1 // Copyright (c) 2013 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 #ifndef CHROME_BROWSER_POLICY_CLOUD_RATE_LIMITER_H_
6 #define CHROME_BROWSER_POLICY_CLOUD_RATE_LIMITER_H_
10 #include "base/basictypes.h"
11 #include "base/callback.h"
12 #include "base/cancelable_callback.h"
13 #include "base/memory/ref_counted.h"
14 #include "base/memory/scoped_ptr.h"
15 #include "base/threading/non_thread_safe.h"
16 #include "base/time/time.h"
19 class SequencedTaskRunner;
25 // A simple class to limit the rate at which a callback is invoked.
26 class RateLimiter : public base::NonThreadSafe {
28 // Will limit invocations of |callback| to |max_requests| per |duration|.
29 // |task_runner| is used to post delayed tasks, and |clock| is used to
30 // measure elapsed time.
31 RateLimiter(size_t max_requests,
32 const base::TimeDelta& duration,
33 const base::Closure& callback,
34 scoped_refptr<base::SequencedTaskRunner> task_runner,
35 scoped_ptr<base::TickClock> clock);
38 // Posts a request to invoke |callback_|. It is invoked immediately if the
39 // rate in the preceding |duration_| period is within the limit, otherwise
40 // the callback will be invoked later, ensuring the allowed rate is not
45 const size_t max_requests_;
46 const base::TimeDelta duration_;
47 base::Closure callback_;
48 scoped_refptr<base::SequencedTaskRunner> task_runner_;
49 scoped_ptr<base::TickClock> clock_;
51 std::queue<base::TimeTicks> invocation_times_;
52 base::CancelableClosure delayed_callback_;
54 DISALLOW_COPY_AND_ASSIGN(RateLimiter);
59 #endif // CHROME_BROWSER_POLICY_CLOUD_RATE_LIMITER_H_