// Copyright 2015 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/cancelable-task.h"
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#include "src/base/platform/platform.h"
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#include "src/isolate.h"
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namespace v8 {
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namespace internal {
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Cancelable::Cancelable(CancelableTaskManager* parent)
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: parent_(parent), status_(kWaiting), id_(0), cancel_counter_(0) {
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id_ = parent->Register(this);
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}
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Cancelable::~Cancelable() {
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// The following check is needed to avoid calling an already terminated
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// manager object. This happens when the manager cancels all pending tasks
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// in {CancelAndWait} only before destroying the manager object.
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if (TryRun() || IsRunning()) {
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parent_->RemoveFinishedTask(id_);
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}
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}
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CancelableTaskManager::CancelableTaskManager()
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: task_id_counter_(0), canceled_(false) {}
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CancelableTaskManager::Id CancelableTaskManager::Register(Cancelable* task) {
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base::LockGuard<base::Mutex> guard(&mutex_);
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CancelableTaskManager::Id id = ++task_id_counter_;
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// Id overflows are not supported.
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CHECK_NE(0, id);
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CHECK(!canceled_);
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cancelable_tasks_[id] = task;
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return id;
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}
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void CancelableTaskManager::RemoveFinishedTask(CancelableTaskManager::Id id) {
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base::LockGuard<base::Mutex> guard(&mutex_);
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size_t removed = cancelable_tasks_.erase(id);
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USE(removed);
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DCHECK_NE(0u, removed);
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cancelable_tasks_barrier_.NotifyOne();
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}
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CancelableTaskManager::TryAbortResult CancelableTaskManager::TryAbort(
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CancelableTaskManager::Id id) {
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base::LockGuard<base::Mutex> guard(&mutex_);
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auto entry = cancelable_tasks_.find(id);
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if (entry != cancelable_tasks_.end()) {
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Cancelable* value = entry->second;
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if (value->Cancel()) {
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// Cannot call RemoveFinishedTask here because of recursive locking.
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cancelable_tasks_.erase(entry);
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cancelable_tasks_barrier_.NotifyOne();
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return kTaskAborted;
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} else {
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return kTaskRunning;
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}
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}
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return kTaskRemoved;
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}
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void CancelableTaskManager::CancelAndWait() {
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// Clean up all cancelable fore- and background tasks. Tasks are canceled on
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// the way if possible, i.e., if they have not started yet. After each round
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// of canceling we wait for the background tasks that have already been
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// started.
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base::LockGuard<base::Mutex> guard(&mutex_);
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canceled_ = true;
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// Cancelable tasks could be running or could potentially register new
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// tasks, requiring a loop here.
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while (!cancelable_tasks_.empty()) {
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for (auto it = cancelable_tasks_.begin(); it != cancelable_tasks_.end();) {
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auto current = it;
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// We need to get to the next element before erasing the current.
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++it;
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if (current->second->Cancel()) {
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cancelable_tasks_.erase(current);
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}
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}
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// Wait for already running background tasks.
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if (!cancelable_tasks_.empty()) {
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cancelable_tasks_barrier_.Wait(&mutex_);
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}
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}
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}
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CancelableTaskManager::TryAbortResult CancelableTaskManager::TryAbortAll() {
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// Clean up all cancelable fore- and background tasks. Tasks are canceled on
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// the way if possible, i.e., if they have not started yet.
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base::LockGuard<base::Mutex> guard(&mutex_);
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if (cancelable_tasks_.empty()) return kTaskRemoved;
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for (auto it = cancelable_tasks_.begin(); it != cancelable_tasks_.end();) {
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if (it->second->Cancel()) {
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it = cancelable_tasks_.erase(it);
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} else {
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++it;
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}
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}
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return cancelable_tasks_.empty() ? kTaskAborted : kTaskRunning;
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}
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CancelableTask::CancelableTask(Isolate* isolate)
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: CancelableTask(isolate->cancelable_task_manager()) {}
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CancelableTask::CancelableTask(CancelableTaskManager* manager)
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: Cancelable(manager) {}
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CancelableIdleTask::CancelableIdleTask(Isolate* isolate)
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: CancelableIdleTask(isolate->cancelable_task_manager()) {}
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CancelableIdleTask::CancelableIdleTask(CancelableTaskManager* manager)
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: Cancelable(manager) {}
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} // namespace internal
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} // namespace v8
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