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Annotation of embedaddon/sqlite3/src/fault.c, revision 1.1.1.1

1.1       misho       1: /*
                      2: ** 2008 Jan 22
                      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: **
                     13: ** This file contains code to support the concept of "benign" 
                     14: ** malloc failures (when the xMalloc() or xRealloc() method of the
                     15: ** sqlite3_mem_methods structure fails to allocate a block of memory
                     16: ** and returns 0). 
                     17: **
                     18: ** Most malloc failures are non-benign. After they occur, SQLite
                     19: ** abandons the current operation and returns an error code (usually
                     20: ** SQLITE_NOMEM) to the user. However, sometimes a fault is not necessarily
                     21: ** fatal. For example, if a malloc fails while resizing a hash table, this 
                     22: ** is completely recoverable simply by not carrying out the resize. The 
                     23: ** hash table will continue to function normally.  So a malloc failure 
                     24: ** during a hash table resize is a benign fault.
                     25: */
                     26: 
                     27: #include "sqliteInt.h"
                     28: 
                     29: #ifndef SQLITE_OMIT_BUILTIN_TEST
                     30: 
                     31: /*
                     32: ** Global variables.
                     33: */
                     34: typedef struct BenignMallocHooks BenignMallocHooks;
                     35: static SQLITE_WSD struct BenignMallocHooks {
                     36:   void (*xBenignBegin)(void);
                     37:   void (*xBenignEnd)(void);
                     38: } sqlite3Hooks = { 0, 0 };
                     39: 
                     40: /* The "wsdHooks" macro will resolve to the appropriate BenignMallocHooks
                     41: ** structure.  If writable static data is unsupported on the target,
                     42: ** we have to locate the state vector at run-time.  In the more common
                     43: ** case where writable static data is supported, wsdHooks can refer directly
                     44: ** to the "sqlite3Hooks" state vector declared above.
                     45: */
                     46: #ifdef SQLITE_OMIT_WSD
                     47: # define wsdHooksInit \
                     48:   BenignMallocHooks *x = &GLOBAL(BenignMallocHooks,sqlite3Hooks)
                     49: # define wsdHooks x[0]
                     50: #else
                     51: # define wsdHooksInit
                     52: # define wsdHooks sqlite3Hooks
                     53: #endif
                     54: 
                     55: 
                     56: /*
                     57: ** Register hooks to call when sqlite3BeginBenignMalloc() and
                     58: ** sqlite3EndBenignMalloc() are called, respectively.
                     59: */
                     60: void sqlite3BenignMallocHooks(
                     61:   void (*xBenignBegin)(void),
                     62:   void (*xBenignEnd)(void)
                     63: ){
                     64:   wsdHooksInit;
                     65:   wsdHooks.xBenignBegin = xBenignBegin;
                     66:   wsdHooks.xBenignEnd = xBenignEnd;
                     67: }
                     68: 
                     69: /*
                     70: ** This (sqlite3EndBenignMalloc()) is called by SQLite code to indicate that
                     71: ** subsequent malloc failures are benign. A call to sqlite3EndBenignMalloc()
                     72: ** indicates that subsequent malloc failures are non-benign.
                     73: */
                     74: void sqlite3BeginBenignMalloc(void){
                     75:   wsdHooksInit;
                     76:   if( wsdHooks.xBenignBegin ){
                     77:     wsdHooks.xBenignBegin();
                     78:   }
                     79: }
                     80: void sqlite3EndBenignMalloc(void){
                     81:   wsdHooksInit;
                     82:   if( wsdHooks.xBenignEnd ){
                     83:     wsdHooks.xBenignEnd();
                     84:   }
                     85: }
                     86: 
                     87: #endif   /* #ifndef SQLITE_OMIT_BUILTIN_TEST */