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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/. */

 #ifndef prmon_h___

 #define prmon_h___

 #include "prtypes.h"

 #include "prinrval.h"

 PR_BEGIN_EXTERN_C

 typedef struct PRMonitor PRMonitor;

 /*

 ** Create a new monitor. Monitors are re-entrant locks with a single built-in

 ** condition variable.

 **

 ** This may fail if memory is tight or if some operating system resource

 ** is low.

 */

 NSPR_API(PRMonitor*) PR_NewMonitor(void);

 /*

 ** Destroy a monitor. The caller is responsible for guaranteeing that the

 ** monitor is no longer in use. There must be no thread waiting on the monitor's

 ** condition variable and that the lock is not held.

 **

 */

 NSPR_API(void) PR_DestroyMonitor(PRMonitor *mon);

 /*

 ** Enter the lock associated with the monitor. If the calling thread currently

 ** is in the monitor, the call to enter will silently succeed. In either case,

 ** it will increment the entry count by one.

 */

 NSPR_API(void) PR_EnterMonitor(PRMonitor *mon);

 /*

 ** Decrement the entry count associated with the monitor. If the decremented

 ** entry count is zero, the monitor is exited. Returns PR_FAILURE if the

 ** calling thread has not entered the monitor.

 */

 NSPR_API(PRStatus) PR_ExitMonitor(PRMonitor *mon);

 /*

 ** Wait for a notify on the monitor's condition variable. Sleep for "ticks"

 ** amount of time (if "ticks" is PR_INTERVAL_NO_TIMEOUT then the sleep is

 ** indefinite).

 **

 ** While the thread is waiting it exits the monitor (as if it called

 ** PR_ExitMonitor as many times as it had called PR_EnterMonitor).  When

 ** the wait has finished the thread regains control of the monitors lock

 ** with the same entry count as before the wait began.

 **

 ** The thread waiting on the monitor will be resumed when the monitor is

 ** notified (assuming the thread is the next in line to receive the

 ** notify) or when the "ticks" timeout elapses.

 **

 ** Returns PR_FAILURE if the caller has not entered the monitor.

 */

 NSPR_API(PRStatus) PR_Wait(PRMonitor *mon, PRIntervalTime ticks);

 /*

 ** Notify a thread waiting on the monitor's condition variable. If a thread

 ** is waiting on the condition variable (using PR_Wait) then it is awakened

 ** and attempts to reenter the monitor.

 */

 NSPR_API(PRStatus) PR_Notify(PRMonitor *mon);

 /*

 ** Notify all of the threads waiting on the monitor's condition variable.

 ** All of threads waiting on the condition are scheduled to reenter the

 ** monitor.

 */

 NSPR_API(PRStatus) PR_NotifyAll(PRMonitor *mon);

 /*

 ** PR_ASSERT_CURRENT_THREAD_IN_MONITOR

 ** If the current thread is in |mon|, this assertion is guaranteed to

 ** succeed.  Otherwise, the behavior of this function is undefined.

 */

 #if defined(DEBUG) || defined(FORCE_PR_ASSERT)

 #define PR_ASSERT_CURRENT_THREAD_IN_MONITOR(/* PRMonitor* */ mon) \

     PR_AssertCurrentThreadInMonitor(mon)

 #else

 #define PR_ASSERT_CURRENT_THREAD_IN_MONITOR(/* PRMonitor* */ mon)

 #endif

 /* Don't call this function directly. */

 NSPR_API(void) PR_AssertCurrentThreadInMonitor(PRMonitor *mon);

 PR_END_EXTERN_C

 #endif /* prmon_h___ */