1 files changed, 135 insertions, 0 deletions
diff --git a/xpcom/glue/Monitor.h b/xpcom/glue/Monitor.h
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+++ b/xpcom/glue/Monitor.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 mozilla_Monitor_h
+#define mozilla_Monitor_h
+
+#include "mozilla/CondVar.h"
+#include "mozilla/Mutex.h"
+
+namespace mozilla {
+
+/**
+ * Monitor provides a *non*-reentrant monitor: *not* a Java-style
+ * monitor.  If your code needs support for reentrancy, use
+ * ReentrantMonitor instead.  (Rarely should reentrancy be needed.)
+ *
+ * Instead of directly calling Monitor methods, it's safer and simpler
+ * to instead use the RAII wrappers MonitorAutoLock and
+ * MonitorAutoUnlock.
+ */
+class Monitor
+{
+public:
+  explicit Monitor(const char* aName)
+    : mMutex(aName)
+    , mCondVar(mMutex, "[Monitor.mCondVar]")
+  {
+  }
+
+  ~Monitor() {}
+
+  void Lock() { mMutex.Lock(); }
+  void Unlock() { mMutex.Unlock(); }
+
+  nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT)
+  {
+    return mCondVar.Wait(aInterval);
+  }
+
+  nsresult Notify() { return mCondVar.Notify(); }
+  nsresult NotifyAll() { return mCondVar.NotifyAll(); }
+
+  void AssertCurrentThreadOwns() const
+  {
+    mMutex.AssertCurrentThreadOwns();
+  }
+
+  void AssertNotCurrentThreadOwns() const
+  {
+    mMutex.AssertNotCurrentThreadOwns();
+  }
+
+private:
+  Monitor();
+  Monitor(const Monitor&);
+  Monitor& operator=(const Monitor&);
+
+  Mutex mMutex;
+  CondVar mCondVar;
+};
+
+/**
+ * Lock the monitor for the lexical scope instances of this class are
+ * bound to (except for MonitorAutoUnlock in nested scopes).
+ *
+ * The monitor must be unlocked when instances of this class are
+ * created.
+ */
+class MOZ_STACK_CLASS MonitorAutoLock
+{
+public:
+  explicit MonitorAutoLock(Monitor& aMonitor)
+    : mMonitor(&aMonitor)
+  {
+    mMonitor->Lock();
+  }
+
+  ~MonitorAutoLock()
+  {
+    mMonitor->Unlock();
+  }
+
+  nsresult Wait(PRIntervalTime aInterval = PR_INTERVAL_NO_TIMEOUT)
+  {
+    return mMonitor->Wait(aInterval);
+  }
+
+  nsresult Notify() { return mMonitor->Notify(); }
+  nsresult NotifyAll() { return mMonitor->NotifyAll(); }
+
+private:
+  MonitorAutoLock();
+  MonitorAutoLock(const MonitorAutoLock&);
+  MonitorAutoLock& operator=(const MonitorAutoLock&);
+  static void* operator new(size_t) CPP_THROW_NEW;
+
+  Monitor* mMonitor;
+};
+
+/**
+ * Unlock the monitor for the lexical scope instances of this class
+ * are bound to (except for MonitorAutoLock in nested scopes).
+ *
+ * The monitor must be locked by the current thread when instances of
+ * this class are created.
+ */
+class MOZ_STACK_CLASS MonitorAutoUnlock
+{
+public:
+  explicit MonitorAutoUnlock(Monitor& aMonitor)
+    : mMonitor(&aMonitor)
+  {
+    mMonitor->Unlock();
+  }
+
+  ~MonitorAutoUnlock()
+  {
+    mMonitor->Lock();
+  }
+
+private:
+  MonitorAutoUnlock();
+  MonitorAutoUnlock(const MonitorAutoUnlock&);
+  MonitorAutoUnlock& operator=(const MonitorAutoUnlock&);
+  static void* operator new(size_t) CPP_THROW_NEW;
+
+  Monitor* mMonitor;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_Monitor_h