summaryrefslogtreecommitdiffstats
path: root/nsprpub/pr/src/bthreads/btmon.c
diff options
context:
space:
mode:
authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /nsprpub/pr/src/bthreads/btmon.c
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
downloadUXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.gz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.lz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.tar.xz
UXP-5f8de423f190bbb79a62f804151bc24824fa32d8.zip
Add m-esr52 at 52.6.0
Diffstat (limited to 'nsprpub/pr/src/bthreads/btmon.c')
-rw-r--r--nsprpub/pr/src/bthreads/btmon.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/nsprpub/pr/src/bthreads/btmon.c b/nsprpub/pr/src/bthreads/btmon.c
new file mode 100644
index 000000000..bd05e73dc
--- /dev/null
+++ b/nsprpub/pr/src/bthreads/btmon.c
@@ -0,0 +1,201 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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/. */
+
+#include <kernel/OS.h>
+
+#include "primpl.h"
+
+/*
+** 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.
+*/
+PR_IMPLEMENT(PRMonitor*)
+ PR_NewMonitor (void)
+{
+ PRMonitor *mon;
+ PRCondVar *cvar;
+ PRLock *lock;
+
+ mon = PR_NEWZAP( PRMonitor );
+ if( mon )
+ {
+ lock = PR_NewLock();
+ if( !lock )
+ {
+ PR_DELETE( mon );
+ return( 0 );
+ }
+
+ cvar = PR_NewCondVar( lock );
+ if( !cvar )
+ {
+ PR_DestroyLock( lock );
+ PR_DELETE( mon );
+ return( 0 );
+ }
+
+ mon->cvar = cvar;
+ mon->name = NULL;
+ }
+
+ return( mon );
+}
+
+PR_IMPLEMENT(PRMonitor*) PR_NewNamedMonitor(const char* name)
+{
+ PRMonitor* mon = PR_NewMonitor();
+ if( mon )
+ {
+ mon->name = name;
+ }
+ return mon;
+}
+
+/*
+** 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.
+**
+*/
+PR_IMPLEMENT(void)
+ PR_DestroyMonitor (PRMonitor *mon)
+{
+ PR_DestroyLock( mon->cvar->lock );
+ PR_DestroyCondVar( mon->cvar );
+ PR_DELETE( 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.
+*/
+PR_IMPLEMENT(void)
+ PR_EnterMonitor (PRMonitor *mon)
+{
+ if( mon->cvar->lock->owner == find_thread( NULL ) )
+ {
+ mon->entryCount++;
+
+ } else
+ {
+ PR_Lock( mon->cvar->lock );
+ mon->entryCount = 1;
+ }
+}
+
+/*
+** 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.
+*/
+PR_IMPLEMENT(PRStatus)
+ PR_ExitMonitor (PRMonitor *mon)
+{
+ if( mon->cvar->lock->owner != find_thread( NULL ) )
+ {
+ return( PR_FAILURE );
+ }
+ if( --mon->entryCount == 0 )
+ {
+ return( PR_Unlock( mon->cvar->lock ) );
+ }
+ return( PR_SUCCESS );
+}
+
+/*
+** 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.
+*/
+PR_IMPLEMENT(PRStatus)
+ PR_Wait (PRMonitor *mon, PRIntervalTime ticks)
+{
+ PRUint32 entryCount;
+ PRUintn status;
+ PRThread *meThread;
+ thread_id me = find_thread( NULL );
+ meThread = PR_GetCurrentThread();
+
+ if( mon->cvar->lock->owner != me ) return( PR_FAILURE );
+
+ entryCount = mon->entryCount;
+ mon->entryCount = 0;
+
+ status = PR_WaitCondVar( mon->cvar, ticks );
+
+ mon->entryCount = entryCount;
+
+ return( status );
+}
+
+/*
+** 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.
+*/
+PR_IMPLEMENT(PRStatus)
+ PR_Notify (PRMonitor *mon)
+{
+ if( mon->cvar->lock->owner != find_thread( NULL ) )
+ {
+ return( PR_FAILURE );
+ }
+
+ PR_NotifyCondVar( mon->cvar );
+ return( PR_SUCCESS );
+}
+
+/*
+** 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.
+*/
+PR_IMPLEMENT(PRStatus)
+ PR_NotifyAll (PRMonitor *mon)
+{
+ if( mon->cvar->lock->owner != find_thread( NULL ) )
+ {
+ return( PR_FAILURE );
+ }
+
+ PR_NotifyAllCondVar( mon->cvar );
+ return( PR_SUCCESS );
+}
+
+/*
+** Return the number of times that the current thread has entered the
+** lock. Returns zero if the current thread has not entered the lock.
+*/
+PR_IMPLEMENT(PRIntn)
+ PR_GetMonitorEntryCount(PRMonitor *mon)
+{
+ return( (mon->cvar->lock->owner == find_thread( NULL )) ?
+ mon->entryCount : 0 );
+}
+
+/*
+** If the current thread is in |mon|, this assertion is guaranteed to
+** succeed. Otherwise, the behavior of this function is undefined.
+*/
+PR_IMPLEMENT(void)
+ PR_AssertCurrentThreadInMonitor(PRMonitor *mon)
+{
+ PR_ASSERT_CURRENT_THREAD_OWNS_LOCK(mon->cvar->lock);
+}