/* 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();

	/* Jump through some hoops for Alpha OSF/1 */

	threadid = pth_self();

	return (long) *(long *) &threadid;

}

static void do_PyThread_exit_thread(int no_cleanup)

{

	dprintf(("PyThread_exit_thread called\n"));

	if (!initialized) {

		if (no_cleanup)

			_exit(0);

		else

			exit(0);

	}

}

void PyThread_exit_thread(void)

{

	do_PyThread_exit_thread(0);

}

void PyThread__exit_thread(void)

{

	do_PyThread_exit_thread(1);

}

#ifndef NO_EXIT_PROG

static void do_PyThread_exit_prog(int status, int no_cleanup)

{

	dprintf(("PyThread_exit_prog(%d) called\n", status));

	if (!initialized)

		if (no_cleanup)

			_exit(status);

		else

			exit(status);

}

void PyThread_exit_prog(int status)

{

	do_PyThread_exit_prog(status, 0);

}

void PyThread__exit_prog(int status)

{

	do_PyThread_exit_prog(status, 1);

}

#endif /* NO_EXIT_PROG */

/*

 * 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");

}