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