ref: 5513dae7d9eee46f7e1843c8eeeaf9066d0ec632
dir: /sys/src/cmd/python/Python/thread_beos.h/
#include <kernel/OS.h>
#include <support/SupportDefs.h>
#include <errno.h>
/* ----------------------------------------------------------------------
* Fast locking mechanism described by Benoit Schillings (benoit@be.com)
* in the Be Developer's Newsletter, Issue #26 (http://www.be.com/).
*/
typedef struct benaphore {
sem_id _sem;
int32 _atom;
} benaphore_t;
static status_t benaphore_create( const char *name, benaphore_t *ben );
static status_t benaphore_destroy( benaphore_t *ben );
static status_t benaphore_lock( benaphore_t *ben );
static status_t benaphore_timedlock( benaphore_t *ben, bigtime_t micros );
static status_t benaphore_unlock( benaphore_t *ben );
static status_t benaphore_create( const char *name, benaphore_t *ben )
{
if( ben != NULL ) {
ben->_atom = 0;
ben->_sem = create_sem( 0, name );
if( ben->_sem < B_NO_ERROR ) {
return B_BAD_SEM_ID;
}
} else {
return EFAULT;
}
return EOK;
}
static status_t benaphore_destroy( benaphore_t *ben )
{
if( ben->_sem >= B_NO_ERROR ) {
status_t retval = benaphore_timedlock( ben, 0 );
if( retval == EOK || retval == EWOULDBLOCK ) {
status_t del_retval = delete_sem( ben->_sem );
return del_retval;
}
}
return B_BAD_SEM_ID;
}
static status_t benaphore_lock( benaphore_t *ben )
{
int32 prev = atomic_add( &(ben->_atom), 1 );
if( prev > 0 ) {
return acquire_sem( ben->_sem );
}
return EOK;
}
static status_t benaphore_timedlock( benaphore_t *ben, bigtime_t micros )
{
int32 prev = atomic_add( &(ben->_atom), 1 );
if( prev > 0 ) {
status_t retval = acquire_sem_etc( ben->_sem, 1, B_TIMEOUT, micros );
switch( retval ) {
case B_WOULD_BLOCK: /* Fall through... */
case B_TIMED_OUT:
return EWOULDBLOCK;
break;
case B_OK:
return EOK;
break;
default:
return retval;
break;
}
}
return EOK;
}
static status_t benaphore_unlock( benaphore_t *ben )
{
int32 prev = atomic_add( &(ben->_atom), -1 );
if( prev > 1 ) {
return release_sem( ben->_sem );
}
return EOK;
}
/* ----------------------------------------------------------------------
* Initialization.
*/
static void PyThread__init_thread( void )
{
/* Do nothing. */
return;
}
/* ----------------------------------------------------------------------
* Thread support.
*
* Only ANSI C, renamed functions here; you can't use K&R on BeOS,
* and there's no legacy thread module to support.
*/
static int32 thread_count = 0;
long PyThread_start_new_thread( void (*func)(void *), void *arg )
{
status_t success = 0;
thread_id tid;
char name[B_OS_NAME_LENGTH];
int32 this_thread;
dprintf(("PyThread_start_new_thread called\n"));
/* We are so very thread-safe... */
this_thread = atomic_add( &thread_count, 1 );
PyOS_snprintf(name, sizeof(name),
"python thread (%d)", this_thread );
tid = spawn_thread( (thread_func)func, name,
B_NORMAL_PRIORITY, arg );
if( tid > B_NO_ERROR ) {
success = resume_thread( tid );
}
return ( success == B_NO_ERROR ? tid : -1 );
}
long PyThread_get_thread_ident( void )
{
/* Presumed to return the current thread's ID... */
thread_id tid;
tid = find_thread( NULL );
return ( tid != B_NAME_NOT_FOUND ? tid : -1 );
}
static void do_PyThread_exit_thread( int no_cleanup )
{
int32 threads;
dprintf(("PyThread_exit_thread called\n"));
/* Thread-safe way to read a variable without a mutex: */
threads = atomic_add( &thread_count, 0 );
if( threads == 0 ) {
/* No threads around, so exit main(). */
if( no_cleanup ) {
_exit(0);
} else {
exit(0);
}
} else {
/* Oh, we're a thread, let's try to exit gracefully... */
exit_thread( B_NO_ERROR );
}
}
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));
/* No need to do anything, the threads get torn down if main() exits. */
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.
*/
static int32 lock_count = 0;
PyThread_type_lock PyThread_allocate_lock( void )
{
benaphore_t *lock;
status_t retval;
char name[B_OS_NAME_LENGTH];
int32 this_lock;
dprintf(("PyThread_allocate_lock called\n"));
lock = (benaphore_t *)malloc( sizeof( benaphore_t ) );
if( lock == NULL ) {
/* TODO: that's bad, raise MemoryError */
return (PyThread_type_lock)NULL;
}
this_lock = atomic_add( &lock_count, 1 );
PyOS_snprintf(name, sizeof(name), "python lock (%d)", this_lock);
retval = benaphore_create( name, lock );
if( retval != EOK ) {
/* TODO: that's bad, raise an exception */
return (PyThread_type_lock)NULL;
}
dprintf(("PyThread_allocate_lock() -> %p\n", lock));
return (PyThread_type_lock) lock;
}
void PyThread_free_lock( PyThread_type_lock lock )
{
status_t retval;
dprintf(("PyThread_free_lock(%p) called\n", lock));
retval = benaphore_destroy( (benaphore_t *)lock );
if( retval != EOK ) {
/* TODO: that's bad, raise an exception */
return;
}
}
int PyThread_acquire_lock( PyThread_type_lock lock, int waitflag )
{
int success;
status_t retval;
dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag));
if( waitflag ) {
retval = benaphore_lock( (benaphore_t *)lock );
} else {
retval = benaphore_timedlock( (benaphore_t *)lock, 0 );
}
if( retval == EOK ) {
success = 1;
} else {
success = 0;
/* TODO: that's bad, raise an exception */
}
dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, success));
return success;
}
void PyThread_release_lock( PyThread_type_lock lock )
{
status_t retval;
dprintf(("PyThread_release_lock(%p) called\n", lock));
retval = benaphore_unlock( (benaphore_t *)lock );
if( retval != EOK ) {
/* TODO: that's bad, raise an exception */
return;
}
}