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      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
     61