xref: /sqlite-3.40.0/src/main.c (revision 1d91e9f2)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Main file for the SQLite library.  The routines in this file
13 ** implement the programmer interface to the library.  Routines in
14 ** other files are for internal use by SQLite and should not be
15 ** accessed by users of the library.
16 */
17 #include "sqliteInt.h"
18 
19 #ifdef SQLITE_ENABLE_FTS3
20 # include "fts3.h"
21 #endif
22 #ifdef SQLITE_ENABLE_RTREE
23 # include "rtree.h"
24 #endif
25 #ifdef SQLITE_ENABLE_ICU
26 # include "sqliteicu.h"
27 #endif
28 #ifdef SQLITE_ENABLE_JSON1
29 int sqlite3Json1Init(sqlite3*);
30 #endif
31 #ifdef SQLITE_ENABLE_STMTVTAB
32 int sqlite3StmtVtabInit(sqlite3*);
33 #endif
34 #ifdef SQLITE_ENABLE_FTS5
35 int sqlite3Fts5Init(sqlite3*);
36 #endif
37 
38 #ifndef SQLITE_AMALGAMATION
39 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
40 ** contains the text of SQLITE_VERSION macro.
41 */
42 const char sqlite3_version[] = SQLITE_VERSION;
43 #endif
44 
45 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
46 ** a pointer to the to the sqlite3_version[] string constant.
47 */
48 const char *sqlite3_libversion(void){ return sqlite3_version; }
49 
50 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
51 ** pointer to a string constant whose value is the same as the
52 ** SQLITE_SOURCE_ID C preprocessor macro.
53 */
54 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
55 
56 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
57 ** returns an integer equal to SQLITE_VERSION_NUMBER.
58 */
59 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
60 
61 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
62 ** zero if and only if SQLite was compiled with mutexing code omitted due to
63 ** the SQLITE_THREADSAFE compile-time option being set to 0.
64 */
65 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
66 
67 /*
68 ** When compiling the test fixture or with debugging enabled (on Win32),
69 ** this variable being set to non-zero will cause OSTRACE macros to emit
70 ** extra diagnostic information.
71 */
72 #ifdef SQLITE_HAVE_OS_TRACE
73 # ifndef SQLITE_DEBUG_OS_TRACE
74 #   define SQLITE_DEBUG_OS_TRACE 0
75 # endif
76   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
77 #endif
78 
79 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
80 /*
81 ** If the following function pointer is not NULL and if
82 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
83 ** I/O active are written using this function.  These messages
84 ** are intended for debugging activity only.
85 */
86 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
87 #endif
88 
89 /*
90 ** If the following global variable points to a string which is the
91 ** name of a directory, then that directory will be used to store
92 ** temporary files.
93 **
94 ** See also the "PRAGMA temp_store_directory" SQL command.
95 */
96 char *sqlite3_temp_directory = 0;
97 
98 /*
99 ** If the following global variable points to a string which is the
100 ** name of a directory, then that directory will be used to store
101 ** all database files specified with a relative pathname.
102 **
103 ** See also the "PRAGMA data_store_directory" SQL command.
104 */
105 char *sqlite3_data_directory = 0;
106 
107 /*
108 ** Initialize SQLite.
109 **
110 ** This routine must be called to initialize the memory allocation,
111 ** VFS, and mutex subsystems prior to doing any serious work with
112 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
113 ** this routine will be called automatically by key routines such as
114 ** sqlite3_open().
115 **
116 ** This routine is a no-op except on its very first call for the process,
117 ** or for the first call after a call to sqlite3_shutdown.
118 **
119 ** The first thread to call this routine runs the initialization to
120 ** completion.  If subsequent threads call this routine before the first
121 ** thread has finished the initialization process, then the subsequent
122 ** threads must block until the first thread finishes with the initialization.
123 **
124 ** The first thread might call this routine recursively.  Recursive
125 ** calls to this routine should not block, of course.  Otherwise the
126 ** initialization process would never complete.
127 **
128 ** Let X be the first thread to enter this routine.  Let Y be some other
129 ** thread.  Then while the initial invocation of this routine by X is
130 ** incomplete, it is required that:
131 **
132 **    *  Calls to this routine from Y must block until the outer-most
133 **       call by X completes.
134 **
135 **    *  Recursive calls to this routine from thread X return immediately
136 **       without blocking.
137 */
138 int sqlite3_initialize(void){
139   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
140   int rc;                                      /* Result code */
141 #ifdef SQLITE_EXTRA_INIT
142   int bRunExtraInit = 0;                       /* Extra initialization needed */
143 #endif
144 
145 #ifdef SQLITE_OMIT_WSD
146   rc = sqlite3_wsd_init(4096, 24);
147   if( rc!=SQLITE_OK ){
148     return rc;
149   }
150 #endif
151 
152   /* If the following assert() fails on some obscure processor/compiler
153   ** combination, the work-around is to set the correct pointer
154   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
155   assert( SQLITE_PTRSIZE==sizeof(char*) );
156 
157   /* If SQLite is already completely initialized, then this call
158   ** to sqlite3_initialize() should be a no-op.  But the initialization
159   ** must be complete.  So isInit must not be set until the very end
160   ** of this routine.
161   */
162   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
163 
164   /* Make sure the mutex subsystem is initialized.  If unable to
165   ** initialize the mutex subsystem, return early with the error.
166   ** If the system is so sick that we are unable to allocate a mutex,
167   ** there is not much SQLite is going to be able to do.
168   **
169   ** The mutex subsystem must take care of serializing its own
170   ** initialization.
171   */
172   rc = sqlite3MutexInit();
173   if( rc ) return rc;
174 
175   /* Initialize the malloc() system and the recursive pInitMutex mutex.
176   ** This operation is protected by the STATIC_MASTER mutex.  Note that
177   ** MutexAlloc() is called for a static mutex prior to initializing the
178   ** malloc subsystem - this implies that the allocation of a static
179   ** mutex must not require support from the malloc subsystem.
180   */
181   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
182   sqlite3_mutex_enter(pMaster);
183   sqlite3GlobalConfig.isMutexInit = 1;
184   if( !sqlite3GlobalConfig.isMallocInit ){
185     rc = sqlite3MallocInit();
186   }
187   if( rc==SQLITE_OK ){
188     sqlite3GlobalConfig.isMallocInit = 1;
189     if( !sqlite3GlobalConfig.pInitMutex ){
190       sqlite3GlobalConfig.pInitMutex =
191            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
192       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
193         rc = SQLITE_NOMEM_BKPT;
194       }
195     }
196   }
197   if( rc==SQLITE_OK ){
198     sqlite3GlobalConfig.nRefInitMutex++;
199   }
200   sqlite3_mutex_leave(pMaster);
201 
202   /* If rc is not SQLITE_OK at this point, then either the malloc
203   ** subsystem could not be initialized or the system failed to allocate
204   ** the pInitMutex mutex. Return an error in either case.  */
205   if( rc!=SQLITE_OK ){
206     return rc;
207   }
208 
209   /* Do the rest of the initialization under the recursive mutex so
210   ** that we will be able to handle recursive calls into
211   ** sqlite3_initialize().  The recursive calls normally come through
212   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
213   ** recursive calls might also be possible.
214   **
215   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
216   ** to the xInit method, so the xInit method need not be threadsafe.
217   **
218   ** The following mutex is what serializes access to the appdef pcache xInit
219   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
220   ** call to sqlite3PcacheInitialize().
221   */
222   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
223   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
224     sqlite3GlobalConfig.inProgress = 1;
225 #ifdef SQLITE_ENABLE_SQLLOG
226     {
227       extern void sqlite3_init_sqllog(void);
228       sqlite3_init_sqllog();
229     }
230 #endif
231     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
232     sqlite3RegisterBuiltinFunctions();
233     if( sqlite3GlobalConfig.isPCacheInit==0 ){
234       rc = sqlite3PcacheInitialize();
235     }
236     if( rc==SQLITE_OK ){
237       sqlite3GlobalConfig.isPCacheInit = 1;
238       rc = sqlite3OsInit();
239     }
240     if( rc==SQLITE_OK ){
241       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
242           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
243       sqlite3GlobalConfig.isInit = 1;
244 #ifdef SQLITE_EXTRA_INIT
245       bRunExtraInit = 1;
246 #endif
247     }
248     sqlite3GlobalConfig.inProgress = 0;
249   }
250   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
251 
252   /* Go back under the static mutex and clean up the recursive
253   ** mutex to prevent a resource leak.
254   */
255   sqlite3_mutex_enter(pMaster);
256   sqlite3GlobalConfig.nRefInitMutex--;
257   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
258     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
259     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
260     sqlite3GlobalConfig.pInitMutex = 0;
261   }
262   sqlite3_mutex_leave(pMaster);
263 
264   /* The following is just a sanity check to make sure SQLite has
265   ** been compiled correctly.  It is important to run this code, but
266   ** we don't want to run it too often and soak up CPU cycles for no
267   ** reason.  So we run it once during initialization.
268   */
269 #ifndef NDEBUG
270 #ifndef SQLITE_OMIT_FLOATING_POINT
271   /* This section of code's only "output" is via assert() statements. */
272   if ( rc==SQLITE_OK ){
273     u64 x = (((u64)1)<<63)-1;
274     double y;
275     assert(sizeof(x)==8);
276     assert(sizeof(x)==sizeof(y));
277     memcpy(&y, &x, 8);
278     assert( sqlite3IsNaN(y) );
279   }
280 #endif
281 #endif
282 
283   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
284   ** compile-time option.
285   */
286 #ifdef SQLITE_EXTRA_INIT
287   if( bRunExtraInit ){
288     int SQLITE_EXTRA_INIT(const char*);
289     rc = SQLITE_EXTRA_INIT(0);
290   }
291 #endif
292 
293   return rc;
294 }
295 
296 /*
297 ** Undo the effects of sqlite3_initialize().  Must not be called while
298 ** there are outstanding database connections or memory allocations or
299 ** while any part of SQLite is otherwise in use in any thread.  This
300 ** routine is not threadsafe.  But it is safe to invoke this routine
301 ** on when SQLite is already shut down.  If SQLite is already shut down
302 ** when this routine is invoked, then this routine is a harmless no-op.
303 */
304 int sqlite3_shutdown(void){
305 #ifdef SQLITE_OMIT_WSD
306   int rc = sqlite3_wsd_init(4096, 24);
307   if( rc!=SQLITE_OK ){
308     return rc;
309   }
310 #endif
311 
312   if( sqlite3GlobalConfig.isInit ){
313 #ifdef SQLITE_EXTRA_SHUTDOWN
314     void SQLITE_EXTRA_SHUTDOWN(void);
315     SQLITE_EXTRA_SHUTDOWN();
316 #endif
317     sqlite3_os_end();
318     sqlite3_reset_auto_extension();
319     sqlite3GlobalConfig.isInit = 0;
320   }
321   if( sqlite3GlobalConfig.isPCacheInit ){
322     sqlite3PcacheShutdown();
323     sqlite3GlobalConfig.isPCacheInit = 0;
324   }
325   if( sqlite3GlobalConfig.isMallocInit ){
326     sqlite3MallocEnd();
327     sqlite3GlobalConfig.isMallocInit = 0;
328 
329 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
330     /* The heap subsystem has now been shutdown and these values are supposed
331     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
332     ** which would rely on that heap subsystem; therefore, make sure these
333     ** values cannot refer to heap memory that was just invalidated when the
334     ** heap subsystem was shutdown.  This is only done if the current call to
335     ** this function resulted in the heap subsystem actually being shutdown.
336     */
337     sqlite3_data_directory = 0;
338     sqlite3_temp_directory = 0;
339 #endif
340   }
341   if( sqlite3GlobalConfig.isMutexInit ){
342     sqlite3MutexEnd();
343     sqlite3GlobalConfig.isMutexInit = 0;
344   }
345 
346   return SQLITE_OK;
347 }
348 
349 /*
350 ** This API allows applications to modify the global configuration of
351 ** the SQLite library at run-time.
352 **
353 ** This routine should only be called when there are no outstanding
354 ** database connections or memory allocations.  This routine is not
355 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
356 ** behavior.
357 */
358 int sqlite3_config(int op, ...){
359   va_list ap;
360   int rc = SQLITE_OK;
361 
362   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
363   ** the SQLite library is in use. */
364   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
365 
366   va_start(ap, op);
367   switch( op ){
368 
369     /* Mutex configuration options are only available in a threadsafe
370     ** compile.
371     */
372 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
373     case SQLITE_CONFIG_SINGLETHREAD: {
374       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
375       ** Single-thread. */
376       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
377       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
378       break;
379     }
380 #endif
381 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
382     case SQLITE_CONFIG_MULTITHREAD: {
383       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
384       ** Multi-thread. */
385       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
386       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
387       break;
388     }
389 #endif
390 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
391     case SQLITE_CONFIG_SERIALIZED: {
392       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
393       ** Serialized. */
394       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
395       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
396       break;
397     }
398 #endif
399 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
400     case SQLITE_CONFIG_MUTEX: {
401       /* Specify an alternative mutex implementation */
402       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
403       break;
404     }
405 #endif
406 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
407     case SQLITE_CONFIG_GETMUTEX: {
408       /* Retrieve the current mutex implementation */
409       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
410       break;
411     }
412 #endif
413 
414     case SQLITE_CONFIG_MALLOC: {
415       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
416       ** single argument which is a pointer to an instance of the
417       ** sqlite3_mem_methods structure. The argument specifies alternative
418       ** low-level memory allocation routines to be used in place of the memory
419       ** allocation routines built into SQLite. */
420       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
421       break;
422     }
423     case SQLITE_CONFIG_GETMALLOC: {
424       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
425       ** single argument which is a pointer to an instance of the
426       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
427       ** filled with the currently defined memory allocation routines. */
428       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
429       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
430       break;
431     }
432     case SQLITE_CONFIG_MEMSTATUS: {
433       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
434       ** single argument of type int, interpreted as a boolean, which enables
435       ** or disables the collection of memory allocation statistics. */
436       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
437       break;
438     }
439     case SQLITE_CONFIG_SCRATCH: {
440       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
441       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
442       ** which the scratch allocations will be drawn, the size of each scratch
443       ** allocation (sz), and the maximum number of scratch allocations (N). */
444       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
445       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
446       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
447       break;
448     }
449     case SQLITE_CONFIG_PAGECACHE: {
450       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
451       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
452       ** the size of each page cache line (sz), and the number of cache lines
453       ** (N). */
454       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
455       sqlite3GlobalConfig.szPage = va_arg(ap, int);
456       sqlite3GlobalConfig.nPage = va_arg(ap, int);
457       break;
458     }
459     case SQLITE_CONFIG_PCACHE_HDRSZ: {
460       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
461       ** a single parameter which is a pointer to an integer and writes into
462       ** that integer the number of extra bytes per page required for each page
463       ** in SQLITE_CONFIG_PAGECACHE. */
464       *va_arg(ap, int*) =
465           sqlite3HeaderSizeBtree() +
466           sqlite3HeaderSizePcache() +
467           sqlite3HeaderSizePcache1();
468       break;
469     }
470 
471     case SQLITE_CONFIG_PCACHE: {
472       /* no-op */
473       break;
474     }
475     case SQLITE_CONFIG_GETPCACHE: {
476       /* now an error */
477       rc = SQLITE_ERROR;
478       break;
479     }
480 
481     case SQLITE_CONFIG_PCACHE2: {
482       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
483       ** single argument which is a pointer to an sqlite3_pcache_methods2
484       ** object. This object specifies the interface to a custom page cache
485       ** implementation. */
486       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
487       break;
488     }
489     case SQLITE_CONFIG_GETPCACHE2: {
490       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
491       ** single argument which is a pointer to an sqlite3_pcache_methods2
492       ** object. SQLite copies of the current page cache implementation into
493       ** that object. */
494       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
495         sqlite3PCacheSetDefault();
496       }
497       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
498       break;
499     }
500 
501 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
502 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
503 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
504 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
505     case SQLITE_CONFIG_HEAP: {
506       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
507       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
508       ** number of bytes in the memory buffer, and the minimum allocation size.
509       */
510       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
511       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
512       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
513 
514       if( sqlite3GlobalConfig.mnReq<1 ){
515         sqlite3GlobalConfig.mnReq = 1;
516       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
517         /* cap min request size at 2^12 */
518         sqlite3GlobalConfig.mnReq = (1<<12);
519       }
520 
521       if( sqlite3GlobalConfig.pHeap==0 ){
522         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
523         ** is NULL, then SQLite reverts to using its default memory allocator
524         ** (the system malloc() implementation), undoing any prior invocation of
525         ** SQLITE_CONFIG_MALLOC.
526         **
527         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
528         ** revert to its default implementation when sqlite3_initialize() is run
529         */
530         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
531       }else{
532         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
533         ** alternative memory allocator is engaged to handle all of SQLites
534         ** memory allocation needs. */
535 #ifdef SQLITE_ENABLE_MEMSYS3
536         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
537 #endif
538 #ifdef SQLITE_ENABLE_MEMSYS5
539         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
540 #endif
541       }
542       break;
543     }
544 #endif
545 
546     case SQLITE_CONFIG_LOOKASIDE: {
547       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
548       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
549       break;
550     }
551 
552     /* Record a pointer to the logger function and its first argument.
553     ** The default is NULL.  Logging is disabled if the function pointer is
554     ** NULL.
555     */
556     case SQLITE_CONFIG_LOG: {
557       /* MSVC is picky about pulling func ptrs from va lists.
558       ** http://support.microsoft.com/kb/47961
559       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
560       */
561       typedef void(*LOGFUNC_t)(void*,int,const char*);
562       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
563       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
564       break;
565     }
566 
567     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
568     ** can be changed at start-time using the
569     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
570     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
571     */
572     case SQLITE_CONFIG_URI: {
573       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
574       ** argument of type int. If non-zero, then URI handling is globally
575       ** enabled. If the parameter is zero, then URI handling is globally
576       ** disabled. */
577       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
578       break;
579     }
580 
581     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
582       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
583       ** option takes a single integer argument which is interpreted as a
584       ** boolean in order to enable or disable the use of covering indices for
585       ** full table scans in the query optimizer. */
586       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
587       break;
588     }
589 
590 #ifdef SQLITE_ENABLE_SQLLOG
591     case SQLITE_CONFIG_SQLLOG: {
592       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
593       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
594       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
595       break;
596     }
597 #endif
598 
599     case SQLITE_CONFIG_MMAP_SIZE: {
600       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
601       ** integer (sqlite3_int64) values that are the default mmap size limit
602       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
603       ** mmap size limit. */
604       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
605       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
606       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
607       ** negative, then that argument is changed to its compile-time default.
608       **
609       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
610       ** silently truncated if necessary so that it does not exceed the
611       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
612       ** compile-time option.
613       */
614       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
615         mxMmap = SQLITE_MAX_MMAP_SIZE;
616       }
617       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
618       if( szMmap>mxMmap) szMmap = mxMmap;
619       sqlite3GlobalConfig.mxMmap = mxMmap;
620       sqlite3GlobalConfig.szMmap = szMmap;
621       break;
622     }
623 
624 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
625     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
626       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
627       ** unsigned integer value that specifies the maximum size of the created
628       ** heap. */
629       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
630       break;
631     }
632 #endif
633 
634     case SQLITE_CONFIG_PMASZ: {
635       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
636       break;
637     }
638 
639     case SQLITE_CONFIG_STMTJRNL_SPILL: {
640       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
641       break;
642     }
643 
644     default: {
645       rc = SQLITE_ERROR;
646       break;
647     }
648   }
649   va_end(ap);
650   return rc;
651 }
652 
653 /*
654 ** Set up the lookaside buffers for a database connection.
655 ** Return SQLITE_OK on success.
656 ** If lookaside is already active, return SQLITE_BUSY.
657 **
658 ** The sz parameter is the number of bytes in each lookaside slot.
659 ** The cnt parameter is the number of slots.  If pStart is NULL the
660 ** space for the lookaside memory is obtained from sqlite3_malloc().
661 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
662 ** the lookaside memory.
663 */
664 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
665 #ifndef SQLITE_OMIT_LOOKASIDE
666   void *pStart;
667   if( db->lookaside.nOut ){
668     return SQLITE_BUSY;
669   }
670   /* Free any existing lookaside buffer for this handle before
671   ** allocating a new one so we don't have to have space for
672   ** both at the same time.
673   */
674   if( db->lookaside.bMalloced ){
675     sqlite3_free(db->lookaside.pStart);
676   }
677   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
678   ** than a pointer to be useful.
679   */
680   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
681   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
682   if( cnt<0 ) cnt = 0;
683   if( sz==0 || cnt==0 ){
684     sz = 0;
685     pStart = 0;
686   }else if( pBuf==0 ){
687     sqlite3BeginBenignMalloc();
688     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
689     sqlite3EndBenignMalloc();
690     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
691   }else{
692     pStart = pBuf;
693   }
694   db->lookaside.pStart = pStart;
695   db->lookaside.pFree = 0;
696   db->lookaside.sz = (u16)sz;
697   if( pStart ){
698     int i;
699     LookasideSlot *p;
700     assert( sz > (int)sizeof(LookasideSlot*) );
701     p = (LookasideSlot*)pStart;
702     for(i=cnt-1; i>=0; i--){
703       p->pNext = db->lookaside.pFree;
704       db->lookaside.pFree = p;
705       p = (LookasideSlot*)&((u8*)p)[sz];
706     }
707     db->lookaside.pEnd = p;
708     db->lookaside.bDisable = 0;
709     db->lookaside.bMalloced = pBuf==0 ?1:0;
710   }else{
711     db->lookaside.pStart = db;
712     db->lookaside.pEnd = db;
713     db->lookaside.bDisable = 1;
714     db->lookaside.bMalloced = 0;
715   }
716 #endif /* SQLITE_OMIT_LOOKASIDE */
717   return SQLITE_OK;
718 }
719 
720 /*
721 ** Return the mutex associated with a database connection.
722 */
723 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
724 #ifdef SQLITE_ENABLE_API_ARMOR
725   if( !sqlite3SafetyCheckOk(db) ){
726     (void)SQLITE_MISUSE_BKPT;
727     return 0;
728   }
729 #endif
730   return db->mutex;
731 }
732 
733 /*
734 ** Free up as much memory as we can from the given database
735 ** connection.
736 */
737 int sqlite3_db_release_memory(sqlite3 *db){
738   int i;
739 
740 #ifdef SQLITE_ENABLE_API_ARMOR
741   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
742 #endif
743   sqlite3_mutex_enter(db->mutex);
744   sqlite3BtreeEnterAll(db);
745   for(i=0; i<db->nDb; i++){
746     Btree *pBt = db->aDb[i].pBt;
747     if( pBt ){
748       Pager *pPager = sqlite3BtreePager(pBt);
749       sqlite3PagerShrink(pPager);
750     }
751   }
752   sqlite3BtreeLeaveAll(db);
753   sqlite3_mutex_leave(db->mutex);
754   return SQLITE_OK;
755 }
756 
757 /*
758 ** Flush any dirty pages in the pager-cache for any attached database
759 ** to disk.
760 */
761 int sqlite3_db_cacheflush(sqlite3 *db){
762   int i;
763   int rc = SQLITE_OK;
764   int bSeenBusy = 0;
765 
766 #ifdef SQLITE_ENABLE_API_ARMOR
767   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
768 #endif
769   sqlite3_mutex_enter(db->mutex);
770   sqlite3BtreeEnterAll(db);
771   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
772     Btree *pBt = db->aDb[i].pBt;
773     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
774       Pager *pPager = sqlite3BtreePager(pBt);
775       rc = sqlite3PagerFlush(pPager);
776       if( rc==SQLITE_BUSY ){
777         bSeenBusy = 1;
778         rc = SQLITE_OK;
779       }
780     }
781   }
782   sqlite3BtreeLeaveAll(db);
783   sqlite3_mutex_leave(db->mutex);
784   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
785 }
786 
787 /*
788 ** Configuration settings for an individual database connection
789 */
790 int sqlite3_db_config(sqlite3 *db, int op, ...){
791   va_list ap;
792   int rc;
793   va_start(ap, op);
794   switch( op ){
795     case SQLITE_DBCONFIG_MAINDBNAME: {
796       db->aDb[0].zDbSName = va_arg(ap,char*);
797       rc = SQLITE_OK;
798       break;
799     }
800     case SQLITE_DBCONFIG_LOOKASIDE: {
801       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
802       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
803       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
804       rc = setupLookaside(db, pBuf, sz, cnt);
805       break;
806     }
807     default: {
808       static const struct {
809         int op;      /* The opcode */
810         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
811       } aFlagOp[] = {
812         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
813         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
814         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
815         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
816         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
817         { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
818       };
819       unsigned int i;
820       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
821       for(i=0; i<ArraySize(aFlagOp); i++){
822         if( aFlagOp[i].op==op ){
823           int onoff = va_arg(ap, int);
824           int *pRes = va_arg(ap, int*);
825           int oldFlags = db->flags;
826           if( onoff>0 ){
827             db->flags |= aFlagOp[i].mask;
828           }else if( onoff==0 ){
829             db->flags &= ~aFlagOp[i].mask;
830           }
831           if( oldFlags!=db->flags ){
832             sqlite3ExpirePreparedStatements(db);
833           }
834           if( pRes ){
835             *pRes = (db->flags & aFlagOp[i].mask)!=0;
836           }
837           rc = SQLITE_OK;
838           break;
839         }
840       }
841       break;
842     }
843   }
844   va_end(ap);
845   return rc;
846 }
847 
848 
849 /*
850 ** Return true if the buffer z[0..n-1] contains all spaces.
851 */
852 static int allSpaces(const char *z, int n){
853   while( n>0 && z[n-1]==' ' ){ n--; }
854   return n==0;
855 }
856 
857 /*
858 ** This is the default collating function named "BINARY" which is always
859 ** available.
860 **
861 ** If the padFlag argument is not NULL then space padding at the end
862 ** of strings is ignored.  This implements the RTRIM collation.
863 */
864 static int binCollFunc(
865   void *padFlag,
866   int nKey1, const void *pKey1,
867   int nKey2, const void *pKey2
868 ){
869   int rc, n;
870   n = nKey1<nKey2 ? nKey1 : nKey2;
871   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
872   ** strings byte by byte using the memcmp() function from the standard C
873   ** library. */
874   assert( pKey1 && pKey2 );
875   rc = memcmp(pKey1, pKey2, n);
876   if( rc==0 ){
877     if( padFlag
878      && allSpaces(((char*)pKey1)+n, nKey1-n)
879      && allSpaces(((char*)pKey2)+n, nKey2-n)
880     ){
881       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
882       ** spaces at the end of either string do not change the result. In other
883       ** words, strings will compare equal to one another as long as they
884       ** differ only in the number of spaces at the end.
885       */
886     }else{
887       rc = nKey1 - nKey2;
888     }
889   }
890   return rc;
891 }
892 
893 /*
894 ** Another built-in collating sequence: NOCASE.
895 **
896 ** This collating sequence is intended to be used for "case independent
897 ** comparison". SQLite's knowledge of upper and lower case equivalents
898 ** extends only to the 26 characters used in the English language.
899 **
900 ** At the moment there is only a UTF-8 implementation.
901 */
902 static int nocaseCollatingFunc(
903   void *NotUsed,
904   int nKey1, const void *pKey1,
905   int nKey2, const void *pKey2
906 ){
907   int r = sqlite3StrNICmp(
908       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
909   UNUSED_PARAMETER(NotUsed);
910   if( 0==r ){
911     r = nKey1-nKey2;
912   }
913   return r;
914 }
915 
916 /*
917 ** Return the ROWID of the most recent insert
918 */
919 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
920 #ifdef SQLITE_ENABLE_API_ARMOR
921   if( !sqlite3SafetyCheckOk(db) ){
922     (void)SQLITE_MISUSE_BKPT;
923     return 0;
924   }
925 #endif
926   return db->lastRowid;
927 }
928 
929 /*
930 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
931 */
932 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
933 #ifdef SQLITE_ENABLE_API_ARMOR
934   if( !sqlite3SafetyCheckOk(db) ){
935     (void)SQLITE_MISUSE_BKPT;
936     return;
937   }
938 #endif
939   sqlite3_mutex_enter(db->mutex);
940   db->lastRowid = iRowid;
941   sqlite3_mutex_leave(db->mutex);
942 }
943 
944 /*
945 ** Return the number of changes in the most recent call to sqlite3_exec().
946 */
947 int sqlite3_changes(sqlite3 *db){
948 #ifdef SQLITE_ENABLE_API_ARMOR
949   if( !sqlite3SafetyCheckOk(db) ){
950     (void)SQLITE_MISUSE_BKPT;
951     return 0;
952   }
953 #endif
954   return db->nChange;
955 }
956 
957 /*
958 ** Return the number of changes since the database handle was opened.
959 */
960 int sqlite3_total_changes(sqlite3 *db){
961 #ifdef SQLITE_ENABLE_API_ARMOR
962   if( !sqlite3SafetyCheckOk(db) ){
963     (void)SQLITE_MISUSE_BKPT;
964     return 0;
965   }
966 #endif
967   return db->nTotalChange;
968 }
969 
970 /*
971 ** Close all open savepoints. This function only manipulates fields of the
972 ** database handle object, it does not close any savepoints that may be open
973 ** at the b-tree/pager level.
974 */
975 void sqlite3CloseSavepoints(sqlite3 *db){
976   while( db->pSavepoint ){
977     Savepoint *pTmp = db->pSavepoint;
978     db->pSavepoint = pTmp->pNext;
979     sqlite3DbFree(db, pTmp);
980   }
981   db->nSavepoint = 0;
982   db->nStatement = 0;
983   db->isTransactionSavepoint = 0;
984 }
985 
986 /*
987 ** Invoke the destructor function associated with FuncDef p, if any. Except,
988 ** if this is not the last copy of the function, do not invoke it. Multiple
989 ** copies of a single function are created when create_function() is called
990 ** with SQLITE_ANY as the encoding.
991 */
992 static void functionDestroy(sqlite3 *db, FuncDef *p){
993   FuncDestructor *pDestructor = p->u.pDestructor;
994   if( pDestructor ){
995     pDestructor->nRef--;
996     if( pDestructor->nRef==0 ){
997       pDestructor->xDestroy(pDestructor->pUserData);
998       sqlite3DbFree(db, pDestructor);
999     }
1000   }
1001 }
1002 
1003 /*
1004 ** Disconnect all sqlite3_vtab objects that belong to database connection
1005 ** db. This is called when db is being closed.
1006 */
1007 static void disconnectAllVtab(sqlite3 *db){
1008 #ifndef SQLITE_OMIT_VIRTUALTABLE
1009   int i;
1010   HashElem *p;
1011   sqlite3BtreeEnterAll(db);
1012   for(i=0; i<db->nDb; i++){
1013     Schema *pSchema = db->aDb[i].pSchema;
1014     if( db->aDb[i].pSchema ){
1015       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1016         Table *pTab = (Table *)sqliteHashData(p);
1017         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1018       }
1019     }
1020   }
1021   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1022     Module *pMod = (Module *)sqliteHashData(p);
1023     if( pMod->pEpoTab ){
1024       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1025     }
1026   }
1027   sqlite3VtabUnlockList(db);
1028   sqlite3BtreeLeaveAll(db);
1029 #else
1030   UNUSED_PARAMETER(db);
1031 #endif
1032 }
1033 
1034 /*
1035 ** Return TRUE if database connection db has unfinalized prepared
1036 ** statements or unfinished sqlite3_backup objects.
1037 */
1038 static int connectionIsBusy(sqlite3 *db){
1039   int j;
1040   assert( sqlite3_mutex_held(db->mutex) );
1041   if( db->pVdbe ) return 1;
1042   for(j=0; j<db->nDb; j++){
1043     Btree *pBt = db->aDb[j].pBt;
1044     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1045   }
1046   return 0;
1047 }
1048 
1049 /*
1050 ** Close an existing SQLite database
1051 */
1052 static int sqlite3Close(sqlite3 *db, int forceZombie){
1053   if( !db ){
1054     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1055     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1056     return SQLITE_OK;
1057   }
1058   if( !sqlite3SafetyCheckSickOrOk(db) ){
1059     return SQLITE_MISUSE_BKPT;
1060   }
1061   sqlite3_mutex_enter(db->mutex);
1062   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1063     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1064   }
1065 
1066   /* Force xDisconnect calls on all virtual tables */
1067   disconnectAllVtab(db);
1068 
1069   /* If a transaction is open, the disconnectAllVtab() call above
1070   ** will not have called the xDisconnect() method on any virtual
1071   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1072   ** call will do so. We need to do this before the check for active
1073   ** SQL statements below, as the v-table implementation may be storing
1074   ** some prepared statements internally.
1075   */
1076   sqlite3VtabRollback(db);
1077 
1078   /* Legacy behavior (sqlite3_close() behavior) is to return
1079   ** SQLITE_BUSY if the connection can not be closed immediately.
1080   */
1081   if( !forceZombie && connectionIsBusy(db) ){
1082     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1083        "statements or unfinished backups");
1084     sqlite3_mutex_leave(db->mutex);
1085     return SQLITE_BUSY;
1086   }
1087 
1088 #ifdef SQLITE_ENABLE_SQLLOG
1089   if( sqlite3GlobalConfig.xSqllog ){
1090     /* Closing the handle. Fourth parameter is passed the value 2. */
1091     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1092   }
1093 #endif
1094 
1095   /* Convert the connection into a zombie and then close it.
1096   */
1097   db->magic = SQLITE_MAGIC_ZOMBIE;
1098   sqlite3LeaveMutexAndCloseZombie(db);
1099   return SQLITE_OK;
1100 }
1101 
1102 /*
1103 ** Two variations on the public interface for closing a database
1104 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1105 ** leaves the connection option if there are unfinalized prepared
1106 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1107 ** version forces the connection to become a zombie if there are
1108 ** unclosed resources, and arranges for deallocation when the last
1109 ** prepare statement or sqlite3_backup closes.
1110 */
1111 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1112 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1113 
1114 
1115 /*
1116 ** Close the mutex on database connection db.
1117 **
1118 ** Furthermore, if database connection db is a zombie (meaning that there
1119 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1120 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1121 ** finished, then free all resources.
1122 */
1123 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1124   HashElem *i;                    /* Hash table iterator */
1125   int j;
1126 
1127   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1128   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1129   ** then just leave the mutex and return.
1130   */
1131   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1132     sqlite3_mutex_leave(db->mutex);
1133     return;
1134   }
1135 
1136   /* If we reach this point, it means that the database connection has
1137   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1138   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1139   ** go ahead and free all resources.
1140   */
1141 
1142   /* If a transaction is open, roll it back. This also ensures that if
1143   ** any database schemas have been modified by an uncommitted transaction
1144   ** they are reset. And that the required b-tree mutex is held to make
1145   ** the pager rollback and schema reset an atomic operation. */
1146   sqlite3RollbackAll(db, SQLITE_OK);
1147 
1148   /* Free any outstanding Savepoint structures. */
1149   sqlite3CloseSavepoints(db);
1150 
1151   /* Close all database connections */
1152   for(j=0; j<db->nDb; j++){
1153     struct Db *pDb = &db->aDb[j];
1154     if( pDb->pBt ){
1155       sqlite3BtreeClose(pDb->pBt);
1156       pDb->pBt = 0;
1157       if( j!=1 ){
1158         pDb->pSchema = 0;
1159       }
1160     }
1161   }
1162   /* Clear the TEMP schema separately and last */
1163   if( db->aDb[1].pSchema ){
1164     sqlite3SchemaClear(db->aDb[1].pSchema);
1165   }
1166   sqlite3VtabUnlockList(db);
1167 
1168   /* Free up the array of auxiliary databases */
1169   sqlite3CollapseDatabaseArray(db);
1170   assert( db->nDb<=2 );
1171   assert( db->aDb==db->aDbStatic );
1172 
1173   /* Tell the code in notify.c that the connection no longer holds any
1174   ** locks and does not require any further unlock-notify callbacks.
1175   */
1176   sqlite3ConnectionClosed(db);
1177 
1178   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1179     FuncDef *pNext, *p;
1180     p = sqliteHashData(i);
1181     do{
1182       functionDestroy(db, p);
1183       pNext = p->pNext;
1184       sqlite3DbFree(db, p);
1185       p = pNext;
1186     }while( p );
1187   }
1188   sqlite3HashClear(&db->aFunc);
1189   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1190     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1191     /* Invoke any destructors registered for collation sequence user data. */
1192     for(j=0; j<3; j++){
1193       if( pColl[j].xDel ){
1194         pColl[j].xDel(pColl[j].pUser);
1195       }
1196     }
1197     sqlite3DbFree(db, pColl);
1198   }
1199   sqlite3HashClear(&db->aCollSeq);
1200 #ifndef SQLITE_OMIT_VIRTUALTABLE
1201   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1202     Module *pMod = (Module *)sqliteHashData(i);
1203     if( pMod->xDestroy ){
1204       pMod->xDestroy(pMod->pAux);
1205     }
1206     sqlite3VtabEponymousTableClear(db, pMod);
1207     sqlite3DbFree(db, pMod);
1208   }
1209   sqlite3HashClear(&db->aModule);
1210 #endif
1211 
1212   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1213   sqlite3ValueFree(db->pErr);
1214   sqlite3CloseExtensions(db);
1215 #if SQLITE_USER_AUTHENTICATION
1216   sqlite3_free(db->auth.zAuthUser);
1217   sqlite3_free(db->auth.zAuthPW);
1218 #endif
1219 
1220   db->magic = SQLITE_MAGIC_ERROR;
1221 
1222   /* The temp-database schema is allocated differently from the other schema
1223   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1224   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1225   ** the same sqliteMalloc() as the one that allocates the database
1226   ** structure?
1227   */
1228   sqlite3DbFree(db, db->aDb[1].pSchema);
1229   sqlite3_mutex_leave(db->mutex);
1230   db->magic = SQLITE_MAGIC_CLOSED;
1231   sqlite3_mutex_free(db->mutex);
1232   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1233   if( db->lookaside.bMalloced ){
1234     sqlite3_free(db->lookaside.pStart);
1235   }
1236   sqlite3_free(db);
1237 }
1238 
1239 /*
1240 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1241 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1242 ** breaker") and made to return tripCode if there are any further
1243 ** attempts to use that cursor.  Read cursors remain open and valid
1244 ** but are "saved" in case the table pages are moved around.
1245 */
1246 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1247   int i;
1248   int inTrans = 0;
1249   int schemaChange;
1250   assert( sqlite3_mutex_held(db->mutex) );
1251   sqlite3BeginBenignMalloc();
1252 
1253   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1254   ** This is important in case the transaction being rolled back has
1255   ** modified the database schema. If the b-tree mutexes are not taken
1256   ** here, then another shared-cache connection might sneak in between
1257   ** the database rollback and schema reset, which can cause false
1258   ** corruption reports in some cases.  */
1259   sqlite3BtreeEnterAll(db);
1260   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1261 
1262   for(i=0; i<db->nDb; i++){
1263     Btree *p = db->aDb[i].pBt;
1264     if( p ){
1265       if( sqlite3BtreeIsInTrans(p) ){
1266         inTrans = 1;
1267       }
1268       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1269     }
1270   }
1271   sqlite3VtabRollback(db);
1272   sqlite3EndBenignMalloc();
1273 
1274   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1275     sqlite3ExpirePreparedStatements(db);
1276     sqlite3ResetAllSchemasOfConnection(db);
1277   }
1278   sqlite3BtreeLeaveAll(db);
1279 
1280   /* Any deferred constraint violations have now been resolved. */
1281   db->nDeferredCons = 0;
1282   db->nDeferredImmCons = 0;
1283   db->flags &= ~SQLITE_DeferFKs;
1284 
1285   /* If one has been configured, invoke the rollback-hook callback */
1286   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1287     db->xRollbackCallback(db->pRollbackArg);
1288   }
1289 }
1290 
1291 /*
1292 ** Return a static string containing the name corresponding to the error code
1293 ** specified in the argument.
1294 */
1295 #if defined(SQLITE_NEED_ERR_NAME)
1296 const char *sqlite3ErrName(int rc){
1297   const char *zName = 0;
1298   int i, origRc = rc;
1299   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1300     switch( rc ){
1301       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1302       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1303       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1304       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1305       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1306       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1307       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1308       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1309       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1310       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1311       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1312       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1313       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1314       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1315       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1316       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1317       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1318       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1319       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1320       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1321       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1322       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1323       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1324       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1325       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1326       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1327       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1328       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1329       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1330       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1331       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1332       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1333                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1334       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1335       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1336       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1337       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1338       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1339       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1340       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1341       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1342       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1343       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1344       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1345       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1346       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1347       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1348       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1349       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1350       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1351       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1352       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1353       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1354       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1355       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1356       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1357       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1358       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1359       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1360       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1361       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1362       case SQLITE_CONSTRAINT_FOREIGNKEY:
1363                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1364       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1365       case SQLITE_CONSTRAINT_PRIMARYKEY:
1366                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1367       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1368       case SQLITE_CONSTRAINT_COMMITHOOK:
1369                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1370       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1371       case SQLITE_CONSTRAINT_FUNCTION:
1372                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1373       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1374       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1375       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1376       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1377       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1378       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1379       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1380       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1381       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1382       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1383       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1384       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1385                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1386       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1387       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1388       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1389     }
1390   }
1391   if( zName==0 ){
1392     static char zBuf[50];
1393     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1394     zName = zBuf;
1395   }
1396   return zName;
1397 }
1398 #endif
1399 
1400 /*
1401 ** Return a static string that describes the kind of error specified in the
1402 ** argument.
1403 */
1404 const char *sqlite3ErrStr(int rc){
1405   static const char* const aMsg[] = {
1406     /* SQLITE_OK          */ "not an error",
1407     /* SQLITE_ERROR       */ "SQL logic error",
1408     /* SQLITE_INTERNAL    */ 0,
1409     /* SQLITE_PERM        */ "access permission denied",
1410     /* SQLITE_ABORT       */ "callback requested query abort",
1411     /* SQLITE_BUSY        */ "database is locked",
1412     /* SQLITE_LOCKED      */ "database table is locked",
1413     /* SQLITE_NOMEM       */ "out of memory",
1414     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1415     /* SQLITE_INTERRUPT   */ "interrupted",
1416     /* SQLITE_IOERR       */ "disk I/O error",
1417     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1418     /* SQLITE_NOTFOUND    */ "unknown operation",
1419     /* SQLITE_FULL        */ "database or disk is full",
1420     /* SQLITE_CANTOPEN    */ "unable to open database file",
1421     /* SQLITE_PROTOCOL    */ "locking protocol",
1422     /* SQLITE_EMPTY       */ "table contains no data",
1423     /* SQLITE_SCHEMA      */ "database schema has changed",
1424     /* SQLITE_TOOBIG      */ "string or blob too big",
1425     /* SQLITE_CONSTRAINT  */ "constraint failed",
1426     /* SQLITE_MISMATCH    */ "datatype mismatch",
1427     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1428     /* SQLITE_NOLFS       */ "large file support is disabled",
1429     /* SQLITE_AUTH        */ "authorization denied",
1430     /* SQLITE_FORMAT      */ "auxiliary database format error",
1431     /* SQLITE_RANGE       */ "bind or column index out of range",
1432     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1433   };
1434   const char *zErr = "unknown error";
1435   switch( rc ){
1436     case SQLITE_ABORT_ROLLBACK: {
1437       zErr = "abort due to ROLLBACK";
1438       break;
1439     }
1440     default: {
1441       rc &= 0xff;
1442       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1443         zErr = aMsg[rc];
1444       }
1445       break;
1446     }
1447   }
1448   return zErr;
1449 }
1450 
1451 /*
1452 ** This routine implements a busy callback that sleeps and tries
1453 ** again until a timeout value is reached.  The timeout value is
1454 ** an integer number of milliseconds passed in as the first
1455 ** argument.
1456 */
1457 static int sqliteDefaultBusyCallback(
1458  void *ptr,               /* Database connection */
1459  int count                /* Number of times table has been busy */
1460 ){
1461 #if SQLITE_OS_WIN || HAVE_USLEEP
1462   static const u8 delays[] =
1463      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1464   static const u8 totals[] =
1465      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1466 # define NDELAY ArraySize(delays)
1467   sqlite3 *db = (sqlite3 *)ptr;
1468   int timeout = db->busyTimeout;
1469   int delay, prior;
1470 
1471   assert( count>=0 );
1472   if( count < NDELAY ){
1473     delay = delays[count];
1474     prior = totals[count];
1475   }else{
1476     delay = delays[NDELAY-1];
1477     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1478   }
1479   if( prior + delay > timeout ){
1480     delay = timeout - prior;
1481     if( delay<=0 ) return 0;
1482   }
1483   sqlite3OsSleep(db->pVfs, delay*1000);
1484   return 1;
1485 #else
1486   sqlite3 *db = (sqlite3 *)ptr;
1487   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1488   if( (count+1)*1000 > timeout ){
1489     return 0;
1490   }
1491   sqlite3OsSleep(db->pVfs, 1000000);
1492   return 1;
1493 #endif
1494 }
1495 
1496 /*
1497 ** Invoke the given busy handler.
1498 **
1499 ** This routine is called when an operation failed with a lock.
1500 ** If this routine returns non-zero, the lock is retried.  If it
1501 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1502 */
1503 int sqlite3InvokeBusyHandler(BusyHandler *p){
1504   int rc;
1505   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1506   rc = p->xFunc(p->pArg, p->nBusy);
1507   if( rc==0 ){
1508     p->nBusy = -1;
1509   }else{
1510     p->nBusy++;
1511   }
1512   return rc;
1513 }
1514 
1515 /*
1516 ** This routine sets the busy callback for an Sqlite database to the
1517 ** given callback function with the given argument.
1518 */
1519 int sqlite3_busy_handler(
1520   sqlite3 *db,
1521   int (*xBusy)(void*,int),
1522   void *pArg
1523 ){
1524 #ifdef SQLITE_ENABLE_API_ARMOR
1525   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1526 #endif
1527   sqlite3_mutex_enter(db->mutex);
1528   db->busyHandler.xFunc = xBusy;
1529   db->busyHandler.pArg = pArg;
1530   db->busyHandler.nBusy = 0;
1531   db->busyTimeout = 0;
1532   sqlite3_mutex_leave(db->mutex);
1533   return SQLITE_OK;
1534 }
1535 
1536 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1537 /*
1538 ** This routine sets the progress callback for an Sqlite database to the
1539 ** given callback function with the given argument. The progress callback will
1540 ** be invoked every nOps opcodes.
1541 */
1542 void sqlite3_progress_handler(
1543   sqlite3 *db,
1544   int nOps,
1545   int (*xProgress)(void*),
1546   void *pArg
1547 ){
1548 #ifdef SQLITE_ENABLE_API_ARMOR
1549   if( !sqlite3SafetyCheckOk(db) ){
1550     (void)SQLITE_MISUSE_BKPT;
1551     return;
1552   }
1553 #endif
1554   sqlite3_mutex_enter(db->mutex);
1555   if( nOps>0 ){
1556     db->xProgress = xProgress;
1557     db->nProgressOps = (unsigned)nOps;
1558     db->pProgressArg = pArg;
1559   }else{
1560     db->xProgress = 0;
1561     db->nProgressOps = 0;
1562     db->pProgressArg = 0;
1563   }
1564   sqlite3_mutex_leave(db->mutex);
1565 }
1566 #endif
1567 
1568 
1569 /*
1570 ** This routine installs a default busy handler that waits for the
1571 ** specified number of milliseconds before returning 0.
1572 */
1573 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1574 #ifdef SQLITE_ENABLE_API_ARMOR
1575   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1576 #endif
1577   if( ms>0 ){
1578     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1579     db->busyTimeout = ms;
1580   }else{
1581     sqlite3_busy_handler(db, 0, 0);
1582   }
1583   return SQLITE_OK;
1584 }
1585 
1586 /*
1587 ** Cause any pending operation to stop at its earliest opportunity.
1588 */
1589 void sqlite3_interrupt(sqlite3 *db){
1590 #ifdef SQLITE_ENABLE_API_ARMOR
1591   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1592     (void)SQLITE_MISUSE_BKPT;
1593     return;
1594   }
1595 #endif
1596   db->u1.isInterrupted = 1;
1597 }
1598 
1599 
1600 /*
1601 ** This function is exactly the same as sqlite3_create_function(), except
1602 ** that it is designed to be called by internal code. The difference is
1603 ** that if a malloc() fails in sqlite3_create_function(), an error code
1604 ** is returned and the mallocFailed flag cleared.
1605 */
1606 int sqlite3CreateFunc(
1607   sqlite3 *db,
1608   const char *zFunctionName,
1609   int nArg,
1610   int enc,
1611   void *pUserData,
1612   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1613   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1614   void (*xFinal)(sqlite3_context*),
1615   FuncDestructor *pDestructor
1616 ){
1617   FuncDef *p;
1618   int nName;
1619   int extraFlags;
1620 
1621   assert( sqlite3_mutex_held(db->mutex) );
1622   if( zFunctionName==0 ||
1623       (xSFunc && (xFinal || xStep)) ||
1624       (!xSFunc && (xFinal && !xStep)) ||
1625       (!xSFunc && (!xFinal && xStep)) ||
1626       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1627       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1628     return SQLITE_MISUSE_BKPT;
1629   }
1630 
1631   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1632   extraFlags = enc &  SQLITE_DETERMINISTIC;
1633   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1634 
1635 #ifndef SQLITE_OMIT_UTF16
1636   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1637   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1638   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1639   **
1640   ** If SQLITE_ANY is specified, add three versions of the function
1641   ** to the hash table.
1642   */
1643   if( enc==SQLITE_UTF16 ){
1644     enc = SQLITE_UTF16NATIVE;
1645   }else if( enc==SQLITE_ANY ){
1646     int rc;
1647     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1648          pUserData, xSFunc, xStep, xFinal, pDestructor);
1649     if( rc==SQLITE_OK ){
1650       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1651           pUserData, xSFunc, xStep, xFinal, pDestructor);
1652     }
1653     if( rc!=SQLITE_OK ){
1654       return rc;
1655     }
1656     enc = SQLITE_UTF16BE;
1657   }
1658 #else
1659   enc = SQLITE_UTF8;
1660 #endif
1661 
1662   /* Check if an existing function is being overridden or deleted. If so,
1663   ** and there are active VMs, then return SQLITE_BUSY. If a function
1664   ** is being overridden/deleted but there are no active VMs, allow the
1665   ** operation to continue but invalidate all precompiled statements.
1666   */
1667   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1668   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1669     if( db->nVdbeActive ){
1670       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1671         "unable to delete/modify user-function due to active statements");
1672       assert( !db->mallocFailed );
1673       return SQLITE_BUSY;
1674     }else{
1675       sqlite3ExpirePreparedStatements(db);
1676     }
1677   }
1678 
1679   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1680   assert(p || db->mallocFailed);
1681   if( !p ){
1682     return SQLITE_NOMEM_BKPT;
1683   }
1684 
1685   /* If an older version of the function with a configured destructor is
1686   ** being replaced invoke the destructor function here. */
1687   functionDestroy(db, p);
1688 
1689   if( pDestructor ){
1690     pDestructor->nRef++;
1691   }
1692   p->u.pDestructor = pDestructor;
1693   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1694   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1695   p->xSFunc = xSFunc ? xSFunc : xStep;
1696   p->xFinalize = xFinal;
1697   p->pUserData = pUserData;
1698   p->nArg = (u16)nArg;
1699   return SQLITE_OK;
1700 }
1701 
1702 /*
1703 ** Create new user functions.
1704 */
1705 int sqlite3_create_function(
1706   sqlite3 *db,
1707   const char *zFunc,
1708   int nArg,
1709   int enc,
1710   void *p,
1711   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1712   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1713   void (*xFinal)(sqlite3_context*)
1714 ){
1715   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1716                                     xFinal, 0);
1717 }
1718 
1719 int sqlite3_create_function_v2(
1720   sqlite3 *db,
1721   const char *zFunc,
1722   int nArg,
1723   int enc,
1724   void *p,
1725   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1726   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1727   void (*xFinal)(sqlite3_context*),
1728   void (*xDestroy)(void *)
1729 ){
1730   int rc = SQLITE_ERROR;
1731   FuncDestructor *pArg = 0;
1732 
1733 #ifdef SQLITE_ENABLE_API_ARMOR
1734   if( !sqlite3SafetyCheckOk(db) ){
1735     return SQLITE_MISUSE_BKPT;
1736   }
1737 #endif
1738   sqlite3_mutex_enter(db->mutex);
1739   if( xDestroy ){
1740     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1741     if( !pArg ){
1742       xDestroy(p);
1743       goto out;
1744     }
1745     pArg->xDestroy = xDestroy;
1746     pArg->pUserData = p;
1747   }
1748   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1749   if( pArg && pArg->nRef==0 ){
1750     assert( rc!=SQLITE_OK );
1751     xDestroy(p);
1752     sqlite3DbFree(db, pArg);
1753   }
1754 
1755  out:
1756   rc = sqlite3ApiExit(db, rc);
1757   sqlite3_mutex_leave(db->mutex);
1758   return rc;
1759 }
1760 
1761 #ifndef SQLITE_OMIT_UTF16
1762 int sqlite3_create_function16(
1763   sqlite3 *db,
1764   const void *zFunctionName,
1765   int nArg,
1766   int eTextRep,
1767   void *p,
1768   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1769   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1770   void (*xFinal)(sqlite3_context*)
1771 ){
1772   int rc;
1773   char *zFunc8;
1774 
1775 #ifdef SQLITE_ENABLE_API_ARMOR
1776   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1777 #endif
1778   sqlite3_mutex_enter(db->mutex);
1779   assert( !db->mallocFailed );
1780   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1781   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1782   sqlite3DbFree(db, zFunc8);
1783   rc = sqlite3ApiExit(db, rc);
1784   sqlite3_mutex_leave(db->mutex);
1785   return rc;
1786 }
1787 #endif
1788 
1789 
1790 /*
1791 ** Declare that a function has been overloaded by a virtual table.
1792 **
1793 ** If the function already exists as a regular global function, then
1794 ** this routine is a no-op.  If the function does not exist, then create
1795 ** a new one that always throws a run-time error.
1796 **
1797 ** When virtual tables intend to provide an overloaded function, they
1798 ** should call this routine to make sure the global function exists.
1799 ** A global function must exist in order for name resolution to work
1800 ** properly.
1801 */
1802 int sqlite3_overload_function(
1803   sqlite3 *db,
1804   const char *zName,
1805   int nArg
1806 ){
1807   int rc = SQLITE_OK;
1808 
1809 #ifdef SQLITE_ENABLE_API_ARMOR
1810   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1811     return SQLITE_MISUSE_BKPT;
1812   }
1813 #endif
1814   sqlite3_mutex_enter(db->mutex);
1815   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1816     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1817                            0, sqlite3InvalidFunction, 0, 0, 0);
1818   }
1819   rc = sqlite3ApiExit(db, rc);
1820   sqlite3_mutex_leave(db->mutex);
1821   return rc;
1822 }
1823 
1824 #ifndef SQLITE_OMIT_TRACE
1825 /*
1826 ** Register a trace function.  The pArg from the previously registered trace
1827 ** is returned.
1828 **
1829 ** A NULL trace function means that no tracing is executes.  A non-NULL
1830 ** trace is a pointer to a function that is invoked at the start of each
1831 ** SQL statement.
1832 */
1833 #ifndef SQLITE_OMIT_DEPRECATED
1834 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1835   void *pOld;
1836 
1837 #ifdef SQLITE_ENABLE_API_ARMOR
1838   if( !sqlite3SafetyCheckOk(db) ){
1839     (void)SQLITE_MISUSE_BKPT;
1840     return 0;
1841   }
1842 #endif
1843   sqlite3_mutex_enter(db->mutex);
1844   pOld = db->pTraceArg;
1845   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
1846   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
1847   db->pTraceArg = pArg;
1848   sqlite3_mutex_leave(db->mutex);
1849   return pOld;
1850 }
1851 #endif /* SQLITE_OMIT_DEPRECATED */
1852 
1853 /* Register a trace callback using the version-2 interface.
1854 */
1855 int sqlite3_trace_v2(
1856   sqlite3 *db,                               /* Trace this connection */
1857   unsigned mTrace,                           /* Mask of events to be traced */
1858   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
1859   void *pArg                                 /* Context */
1860 ){
1861 #ifdef SQLITE_ENABLE_API_ARMOR
1862   if( !sqlite3SafetyCheckOk(db) ){
1863     return SQLITE_MISUSE_BKPT;
1864   }
1865 #endif
1866   sqlite3_mutex_enter(db->mutex);
1867   if( mTrace==0 ) xTrace = 0;
1868   if( xTrace==0 ) mTrace = 0;
1869   db->mTrace = mTrace;
1870   db->xTrace = xTrace;
1871   db->pTraceArg = pArg;
1872   sqlite3_mutex_leave(db->mutex);
1873   return SQLITE_OK;
1874 }
1875 
1876 #ifndef SQLITE_OMIT_DEPRECATED
1877 /*
1878 ** Register a profile function.  The pArg from the previously registered
1879 ** profile function is returned.
1880 **
1881 ** A NULL profile function means that no profiling is executes.  A non-NULL
1882 ** profile is a pointer to a function that is invoked at the conclusion of
1883 ** each SQL statement that is run.
1884 */
1885 void *sqlite3_profile(
1886   sqlite3 *db,
1887   void (*xProfile)(void*,const char*,sqlite_uint64),
1888   void *pArg
1889 ){
1890   void *pOld;
1891 
1892 #ifdef SQLITE_ENABLE_API_ARMOR
1893   if( !sqlite3SafetyCheckOk(db) ){
1894     (void)SQLITE_MISUSE_BKPT;
1895     return 0;
1896   }
1897 #endif
1898   sqlite3_mutex_enter(db->mutex);
1899   pOld = db->pProfileArg;
1900   db->xProfile = xProfile;
1901   db->pProfileArg = pArg;
1902   sqlite3_mutex_leave(db->mutex);
1903   return pOld;
1904 }
1905 #endif /* SQLITE_OMIT_DEPRECATED */
1906 #endif /* SQLITE_OMIT_TRACE */
1907 
1908 /*
1909 ** Register a function to be invoked when a transaction commits.
1910 ** If the invoked function returns non-zero, then the commit becomes a
1911 ** rollback.
1912 */
1913 void *sqlite3_commit_hook(
1914   sqlite3 *db,              /* Attach the hook to this database */
1915   int (*xCallback)(void*),  /* Function to invoke on each commit */
1916   void *pArg                /* Argument to the function */
1917 ){
1918   void *pOld;
1919 
1920 #ifdef SQLITE_ENABLE_API_ARMOR
1921   if( !sqlite3SafetyCheckOk(db) ){
1922     (void)SQLITE_MISUSE_BKPT;
1923     return 0;
1924   }
1925 #endif
1926   sqlite3_mutex_enter(db->mutex);
1927   pOld = db->pCommitArg;
1928   db->xCommitCallback = xCallback;
1929   db->pCommitArg = pArg;
1930   sqlite3_mutex_leave(db->mutex);
1931   return pOld;
1932 }
1933 
1934 /*
1935 ** Register a callback to be invoked each time a row is updated,
1936 ** inserted or deleted using this database connection.
1937 */
1938 void *sqlite3_update_hook(
1939   sqlite3 *db,              /* Attach the hook to this database */
1940   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1941   void *pArg                /* Argument to the function */
1942 ){
1943   void *pRet;
1944 
1945 #ifdef SQLITE_ENABLE_API_ARMOR
1946   if( !sqlite3SafetyCheckOk(db) ){
1947     (void)SQLITE_MISUSE_BKPT;
1948     return 0;
1949   }
1950 #endif
1951   sqlite3_mutex_enter(db->mutex);
1952   pRet = db->pUpdateArg;
1953   db->xUpdateCallback = xCallback;
1954   db->pUpdateArg = pArg;
1955   sqlite3_mutex_leave(db->mutex);
1956   return pRet;
1957 }
1958 
1959 /*
1960 ** Register a callback to be invoked each time a transaction is rolled
1961 ** back by this database connection.
1962 */
1963 void *sqlite3_rollback_hook(
1964   sqlite3 *db,              /* Attach the hook to this database */
1965   void (*xCallback)(void*), /* Callback function */
1966   void *pArg                /* Argument to the function */
1967 ){
1968   void *pRet;
1969 
1970 #ifdef SQLITE_ENABLE_API_ARMOR
1971   if( !sqlite3SafetyCheckOk(db) ){
1972     (void)SQLITE_MISUSE_BKPT;
1973     return 0;
1974   }
1975 #endif
1976   sqlite3_mutex_enter(db->mutex);
1977   pRet = db->pRollbackArg;
1978   db->xRollbackCallback = xCallback;
1979   db->pRollbackArg = pArg;
1980   sqlite3_mutex_leave(db->mutex);
1981   return pRet;
1982 }
1983 
1984 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1985 /*
1986 ** Register a callback to be invoked each time a row is updated,
1987 ** inserted or deleted using this database connection.
1988 */
1989 void *sqlite3_preupdate_hook(
1990   sqlite3 *db,              /* Attach the hook to this database */
1991   void(*xCallback)(         /* Callback function */
1992     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
1993   void *pArg                /* First callback argument */
1994 ){
1995   void *pRet;
1996   sqlite3_mutex_enter(db->mutex);
1997   pRet = db->pPreUpdateArg;
1998   db->xPreUpdateCallback = xCallback;
1999   db->pPreUpdateArg = pArg;
2000   sqlite3_mutex_leave(db->mutex);
2001   return pRet;
2002 }
2003 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2004 
2005 #ifndef SQLITE_OMIT_WAL
2006 /*
2007 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2008 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2009 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2010 ** wal_autocheckpoint()).
2011 */
2012 int sqlite3WalDefaultHook(
2013   void *pClientData,     /* Argument */
2014   sqlite3 *db,           /* Connection */
2015   const char *zDb,       /* Database */
2016   int nFrame             /* Size of WAL */
2017 ){
2018   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2019     sqlite3BeginBenignMalloc();
2020     sqlite3_wal_checkpoint(db, zDb);
2021     sqlite3EndBenignMalloc();
2022   }
2023   return SQLITE_OK;
2024 }
2025 #endif /* SQLITE_OMIT_WAL */
2026 
2027 /*
2028 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2029 ** a database after committing a transaction if there are nFrame or
2030 ** more frames in the log file. Passing zero or a negative value as the
2031 ** nFrame parameter disables automatic checkpoints entirely.
2032 **
2033 ** The callback registered by this function replaces any existing callback
2034 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2035 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2036 ** configured by this function.
2037 */
2038 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2039 #ifdef SQLITE_OMIT_WAL
2040   UNUSED_PARAMETER(db);
2041   UNUSED_PARAMETER(nFrame);
2042 #else
2043 #ifdef SQLITE_ENABLE_API_ARMOR
2044   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2045 #endif
2046   if( nFrame>0 ){
2047     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2048   }else{
2049     sqlite3_wal_hook(db, 0, 0);
2050   }
2051 #endif
2052   return SQLITE_OK;
2053 }
2054 
2055 /*
2056 ** Register a callback to be invoked each time a transaction is written
2057 ** into the write-ahead-log by this database connection.
2058 */
2059 void *sqlite3_wal_hook(
2060   sqlite3 *db,                    /* Attach the hook to this db handle */
2061   int(*xCallback)(void *, sqlite3*, const char*, int),
2062   void *pArg                      /* First argument passed to xCallback() */
2063 ){
2064 #ifndef SQLITE_OMIT_WAL
2065   void *pRet;
2066 #ifdef SQLITE_ENABLE_API_ARMOR
2067   if( !sqlite3SafetyCheckOk(db) ){
2068     (void)SQLITE_MISUSE_BKPT;
2069     return 0;
2070   }
2071 #endif
2072   sqlite3_mutex_enter(db->mutex);
2073   pRet = db->pWalArg;
2074   db->xWalCallback = xCallback;
2075   db->pWalArg = pArg;
2076   sqlite3_mutex_leave(db->mutex);
2077   return pRet;
2078 #else
2079   return 0;
2080 #endif
2081 }
2082 
2083 /*
2084 ** Checkpoint database zDb.
2085 */
2086 int sqlite3_wal_checkpoint_v2(
2087   sqlite3 *db,                    /* Database handle */
2088   const char *zDb,                /* Name of attached database (or NULL) */
2089   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2090   int *pnLog,                     /* OUT: Size of WAL log in frames */
2091   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2092 ){
2093 #ifdef SQLITE_OMIT_WAL
2094   return SQLITE_OK;
2095 #else
2096   int rc;                         /* Return code */
2097   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2098 
2099 #ifdef SQLITE_ENABLE_API_ARMOR
2100   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2101 #endif
2102 
2103   /* Initialize the output variables to -1 in case an error occurs. */
2104   if( pnLog ) *pnLog = -1;
2105   if( pnCkpt ) *pnCkpt = -1;
2106 
2107   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2108   assert( SQLITE_CHECKPOINT_FULL==1 );
2109   assert( SQLITE_CHECKPOINT_RESTART==2 );
2110   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2111   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2112     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2113     ** mode: */
2114     return SQLITE_MISUSE;
2115   }
2116 
2117   sqlite3_mutex_enter(db->mutex);
2118   if( zDb && zDb[0] ){
2119     iDb = sqlite3FindDbName(db, zDb);
2120   }
2121   if( iDb<0 ){
2122     rc = SQLITE_ERROR;
2123     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2124   }else{
2125     db->busyHandler.nBusy = 0;
2126     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2127     sqlite3Error(db, rc);
2128   }
2129   rc = sqlite3ApiExit(db, rc);
2130 
2131   /* If there are no active statements, clear the interrupt flag at this
2132   ** point.  */
2133   if( db->nVdbeActive==0 ){
2134     db->u1.isInterrupted = 0;
2135   }
2136 
2137   sqlite3_mutex_leave(db->mutex);
2138   return rc;
2139 #endif
2140 }
2141 
2142 
2143 /*
2144 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2145 ** to contains a zero-length string, all attached databases are
2146 ** checkpointed.
2147 */
2148 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2149   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2150   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2151   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2152 }
2153 
2154 #ifndef SQLITE_OMIT_WAL
2155 /*
2156 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2157 ** not currently open in WAL mode.
2158 **
2159 ** If a transaction is open on the database being checkpointed, this
2160 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2161 ** an error occurs while running the checkpoint, an SQLite error code is
2162 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2163 **
2164 ** The mutex on database handle db should be held by the caller. The mutex
2165 ** associated with the specific b-tree being checkpointed is taken by
2166 ** this function while the checkpoint is running.
2167 **
2168 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2169 ** checkpointed. If an error is encountered it is returned immediately -
2170 ** no attempt is made to checkpoint any remaining databases.
2171 **
2172 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2173 */
2174 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2175   int rc = SQLITE_OK;             /* Return code */
2176   int i;                          /* Used to iterate through attached dbs */
2177   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2178 
2179   assert( sqlite3_mutex_held(db->mutex) );
2180   assert( !pnLog || *pnLog==-1 );
2181   assert( !pnCkpt || *pnCkpt==-1 );
2182 
2183   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2184     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2185       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2186       pnLog = 0;
2187       pnCkpt = 0;
2188       if( rc==SQLITE_BUSY ){
2189         bBusy = 1;
2190         rc = SQLITE_OK;
2191       }
2192     }
2193   }
2194 
2195   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2196 }
2197 #endif /* SQLITE_OMIT_WAL */
2198 
2199 /*
2200 ** This function returns true if main-memory should be used instead of
2201 ** a temporary file for transient pager files and statement journals.
2202 ** The value returned depends on the value of db->temp_store (runtime
2203 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2204 ** following table describes the relationship between these two values
2205 ** and this functions return value.
2206 **
2207 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2208 **   -----------------     --------------     ------------------------------
2209 **   0                     any                file      (return 0)
2210 **   1                     1                  file      (return 0)
2211 **   1                     2                  memory    (return 1)
2212 **   1                     0                  file      (return 0)
2213 **   2                     1                  file      (return 0)
2214 **   2                     2                  memory    (return 1)
2215 **   2                     0                  memory    (return 1)
2216 **   3                     any                memory    (return 1)
2217 */
2218 int sqlite3TempInMemory(const sqlite3 *db){
2219 #if SQLITE_TEMP_STORE==1
2220   return ( db->temp_store==2 );
2221 #endif
2222 #if SQLITE_TEMP_STORE==2
2223   return ( db->temp_store!=1 );
2224 #endif
2225 #if SQLITE_TEMP_STORE==3
2226   UNUSED_PARAMETER(db);
2227   return 1;
2228 #endif
2229 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2230   UNUSED_PARAMETER(db);
2231   return 0;
2232 #endif
2233 }
2234 
2235 /*
2236 ** Return UTF-8 encoded English language explanation of the most recent
2237 ** error.
2238 */
2239 const char *sqlite3_errmsg(sqlite3 *db){
2240   const char *z;
2241   if( !db ){
2242     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2243   }
2244   if( !sqlite3SafetyCheckSickOrOk(db) ){
2245     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2246   }
2247   sqlite3_mutex_enter(db->mutex);
2248   if( db->mallocFailed ){
2249     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2250   }else{
2251     testcase( db->pErr==0 );
2252     z = (char*)sqlite3_value_text(db->pErr);
2253     assert( !db->mallocFailed );
2254     if( z==0 ){
2255       z = sqlite3ErrStr(db->errCode);
2256     }
2257   }
2258   sqlite3_mutex_leave(db->mutex);
2259   return z;
2260 }
2261 
2262 #ifndef SQLITE_OMIT_UTF16
2263 /*
2264 ** Return UTF-16 encoded English language explanation of the most recent
2265 ** error.
2266 */
2267 const void *sqlite3_errmsg16(sqlite3 *db){
2268   static const u16 outOfMem[] = {
2269     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2270   };
2271   static const u16 misuse[] = {
2272     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2273     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2274     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2275     'o', 'u', 't', ' ',
2276     'o', 'f', ' ',
2277     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2278   };
2279 
2280   const void *z;
2281   if( !db ){
2282     return (void *)outOfMem;
2283   }
2284   if( !sqlite3SafetyCheckSickOrOk(db) ){
2285     return (void *)misuse;
2286   }
2287   sqlite3_mutex_enter(db->mutex);
2288   if( db->mallocFailed ){
2289     z = (void *)outOfMem;
2290   }else{
2291     z = sqlite3_value_text16(db->pErr);
2292     if( z==0 ){
2293       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2294       z = sqlite3_value_text16(db->pErr);
2295     }
2296     /* A malloc() may have failed within the call to sqlite3_value_text16()
2297     ** above. If this is the case, then the db->mallocFailed flag needs to
2298     ** be cleared before returning. Do this directly, instead of via
2299     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2300     */
2301     sqlite3OomClear(db);
2302   }
2303   sqlite3_mutex_leave(db->mutex);
2304   return z;
2305 }
2306 #endif /* SQLITE_OMIT_UTF16 */
2307 
2308 /*
2309 ** Return the most recent error code generated by an SQLite routine. If NULL is
2310 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2311 */
2312 int sqlite3_errcode(sqlite3 *db){
2313   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2314     return SQLITE_MISUSE_BKPT;
2315   }
2316   if( !db || db->mallocFailed ){
2317     return SQLITE_NOMEM_BKPT;
2318   }
2319   return db->errCode & db->errMask;
2320 }
2321 int sqlite3_extended_errcode(sqlite3 *db){
2322   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2323     return SQLITE_MISUSE_BKPT;
2324   }
2325   if( !db || db->mallocFailed ){
2326     return SQLITE_NOMEM_BKPT;
2327   }
2328   return db->errCode;
2329 }
2330 int sqlite3_system_errno(sqlite3 *db){
2331   return db ? db->iSysErrno : 0;
2332 }
2333 
2334 /*
2335 ** Return a string that describes the kind of error specified in the
2336 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2337 ** function.
2338 */
2339 const char *sqlite3_errstr(int rc){
2340   return sqlite3ErrStr(rc);
2341 }
2342 
2343 /*
2344 ** Create a new collating function for database "db".  The name is zName
2345 ** and the encoding is enc.
2346 */
2347 static int createCollation(
2348   sqlite3* db,
2349   const char *zName,
2350   u8 enc,
2351   void* pCtx,
2352   int(*xCompare)(void*,int,const void*,int,const void*),
2353   void(*xDel)(void*)
2354 ){
2355   CollSeq *pColl;
2356   int enc2;
2357 
2358   assert( sqlite3_mutex_held(db->mutex) );
2359 
2360   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2361   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2362   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2363   */
2364   enc2 = enc;
2365   testcase( enc2==SQLITE_UTF16 );
2366   testcase( enc2==SQLITE_UTF16_ALIGNED );
2367   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2368     enc2 = SQLITE_UTF16NATIVE;
2369   }
2370   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2371     return SQLITE_MISUSE_BKPT;
2372   }
2373 
2374   /* Check if this call is removing or replacing an existing collation
2375   ** sequence. If so, and there are active VMs, return busy. If there
2376   ** are no active VMs, invalidate any pre-compiled statements.
2377   */
2378   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2379   if( pColl && pColl->xCmp ){
2380     if( db->nVdbeActive ){
2381       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2382         "unable to delete/modify collation sequence due to active statements");
2383       return SQLITE_BUSY;
2384     }
2385     sqlite3ExpirePreparedStatements(db);
2386 
2387     /* If collation sequence pColl was created directly by a call to
2388     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2389     ** then any copies made by synthCollSeq() need to be invalidated.
2390     ** Also, collation destructor - CollSeq.xDel() - function may need
2391     ** to be called.
2392     */
2393     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2394       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2395       int j;
2396       for(j=0; j<3; j++){
2397         CollSeq *p = &aColl[j];
2398         if( p->enc==pColl->enc ){
2399           if( p->xDel ){
2400             p->xDel(p->pUser);
2401           }
2402           p->xCmp = 0;
2403         }
2404       }
2405     }
2406   }
2407 
2408   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2409   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2410   pColl->xCmp = xCompare;
2411   pColl->pUser = pCtx;
2412   pColl->xDel = xDel;
2413   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2414   sqlite3Error(db, SQLITE_OK);
2415   return SQLITE_OK;
2416 }
2417 
2418 
2419 /*
2420 ** This array defines hard upper bounds on limit values.  The
2421 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2422 ** #defines in sqlite3.h.
2423 */
2424 static const int aHardLimit[] = {
2425   SQLITE_MAX_LENGTH,
2426   SQLITE_MAX_SQL_LENGTH,
2427   SQLITE_MAX_COLUMN,
2428   SQLITE_MAX_EXPR_DEPTH,
2429   SQLITE_MAX_COMPOUND_SELECT,
2430   SQLITE_MAX_VDBE_OP,
2431   SQLITE_MAX_FUNCTION_ARG,
2432   SQLITE_MAX_ATTACHED,
2433   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2434   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2435   SQLITE_MAX_TRIGGER_DEPTH,
2436   SQLITE_MAX_WORKER_THREADS,
2437 };
2438 
2439 /*
2440 ** Make sure the hard limits are set to reasonable values
2441 */
2442 #if SQLITE_MAX_LENGTH<100
2443 # error SQLITE_MAX_LENGTH must be at least 100
2444 #endif
2445 #if SQLITE_MAX_SQL_LENGTH<100
2446 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2447 #endif
2448 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2449 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2450 #endif
2451 #if SQLITE_MAX_COMPOUND_SELECT<2
2452 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2453 #endif
2454 #if SQLITE_MAX_VDBE_OP<40
2455 # error SQLITE_MAX_VDBE_OP must be at least 40
2456 #endif
2457 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2458 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2459 #endif
2460 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2461 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2462 #endif
2463 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2464 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2465 #endif
2466 #if SQLITE_MAX_COLUMN>32767
2467 # error SQLITE_MAX_COLUMN must not exceed 32767
2468 #endif
2469 #if SQLITE_MAX_TRIGGER_DEPTH<1
2470 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2471 #endif
2472 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2473 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2474 #endif
2475 
2476 
2477 /*
2478 ** Change the value of a limit.  Report the old value.
2479 ** If an invalid limit index is supplied, report -1.
2480 ** Make no changes but still report the old value if the
2481 ** new limit is negative.
2482 **
2483 ** A new lower limit does not shrink existing constructs.
2484 ** It merely prevents new constructs that exceed the limit
2485 ** from forming.
2486 */
2487 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2488   int oldLimit;
2489 
2490 #ifdef SQLITE_ENABLE_API_ARMOR
2491   if( !sqlite3SafetyCheckOk(db) ){
2492     (void)SQLITE_MISUSE_BKPT;
2493     return -1;
2494   }
2495 #endif
2496 
2497   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2498   ** there is a hard upper bound set at compile-time by a C preprocessor
2499   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2500   ** "_MAX_".)
2501   */
2502   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2503   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2504   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2505   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2506   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2507   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2508   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2509   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2510   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2511                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2512   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2513   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2514   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2515   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2516 
2517 
2518   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2519     return -1;
2520   }
2521   oldLimit = db->aLimit[limitId];
2522   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2523     if( newLimit>aHardLimit[limitId] ){
2524       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2525     }
2526     db->aLimit[limitId] = newLimit;
2527   }
2528   return oldLimit;                     /* IMP: R-53341-35419 */
2529 }
2530 
2531 /*
2532 ** This function is used to parse both URIs and non-URI filenames passed by the
2533 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2534 ** URIs specified as part of ATTACH statements.
2535 **
2536 ** The first argument to this function is the name of the VFS to use (or
2537 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2538 ** query parameter. The second argument contains the URI (or non-URI filename)
2539 ** itself. When this function is called the *pFlags variable should contain
2540 ** the default flags to open the database handle with. The value stored in
2541 ** *pFlags may be updated before returning if the URI filename contains
2542 ** "cache=xxx" or "mode=xxx" query parameters.
2543 **
2544 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2545 ** the VFS that should be used to open the database file. *pzFile is set to
2546 ** point to a buffer containing the name of the file to open. It is the
2547 ** responsibility of the caller to eventually call sqlite3_free() to release
2548 ** this buffer.
2549 **
2550 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2551 ** may be set to point to a buffer containing an English language error
2552 ** message. It is the responsibility of the caller to eventually release
2553 ** this buffer by calling sqlite3_free().
2554 */
2555 int sqlite3ParseUri(
2556   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2557   const char *zUri,               /* Nul-terminated URI to parse */
2558   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2559   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2560   char **pzFile,                  /* OUT: Filename component of URI */
2561   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2562 ){
2563   int rc = SQLITE_OK;
2564   unsigned int flags = *pFlags;
2565   const char *zVfs = zDefaultVfs;
2566   char *zFile;
2567   char c;
2568   int nUri = sqlite3Strlen30(zUri);
2569 
2570   assert( *pzErrMsg==0 );
2571 
2572   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2573             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2574    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2575   ){
2576     char *zOpt;
2577     int eState;                   /* Parser state when parsing URI */
2578     int iIn;                      /* Input character index */
2579     int iOut = 0;                 /* Output character index */
2580     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2581 
2582     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2583     ** method that there may be extra parameters following the file-name.  */
2584     flags |= SQLITE_OPEN_URI;
2585 
2586     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2587     zFile = sqlite3_malloc64(nByte);
2588     if( !zFile ) return SQLITE_NOMEM_BKPT;
2589 
2590     iIn = 5;
2591 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2592     if( strncmp(zUri+5, "///", 3)==0 ){
2593       iIn = 7;
2594       /* The following condition causes URIs with five leading / characters
2595       ** like file://///host/path to be converted into UNCs like //host/path.
2596       ** The correct URI for that UNC has only two or four leading / characters
2597       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2598       ** common error, we are told, so we handle it as a special case. */
2599       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2600     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2601       iIn = 16;
2602     }
2603 #else
2604     /* Discard the scheme and authority segments of the URI. */
2605     if( zUri[5]=='/' && zUri[6]=='/' ){
2606       iIn = 7;
2607       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2608       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2609         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2610             iIn-7, &zUri[7]);
2611         rc = SQLITE_ERROR;
2612         goto parse_uri_out;
2613       }
2614     }
2615 #endif
2616 
2617     /* Copy the filename and any query parameters into the zFile buffer.
2618     ** Decode %HH escape codes along the way.
2619     **
2620     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2621     ** on the parsing context. As follows:
2622     **
2623     **   0: Parsing file-name.
2624     **   1: Parsing name section of a name=value query parameter.
2625     **   2: Parsing value section of a name=value query parameter.
2626     */
2627     eState = 0;
2628     while( (c = zUri[iIn])!=0 && c!='#' ){
2629       iIn++;
2630       if( c=='%'
2631        && sqlite3Isxdigit(zUri[iIn])
2632        && sqlite3Isxdigit(zUri[iIn+1])
2633       ){
2634         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2635         octet += sqlite3HexToInt(zUri[iIn++]);
2636 
2637         assert( octet>=0 && octet<256 );
2638         if( octet==0 ){
2639 #ifndef SQLITE_ENABLE_URI_00_ERROR
2640           /* This branch is taken when "%00" appears within the URI. In this
2641           ** case we ignore all text in the remainder of the path, name or
2642           ** value currently being parsed. So ignore the current character
2643           ** and skip to the next "?", "=" or "&", as appropriate. */
2644           while( (c = zUri[iIn])!=0 && c!='#'
2645               && (eState!=0 || c!='?')
2646               && (eState!=1 || (c!='=' && c!='&'))
2647               && (eState!=2 || c!='&')
2648           ){
2649             iIn++;
2650           }
2651           continue;
2652 #else
2653           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2654           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2655           rc = SQLITE_ERROR;
2656           goto parse_uri_out;
2657 #endif
2658         }
2659         c = octet;
2660       }else if( eState==1 && (c=='&' || c=='=') ){
2661         if( zFile[iOut-1]==0 ){
2662           /* An empty option name. Ignore this option altogether. */
2663           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2664           continue;
2665         }
2666         if( c=='&' ){
2667           zFile[iOut++] = '\0';
2668         }else{
2669           eState = 2;
2670         }
2671         c = 0;
2672       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2673         c = 0;
2674         eState = 1;
2675       }
2676       zFile[iOut++] = c;
2677     }
2678     if( eState==1 ) zFile[iOut++] = '\0';
2679     zFile[iOut++] = '\0';
2680     zFile[iOut++] = '\0';
2681 
2682     /* Check if there were any options specified that should be interpreted
2683     ** here. Options that are interpreted here include "vfs" and those that
2684     ** correspond to flags that may be passed to the sqlite3_open_v2()
2685     ** method. */
2686     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2687     while( zOpt[0] ){
2688       int nOpt = sqlite3Strlen30(zOpt);
2689       char *zVal = &zOpt[nOpt+1];
2690       int nVal = sqlite3Strlen30(zVal);
2691 
2692       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2693         zVfs = zVal;
2694       }else{
2695         struct OpenMode {
2696           const char *z;
2697           int mode;
2698         } *aMode = 0;
2699         char *zModeType = 0;
2700         int mask = 0;
2701         int limit = 0;
2702 
2703         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2704           static struct OpenMode aCacheMode[] = {
2705             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2706             { "private", SQLITE_OPEN_PRIVATECACHE },
2707             { 0, 0 }
2708           };
2709 
2710           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2711           aMode = aCacheMode;
2712           limit = mask;
2713           zModeType = "cache";
2714         }
2715         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2716           static struct OpenMode aOpenMode[] = {
2717             { "ro",  SQLITE_OPEN_READONLY },
2718             { "rw",  SQLITE_OPEN_READWRITE },
2719             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2720             { "memory", SQLITE_OPEN_MEMORY },
2721             { 0, 0 }
2722           };
2723 
2724           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2725                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2726           aMode = aOpenMode;
2727           limit = mask & flags;
2728           zModeType = "access";
2729         }
2730 
2731         if( aMode ){
2732           int i;
2733           int mode = 0;
2734           for(i=0; aMode[i].z; i++){
2735             const char *z = aMode[i].z;
2736             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2737               mode = aMode[i].mode;
2738               break;
2739             }
2740           }
2741           if( mode==0 ){
2742             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2743             rc = SQLITE_ERROR;
2744             goto parse_uri_out;
2745           }
2746           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2747             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2748                                         zModeType, zVal);
2749             rc = SQLITE_PERM;
2750             goto parse_uri_out;
2751           }
2752           flags = (flags & ~mask) | mode;
2753         }
2754       }
2755 
2756       zOpt = &zVal[nVal+1];
2757     }
2758 
2759   }else{
2760     zFile = sqlite3_malloc64(nUri+2);
2761     if( !zFile ) return SQLITE_NOMEM_BKPT;
2762     if( nUri ){
2763       memcpy(zFile, zUri, nUri);
2764     }
2765     zFile[nUri] = '\0';
2766     zFile[nUri+1] = '\0';
2767     flags &= ~SQLITE_OPEN_URI;
2768   }
2769 
2770   *ppVfs = sqlite3_vfs_find(zVfs);
2771   if( *ppVfs==0 ){
2772     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2773     rc = SQLITE_ERROR;
2774   }
2775  parse_uri_out:
2776   if( rc!=SQLITE_OK ){
2777     sqlite3_free(zFile);
2778     zFile = 0;
2779   }
2780   *pFlags = flags;
2781   *pzFile = zFile;
2782   return rc;
2783 }
2784 
2785 
2786 /*
2787 ** This routine does the work of opening a database on behalf of
2788 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2789 ** is UTF-8 encoded.
2790 */
2791 static int openDatabase(
2792   const char *zFilename, /* Database filename UTF-8 encoded */
2793   sqlite3 **ppDb,        /* OUT: Returned database handle */
2794   unsigned int flags,    /* Operational flags */
2795   const char *zVfs       /* Name of the VFS to use */
2796 ){
2797   sqlite3 *db;                    /* Store allocated handle here */
2798   int rc;                         /* Return code */
2799   int isThreadsafe;               /* True for threadsafe connections */
2800   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2801   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2802 
2803 #ifdef SQLITE_ENABLE_API_ARMOR
2804   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2805 #endif
2806   *ppDb = 0;
2807 #ifndef SQLITE_OMIT_AUTOINIT
2808   rc = sqlite3_initialize();
2809   if( rc ) return rc;
2810 #endif
2811 
2812   /* Only allow sensible combinations of bits in the flags argument.
2813   ** Throw an error if any non-sense combination is used.  If we
2814   ** do not block illegal combinations here, it could trigger
2815   ** assert() statements in deeper layers.  Sensible combinations
2816   ** are:
2817   **
2818   **  1:  SQLITE_OPEN_READONLY
2819   **  2:  SQLITE_OPEN_READWRITE
2820   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2821   */
2822   assert( SQLITE_OPEN_READONLY  == 0x01 );
2823   assert( SQLITE_OPEN_READWRITE == 0x02 );
2824   assert( SQLITE_OPEN_CREATE    == 0x04 );
2825   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2826   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2827   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2828   if( ((1<<(flags&7)) & 0x46)==0 ){
2829     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2830   }
2831 
2832   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2833     isThreadsafe = 0;
2834   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2835     isThreadsafe = 0;
2836   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2837     isThreadsafe = 1;
2838   }else{
2839     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2840   }
2841   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2842     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2843   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2844     flags |= SQLITE_OPEN_SHAREDCACHE;
2845   }
2846 
2847   /* Remove harmful bits from the flags parameter
2848   **
2849   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2850   ** dealt with in the previous code block.  Besides these, the only
2851   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2852   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2853   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2854   ** off all other flags.
2855   */
2856   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2857                SQLITE_OPEN_EXCLUSIVE |
2858                SQLITE_OPEN_MAIN_DB |
2859                SQLITE_OPEN_TEMP_DB |
2860                SQLITE_OPEN_TRANSIENT_DB |
2861                SQLITE_OPEN_MAIN_JOURNAL |
2862                SQLITE_OPEN_TEMP_JOURNAL |
2863                SQLITE_OPEN_SUBJOURNAL |
2864                SQLITE_OPEN_MASTER_JOURNAL |
2865                SQLITE_OPEN_NOMUTEX |
2866                SQLITE_OPEN_FULLMUTEX |
2867                SQLITE_OPEN_WAL
2868              );
2869 
2870   /* Allocate the sqlite data structure */
2871   db = sqlite3MallocZero( sizeof(sqlite3) );
2872   if( db==0 ) goto opendb_out;
2873   if( isThreadsafe ){
2874     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2875     if( db->mutex==0 ){
2876       sqlite3_free(db);
2877       db = 0;
2878       goto opendb_out;
2879     }
2880   }
2881   sqlite3_mutex_enter(db->mutex);
2882   db->errMask = 0xff;
2883   db->nDb = 2;
2884   db->magic = SQLITE_MAGIC_BUSY;
2885   db->aDb = db->aDbStatic;
2886 
2887   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2888   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2889   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2890   db->autoCommit = 1;
2891   db->nextAutovac = -1;
2892   db->szMmap = sqlite3GlobalConfig.szMmap;
2893   db->nextPagesize = 0;
2894   db->nMaxSorterMmap = 0x7FFFFFFF;
2895   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2896 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2897                  | SQLITE_AutoIndex
2898 #endif
2899 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2900                  | SQLITE_CkptFullFSync
2901 #endif
2902 #if SQLITE_DEFAULT_FILE_FORMAT<4
2903                  | SQLITE_LegacyFileFmt
2904 #endif
2905 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2906                  | SQLITE_LoadExtension
2907 #endif
2908 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2909                  | SQLITE_RecTriggers
2910 #endif
2911 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2912                  | SQLITE_ForeignKeys
2913 #endif
2914 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2915                  | SQLITE_ReverseOrder
2916 #endif
2917 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2918                  | SQLITE_CellSizeCk
2919 #endif
2920 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
2921                  | SQLITE_Fts3Tokenizer
2922 #endif
2923 #if defined(SQLITE_ENABLE_QPSG)
2924                  | SQLITE_EnableQPSG
2925 #endif
2926       ;
2927   sqlite3HashInit(&db->aCollSeq);
2928 #ifndef SQLITE_OMIT_VIRTUALTABLE
2929   sqlite3HashInit(&db->aModule);
2930 #endif
2931 
2932   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2933   ** and UTF-16, so add a version for each to avoid any unnecessary
2934   ** conversions. The only error that can occur here is a malloc() failure.
2935   **
2936   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2937   ** functions:
2938   */
2939   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2940   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2941   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2942   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2943   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2944   if( db->mallocFailed ){
2945     goto opendb_out;
2946   }
2947   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2948   ** strings is BINARY.
2949   */
2950   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2951   assert( db->pDfltColl!=0 );
2952 
2953   /* Parse the filename/URI argument. */
2954   db->openFlags = flags;
2955   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2956   if( rc!=SQLITE_OK ){
2957     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2958     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2959     sqlite3_free(zErrMsg);
2960     goto opendb_out;
2961   }
2962 
2963   /* Open the backend database driver */
2964   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2965                         flags | SQLITE_OPEN_MAIN_DB);
2966   if( rc!=SQLITE_OK ){
2967     if( rc==SQLITE_IOERR_NOMEM ){
2968       rc = SQLITE_NOMEM_BKPT;
2969     }
2970     sqlite3Error(db, rc);
2971     goto opendb_out;
2972   }
2973   sqlite3BtreeEnter(db->aDb[0].pBt);
2974   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2975   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2976   sqlite3BtreeLeave(db->aDb[0].pBt);
2977   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2978 
2979   /* The default safety_level for the main database is FULL; for the temp
2980   ** database it is OFF. This matches the pager layer defaults.
2981   */
2982   db->aDb[0].zDbSName = "main";
2983   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
2984   db->aDb[1].zDbSName = "temp";
2985   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
2986 
2987   db->magic = SQLITE_MAGIC_OPEN;
2988   if( db->mallocFailed ){
2989     goto opendb_out;
2990   }
2991 
2992   /* Register all built-in functions, but do not attempt to read the
2993   ** database schema yet. This is delayed until the first time the database
2994   ** is accessed.
2995   */
2996   sqlite3Error(db, SQLITE_OK);
2997   sqlite3RegisterPerConnectionBuiltinFunctions(db);
2998   rc = sqlite3_errcode(db);
2999 
3000 #ifdef SQLITE_ENABLE_FTS5
3001   /* Register any built-in FTS5 module before loading the automatic
3002   ** extensions. This allows automatic extensions to register FTS5
3003   ** tokenizers and auxiliary functions.  */
3004   if( !db->mallocFailed && rc==SQLITE_OK ){
3005     rc = sqlite3Fts5Init(db);
3006   }
3007 #endif
3008 
3009   /* Load automatic extensions - extensions that have been registered
3010   ** using the sqlite3_automatic_extension() API.
3011   */
3012   if( rc==SQLITE_OK ){
3013     sqlite3AutoLoadExtensions(db);
3014     rc = sqlite3_errcode(db);
3015     if( rc!=SQLITE_OK ){
3016       goto opendb_out;
3017     }
3018   }
3019 
3020 #ifdef SQLITE_ENABLE_FTS1
3021   if( !db->mallocFailed ){
3022     extern int sqlite3Fts1Init(sqlite3*);
3023     rc = sqlite3Fts1Init(db);
3024   }
3025 #endif
3026 
3027 #ifdef SQLITE_ENABLE_FTS2
3028   if( !db->mallocFailed && rc==SQLITE_OK ){
3029     extern int sqlite3Fts2Init(sqlite3*);
3030     rc = sqlite3Fts2Init(db);
3031   }
3032 #endif
3033 
3034 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3035   if( !db->mallocFailed && rc==SQLITE_OK ){
3036     rc = sqlite3Fts3Init(db);
3037   }
3038 #endif
3039 
3040 #ifdef SQLITE_ENABLE_ICU
3041   if( !db->mallocFailed && rc==SQLITE_OK ){
3042     rc = sqlite3IcuInit(db);
3043   }
3044 #endif
3045 
3046 #ifdef SQLITE_ENABLE_RTREE
3047   if( !db->mallocFailed && rc==SQLITE_OK){
3048     rc = sqlite3RtreeInit(db);
3049   }
3050 #endif
3051 
3052 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3053   if( !db->mallocFailed && rc==SQLITE_OK){
3054     rc = sqlite3DbstatRegister(db);
3055   }
3056 #endif
3057 
3058 #ifdef SQLITE_ENABLE_JSON1
3059   if( !db->mallocFailed && rc==SQLITE_OK){
3060     rc = sqlite3Json1Init(db);
3061   }
3062 #endif
3063 
3064 #ifdef SQLITE_ENABLE_STMTVTAB
3065   if( !db->mallocFailed && rc==SQLITE_OK){
3066     rc = sqlite3StmtVtabInit(db);
3067   }
3068 #endif
3069 
3070   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3071   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3072   ** mode.  Doing nothing at all also makes NORMAL the default.
3073   */
3074 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3075   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3076   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3077                           SQLITE_DEFAULT_LOCKING_MODE);
3078 #endif
3079 
3080   if( rc ) sqlite3Error(db, rc);
3081 
3082   /* Enable the lookaside-malloc subsystem */
3083   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3084                         sqlite3GlobalConfig.nLookaside);
3085 
3086   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3087 
3088 opendb_out:
3089   if( db ){
3090     assert( db->mutex!=0 || isThreadsafe==0
3091            || sqlite3GlobalConfig.bFullMutex==0 );
3092     sqlite3_mutex_leave(db->mutex);
3093   }
3094   rc = sqlite3_errcode(db);
3095   assert( db!=0 || rc==SQLITE_NOMEM );
3096   if( rc==SQLITE_NOMEM ){
3097     sqlite3_close(db);
3098     db = 0;
3099   }else if( rc!=SQLITE_OK ){
3100     db->magic = SQLITE_MAGIC_SICK;
3101   }
3102   *ppDb = db;
3103 #ifdef SQLITE_ENABLE_SQLLOG
3104   if( sqlite3GlobalConfig.xSqllog ){
3105     /* Opening a db handle. Fourth parameter is passed 0. */
3106     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3107     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3108   }
3109 #endif
3110 #if defined(SQLITE_HAS_CODEC)
3111   if( rc==SQLITE_OK ){
3112     const char *zKey;
3113     if( (zKey = sqlite3_uri_parameter(zOpen, "hexkey"))!=0 && zKey[0] ){
3114       u8 iByte;
3115       int i;
3116       char zDecoded[40];
3117       for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
3118         iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
3119         if( (i&1)!=0 ) zDecoded[i/2] = iByte;
3120       }
3121       sqlite3_key_v2(db, 0, zDecoded, i/2);
3122     }else if( (zKey = sqlite3_uri_parameter(zOpen, "key"))!=0 ){
3123       sqlite3_key_v2(db, 0, zKey, sqlite3Strlen30(zKey));
3124     }
3125   }
3126 #endif
3127   sqlite3_free(zOpen);
3128   return rc & 0xff;
3129 }
3130 
3131 /*
3132 ** Open a new database handle.
3133 */
3134 int sqlite3_open(
3135   const char *zFilename,
3136   sqlite3 **ppDb
3137 ){
3138   return openDatabase(zFilename, ppDb,
3139                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3140 }
3141 int sqlite3_open_v2(
3142   const char *filename,   /* Database filename (UTF-8) */
3143   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3144   int flags,              /* Flags */
3145   const char *zVfs        /* Name of VFS module to use */
3146 ){
3147   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3148 }
3149 
3150 #ifndef SQLITE_OMIT_UTF16
3151 /*
3152 ** Open a new database handle.
3153 */
3154 int sqlite3_open16(
3155   const void *zFilename,
3156   sqlite3 **ppDb
3157 ){
3158   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3159   sqlite3_value *pVal;
3160   int rc;
3161 
3162 #ifdef SQLITE_ENABLE_API_ARMOR
3163   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3164 #endif
3165   *ppDb = 0;
3166 #ifndef SQLITE_OMIT_AUTOINIT
3167   rc = sqlite3_initialize();
3168   if( rc ) return rc;
3169 #endif
3170   if( zFilename==0 ) zFilename = "\000\000";
3171   pVal = sqlite3ValueNew(0);
3172   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3173   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3174   if( zFilename8 ){
3175     rc = openDatabase(zFilename8, ppDb,
3176                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3177     assert( *ppDb || rc==SQLITE_NOMEM );
3178     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3179       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3180     }
3181   }else{
3182     rc = SQLITE_NOMEM_BKPT;
3183   }
3184   sqlite3ValueFree(pVal);
3185 
3186   return rc & 0xff;
3187 }
3188 #endif /* SQLITE_OMIT_UTF16 */
3189 
3190 /*
3191 ** Register a new collation sequence with the database handle db.
3192 */
3193 int sqlite3_create_collation(
3194   sqlite3* db,
3195   const char *zName,
3196   int enc,
3197   void* pCtx,
3198   int(*xCompare)(void*,int,const void*,int,const void*)
3199 ){
3200   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3201 }
3202 
3203 /*
3204 ** Register a new collation sequence with the database handle db.
3205 */
3206 int sqlite3_create_collation_v2(
3207   sqlite3* db,
3208   const char *zName,
3209   int enc,
3210   void* pCtx,
3211   int(*xCompare)(void*,int,const void*,int,const void*),
3212   void(*xDel)(void*)
3213 ){
3214   int rc;
3215 
3216 #ifdef SQLITE_ENABLE_API_ARMOR
3217   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3218 #endif
3219   sqlite3_mutex_enter(db->mutex);
3220   assert( !db->mallocFailed );
3221   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3222   rc = sqlite3ApiExit(db, rc);
3223   sqlite3_mutex_leave(db->mutex);
3224   return rc;
3225 }
3226 
3227 #ifndef SQLITE_OMIT_UTF16
3228 /*
3229 ** Register a new collation sequence with the database handle db.
3230 */
3231 int sqlite3_create_collation16(
3232   sqlite3* db,
3233   const void *zName,
3234   int enc,
3235   void* pCtx,
3236   int(*xCompare)(void*,int,const void*,int,const void*)
3237 ){
3238   int rc = SQLITE_OK;
3239   char *zName8;
3240 
3241 #ifdef SQLITE_ENABLE_API_ARMOR
3242   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3243 #endif
3244   sqlite3_mutex_enter(db->mutex);
3245   assert( !db->mallocFailed );
3246   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3247   if( zName8 ){
3248     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3249     sqlite3DbFree(db, zName8);
3250   }
3251   rc = sqlite3ApiExit(db, rc);
3252   sqlite3_mutex_leave(db->mutex);
3253   return rc;
3254 }
3255 #endif /* SQLITE_OMIT_UTF16 */
3256 
3257 /*
3258 ** Register a collation sequence factory callback with the database handle
3259 ** db. Replace any previously installed collation sequence factory.
3260 */
3261 int sqlite3_collation_needed(
3262   sqlite3 *db,
3263   void *pCollNeededArg,
3264   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3265 ){
3266 #ifdef SQLITE_ENABLE_API_ARMOR
3267   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3268 #endif
3269   sqlite3_mutex_enter(db->mutex);
3270   db->xCollNeeded = xCollNeeded;
3271   db->xCollNeeded16 = 0;
3272   db->pCollNeededArg = pCollNeededArg;
3273   sqlite3_mutex_leave(db->mutex);
3274   return SQLITE_OK;
3275 }
3276 
3277 #ifndef SQLITE_OMIT_UTF16
3278 /*
3279 ** Register a collation sequence factory callback with the database handle
3280 ** db. Replace any previously installed collation sequence factory.
3281 */
3282 int sqlite3_collation_needed16(
3283   sqlite3 *db,
3284   void *pCollNeededArg,
3285   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3286 ){
3287 #ifdef SQLITE_ENABLE_API_ARMOR
3288   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3289 #endif
3290   sqlite3_mutex_enter(db->mutex);
3291   db->xCollNeeded = 0;
3292   db->xCollNeeded16 = xCollNeeded16;
3293   db->pCollNeededArg = pCollNeededArg;
3294   sqlite3_mutex_leave(db->mutex);
3295   return SQLITE_OK;
3296 }
3297 #endif /* SQLITE_OMIT_UTF16 */
3298 
3299 #ifndef SQLITE_OMIT_DEPRECATED
3300 /*
3301 ** This function is now an anachronism. It used to be used to recover from a
3302 ** malloc() failure, but SQLite now does this automatically.
3303 */
3304 int sqlite3_global_recover(void){
3305   return SQLITE_OK;
3306 }
3307 #endif
3308 
3309 /*
3310 ** Test to see whether or not the database connection is in autocommit
3311 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3312 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3313 ** by the next COMMIT or ROLLBACK.
3314 */
3315 int sqlite3_get_autocommit(sqlite3 *db){
3316 #ifdef SQLITE_ENABLE_API_ARMOR
3317   if( !sqlite3SafetyCheckOk(db) ){
3318     (void)SQLITE_MISUSE_BKPT;
3319     return 0;
3320   }
3321 #endif
3322   return db->autoCommit;
3323 }
3324 
3325 /*
3326 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3327 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3328 ** constants.  They serve two purposes:
3329 **
3330 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3331 **       to detect when version error conditions occurs.
3332 **
3333 **   2.  Invoke sqlite3_log() to provide the source code location where
3334 **       a low-level error is first detected.
3335 */
3336 static int reportError(int iErr, int lineno, const char *zType){
3337   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3338               zType, lineno, 20+sqlite3_sourceid());
3339   return iErr;
3340 }
3341 int sqlite3CorruptError(int lineno){
3342   testcase( sqlite3GlobalConfig.xLog!=0 );
3343   return reportError(SQLITE_CORRUPT, lineno, "database corruption");
3344 }
3345 int sqlite3MisuseError(int lineno){
3346   testcase( sqlite3GlobalConfig.xLog!=0 );
3347   return reportError(SQLITE_MISUSE, lineno, "misuse");
3348 }
3349 int sqlite3CantopenError(int lineno){
3350   testcase( sqlite3GlobalConfig.xLog!=0 );
3351   return reportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3352 }
3353 #ifdef SQLITE_DEBUG
3354 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3355   char zMsg[100];
3356   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3357   testcase( sqlite3GlobalConfig.xLog!=0 );
3358   return reportError(SQLITE_CORRUPT, lineno, zMsg);
3359 }
3360 int sqlite3NomemError(int lineno){
3361   testcase( sqlite3GlobalConfig.xLog!=0 );
3362   return reportError(SQLITE_NOMEM, lineno, "OOM");
3363 }
3364 int sqlite3IoerrnomemError(int lineno){
3365   testcase( sqlite3GlobalConfig.xLog!=0 );
3366   return reportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3367 }
3368 #endif
3369 
3370 #ifndef SQLITE_OMIT_DEPRECATED
3371 /*
3372 ** This is a convenience routine that makes sure that all thread-specific
3373 ** data for this thread has been deallocated.
3374 **
3375 ** SQLite no longer uses thread-specific data so this routine is now a
3376 ** no-op.  It is retained for historical compatibility.
3377 */
3378 void sqlite3_thread_cleanup(void){
3379 }
3380 #endif
3381 
3382 /*
3383 ** Return meta information about a specific column of a database table.
3384 ** See comment in sqlite3.h (sqlite.h.in) for details.
3385 */
3386 int sqlite3_table_column_metadata(
3387   sqlite3 *db,                /* Connection handle */
3388   const char *zDbName,        /* Database name or NULL */
3389   const char *zTableName,     /* Table name */
3390   const char *zColumnName,    /* Column name */
3391   char const **pzDataType,    /* OUTPUT: Declared data type */
3392   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3393   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3394   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3395   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3396 ){
3397   int rc;
3398   char *zErrMsg = 0;
3399   Table *pTab = 0;
3400   Column *pCol = 0;
3401   int iCol = 0;
3402   char const *zDataType = 0;
3403   char const *zCollSeq = 0;
3404   int notnull = 0;
3405   int primarykey = 0;
3406   int autoinc = 0;
3407 
3408 
3409 #ifdef SQLITE_ENABLE_API_ARMOR
3410   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3411     return SQLITE_MISUSE_BKPT;
3412   }
3413 #endif
3414 
3415   /* Ensure the database schema has been loaded */
3416   sqlite3_mutex_enter(db->mutex);
3417   sqlite3BtreeEnterAll(db);
3418   rc = sqlite3Init(db, &zErrMsg);
3419   if( SQLITE_OK!=rc ){
3420     goto error_out;
3421   }
3422 
3423   /* Locate the table in question */
3424   pTab = sqlite3FindTable(db, zTableName, zDbName);
3425   if( !pTab || pTab->pSelect ){
3426     pTab = 0;
3427     goto error_out;
3428   }
3429 
3430   /* Find the column for which info is requested */
3431   if( zColumnName==0 ){
3432     /* Query for existance of table only */
3433   }else{
3434     for(iCol=0; iCol<pTab->nCol; iCol++){
3435       pCol = &pTab->aCol[iCol];
3436       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3437         break;
3438       }
3439     }
3440     if( iCol==pTab->nCol ){
3441       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3442         iCol = pTab->iPKey;
3443         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3444       }else{
3445         pTab = 0;
3446         goto error_out;
3447       }
3448     }
3449   }
3450 
3451   /* The following block stores the meta information that will be returned
3452   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3453   ** and autoinc. At this point there are two possibilities:
3454   **
3455   **     1. The specified column name was rowid", "oid" or "_rowid_"
3456   **        and there is no explicitly declared IPK column.
3457   **
3458   **     2. The table is not a view and the column name identified an
3459   **        explicitly declared column. Copy meta information from *pCol.
3460   */
3461   if( pCol ){
3462     zDataType = sqlite3ColumnType(pCol,0);
3463     zCollSeq = pCol->zColl;
3464     notnull = pCol->notNull!=0;
3465     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3466     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3467   }else{
3468     zDataType = "INTEGER";
3469     primarykey = 1;
3470   }
3471   if( !zCollSeq ){
3472     zCollSeq = sqlite3StrBINARY;
3473   }
3474 
3475 error_out:
3476   sqlite3BtreeLeaveAll(db);
3477 
3478   /* Whether the function call succeeded or failed, set the output parameters
3479   ** to whatever their local counterparts contain. If an error did occur,
3480   ** this has the effect of zeroing all output parameters.
3481   */
3482   if( pzDataType ) *pzDataType = zDataType;
3483   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3484   if( pNotNull ) *pNotNull = notnull;
3485   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3486   if( pAutoinc ) *pAutoinc = autoinc;
3487 
3488   if( SQLITE_OK==rc && !pTab ){
3489     sqlite3DbFree(db, zErrMsg);
3490     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3491         zColumnName);
3492     rc = SQLITE_ERROR;
3493   }
3494   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3495   sqlite3DbFree(db, zErrMsg);
3496   rc = sqlite3ApiExit(db, rc);
3497   sqlite3_mutex_leave(db->mutex);
3498   return rc;
3499 }
3500 
3501 /*
3502 ** Sleep for a little while.  Return the amount of time slept.
3503 */
3504 int sqlite3_sleep(int ms){
3505   sqlite3_vfs *pVfs;
3506   int rc;
3507   pVfs = sqlite3_vfs_find(0);
3508   if( pVfs==0 ) return 0;
3509 
3510   /* This function works in milliseconds, but the underlying OsSleep()
3511   ** API uses microseconds. Hence the 1000's.
3512   */
3513   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3514   return rc;
3515 }
3516 
3517 /*
3518 ** Enable or disable the extended result codes.
3519 */
3520 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3521 #ifdef SQLITE_ENABLE_API_ARMOR
3522   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3523 #endif
3524   sqlite3_mutex_enter(db->mutex);
3525   db->errMask = onoff ? 0xffffffff : 0xff;
3526   sqlite3_mutex_leave(db->mutex);
3527   return SQLITE_OK;
3528 }
3529 
3530 /*
3531 ** Invoke the xFileControl method on a particular database.
3532 */
3533 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3534   int rc = SQLITE_ERROR;
3535   Btree *pBtree;
3536 
3537 #ifdef SQLITE_ENABLE_API_ARMOR
3538   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3539 #endif
3540   sqlite3_mutex_enter(db->mutex);
3541   pBtree = sqlite3DbNameToBtree(db, zDbName);
3542   if( pBtree ){
3543     Pager *pPager;
3544     sqlite3_file *fd;
3545     sqlite3BtreeEnter(pBtree);
3546     pPager = sqlite3BtreePager(pBtree);
3547     assert( pPager!=0 );
3548     fd = sqlite3PagerFile(pPager);
3549     assert( fd!=0 );
3550     if( op==SQLITE_FCNTL_FILE_POINTER ){
3551       *(sqlite3_file**)pArg = fd;
3552       rc = SQLITE_OK;
3553     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3554       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3555       rc = SQLITE_OK;
3556     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3557       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3558       rc = SQLITE_OK;
3559     }else if( fd->pMethods ){
3560       rc = sqlite3OsFileControl(fd, op, pArg);
3561     }else{
3562       rc = SQLITE_NOTFOUND;
3563     }
3564     sqlite3BtreeLeave(pBtree);
3565   }
3566   sqlite3_mutex_leave(db->mutex);
3567   return rc;
3568 }
3569 
3570 /*
3571 ** Interface to the testing logic.
3572 */
3573 int sqlite3_test_control(int op, ...){
3574   int rc = 0;
3575 #ifdef SQLITE_UNTESTABLE
3576   UNUSED_PARAMETER(op);
3577 #else
3578   va_list ap;
3579   va_start(ap, op);
3580   switch( op ){
3581 
3582     /*
3583     ** Save the current state of the PRNG.
3584     */
3585     case SQLITE_TESTCTRL_PRNG_SAVE: {
3586       sqlite3PrngSaveState();
3587       break;
3588     }
3589 
3590     /*
3591     ** Restore the state of the PRNG to the last state saved using
3592     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3593     ** this verb acts like PRNG_RESET.
3594     */
3595     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3596       sqlite3PrngRestoreState();
3597       break;
3598     }
3599 
3600     /*
3601     ** Reset the PRNG back to its uninitialized state.  The next call
3602     ** to sqlite3_randomness() will reseed the PRNG using a single call
3603     ** to the xRandomness method of the default VFS.
3604     */
3605     case SQLITE_TESTCTRL_PRNG_RESET: {
3606       sqlite3_randomness(0,0);
3607       break;
3608     }
3609 
3610     /*
3611     **  sqlite3_test_control(BITVEC_TEST, size, program)
3612     **
3613     ** Run a test against a Bitvec object of size.  The program argument
3614     ** is an array of integers that defines the test.  Return -1 on a
3615     ** memory allocation error, 0 on success, or non-zero for an error.
3616     ** See the sqlite3BitvecBuiltinTest() for additional information.
3617     */
3618     case SQLITE_TESTCTRL_BITVEC_TEST: {
3619       int sz = va_arg(ap, int);
3620       int *aProg = va_arg(ap, int*);
3621       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3622       break;
3623     }
3624 
3625     /*
3626     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3627     **
3628     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3629     ** if xCallback is not NULL.
3630     **
3631     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3632     ** is called immediately after installing the new callback and the return
3633     ** value from sqlite3FaultSim(0) becomes the return from
3634     ** sqlite3_test_control().
3635     */
3636     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3637       /* MSVC is picky about pulling func ptrs from va lists.
3638       ** http://support.microsoft.com/kb/47961
3639       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3640       */
3641       typedef int(*TESTCALLBACKFUNC_t)(int);
3642       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3643       rc = sqlite3FaultSim(0);
3644       break;
3645     }
3646 
3647     /*
3648     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3649     **
3650     ** Register hooks to call to indicate which malloc() failures
3651     ** are benign.
3652     */
3653     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3654       typedef void (*void_function)(void);
3655       void_function xBenignBegin;
3656       void_function xBenignEnd;
3657       xBenignBegin = va_arg(ap, void_function);
3658       xBenignEnd = va_arg(ap, void_function);
3659       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3660       break;
3661     }
3662 
3663     /*
3664     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3665     **
3666     ** Set the PENDING byte to the value in the argument, if X>0.
3667     ** Make no changes if X==0.  Return the value of the pending byte
3668     ** as it existing before this routine was called.
3669     **
3670     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3671     ** an incompatible database file format.  Changing the PENDING byte
3672     ** while any database connection is open results in undefined and
3673     ** deleterious behavior.
3674     */
3675     case SQLITE_TESTCTRL_PENDING_BYTE: {
3676       rc = PENDING_BYTE;
3677 #ifndef SQLITE_OMIT_WSD
3678       {
3679         unsigned int newVal = va_arg(ap, unsigned int);
3680         if( newVal ) sqlite3PendingByte = newVal;
3681       }
3682 #endif
3683       break;
3684     }
3685 
3686     /*
3687     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3688     **
3689     ** This action provides a run-time test to see whether or not
3690     ** assert() was enabled at compile-time.  If X is true and assert()
3691     ** is enabled, then the return value is true.  If X is true and
3692     ** assert() is disabled, then the return value is zero.  If X is
3693     ** false and assert() is enabled, then the assertion fires and the
3694     ** process aborts.  If X is false and assert() is disabled, then the
3695     ** return value is zero.
3696     */
3697     case SQLITE_TESTCTRL_ASSERT: {
3698       volatile int x = 0;
3699       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3700       rc = x;
3701       break;
3702     }
3703 
3704 
3705     /*
3706     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3707     **
3708     ** This action provides a run-time test to see how the ALWAYS and
3709     ** NEVER macros were defined at compile-time.
3710     **
3711     ** The return value is ALWAYS(X).
3712     **
3713     ** The recommended test is X==2.  If the return value is 2, that means
3714     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3715     ** default setting.  If the return value is 1, then ALWAYS() is either
3716     ** hard-coded to true or else it asserts if its argument is false.
3717     ** The first behavior (hard-coded to true) is the case if
3718     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3719     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3720     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3721     **
3722     ** The run-time test procedure might look something like this:
3723     **
3724     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3725     **      // ALWAYS() and NEVER() are no-op pass-through macros
3726     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3727     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3728     **    }else{
3729     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3730     **    }
3731     */
3732     case SQLITE_TESTCTRL_ALWAYS: {
3733       int x = va_arg(ap,int);
3734       rc = ALWAYS(x);
3735       break;
3736     }
3737 
3738     /*
3739     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3740     **
3741     ** The integer returned reveals the byte-order of the computer on which
3742     ** SQLite is running:
3743     **
3744     **       1     big-endian,    determined at run-time
3745     **      10     little-endian, determined at run-time
3746     **  432101     big-endian,    determined at compile-time
3747     **  123410     little-endian, determined at compile-time
3748     */
3749     case SQLITE_TESTCTRL_BYTEORDER: {
3750       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3751       break;
3752     }
3753 
3754     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3755     **
3756     ** Set the nReserve size to N for the main database on the database
3757     ** connection db.
3758     */
3759     case SQLITE_TESTCTRL_RESERVE: {
3760       sqlite3 *db = va_arg(ap, sqlite3*);
3761       int x = va_arg(ap,int);
3762       sqlite3_mutex_enter(db->mutex);
3763       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3764       sqlite3_mutex_leave(db->mutex);
3765       break;
3766     }
3767 
3768     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3769     **
3770     ** Enable or disable various optimizations for testing purposes.  The
3771     ** argument N is a bitmask of optimizations to be disabled.  For normal
3772     ** operation N should be 0.  The idea is that a test program (like the
3773     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3774     ** with various optimizations disabled to verify that the same answer
3775     ** is obtained in every case.
3776     */
3777     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3778       sqlite3 *db = va_arg(ap, sqlite3*);
3779       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3780       break;
3781     }
3782 
3783 #ifdef SQLITE_N_KEYWORD
3784     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3785     **
3786     ** If zWord is a keyword recognized by the parser, then return the
3787     ** number of keywords.  Or if zWord is not a keyword, return 0.
3788     **
3789     ** This test feature is only available in the amalgamation since
3790     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3791     ** is built using separate source files.
3792     */
3793     case SQLITE_TESTCTRL_ISKEYWORD: {
3794       const char *zWord = va_arg(ap, const char*);
3795       int n = sqlite3Strlen30(zWord);
3796       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3797       break;
3798     }
3799 #endif
3800 
3801     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3802     **
3803     ** Pass pFree into sqlite3ScratchFree().
3804     ** If sz>0 then allocate a scratch buffer into pNew.
3805     */
3806     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3807       void *pFree, **ppNew;
3808       int sz;
3809       sz = va_arg(ap, int);
3810       ppNew = va_arg(ap, void**);
3811       pFree = va_arg(ap, void*);
3812       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3813       sqlite3ScratchFree(pFree);
3814       break;
3815     }
3816 
3817     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3818     **
3819     ** If parameter onoff is non-zero, configure the wrappers so that all
3820     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3821     ** undo this setting.
3822     */
3823     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3824       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3825       break;
3826     }
3827 
3828     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3829     **
3830     ** Set or clear a flag that indicates that the database file is always well-
3831     ** formed and never corrupt.  This flag is clear by default, indicating that
3832     ** database files might have arbitrary corruption.  Setting the flag during
3833     ** testing causes certain assert() statements in the code to be activated
3834     ** that demonstrat invariants on well-formed database files.
3835     */
3836     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3837       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3838       break;
3839     }
3840 
3841     /* Set the threshold at which OP_Once counters reset back to zero.
3842     ** By default this is 0x7ffffffe (over 2 billion), but that value is
3843     ** too big to test in a reasonable amount of time, so this control is
3844     ** provided to set a small and easily reachable reset value.
3845     */
3846     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
3847       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
3848       break;
3849     }
3850 
3851     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3852     **
3853     ** Set the VDBE coverage callback function to xCallback with context
3854     ** pointer ptr.
3855     */
3856     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3857 #ifdef SQLITE_VDBE_COVERAGE
3858       typedef void (*branch_callback)(void*,int,u8,u8);
3859       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3860       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3861 #endif
3862       break;
3863     }
3864 
3865     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3866     case SQLITE_TESTCTRL_SORTER_MMAP: {
3867       sqlite3 *db = va_arg(ap, sqlite3*);
3868       db->nMaxSorterMmap = va_arg(ap, int);
3869       break;
3870     }
3871 
3872     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3873     **
3874     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3875     ** not.
3876     */
3877     case SQLITE_TESTCTRL_ISINIT: {
3878       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3879       break;
3880     }
3881 
3882     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3883     **
3884     ** This test control is used to create imposter tables.  "db" is a pointer
3885     ** to the database connection.  dbName is the database name (ex: "main" or
3886     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3887     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3888     ** table should connect.
3889     **
3890     ** Enable imposter mode only when the schema has already been parsed.  Then
3891     ** run a single CREATE TABLE statement to construct the imposter table in
3892     ** the parsed schema.  Then turn imposter mode back off again.
3893     **
3894     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3895     ** the schema to be reparsed the next time it is needed.  This has the
3896     ** effect of erasing all imposter tables.
3897     */
3898     case SQLITE_TESTCTRL_IMPOSTER: {
3899       sqlite3 *db = va_arg(ap, sqlite3*);
3900       sqlite3_mutex_enter(db->mutex);
3901       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3902       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3903       db->init.newTnum = va_arg(ap,int);
3904       if( db->init.busy==0 && db->init.newTnum>0 ){
3905         sqlite3ResetAllSchemasOfConnection(db);
3906       }
3907       sqlite3_mutex_leave(db->mutex);
3908       break;
3909     }
3910   }
3911   va_end(ap);
3912 #endif /* SQLITE_UNTESTABLE */
3913   return rc;
3914 }
3915 
3916 /*
3917 ** This is a utility routine, useful to VFS implementations, that checks
3918 ** to see if a database file was a URI that contained a specific query
3919 ** parameter, and if so obtains the value of the query parameter.
3920 **
3921 ** The zFilename argument is the filename pointer passed into the xOpen()
3922 ** method of a VFS implementation.  The zParam argument is the name of the
3923 ** query parameter we seek.  This routine returns the value of the zParam
3924 ** parameter if it exists.  If the parameter does not exist, this routine
3925 ** returns a NULL pointer.
3926 */
3927 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3928   if( zFilename==0 || zParam==0 ) return 0;
3929   zFilename += sqlite3Strlen30(zFilename) + 1;
3930   while( zFilename[0] ){
3931     int x = strcmp(zFilename, zParam);
3932     zFilename += sqlite3Strlen30(zFilename) + 1;
3933     if( x==0 ) return zFilename;
3934     zFilename += sqlite3Strlen30(zFilename) + 1;
3935   }
3936   return 0;
3937 }
3938 
3939 /*
3940 ** Return a boolean value for a query parameter.
3941 */
3942 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3943   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3944   bDflt = bDflt!=0;
3945   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3946 }
3947 
3948 /*
3949 ** Return a 64-bit integer value for a query parameter.
3950 */
3951 sqlite3_int64 sqlite3_uri_int64(
3952   const char *zFilename,    /* Filename as passed to xOpen */
3953   const char *zParam,       /* URI parameter sought */
3954   sqlite3_int64 bDflt       /* return if parameter is missing */
3955 ){
3956   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3957   sqlite3_int64 v;
3958   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3959     bDflt = v;
3960   }
3961   return bDflt;
3962 }
3963 
3964 /*
3965 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3966 */
3967 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3968   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
3969   return iDb<0 ? 0 : db->aDb[iDb].pBt;
3970 }
3971 
3972 /*
3973 ** Return the filename of the database associated with a database
3974 ** connection.
3975 */
3976 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3977   Btree *pBt;
3978 #ifdef SQLITE_ENABLE_API_ARMOR
3979   if( !sqlite3SafetyCheckOk(db) ){
3980     (void)SQLITE_MISUSE_BKPT;
3981     return 0;
3982   }
3983 #endif
3984   pBt = sqlite3DbNameToBtree(db, zDbName);
3985   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3986 }
3987 
3988 /*
3989 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3990 ** no such database exists.
3991 */
3992 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3993   Btree *pBt;
3994 #ifdef SQLITE_ENABLE_API_ARMOR
3995   if( !sqlite3SafetyCheckOk(db) ){
3996     (void)SQLITE_MISUSE_BKPT;
3997     return -1;
3998   }
3999 #endif
4000   pBt = sqlite3DbNameToBtree(db, zDbName);
4001   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
4002 }
4003 
4004 #ifdef SQLITE_ENABLE_SNAPSHOT
4005 /*
4006 ** Obtain a snapshot handle for the snapshot of database zDb currently
4007 ** being read by handle db.
4008 */
4009 int sqlite3_snapshot_get(
4010   sqlite3 *db,
4011   const char *zDb,
4012   sqlite3_snapshot **ppSnapshot
4013 ){
4014   int rc = SQLITE_ERROR;
4015 #ifndef SQLITE_OMIT_WAL
4016 
4017 #ifdef SQLITE_ENABLE_API_ARMOR
4018   if( !sqlite3SafetyCheckOk(db) ){
4019     return SQLITE_MISUSE_BKPT;
4020   }
4021 #endif
4022   sqlite3_mutex_enter(db->mutex);
4023 
4024   if( db->autoCommit==0 ){
4025     int iDb = sqlite3FindDbName(db, zDb);
4026     if( iDb==0 || iDb>1 ){
4027       Btree *pBt = db->aDb[iDb].pBt;
4028       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4029         rc = sqlite3BtreeBeginTrans(pBt, 0);
4030         if( rc==SQLITE_OK ){
4031           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4032         }
4033       }
4034     }
4035   }
4036 
4037   sqlite3_mutex_leave(db->mutex);
4038 #endif   /* SQLITE_OMIT_WAL */
4039   return rc;
4040 }
4041 
4042 /*
4043 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4044 */
4045 int sqlite3_snapshot_open(
4046   sqlite3 *db,
4047   const char *zDb,
4048   sqlite3_snapshot *pSnapshot
4049 ){
4050   int rc = SQLITE_ERROR;
4051 #ifndef SQLITE_OMIT_WAL
4052 
4053 #ifdef SQLITE_ENABLE_API_ARMOR
4054   if( !sqlite3SafetyCheckOk(db) ){
4055     return SQLITE_MISUSE_BKPT;
4056   }
4057 #endif
4058   sqlite3_mutex_enter(db->mutex);
4059   if( db->autoCommit==0 ){
4060     int iDb;
4061     iDb = sqlite3FindDbName(db, zDb);
4062     if( iDb==0 || iDb>1 ){
4063       Btree *pBt = db->aDb[iDb].pBt;
4064       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4065         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
4066         if( rc==SQLITE_OK ){
4067           rc = sqlite3BtreeBeginTrans(pBt, 0);
4068           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
4069         }
4070       }
4071     }
4072   }
4073 
4074   sqlite3_mutex_leave(db->mutex);
4075 #endif   /* SQLITE_OMIT_WAL */
4076   return rc;
4077 }
4078 
4079 /*
4080 ** Recover as many snapshots as possible from the wal file associated with
4081 ** schema zDb of database db.
4082 */
4083 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4084   int rc = SQLITE_ERROR;
4085   int iDb;
4086 #ifndef SQLITE_OMIT_WAL
4087 
4088 #ifdef SQLITE_ENABLE_API_ARMOR
4089   if( !sqlite3SafetyCheckOk(db) ){
4090     return SQLITE_MISUSE_BKPT;
4091   }
4092 #endif
4093 
4094   sqlite3_mutex_enter(db->mutex);
4095   iDb = sqlite3FindDbName(db, zDb);
4096   if( iDb==0 || iDb>1 ){
4097     Btree *pBt = db->aDb[iDb].pBt;
4098     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4099       rc = sqlite3BtreeBeginTrans(pBt, 0);
4100       if( rc==SQLITE_OK ){
4101         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4102         sqlite3BtreeCommit(pBt);
4103       }
4104     }
4105   }
4106   sqlite3_mutex_leave(db->mutex);
4107 #endif   /* SQLITE_OMIT_WAL */
4108   return rc;
4109 }
4110 
4111 /*
4112 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4113 */
4114 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4115   sqlite3_free(pSnapshot);
4116 }
4117 #endif /* SQLITE_ENABLE_SNAPSHOT */
4118 
4119 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4120 /*
4121 ** Given the name of a compile-time option, return true if that option
4122 ** was used and false if not.
4123 **
4124 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4125 ** is not required for a match.
4126 */
4127 int sqlite3_compileoption_used(const char *zOptName){
4128   int i, n;
4129   int nOpt;
4130   const char **azCompileOpt;
4131 
4132 #if SQLITE_ENABLE_API_ARMOR
4133   if( zOptName==0 ){
4134     (void)SQLITE_MISUSE_BKPT;
4135     return 0;
4136   }
4137 #endif
4138 
4139   azCompileOpt = sqlite3CompileOptions(&nOpt);
4140 
4141   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4142   n = sqlite3Strlen30(zOptName);
4143 
4144   /* Since nOpt is normally in single digits, a linear search is
4145   ** adequate. No need for a binary search. */
4146   for(i=0; i<nOpt; i++){
4147     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4148      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4149     ){
4150       return 1;
4151     }
4152   }
4153   return 0;
4154 }
4155 
4156 /*
4157 ** Return the N-th compile-time option string.  If N is out of range,
4158 ** return a NULL pointer.
4159 */
4160 const char *sqlite3_compileoption_get(int N){
4161   int nOpt;
4162   const char **azCompileOpt;
4163   azCompileOpt = sqlite3CompileOptions(&nOpt);
4164   if( N>=0 && N<nOpt ){
4165     return azCompileOpt[N];
4166   }
4167   return 0;
4168 }
4169 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4170