sl@0: /*
sl@0: ** 2008 Jan 22
sl@0: **
sl@0: ** The author disclaims copyright to this source code.  In place of
sl@0: ** a legal notice, here is a blessing:
sl@0: **
sl@0: **    May you do good and not evil.
sl@0: **    May you find forgiveness for yourself and forgive others.
sl@0: **    May you share freely, never taking more than you give.
sl@0: **
sl@0: *************************************************************************
sl@0: **
sl@0: ** $Id: fault.c,v 1.11 2008/09/02 00:52:52 drh Exp $
sl@0: */
sl@0: 
sl@0: /*
sl@0: ** This file contains code to support the concept of "benign" 
sl@0: ** malloc failures (when the xMalloc() or xRealloc() method of the
sl@0: ** sqlite3_mem_methods structure fails to allocate a block of memory
sl@0: ** and returns 0). 
sl@0: **
sl@0: ** Most malloc failures are non-benign. After they occur, SQLite
sl@0: ** abandons the current operation and returns an error code (usually
sl@0: ** SQLITE_NOMEM) to the user. However, sometimes a fault is not necessarily
sl@0: ** fatal. For example, if a malloc fails while resizing a hash table, this 
sl@0: ** is completely recoverable simply by not carrying out the resize. The 
sl@0: ** hash table will continue to function normally.  So a malloc failure 
sl@0: ** during a hash table resize is a benign fault.
sl@0: */
sl@0: 
sl@0: #include "sqliteInt.h"
sl@0: 
sl@0: #ifndef SQLITE_OMIT_BUILTIN_TEST
sl@0: 
sl@0: /*
sl@0: ** Global variables.
sl@0: */
sl@0: typedef struct BenignMallocHooks BenignMallocHooks;
sl@0: static SQLITE_WSD struct BenignMallocHooks {
sl@0:   void (*xBenignBegin)(void);
sl@0:   void (*xBenignEnd)(void);
sl@0: } sqlite3Hooks = { 0, 0 };
sl@0: 
sl@0: /* The "wsdHooks" macro will resolve to the appropriate BenignMallocHooks
sl@0: ** structure.  If writable static data is unsupported on the target,
sl@0: ** we have to locate the state vector at run-time.  In the more common
sl@0: ** case where writable static data is supported, wsdHooks can refer directly
sl@0: ** to the "sqlite3Hooks" state vector declared above.
sl@0: */
sl@0: #ifdef SQLITE_OMIT_WSD
sl@0: # define wsdHooksInit \
sl@0:   BenignMallocHooks *x = &GLOBAL(BenignMallocHooks,sqlite3Hooks)
sl@0: # define wsdHooks x[0]
sl@0: #else
sl@0: # define wsdHooksInit
sl@0: # define wsdHooks sqlite3Hooks
sl@0: #endif
sl@0: 
sl@0: 
sl@0: /*
sl@0: ** Register hooks to call when sqlite3BeginBenignMalloc() and
sl@0: ** sqlite3EndBenignMalloc() are called, respectively.
sl@0: */
sl@0: void sqlite3BenignMallocHooks(
sl@0:   void (*xBenignBegin)(void),
sl@0:   void (*xBenignEnd)(void)
sl@0: ){
sl@0:   wsdHooksInit;
sl@0:   wsdHooks.xBenignBegin = xBenignBegin;
sl@0:   wsdHooks.xBenignEnd = xBenignEnd;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** This (sqlite3EndBenignMalloc()) is called by SQLite code to indicate that
sl@0: ** subsequent malloc failures are benign. A call to sqlite3EndBenignMalloc()
sl@0: ** indicates that subsequent malloc failures are non-benign.
sl@0: */
sl@0: void sqlite3BeginBenignMalloc(void){
sl@0:   wsdHooksInit;
sl@0:   if( wsdHooks.xBenignBegin ){
sl@0:     wsdHooks.xBenignBegin();
sl@0:   }
sl@0: }
sl@0: void sqlite3EndBenignMalloc(void){
sl@0:   wsdHooksInit;
sl@0:   if( wsdHooks.xBenignEnd ){
sl@0:     wsdHooks.xBenignEnd();
sl@0:   }
sl@0: }
sl@0: 
sl@0: #endif   /* #ifndef SQLITE_OMIT_BUILTIN_TEST */