michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
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 vm_Monitor_h
michael@0: #define vm_Monitor_h
michael@0: 
michael@0: #ifdef JS_THREADSAFE
michael@0: #include "mozilla/DebugOnly.h"
michael@0: #endif
michael@0: 
michael@0: #include <stddef.h>
michael@0: 
michael@0: #include "jslock.h"
michael@0: 
michael@0: #include "js/Utility.h"
michael@0: 
michael@0: namespace js {
michael@0: 
michael@0: // A base class used for types intended to be used in a parallel
michael@0: // fashion, such as the workers in the |ThreadPool| class.  Combines a
michael@0: // lock and a condition variable.  You can acquire the lock or signal
michael@0: // the condition variable using the |AutoLockMonitor| type.
michael@0: 
michael@0: class Monitor
michael@0: {
michael@0:   protected:
michael@0:     friend class AutoLockMonitor;
michael@0:     friend class AutoUnlockMonitor;
michael@0: 
michael@0:     PRLock *lock_;
michael@0:     PRCondVar *condVar_;
michael@0: 
michael@0:   public:
michael@0:     Monitor()
michael@0:       : lock_(nullptr),
michael@0:         condVar_(nullptr)
michael@0:     { }
michael@0: 
michael@0:     ~Monitor() {
michael@0: #ifdef JS_THREADSAFE
michael@0:         if (lock_)
michael@0:             PR_DestroyLock(lock_);
michael@0:         if (condVar_)
michael@0:             PR_DestroyCondVar(condVar_);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     bool init();
michael@0: };
michael@0: 
michael@0: class AutoLockMonitor
michael@0: {
michael@0:   private:
michael@0: #ifdef JS_THREADSAFE
michael@0:     Monitor &monitor;
michael@0: #endif
michael@0: 
michael@0:   public:
michael@0:     AutoLockMonitor(Monitor &monitor)
michael@0: #ifdef JS_THREADSAFE
michael@0:       : monitor(monitor)
michael@0:     {
michael@0:         PR_Lock(monitor.lock_);
michael@0:     }
michael@0: #else
michael@0:     {}
michael@0: #endif
michael@0: 
michael@0:     ~AutoLockMonitor() {
michael@0: #ifdef JS_THREADSAFE
michael@0:         PR_Unlock(monitor.lock_);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     bool isFor(Monitor &other) const {
michael@0: #ifdef JS_THREADSAFE
michael@0:         return monitor.lock_ == other.lock_;
michael@0: #else
michael@0:         return true;
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     void wait(PRCondVar *condVar) {
michael@0: #ifdef JS_THREADSAFE
michael@0:         mozilla::DebugOnly<PRStatus> status =
michael@0:           PR_WaitCondVar(condVar, PR_INTERVAL_NO_TIMEOUT);
michael@0:         MOZ_ASSERT(status == PR_SUCCESS);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     void wait() {
michael@0: #ifdef JS_THREADSAFE
michael@0:         wait(monitor.condVar_);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     void notify(PRCondVar *condVar) {
michael@0: #ifdef JS_THREADSAFE
michael@0:         mozilla::DebugOnly<PRStatus> status = PR_NotifyCondVar(condVar);
michael@0:         MOZ_ASSERT(status == PR_SUCCESS);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     void notify() {
michael@0: #ifdef JS_THREADSAFE
michael@0:         notify(monitor.condVar_);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     void notifyAll(PRCondVar *condVar) {
michael@0: #ifdef JS_THREADSAFE
michael@0:         mozilla::DebugOnly<PRStatus> status = PR_NotifyAllCondVar(monitor.condVar_);
michael@0:         MOZ_ASSERT(status == PR_SUCCESS);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     void notifyAll() {
michael@0: #ifdef JS_THREADSAFE
michael@0:         notifyAll(monitor.condVar_);
michael@0: #endif
michael@0:     }
michael@0: };
michael@0: 
michael@0: class AutoUnlockMonitor
michael@0: {
michael@0:   private:
michael@0: #ifdef JS_THREADSAFE
michael@0:     Monitor &monitor;
michael@0: #endif
michael@0: 
michael@0:   public:
michael@0:     AutoUnlockMonitor(Monitor &monitor)
michael@0: #ifdef JS_THREADSAFE
michael@0:       : monitor(monitor)
michael@0:     {
michael@0:         PR_Unlock(monitor.lock_);
michael@0:     }
michael@0: #else
michael@0:     {}
michael@0: #endif
michael@0: 
michael@0:     ~AutoUnlockMonitor() {
michael@0: #ifdef JS_THREADSAFE
michael@0:         PR_Lock(monitor.lock_);
michael@0: #endif
michael@0:     }
michael@0: 
michael@0:     bool isFor(Monitor &other) const {
michael@0: #ifdef JS_THREADSAFE
michael@0:         return monitor.lock_ == other.lock_;
michael@0: #else
michael@0:         return true;
michael@0: #endif
michael@0:     }
michael@0: };
michael@0: 
michael@0: } // namespace js
michael@0: 
michael@0: #endif /* vm_Monitor_h */