forked from mirrors/gecko-dev
f8e46f7fb5
It is possible to specify full names for capabilities when using the clang thread-safety analysis which will be used in error messages. We should use that form of the attribute rather than the legacy lockable attribute. Differential Revision: https://phabricator.services.mozilla.com/D160531
117 lines
3.2 KiB
C++
117 lines
3.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_StaticMonitor_h
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#define mozilla_StaticMonitor_h
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#include "mozilla/Atomics.h"
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#include "mozilla/CondVar.h"
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#include "mozilla/ThreadSafety.h"
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namespace mozilla {
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class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS MOZ_CAPABILITY("monitor")
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StaticMonitor {
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public:
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// In debug builds, check that mMutex is initialized for us as we expect by
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// the compiler. In non-debug builds, don't declare a constructor so that
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// the compiler can see that the constructor is trivial.
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#ifdef DEBUG
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StaticMonitor() { MOZ_ASSERT(!mMutex); }
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#endif
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void Lock() MOZ_CAPABILITY_ACQUIRE() { Mutex()->Lock(); }
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void Unlock() MOZ_CAPABILITY_RELEASE() { Mutex()->Unlock(); }
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void Wait() { CondVar()->Wait(); }
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CVStatus Wait(TimeDuration aDuration) {
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AssertCurrentThreadOwns();
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return CondVar()->Wait(aDuration);
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}
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void Notify() { CondVar()->Notify(); }
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void NotifyAll() { CondVar()->NotifyAll(); }
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void AssertCurrentThreadOwns() MOZ_ASSERT_CAPABILITY(this) {
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#ifdef DEBUG
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Mutex()->AssertCurrentThreadOwns();
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#endif
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}
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private:
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OffTheBooksMutex* Mutex() {
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if (mMutex) {
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return mMutex;
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}
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OffTheBooksMutex* mutex = new OffTheBooksMutex("StaticMutex");
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if (!mMutex.compareExchange(nullptr, mutex)) {
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delete mutex;
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}
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return mMutex;
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}
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OffTheBooksCondVar* CondVar() {
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if (mCondVar) {
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return mCondVar;
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}
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OffTheBooksCondVar* condvar =
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new OffTheBooksCondVar(*Mutex(), "StaticCondVar");
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if (!mCondVar.compareExchange(nullptr, condvar)) {
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delete condvar;
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}
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return mCondVar;
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}
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Atomic<OffTheBooksMutex*> mMutex;
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Atomic<OffTheBooksCondVar*> mCondVar;
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// Disallow copy constructor, but only in debug mode. We only define
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// a default constructor in debug mode (see above); if we declared
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// this constructor always, the compiler wouldn't generate a trivial
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// default constructor for us in non-debug mode.
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#ifdef DEBUG
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StaticMonitor(const StaticMonitor& aOther);
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#endif
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// Disallow these operators.
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StaticMonitor& operator=(const StaticMonitor& aRhs);
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static void* operator new(size_t) noexcept(true);
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static void operator delete(void*);
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};
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class MOZ_STACK_CLASS MOZ_SCOPED_CAPABILITY StaticMonitorAutoLock {
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public:
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explicit StaticMonitorAutoLock(StaticMonitor& aMonitor)
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MOZ_CAPABILITY_ACQUIRE(aMonitor)
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: mMonitor(&aMonitor) {
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mMonitor->Lock();
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}
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~StaticMonitorAutoLock() MOZ_CAPABILITY_RELEASE() { mMonitor->Unlock(); }
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void Wait() { mMonitor->Wait(); }
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CVStatus Wait(TimeDuration aDuration) { return mMonitor->Wait(aDuration); }
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void Notify() { mMonitor->Notify(); }
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void NotifyAll() { mMonitor->NotifyAll(); }
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private:
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StaticMonitorAutoLock();
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StaticMonitorAutoLock(const StaticMonitorAutoLock&);
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StaticMonitorAutoLock& operator=(const StaticMonitorAutoLock&);
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static void* operator new(size_t) noexcept(true);
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StaticMonitor* mMonitor;
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};
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} // namespace mozilla
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#endif
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