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// Copyright 2015 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.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_WEB_TASK_RUNNER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_WEB_TASK_RUNNER_H_
#include <memory>
#include "base/callback.h"
#include "base/location.h"
#include "base/sequenced_task_runner.h"
#include "third_party/blink/public/platform/web_common.h"
#include "third_party/blink/renderer/platform/wtf/compiler.h"
#include "third_party/blink/renderer/platform/wtf/functional.h"
#include "third_party/blink/renderer/platform/wtf/ref_counted.h"
#include "third_party/blink/renderer/platform/wtf/time.h"
namespace blink {
// TaskHandle is associated to a task posted by PostCancellableTask() or
// PostCancellableDelayedTask() and cancels the associated task on
// TaskHandle::cancel() call or on TaskHandle destruction.
class BLINK_PLATFORM_EXPORT TaskHandle {
public:
// Returns true if the task will run later. Returns false if the task is
// cancelled or the task is run already.
// This function is not thread safe. Call this on the thread that has posted
// the task.
bool IsActive() const;
// Cancels the task invocation. Do nothing if the task is cancelled or run
// already.
// This function is not thread safe. Call this on the thread that has posted
// the task.
void Cancel();
TaskHandle();
~TaskHandle();
TaskHandle(TaskHandle&&);
TaskHandle& operator=(TaskHandle&&);
class Runner;
private:
friend BLINK_PLATFORM_EXPORT WARN_UNUSED_RESULT TaskHandle
PostCancellableTask(base::SequencedTaskRunner&,
const base::Location&,
base::OnceClosure);
friend BLINK_PLATFORM_EXPORT WARN_UNUSED_RESULT TaskHandle
PostDelayedCancellableTask(base::SequencedTaskRunner&,
const base::Location&,
base::OnceClosure,
TimeDelta delay);
explicit TaskHandle(scoped_refptr<Runner>);
scoped_refptr<Runner> runner_;
};
// For cross-thread posting. Can be called from any thread.
BLINK_PLATFORM_EXPORT void PostCrossThreadTask(base::SequencedTaskRunner&,
const base::Location&,
CrossThreadClosure);
BLINK_PLATFORM_EXPORT void PostDelayedCrossThreadTask(
base::SequencedTaskRunner&,
const base::Location&,
CrossThreadClosure,
TimeDelta delay);
// For same-thread cancellable task posting. Returns a TaskHandle object for
// cancellation.
BLINK_PLATFORM_EXPORT WARN_UNUSED_RESULT TaskHandle
PostCancellableTask(base::SequencedTaskRunner&,
const base::Location&,
base::OnceClosure);
BLINK_PLATFORM_EXPORT WARN_UNUSED_RESULT TaskHandle
PostDelayedCancellableTask(base::SequencedTaskRunner&,
const base::Location&,
base::OnceClosure,
TimeDelta delay);
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_WEB_TASK_RUNNER_H_
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