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