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			367 lines
		
	
	
	
		
			8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			367 lines
		
	
	
	
		
			8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/***********************************************************
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Copyright (c) 2000, BeOpen.com.
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Copyright (c) 1995-2000, Corporation for National Research Initiatives.
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Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
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All rights reserved.
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See the file "Misc/COPYRIGHT" for information on usage and
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redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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BeOS thread support by Chris Herborth (chrish@qnx.com)
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******************************************************************/
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#include <kernel/OS.h>
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#include <support/SupportDefs.h>
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#include <errno.h>
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/* ----------------------------------------------------------------------
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 * Fast locking mechanism described by Benoit Schillings (benoit@be.com)
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 * in the Be Developer's Newsletter, Issue #26 (http://www.be.com/).
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 */
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typedef struct benaphore {
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	sem_id _sem;
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	int32  _atom;
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} benaphore_t;
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static status_t benaphore_create( const char *name, benaphore_t *ben );
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static status_t benaphore_destroy( benaphore_t *ben );
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static status_t benaphore_lock( benaphore_t *ben );
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static status_t benaphore_timedlock( benaphore_t *ben, bigtime_t micros );
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static status_t benaphore_unlock( benaphore_t *ben );
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static status_t benaphore_create( const char *name, benaphore_t *ben )
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{
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	if( ben != NULL ) {
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		ben->_atom = 0;
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		ben->_sem = create_sem( 0, name );
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		if( ben->_sem < B_NO_ERROR ) {
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			return B_BAD_SEM_ID;
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		}
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	} else {
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		return EFAULT;
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	}
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	return EOK;
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}
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static status_t benaphore_destroy( benaphore_t *ben )
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{
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	if( ben->_sem >= B_NO_ERROR ) {
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		status_t retval = benaphore_timedlock( ben, 0 );
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		if( retval == EOK || retval == EWOULDBLOCK ) {
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			status_t del_retval = delete_sem( ben->_sem );
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			return del_retval;
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		}
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	}
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	return B_BAD_SEM_ID;
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}
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static status_t benaphore_lock( benaphore_t *ben )
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{
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	int32 prev = atomic_add( &(ben->_atom), 1 );
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	if( prev > 0 ) {
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		return acquire_sem( ben->_sem );
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	}
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	return EOK;
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}
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static status_t benaphore_timedlock( benaphore_t *ben, bigtime_t micros )
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{
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	int32 prev = atomic_add( &(ben->_atom), 1 );
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	if( prev > 0 ) {
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		status_t retval = acquire_sem_etc( ben->_sem, 1, B_TIMEOUT, micros );
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		switch( retval ) {
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		case B_WOULD_BLOCK:	/* Fall through... */
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		case B_TIMED_OUT:
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			return EWOULDBLOCK;
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			break;
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		case B_OK:
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			return EOK;
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			break;
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		default:
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			return retval;
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			break;
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		}
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	}
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	return EOK;
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}
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static status_t benaphore_unlock( benaphore_t *ben )
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{
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	int32 prev = atomic_add( &(ben->_atom), -1 );
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	if( prev > 1 ) {
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		return release_sem( ben->_sem );
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	}
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	return EOK;
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}
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/* ----------------------------------------------------------------------
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 * Initialization.
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 */
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static void PyThread__init_thread( void )
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{
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	/* Do nothing. */
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	return;
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}
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/* ----------------------------------------------------------------------
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 * Thread support.
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 *
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 * Only ANSI C, renamed functions here; you can't use K&R on BeOS,
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 * and there's no legacy thread module to support.
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 */
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static int32 thread_count = 0;
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int PyThread_start_new_thread( void (*func)(void *), void *arg )
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{
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	status_t success = 0;
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	thread_id tid;
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	char name[B_OS_NAME_LENGTH];
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	int32 this_thread;
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	dprintf(("PyThread_start_new_thread called\n"));
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	/* We are so very thread-safe... */
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	this_thread = atomic_add( &thread_count, 1 );
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	sprintf( name, "python thread (%d)", this_thread );
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	tid = spawn_thread( (thread_func)func, name,
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	                    B_NORMAL_PRIORITY, arg );
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	if( tid > B_NO_ERROR ) {
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		success = resume_thread( tid );
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	}
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	return ( success == B_NO_ERROR ? 1 : 0 );
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}
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long PyThread_get_thread_ident( void )
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{
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	/* Presumed to return the current thread's ID... */
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	thread_id tid;
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	tid = find_thread( NULL );
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	return ( tid != B_NAME_NOT_FOUND ? tid : -1 );
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}
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static void do_PyThread_exit_thread( int no_cleanup )
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{
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	int32 threads;
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	dprintf(("PyThread_exit_thread called\n"));
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	/* Thread-safe way to read a variable without a mutex: */
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	threads = atomic_add( &thread_count, 0 );
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	if( threads == 0 ) {
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		/* No threads around, so exit main(). */
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		if( no_cleanup ) {
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			_exit(0);
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		} else {
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			exit(0);
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		}
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	} else {
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		/* Oh, we're a thread, let's try to exit gracefully... */
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		exit_thread( B_NO_ERROR );
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	}
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}
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void PyThread_exit_thread( void )
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{
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	do_PyThread_exit_thread(0);
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}
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void PyThread__exit_thread( void )
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{
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	do_PyThread_exit_thread(1);
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}
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#ifndef NO_EXIT_PROG
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static void do_PyThread_exit_prog( int status, int no_cleanup )
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{
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	dprintf(("PyThread_exit_prog(%d) called\n", status));
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	/* No need to do anything, the threads get torn down if main() exits. */
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	if (no_cleanup) {
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		_exit(status);
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	} else {
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		exit(status);
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	}
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}
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void PyThread_exit_prog( int status )
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{
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	do_PyThread_exit_prog(status, 0);
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}
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void PyThread__exit_prog( int status )
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{
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	do_PyThread_exit_prog(status, 1);
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}
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#endif /* NO_EXIT_PROG */
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/* ----------------------------------------------------------------------
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 * Lock support.
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 */
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static int32 lock_count = 0;
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PyThread_type_lock PyThread_allocate_lock( void )
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{
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	benaphore_t *lock;
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	status_t retval;
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	char name[B_OS_NAME_LENGTH];
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	int32 this_lock;
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	dprintf(("PyThread_allocate_lock called\n"));
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	lock = (benaphore_t *)malloc( sizeof( benaphore_t ) );
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	if( lock == NULL ) {
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		/* TODO: that's bad, raise MemoryError */
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		return (PyThread_type_lock)NULL;
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	}
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	this_lock = atomic_add( &lock_count, 1 );
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	sprintf( name, "python lock (%d)", this_lock );
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	retval = benaphore_create( name, lock );
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	if( retval != EOK ) {
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		/* TODO: that's bad, raise an exception */
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		return (PyThread_type_lock)NULL;
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	}
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	dprintf(("PyThread_allocate_lock() -> %p\n", lock));
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	return (PyThread_type_lock) lock;
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}
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void PyThread_free_lock( PyThread_type_lock lock )
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{
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	status_t retval;
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	dprintf(("PyThread_free_lock(%p) called\n", lock));
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	retval = benaphore_destroy( (benaphore_t *)lock );
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	if( retval != EOK ) {
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		/* TODO: that's bad, raise an exception */
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		return;
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	}
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}
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int PyThread_acquire_lock( PyThread_type_lock lock, int waitflag )
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{
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	int success;
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	status_t retval;
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	dprintf(("PyThread_acquire_lock(%p, %d) called\n", lock, waitflag));
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	if( waitflag ) {
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		retval = benaphore_lock( (benaphore_t *)lock );
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	} else {
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		retval = benaphore_timedlock( (benaphore_t *)lock, 0 );
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	}
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	if( retval == EOK ) {
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		success = 1;
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	} else {
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		success = 0;
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		/* TODO: that's bad, raise an exception */
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	}
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	dprintf(("PyThread_acquire_lock(%p, %d) -> %d\n", lock, waitflag, success));
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	return success;
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}
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void PyThread_release_lock( PyThread_type_lock lock )
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{
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	status_t retval;
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	dprintf(("PyThread_release_lock(%p) called\n", lock));
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	retval = benaphore_unlock( (benaphore_t *)lock );
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	if( retval != EOK ) {
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		/* TODO: that's bad, raise an exception */
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		return;
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	}
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}
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/* ----------------------------------------------------------------------
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 * Semaphore support.
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 *
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 * Guido says not to implement this because it's not used anywhere;
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 * I'll do it anyway, you never know when it might be handy, and it's
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 * easy...
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 */
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PyThread_type_sema PyThread_allocate_sema( int value )
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{
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	sem_id sema;
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	dprintf(("PyThread_allocate_sema called\n"));
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	sema = create_sem( value, "python semaphore" );
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	if( sema < B_NO_ERROR ) {
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		/* TODO: that's bad, raise an exception */
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		return 0;
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	}
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	dprintf(("PyThread_allocate_sema() -> %p\n", sema));
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	return (PyThread_type_sema) sema;
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}
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void PyThread_free_sema( PyThread_type_sema sema )
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{
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	status_t retval;
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	dprintf(("PyThread_free_sema(%p) called\n", sema));
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	retval = delete_sem( (sem_id)sema );
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	if( retval != B_NO_ERROR ) {
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		/* TODO: that's bad, raise an exception */
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		return;
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	}
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}
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int PyThread_down_sema( PyThread_type_sema sema, int waitflag )
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{
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	status_t retval;
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	dprintf(("PyThread_down_sema(%p, %d) called\n", sema, waitflag));
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	if( waitflag ) {
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		retval = acquire_sem( (sem_id)sema );
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	} else {
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		retval = acquire_sem_etc( (sem_id)sema, 1, B_TIMEOUT, 0 );
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	}
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	if( retval != B_NO_ERROR ) {
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		/* TODO: that's bad, raise an exception */
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		return 0;
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	}
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	dprintf(("PyThread_down_sema(%p) return\n", sema));
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	return -1;
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}
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void PyThread_up_sema( PyThread_type_sema sema )
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{
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	status_t retval;
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	dprintf(("PyThread_up_sema(%p)\n", sema));
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	retval = release_sem( (sem_id)sema );
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	if( retval != B_NO_ERROR ) {
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		/* TODO: that's bad, raise an exception */
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		return;
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	}
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}
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