blob: 9bbddca6b24a9f8483d7665d6512907c064157d7 [file] [log] [blame]
// 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), canceled_(false) {}
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;
CHECK(!canceled_);
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();
}
CancelableTaskManager::TryAbortResult 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 kTaskAborted;
} else {
return kTaskRunning;
}
}
return kTaskRemoved;
}
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_);
canceled_ = true;
// 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