diff -r 87e863f6f840 -r 3903521a36da engine/sqlite/src/mutex.cpp --- a/engine/sqlite/src/mutex.cpp Wed May 26 10:44:32 2010 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,126 +0,0 @@ -/* -** 2007 August 14 -** -** The author disclaims copyright to this source code. In place of -** a legal notice, here is a blessing: -** -** May you do good and not evil. -** May you find forgiveness for yourself and forgive others. -** May you share freely, never taking more than you give. -** -************************************************************************* -** This file contains the C functions that implement mutexes. -** -** The implementation in this file does not provide any mutual -** exclusion and is thus suitable for use only in applications -** that use SQLite in a single thread. But this implementation -** does do a lot of error checking on mutexes to make sure they -** are called correctly and at appropriate times. Hence, this -** implementation is suitable for testing. -** debugging purposes -** -** $Id: mutex.cpp 1282 2008-11-13 09:31:33Z LarsPson $ -*/ -#include "sqliteInt.h" - -#ifdef SQLITE_MUTEX_NOOP_DEBUG -/* -** In this implementation, mutexes do not provide any mutual exclusion. -** But the error checking is provided. This implementation is useful -** for test purposes. -*/ - -/* -** The mutex object -*/ -struct sqlite3_mutex { - int id; /* The mutex type */ - int cnt; /* Number of entries without a matching leave */ -}; - -/* -** The sqlite3_mutex_alloc() routine allocates a new -** mutex and returns a pointer to it. If it returns NULL -** that means that a mutex could not be allocated. -*/ -sqlite3_mutex *sqlite3_mutex_alloc(int id){ - static sqlite3_mutex aStatic[5]; - sqlite3_mutex *pNew = 0; - switch( id ){ - case SQLITE_MUTEX_FAST: - case SQLITE_MUTEX_RECURSIVE: { - pNew = sqlite3_malloc(sizeof(*pNew)); - if( pNew ){ - pNew->id = id; - pNew->cnt = 0; - } - break; - } - default: { - assert( id-2 >= 0 ); - assert( id-2 < sizeof(aStatic)/sizeof(aStatic[0]) ); - pNew = &aStatic[id-2]; - pNew->id = id; - break; - } - } - return pNew; -} - -/* -** This routine deallocates a previously allocated mutex. -*/ -void sqlite3_mutex_free(sqlite3_mutex *p){ - assert( p ); - assert( p->cnt==0 ); - assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE ); - sqlite3_free(p); -} - -/* -** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt -** to enter a mutex. If another thread is already within the mutex, -** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return -** SQLITE_BUSY. The sqlite3_mutex_try() interface returns SQLITE_OK -** upon successful entry. Mutexes created using SQLITE_MUTEX_RECURSIVE can -** be entered multiple times by the same thread. In such cases the, -** mutex must be exited an equal number of times before another thread -** can enter. If the same thread tries to enter any other kind of mutex -** more than once, the behavior is undefined. -*/ -void sqlite3_mutex_enter(sqlite3_mutex *p){ - assert( p ); - assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); - p->cnt++; -} -int sqlite3_mutex_try(sqlite3_mutex *p){ - assert( p ); - assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); - p->cnt++; - return SQLITE_OK; -} - -/* -** The sqlite3_mutex_leave() routine exits a mutex that was -** previously entered by the same thread. The behavior -** is undefined if the mutex is not currently entered or -** is not currently allocated. SQLite will never do either. -*/ -void sqlite3_mutex_leave(sqlite3_mutex *p){ - assert( p ); - assert( sqlite3_mutex_held(p) ); - p->cnt--; - assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); -} - -/* -** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are -** intended for use inside assert() statements. -*/ -int sqlite3_mutex_held(sqlite3_mutex *p){ - return p==0 || p->cnt>0; -} -int sqlite3_mutex_notheld(sqlite3_mutex *p){ - return p==0 || p->cnt==0; -} -#endif /* SQLITE_MUTEX_NOOP_DEBUG */