content/browser/loader/offline_policy.h

   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.
   4
   5 #ifndef CONTENT_BROWSER_LOADER_OFFLINE_POLICY
   6 #define CONTENT_BROWSER_LOADER_OFFLINE_POLICY
   7
   8 #include <map>
   9
  10 #include "base/basictypes.h"
  11 #include "content/common/content_export.h"
  12
  13 struct ResourceHostMsg_Request;
  14
  15 namespace net {
  16 class HttpResponseInfo;
  17 class URLRequest;
  18 }
  19
  20 namespace content {
  21
  22 // This class controls under what conditions resources will be fetched
  23 // from cache even if stale rather than from the network.  For example,
  24 // one policy would be that if requests for a particular route (e.g. "tab")
  25 // is unable to reach the server, other requests made with the same route
  26 // can be loaded from cache without first requiring a network timeout.
  27 //
  28 // There is a single OfflinePolicy object per user navigation unit
  29 // (generally a tab).
  30 class CONTENT_EXPORT OfflinePolicy {
  31  public:
  32   OfflinePolicy();
  33   ~OfflinePolicy();
  34
  35   // Return any additional load flags to be ORed for a request from
  36   // this route with the given |resource_type|.  |reset_state| indicates
  37   // that this request should reinitialized the internal state for this
  38   // policy object (e.g. in the case of a main frame load).
  39   int GetAdditionalLoadFlags(int current_flags, bool reset_state);
  40
  41   // Incorporate online/offline information from a successfully started request.
  42   void UpdateStateForSuccessfullyStartedRequest(
  43       const net::HttpResponseInfo& response_info);
  44
  45 private:
  46   enum State { INIT, ONLINE, OFFLINE };
  47
  48   void RecordAndResetStats();
  49
  50   bool enabled_;
  51   State state_;
  52   int resource_loads_initiated_;
  53   int resource_loads_successfully_started_;
  54
  55   DISALLOW_COPY_AND_ASSIGN(OfflinePolicy);
  56 };
  57
  58 }  // namespace content
  59
  60 #endif  // CONTENT_BROWSER_LOADER_OFFLINE_POLICY