT;
750     return 0;
751   }
752 #endif
753   return db->mutex;
754 }
755 
756 /*
757 ** Free up as much memory as we can from the given database
758 ** connection.
759 */
760 int sqlite3_db_release_memory(sqlite3 *db){
761   int i;
762 
763 #ifdef SQLITE_ENABLE_API_ARMOR
764   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
765 #endif
766   sqlite3_mutex_enter(db->mutex);
767   sqlite3BtreeEnterAll(db);
768   for(i=0; i<db->nDb; i++){
769     Btree *pBt = db->aDb[i].pBt;
770     if( pBt ){
771       Pager *pPager = sqlite3BtreePager(pBt);
772       sqlite3PagerShrink(pPager);
773     }
774   }
775   sqlite3BtreeLeaveAll(db);
776   sqlite3_mutex_leave(db->mutex);
777   return SQLITE_OK;
778 }
779 
780 /*
781 ** Flush any dirty pages in the pager-cache for any attached database
782 ** to disk.
783 */
784 int sqlite3_db_cacheflush(sqlite3 *db){
785   int i;
786   int rc = SQLITE_OK;
787   int bSeenBusy = 0;
788 
789 #ifdef SQLITE_ENABLE_API_ARMOR
790   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
791 #endif
792   sqlite3_mutex_enter(db->mutex);
793   sqlite3BtreeEnterAll(db);
794   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
795     Btree *pBt = db->aDb[i].pBt;
796     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
797       Pager *pPager = sqlite3BtreePager(pBt);
798       rc = sqlite3PagerFlush(pPager);
799       if( rc==SQLITE_BUSY ){
800         bSeenBusy = 1;
801         rc = SQLITE_OK;
802       }
803     }
804   }
805   sqlite3BtreeLeaveAll(db);
806   sqlite3_mutex_leave(db->mutex);
807   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
808 }
809 
810 /*
811 ** Configuration settings for an individual database connection
812 */
813 int sqlite3_db_config(sqlite3 *db, int op, ...){
814   va_list ap;
815   int rc;
816   va_start(ap, op);
817   switch( op ){
818     case SQLITE_DBCONFIG_MAINDBNAME: {
819       /* IMP: R-06824-28531 */
820       /* IMP: R-36257-52125 */
821       db->aDb[0].zDbSName = va_arg(ap,char*);
822       rc = SQLITE_OK;
823       break;
824     }
825     case SQLITE_DBCONFIG_LOOKASIDE: {
826       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
827       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
828       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
829       rc = setupLookaside(db, pBuf, sz, cnt);
830       break;
831     }
832     default: {
833       static const struct {
834         int op;      /* The opcode */
835         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
836       } aFlagOp[] = {
837         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
838         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
839         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
840         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
841         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
842         { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
843         { SQLITE_DBCONFIG_TRIGGER_EQP,           SQLITE_TriggerEQP     },
844         { SQLITE_DBCONFIG_RESET_DATABASE,        SQLITE_ResetDatabase  },
845         { SQLITE_DBCONFIG_DEFENSIVE,             SQLITE_Defensive      },
846       };
847       unsigned int i;
848       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
849       for(i=0; i<ArraySize(aFlagOp); i++){
850         if( aFlagOp[i].op==op ){
851           int onoff = va_arg(ap, int);
852           int *pRes = va_arg(ap, int*);
853           u64 oldFlags = db->flags;
854           if( onoff>0 ){
855             db->flags |= aFlagOp[i].mask;
856           }else if( onoff==0 ){
857             db->flags &= ~(u64)aFlagOp[i].mask;
858           }
859           if( oldFlags!=db->flags ){
860             sqlite3ExpirePreparedStatements(db, 0);
861           }
862           if( pRes ){
863             *pRes = (db->flags & aFlagOp[i].mask)!=0;
864           }
865           rc = SQLITE_OK;
866           break;
867         }
868       }
869       break;
870     }
871   }
872   va_end(ap);
873   return rc;
874 }
875 
876 
877 /*
878 ** Return true if the buffer z[0..n-1] contains all spaces.
879 */
880 static int allSpaces(const char *z, int n){
881   while( n>0 && z[n-1]==' ' ){ n--; }
882   return n==0;
883 }
884 
885 /*
886 ** This is the default collating function named "BINARY" which is always
887 ** available.
888 **
889 ** If the padFlag argument is not NULL then space padding at the end
890 ** of strings is ignored.  This implements the RTRIM collation.
891 */
892 static int binCollFunc(
893   void *padFlag,
894   int nKey1, const void *pKey1,
895   int nKey2, const void *pKey2
896 ){
897   int rc, n;
898   n = nKey1<nKey2 ? nKey1 : nKey2;
899   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
900   ** strings byte by byte using the memcmp() function from the standard C
901   ** library. */
902   assert( pKey1 && pKey2 );
903   rc = memcmp(pKey1, pKey2, n);
904   if( rc==0 ){
905     if( padFlag
906      && allSpaces(((char*)pKey1)+n, nKey1-n)
907      && allSpaces(((char*)pKey2)+n, nKey2-n)
908     ){
909       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
910       ** spaces at the end of either string do not change the result. In other
911       ** words, strings will compare equal to one another as long as they
912       ** differ only in the number of spaces at the end.
913       */
914     }else{
915       rc = nKey1 - nKey2;
916     }
917   }
918   return rc;
919 }
920 
921 /*
922 ** Return true if CollSeq is the default built-in BINARY.
923 */
924 int sqlite3IsBinary(const CollSeq *p){
925   assert( p==0 || p->xCmp!=binCollFunc || p->pUser!=0
926             || strcmp(p->zName,"BINARY")==0 );
927   return p==0 || (p->xCmp==binCollFunc && p->pUser==0);
928 }
929 
930 /*
931 ** Another built-in collating sequence: NOCASE.
932 **
933 ** This collating sequence is intended to be used for "case independent
934 ** comparison". SQLite's knowledge of upper and lower case equivalents
935 ** extends only to the 26 characters used in the English language.
936 **
937 ** At the moment there is only a UTF-8 implementation.
938 */
939 static int nocaseCollatingFunc(
940   void *NotUsed,
941   int nKey1, const void *pKey1,
942   int nKey2, const void *pKey2
943 ){
944   int r = sqlite3StrNICmp(
945       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
946   UNUSED_PARAMETER(NotUsed);
947   if( 0==r ){
948     r = nKey1-nKey2;
949   }
950   return r;
951 }
952 
953 /*
954 ** Return the ROWID of the most recent insert
955 */
956 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
957 #ifdef SQLITE_ENABLE_API_ARMOR
958   if( !sqlite3SafetyCheckOk(db) ){
959     (void)SQLITE_MISUSE_BKPT;
960     return 0;
961   }
962 #endif
963   return db->lastRowid;
964 }
965 
966 /*
967 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
968 */
969 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
970 #ifdef SQLITE_ENABLE_API_ARMOR
971   if( !sqlite3SafetyCheckOk(db) ){
972     (void)SQLITE_MISUSE_BKPT;
973     return;
974   }
975 #endif
976   sqlite3_mutex_enter(db->mutex);
977   db->lastRowid = iRowid;
978   sqlite3_mutex_leave(db->mutex);
979 }
980 
981 /*
982 ** Return the number of changes in the most recent call to sqlite3_exec().
983 */
984 int sqlite3_changes(sqlite3 *db){
985 #ifdef SQLITE_ENABLE_API_ARMOR
986   if( !sqlite3SafetyCheckOk(db) ){
987     (void)SQLITE_MISUSE_BKPT;
988     return 0;
989   }
990 #endif
991   return db->nChange;
992 }
993 
994 /*
995 ** Return the number of changes since the database handle was opened.
996 */
997 int sqlite3_total_changes(sqlite3 *db){
998 #ifdef SQLITE_ENABLE_API_ARMOR
999   if( !sqlite3SafetyCheckOk(db) ){
1000     (void)SQLITE_MISUSE_BKPT;
1001     return 0;
1002   }
1003 #endif
1004   return db->nTotalChange;
1005 }
1006 
1007 /*
1008 ** Close all open savepoints. This function only manipulates fields of the
1009 ** database handle object, it does not close any savepoints that may be open
1010 ** at the b-tree/pager level.
1011 */
1012 void sqlite3CloseSavepoints(sqlite3 *db){
1013   while( db->pSavepoint ){
1014     Savepoint *pTmp = db->pSavepoint;
1015     db->pSavepoint = pTmp->pNext;
1016     sqlite3DbFree(db, pTmp);
1017   }
1018   db->nSavepoint = 0;
1019   db->nStatement = 0;
1020   db->isTransactionSavepoint = 0;
1021 }
1022 
1023 /*
1024 ** Invoke the destructor function associated with FuncDef p, if any. Except,
1025 ** if this is not the last copy of the function, do not invoke it. Multiple
1026 ** copies of a single function are created when create_function() is called
1027 ** with SQLITE_ANY as the encoding.
1028 */
1029 static void functionDestroy(sqlite3 *db, FuncDef *p){
1030   FuncDestructor *pDestructor = p->u.pDestructor;
1031   if( pDestructor ){
1032     pDestructor->nRef--;
1033     if( pDestructor->nRef==0 ){
1034       pDestructor->xDestroy(pDestructor->pUserData);
1035       sqlite3DbFree(db, pDestructor);
1036     }
1037   }
1038 }
1039 
1040 /*
1041 ** Disconnect all sqlite3_vtab objects that belong to database connection
1042 ** db. This is called when db is being closed.
1043 */
1044 static void disconnectAllVtab(sqlite3 *db){
1045 #ifndef SQLITE_OMIT_VIRTUALTABLE
1046   int i;
1047   HashElem *p;
1048   sqlite3BtreeEnterAll(db);
1049   for(i=0; i<db->nDb; i++){
1050     Schema *pSchema = db->aDb[i].pSchema;
1051     if( pSchema ){
1052       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1053         Table *pTab = (Table *)sqliteHashData(p);
1054         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1055       }
1056     }
1057   }
1058   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1059     Module *pMod = (Module *)sqliteHashData(p);
1060     if( pMod->pEpoTab ){
1061       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1062     }
1063   }
1064   sqlite3VtabUnlockList(db);
1065   sqlite3BtreeLeaveAll(db);
1066 #else
1067   UNUSED_PARAMETER(db);
1068 #endif
1069 }
1070 
1071 /*
1072 ** Return TRUE if database connection db has unfinalized prepared
1073 ** statements or unfinished sqlite3_backup objects.
1074 */
1075 static int connectionIsBusy(sqlite3 *db){
1076   int j;
1077   assert( sqlite3_mutex_held(db->mutex) );
1078   if( db->pVdbe ) return 1;
1079   for(j=0; j<db->nDb; j++){
1080     Btree *pBt = db->aDb[j].pBt;
1081     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1082   }
1083   return 0;
1084 }
1085 
1086 /*
1087 ** Close an existing SQLite database
1088 */
1089 static int sqlite3Close(sqlite3 *db, int forceZombie){
1090   if( !db ){
1091     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1092     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1093     return SQLITE_OK;
1094   }
1095   if( !sqlite3SafetyCheckSickOrOk(db) ){
1096     return SQLITE_MISUSE_BKPT;
1097   }
1098   sqlite3_mutex_enter(db->mutex);
1099   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1100     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1101   }
1102 
1103   /* Force xDisconnect calls on all virtual tables */
1104   disconnectAllVtab(db);
1105 
1106   /* If a transaction is open, the disconnectAllVtab() call above
1107   ** will not have called the xDisconnect() method on any virtual
1108   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1109   ** call will do so. We need to do this before the check for active
1110   ** SQL statements below, as the v-table implementation may be storing
1111   ** some prepared statements internally.
1112   */
1113   sqlite3VtabRollback(db);
1114 
1115   /* Legacy behavior (sqlite3_close() behavior) is to return
1116   ** SQLITE_BUSY if the connection can not be closed immediately.
1117   */
1118   if( !forceZombie && connectionIsBusy(db) ){
1119     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1120        "statements or unfinished backups");
1121     sqlite3_mutex_leave(db->mutex);
1122     return SQLITE_BUSY;
1123   }
1124 
1125 #ifdef SQLITE_ENABLE_SQLLOG
1126   if( sqlite3GlobalConfig.xSqllog ){
1127     /* Closing the handle. Fourth parameter is passed the value 2. */
1128     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1129   }
1130 #endif
1131 
1132   /* Convert the connection into a zombie and then close it.
1133   */
1134   db->magic = SQLITE_MAGIC_ZOMBIE;
1135   sqlite3LeaveMutexAndCloseZombie(db);
1136   return SQLITE_OK;
1137 }
1138 
1139 /*
1140 ** Two variations on the public interface for closing a database
1141 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1142 ** leaves the connection option if there are unfinalized prepared
1143 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1144 ** version forces the connection to become a zombie if there are
1145 ** unclosed resources, and arranges for deallocation when the last
1146 ** prepare statement or sqlite3_backup closes.
1147 */
1148 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1149 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1150 
1151 
1152 /*
1153 ** Close the mutex on database connection db.
1154 **
1155 ** Furthermore, if database connection db is a zombie (meaning that there
1156 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1157 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1158 ** finished, then free all resources.
1159 */
1160 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1161   HashElem *i;                    /* Hash table iterator */
1162   int j;
1163 
1164   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1165   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1166   ** then just leave the mutex and return.
1167   */
1168   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1169     sqlite3_mutex_leave(db->mutex);
1170     return;
1171   }
1172 
1173   /* If we reach this point, it means that the database connection has
1174   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1175   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1176   ** go ahead and free all resources.
1177   */
1178 
1179   /* If a transaction is open, roll it back. This also ensures that if
1180   ** any database schemas have been modified by an uncommitted transaction
1181   ** they are reset. And that the required b-tree mutex is held to make
1182   ** the pager rollback and schema reset an atomic operation. */
1183   sqlite3RollbackAll(db, SQLITE_OK);
1184 
1185   /* Free any outstanding Savepoint structures. */
1186   sqlite3CloseSavepoints(db);
1187 
1188   /* Close all database connections */
1189   for(j=0; j<db->nDb; j++){
1190     struct Db *pDb = &db->aDb[j];
1191     if( pDb->pBt ){
1192       sqlite3BtreeClose(pDb->pBt);
1193       pDb->pBt = 0;
1194       if( j!=1 ){
1195         pDb->pSchema = 0;
1196       }
1197     }
1198   }
1199   /* Clear the TEMP schema separately and last */
1200   if( db->aDb[1].pSchema ){
1201     sqlite3SchemaClear(db->aDb[1].pSchema);
1202   }
1203   sqlite3VtabUnlockList(db);
1204 
1205   /* Free up the array of auxiliary databases */
1206   sqlite3CollapseDatabaseArray(db);
1207   assert( db->nDb<=2 );
1208   assert( db->aDb==db->aDbStatic );
1209 
1210   /* Tell the code in notify.c that the connection no longer holds any
1211   ** locks and does not require any further unlock-notify callbacks.
1212   */
1213   sqlite3ConnectionClosed(db);
1214 
1215   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1216     FuncDef *pNext, *p;
1217     p = sqliteHashData(i);
1218     do{
1219       functionDestroy(db, p);
1220       pNext = p->pNext;
1221       sqlite3DbFree(db, p);
1222       p = pNext;
1223     }while( p );
1224   }
1225   sqlite3HashClear(&db->aFunc);
1226   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1227     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1228     /* Invoke any destructors registered for collation sequence user data. */
1229     for(j=0; j<3; j++){
1230       if( pColl[j].xDel ){
1231         pColl[j].xDel(pColl[j].pUser);
1232       }
1233     }
1234     sqlite3DbFree(db, pColl);
1235   }
1236   sqlite3HashClear(&db->aCollSeq);
1237 #ifndef SQLITE_OMIT_VIRTUALTABLE
1238   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1239     Module *pMod = (Module *)sqliteHashData(i);
1240     if( pMod->xDestroy ){
1241       pMod->xDestroy(pMod->pAux);
1242     }
1243     sqlite3VtabEponymousTableClear(db, pMod);
1244     sqlite3DbFree(db, pMod);
1245   }
1246   sqlite3HashClear(&db->aModule);
1247 #endif
1248 
1249   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1250   sqlite3ValueFree(db->pErr);
1251   sqlite3CloseExtensions(db);
1252 #if SQLITE_USER_AUTHENTICATION
1253   sqlite3_free(db->auth.zAuthUser);
1254   sqlite3_free(db->auth.zAuthPW);
1255 #endif
1256 
1257   db->magic = SQLITE_MAGIC_ERROR;
1258 
1259   /* The temp-database schema is allocated differently from the other schema
1260   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1261   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1262   ** the same sqliteMalloc() as the one that allocates the database
1263   ** structure?
1264   */
1265   sqlite3DbFree(db, db->aDb[1].pSchema);
1266   sqlite3_mutex_leave(db->mutex);
1267   db->magic = SQLITE_MAGIC_CLOSED;
1268   sqlite3_mutex_free(db->mutex);
1269   assert( sqlite3LookasideUsed(db,0)==0 );
1270   if( db->lookaside.bMalloced ){
1271     sqlite3_free(db->lookaside.pStart);
1272   }
1273   sqlite3_free(db);
1274 }
1275 
1276 /*
1277 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1278 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1279 ** breaker") and made to return tripCode if there are any further
1280 ** attempts to use that cursor.  Read cursors remain open and valid
1281 ** but are "saved" in case the table pages are moved around.
1282 */
1283 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1284   int i;
1285   int inTrans = 0;
1286   int schemaChange;
1287   assert( sqlite3_mutex_held(db->mutex) );
1288   sqlite3BeginBenignMalloc();
1289 
1290   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1291   ** This is important in case the transaction being rolled back has
1292   ** modified the database schema. If the b-tree mutexes are not taken
1293   ** here, then another shared-cache connection might sneak in between
1294   ** the database rollback and schema reset, which can cause false
1295   ** corruption reports in some cases.  */
1296   sqlite3BtreeEnterAll(db);
1297   schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;
1298 
1299   for(i=0; i<db->nDb; i++){
1300     Btree *p = db->aDb[i].pBt;
1301     if( p ){
1302       if( sqlite3BtreeIsInTrans(p) ){
1303         inTrans = 1;
1304       }
1305       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1306     }
1307   }
1308   sqlite3VtabRollback(db);
1309   sqlite3EndBenignMalloc();
1310 
1311   if( schemaChange ){
1312     sqlite3ExpirePreparedStatements(db, 0);
1313     sqlite3ResetAllSchemasOfConnection(db);
1314   }
1315   sqlite3BtreeLeaveAll(db);
1316 
1317   /* Any deferred constraint violations have now been resolved. */
1318   db->nDeferredCons = 0;
1319   db->nDeferredImmCons = 0;
1320   db->flags &= ~(u64)SQLITE_DeferFKs;
1321 
1322   /* If one has been configured, invoke the rollback-hook callback */
1323   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1324     db->xRollbackCallback(db->pRollbackArg);
1325   }
1326 }
1327 
1328 /*
1329 ** Return a static string containing the name corresponding to the error code
1330 ** specified in the argument.
1331 */
1332 #if defined(SQLITE_NEED_ERR_NAME)
1333 const char *sqlite3ErrName(int rc){
1334   const char *zName = 0;
1335   int i, origRc = rc;
1336   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1337     switch( rc ){
1338       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1339       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1340       case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;
1341       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1342       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1343       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1344       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1345       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1346       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1347       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1348       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1349       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1350       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1351       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1352       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1353       case SQLITE_READONLY_CANTINIT:  zName = "SQLITE_READONLY_CANTINIT"; break;
1354       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1355       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1356       case SQLITE_READONLY_DIRECTORY: zName = "SQLITE_READONLY_DIRECTORY";break;
1357       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1358       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1359       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1360       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1361       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1362       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1363       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1364       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1365       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1366       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1367       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1368       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1369       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1370       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1371       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1372                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1373       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1374       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1375       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1376       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1377       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1378       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1379       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1380       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1381       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1382       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1383       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1384       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1385       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1386       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1387       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1388       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1389       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1390       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1391       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1392       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1393       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1394       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1395       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1396       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1397       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1398       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1399       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1400       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1401       case SQLITE_CONSTRAINT_FOREIGNKEY:
1402                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1403       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1404       case SQLITE_CONSTRAINT_PRIMARYKEY:
1405                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1406       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1407       case SQLITE_CONSTRAINT_COMMITHOOK:
1408                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1409       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1410       case SQLITE_CONSTRAINT_FUNCTION:
1411                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1412       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1413       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1414       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1415       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1416       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1417       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1418       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1419       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1420       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1421       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1422       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1423       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1424                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1425       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1426       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1427       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1428     }
1429   }
1430   if( zName==0 ){
1431     static char zBuf[50];
1432     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1433     zName = zBuf;
1434   }
1435   return zName;
1436 }
1437 #endif
1438 
1439 /*
1440 ** Return a static string that describes the kind of error specified in the
1441 ** argument.
1442 */
1443 const char *sqlite3ErrStr(int rc){
1444   static const char* const aMsg[] = {
1445     /* SQLITE_OK          */ "not an error",
1446     /* SQLITE_ERROR       */ "SQL logic error",
1447     /* SQLITE_INTERNAL    */ 0,
1448     /* SQLITE_PERM        */ "access permission denied",
1449     /* SQLITE_ABORT       */ "query aborted",
1450     /* SQLITE_BUSY        */ "database is locked",
1451     /* SQLITE_LOCKED      */ "database table is locked",
1452     /* SQLITE_NOMEM       */ "out of memory",
1453     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1454     /* SQLITE_INTERRUPT   */ "interrupted",
1455     /* SQLITE_IOERR       */ "disk I/O error",
1456     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1457     /* SQLITE_NOTFOUND    */ "unknown operation",
1458     /* SQLITE_FULL        */ "database or disk is full",
1459     /* SQLITE_CANTOPEN    */ "unable to open database file",
1460     /* SQLITE_PROTOCOL    */ "locking protocol",
1461     /* SQLITE_EMPTY       */ 0,
1462     /* SQLITE_SCHEMA      */ "database schema has changed",
1463     /* SQLITE_TOOBIG      */ "string or blob too big",
1464     /* SQLITE_CONSTRAINT  */ "constraint failed",
1465     /* SQLITE_MISMATCH    */ "datatype mismatch",
1466     /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
1467 #ifdef SQLITE_DISABLE_LFS
1468     /* SQLITE_NOLFS       */ "large file support is disabled",
1469 #else
1470     /* SQLITE_NOLFS       */ 0,
1471 #endif
1472     /* SQLITE_AUTH        */ "authorization denied",
1473     /* SQLITE_FORMAT      */ 0,
1474     /* SQLITE_RANGE       */ "column index out of range",
1475     /* SQLITE_NOTADB      */ "file is not a database",
1476     /* SQLITE_NOTICE      */ "notification message",
1477     /* SQLITE_WARNING     */ "warning message",
1478   };
1479   const char *zErr = "unknown error";
1480   switch( rc ){
1481     case SQLITE_ABORT_ROLLBACK: {
1482       zErr = "abort due to ROLLBACK";
1483       break;
1484     }
1485     case SQLITE_ROW: {
1486       zErr = "another row available";
1487       break;
1488     }
1489     case SQLITE_DONE: {
1490       zErr = "no more rows available";
1491       break;
1492     }
1493     default: {
1494       rc &= 0xff;
1495       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1496         zErr = aMsg[rc];
1497       }
1498       break;
1499     }
1500   }
1501   return zErr;
1502 }
1503 
1504 /*
1505 ** This routine implements a busy callback that sleeps and tries
1506 ** again until a timeout value is reached.  The timeout value is
1507 ** an integer number of milliseconds passed in as the first
1508 ** argument.
1509 **
1510 ** Return non-zero to retry the lock.  Return zero to stop trying
1511 ** and cause SQLite to return SQLITE_BUSY.
1512 */
1513 static int sqliteDefaultBusyCallback(
1514   void *ptr,               /* Database connection */
1515   int count,               /* Number of times table has been busy */
1516   sqlite3_file *pFile      /* The file on which the lock occurred */
1517 ){
1518 #if SQLITE_OS_WIN || HAVE_USLEEP
1519   /* This case is for systems that have support for sleeping for fractions of
1520   ** a second.  Examples:  All windows systems, unix systems with usleep() */
1521   static const u8 delays[] =
1522      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1523   static const u8 totals[] =
1524      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1525 # define NDELAY ArraySize(delays)
1526   sqlite3 *db = (sqlite3 *)ptr;
1527   int tmout = db->busyTimeout;
1528   int delay, prior;
1529 
1530 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
1531   if( sqlite3OsFileControl(pFile,SQLITE_FCNTL_LOCK_TIMEOUT,&tmout)==SQLITE_OK ){
1532     if( count ){
1533       tmout = 0;
1534       sqlite3OsFileControl(pFile, SQLITE_FCNTL_LOCK_TIMEOUT, &tmout);
1535       return 0;
1536     }else{
1537       return 1;
1538     }
1539   }
1540 #else
1541   UNUSED_PARAMETER(pFile);
1542 #endif
1543   assert( count>=0 );
1544   if( count < NDELAY ){
1545     delay = delays[count];
1546     prior = totals[count];
1547   }else{
1548     delay = delays[NDELAY-1];
1549     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1550   }
1551   if( prior + delay > tmout ){
1552     delay = tmout - prior;
1553     if( delay<=0 ) return 0;
1554   }
1555   sqlite3OsSleep(db->pVfs, delay*1000);
1556   return 1;
1557 #else
1558   /* This case for unix systems that lack usleep() support.  Sleeping
1559   ** must be done in increments of whole seconds */
1560   sqlite3 *db = (sqlite3 *)ptr;
1561   int tmout = ((sqlite3 *)ptr)->busyTimeout;
1562   UNUSED_PARAMETER(pFile);
1563   if( (count+1)*1000 > tmout ){
1564     return 0;
1565   }
1566   sqlite3OsSleep(db->pVfs, 1000000);
1567   return 1;
1568 #endif
1569 }
1570 
1571 /*
1572 ** Invoke the given busy handler.
1573 **
1574 ** This routine is called when an operation failed to acquire a
1575 ** lock on VFS file pFile.
1576 **
1577 ** If this routine returns non-zero, the lock is retried.  If it
1578 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1579 */
1580 int sqlite3InvokeBusyHandler(BusyHandler *p, sqlite3_file *pFile){
1581   int rc;
1582   if( p->xBusyHandler==0 || p->nBusy<0 ) return 0;
1583   if( p->bExtraFileArg ){
1584     /* Add an extra parameter with the pFile pointer to the end of the
1585     ** callback argument list */
1586     int (*xTra)(void*,int,sqlite3_file*);
1587     xTra = (int(*)(void*,int,sqlite3_file*))p->xBusyHandler;
1588     rc = xTra(p->pBusyArg, p->nBusy, pFile);
1589   }else{
1590     /* Legacy style busy handler callback */
1591     rc = p->xBusyHandler(p->pBusyArg, p->nBusy);
1592   }
1593   if( rc==0 ){
1594     p->nBusy = -1;
1595   }else{
1596     p->nBusy++;
1597   }
1598   return rc;
1599 }
1600 
1601 /*
1602 ** This routine sets the busy callback for an Sqlite database to the
1603 ** given callback function with the given argument.
1604 */
1605 int sqlite3_busy_handler(
1606   sqlite3 *db,
1607   int (*xBusy)(void*,int),
1608   void *pArg
1609 ){
1610 #ifdef SQLITE_ENABLE_API_ARMOR
1611   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1612 #endif
1613   sqlite3_mutex_enter(db->mutex);
1614   db->busyHandler.xBusyHandler = xBusy;
1615   db->busyHandler.pBusyArg = pArg;
1616   db->busyHandler.nBusy = 0;
1617   db->busyHandler.bExtraFileArg = 0;
1618   db->busyTimeout = 0;
1619   sqlite3_mutex_leave(db->mutex);
1620   return SQLITE_OK;
1621 }
1622 
1623 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1624 /*
1625 ** This routine sets the progress callback for an Sqlite database to the
1626 ** given callback function with the given argument. The progress callback will
1627 ** be invoked every nOps opcodes.
1628 */
1629 void sqlite3_progress_handler(
1630   sqlite3 *db,
1631   int nOps,
1632   int (*xProgress)(void*),
1633   void *pArg
1634 ){
1635 #ifdef SQLITE_ENABLE_API_ARMOR
1636   if( !sqlite3SafetyCheckOk(db) ){
1637     (void)SQLITE_MISUSE_BKPT;
1638     return;
1639   }
1640 #endif
1641   sqlite3_mutex_enter(db->mutex);
1642   if( nOps>0 ){
1643     db->xProgress = xProgress;
1644     db->nProgressOps = (unsigned)nOps;
1645     db->pProgressArg = pArg;
1646   }else{
1647     db->xProgress = 0;
1648     db->nProgressOps = 0;
1649     db->pProgressArg = 0;
1650   }
1651   sqlite3_mutex_leave(db->mutex);
1652 }
1653 #endif
1654 
1655 
1656 /*
1657 ** This routine installs a default busy handler that waits for the
1658 ** specified number of milliseconds before returning 0.
1659 */
1660 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1661 #ifdef SQLITE_ENABLE_API_ARMOR
1662   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1663 #endif
1664   if( ms>0 ){
1665     sqlite3_busy_handler(db, (int(*)(void*,int))sqliteDefaultBusyCallback,
1666                              (void*)db);
1667     db->busyTimeout = ms;
1668     db->busyHandler.bExtraFileArg = 1;
1669   }else{
1670     sqlite3_busy_handler(db, 0, 0);
1671   }
1672   return SQLITE_OK;
1673 }
1674 
1675 /*
1676 ** Cause any pending operation to stop at its earliest opportunity.
1677 */
1678 void sqlite3_interrupt(sqlite3 *db){
1679 #ifdef SQLITE_ENABLE_API_ARMOR
1680   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1681     (void)SQLITE_MISUSE_BKPT;
1682     return;
1683   }
1684 #endif
1685   db->u1.isInterrupted = 1;
1686 }
1687 
1688 
1689 /*
1690 ** This function is exactly the same as sqlite3_create_function(), except
1691 ** that it is designed to be called by internal code. The difference is
1692 ** that if a malloc() fails in sqlite3_create_function(), an error code
1693 ** is returned and the mallocFailed flag cleared.
1694 */
1695 int sqlite3CreateFunc(
1696   sqlite3 *db,
1697   const char *zFunctionName,
1698   int nArg,
1699   int enc,
1700   void *pUserData,
1701   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1702   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1703   void (*xFinal)(sqlite3_context*),
1704   void (*xValue)(sqlite3_context*),
1705   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1706   FuncDestructor *pDestructor
1707 ){
1708   FuncDef *p;
1709   int nName;
1710   int extraFlags;
1711 
1712   assert( sqlite3_mutex_held(db->mutex) );
1713   assert( xValue==0 || xSFunc==0 );
1714   if( zFunctionName==0                /* Must have a valid name */
1715    || (xSFunc!=0 && xFinal!=0)        /* Not both xSFunc and xFinal */
1716    || ((xFinal==0)!=(xStep==0))       /* Both or neither of xFinal and xStep */
1717    || ((xValue==0)!=(xInverse==0))    /* Both or neither of xValue, xInverse */
1718    || (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG)
1719    || (255<(nName = sqlite3Strlen30( zFunctionName)))
1720   ){
1721     return SQLITE_MISUSE_BKPT;
1722   }
1723 
1724   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1725   extraFlags = enc &  SQLITE_DETERMINISTIC;
1726   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1727 
1728 #ifndef SQLITE_OMIT_UTF16
1729   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1730   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1731   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1732   **
1733   ** If SQLITE_ANY is specified, add three versions of the function
1734   ** to the hash table.
1735   */
1736   if( enc==SQLITE_UTF16 ){
1737     enc = SQLITE_UTF16NATIVE;
1738   }else if( enc==SQLITE_ANY ){
1739     int rc;
1740     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1741          pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1742     if( rc==SQLITE_OK ){
1743       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1744           pUserData, xSFunc, xStep, xFinal, xValue, xInverse, pDestructor);
1745     }
1746     if( rc!=SQLITE_OK ){
1747       return rc;
1748     }
1749     enc = SQLITE_UTF16BE;
1750   }
1751 #else
1752   enc = SQLITE_UTF8;
1753 #endif
1754 
1755   /* Check if an existing function is being overridden or deleted. If so,
1756   ** and there are active VMs, then return SQLITE_BUSY. If a function
1757   ** is being overridden/deleted but there are no active VMs, allow the
1758   ** operation to continue but invalidate all precompiled statements.
1759   */
1760   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1761   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==(u32)enc && p->nArg==nArg ){
1762     if( db->nVdbeActive ){
1763       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1764         "unable to delete/modify user-function due to active statements");
1765       assert( !db->mallocFailed );
1766       return SQLITE_BUSY;
1767     }else{
1768       sqlite3ExpirePreparedStatements(db, 0);
1769     }
1770   }
1771 
1772   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1773   assert(p || db->mallocFailed);
1774   if( !p ){
1775     return SQLITE_NOMEM_BKPT;
1776   }
1777 
1778   /* If an older version of the function with a configured destructor is
1779   ** being replaced invoke the destructor function here. */
1780   functionDestroy(db, p);
1781 
1782   if( pDestructor ){
1783     pDestructor->nRef++;
1784   }
1785   p->u.pDestructor = pDestructor;
1786   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1787   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1788   p->xSFunc = xSFunc ? xSFunc : xStep;
1789   p->xFinalize = xFinal;
1790   p->xValue = xValue;
1791   p->xInverse = xInverse;
1792   p->pUserData = pUserData;
1793   p->nArg = (u16)nArg;
1794   return SQLITE_OK;
1795 }
1796 
1797 /*
1798 ** Worker function used by utf-8 APIs that create new functions:
1799 **
1800 **    sqlite3_create_function()
1801 **    sqlite3_create_function_v2()
1802 **    sqlite3_create_window_function()
1803 */
1804 static int createFunctionApi(
1805   sqlite3 *db,
1806   const char *zFunc,
1807   int nArg,
1808   int enc,
1809   void *p,
1810   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1811   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1812   void (*xFinal)(sqlite3_context*),
1813   void (*xValue)(sqlite3_context*),
1814   void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
1815   void(*xDestroy)(void*)
1816 ){
1817   int rc = SQLITE_ERROR;
1818   FuncDestructor *pArg = 0;
1819 
1820 #ifdef SQLITE_ENABLE_API_ARMOR
1821   if( !sqlite3SafetyCheckOk(db) ){
1822     return SQLITE_MISUSE_BKPT;
1823   }
1824 #endif
1825   sqlite3_mutex_enter(db->mutex);
1826   if( xDestroy ){
1827     pArg = (FuncDestructor *)sqlite3Malloc(sizeof(FuncDestructor));
1828     if( !pArg ){
1829       sqlite3OomFault(db);
1830       xDestroy(p);
1831       goto out;
1832     }
1833     pArg->nRef = 0;
1834     pArg->xDestroy = xDestroy;
1835     pArg->pUserData = p;
1836   }
1837   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p,
1838       xSFunc, xStep, xFinal, xValue, xInverse, pArg
1839   );
1840   if( pArg && pArg->nRef==0 ){
1841     assert( rc!=SQLITE_OK );
1842     xDestroy(p);
1843     sqlite3_free(pArg);
1844   }
1845 
1846  out:
1847   rc = sqlite3ApiExit(db, rc);
1848   sqlite3_mutex_leave(db->mutex);
1849   return rc;
1850 }
1851 
1852 /*
1853 ** Create new user functions.
1854 */
1855 int sqlite3_create_function(
1856   sqlite3 *db,
1857   const char *zFunc,
1858   int nArg,
1859   int enc,
1860   void *p,
1861   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1862   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1863   void (*xFinal)(sqlite3_context*)
1864 ){
1865   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1866                                     xFinal, 0, 0, 0);
1867 }
1868 int sqlite3_create_function_v2(
1869   sqlite3 *db,
1870   const char *zFunc,
1871   int nArg,
1872   int enc,
1873   void *p,
1874   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1875   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1876   void (*xFinal)(sqlite3_context*),
1877   void (*xDestroy)(void *)
1878 ){
1879   return createFunctionApi(db, zFunc, nArg, enc, p, xSFunc, xStep,
1880                                     xFinal, 0, 0, xDestroy);
1881 }
1882 int sqlite3_create_window_function(
1883   sqlite3 *db,
1884   const char *zFunc,
1885   int nArg,
1886   int enc,
1887   void *p,
1888   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1889   void (*xFinal)(sqlite3_context*),
1890   void (*xValue)(sqlite3_context*),
1891   void (*xInverse)(sqlite3_context*,int,sqlite3_value **),
1892   void (*xDestroy)(void *)
1893 ){
1894   return createFunctionApi(db, zFunc, nArg, enc, p, 0, xStep,
1895                                     xFinal, xValue, xInverse, xDestroy);
1896 }
1897 
1898 #ifndef SQLITE_OMIT_UTF16
1899 int sqlite3_create_function16(
1900   sqlite3 *db,
1901   const void *zFunctionName,
1902   int nArg,
1903   int eTextRep,
1904   void *p,
1905   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1906   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1907   void (*xFinal)(sqlite3_context*)
1908 ){
1909   int rc;
1910   char *zFunc8;
1911 
1912 #ifdef SQLITE_ENABLE_API_ARMOR
1913   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1914 #endif
1915   sqlite3_mutex_enter(db->mutex);
1916   assert( !db->mallocFailed );
1917   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1918   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0,0,0);
1919   sqlite3DbFree(db, zFunc8);
1920   rc = sqlite3ApiExit(db, rc);
1921   sqlite3_mutex_leave(db->mutex);
1922   return rc;
1923 }
1924 #endif
1925 
1926 
1927 /*
1928 ** The following is the implementation of an SQL function that always
1929 ** fails with an error message stating that the function is used in the
1930 ** wrong context.  The sqlite3_overload_function() API might construct
1931 ** SQL function that use this routine so that the functions will exist
1932 ** for name resolution but are actually overloaded by the xFindFunction
1933 ** method of virtual tables.
1934 */
1935 static void sqlite3InvalidFunction(
1936   sqlite3_context *context,  /* The function calling context */
1937   int NotUsed,               /* Number of arguments to the function */
1938   sqlite3_value **NotUsed2   /* Value of each argument */
1939 ){
1940   const char *zName = (const char*)sqlite3_user_data(context);
1941   char *zErr;
1942   UNUSED_PARAMETER2(NotUsed, NotUsed2);
1943   zErr = sqlite3_mprintf(
1944       "unable to use function %s in the requested context", zName);
1945   sqlite3_result_error(context, zErr, -1);
1946   sqlite3_free(zErr);
1947 }
1948 
1949 /*
1950 ** Declare that a function has been overloaded by a virtual table.
1951 **
1952 ** If the function already exists as a regular global function, then
1953 ** this routine is a no-op.  If the function does not exist, then create
1954 ** a new one that always throws a run-time error.
1955 **
1956 ** When virtual tables intend to provide an overloaded function, they
1957 ** should call this routine to make sure the global function exists.
1958 ** A global function must exist in order for name resolution to work
1959 ** properly.
1960 */
1961 int sqlite3_overload_function(
1962   sqlite3 *db,
1963   const char *zName,
1964   int nArg
1965 ){
1966   int rc;
1967   char *zCopy;
1968 
1969 #ifdef SQLITE_ENABLE_API_ARMOR
1970   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1971     return SQLITE_MISUSE_BKPT;
1972   }
1973 #endif
1974   sqlite3_mutex_enter(db->mutex);
1975   rc = sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)!=0;
1976   sqlite3_mutex_leave(db->mutex);
1977   if( rc ) return SQLITE_OK;
1978   zCopy = sqlite3_mprintf(zName);
1979   if( zCopy==0 ) return SQLITE_NOMEM;
1980   return sqlite3_create_function_v2(db, zName, nArg, SQLITE_UTF8,
1981                            zCopy, sqlite3InvalidFunction, 0, 0, sqlite3_free);
1982 }
1983 
1984 #ifndef SQLITE_OMIT_TRACE
1985 /*
1986 ** Register a trace function.  The pArg from the previously registered trace
1987 ** is returned.
1988 **
1989 ** A NULL trace function means that no tracing is executes.  A non-NULL
1990 ** trace is a pointer to a function that is invoked at the start of each
1991 ** SQL statement.
1992 */
1993 #ifndef SQLITE_OMIT_DEPRECATED
1994 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1995   void *pOld;
1996 
1997 #ifdef SQLITE_ENABLE_API_ARMOR
1998   if( !sqlite3SafetyCheckOk(db) ){
1999     (void)SQLITE_MISUSE_BKPT;
2000     return 0;
2001   }
2002 #endif
2003   sqlite3_mutex_enter(db->mutex);
2004   pOld = db->pTraceArg;
2005   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
2006   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
2007   db->pTraceArg = pArg;
2008   sqlite3_mutex_leave(db->mutex);
2009   return pOld;
2010 }
2011 #endif /* SQLITE_OMIT_DEPRECATED */
2012 
2013 /* Register a trace callback using the version-2 interface.
2014 */
2015 int sqlite3_trace_v2(
2016   sqlite3 *db,                               /* Trace this connection */
2017   unsigned mTrace,                           /* Mask of events to be traced */
2018   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
2019   void *pArg                                 /* Context */
2020 ){
2021 #ifdef SQLITE_ENABLE_API_ARMOR
2022   if( !sqlite3SafetyCheckOk(db) ){
2023     return SQLITE_MISUSE_BKPT;
2024   }
2025 #endif
2026   sqlite3_mutex_enter(db->mutex);
2027   if( mTrace==0 ) xTrace = 0;
2028   if( xTrace==0 ) mTrace = 0;
2029   db->mTrace = mTrace;
2030   db->xTrace = xTrace;
2031   db->pTraceArg = pArg;
2032   sqlite3_mutex_leave(db->mutex);
2033   return SQLITE_OK;
2034 }
2035 
2036 #ifndef SQLITE_OMIT_DEPRECATED
2037 /*
2038 ** Register a profile function.  The pArg from the previously registered
2039 ** profile function is returned.
2040 **
2041 ** A NULL profile function means that no profiling is executes.  A non-NULL
2042 ** profile is a pointer to a function that is invoked at the conclusion of
2043 ** each SQL statement that is run.
2044 */
2045 void *sqlite3_profile(
2046   sqlite3 *db,
2047   void (*xProfile)(void*,const char*,sqlite_uint64),
2048   void *pArg
2049 ){
2050   void *pOld;
2051 
2052 #ifdef SQLITE_ENABLE_API_ARMOR
2053   if( !sqlite3SafetyCheckOk(db) ){
2054     (void)SQLITE_MISUSE_BKPT;
2055     return 0;
2056   }
2057 #endif
2058   sqlite3_mutex_enter(db->mutex);
2059   pOld = db->pProfileArg;
2060   db->xProfile = xProfile;
2061   db->pProfileArg = pArg;
2062   db->mTrace &= SQLITE_TRACE_NONLEGACY_MASK;
2063   if( db->xProfile ) db->mTrace |= SQLITE_TRACE_XPROFILE;
2064   sqlite3_mutex_leave(db->mutex);
2065   return pOld;
2066 }
2067 #endif /* SQLITE_OMIT_DEPRECATED */
2068 #endif /* SQLITE_OMIT_TRACE */
2069 
2070 /*
2071 ** Register a function to be invoked when a transaction commits.
2072 ** If the invoked function returns non-zero, then the commit becomes a
2073 ** rollback.
2074 */
2075 void *sqlite3_commit_hook(
2076   sqlite3 *db,              /* Attach the hook to this database */
2077   int (*xCallback)(void*),  /* Function to invoke on each commit */
2078   void *pArg                /* Argument to the function */
2079 ){
2080   void *pOld;
2081 
2082 #ifdef SQLITE_ENABLE_API_ARMOR
2083   if( !sqlite3SafetyCheckOk(db) ){
2084     (void)SQLITE_MISUSE_BKPT;
2085     return 0;
2086   }
2087 #endif
2088   sqlite3_mutex_enter(db->mutex);
2089   pOld = db->pCommitArg;
2090   db->xCommitCallback = xCallback;
2091   db->pCommitArg = pArg;
2092   sqlite3_mutex_leave(db->mutex);
2093   return pOld;
2094 }
2095 
2096 /*
2097 ** Register a callback to be invoked each time a row is updated,
2098 ** inserted or deleted using this database connection.
2099 */
2100 void *sqlite3_update_hook(
2101   sqlite3 *db,              /* Attach the hook to this database */
2102   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
2103   void *pArg                /* Argument to the function */
2104 ){
2105   void *pRet;
2106 
2107 #ifdef SQLITE_ENABLE_API_ARMOR
2108   if( !sqlite3SafetyCheckOk(db) ){
2109     (void)SQLITE_MISUSE_BKPT;
2110     return 0;
2111   }
2112 #endif
2113   sqlite3_mutex_enter(db->mutex);
2114   pRet = db->pUpdateArg;
2115   db->xUpdateCallback = xCallback;
2116   db->pUpdateArg = pArg;
2117   sqlite3_mutex_leave(db->mutex);
2118   return pRet;
2119 }
2120 
2121 /*
2122 ** Register a callback to be invoked each time a transaction is rolled
2123 ** back by this database connection.
2124 */
2125 void *sqlite3_rollback_hook(
2126   sqlite3 *db,              /* Attach the hook to this database */
2127   void (*xCallback)(void*), /* Callback function */
2128   void *pArg                /* Argument to the function */
2129 ){
2130   void *pRet;
2131 
2132 #ifdef SQLITE_ENABLE_API_ARMOR
2133   if( !sqlite3SafetyCheckOk(db) ){
2134     (void)SQLITE_MISUSE_BKPT;
2135     return 0;
2136   }
2137 #endif
2138   sqlite3_mutex_enter(db->mutex);
2139   pRet = db->pRollbackArg;
2140   db->xRollbackCallback = xCallback;
2141   db->pRollbackArg = pArg;
2142   sqlite3_mutex_leave(db->mutex);
2143   return pRet;
2144 }
2145 
2146 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
2147 /*
2148 ** Register a callback to be invoked each time a row is updated,
2149 ** inserted or deleted using this database connection.
2150 */
2151 void *sqlite3_preupdate_hook(
2152   sqlite3 *db,              /* Attach the hook to this database */
2153   void(*xCallback)(         /* Callback function */
2154     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
2155   void *pArg                /* First callback argument */
2156 ){
2157   void *pRet;
2158   sqlite3_mutex_enter(db->mutex);
2159   pRet = db->pPreUpdateArg;
2160   db->xPreUpdateCallback = xCallback;
2161   db->pPreUpdateArg = pArg;
2162   sqlite3_mutex_leave(db->mutex);
2163   return pRet;
2164 }
2165 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2166 
2167 #ifndef SQLITE_OMIT_WAL
2168 /*
2169 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2170 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2171 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2172 ** wal_autocheckpoint()).
2173 */
2174 int sqlite3WalDefaultHook(
2175   void *pClientData,     /* Argument */
2176   sqlite3 *db,           /* Connection */
2177   const char *zDb,       /* Database */
2178   int nFrame             /* Size of WAL */
2179 ){
2180   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2181     sqlite3BeginBenignMalloc();
2182     sqlite3_wal_checkpoint(db, zDb);
2183     sqlite3EndBenignMalloc();
2184   }
2185   return SQLITE_OK;
2186 }
2187 #endif /* SQLITE_OMIT_WAL */
2188 
2189 /*
2190 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2191 ** a database after committing a transaction if there are nFrame or
2192 ** more frames in the log file. Passing zero or a negative value as the
2193 ** nFrame parameter disables automatic checkpoints entirely.
2194 **
2195 ** The callback registered by this function replaces any existing callback
2196 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2197 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2198 ** configured by this function.
2199 */
2200 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2201 #ifdef SQLITE_OMIT_WAL
2202   UNUSED_PARAMETER(db);
2203   UNUSED_PARAMETER(nFrame);
2204 #else
2205 #ifdef SQLITE_ENABLE_API_ARMOR
2206   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2207 #endif
2208   if( nFrame>0 ){
2209     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2210   }else{
2211     sqlite3_wal_hook(db, 0, 0);
2212   }
2213 #endif
2214   return SQLITE_OK;
2215 }
2216 
2217 /*
2218 ** Register a callback to be invoked each time a transaction is written
2219 ** into the write-ahead-log by this database connection.
2220 */
2221 void *sqlite3_wal_hook(
2222   sqlite3 *db,                    /* Attach the hook to this db handle */
2223   int(*xCallback)(void *, sqlite3*, const char*, int),
2224   void *pArg                      /* First argument passed to xCallback() */
2225 ){
2226 #ifndef SQLITE_OMIT_WAL
2227   void *pRet;
2228 #ifdef SQLITE_ENABLE_API_ARMOR
2229   if( !sqlite3SafetyCheckOk(db) ){
2230     (void)SQLITE_MISUSE_BKPT;
2231     return 0;
2232   }
2233 #endif
2234   sqlite3_mutex_enter(db->mutex);
2235   pRet = db->pWalArg;
2236   db->xWalCallback = xCallback;
2237   db->pWalArg = pArg;
2238   sqlite3_mutex_leave(db->mutex);
2239   return pRet;
2240 #else
2241   return 0;
2242 #endif
2243 }
2244 
2245 /*
2246 ** Checkpoint database zDb.
2247 */
2248 int sqlite3_wal_checkpoint_v2(
2249   sqlite3 *db,                    /* Database handle */
2250   const char *zDb,                /* Name of attached database (or NULL) */
2251   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2252   int *pnLog,                     /* OUT: Size of WAL log in frames */
2253   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2254 ){
2255 #ifdef SQLITE_OMIT_WAL
2256   return SQLITE_OK;
2257 #else
2258   int rc;                         /* Return code */
2259   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2260 
2261 #ifdef SQLITE_ENABLE_API_ARMOR
2262   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2263 #endif
2264 
2265   /* Initialize the output variables to -1 in case an error occurs. */
2266   if( pnLog ) *pnLog = -1;
2267   if( pnCkpt ) *pnCkpt = -1;
2268 
2269   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2270   assert( SQLITE_CHECKPOINT_FULL==1 );
2271   assert( SQLITE_CHECKPOINT_RESTART==2 );
2272   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2273   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2274     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2275     ** mode: */
2276     return SQLITE_MISUSE;
2277   }
2278 
2279   sqlite3_mutex_enter(db->mutex);
2280   if( zDb && zDb[0] ){
2281     iDb = sqlite3FindDbName(db, zDb);
2282   }
2283   if( iDb<0 ){
2284     rc = SQLITE_ERROR;
2285     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2286   }else{
2287     db->busyHandler.nBusy = 0;
2288     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2289     sqlite3Error(db, rc);
2290   }
2291   rc = sqlite3ApiExit(db, rc);
2292 
2293   /* If there are no active statements, clear the interrupt flag at this
2294   ** point.  */
2295   if( db->nVdbeActive==0 ){
2296     db->u1.isInterrupted = 0;
2297   }
2298 
2299   sqlite3_mutex_leave(db->mutex);
2300   return rc;
2301 #endif
2302 }
2303 
2304 
2305 /*
2306 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2307 ** to contains a zero-length string, all attached databases are
2308 ** checkpointed.
2309 */
2310 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2311   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2312   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2313   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2314 }
2315 
2316 #ifndef SQLITE_OMIT_WAL
2317 /*
2318 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2319 ** not currently open in WAL mode.
2320 **
2321 ** If a transaction is open on the database being checkpointed, this
2322 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2323 ** an error occurs while running the checkpoint, an SQLite error code is
2324 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2325 **
2326 ** The mutex on database handle db should be held by the caller. The mutex
2327 ** associated with the specific b-tree being checkpointed is taken by
2328 ** this function while the checkpoint is running.
2329 **
2330 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2331 ** checkpointed. If an error is encountered it is returned immediately -
2332 ** no attempt is made to checkpoint any remaining databases.
2333 **
2334 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL, RESTART
2335 ** or TRUNCATE.
2336 */
2337 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2338   int rc = SQLITE_OK;             /* Return code */
2339   int i;                          /* Used to iterate through attached dbs */
2340   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2341 
2342   assert( sqlite3_mutex_held(db->mutex) );
2343   assert( !pnLog || *pnLog==-1 );
2344   assert( !pnCkpt || *pnCkpt==-1 );
2345 
2346   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2347     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2348       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2349       pnLog = 0;
2350       pnCkpt = 0;
2351       if( rc==SQLITE_BUSY ){
2352         bBusy = 1;
2353         rc = SQLITE_OK;
2354       }
2355     }
2356   }
2357 
2358   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2359 }
2360 #endif /* SQLITE_OMIT_WAL */
2361 
2362 /*
2363 ** This function returns true if main-memory should be used instead of
2364 ** a temporary file for transient pager files and statement journals.
2365 ** The value returned depends on the value of db->temp_store (runtime
2366 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2367 ** following table describes the relationship between these two values
2368 ** and this functions return value.
2369 **
2370 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2371 **   -----------------     --------------     ------------------------------
2372 **   0                     any                file      (return 0)
2373 **   1                     1                  file      (return 0)
2374 **   1                     2                  memory    (return 1)
2375 **   1                     0                  file      (return 0)
2376 **   2                     1                  file      (return 0)
2377 **   2                     2                  memory    (return 1)
2378 **   2                     0                  memory    (return 1)
2379 **   3                     any                memory    (return 1)
2380 */
2381 int sqlite3TempInMemory(const sqlite3 *db){
2382 #if SQLITE_TEMP_STORE==1
2383   return ( db->temp_store==2 );
2384 #endif
2385 #if SQLITE_TEMP_STORE==2
2386   return ( db->temp_store!=1 );
2387 #endif
2388 #if SQLITE_TEMP_STORE==3
2389   UNUSED_PARAMETER(db);
2390   return 1;
2391 #endif
2392 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2393   UNUSED_PARAMETER(db);
2394   return 0;
2395 #endif
2396 }
2397 
2398 /*
2399 ** Return UTF-8 encoded English language explanation of the most recent
2400 ** error.
2401 */
2402 const char *sqlite3_errmsg(sqlite3 *db){
2403   const char *z;
2404   if( !db ){
2405     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2406   }
2407   if( !sqlite3SafetyCheckSickOrOk(db) ){
2408     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2409   }
2410   sqlite3_mutex_enter(db->mutex);
2411   if( db->mallocFailed ){
2412     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2413   }else{
2414     testcase( db->pErr==0 );
2415     z = db->errCode ? (char*)sqlite3_value_text(db->pErr) : 0;
2416     assert( !db->mallocFailed );
2417     if( z==0 ){
2418       z = sqlite3ErrStr(db->errCode);
2419     }
2420   }
2421   sqlite3_mutex_leave(db->mutex);
2422   return z;
2423 }
2424 
2425 #ifndef SQLITE_OMIT_UTF16
2426 /*
2427 ** Return UTF-16 encoded English language explanation of the most recent
2428 ** error.
2429 */
2430 const void *sqlite3_errmsg16(sqlite3 *db){
2431   static const u16 outOfMem[] = {
2432     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2433   };
2434   static const u16 misuse[] = {
2435     'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
2436     'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
2437     'm', 'i', 's', 'u', 's', 'e', 0
2438   };
2439 
2440   const void *z;
2441   if( !db ){
2442     return (void *)outOfMem;
2443   }
2444   if( !sqlite3SafetyCheckSickOrOk(db) ){
2445     return (void *)misuse;
2446   }
2447   sqlite3_mutex_enter(db->mutex);
2448   if( db->mallocFailed ){
2449     z = (void *)outOfMem;
2450   }else{
2451     z = sqlite3_value_text16(db->pErr);
2452     if( z==0 ){
2453       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2454       z = sqlite3_value_text16(db->pErr);
2455     }
2456     /* A malloc() may have failed within the call to sqlite3_value_text16()
2457     ** above. If this is the case, then the db->mallocFailed flag needs to
2458     ** be cleared before returning. Do this directly, instead of via
2459     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2460     */
2461     sqlite3OomClear(db);
2462   }
2463   sqlite3_mutex_leave(db->mutex);
2464   return z;
2465 }
2466 #endif /* SQLITE_OMIT_UTF16 */
2467 
2468 /*
2469 ** Return the most recent error code generated by an SQLite routine. If NULL is
2470 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2471 */
2472 int sqlite3_errcode(sqlite3 *db){
2473   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2474     return SQLITE_MISUSE_BKPT;
2475   }
2476   if( !db || db->mallocFailed ){
2477     return SQLITE_NOMEM_BKPT;
2478   }
2479   return db->errCode & db->errMask;
2480 }
2481 int sqlite3_extended_errcode(sqlite3 *db){
2482   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2483     return SQLITE_MISUSE_BKPT;
2484   }
2485   if( !db || db->mallocFailed ){
2486     return SQLITE_NOMEM_BKPT;
2487   }
2488   return db->errCode;
2489 }
2490 int sqlite3_system_errno(sqlite3 *db){
2491   return db ? db->iSysErrno : 0;
2492 }
2493 
2494 /*
2495 ** Return a string that describes the kind of error specified in the
2496 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2497 ** function.
2498 */
2499 const char *sqlite3_errstr(int rc){
2500   return sqlite3ErrStr(rc);
2501 }
2502 
2503 /*
2504 ** Create a new collating function for database "db".  The name is zName
2505 ** and the encoding is enc.
2506 */
2507 static int createCollation(
2508   sqlite3* db,
2509   const char *zName,
2510   u8 enc,
2511   void* pCtx,
2512   int(*xCompare)(void*,int,const void*,int,const void*),
2513   void(*xDel)(void*)
2514 ){
2515   CollSeq *pColl;
2516   int enc2;
2517 
2518   assert( sqlite3_mutex_held(db->mutex) );
2519 
2520   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2521   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2522   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2523   */
2524   enc2 = enc;
2525   testcase( enc2==SQLITE_UTF16 );
2526   testcase( enc2==SQLITE_UTF16_ALIGNED );
2527   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2528     enc2 = SQLITE_UTF16NATIVE;
2529   }
2530   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2531     return SQLITE_MISUSE_BKPT;
2532   }
2533 
2534   /* Check if this call is removing or replacing an existing collation
2535   ** sequence. If so, and there are active VMs, return busy. If there
2536   ** are no active VMs, invalidate any pre-compiled statements.
2537   */
2538   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2539   if( pColl && pColl->xCmp ){
2540     if( db->nVdbeActive ){
2541       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2542         "unable to delete/modify collation sequence due to active statements");
2543       return SQLITE_BUSY;
2544     }
2545     sqlite3ExpirePreparedStatements(db, 0);
2546 
2547     /* If collation sequence pColl was created directly by a call to
2548     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2549     ** then any copies made by synthCollSeq() need to be invalidated.
2550     ** Also, collation destructor - CollSeq.xDel() - function may need
2551     ** to be called.
2552     */
2553     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2554       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2555       int j;
2556       for(j=0; j<3; j++){
2557         CollSeq *p = &aColl[j];
2558         if( p->enc==pColl->enc ){
2559           if( p->xDel ){
2560             p->xDel(p->pUser);
2561           }
2562           p->xCmp = 0;
2563         }
2564       }
2565     }
2566   }
2567 
2568   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2569   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2570   pColl->xCmp = xCompare;
2571   pColl->pUser = pCtx;
2572   pColl->xDel = xDel;
2573   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2574   sqlite3Error(db, SQLITE_OK);
2575   return SQLITE_OK;
2576 }
2577 
2578 
2579 /*
2580 ** This array defines hard upper bounds on limit values.  The
2581 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2582 ** #defines in sqlite3.h.
2583 */
2584 static const int aHardLimit[] = {
2585   SQLITE_MAX_LENGTH,
2586   SQLITE_MAX_SQL_LENGTH,
2587   SQLITE_MAX_COLUMN,
2588   SQLITE_MAX_EXPR_DEPTH,
2589   SQLITE_MAX_COMPOUND_SELECT,
2590   SQLITE_MAX_VDBE_OP,
2591   SQLITE_MAX_FUNCTION_ARG,
2592   SQLITE_MAX_ATTACHED,
2593   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2594   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2595   SQLITE_MAX_TRIGGER_DEPTH,
2596   SQLITE_MAX_WORKER_THREADS,
2597 };
2598 
2599 /*
2600 ** Make sure the hard limits are set to reasonable values
2601 */
2602 #if SQLITE_MAX_LENGTH<100
2603 # error SQLITE_MAX_LENGTH must be at least 100
2604 #endif
2605 #if SQLITE_MAX_SQL_LENGTH<100
2606 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2607 #endif
2608 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2609 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2610 #endif
2611 #if SQLITE_MAX_COMPOUND_SELECT<2
2612 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2613 #endif
2614 #if SQLITE_MAX_VDBE_OP<40
2615 # error SQLITE_MAX_VDBE_OP must be at least 40
2616 #endif
2617 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2618 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2619 #endif
2620 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2621 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2622 #endif
2623 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2624 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2625 #endif
2626 #if SQLITE_MAX_COLUMN>32767
2627 # error SQLITE_MAX_COLUMN must not exceed 32767
2628 #endif
2629 #if SQLITE_MAX_TRIGGER_DEPTH<1
2630 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2631 #endif
2632 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2633 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2634 #endif
2635 
2636 
2637 /*
2638 ** Change the value of a limit.  Report the old value.
2639 ** If an invalid limit index is supplied, report -1.
2640 ** Make no changes but still report the old value if the
2641 ** new limit is negative.
2642 **
2643 ** A new lower limit does not shrink existing constructs.
2644 ** It merely prevents new constructs that exceed the limit
2645 ** from forming.
2646 */
2647 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2648   int oldLimit;
2649 
2650 #ifdef SQLITE_ENABLE_API_ARMOR
2651   if( !sqlite3SafetyCheckOk(db) ){
2652     (void)SQLITE_MISUSE_BKPT;
2653     return -1;
2654   }
2655 #endif
2656 
2657   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2658   ** there is a hard upper bound set at compile-time by a C preprocessor
2659   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2660   ** "_MAX_".)
2661   */
2662   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2663   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2664   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2665   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2666   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2667   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2668   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2669   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2670   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2671                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2672   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2673   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2674   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2675   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2676 
2677 
2678   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2679     return -1;
2680   }
2681   oldLimit = db->aLimit[limitId];
2682   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2683     if( newLimit>aHardLimit[limitId] ){
2684       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2685     }
2686     db->aLimit[limitId] = newLimit;
2687   }
2688   return oldLimit;                     /* IMP: R-53341-35419 */
2689 }
2690 
2691 /*
2692 ** This function is used to parse both URIs and non-URI filenames passed by the
2693 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2694 ** URIs specified as part of ATTACH statements.
2695 **
2696 ** The first argument to this function is the name of the VFS to use (or
2697 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2698 ** query parameter. The second argument contains the URI (or non-URI filename)
2699 ** itself. When this function is called the *pFlags variable should contain
2700 ** the default flags to open the database handle with. The value stored in
2701 ** *pFlags may be updated before returning if the URI filename contains
2702 ** "cache=xxx" or "mode=xxx" query parameters.
2703 **
2704 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2705 ** the VFS that should be used to open the database file. *pzFile is set to
2706 ** point to a buffer containing the name of the file to open. It is the
2707 ** responsibility of the caller to eventually call sqlite3_free() to release
2708 ** this buffer.
2709 **
2710 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2711 ** may be set to point to a buffer containing an English language error
2712 ** message. It is the responsibility of the caller to eventually release
2713 ** this buffer by calling sqlite3_free().
2714 */
2715 int sqlite3ParseUri(
2716   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2717   const char *zUri,               /* Nul-terminated URI to parse */
2718   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2719   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2720   char **pzFile,                  /* OUT: Filename component of URI */
2721   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2722 ){
2723   int rc = SQLITE_OK;
2724   unsigned int flags = *pFlags;
2725   const char *zVfs = zDefaultVfs;
2726   char *zFile;
2727   char c;
2728   int nUri = sqlite3Strlen30(zUri);
2729 
2730   assert( *pzErrMsg==0 );
2731 
2732   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2733             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2734    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2735   ){
2736     char *zOpt;
2737     int eState;                   /* Parser state when parsing URI */
2738     int iIn;                      /* Input character index */
2739     int iOut = 0;                 /* Output character index */
2740     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2741 
2742     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2743     ** method that there may be extra parameters following the file-name.  */
2744     flags |= SQLITE_OPEN_URI;
2745 
2746     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2747     zFile = sqlite3_malloc64(nByte);
2748     if( !zFile ) return SQLITE_NOMEM_BKPT;
2749 
2750     iIn = 5;
2751 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2752     if( strncmp(zUri+5, "///", 3)==0 ){
2753       iIn = 7;
2754       /* The following condition causes URIs with five leading / characters
2755       ** like file://///host/path to be converted into UNCs like //host/path.
2756       ** The correct URI for that UNC has only two or four leading / characters
2757       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2758       ** common error, we are told, so we handle it as a special case. */
2759       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2760     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2761       iIn = 16;
2762     }
2763 #else
2764     /* Discard the scheme and authority segments of the URI. */
2765     if( zUri[5]=='/' && zUri[6]=='/' ){
2766       iIn = 7;
2767       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2768       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2769         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2770             iIn-7, &zUri[7]);
2771         rc = SQLITE_ERROR;
2772         goto parse_uri_out;
2773       }
2774     }
2775 #endif
2776 
2777     /* Copy the filename and any query parameters into the zFile buffer.
2778     ** Decode %HH escape codes along the way.
2779     **
2780     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2781     ** on the parsing context. As follows:
2782     **
2783     **   0: Parsing file-name.
2784     **   1: Parsing name section of a name=value query parameter.
2785     **   2: Parsing value section of a name=value query parameter.
2786     */
2787     eState = 0;
2788     while( (c = zUri[iIn])!=0 && c!='#' ){
2789       iIn++;
2790       if( c=='%'
2791        && sqlite3Isxdigit(zUri[iIn])
2792        && sqlite3Isxdigit(zUri[iIn+1])
2793       ){
2794         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2795         octet += sqlite3HexToInt(zUri[iIn++]);
2796 
2797         assert( octet>=0 && octet<256 );
2798         if( octet==0 ){
2799 #ifndef SQLITE_ENABLE_URI_00_ERROR
2800           /* This branch is taken when "%00" appears within the URI. In this
2801           ** case we ignore all text in the remainder of the path, name or
2802           ** value currently being parsed. So ignore the current character
2803           ** and skip to the next "?", "=" or "&", as appropriate. */
2804           while( (c = zUri[iIn])!=0 && c!='#'
2805               && (eState!=0 || c!='?')
2806               && (eState!=1 || (c!='=' && c!='&'))
2807               && (eState!=2 || c!='&')
2808           ){
2809             iIn++;
2810           }
2811           continue;
2812 #else
2813           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2814           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2815           rc = SQLITE_ERROR;
2816           goto parse_uri_out;
2817 #endif
2818         }
2819         c = octet;
2820       }else if( eState==1 && (c=='&' || c=='=') ){
2821         if( zFile[iOut-1]==0 ){
2822           /* An empty option name. Ignore this option altogether. */
2823           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2824           continue;
2825         }
2826         if( c=='&' ){
2827           zFile[iOut++] = '\0';
2828         }else{
2829           eState = 2;
2830         }
2831         c = 0;
2832       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2833         c = 0;
2834         eState = 1;
2835       }
2836       zFile[iOut++] = c;
2837     }
2838     if( eState==1 ) zFile[iOut++] = '\0';
2839     zFile[iOut++] = '\0';
2840     zFile[iOut++] = '\0';
2841 
2842     /* Check if there were any options specified that should be interpreted
2843     ** here. Options that are interpreted here include "vfs" and those that
2844     ** correspond to flags that may be passed to the sqlite3_open_v2()
2845     ** method. */
2846     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2847     while( zOpt[0] ){
2848       int nOpt = sqlite3Strlen30(zOpt);
2849       char *zVal = &zOpt[nOpt+1];
2850       int nVal = sqlite3Strlen30(zVal);
2851 
2852       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2853         zVfs = zVal;
2854       }else{
2855         struct OpenMode {
2856           const char *z;
2857           int mode;
2858         } *aMode = 0;
2859         char *zModeType = 0;
2860         int mask = 0;
2861         int limit = 0;
2862 
2863         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2864           static struct OpenMode aCacheMode[] = {
2865             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2866             { "private", SQLITE_OPEN_PRIVATECACHE },
2867             { 0, 0 }
2868           };
2869 
2870           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2871           aMode = aCacheMode;
2872           limit = mask;
2873           zModeType = "cache";
2874         }
2875         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2876           static struct OpenMode aOpenMode[] = {
2877             { "ro",  SQLITE_OPEN_READONLY },
2878             { "rw",  SQLITE_OPEN_READWRITE },
2879             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2880             { "memory", SQLITE_OPEN_MEMORY },
2881             { 0, 0 }
2882           };
2883 
2884           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2885                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2886           aMode = aOpenMode;
2887           limit = mask & flags;
2888           zModeType = "access";
2889         }
2890 
2891         if( aMode ){
2892           int i;
2893           int mode = 0;
2894           for(i=0; aMode[i].z; i++){
2895             const char *z = aMode[i].z;
2896             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2897               mode = aMode[i].mode;
2898               break;
2899             }
2900           }
2901           if( mode==0 ){
2902             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2903             rc = SQLITE_ERROR;
2904             goto parse_uri_out;
2905           }
2906           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2907             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2908                                         zModeType, zVal);
2909             rc = SQLITE_PERM;
2910             goto parse_uri_out;
2911           }
2912           flags = (flags & ~mask) | mode;
2913         }
2914       }
2915 
2916       zOpt = &zVal[nVal+1];
2917     }
2918 
2919   }else{
2920     zFile = sqlite3_malloc64(nUri+2);
2921     if( !zFile ) return SQLITE_NOMEM_BKPT;
2922     if( nUri ){
2923       memcpy(zFile, zUri, nUri);
2924     }
2925     zFile[nUri] = '\0';
2926     zFile[nUri+1] = '\0';
2927     flags &= ~SQLITE_OPEN_URI;
2928   }
2929 
2930   *ppVfs = sqlite3_vfs_find(zVfs);
2931   if( *ppVfs==0 ){
2932     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2933     rc = SQLITE_ERROR;
2934   }
2935  parse_uri_out:
2936   if( rc!=SQLITE_OK ){
2937     sqlite3_free(zFile);
2938     zFile = 0;
2939   }
2940   *pFlags = flags;
2941   *pzFile = zFile;
2942   return rc;
2943 }
2944 
2945 #if defined(SQLITE_HAS_CODEC)
2946 /*
2947 ** Process URI filename query parameters relevant to the SQLite Encryption
2948 ** Extension.  Return true if any of the relevant query parameters are
2949 ** seen and return false if not.
2950 */
2951 int sqlite3CodecQueryParameters(
2952   sqlite3 *db,           /* Database connection */
2953   const char *zDb,       /* Which schema is being created/attached */
2954   const char *zUri       /* URI filename */
2955 ){
2956   const char *zKey;
2957   if( (zKey = sqlite3_uri_parameter(zUri, "hexkey"))!=0 && zKey[0] ){
2958     u8 iByte;
2959     int i;
2960     char zDecoded[40];
2961     for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
2962       iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
2963       if( (i&1)!=0 ) zDecoded[i/2] = iByte;
2964     }
2965     sqlite3_key_v2(db, zDb, zDecoded, i/2);
2966     return 1;
2967   }else if( (zKey = sqlite3_uri_parameter(zUri, "key"))!=0 ){
2968     sqlite3_key_v2(db, zDb, zKey, sqlite3Strlen30(zKey));
2969     return 1;
2970   }else if( (zKey = sqlite3_uri_parameter(zUri, "textkey"))!=0 ){
2971     sqlite3_key_v2(db, zDb, zKey, -1);
2972     return 1;
2973   }else{
2974     return 0;
2975   }
2976 }
2977 #endif
2978 
2979 
2980 /*
2981 ** This routine does the work of opening a database on behalf of
2982 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2983 ** is UTF-8 encoded.
2984 */
2985 static int openDatabase(
2986   const char *zFilename, /* Database filename UTF-8 encoded */
2987   sqlite3 **ppDb,        /* OUT: Returned database handle */
2988   unsigned int flags,    /* Operational flags */
2989   const char *zVfs       /* Name of the VFS to use */
2990 ){
2991   sqlite3 *db;                    /* Store allocated handle here */
2992   int rc;                         /* Return code */
2993   int isThreadsafe;               /* True for threadsafe connections */
2994   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2995   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2996 
2997 #ifdef SQLITE_ENABLE_API_ARMOR
2998   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2999 #endif
3000   *ppDb = 0;
3001 #ifndef SQLITE_OMIT_AUTOINIT
3002   rc = sqlite3_initialize();
3003   if( rc ) return rc;
3004 #endif
3005 
3006   if( sqlite3GlobalConfig.bCoreMutex==0 ){
3007     isThreadsafe = 0;
3008   }else if( flags & SQLITE_OPEN_NOMUTEX ){
3009     isThreadsafe = 0;
3010   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
3011     isThreadsafe = 1;
3012   }else{
3013     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
3014   }
3015 
3016   if( flags & SQLITE_OPEN_PRIVATECACHE ){
3017     flags &= ~SQLITE_OPEN_SHAREDCACHE;
3018   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
3019     flags |= SQLITE_OPEN_SHAREDCACHE;
3020   }
3021 
3022   /* Remove harmful bits from the flags parameter
3023   **
3024   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
3025   ** dealt with in the previous code block.  Besides these, the only
3026   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
3027   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
3028   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
3029   ** off all other flags.
3030   */
3031   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
3032                SQLITE_OPEN_EXCLUSIVE |
3033                SQLITE_OPEN_MAIN_DB |
3034                SQLITE_OPEN_TEMP_DB |
3035                SQLITE_OPEN_TRANSIENT_DB |
3036                SQLITE_OPEN_MAIN_JOURNAL |
3037                SQLITE_OPEN_TEMP_JOURNAL |
3038                SQLITE_OPEN_SUBJOURNAL |
3039                SQLITE_OPEN_MASTER_JOURNAL |
3040                SQLITE_OPEN_NOMUTEX |
3041                SQLITE_OPEN_FULLMUTEX |
3042                SQLITE_OPEN_WAL
3043              );
3044 
3045   /* Allocate the sqlite data structure */
3046   db = sqlite3MallocZero( sizeof(sqlite3) );
3047   if( db==0 ) goto opendb_out;
3048   if( isThreadsafe
3049 #ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS
3050    || sqlite3GlobalConfig.bCoreMutex
3051 #endif
3052   ){
3053     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
3054     if( db->mutex==0 ){
3055       sqlite3_free(db);
3056       db = 0;
3057       goto opendb_out;
3058     }
3059     if( isThreadsafe==0 ){
3060       sqlite3MutexWarnOnContention(db->mutex);
3061     }
3062   }
3063   sqlite3_mutex_enter(db->mutex);
3064   db->errMask = 0xff;
3065   db->nDb = 2;
3066   db->magic = SQLITE_MAGIC_BUSY;
3067   db->aDb = db->aDbStatic;
3068   db->lookaside.bDisable = 1;
3069 
3070   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
3071   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
3072   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
3073   db->autoCommit = 1;
3074   db->nextAutovac = -1;
3075   db->szMmap = sqlite3GlobalConfig.szMmap;
3076   db->nextPagesize = 0;
3077   db->nMaxSorterMmap = 0x7FFFFFFF;
3078   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
3079 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
3080                  | SQLITE_AutoIndex
3081 #endif
3082 #if SQLITE_DEFAULT_CKPTFULLFSYNC
3083                  | SQLITE_CkptFullFSync
3084 #endif
3085 #if SQLITE_DEFAULT_FILE_FORMAT<4
3086                  | SQLITE_LegacyFileFmt
3087 #endif
3088 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
3089                  | SQLITE_LoadExtension
3090 #endif
3091 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
3092                  | SQLITE_RecTriggers
3093 #endif
3094 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
3095                  | SQLITE_ForeignKeys
3096 #endif
3097 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
3098                  | SQLITE_ReverseOrder
3099 #endif
3100 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
3101                  | SQLITE_CellSizeCk
3102 #endif
3103 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
3104                  | SQLITE_Fts3Tokenizer
3105 #endif
3106 #if defined(SQLITE_ENABLE_QPSG)
3107                  | SQLITE_EnableQPSG
3108 #endif
3109 #if defined(SQLITE_DEFAULT_DEFENSIVE)
3110                  | SQLITE_Defensive
3111 #endif
3112       ;
3113   sqlite3HashInit(&db->aCollSeq);
3114 #ifndef SQLITE_OMIT_VIRTUALTABLE
3115   sqlite3HashInit(&db->aModule);
3116 #endif
3117 
3118   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
3119   ** and UTF-16, so add a version for each to avoid any unnecessary
3120   ** conversions. The only error that can occur here is a malloc() failure.
3121   **
3122   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
3123   ** functions:
3124   */
3125   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
3126   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
3127   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
3128   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
3129   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
3130   if( db->mallocFailed ){
3131     goto opendb_out;
3132   }
3133   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
3134   ** strings is BINARY.
3135   */
3136   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
3137   assert( db->pDfltColl!=0 );
3138 
3139   /* Parse the filename/URI argument
3140   **
3141   ** Only allow sensible combinations of bits in the flags argument.
3142   ** Throw an error if any non-sense combination is used.  If we
3143   ** do not block illegal combinations here, it could trigger
3144   ** assert() statements in deeper layers.  Sensible combinations
3145   ** are:
3146   **
3147   **  1:  SQLITE_OPEN_READONLY
3148   **  2:  SQLITE_OPEN_READWRITE
3149   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
3150   */
3151   db->openFlags = flags;
3152   assert( SQLITE_OPEN_READONLY  == 0x01 );
3153   assert( SQLITE_OPEN_READWRITE == 0x02 );
3154   assert( SQLITE_OPEN_CREATE    == 0x04 );
3155   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
3156   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
3157   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
3158   if( ((1<<(flags&7)) & 0x46)==0 ){
3159     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
3160   }else{
3161     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
3162   }
3163   if( rc!=SQLITE_OK ){
3164     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
3165     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
3166     sqlite3_free(zErrMsg);
3167     goto opendb_out;
3168   }
3169 
3170   /* Open the backend database driver */
3171   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
3172                         flags | SQLITE_OPEN_MAIN_DB);
3173   if( rc!=SQLITE_OK ){
3174     if( rc==SQLITE_IOERR_NOMEM ){
3175       rc = SQLITE_NOMEM_BKPT;
3176     }
3177     sqlite3Error(db, rc);
3178     goto opendb_out;
3179   }
3180   sqlite3BtreeEnter(db->aDb[0].pBt);
3181   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
3182   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
3183   sqlite3BtreeLeave(db->aDb[0].pBt);
3184   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
3185 
3186   /* The default safety_level for the main database is FULL; for the temp
3187   ** database it is OFF. This matches the pager layer defaults.
3188   */
3189   db->aDb[0].zDbSName = "main";
3190   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
3191   db->aDb[1].zDbSName = "temp";
3192   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
3193 
3194   db->magic = SQLITE_MAGIC_OPEN;
3195   if( db->mallocFailed ){
3196     goto opendb_out;
3197   }
3198 
3199   /* Register all built-in functions, but do not attempt to read the
3200   ** database schema yet. This is delayed until the first time the database
3201   ** is accessed.
3202   */
3203   sqlite3Error(db, SQLITE_OK);
3204   sqlite3RegisterPerConnectionBuiltinFunctions(db);
3205   rc = sqlite3_errcode(db);
3206 
3207 #ifdef SQLITE_ENABLE_FTS5
3208   /* Register any built-in FTS5 module before loading the automatic
3209   ** extensions. This allows automatic extensions to register FTS5
3210   ** tokenizers and auxiliary functions.  */
3211   if( !db->mallocFailed && rc==SQLITE_OK ){
3212     rc = sqlite3Fts5Init(db);
3213   }
3214 #endif
3215 
3216   /* Load automatic extensions - extensions that have been registered
3217   ** using the sqlite3_automatic_extension() API.
3218   */
3219   if( rc==SQLITE_OK ){
3220     sqlite3AutoLoadExtensions(db);
3221     rc = sqlite3_errcode(db);
3222     if( rc!=SQLITE_OK ){
3223       goto opendb_out;
3224     }
3225   }
3226 
3227 #ifdef SQLITE_ENABLE_FTS1
3228   if( !db->mallocFailed ){
3229     extern int sqlite3Fts1Init(sqlite3*);
3230     rc = sqlite3Fts1Init(db);
3231   }
3232 #endif
3233 
3234 #ifdef SQLITE_ENABLE_FTS2
3235   if( !db->mallocFailed && rc==SQLITE_OK ){
3236     extern int sqlite3Fts2Init(sqlite3*);
3237     rc = sqlite3Fts2Init(db);
3238   }
3239 #endif
3240 
3241 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3242   if( !db->mallocFailed && rc==SQLITE_OK ){
3243     rc = sqlite3Fts3Init(db);
3244   }
3245 #endif
3246 
3247 #if defined(SQLITE_ENABLE_ICU) || defined(SQLITE_ENABLE_ICU_COLLATIONS)
3248   if( !db->mallocFailed && rc==SQLITE_OK ){
3249     rc = sqlite3IcuInit(db);
3250   }
3251 #endif
3252 
3253 #ifdef SQLITE_ENABLE_RTREE
3254   if( !db->mallocFailed && rc==SQLITE_OK){
3255     rc = sqlite3RtreeInit(db);
3256   }
3257 #endif
3258 
3259 #ifdef SQLITE_ENABLE_DBPAGE_VTAB
3260   if( !db->mallocFailed && rc==SQLITE_OK){
3261     rc = sqlite3DbpageRegister(db);
3262   }
3263 #endif
3264 
3265 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3266   if( !db->mallocFailed && rc==SQLITE_OK){
3267     rc = sqlite3DbstatRegister(db);
3268   }
3269 #endif
3270 
3271 #ifdef SQLITE_ENABLE_JSON1
3272   if( !db->mallocFailed && rc==SQLITE_OK){
3273     rc = sqlite3Json1Init(db);
3274   }
3275 #endif
3276 
3277 #ifdef SQLITE_ENABLE_STMTVTAB
3278   if( !db->mallocFailed && rc==SQLITE_OK){
3279     rc = sqlite3StmtVtabInit(db);
3280   }
3281 #endif
3282 
3283   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3284   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3285   ** mode.  Doing nothing at all also makes NORMAL the default.
3286   */
3287 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3288   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3289   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3290                           SQLITE_DEFAULT_LOCKING_MODE);
3291 #endif
3292 
3293   if( rc ) sqlite3Error(db, rc);
3294 
3295   /* Enable the lookaside-malloc subsystem */
3296   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3297                         sqlite3GlobalConfig.nLookaside);
3298 
3299   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3300 
3301 opendb_out:
3302   if( db ){
3303     assert( db->mutex!=0 || isThreadsafe==0
3304            || sqlite3GlobalConfig.bFullMutex==0 );
3305     sqlite3_mutex_leave(db->mutex);
3306   }
3307   rc = sqlite3_errcode(db);
3308   assert( db!=0 || rc==SQLITE_NOMEM );
3309   if( rc==SQLITE_NOMEM ){
3310     sqlite3_close(db);
3311     db = 0;
3312   }else if( rc!=SQLITE_OK ){
3313     db->magic = SQLITE_MAGIC_SICK;
3314   }
3315   *ppDb = db;
3316 #ifdef SQLITE_ENABLE_SQLLOG
3317   if( sqlite3GlobalConfig.xSqllog ){
3318     /* Opening a db handle. Fourth parameter is passed 0. */
3319     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3320     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3321   }
3322 #endif
3323 #if defined(SQLITE_HAS_CODEC)
3324   if( rc==SQLITE_OK ) sqlite3CodecQueryParameters(db, 0, zOpen);
3325 #endif
3326   sqlite3_free(zOpen);
3327   return rc & 0xff;
3328 }
3329 
3330 
3331 /*
3332 ** Open a new database handle.
3333 */
3334 int sqlite3_open(
3335   const char *zFilename,
3336   sqlite3 **ppDb
3337 ){
3338   return openDatabase(zFilename, ppDb,
3339                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3340 }
3341 int sqlite3_open_v2(
3342   const char *filename,   /* Database filename (UTF-8) */
3343   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3344   int flags,              /* Flags */
3345   const char *zVfs        /* Name of VFS module to use */
3346 ){
3347   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3348 }
3349 
3350 #ifndef SQLITE_OMIT_UTF16
3351 /*
3352 ** Open a new database handle.
3353 */
3354 int sqlite3_open16(
3355   const void *zFilename,
3356   sqlite3 **ppDb
3357 ){
3358   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3359   sqlite3_value *pVal;
3360   int rc;
3361 
3362 #ifdef SQLITE_ENABLE_API_ARMOR
3363   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3364 #endif
3365   *ppDb = 0;
3366 #ifndef SQLITE_OMIT_AUTOINIT
3367   rc = sqlite3_initialize();
3368   if( rc ) return rc;
3369 #endif
3370   if( zFilename==0 ) zFilename = "\000\000";
3371   pVal = sqlite3ValueNew(0);
3372   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3373   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3374   if( zFilename8 ){
3375     rc = openDatabase(zFilename8, ppDb,
3376                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3377     assert( *ppDb || rc==SQLITE_NOMEM );
3378     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3379       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3380     }
3381   }else{
3382     rc = SQLITE_NOMEM_BKPT;
3383   }
3384   sqlite3ValueFree(pVal);
3385 
3386   return rc & 0xff;
3387 }
3388 #endif /* SQLITE_OMIT_UTF16 */
3389 
3390 /*
3391 ** Register a new collation sequence with the database handle db.
3392 */
3393 int sqlite3_create_collation(
3394   sqlite3* db,
3395   const char *zName,
3396   int enc,
3397   void* pCtx,
3398   int(*xCompare)(void*,int,const void*,int,const void*)
3399 ){
3400   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3401 }
3402 
3403 /*
3404 ** Register a new collation sequence with the database handle db.
3405 */
3406 int sqlite3_create_collation_v2(
3407   sqlite3* db,
3408   const char *zName,
3409   int enc,
3410   void* pCtx,
3411   int(*xCompare)(void*,int,const void*,int,const void*),
3412   void(*xDel)(void*)
3413 ){
3414   int rc;
3415 
3416 #ifdef SQLITE_ENABLE_API_ARMOR
3417   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3418 #endif
3419   sqlite3_mutex_enter(db->mutex);
3420   assert( !db->mallocFailed );
3421   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3422   rc = sqlite3ApiExit(db, rc);
3423   sqlite3_mutex_leave(db->mutex);
3424   return rc;
3425 }
3426 
3427 #ifndef SQLITE_OMIT_UTF16
3428 /*
3429 ** Register a new collation sequence with the database handle db.
3430 */
3431 int sqlite3_create_collation16(
3432   sqlite3* db,
3433   const void *zName,
3434   int enc,
3435   void* pCtx,
3436   int(*xCompare)(void*,int,const void*,int,const void*)
3437 ){
3438   int rc = SQLITE_OK;
3439   char *zName8;
3440 
3441 #ifdef SQLITE_ENABLE_API_ARMOR
3442   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3443 #endif
3444   sqlite3_mutex_enter(db->mutex);
3445   assert( !db->mallocFailed );
3446   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3447   if( zName8 ){
3448     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3449     sqlite3DbFree(db, zName8);
3450   }
3451   rc = sqlite3ApiExit(db, rc);
3452   sqlite3_mutex_leave(db->mutex);
3453   return rc;
3454 }
3455 #endif /* SQLITE_OMIT_UTF16 */
3456 
3457 /*
3458 ** Register a collation sequence factory callback with the database handle
3459 ** db. Replace any previously installed collation sequence factory.
3460 */
3461 int sqlite3_collation_needed(
3462   sqlite3 *db,
3463   void *pCollNeededArg,
3464   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3465 ){
3466 #ifdef SQLITE_ENABLE_API_ARMOR
3467   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3468 #endif
3469   sqlite3_mutex_enter(db->mutex);
3470   db->xCollNeeded = xCollNeeded;
3471   db->xCollNeeded16 = 0;
3472   db->pCollNeededArg = pCollNeededArg;
3473   sqlite3_mutex_leave(db->mutex);
3474   return SQLITE_OK;
3475 }
3476 
3477 #ifndef SQLITE_OMIT_UTF16
3478 /*
3479 ** Register a collation sequence factory callback with the database handle
3480 ** db. Replace any previously installed collation sequence factory.
3481 */
3482 int sqlite3_collation_needed16(
3483   sqlite3 *db,
3484   void *pCollNeededArg,
3485   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3486 ){
3487 #ifdef SQLITE_ENABLE_API_ARMOR
3488   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3489 #endif
3490   sqlite3_mutex_enter(db->mutex);
3491   db->xCollNeeded = 0;
3492   db->xCollNeeded16 = xCollNeeded16;
3493   db->pCollNeededArg = pCollNeededArg;
3494   sqlite3_mutex_leave(db->mutex);
3495   return SQLITE_OK;
3496 }
3497 #endif /* SQLITE_OMIT_UTF16 */
3498 
3499 #ifndef SQLITE_OMIT_DEPRECATED
3500 /*
3501 ** This function is now an anachronism. It used to be used to recover from a
3502 ** malloc() failure, but SQLite now does this automatically.
3503 */
3504 int sqlite3_global_recover(void){
3505   return SQLITE_OK;
3506 }
3507 #endif
3508 
3509 /*
3510 ** Test to see whether or not the database connection is in autocommit
3511 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3512 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3513 ** by the next COMMIT or ROLLBACK.
3514 */
3515 int sqlite3_get_autocommit(sqlite3 *db){
3516 #ifdef SQLITE_ENABLE_API_ARMOR
3517   if( !sqlite3SafetyCheckOk(db) ){
3518     (void)SQLITE_MISUSE_BKPT;
3519     return 0;
3520   }
3521 #endif
3522   return db->autoCommit;
3523 }
3524 
3525 /*
3526 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3527 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3528 ** constants.  They serve two purposes:
3529 **
3530 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3531 **       to detect when version error conditions occurs.
3532 **
3533 **   2.  Invoke sqlite3_log() to provide the source code location where
3534 **       a low-level error is first detected.
3535 */
3536 int sqlite3ReportError(int iErr, int lineno, const char *zType){
3537   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3538               zType, lineno, 20+sqlite3_sourceid());
3539   return iErr;
3540 }
3541 int sqlite3CorruptError(int lineno){
3542   testcase( sqlite3GlobalConfig.xLog!=0 );
3543   return sqlite3ReportError(SQLITE_CORRUPT, lineno, "database corruption");
3544 }
3545 int sqlite3MisuseError(int lineno){
3546   testcase( sqlite3GlobalConfig.xLog!=0 );
3547   return sqlite3ReportError(SQLITE_MISUSE, lineno, "misuse");
3548 }
3549 int sqlite3CantopenError(int lineno){
3550   testcase( sqlite3GlobalConfig.xLog!=0 );
3551   return sqlite3ReportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3552 }
3553 #ifdef SQLITE_DEBUG
3554 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3555   char zMsg[100];
3556   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3557   testcase( sqlite3GlobalConfig.xLog!=0 );
3558   return sqlite3ReportError(SQLITE_CORRUPT, lineno, zMsg);
3559 }
3560 int sqlite3NomemError(int lineno){
3561   testcase( sqlite3GlobalConfig.xLog!=0 );
3562   return sqlite3ReportError(SQLITE_NOMEM, lineno, "OOM");
3563 }
3564 int sqlite3IoerrnomemError(int lineno){
3565   testcase( sqlite3GlobalConfig.xLog!=0 );
3566   return sqlite3ReportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3567 }
3568 #endif
3569 
3570 #ifndef SQLITE_OMIT_DEPRECATED
3571 /*
3572 ** This is a convenience routine that makes sure that all thread-specific
3573 ** data for this thread has been deallocated.
3574 **
3575 ** SQLite no longer uses thread-specific data so this routine is now a
3576 ** no-op.  It is retained for historical compatibility.
3577 */
3578 void sqlite3_thread_cleanup(void){
3579 }
3580 #endif
3581 
3582 /*
3583 ** Return meta information about a specific column of a database table.
3584 ** See comment in sqlite3.h (sqlite.h.in) for details.
3585 */
3586 int sqlite3_table_column_metadata(
3587   sqlite3 *db,                /* Connection handle */
3588   const char *zDbName,        /* Database name or NULL */
3589   const char *zTableName,     /* Table name */
3590   const char *zColumnName,    /* Column name */
3591   char const **pzDataType,    /* OUTPUT: Declared data type */
3592   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3593   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3594   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3595   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3596 ){
3597   int rc;
3598   char *zErrMsg = 0;
3599   Table *pTab = 0;
3600   Column *pCol = 0;
3601   int iCol = 0;
3602   char const *zDataType = 0;
3603   char const *zCollSeq = 0;
3604   int notnull = 0;
3605   int primarykey = 0;
3606   int autoinc = 0;
3607 
3608 
3609 #ifdef SQLITE_ENABLE_API_ARMOR
3610   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3611     return SQLITE_MISUSE_BKPT;
3612   }
3613 #endif
3614 
3615   /* Ensure the database schema has been loaded */
3616   sqlite3_mutex_enter(db->mutex);
3617   sqlite3BtreeEnterAll(db);
3618   rc = sqlite3Init(db, &zErrMsg);
3619   if( SQLITE_OK!=rc ){
3620     goto error_out;
3621   }
3622 
3623   /* Locate the table in question */
3624   pTab = sqlite3FindTable(db, zTableName, zDbName);
3625   if( !pTab || pTab->pSelect ){
3626     pTab = 0;
3627     goto error_out;
3628   }
3629 
3630   /* Find the column for which info is requested */
3631   if( zColumnName==0 ){
3632     /* Query for existance of table only */
3633   }else{
3634     for(iCol=0; iCol<pTab->nCol; iCol++){
3635       pCol = &pTab->aCol[iCol];
3636       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3637         break;
3638       }
3639     }
3640     if( iCol==pTab->nCol ){
3641       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3642         iCol = pTab->iPKey;
3643         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3644       }else{
3645         pTab = 0;
3646         goto error_out;
3647       }
3648     }
3649   }
3650 
3651   /* The following block stores the meta information that will be returned
3652   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3653   ** and autoinc. At this point there are two possibilities:
3654   **
3655   **     1. The specified column name was rowid", "oid" or "_rowid_"
3656   **        and there is no explicitly declared IPK column.
3657   **
3658   **     2. The table is not a view and the column name identified an
3659   **        explicitly declared column. Copy meta information from *pCol.
3660   */
3661   if( pCol ){
3662     zDataType = sqlite3ColumnType(pCol,0);
3663     zCollSeq = pCol->zColl;
3664     notnull = pCol->notNull!=0;
3665     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3666     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3667   }else{
3668     zDataType = "INTEGER";
3669     primarykey = 1;
3670   }
3671   if( !zCollSeq ){
3672     zCollSeq = sqlite3StrBINARY;
3673   }
3674 
3675 error_out:
3676   sqlite3BtreeLeaveAll(db);
3677 
3678   /* Whether the function call succeeded or failed, set the output parameters
3679   ** to whatever their local counterparts contain. If an error did occur,
3680   ** this has the effect of zeroing all output parameters.
3681   */
3682   if( pzDataType ) *pzDataType = zDataType;
3683   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3684   if( pNotNull ) *pNotNull = notnull;
3685   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3686   if( pAutoinc ) *pAutoinc = autoinc;
3687 
3688   if( SQLITE_OK==rc && !pTab ){
3689     sqlite3DbFree(db, zErrMsg);
3690     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3691         zColumnName);
3692     rc = SQLITE_ERROR;
3693   }
3694   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3695   sqlite3DbFree(db, zErrMsg);
3696   rc = sqlite3ApiExit(db, rc);
3697   sqlite3_mutex_leave(db->mutex);
3698   return rc;
3699 }
3700 
3701 /*
3702 ** Sleep for a little while.  Return the amount of time slept.
3703 */
3704 int sqlite3_sleep(int ms){
3705   sqlite3_vfs *pVfs;
3706   int rc;
3707   pVfs = sqlite3_vfs_find(0);
3708   if( pVfs==0 ) return 0;
3709 
3710   /* This function works in milliseconds, but the underlying OsSleep()
3711   ** API uses microseconds. Hence the 1000's.
3712   */
3713   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3714   return rc;
3715 }
3716 
3717 /*
3718 ** Enable or disable the extended result codes.
3719 */
3720 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3721 #ifdef SQLITE_ENABLE_API_ARMOR
3722   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3723 #endif
3724   sqlite3_mutex_enter(db->mutex);
3725   db->errMask = onoff ? 0xffffffff : 0xff;
3726   sqlite3_mutex_leave(db->mutex);
3727   return SQLITE_OK;
3728 }
3729 
3730 /*
3731 ** Invoke the xFileControl method on a particular database.
3732 */
3733 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3734   int rc = SQLITE_ERROR;
3735   Btree *pBtree;
3736 
3737 #ifdef SQLITE_ENABLE_API_ARMOR
3738   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3739 #endif
3740   sqlite3_mutex_enter(db->mutex);
3741   pBtree = sqlite3DbNameToBtree(db, zDbName);
3742   if( pBtree ){
3743     Pager *pPager;
3744     sqlite3_file *fd;
3745     sqlite3BtreeEnter(pBtree);
3746     pPager = sqlite3BtreePager(pBtree);
3747     assert( pPager!=0 );
3748     fd = sqlite3PagerFile(pPager);
3749     assert( fd!=0 );
3750     if( op==SQLITE_FCNTL_FILE_POINTER ){
3751       *(sqlite3_file**)pArg = fd;
3752       rc = SQLITE_OK;
3753     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3754       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3755       rc = SQLITE_OK;
3756     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3757       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3758       rc = SQLITE_OK;
3759     }else if( op==SQLITE_FCNTL_DATA_VERSION ){
3760       *(unsigned int*)pArg = sqlite3PagerDataVersion(pPager);
3761       rc = SQLITE_OK;
3762     }else{
3763       rc = sqlite3OsFileControl(fd, op, pArg);
3764     }
3765     sqlite3BtreeLeave(pBtree);
3766   }
3767   sqlite3_mutex_leave(db->mutex);
3768   return rc;
3769 }
3770 
3771 /*
3772 ** Interface to the testing logic.
3773 */
3774 int sqlite3_test_control(int op, ...){
3775   int rc = 0;
3776 #ifdef SQLITE_UNTESTABLE
3777   UNUSED_PARAMETER(op);
3778 #else
3779   va_list ap;
3780   va_start(ap, op);
3781   switch( op ){
3782 
3783     /*
3784     ** Save the current state of the PRNG.
3785     */
3786     case SQLITE_TESTCTRL_PRNG_SAVE: {
3787       sqlite3PrngSaveState();
3788       break;
3789     }
3790 
3791     /*
3792     ** Restore the state of the PRNG to the last state saved using
3793     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3794     ** this verb acts like PRNG_RESET.
3795     */
3796     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3797       sqlite3PrngRestoreState();
3798       break;
3799     }
3800 
3801     /*
3802     ** Reset the PRNG back to its uninitialized state.  The next call
3803     ** to sqlite3_randomness() will reseed the PRNG using a single call
3804     ** to the xRandomness method of the default VFS.
3805     */
3806     case SQLITE_TESTCTRL_PRNG_RESET: {
3807       sqlite3_randomness(0,0);
3808       break;
3809     }
3810 
3811     /*
3812     **  sqlite3_test_control(BITVEC_TEST, size, program)
3813     **
3814     ** Run a test against a Bitvec object of size.  The program argument
3815     ** is an array of integers that defines the test.  Return -1 on a
3816     ** memory allocation error, 0 on success, or non-zero for an error.
3817     ** See the sqlite3BitvecBuiltinTest() for additional information.
3818     */
3819     case SQLITE_TESTCTRL_BITVEC_TEST: {
3820       int sz = va_arg(ap, int);
3821       int *aProg = va_arg(ap, int*);
3822       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3823       break;
3824     }
3825 
3826     /*
3827     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3828     **
3829     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3830     ** if xCallback is not NULL.
3831     **
3832     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3833     ** is called immediately after installing the new callback and the return
3834     ** value from sqlite3FaultSim(0) becomes the return from
3835     ** sqlite3_test_control().
3836     */
3837     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3838       /* MSVC is picky about pulling func ptrs from va lists.
3839       ** http://support.microsoft.com/kb/47961
3840       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3841       */
3842       typedef int(*TESTCALLBACKFUNC_t)(int);
3843       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3844       rc = sqlite3FaultSim(0);
3845       break;
3846     }
3847 
3848     /*
3849     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3850     **
3851     ** Register hooks to call to indicate which malloc() failures
3852     ** are benign.
3853     */
3854     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3855       typedef void (*void_function)(void);
3856       void_function xBenignBegin;
3857       void_function xBenignEnd;
3858       xBenignBegin = va_arg(ap, void_function);
3859       xBenignEnd = va_arg(ap, void_function);
3860       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3861       break;
3862     }
3863 
3864     /*
3865     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3866     **
3867     ** Set the PENDING byte to the value in the argument, if X>0.
3868     ** Make no changes if X==0.  Return the value of the pending byte
3869     ** as it existing before this routine was called.
3870     **
3871     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3872     ** an incompatible database file format.  Changing the PENDING byte
3873     ** while any database connection is open results in undefined and
3874     ** deleterious behavior.
3875     */
3876     case SQLITE_TESTCTRL_PENDING_BYTE: {
3877       rc = PENDING_BYTE;
3878 #ifndef SQLITE_OMIT_WSD
3879       {
3880         unsigned int newVal = va_arg(ap, unsigned int);
3881         if( newVal ) sqlite3PendingByte = newVal;
3882       }
3883 #endif
3884       break;
3885     }
3886 
3887     /*
3888     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3889     **
3890     ** This action provides a run-time test to see whether or not
3891     ** assert() was enabled at compile-time.  If X is true and assert()
3892     ** is enabled, then the return value is true.  If X is true and
3893     ** assert() is disabled, then the return value is zero.  If X is
3894     ** false and assert() is enabled, then the assertion fires and the
3895     ** process aborts.  If X is false and assert() is disabled, then the
3896     ** return value is zero.
3897     */
3898     case SQLITE_TESTCTRL_ASSERT: {
3899       volatile int x = 0;
3900       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3901       rc = x;
3902       break;
3903     }
3904 
3905 
3906     /*
3907     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3908     **
3909     ** This action provides a run-time test to see how the ALWAYS and
3910     ** NEVER macros were defined at compile-time.
3911     **
3912     ** The return value is ALWAYS(X) if X is true, or 0 if X is false.
3913     **
3914     ** The recommended test is X==2.  If the return value is 2, that means
3915     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3916     ** default setting.  If the return value is 1, then ALWAYS() is either
3917     ** hard-coded to true or else it asserts if its argument is false.
3918     ** The first behavior (hard-coded to true) is the case if
3919     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3920     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3921     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3922     **
3923     ** The run-time test procedure might look something like this:
3924     **
3925     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3926     **      // ALWAYS() and NEVER() are no-op pass-through macros
3927     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3928     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3929     **    }else{
3930     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3931     **    }
3932     */
3933     case SQLITE_TESTCTRL_ALWAYS: {
3934       int x = va_arg(ap,int);
3935       rc = x ? ALWAYS(x) : 0;
3936       break;
3937     }
3938 
3939     /*
3940     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3941     **
3942     ** The integer returned reveals the byte-order of the computer on which
3943     ** SQLite is running:
3944     **
3945     **       1     big-endian,    determined at run-time
3946     **      10     little-endian, determined at run-time
3947     **  432101     big-endian,    determined at compile-time
3948     **  123410     little-endian, determined at compile-time
3949     */
3950     case SQLITE_TESTCTRL_BYTEORDER: {
3951       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3952       break;
3953     }
3954 
3955     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3956     **
3957     ** Set the nReserve size to N for the main database on the database
3958     ** connection db.
3959     */
3960     case SQLITE_TESTCTRL_RESERVE: {
3961       sqlite3 *db = va_arg(ap, sqlite3*);
3962       int x = va_arg(ap,int);
3963       sqlite3_mutex_enter(db->mutex);
3964       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3965       sqlite3_mutex_leave(db->mutex);
3966       break;
3967     }
3968 
3969     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3970     **
3971     ** Enable or disable various optimizations for testing purposes.  The
3972     ** argument N is a bitmask of optimizations to be disabled.  For normal
3973     ** operation N should be 0.  The idea is that a test program (like the
3974     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3975     ** with various optimizations disabled to verify that the same answer
3976     ** is obtained in every case.
3977     */
3978     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3979       sqlite3 *db = va_arg(ap, sqlite3*);
3980       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3981       break;
3982     }
3983 
3984     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3985     **
3986     ** If parameter onoff is non-zero, subsequent calls to localtime()
3987     ** and its variants fail. If onoff is zero, undo this setting.
3988     */
3989     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3990       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3991       break;
3992     }
3993 
3994     /*   sqlite3_test_control(SQLITE_TESTCTRL_INTERNAL_FUNCS, int onoff);
3995     **
3996     ** If parameter onoff is non-zero, internal-use-only SQL functions
3997     ** are visible to ordinary SQL.  This is useful for testing but is
3998     ** unsafe because invalid parameters to those internal-use-only functions
3999     ** can result in crashes or segfaults.
4000     */
4001     case SQLITE_TESTCTRL_INTERNAL_FUNCTIONS: {
4002       sqlite3GlobalConfig.bInternalFunctions = va_arg(ap, int);
4003       break;
4004     }
4005 
4006     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
4007     **
4008     ** Set or clear a flag that indicates that the database file is always well-
4009     ** formed and never corrupt.  This flag is clear by default, indicating that
4010     ** database files might have arbitrary corruption.  Setting the flag during
4011     ** testing causes certain assert() statements in the code to be activated
4012     ** that demonstrat invariants on well-formed database files.
4013     */
4014     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
4015       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
4016       break;
4017     }
4018 
4019     /* Set the threshold at which OP_Once counters reset back to zero.
4020     ** By default this is 0x7ffffffe (over 2 billion), but that value is
4021     ** too big to test in a reasonable amount of time, so this control is
4022     ** provided to set a small and easily reachable reset value.
4023     */
4024     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
4025       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
4026       break;
4027     }
4028 
4029     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
4030     **
4031     ** Set the VDBE coverage callback function to xCallback with context
4032     ** pointer ptr.
4033     */
4034     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
4035 #ifdef SQLITE_VDBE_COVERAGE
4036       typedef void (*branch_callback)(void*,unsigned int,
4037                                       unsigned char,unsigned char);
4038       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
4039       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
4040 #endif
4041       break;
4042     }
4043 
4044     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
4045     case SQLITE_TESTCTRL_SORTER_MMAP: {
4046       sqlite3 *db = va_arg(ap, sqlite3*);
4047       db->nMaxSorterMmap = va_arg(ap, int);
4048       break;
4049     }
4050 
4051     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
4052     **
4053     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
4054     ** not.
4055     */
4056     case SQLITE_TESTCTRL_ISINIT: {
4057       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
4058       break;
4059     }
4060 
4061     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
4062     **
4063     ** This test control is used to create imposter tables.  "db" is a pointer
4064     ** to the database connection.  dbName is the database name (ex: "main" or
4065     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
4066     ** or off.  "tnum" is the root page of the b-tree to which the imposter
4067     ** table should connect.
4068     **
4069     ** Enable imposter mode only when the schema has already been parsed.  Then
4070     ** run a single CREATE TABLE statement to construct the imposter table in
4071     ** the parsed schema.  Then turn imposter mode back off again.
4072     **
4073     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
4074     ** the schema to be reparsed the next time it is needed.  This has the
4075     ** effect of erasing all imposter tables.
4076     */
4077     case SQLITE_TESTCTRL_IMPOSTER: {
4078       sqlite3 *db = va_arg(ap, sqlite3*);
4079       sqlite3_mutex_enter(db->mutex);
4080       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
4081       db->init.busy = db->init.imposterTable = va_arg(ap,int);
4082       db->init.newTnum = va_arg(ap,int);
4083       if( db->init.busy==0 && db->init.newTnum>0 ){
4084         sqlite3ResetAllSchemasOfConnection(db);
4085       }
4086       sqlite3_mutex_leave(db->mutex);
4087       break;
4088     }
4089 
4090 #if defined(YYCOVERAGE)
4091     /*  sqlite3_test_control(SQLITE_TESTCTRL_PARSER_COVERAGE, FILE *out)
4092     **
4093     ** This test control (only available when SQLite is compiled with
4094     ** -DYYCOVERAGE) writes a report onto "out" that shows all
4095     ** state/lookahead combinations in the parser state machine
4096     ** which are never exercised.  If any state is missed, make the
4097     ** return code SQLITE_ERROR.
4098     */
4099     case SQLITE_TESTCTRL_PARSER_COVERAGE: {
4100       FILE *out = va_arg(ap, FILE*);
4101       if( sqlite3ParserCoverage(out) ) rc = SQLITE_ERROR;
4102       break;
4103     }
4104 #endif /* defined(YYCOVERAGE) */
4105   }
4106   va_end(ap);
4107 #endif /* SQLITE_UNTESTABLE */
4108   return rc;
4109 }
4110 
4111 /*
4112 ** This is a utility routine, useful to VFS implementations, that checks
4113 ** to see if a database file was a URI that contained a specific query
4114 ** parameter, and if so obtains the value of the query parameter.
4115 **
4116 ** The zFilename argument is the filename pointer passed into the xOpen()
4117 ** method of a VFS implementation.  The zParam argument is the name of the
4118 ** query parameter we seek.  This routine returns the value of the zParam
4119 ** parameter if it exists.  If the parameter does not exist, this routine
4120 ** returns a NULL pointer.
4121 */
4122 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
4123   if( zFilename==0 || zParam==0 ) return 0;
4124   zFilename += sqlite3Strlen30(zFilename) + 1;
4125   while( zFilename[0] ){
4126     int x = strcmp(zFilename, zParam);
4127     zFilename += sqlite3Strlen30(zFilename) + 1;
4128     if( x==0 ) return zFilename;
4129     zFilename += sqlite3Strlen30(zFilename) + 1;
4130   }
4131   return 0;
4132 }
4133 
4134 /*
4135 ** Return a boolean value for a query parameter.
4136 */
4137 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
4138   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4139   bDflt = bDflt!=0;
4140   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
4141 }
4142 
4143 /*
4144 ** Return a 64-bit integer value for a query parameter.
4145 */
4146 sqlite3_int64 sqlite3_uri_int64(
4147   const char *zFilename,    /* Filename as passed to xOpen */
4148   const char *zParam,       /* URI parameter sought */
4149   sqlite3_int64 bDflt       /* return if parameter is missing */
4150 ){
4151   const char *z = sqlite3_uri_parameter(zFilename, zParam);
4152   sqlite3_int64 v;
4153   if( z && sqlite3DecOrHexToI64(z, &v)==0 ){
4154     bDflt = v;
4155   }
4156   return bDflt;
4157 }
4158 
4159 /*
4160 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
4161 */
4162 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
4163   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
4164   return iDb<0 ? 0 : db->aDb[iDb].pBt;
4165 }
4166 
4167 /*
4168 ** Return the filename of the database associated with a database
4169 ** connection.
4170 */
4171 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
4172   Btree *pBt;
4173 #ifdef SQLITE_ENABLE_API_ARMOR
4174   if( !sqlite3SafetyCheckOk(db) ){
4175     (void)SQLITE_MISUSE_BKPT;
4176     return 0;
4177   }
4178 #endif
4179   pBt = sqlite3DbNameToBtree(db, zDbName);
4180   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
4181 }
4182 
4183 /*
4184 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
4185 ** no such database exists.
4186 */
4187 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
4188   Btree *pBt;
4189 #ifdef SQLITE_ENABLE_API_ARMOR
4190   if( !sqlite3SafetyCheckOk(db) ){
4191     (void)SQLITE_MISUSE_BKPT;
4192     return -1;
4193   }
4194 #endif
4195   pBt = sqlite3DbNameToBtree(db, zDbName);
4196   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
4197 }
4198 
4199 #ifdef SQLITE_ENABLE_SNAPSHOT
4200 /*
4201 ** Obtain a snapshot handle for the snapshot of database zDb currently
4202 ** being read by handle db.
4203 */
4204 int sqlite3_snapshot_get(
4205   sqlite3 *db,
4206   const char *zDb,
4207   sqlite3_snapshot **ppSnapshot
4208 ){
4209   int rc = SQLITE_ERROR;
4210 #ifndef SQLITE_OMIT_WAL
4211 
4212 #ifdef SQLITE_ENABLE_API_ARMOR
4213   if( !sqlite3SafetyCheckOk(db) ){
4214     return SQLITE_MISUSE_BKPT;
4215   }
4216 #endif
4217   sqlite3_mutex_enter(db->mutex);
4218 
4219   if( db->autoCommit==0 ){
4220     int iDb = sqlite3FindDbName(db, zDb);
4221     if( iDb==0 || iDb>1 ){
4222       Btree *pBt = db->aDb[iDb].pBt;
4223       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4224         rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4225         if( rc==SQLITE_OK ){
4226           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4227         }
4228       }
4229     }
4230   }
4231 
4232   sqlite3_mutex_leave(db->mutex);
4233 #endif   /* SQLITE_OMIT_WAL */
4234   return rc;
4235 }
4236 
4237 /*
4238 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4239 */
4240 int sqlite3_snapshot_open(
4241   sqlite3 *db,
4242   const char *zDb,
4243   sqlite3_snapshot *pSnapshot
4244 ){
4245   int rc = SQLITE_ERROR;
4246 #ifndef SQLITE_OMIT_WAL
4247 
4248 #ifdef SQLITE_ENABLE_API_ARMOR
4249   if( !sqlite3SafetyCheckOk(db) ){
4250     return SQLITE_MISUSE_BKPT;
4251   }
4252 #endif
4253   sqlite3_mutex_enter(db->mutex);
4254   if( db->autoCommit==0 ){
4255     int iDb;
4256     iDb = sqlite3FindDbName(db, zDb);
4257     if( iDb==0 || iDb>1 ){
4258       Btree *pBt = db->aDb[iDb].pBt;
4259       if( sqlite3BtreeIsInTrans(pBt)==0 ){
4260         Pager *pPager = sqlite3BtreePager(pBt);
4261         int bUnlock = 0;
4262         if( sqlite3BtreeIsInReadTrans(pBt) ){
4263           if( db->nVdbeActive==0 ){
4264             rc = sqlite3PagerSnapshotCheck(pPager, pSnapshot);
4265             if( rc==SQLITE_OK ){
4266               bUnlock = 1;
4267               rc = sqlite3BtreeCommit(pBt);
4268             }
4269           }
4270         }else{
4271           rc = SQLITE_OK;
4272         }
4273         if( rc==SQLITE_OK ){
4274           rc = sqlite3PagerSnapshotOpen(pPager, pSnapshot);
4275         }
4276         if( rc==SQLITE_OK ){
4277           rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4278           sqlite3PagerSnapshotOpen(pPager, 0);
4279         }
4280         if( bUnlock ){
4281           sqlite3PagerSnapshotUnlock(pPager);
4282         }
4283       }
4284     }
4285   }
4286 
4287   sqlite3_mutex_leave(db->mutex);
4288 #endif   /* SQLITE_OMIT_WAL */
4289   return rc;
4290 }
4291 
4292 /*
4293 ** Recover as many snapshots as possible from the wal file associated with
4294 ** schema zDb of database db.
4295 */
4296 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4297   int rc = SQLITE_ERROR;
4298   int iDb;
4299 #ifndef SQLITE_OMIT_WAL
4300 
4301 #ifdef SQLITE_ENABLE_API_ARMOR
4302   if( !sqlite3SafetyCheckOk(db) ){
4303     return SQLITE_MISUSE_BKPT;
4304   }
4305 #endif
4306 
4307   sqlite3_mutex_enter(db->mutex);
4308   iDb = sqlite3FindDbName(db, zDb);
4309   if( iDb==0 || iDb>1 ){
4310     Btree *pBt = db->aDb[iDb].pBt;
4311     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4312       rc = sqlite3BtreeBeginTrans(pBt, 0, 0);
4313       if( rc==SQLITE_OK ){
4314         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4315         sqlite3BtreeCommit(pBt);
4316       }
4317     }
4318   }
4319   sqlite3_mutex_leave(db->mutex);
4320 #endif   /* SQLITE_OMIT_WAL */
4321   return rc;
4322 }
4323 
4324 /*
4325 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4326 */
4327 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4328   sqlite3_free(pSnapshot);
4329 }
4330 #endif /* SQLITE_ENABLE_SNAPSHOT */
4331 
4332 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4333 /*
4334 ** Given the name of a compile-time option, return true if that option
4335 ** was used and false if not.
4336 **
4337 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4338 ** is not required for a match.
4339 */
4340 int sqlite3_compileoption_used(const char *zOptName){
4341   int i, n;
4342   int nOpt;
4343   const char **azCompileOpt;
4344 
4345 #if SQLITE_ENABLE_API_ARMOR
4346   if( zOptName==0 ){
4347     (void)SQLITE_MISUSE_BKPT;
4348     return 0;
4349   }
4350 #endif
4351 
4352   azCompileOpt = sqlite3CompileOptions(&nOpt);
4353 
4354   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4355   n = sqlite3Strlen30(zOptName);
4356 
4357   /* Since nOpt is normally in single digits, a linear search is
4358   ** adequate. No need for a binary search. */
4359   for(i=0; i<nOpt; i++){
4360     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4361      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4362     ){
4363       return 1;
4364     }
4365   }
4366   return 0;
4367 }
4368 
4369 /*
4370 ** Return the N-th compile-time option string.  If N is out of range,
4371 ** return a NULL pointer.
4372 */
4373 const char *sqlite3_compileoption_get(int N){
4374   int nOpt;
4375   const char **azCompileOpt;
4376   azCompileOpt = sqlite3CompileOptions(&nOpt);
4377   if( N>=0 && N<nOpt ){
4378     return azCompileOpt[N];
4379   }
4380   return 0;
4381 }
4382 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4383