ref: 36af8405521be371605e4658ec8f4b133f3c7d6f
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 ([email protected]) * 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; } }