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 #include "content/browser/loader/offline_policy.h" 6 7 #include "base/command_line.h" 8 #include "base/metrics/histogram.h" 9 #include "content/public/common/content_switches.h" 10 #include "net/base/load_flags.h" 11 #include "net/http/http_response_info.h" 12 #include "net/url_request/url_request.h" 13 14 namespace content { 15 OfflinePolicy()16OfflinePolicy::OfflinePolicy() 17 : enabled_(CommandLine::ForCurrentProcess()->HasSwitch( 18 switches::kEnableOfflineCacheAccess)), 19 state_(INIT), 20 resource_loads_initiated_(0), 21 resource_loads_successfully_started_(0) {} 22 ~OfflinePolicy()23OfflinePolicy::~OfflinePolicy() { 24 RecordAndResetStats(); 25 } 26 RecordAndResetStats()27void OfflinePolicy::RecordAndResetStats() { 28 if (enabled_ && OFFLINE == state_ && 0 != resource_loads_initiated_) { 29 UMA_HISTOGRAM_PERCENTAGE( 30 "OfflinePolicy.SuccessfulResourceLoadPercentage", 31 (resource_loads_successfully_started_ * 100 / 32 resource_loads_initiated_)); 33 } 34 resource_loads_initiated_ = 0; 35 resource_loads_successfully_started_ = 0; 36 } 37 GetAdditionalLoadFlags(int current_flags,bool reset_state)38int OfflinePolicy::GetAdditionalLoadFlags(int current_flags, 39 bool reset_state) { 40 // Don't do anything if offline mode is disabled. 41 if (!enabled_) 42 return 0; 43 44 if (reset_state) { 45 RecordAndResetStats(); 46 state_ = INIT; 47 } 48 49 ++resource_loads_initiated_; 50 51 // If a consumer has requested something contradictory, it wins; we 52 // don't modify the load flags. 53 if (current_flags & 54 (net::LOAD_BYPASS_CACHE | net::LOAD_PREFERRING_CACHE | 55 net::LOAD_ONLY_FROM_CACHE | net::LOAD_FROM_CACHE_IF_OFFLINE | 56 net::LOAD_DISABLE_CACHE)) { 57 return 0; 58 } 59 60 switch(state_) { 61 case INIT: 62 return net::LOAD_FROM_CACHE_IF_OFFLINE; 63 case ONLINE: 64 return 0; 65 case OFFLINE: 66 return net::LOAD_ONLY_FROM_CACHE; 67 } 68 NOTREACHED(); 69 return 0; 70 } 71 UpdateStateForSuccessfullyStartedRequest(const net::HttpResponseInfo & response_info)72void OfflinePolicy::UpdateStateForSuccessfullyStartedRequest( 73 const net::HttpResponseInfo& response_info) { 74 // Don't do anything if offline mode is disabled. 75 if (!enabled_) 76 return; 77 78 // If we get here, we're going to be providing some amount of information 79 // to the renderer. 80 ++resource_loads_successfully_started_; 81 82 if (state_ != INIT) 83 // We've already made the decision for the rest of this set 84 // of navigations. 85 return; 86 87 if (response_info.server_data_unavailable) { 88 state_ = OFFLINE; 89 } else if (response_info.network_accessed) { 90 // If we got the response from the network or validated it as part 91 // of this request, that means our connection to the host is working. 92 state_ = ONLINE; 93 } 94 } 95 96 } // namespace content 97