diff -r 000000000000 -r bde4ae8d615e os/persistentdata/persistentstorage/sqlite3api/SQLite/mutex_os2.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/os/persistentdata/persistentstorage/sqlite3api/SQLite/mutex_os2.c Fri Jun 15 03:10:57 2012 +0200 @@ -0,0 +1,273 @@ +/* +** 2007 August 28 +** +** 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 for OS/2 +** +** $Id: mutex_os2.c,v 1.10 2008/06/23 22:13:28 pweilbacher Exp $ +*/ +#include "sqliteInt.h" + +/* +** The code in this file is only used if SQLITE_MUTEX_OS2 is defined. +** See the mutex.h file for details. +*/ +#ifdef SQLITE_MUTEX_OS2 + +/********************** OS/2 Mutex Implementation ********************** +** +** This implementation of mutexes is built using the OS/2 API. +*/ + +/* +** The mutex object +** Each recursive mutex is an instance of the following structure. +*/ +struct sqlite3_mutex { + HMTX mutex; /* Mutex controlling the lock */ + int id; /* Mutex type */ + int nRef; /* Number of references */ + TID owner; /* Thread holding this mutex */ +}; + +#define OS2_MUTEX_INITIALIZER 0,0,0,0 + +/* +** Initialize and deinitialize the mutex subsystem. +*/ +static int os2MutexInit(void){ return SQLITE_OK; } +static int os2MutexEnd(void){ return SQLITE_OK; } + +/* +** 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. +** SQLite will unwind its stack and return an error. The argument +** to sqlite3_mutex_alloc() is one of these integer constants: +** +** +** +** The first two constants cause sqlite3_mutex_alloc() to create +** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE +** is used but not necessarily so when SQLITE_MUTEX_FAST is used. +** The mutex implementation does not need to make a distinction +** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does +** not want to. But SQLite will only request a recursive mutex in +** cases where it really needs one. If a faster non-recursive mutex +** implementation is available on the host platform, the mutex subsystem +** might return such a mutex in response to SQLITE_MUTEX_FAST. +** +** The other allowed parameters to sqlite3_mutex_alloc() each return +** a pointer to a static preexisting mutex. Three static mutexes are +** used by the current version of SQLite. Future versions of SQLite +** may add additional static mutexes. Static mutexes are for internal +** use by SQLite only. Applications that use SQLite mutexes should +** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or +** SQLITE_MUTEX_RECURSIVE. +** +** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST +** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() +** returns a different mutex on every call. But for the static +** mutex types, the same mutex is returned on every call that has +** the same type number. +*/ +static sqlite3_mutex *os2MutexAlloc(int iType){ + sqlite3_mutex *p = NULL; + switch( iType ){ + case SQLITE_MUTEX_FAST: + case SQLITE_MUTEX_RECURSIVE: { + p = sqlite3MallocZero( sizeof(*p) ); + if( p ){ + p->id = iType; + if( DosCreateMutexSem( 0, &p->mutex, 0, FALSE ) != NO_ERROR ){ + sqlite3_free( p ); + p = NULL; + } + } + break; + } + default: { + static volatile int isInit = 0; + static sqlite3_mutex staticMutexes[] = { + { OS2_MUTEX_INITIALIZER, }, + { OS2_MUTEX_INITIALIZER, }, + { OS2_MUTEX_INITIALIZER, }, + { OS2_MUTEX_INITIALIZER, }, + { OS2_MUTEX_INITIALIZER, }, + { OS2_MUTEX_INITIALIZER, }, + }; + if ( !isInit ){ + APIRET rc; + PTIB ptib; + PPIB ppib; + HMTX mutex; + char name[32]; + DosGetInfoBlocks( &ptib, &ppib ); + sqlite3_snprintf( sizeof(name), name, "\\SEM32\\SQLITE%04x", + ppib->pib_ulpid ); + while( !isInit ){ + mutex = 0; + rc = DosCreateMutexSem( name, &mutex, 0, FALSE); + if( rc == NO_ERROR ){ + int i; + if( !isInit ){ + for( i = 0; i < sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++ ){ + DosCreateMutexSem( 0, &staticMutexes[i].mutex, 0, FALSE ); + } + isInit = 1; + } + DosCloseMutexSem( mutex ); + }else if( rc == ERROR_DUPLICATE_NAME ){ + DosSleep( 1 ); + }else{ + return p; + } + } + } + assert( iType-2 >= 0 ); + assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) ); + p = &staticMutexes[iType-2]; + p->id = iType; + break; + } + } + return p; +} + + +/* +** This routine deallocates a previously allocated mutex. +** SQLite is careful to deallocate every mutex that it allocates. +*/ +static void os2MutexFree(sqlite3_mutex *p){ + if( p==0 ) return; + assert( p->nRef==0 ); + assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE ); + DosCloseMutexSem( p->mutex ); + 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. +*/ +static void os2MutexEnter(sqlite3_mutex *p){ + TID tid; + PID holder1; + ULONG holder2; + if( p==0 ) return; + assert( p->id==SQLITE_MUTEX_RECURSIVE || os2MutexNotheld(p) ); + DosRequestMutexSem(p->mutex, SEM_INDEFINITE_WAIT); + DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2); + p->owner = tid; + p->nRef++; +} +static int os2MutexTry(sqlite3_mutex *p){ + int rc; + TID tid; + PID holder1; + ULONG holder2; + if( p==0 ) return SQLITE_OK; + assert( p->id==SQLITE_MUTEX_RECURSIVE || os2MutexNotheld(p) ); + if( DosRequestMutexSem(p->mutex, SEM_IMMEDIATE_RETURN) == NO_ERROR) { + DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2); + p->owner = tid; + p->nRef++; + rc = SQLITE_OK; + } else { + rc = SQLITE_BUSY; + } + + return rc; +} + +/* +** 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. +*/ +static void os2MutexLeave(sqlite3_mutex *p){ + TID tid; + PID holder1; + ULONG holder2; + if( p==0 ) return; + assert( p->nRef>0 ); + DosQueryMutexSem(p->mutex, &holder1, &tid, &holder2); + assert( p->owner==tid ); + p->nRef--; + assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE ); + DosReleaseMutexSem(p->mutex); +} + +#ifdef SQLITE_DEBUG +/* +** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are +** intended for use inside assert() statements. +*/ +static int os2MutexHeld(sqlite3_mutex *p){ + TID tid; + PID pid; + ULONG ulCount; + PTIB ptib; + if( p!=0 ) { + DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount); + } else { + DosGetInfoBlocks(&ptib, NULL); + tid = ptib->tib_ptib2->tib2_ultid; + } + return p==0 || (p->nRef!=0 && p->owner==tid); +} +static int os2MutexNotheld(sqlite3_mutex *p){ + TID tid; + PID pid; + ULONG ulCount; + PTIB ptib; + if( p!= 0 ) { + DosQueryMutexSem(p->mutex, &pid, &tid, &ulCount); + } else { + DosGetInfoBlocks(&ptib, NULL); + tid = ptib->tib_ptib2->tib2_ultid; + } + return p==0 || p->nRef==0 || p->owner!=tid; +} +#endif + +sqlite3_mutex_methods *sqlite3DefaultMutex(void){ + static sqlite3_mutex_methods sMutex = { + os2MutexInit, + os2MutexEnd, + os2MutexAlloc, + os2MutexFree, + os2MutexEnter, + os2MutexTry, + os2MutexLeave, +#ifdef SQLITE_DEBUG + os2MutexHeld, + os2MutexNotheld +#endif + }; + + return &sMutex; +} +#endif /* SQLITE_MUTEX_OS2 */