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nsprpub/pr/src/bthreads/btsem.c@6474c204b198 (annotated)

nsprpub/pr/src/bthreads/btsem.c

Wed, 31 Dec 2014 06:09:35 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Wed, 31 Dec 2014 06:09:35 +0100

changeset 0

6474c204b198

permissions

-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

michael@0	1	/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0	2	/* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	3	* License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0	4	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	5
michael@0	6	#include <kernel/OS.h>
michael@0	7
michael@0	8	#include "primpl.h"
michael@0	9
michael@0	10	/*
michael@0	11	** Create a new semaphore object.
michael@0	12	*/
michael@0	13	PR_IMPLEMENT(PRSemaphore*)
michael@0	14	PR_NewSem (PRUintn value)
michael@0	15	{
michael@0	16	PRSemaphore *semaphore;
michael@0	17
michael@0	18	if (!_pr_initialized) _PR_ImplicitInitialization();
michael@0	19
michael@0	20	semaphore = PR_NEWZAP(PRSemaphore);
michael@0	21	if (NULL != semaphore) {
michael@0	22	if ((semaphore->sem = create_sem(value, "nspr_sem")) < B_NO_ERROR)
michael@0	23	return NULL;
michael@0	24	else
michael@0	25	return semaphore;
michael@0	26	}
michael@0	27	return NULL;
michael@0	28	}
michael@0	29
michael@0	30	/*
michael@0	31	** Destroy the given semaphore object.
michael@0	32	**
michael@0	33	*/
michael@0	34	PR_IMPLEMENT(void)
michael@0	35	PR_DestroySem (PRSemaphore *sem)
michael@0	36	{
michael@0	37	status_t result;
michael@0	38
michael@0	39	PR_ASSERT(sem != NULL);
michael@0	40	result = delete_sem(sem->sem);
michael@0	41	PR_ASSERT(result == B_NO_ERROR);
michael@0	42	PR_DELETE(sem);
michael@0	43	}
michael@0	44
michael@0	45	/*
michael@0	46	** Wait on a Semaphore.
michael@0	47	**
michael@0	48	** This routine allows a calling thread to wait or proceed depending upon
michael@0	49	** the state of the semahore sem. The thread can proceed only if the
michael@0	50	** counter value of the semaphore sem is currently greater than 0. If the
michael@0	51	** value of semaphore sem is positive, it is decremented by one and the
michael@0	52	** routine returns immediately allowing the calling thread to continue. If
michael@0	53	** the value of semaphore sem is 0, the calling thread blocks awaiting the
michael@0	54	** semaphore to be released by another thread.
michael@0	55	**
michael@0	56	** This routine can return PR_PENDING_INTERRUPT if the waiting thread
michael@0	57	** has been interrupted.
michael@0	58	*/
michael@0	59	PR_IMPLEMENT(PRStatus)
michael@0	60	PR_WaitSem (PRSemaphore *sem)
michael@0	61	{
michael@0	62	PR_ASSERT(sem != NULL);
michael@0	63	if (acquire_sem(sem->sem) == B_NO_ERROR)
michael@0	64	return PR_SUCCESS;
michael@0	65	else
michael@0	66	return PR_FAILURE;
michael@0	67	}
michael@0	68
michael@0	69	/*
michael@0	70	** This routine increments the counter value of the semaphore. If other
michael@0	71	** threads are blocked for the semaphore, then the scheduler will
michael@0	72	** determine which ONE thread will be unblocked.
michael@0	73	*/
michael@0	74	PR_IMPLEMENT(void)
michael@0	75	PR_PostSem (PRSemaphore *sem)
michael@0	76	{
michael@0	77	status_t result;
michael@0	78
michael@0	79	PR_ASSERT(sem != NULL);
michael@0	80	result = release_sem_etc(sem->sem, 1, B_DO_NOT_RESCHEDULE);
michael@0	81	PR_ASSERT(result == B_NO_ERROR);
michael@0	82	}
michael@0	83
michael@0	84	/*
michael@0	85	** Returns the value of the semaphore referenced by sem without affecting
michael@0	86	** the state of the semaphore. The value represents the semaphore value
michael@0	87	** at the time of the call, but may not be the actual value when the
michael@0	88	** caller inspects it.
michael@0	89	*/
michael@0	90	PR_IMPLEMENT(PRUintn)
michael@0	91	PR_GetValueSem (PRSemaphore *sem)
michael@0	92	{
michael@0	93	sem_info info;
michael@0	94
michael@0	95	PR_ASSERT(sem != NULL);
michael@0	96	get_sem_info(sem->sem, &info);
michael@0	97	return info.count;
michael@0	98	}