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SF patch #474500: Make OS/2 locks work like posix locks, from Michael

Browse source 
Muller.
This commit is contained in:
Tim Peters 2001-10-31 03:50:45 +00:00
parent 7e0f81e631
commit a6ca4f40d0
2 changed files with 63 additions and 31 deletions
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1
Misc/ACKS
View file

@ -297,6 +297,7 @@ The Dragon De Monsyne
Skip Montanaro
Sape Mullender
Sjoerd Mullender
Michael Muller
Takahiro Nakayama
Travers Naran
Fredrik Nehr

93
Python/thread_os2.h
View file

@ -101,82 +101,113 @@ PyThread__exit_prog(int status)
#endif /* NO_EXIT_PROG */
/*
* Lock support. It has too be implemented as semaphores.
* I [Dag] tried to implement it with mutex but I could find a way to
* tell whether a thread already own the lock or not.
* Lock support. This is implemented with an event semaphore and critical
* sections to make it behave more like a posix mutex than its OS/2
# counterparts.
*/
typedef struct os2_lock_t {
int is_set;
HEV changed;
} *type_os2_lock;
PyThread_type_lock
PyThread_allocate_lock(void)
{
HMTX aLock;
APIRET rc;
type_os2_lock lock = (type_os2_lock)malloc(sizeof(struct os2_lock_t));
dprintf(("PyThread_allocate_lock called\n"));
if (!initialized)
PyThread_init_thread();
DosCreateMutexSem(NULL, /* Sem name */
&aLock, /* the semaphore */
0, /* shared ? */
0); /* initial state */
lock->is_set = 0;
dprintf(("%ld: PyThread_allocate_lock() -> %p\n", PyThread_get_thread_ident(), aLock));
DosCreateEventSem(NULL, &lock->changed, 0, 0);
return (PyThread_type_lock) aLock;
dprintf(("%ld: PyThread_allocate_lock() -> %p\n",
PyThread_get_thread_ident(),
lock->changed));
return (PyThread_type_lock) lock;
}
void
PyThread_free_lock(PyThread_type_lock aLock)
{
type_os2_lock lock = (type_os2_lock)aLock;
dprintf(("%ld: PyThread_free_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
DosCloseMutexSem((HMTX)aLock);
DosCloseEventSem(lock->changed);
free(aLock);
}
/*
* Return 1 on success if the lock was acquired
*
* and 0 if the lock was not acquired. This means a 0 is returned
* if the lock has already been acquired by this thread!
* and 0 if the lock was not acquired.
*/
int
PyThread_acquire_lock(PyThread_type_lock aLock, int waitflag)
{
int success = 1;
ULONG rc, count;
int done = 0;
ULONG count;
PID pid = 0;
TID tid = 0;
type_os2_lock lock = (type_os2_lock)aLock;
dprintf(("%ld: PyThread_acquire_lock(%p, %d) called\n", PyThread_get_thread_ident(),
aLock, waitflag));
DosQueryMutexSem((HMTX)aLock,&pid,&tid,&count);
if( tid == PyThread_get_thread_ident() ) { /* if we own this lock */
success = 0;
} else {
rc = DosRequestMutexSem((HMTX) aLock,
(waitflag == 1 ? SEM_INDEFINITE_WAIT : 0));
if( rc != 0) {
success = 0; /* We failed */
while (!done) {
/* if the lock is currently set, we have to wait for the state to change */
if (lock->is_set) {
if (!waitflag)
return 0;
DosWaitEventSem(lock->changed, SEM_INDEFINITE_WAIT);
}
/*
* enter a critical section and try to get the semaphore. If
* it is still locked, we will try again.
*/
if (DosEnterCritSec())
return 0;
if (!lock->is_set) {
lock->is_set = 1;
DosResetEventSem(lock->changed, &count);
done = 1;
}
DosExitCritSec();
}
dprintf(("%ld: PyThread_acquire_lock(%p, %d) -> %d\n",
PyThread_get_thread_ident(),aLock, waitflag, success));
return success;
return 1;
}
void
PyThread_release_lock(PyThread_type_lock aLock)
void PyThread_release_lock(PyThread_type_lock aLock)
{
type_os2_lock lock = (type_os2_lock)aLock;
dprintf(("%ld: PyThread_release_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
if ( DosReleaseMutexSem( (HMTX) aLock ) != 0 ) {
if (!lock->is_set) {
dprintf(("%ld: Could not PyThread_release_lock(%p) error: %l\n",
PyThread_get_thread_ident(), aLock, GetLastError()));
return;
}
if (DosEnterCritSec()) {
dprintf(("%ld: Could not PyThread_release_lock(%p) error: %l\n",
PyThread_get_thread_ident(), aLock, GetLastError()));
return;
}
lock->is_set = 0;
DosPostEventSem(lock->changed);
DosExitCritSec();
}
/*