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thread_pth.h
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177 lines (144 loc) · 4.59 KB
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/* GNU pth threads interface
http://www.gnu.org/software/pth
2000-05-03 Andy Dustman <andy@dustman.net>
Adapted from Posix threads interface
12 May 1997 -- david arnold <davida@pobox.com>
*/
#include <stdlib.h>
#include <string.h>
#include <pth.h>
/* A pth mutex isn't sufficient to model the Python lock type
* because pth mutexes can be acquired multiple times by the
* same thread.
*
* The pth_lock struct implements a Python lock as a "locked?" bit
* and a <condition, mutex> pair. In general, if the bit can be acquired
* instantly, it is, else the pair is used to block the thread until the
* bit is cleared.
*/
typedef struct {
char locked; /* 0=unlocked, 1=locked */
/* a <cond, mutex> pair to handle an acquire of a locked lock */
pth_cond_t lock_released;
pth_mutex_t mut;
} pth_lock;
#define CHECK_STATUS(name) if (status == -1) { printf("%d ", status); perror(name); error = 1; }
pth_attr_t PyThread_attr;
/*
* Initialization.
*/
static void PyThread__init_thread(void)
{
pth_init();
PyThread_attr = pth_attr_new();
pth_attr_set(PyThread_attr, PTH_ATTR_STACK_SIZE, 1<<18);
pth_attr_set(PyThread_attr, PTH_ATTR_JOINABLE, FALSE);
}
/*
* Thread support.
*/
long PyThread_start_new_thread(void (*func)(void *), void *arg)
{
pth_t th;
dprintf(("PyThread_start_new_thread called\n"));
if (!initialized)
PyThread_init_thread();
th = pth_spawn(PyThread_attr,
(void* (*)(void *))func,
(void *)arg
);
return th;
}
long PyThread_get_thread_ident(void)
{
volatile pth_t threadid;
if (!initialized)
PyThread_init_thread();
threadid = pth_self();
return (long) threadid;
}
void PyThread_exit_thread(void)
{
dprintf(("PyThread_exit_thread called\n"));
if (!initialized) {
exit(0);
}
}
/*
* Lock support.
*/
PyThread_type_lock PyThread_allocate_lock(void)
{
pth_lock *lock;
int status, error = 0;
dprintf(("PyThread_allocate_lock called\n"));
if (!initialized)
PyThread_init_thread();
lock = (pth_lock *) malloc(sizeof(pth_lock));
memset((void *)lock, '\0', sizeof(pth_lock));
if (lock) {
lock->locked = 0;
status = pth_mutex_init(&lock->mut);
CHECK_STATUS("pth_mutex_init");
status = pth_cond_init(&lock->lock_released);
CHECK_STATUS("pth_cond_init");
if (error) {
free((void *)lock);
lock = NULL;
}
}
dprintf(("PyThread_allocate_lock() -> %p\n", lock));
return (PyThread_type_lock) lock;
}
void PyThread_free_lock(PyThread_type_lock lock)
{
pth_lock *thelock = (pth_lock *)lock;
dprintf(("PyThread_free_lock(%p) called\n", lock));
free((void *)thelock);
}
int PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
{
int success;
pth_lock *thelock = (pth_lock *)lock;
int status, error = 0;
dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag));
status = pth_mutex_acquire(&thelock->mut, !waitflag, NULL);
CHECK_STATUS("pth_mutex_acquire[1]");
success = thelock->locked == 0;
if (success) thelock->locked = 1;
status = pth_mutex_release( &thelock->mut );
CHECK_STATUS("pth_mutex_release[1]");
if ( !success && waitflag ) {
/* continue trying until we get the lock */
/* mut must be locked by me -- part of the condition
* protocol */
status = pth_mutex_acquire( &thelock->mut, !waitflag, NULL );
CHECK_STATUS("pth_mutex_acquire[2]");
while ( thelock->locked ) {
status = pth_cond_await(&thelock->lock_released,
&thelock->mut, NULL);
CHECK_STATUS("pth_cond_await");
}
thelock->locked = 1;
status = pth_mutex_release( &thelock->mut );
CHECK_STATUS("pth_mutex_release[2]");
success = 1;
}
if (error) success = 0;
dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, success));
return success;
}
void PyThread_release_lock(PyThread_type_lock lock)
{
pth_lock *thelock = (pth_lock *)lock;
int status, error = 0;
dprintf(("PyThread_release_lock(%p) called\n", lock));
status = pth_mutex_acquire( &thelock->mut, 0, NULL );
CHECK_STATUS("pth_mutex_acquire[3]");
thelock->locked = 0;
status = pth_mutex_release( &thelock->mut );
CHECK_STATUS("pth_mutex_release[3]");
/* wake up someone (anyone, if any) waiting on the lock */
status = pth_cond_notify( &thelock->lock_released, 0 );
CHECK_STATUS("pth_cond_notify");
}