1// Copyright 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.
4
5#ifndef CHROME_BROWSER_NET_TIMED_CACHE_H_
6#define CHROME_BROWSER_NET_TIMED_CACHE_H_
7
8#include "base/basictypes.h"
9#include "base/containers/mru_cache.h"
10#include "base/time/time.h"
11
12class GURL;
13
14namespace chrome_browser_net {
15
16// Define a LRU cache that recalls all navigations within the last N seconds.
17// When we learn about subresources to possibly preconnect to, it would be a
18// waste to preconnect when the original navigation was too long ago.  Any
19// connected, but unused TCP/IP connection, will generally be reset by the
20// server if it is not used quickly (i.e., GET or POST is sent).
21class TimedCache {
22 public:
23  explicit TimedCache(const base::TimeDelta& max_duration);
24  ~TimedCache();
25
26  // Evicts any entries that have been in the FIFO "too long," and then checks
27  // to see if the given url is (still) in the FIFO cache.
28  bool WasRecentlySeen(const GURL& url);
29
30  // Adds the given url to the cache, where it will remain for max_duration_.
31  void SetRecentlySeen(const GURL& url);
32
33 private:
34  // Our cache will be keyed on a URL (actually, just a scheme/host/port).
35  // We will always track the time it was last added to the FIFO cache by
36  // remembering a TimeTicks value.
37  typedef base::MRUCache<GURL, base::TimeTicks> UrlMruTimedCache;
38  UrlMruTimedCache mru_cache_;
39
40  // The longest time an entry can persist in the cache, and still be found.
41  const base::TimeDelta max_duration_;
42
43  DISALLOW_COPY_AND_ASSIGN(TimedCache);
44};
45
46}  // namespace chrome_browser_net
47
48#endif  // CHROME_BROWSER_NET_TIMED_CACHE_H_
49