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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_Mutex_h
+#define mozilla_Mutex_h
+
+#include "prlock.h"
+
+#include "mozilla/BlockingResourceBase.h"
+#include "mozilla/GuardObjects.h"
+
+//
+// Provides:
+//
+// - Mutex, a non-recursive mutex
+// - MutexAutoLock, an RAII class for ensuring that Mutexes are properly
+// locked and unlocked
+// - MutexAutoUnlock, complementary sibling to MutexAutoLock
+//
+// - OffTheBooksMutex, a non-recursive mutex that doesn't do leak checking
+// - OffTheBooksMutexAuto{Lock,Unlock} - Like MutexAuto{Lock,Unlock}, but for
+// an OffTheBooksMutex.
+//
+// Using MutexAutoLock/MutexAutoUnlock etc. is MUCH preferred to making bare
+// calls to Lock and Unlock.
+//
+namespace mozilla {
+
+/**
+ * OffTheBooksMutex is identical to Mutex, except that OffTheBooksMutex doesn't
+ * include leak checking. Sometimes you want to intentionally "leak" a mutex
+ * until shutdown; in these cases, OffTheBooksMutex is for you.
+ */
+class OffTheBooksMutex : BlockingResourceBase
+{
+public:
+ /**
+ * @param aName A name which can reference this lock
+ * @returns If failure, nullptr
+ * If success, a valid Mutex* which must be destroyed
+ * by Mutex::DestroyMutex()
+ **/
+ explicit OffTheBooksMutex(const char* aName)
+ : BlockingResourceBase(aName, eMutex)
+ {
+ mLock = PR_NewLock();
+ if (!mLock) {
+ NS_RUNTIMEABORT("Can't allocate mozilla::Mutex");
+ }
+ }
+
+ ~OffTheBooksMutex()
+ {
+ NS_ASSERTION(mLock,
+ "improperly constructed Lock or double free");
+ // NSPR does consistency checks for us
+ PR_DestroyLock(mLock);
+ mLock = 0;
+ }
+
+#ifndef DEBUG
+ /**
+ * Lock
+ * @see prlock.h
+ **/
+ void Lock() { PR_Lock(mLock); }
+
+ /**
+ * Unlock
+ * @see prlock.h
+ **/
+ void Unlock() { PR_Unlock(mLock); }
+
+ /**
+ * AssertCurrentThreadOwns
+ * @see prlock.h
+ **/
+ void AssertCurrentThreadOwns() const {}
+
+ /**
+ * AssertNotCurrentThreadOwns
+ * @see prlock.h
+ **/
+ void AssertNotCurrentThreadOwns() const {}
+
+#else
+ void Lock();
+ void Unlock();
+
+ void AssertCurrentThreadOwns() const
+ {
+ PR_ASSERT_CURRENT_THREAD_OWNS_LOCK(mLock);
+ }
+
+ void AssertNotCurrentThreadOwns() const
+ {
+ // FIXME bug 476536
+ }
+
+#endif // ifndef DEBUG
+
+private:
+ OffTheBooksMutex();
+ OffTheBooksMutex(const OffTheBooksMutex&);
+ OffTheBooksMutex& operator=(const OffTheBooksMutex&);
+
+ PRLock* mLock;
+
+ friend class CondVar;
+
+ // MozPromise needs to access mLock for debugging purpose.
+ template<typename, typename, bool>
+ friend class MozPromise;
+};
+
+/**
+ * Mutex
+ * When possible, use MutexAutoLock/MutexAutoUnlock to lock/unlock this
+ * mutex within a scope, instead of calling Lock/Unlock directly.
+ */
+class Mutex : public OffTheBooksMutex
+{
+public:
+ explicit Mutex(const char* aName)
+ : OffTheBooksMutex(aName)
+ {
+ MOZ_COUNT_CTOR(Mutex);
+ }
+
+ ~Mutex()
+ {
+ MOZ_COUNT_DTOR(Mutex);
+ }
+
+private:
+ Mutex();
+ Mutex(const Mutex&);
+ Mutex& operator=(const Mutex&);
+};
+
+/**
+ * MutexAutoLock
+ * Acquires the Mutex when it enters scope, and releases it when it leaves
+ * scope.
+ *
+ * MUCH PREFERRED to bare calls to Mutex.Lock and Unlock.
+ */
+template<typename T>
+class MOZ_RAII BaseAutoLock
+{
+public:
+ /**
+ * Constructor
+ * The constructor aquires the given lock. The destructor
+ * releases the lock.
+ *
+ * @param aLock A valid mozilla::Mutex* returned by
+ * mozilla::Mutex::NewMutex.
+ **/
+ explicit BaseAutoLock(T& aLock MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+ : mLock(&aLock)
+ {
+ MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+ NS_ASSERTION(mLock, "null mutex");
+ mLock->Lock();
+ }
+
+ ~BaseAutoLock(void)
+ {
+ mLock->Unlock();
+ }
+
+private:
+ BaseAutoLock();
+ BaseAutoLock(BaseAutoLock&);
+ BaseAutoLock& operator=(BaseAutoLock&);
+ static void* operator new(size_t) CPP_THROW_NEW;
+
+ T* mLock;
+ MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
+};
+
+typedef BaseAutoLock<Mutex> MutexAutoLock;
+typedef BaseAutoLock<OffTheBooksMutex> OffTheBooksMutexAutoLock;
+
+/**
+ * MutexAutoUnlock
+ * Releases the Mutex when it enters scope, and re-acquires it when it leaves
+ * scope.
+ *
+ * MUCH PREFERRED to bare calls to Mutex.Unlock and Lock.
+ */
+template<typename T>
+class MOZ_RAII BaseAutoUnlock
+{
+public:
+ explicit BaseAutoUnlock(T& aLock MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+ : mLock(&aLock)
+ {
+ MOZ_GUARD_OBJECT_NOTIFIER_INIT;
+ NS_ASSERTION(mLock, "null lock");
+ mLock->Unlock();
+ }
+
+ ~BaseAutoUnlock()
+ {
+ mLock->Lock();
+ }
+
+private:
+ BaseAutoUnlock();
+ BaseAutoUnlock(BaseAutoUnlock&);
+ BaseAutoUnlock& operator=(BaseAutoUnlock&);
+ static void* operator new(size_t) CPP_THROW_NEW;
+
+ T* mLock;
+ MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
+};
+
+typedef BaseAutoUnlock<Mutex> MutexAutoUnlock;
+typedef BaseAutoUnlock<OffTheBooksMutex> OffTheBooksMutexAutoUnlock;
+
+} // namespace mozilla
+
+
+#endif // ifndef mozilla_Mutex_h