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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_SAFE_BROWSING_INCIDENT_REPORTING_DELAYED_CALLBACK_RUNNER_H_
#define CHROME_BROWSER_SAFE_BROWSING_INCIDENT_REPORTING_DELAYED_CALLBACK_RUNNER_H_
#include "base/containers/queue.h"
#include "base/functional/callback_forward.h"
#include "base/memory/scoped_refptr.h"
#include "base/task/task_runner.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
namespace safe_browsing {
// Runs callbacks on a given task runner, waiting a certain amount of time
// between each. The delay also applies to running the first callback (i.e.,
// the first callback will be run some time after Start() is invoked). Callbacks
// are deleted after they are run. Start() is idempotent: calling it while the
// runner is doing its job has no effect.
// Lives on the UI thread.
class DelayedCallbackRunner {
public:
// Constructs an instance that runs tasks on |callback_runner|, waiting for
// |delay| time to pass before and between each callback.
DelayedCallbackRunner(base::TimeDelta delay,
const scoped_refptr<base::TaskRunner>& task_runner);
DelayedCallbackRunner(const DelayedCallbackRunner&) = delete;
DelayedCallbackRunner& operator=(const DelayedCallbackRunner&) = delete;
~DelayedCallbackRunner();
// Registers |callback| with the runner. A copy of |callback| is held until it
// is run.
void RegisterCallback(base::OnceClosure callback);
// Starts running the callbacks after the delay.
void Start();
private:
using CallbackList = base::queue<base::OnceClosure>;
// A callback invoked by the timer to run the next callback. The timer is
// restarted to process the next callback if there is one.
void OnTimer();
// The runner on which callbacks are to be run.
scoped_refptr<base::TaskRunner> task_runner_;
// The list of callbacks to run. Callbacks are removed when run.
CallbackList callbacks_;
// Whethere there is work to be done from |callbacks_|.
bool has_work_;
// A timer upon the firing of which the next callback will be run.
base::DelayTimer timer_;
};
} // namespace safe_browsing
#endif // CHROME_BROWSER_SAFE_BROWSING_INCIDENT_REPORTING_DELAYED_CALLBACK_RUNNER_H_
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