chrome/browser/net/timed_cache.h

   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
  12 class GURL;
  13
  14 namespace 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).
  21 class 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_