1// Copyright 2015 the V8 project authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include "src/cancelable-task.h" 6 7#include "src/base/platform/platform.h" 8#include "src/isolate.h" 9 10namespace v8 { 11namespace internal { 12 13 14Cancelable::Cancelable(CancelableTaskManager* parent) 15 : parent_(parent), status_(kWaiting), id_(0), cancel_counter_(0) { 16 id_ = parent->Register(this); 17} 18 19 20Cancelable::~Cancelable() { 21 // The following check is needed to avoid calling an already terminated 22 // manager object. This happens when the manager cancels all pending tasks 23 // in {CancelAndWait} only before destroying the manager object. 24 if (TryRun() || IsRunning()) { 25 parent_->RemoveFinishedTask(id_); 26 } 27} 28 29CancelableTaskManager::CancelableTaskManager() 30 : task_id_counter_(0), canceled_(false) {} 31 32uint32_t CancelableTaskManager::Register(Cancelable* task) { 33 base::LockGuard<base::Mutex> guard(&mutex_); 34 uint32_t id = ++task_id_counter_; 35 // The loop below is just used when task_id_counter_ overflows. 36 while (cancelable_tasks_.count(id) > 0) ++id; 37 CHECK(!canceled_); 38 cancelable_tasks_[id] = task; 39 return id; 40} 41 42 43void CancelableTaskManager::RemoveFinishedTask(uint32_t id) { 44 base::LockGuard<base::Mutex> guard(&mutex_); 45 size_t removed = cancelable_tasks_.erase(id); 46 USE(removed); 47 DCHECK_NE(0u, removed); 48 cancelable_tasks_barrier_.NotifyOne(); 49} 50 51CancelableTaskManager::TryAbortResult CancelableTaskManager::TryAbort( 52 uint32_t id) { 53 base::LockGuard<base::Mutex> guard(&mutex_); 54 auto entry = cancelable_tasks_.find(id); 55 if (entry != cancelable_tasks_.end()) { 56 Cancelable* value = entry->second; 57 if (value->Cancel()) { 58 // Cannot call RemoveFinishedTask here because of recursive locking. 59 cancelable_tasks_.erase(entry); 60 cancelable_tasks_barrier_.NotifyOne(); 61 return kTaskAborted; 62 } else { 63 return kTaskRunning; 64 } 65 } 66 return kTaskRemoved; 67} 68 69 70void CancelableTaskManager::CancelAndWait() { 71 // Clean up all cancelable fore- and background tasks. Tasks are canceled on 72 // the way if possible, i.e., if they have not started yet. After each round 73 // of canceling we wait for the background tasks that have already been 74 // started. 75 base::LockGuard<base::Mutex> guard(&mutex_); 76 canceled_ = true; 77 78 // Cancelable tasks could be running or could potentially register new 79 // tasks, requiring a loop here. 80 while (!cancelable_tasks_.empty()) { 81 for (auto it = cancelable_tasks_.begin(); it != cancelable_tasks_.end();) { 82 auto current = it; 83 // We need to get to the next element before erasing the current. 84 ++it; 85 if (current->second->Cancel()) { 86 cancelable_tasks_.erase(current); 87 } 88 } 89 // Wait for already running background tasks. 90 if (!cancelable_tasks_.empty()) { 91 cancelable_tasks_barrier_.Wait(&mutex_); 92 } 93 } 94} 95 96CancelableTaskManager::TryAbortResult CancelableTaskManager::TryAbortAll() { 97 // Clean up all cancelable fore- and background tasks. Tasks are canceled on 98 // the way if possible, i.e., if they have not started yet. 99 base::LockGuard<base::Mutex> guard(&mutex_); 100 101 if (cancelable_tasks_.empty()) return kTaskRemoved; 102 103 for (auto it = cancelable_tasks_.begin(); it != cancelable_tasks_.end();) { 104 if (it->second->Cancel()) { 105 it = cancelable_tasks_.erase(it); 106 } else { 107 ++it; 108 } 109 } 110 111 return cancelable_tasks_.empty() ? kTaskAborted : kTaskRunning; 112} 113 114CancelableTask::CancelableTask(Isolate* isolate) 115 : CancelableTask(isolate, isolate->cancelable_task_manager()) {} 116 117CancelableTask::CancelableTask(Isolate* isolate, CancelableTaskManager* manager) 118 : Cancelable(manager), isolate_(isolate) {} 119 120CancelableIdleTask::CancelableIdleTask(Isolate* isolate) 121 : CancelableIdleTask(isolate, isolate->cancelable_task_manager()) {} 122 123CancelableIdleTask::CancelableIdleTask(Isolate* isolate, 124 CancelableTaskManager* manager) 125 : Cancelable(manager), isolate_(isolate) {} 126 127} // namespace internal 128} // namespace v8 129