cpython/Python/thread_atheos.h at 2.7 · python-emscripten/cpython · GitHub

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/* Threading for AtheOS.

Based on thread_beos.h. */

#include <atheos/threads.h>

#include <atheos/semaphore.h>

#include <atheos/atomic.h>

#include <errno.h>

#include <string.h>

/* Missing decl from threads.h */

extern int exit_thread(int);

/* Undefine FASTLOCK to play with simple semaphores. */

#define FASTLOCK

#ifdef FASTLOCK

/* Use an atomic counter and a semaphore for maximum speed. */

typedef struct fastmutex {

sem_id sem;

atomic_t count;

} fastmutex_t;

static int fastmutex_create(const char *name, fastmutex_t * mutex);

static int fastmutex_destroy(fastmutex_t * mutex);

static int fastmutex_lock(fastmutex_t * mutex);

static int fastmutex_timedlock(fastmutex_t * mutex, bigtime_t timeout);

static int fastmutex_unlock(fastmutex_t * mutex);

static int fastmutex_create(const char *name, fastmutex_t * mutex)

{

mutex->count = 0;

mutex->sem = create_semaphore(name, 0, 0);

return (mutex->sem < 0) ? -1 : 0;

}

static int fastmutex_destroy(fastmutex_t * mutex)

{

if (fastmutex_timedlock(mutex, 0) == 0 || errno == EWOULDBLOCK) {

return delete_semaphore(mutex->sem);

}

return 0;

}

static int fastmutex_lock(fastmutex_t * mutex)

{

atomic_t prev = atomic_add(&mutex->count, 1);

if (prev > 0)

return lock_semaphore(mutex->sem);

return 0;

}

static int fastmutex_timedlock(fastmutex_t * mutex, bigtime_t timeout)

{

atomic_t prev = atomic_add(&mutex->count, 1);

if (prev > 0)

return lock_semaphore_x(mutex->sem, 1, 0, timeout);

return 0;

}

static int fastmutex_unlock(fastmutex_t * mutex)

{

atomic_t prev = atomic_add(&mutex->count, -1);

if (prev > 1)

return unlock_semaphore(mutex->sem);

return 0;

}

#endif /* FASTLOCK */

* Initialization.

static void PyThread__init_thread(void)

{

/* Do nothing. */

return;

}

* Thread support.

static atomic_t thread_count = 0;

long PyThread_start_new_thread(void (*func) (void *), void *arg)

{

status_t success = -1;

thread_id tid;

char name[OS_NAME_LENGTH];

atomic_t this_thread;

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

this_thread = atomic_add(&thread_count, 1);

PyOS_snprintf(name, sizeof(name), "python thread (%d)", this_thread);

tid = spawn_thread(name, func, NORMAL_PRIORITY, 0, arg);

if (tid < 0) {

dprintf(("PyThread_start_new_thread spawn_thread failed: %s\n", strerror(errno)));

} else {

success = resume_thread(tid);

if (success < 0) {

dprintf(("PyThread_start_new_thread resume_thread failed: %s\n", strerror(errno)));

}

return (success < 0 ? -1 : tid);

}

long PyThread_get_thread_ident(void)

{

return get_thread_id(NULL);

}

void PyThread_exit_thread(void)

{

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

/* Thread-safe way to read a variable without a mutex: */

if (atomic_add(&thread_count, 0) == 0) {

/* No threads around, so exit main(). */

exit(0);

} else {

/* We're a thread */

exit_thread(0);

}

* Lock support.

static atomic_t lock_count = 0;

PyThread_type_lock PyThread_allocate_lock(void)

{

#ifdef FASTLOCK

fastmutex_t *lock;

#else

sem_id sema;

#endif

char name[OS_NAME_LENGTH];

atomic_t this_lock;

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

#ifdef FASTLOCK

lock = (fastmutex_t *) malloc(sizeof(fastmutex_t));

if (lock == NULL) {

dprintf(("PyThread_allocate_lock failed: out of memory\n"));

return (PyThread_type_lock) NULL;

}

#endif

this_lock = atomic_add(&lock_count, 1);

PyOS_snprintf(name, sizeof(name), "python lock (%d)", this_lock);

#ifdef FASTLOCK

if (fastmutex_create(name, lock) < 0) {

dprintf(("PyThread_allocate_lock failed: %s\n",

strerror(errno)));

free(lock);

lock = NULL;

}

dprintf(("PyThread_allocate_lock()-> %p\n", lock));

return (PyThread_type_lock) lock;

#else

sema = create_semaphore(name, 1, 0);

if (sema < 0) {

dprintf(("PyThread_allocate_lock failed: %s\n",

strerror(errno)));

sema = 0;

}

dprintf(("PyThread_allocate_lock()-> %p\n", sema));

return (PyThread_type_lock) sema;

#endif

}

void PyThread_free_lock(PyThread_type_lock lock)

{

dprintf(("PyThread_free_lock(%p) called\n", lock));

#ifdef FASTLOCK

if (fastmutex_destroy((fastmutex_t *) lock) < 0) {

dprintf(("PyThread_free_lock(%p) failed: %s\n", lock,

strerror(errno)));

}

free(lock);

#else

if (delete_semaphore((sem_id) lock) < 0) {

dprintf(("PyThread_free_lock(%p) failed: %s\n", lock,

strerror(errno)));

}

#endif

}

int PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)

{

int retval;

dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock,

waitflag));

#ifdef FASTLOCK

if (waitflag)

retval = fastmutex_lock((fastmutex_t *) lock);

else

retval = fastmutex_timedlock((fastmutex_t *) lock, 0);

#else

if (waitflag)

retval = lock_semaphore((sem_id) lock);

else

retval = lock_semaphore_x((sem_id) lock, 1, 0, 0);

#endif

if (retval < 0) {

dprintf(("PyThread_acquire_lock(%p, %d) failed: %s\n",

lock, waitflag, strerror(errno)));

}

dprintf(("PyThread_acquire_lock(%p, %d)-> %d\n", lock, waitflag,

retval));

return retval < 0 ? 0 : 1;

}

void PyThread_release_lock(PyThread_type_lock lock)

{

dprintf(("PyThread_release_lock(%p) called\n", lock));

#ifdef FASTLOCK

if (fastmutex_unlock((fastmutex_t *) lock) < 0) {

dprintf(("PyThread_release_lock(%p) failed: %s\n", lock,

strerror(errno)));

}

#else

if (unlock_semaphore((sem_id) lock) < 0) {

dprintf(("PyThread_release_lock(%p) failed: %s\n", lock,

strerror(errno)));

}

#endif

}

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