Support for process-wide incidents in the safe browsing incident reporting service.

chrome/browser/safe_browsing/delayed_callback_runner.h

+// Copyright 2014 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 CHROME_BROWSER_SAFE_BROWSING_DELAYED_CALLBACK_RUNNER_H_
+#define CHROME_BROWSER_SAFE_BROWSING_DELAYED_CALLBACK_RUNNER_H_
+
+#include <list>
+
+#include "base/callback_forward.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/task_runner.h"
+#include "base/threading/thread_checker.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.
+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();
+
+  // Registers |callback| with the runner. A copy of |callback| is held until it
+  // is run.
+  void RegisterCallback(const base::Closure& callback);
+
+  // Starts running the callbacks after the delay.
+  void Start();
+
+ private:
+  typedef std::list<base::Closure> CallbackList;
+
+  // 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();
+
+  base::ThreadChecker thread_checker_;
+
+  // 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_;
+
+  // callbacks_.end() when no work is being done. Any other value otherwise.
+  CallbackList::iterator next_callback_;
+
+  // A timer upon the firing of which the next callback will be run.
+  base::DelayTimer<DelayedCallbackRunner> timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(DelayedCallbackRunner);
+};
+
+}  // namespace safe_browsing
+
+#endif  // CHROME_BROWSER_SAFE_BROWSING_DELAYED_CALLBACK_RUNNER_H_