1 // Copyright (c) 2012 The Chromium 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.
5 #include "chrome/common/cancelable_task_tracker.h"
10 #include "base/callback_helpers.h"
11 #include "base/compiler_specific.h"
12 #include "base/location.h"
13 #include "base/memory/ref_counted.h"
14 #include "base/message_loop/message_loop_proxy.h"
15 #include "base/synchronization/cancellation_flag.h"
16 #include "base/task_runner.h"
19 using base::CancellationFlag;
22 using base::TaskRunner;
26 void RunIfNotCanceled(const CancellationFlag* flag, const Closure& task) {
31 void RunIfNotCanceledThenUntrack(const CancellationFlag* flag,
33 const Closure& untrack) {
34 RunIfNotCanceled(flag, task);
38 bool IsCanceled(const CancellationFlag* flag,
39 base::ScopedClosureRunner* cleanup_runner) {
43 void RunAndDeleteFlag(const Closure& closure, const CancellationFlag* flag) {
48 void RunOrPostToTaskRunner(TaskRunner* task_runner, const Closure& closure) {
49 if (task_runner->RunsTasksOnCurrentThread())
52 task_runner->PostTask(FROM_HERE, closure);
58 const CancelableTaskTracker::TaskId CancelableTaskTracker::kBadTaskId = 0;
60 CancelableTaskTracker::CancelableTaskTracker()
61 : weak_factory_(this),
64 CancelableTaskTracker::~CancelableTaskTracker() {
65 DCHECK(thread_checker_.CalledOnValidThread());
70 CancelableTaskTracker::TaskId CancelableTaskTracker::PostTask(
71 TaskRunner* task_runner,
72 const tracked_objects::Location& from_here,
73 const Closure& task) {
74 DCHECK(thread_checker_.CalledOnValidThread());
76 return PostTaskAndReply(task_runner, from_here, task, Bind(&base::DoNothing));
79 CancelableTaskTracker::TaskId CancelableTaskTracker::PostTaskAndReply(
80 TaskRunner* task_runner,
81 const tracked_objects::Location& from_here,
83 const Closure& reply) {
84 DCHECK(thread_checker_.CalledOnValidThread());
86 // We need a MessageLoop to run reply.
87 DCHECK(base::MessageLoopProxy::current().get());
89 // Owned by reply callback below.
90 CancellationFlag* flag = new CancellationFlag();
93 next_id_++; // int64 is big enough that we ignore the potential overflow.
95 const Closure& untrack_closure = Bind(
96 &CancelableTaskTracker::Untrack, weak_factory_.GetWeakPtr(), id);
97 bool success = task_runner->PostTaskAndReply(
99 Bind(&RunIfNotCanceled, flag, task),
100 Bind(&RunIfNotCanceledThenUntrack,
101 base::Owned(flag), reply, untrack_closure));
110 CancelableTaskTracker::TaskId CancelableTaskTracker::NewTrackedTaskId(
111 IsCanceledCallback* is_canceled_cb) {
112 DCHECK(thread_checker_.CalledOnValidThread());
113 DCHECK(base::MessageLoopProxy::current().get());
115 TaskId id = next_id_;
116 next_id_++; // int64 is big enough that we ignore the potential overflow.
118 // Will be deleted by |untrack_and_delete_flag| after Untrack().
119 CancellationFlag* flag = new CancellationFlag();
121 Closure untrack_and_delete_flag = Bind(
123 Bind(&CancelableTaskTracker::Untrack, weak_factory_.GetWeakPtr(), id),
126 // Will always run |untrack_and_delete_flag| on current MessageLoop.
127 base::ScopedClosureRunner* untrack_and_delete_flag_runner =
128 new base::ScopedClosureRunner(
129 Bind(&RunOrPostToTaskRunner,
130 base::MessageLoopProxy::current(),
131 untrack_and_delete_flag));
133 *is_canceled_cb = Bind(
134 &IsCanceled, flag, base::Owned(untrack_and_delete_flag_runner));
140 void CancelableTaskTracker::TryCancel(TaskId id) {
141 DCHECK(thread_checker_.CalledOnValidThread());
143 hash_map<TaskId, CancellationFlag*>::const_iterator it = task_flags_.find(id);
144 if (it == task_flags_.end()) {
145 // Two possibilities:
147 // 1. The task has already been untracked.
148 // 2. The TaskId is bad or unknown.
150 // Since this function is best-effort, it's OK to ignore these.
156 void CancelableTaskTracker::TryCancelAll() {
157 DCHECK(thread_checker_.CalledOnValidThread());
159 for (hash_map<TaskId, CancellationFlag*>::const_iterator it =
161 it != task_flags_.end();
167 bool CancelableTaskTracker::HasTrackedTasks() const {
168 DCHECK(thread_checker_.CalledOnValidThread());
169 return !task_flags_.empty();
172 void CancelableTaskTracker::Track(TaskId id, CancellationFlag* flag) {
173 DCHECK(thread_checker_.CalledOnValidThread());
175 bool success = task_flags_.insert(std::make_pair(id, flag)).second;
179 void CancelableTaskTracker::Untrack(TaskId id) {
180 DCHECK(thread_checker_.CalledOnValidThread());
181 size_t num = task_flags_.erase(id);