diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /xpcom/base/StaticMonitor.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'xpcom/base/StaticMonitor.h')
-rw-r--r-- | xpcom/base/StaticMonitor.h | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/xpcom/base/StaticMonitor.h b/xpcom/base/StaticMonitor.h new file mode 100644 index 0000000000..b35d3871d2 --- /dev/null +++ b/xpcom/base/StaticMonitor.h @@ -0,0 +1,117 @@ +/* -*- 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_StaticMonitor_h +#define mozilla_StaticMonitor_h + +#include "mozilla/Atomics.h" +#include "mozilla/CondVar.h" +#include "mozilla/ThreadSafety.h" + +namespace mozilla { + +class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS MOZ_CAPABILITY("monitor") + StaticMonitor { + public: + // In debug builds, check that mMutex is initialized for us as we expect by + // the compiler. In non-debug builds, don't declare a constructor so that + // the compiler can see that the constructor is trivial. +#ifdef DEBUG + StaticMonitor() { MOZ_ASSERT(!mMutex); } +#endif + + void Lock() MOZ_CAPABILITY_ACQUIRE() { Mutex()->Lock(); } + + void Unlock() MOZ_CAPABILITY_RELEASE() { Mutex()->Unlock(); } + + void Wait() { CondVar()->Wait(); } + CVStatus Wait(TimeDuration aDuration) { + AssertCurrentThreadOwns(); + return CondVar()->Wait(aDuration); + } + + void Notify() { CondVar()->Notify(); } + void NotifyAll() { CondVar()->NotifyAll(); } + + void AssertCurrentThreadOwns() MOZ_ASSERT_CAPABILITY(this) { +#ifdef DEBUG + Mutex()->AssertCurrentThreadOwns(); +#endif + } + + private: + OffTheBooksMutex* Mutex() { + if (mMutex) { + return mMutex; + } + + OffTheBooksMutex* mutex = new OffTheBooksMutex("StaticMutex"); + if (!mMutex.compareExchange(nullptr, mutex)) { + delete mutex; + } + + return mMutex; + } + + OffTheBooksCondVar* CondVar() { + if (mCondVar) { + return mCondVar; + } + + OffTheBooksCondVar* condvar = + new OffTheBooksCondVar(*Mutex(), "StaticCondVar"); + if (!mCondVar.compareExchange(nullptr, condvar)) { + delete condvar; + } + + return mCondVar; + } + + Atomic<OffTheBooksMutex*> mMutex; + Atomic<OffTheBooksCondVar*> mCondVar; + + // Disallow copy constructor, but only in debug mode. We only define + // a default constructor in debug mode (see above); if we declared + // this constructor always, the compiler wouldn't generate a trivial + // default constructor for us in non-debug mode. +#ifdef DEBUG + StaticMonitor(const StaticMonitor& aOther); +#endif + + // Disallow these operators. + StaticMonitor& operator=(const StaticMonitor& aRhs); + static void* operator new(size_t) noexcept(true); + static void operator delete(void*); +}; + +class MOZ_STACK_CLASS MOZ_SCOPED_CAPABILITY StaticMonitorAutoLock { + public: + explicit StaticMonitorAutoLock(StaticMonitor& aMonitor) + MOZ_CAPABILITY_ACQUIRE(aMonitor) + : mMonitor(&aMonitor) { + mMonitor->Lock(); + } + + ~StaticMonitorAutoLock() MOZ_CAPABILITY_RELEASE() { mMonitor->Unlock(); } + + void Wait() { mMonitor->Wait(); } + CVStatus Wait(TimeDuration aDuration) { return mMonitor->Wait(aDuration); } + + void Notify() { mMonitor->Notify(); } + void NotifyAll() { mMonitor->NotifyAll(); } + + private: + StaticMonitorAutoLock(); + StaticMonitorAutoLock(const StaticMonitorAutoLock&); + StaticMonitorAutoLock& operator=(const StaticMonitorAutoLock&); + static void* operator new(size_t) noexcept(true); + + StaticMonitor* mMonitor; +}; + +} // namespace mozilla + +#endif |