mirror of
https://github.com/kidfromjupiter/nearby.git
synced 2026-09-15 15:16:12 -04:00
Janusz Sobczak
8f887064ec
The flow below caused a dead-lock: 1. A lengthy task A is running on an executor. 2. Executor is destructed, or `Shutdown()` on another thread. The call blocks waiting for A to complete. 3. Task A executes another task B on the executor. The call blocks forever. PiperOrigin-RevId: 517495348
107 lines
3.4 KiB
C++
107 lines
3.4 KiB
C++
// Copyright 2020 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef PLATFORM_PUBLIC_SCHEDULED_EXECUTOR_H_
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#define PLATFORM_PUBLIC_SCHEDULED_EXECUTOR_H_
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#include <cstdint>
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#include <memory>
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#include "absl/base/thread_annotations.h"
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#include "absl/time/time.h"
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#include "internal/platform/cancelable.h"
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#include "internal/platform/cancellable_task.h"
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#include "internal/platform/implementation/platform.h"
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#include "internal/platform/implementation/scheduled_executor.h"
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#include "internal/platform/lockable.h"
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#include "internal/platform/monitored_runnable.h"
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#include "internal/platform/mutex.h"
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#include "internal/platform/mutex_lock.h"
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#include "internal/platform/runnable.h"
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#include "internal/platform/thread_check_callable.h"
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#include "internal/platform/thread_check_runnable.h"
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namespace nearby {
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// An Executor that can schedule commands to run after a given delay, or to
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// execute periodically.
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//
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// https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ScheduledExecutorService.html
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class ABSL_LOCKABLE ScheduledExecutor final : public Lockable {
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public:
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using Platform = api::ImplementationPlatform;
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ScheduledExecutor() : impl_(Platform::CreateScheduledExecutor()) {}
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ScheduledExecutor(ScheduledExecutor&& other) { *this = std::move(other); }
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~ScheduledExecutor() { DoShutdown(); }
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ScheduledExecutor& operator=(ScheduledExecutor&& other)
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ABSL_LOCKS_EXCLUDED(mutex_) {
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MutexLock lock(&mutex_);
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{
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MutexLock other_lock(&other.mutex_);
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impl_ = std::move(other.impl_);
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}
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return *this;
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}
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void Execute(const std::string& name, Runnable&& runnable)
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ABSL_LOCKS_EXCLUDED(mutex_) {
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MutexLock lock(&mutex_);
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if (impl_)
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impl_->Execute(MonitoredRunnable(
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name, ThreadCheckRunnable(this, std::move(runnable))));
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}
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void Execute(Runnable&& runnable) ABSL_LOCKS_EXCLUDED(mutex_) {
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MutexLock lock(&mutex_);
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if (impl_) impl_->Execute(ThreadCheckRunnable(this, std::move(runnable)));
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}
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void Shutdown() ABSL_LOCKS_EXCLUDED(mutex_) { DoShutdown(); }
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Cancelable Schedule(Runnable&& runnable, absl::Duration duration)
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ABSL_LOCKS_EXCLUDED(mutex_) {
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MutexLock lock(&mutex_);
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if (impl_) {
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auto task = std::make_shared<CancellableTask>(
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ThreadCheckRunnable(this, std::move(runnable)));
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return Cancelable(task,
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impl_->Schedule([task]() { (*task)(); }, duration));
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} else {
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return Cancelable();
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}
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}
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private:
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void DoShutdown() ABSL_LOCKS_EXCLUDED(mutex_) {
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std::unique_ptr<api::ScheduledExecutor> executor = ReleaseExecutor();
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if (executor) {
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executor->Shutdown();
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}
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}
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std::unique_ptr<api::ScheduledExecutor> ReleaseExecutor()
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ABSL_LOCKS_EXCLUDED(mutex_) {
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MutexLock lock(&mutex_);
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return std::move(impl_);
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}
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mutable Mutex mutex_;
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std::unique_ptr<api::ScheduledExecutor> ABSL_GUARDED_BY(mutex_) impl_;
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};
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} // namespace nearby
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#endif // PLATFORM_PUBLIC_SCHEDULED_EXECUTOR_H_
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