Move CancelableTaskTracker to //base/task/CancelableTaskTracker.

chrome/common/cancelable_task_tracker.cc

-// Copyright (c) 2012 The Chromium 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 "chrome/common/cancelable_task_tracker.h"
-
-#include <utility>
-
-#include "base/bind.h"
-#include "base/callback_helpers.h"
-#include "base/compiler_specific.h"
-#include "base/location.h"
-#include "base/memory/ref_counted.h"
-#include "base/message_loop/message_loop_proxy.h"
-#include "base/synchronization/cancellation_flag.h"
-#include "base/task_runner.h"
-
-using base::Bind;
-using base::CancellationFlag;
-using base::Closure;
-using base::hash_map;
-using base::TaskRunner;
-
-namespace {
-
-void RunIfNotCanceled(const CancellationFlag* flag, const Closure& task) {
-  if (!flag->IsSet())
-    task.Run();
-}
-
-void RunIfNotCanceledThenUntrack(const CancellationFlag* flag,
-                                 const Closure& task,
-                                 const Closure& untrack) {
-  RunIfNotCanceled(flag, task);
-  untrack.Run();
-}
-
-bool IsCanceled(const CancellationFlag* flag,
-                base::ScopedClosureRunner* cleanup_runner) {
-  return flag->IsSet();
-}
-
-void RunAndDeleteFlag(const Closure& closure, const CancellationFlag* flag) {
-  closure.Run();
-  delete flag;
-}
-
-void RunOrPostToTaskRunner(TaskRunner* task_runner, const Closure& closure) {
-  if (task_runner->RunsTasksOnCurrentThread())
-    closure.Run();
-  else
-    task_runner->PostTask(FROM_HERE, closure);
-}
-
-}  // namespace
-
-// static
-const CancelableTaskTracker::TaskId CancelableTaskTracker::kBadTaskId = 0;
-
-CancelableTaskTracker::CancelableTaskTracker()
-    : weak_factory_(this),
-      next_id_(1) {}
-
-CancelableTaskTracker::~CancelableTaskTracker() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  TryCancelAll();
-}
-
-CancelableTaskTracker::TaskId CancelableTaskTracker::PostTask(
-    TaskRunner* task_runner,
-    const tracked_objects::Location& from_here,
-    const Closure& task) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  return PostTaskAndReply(task_runner, from_here, task, Bind(&base::DoNothing));
-}
-
-CancelableTaskTracker::TaskId CancelableTaskTracker::PostTaskAndReply(
-    TaskRunner* task_runner,
-    const tracked_objects::Location& from_here,
-    const Closure& task,
-    const Closure& reply) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  // We need a MessageLoop to run reply.
-  DCHECK(base::MessageLoopProxy::current().get());
-
-  // Owned by reply callback below.
-  CancellationFlag* flag = new CancellationFlag();
-
-  TaskId id = next_id_;
-  next_id_++;  // int64 is big enough that we ignore the potential overflow.
-
-  const Closure& untrack_closure = Bind(
-      &CancelableTaskTracker::Untrack, weak_factory_.GetWeakPtr(), id);
-  bool success = task_runner->PostTaskAndReply(
-      from_here,
-      Bind(&RunIfNotCanceled, flag, task),
-      Bind(&RunIfNotCanceledThenUntrack,
-           base::Owned(flag), reply, untrack_closure));
-
-  if (!success)
-    return kBadTaskId;
-
-  Track(id, flag);
-  return id;
-}
-
-CancelableTaskTracker::TaskId CancelableTaskTracker::NewTrackedTaskId(
-    IsCanceledCallback* is_canceled_cb) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(base::MessageLoopProxy::current().get());
-
-  TaskId id = next_id_;
-  next_id_++;  // int64 is big enough that we ignore the potential overflow.
-
-  // Will be deleted by |untrack_and_delete_flag| after Untrack().
-  CancellationFlag* flag = new CancellationFlag();
-
-  Closure untrack_and_delete_flag = Bind(
-      &RunAndDeleteFlag,
-      Bind(&CancelableTaskTracker::Untrack, weak_factory_.GetWeakPtr(), id),
-      flag);
-
-  // Will always run |untrack_and_delete_flag| on current MessageLoop.
-  base::ScopedClosureRunner* untrack_and_delete_flag_runner =
-      new base::ScopedClosureRunner(
-          Bind(&RunOrPostToTaskRunner,
-               base::MessageLoopProxy::current(),
-               untrack_and_delete_flag));
-
-  *is_canceled_cb = Bind(
-      &IsCanceled, flag, base::Owned(untrack_and_delete_flag_runner));
-
-  Track(id, flag);
-  return id;
-}
-
-void CancelableTaskTracker::TryCancel(TaskId id) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  hash_map<TaskId, CancellationFlag*>::const_iterator it = task_flags_.find(id);
-  if (it == task_flags_.end()) {
-    // Two possibilities:
-    //
-    //   1. The task has already been untracked.
-    //   2. The TaskId is bad or unknown.
-    //
-    // Since this function is best-effort, it's OK to ignore these.
-    return;
-  }
-  it->second->Set();
-}
-
-void CancelableTaskTracker::TryCancelAll() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  for (hash_map<TaskId, CancellationFlag*>::const_iterator it =
-           task_flags_.begin();
-       it != task_flags_.end();
-       ++it) {
-    it->second->Set();
-  }
-}
-
-bool CancelableTaskTracker::HasTrackedTasks() const {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  return !task_flags_.empty();
-}
-
-void CancelableTaskTracker::Track(TaskId id, CancellationFlag* flag) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  bool success = task_flags_.insert(std::make_pair(id, flag)).second;
-  DCHECK(success);
-}
-
-void CancelableTaskTracker::Untrack(TaskId id) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  size_t num = task_flags_.erase(id);
-  DCHECK_EQ(1u, num);
-}