| // Copyright 2015 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "src/cancelable-task.h" |
| |
| #include "src/base/platform/platform.h" |
| #include "src/isolate.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| |
| Cancelable::Cancelable(CancelableTaskManager* parent) |
| : parent_(parent), status_(kWaiting), id_(0), cancel_counter_(0) { |
| id_ = parent->Register(this); |
| } |
| |
| |
| Cancelable::~Cancelable() { |
| // The following check is needed to avoid calling an already terminated |
| // manager object. This happens when the manager cancels all pending tasks |
| // in {CancelAndWait} only before destroying the manager object. |
| if (TryRun() || IsRunning()) { |
| parent_->RemoveFinishedTask(id_); |
| } |
| } |
| |
| CancelableTaskManager::CancelableTaskManager() : task_id_counter_(0) {} |
| |
| uint32_t CancelableTaskManager::Register(Cancelable* task) { |
| base::LockGuard<base::Mutex> guard(&mutex_); |
| uint32_t id = ++task_id_counter_; |
| // The loop below is just used when task_id_counter_ overflows. |
| while (cancelable_tasks_.count(id) > 0) ++id; |
| cancelable_tasks_[id] = task; |
| return id; |
| } |
| |
| |
| void CancelableTaskManager::RemoveFinishedTask(uint32_t id) { |
| base::LockGuard<base::Mutex> guard(&mutex_); |
| size_t removed = cancelable_tasks_.erase(id); |
| USE(removed); |
| DCHECK_NE(0, removed); |
| cancelable_tasks_barrier_.NotifyOne(); |
| } |
| |
| |
| bool CancelableTaskManager::TryAbort(uint32_t id) { |
| base::LockGuard<base::Mutex> guard(&mutex_); |
| auto entry = cancelable_tasks_.find(id); |
| if (entry != cancelable_tasks_.end()) { |
| Cancelable* value = entry->second; |
| if (value->Cancel()) { |
| // Cannot call RemoveFinishedTask here because of recursive locking. |
| cancelable_tasks_.erase(entry); |
| cancelable_tasks_barrier_.NotifyOne(); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| |
| void CancelableTaskManager::CancelAndWait() { |
| // Clean up all cancelable fore- and background tasks. Tasks are canceled on |
| // the way if possible, i.e., if they have not started yet. After each round |
| // of canceling we wait for the background tasks that have already been |
| // started. |
| base::LockGuard<base::Mutex> guard(&mutex_); |
| |
| // Cancelable tasks could be running or could potentially register new |
| // tasks, requiring a loop here. |
| while (!cancelable_tasks_.empty()) { |
| for (auto it = cancelable_tasks_.begin(); it != cancelable_tasks_.end();) { |
| auto current = it; |
| // We need to get to the next element before erasing the current. |
| ++it; |
| if (current->second->Cancel()) { |
| cancelable_tasks_.erase(current); |
| } |
| } |
| // Wait for already running background tasks. |
| if (!cancelable_tasks_.empty()) { |
| cancelable_tasks_barrier_.Wait(&mutex_); |
| } |
| } |
| } |
| |
| |
| CancelableTask::CancelableTask(Isolate* isolate) |
| : Cancelable(isolate->cancelable_task_manager()), isolate_(isolate) {} |
| |
| |
| CancelableIdleTask::CancelableIdleTask(Isolate* isolate) |
| : Cancelable(isolate->cancelable_task_manager()), isolate_(isolate) {} |
| |
| } // namespace internal |
| } // namespace v8 |