michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef prmon_h___
michael@0: #define prmon_h___
michael@0: 
michael@0: #include "prtypes.h"
michael@0: #include "prinrval.h"
michael@0: 
michael@0: PR_BEGIN_EXTERN_C
michael@0: 
michael@0: typedef struct PRMonitor PRMonitor;
michael@0: 
michael@0: /*
michael@0: ** Create a new monitor. Monitors are re-entrant locks with a single built-in
michael@0: ** condition variable.
michael@0: **
michael@0: ** This may fail if memory is tight or if some operating system resource
michael@0: ** is low.
michael@0: */
michael@0: NSPR_API(PRMonitor*) PR_NewMonitor(void);
michael@0: 
michael@0: /*
michael@0: ** Destroy a monitor. The caller is responsible for guaranteeing that the
michael@0: ** monitor is no longer in use. There must be no thread waiting on the monitor's
michael@0: ** condition variable and that the lock is not held.
michael@0: **
michael@0: */
michael@0: NSPR_API(void) PR_DestroyMonitor(PRMonitor *mon);
michael@0: 
michael@0: /*
michael@0: ** Enter the lock associated with the monitor. If the calling thread currently
michael@0: ** is in the monitor, the call to enter will silently succeed. In either case,
michael@0: ** it will increment the entry count by one.
michael@0: */
michael@0: NSPR_API(void) PR_EnterMonitor(PRMonitor *mon);
michael@0: 
michael@0: /*
michael@0: ** Decrement the entry count associated with the monitor. If the decremented
michael@0: ** entry count is zero, the monitor is exited. Returns PR_FAILURE if the
michael@0: ** calling thread has not entered the monitor.
michael@0: */
michael@0: NSPR_API(PRStatus) PR_ExitMonitor(PRMonitor *mon);
michael@0: 
michael@0: /*
michael@0: ** Wait for a notify on the monitor's condition variable. Sleep for "ticks"
michael@0: ** amount of time (if "ticks" is PR_INTERVAL_NO_TIMEOUT then the sleep is
michael@0: ** indefinite).
michael@0: **
michael@0: ** While the thread is waiting it exits the monitor (as if it called
michael@0: ** PR_ExitMonitor as many times as it had called PR_EnterMonitor).  When
michael@0: ** the wait has finished the thread regains control of the monitors lock
michael@0: ** with the same entry count as before the wait began.
michael@0: **
michael@0: ** The thread waiting on the monitor will be resumed when the monitor is
michael@0: ** notified (assuming the thread is the next in line to receive the
michael@0: ** notify) or when the "ticks" timeout elapses.
michael@0: **
michael@0: ** Returns PR_FAILURE if the caller has not entered the monitor.
michael@0: */
michael@0: NSPR_API(PRStatus) PR_Wait(PRMonitor *mon, PRIntervalTime ticks);
michael@0: 
michael@0: /*
michael@0: ** Notify a thread waiting on the monitor's condition variable. If a thread
michael@0: ** is waiting on the condition variable (using PR_Wait) then it is awakened
michael@0: ** and attempts to reenter the monitor.
michael@0: */
michael@0: NSPR_API(PRStatus) PR_Notify(PRMonitor *mon);
michael@0: 
michael@0: /*
michael@0: ** Notify all of the threads waiting on the monitor's condition variable.
michael@0: ** All of threads waiting on the condition are scheduled to reenter the
michael@0: ** monitor.
michael@0: */
michael@0: NSPR_API(PRStatus) PR_NotifyAll(PRMonitor *mon);
michael@0: 
michael@0: /*
michael@0: ** PR_ASSERT_CURRENT_THREAD_IN_MONITOR
michael@0: ** If the current thread is in |mon|, this assertion is guaranteed to
michael@0: ** succeed.  Otherwise, the behavior of this function is undefined.
michael@0: */
michael@0: #if defined(DEBUG) || defined(FORCE_PR_ASSERT)
michael@0: #define PR_ASSERT_CURRENT_THREAD_IN_MONITOR(/* PRMonitor* */ mon) \
michael@0:     PR_AssertCurrentThreadInMonitor(mon)
michael@0: #else
michael@0: #define PR_ASSERT_CURRENT_THREAD_IN_MONITOR(/* PRMonitor* */ mon)
michael@0: #endif
michael@0: 
michael@0: /* Don't call this function directly. */
michael@0: NSPR_API(void) PR_AssertCurrentThreadInMonitor(PRMonitor *mon);
michael@0: 
michael@0: PR_END_EXTERN_C
michael@0: 
michael@0: #endif /* prmon_h___ */