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110 lines
3.7 KiB
C
110 lines
3.7 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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** File: prlock.h
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** Description: API to basic locking functions of NSPR.
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**
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**
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** NSPR provides basic locking mechanisms for thread synchronization. Locks
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** are lightweight resource contention controls that prevent multiple threads
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** from accessing something (code/data) simultaneously.
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**/
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#ifndef prlock_h___
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#define prlock_h___
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#include "prtypes.h"
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PR_BEGIN_EXTERN_C
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/**********************************************************************/
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/************************* TYPES AND CONSTANTS ************************/
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/**********************************************************************/
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/*
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* PRLock --
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*
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* NSPR represents the lock as an opaque entity to the client of the
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* API. All routines operate on a pointer to this opaque entity.
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*/
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typedef struct PRLock PRLock;
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/**********************************************************************/
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/****************************** FUNCTIONS *****************************/
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/**********************************************************************/
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/***********************************************************************
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** FUNCTION: PR_NewLock
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** DESCRIPTION:
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** Returns a pointer to a newly created opaque lock object.
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** INPUTS: void
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** OUTPUTS: void
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** RETURN: PRLock*
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** If the lock can not be created because of resource constraints, NULL
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** is returned.
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**
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***********************************************************************/
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NSPR_API(PRLock*) PR_NewLock(void);
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/***********************************************************************
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** FUNCTION: PR_DestroyLock
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** DESCRIPTION:
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** Destroys a given opaque lock object.
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** INPUTS: PRLock *lock
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** Lock to be freed.
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** OUTPUTS: void
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** RETURN: None
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***********************************************************************/
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NSPR_API(void) PR_DestroyLock(PRLock *lock);
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/***********************************************************************
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** FUNCTION: PR_Lock
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** DESCRIPTION:
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** Lock a lock.
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** INPUTS: PRLock *lock
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** Lock to locked.
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** OUTPUTS: void
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** RETURN: None
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***********************************************************************/
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NSPR_API(void) PR_Lock(PRLock *lock);
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/***********************************************************************
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** FUNCTION: PR_Unlock
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** DESCRIPTION:
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** Unlock a lock. Unlocking an unlocked lock has undefined results.
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** INPUTS: PRLock *lock
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** Lock to unlocked.
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** OUTPUTS: void
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** RETURN: PR_STATUS
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** Returns PR_FAILURE if the caller does not own the lock.
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***********************************************************************/
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NSPR_API(PRStatus) PR_Unlock(PRLock *lock);
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/***********************************************************************
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** MACRO: PR_ASSERT_CURRENT_THREAD_OWNS_LOCK
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** DESCRIPTION:
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** If the current thread owns |lock|, this assertion is guaranteed to
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** succeed. Otherwise, the behavior of this function is undefined.
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** INPUTS: PRLock *lock
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** Lock to assert ownership of.
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** OUTPUTS: void
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** RETURN: None
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***********************************************************************/
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#if defined(DEBUG) || defined(FORCE_PR_ASSERT)
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#define PR_ASSERT_CURRENT_THREAD_OWNS_LOCK(/* PrLock* */ lock) \
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PR_AssertCurrentThreadOwnsLock(lock)
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#else
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#define PR_ASSERT_CURRENT_THREAD_OWNS_LOCK(/* PrLock* */ lock)
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#endif
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/* Don't call this function directly. */
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NSPR_API(void) PR_AssertCurrentThreadOwnsLock(PRLock *lock);
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PR_END_EXTERN_C
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#endif /* prlock_h___ */
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