1 // Copyright (c) 2012 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_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_ 6 #define CHROME_BROWSER_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_ 7 8 #include <string> 9 10 #include "base/memory/ref_counted.h" 11 #include "base/memory/scoped_ptr.h" 12 #include "base/memory/weak_ptr.h" 13 #include "chrome/browser/web_resource/json_asynchronous_unpacker.h" 14 #include "chrome/browser/web_resource/resource_request_allowed_notifier.h" 15 #include "net/url_request/url_fetcher_delegate.h" 16 #include "url/gurl.h" 17 18 class PrefService; 19 20 namespace base { 21 class DictionaryValue; 22 } 23 24 namespace net { 25 class URLFetcher; 26 } 27 28 // A WebResourceService fetches JSON data from a web server and periodically 29 // refreshes it. 30 class WebResourceService 31 : public net::URLFetcherDelegate, 32 public JSONAsynchronousUnpackerDelegate, 33 public base::RefCountedThreadSafe<WebResourceService>, 34 public ResourceRequestAllowedNotifier::Observer { 35 public: 36 WebResourceService(PrefService* prefs, 37 const GURL& web_resource_server, 38 bool apply_locale_to_url_, 39 const char* last_update_time_pref_name, 40 int start_fetch_delay_ms, 41 int cache_update_delay_ms); 42 43 // Sleep until cache needs to be updated, but always for at least 44 // |start_fetch_delay_ms| so we don't interfere with startup. 45 // Then begin updating resources. 46 void StartAfterDelay(); 47 48 // JSONAsynchronousUnpackerDelegate methods. 49 virtual void OnUnpackFinished( 50 const base::DictionaryValue& parsed_json) OVERRIDE; 51 virtual void OnUnpackError(const std::string& error_message) OVERRIDE; 52 53 protected: 54 virtual ~WebResourceService(); 55 56 // For the subclasses to process the result of a fetch. 57 virtual void Unpack(const base::DictionaryValue& parsed_json) = 0; 58 59 PrefService* prefs_; 60 61 private: 62 class UnpackerClient; 63 friend class base::RefCountedThreadSafe<WebResourceService>; 64 65 // net::URLFetcherDelegate implementation: 66 virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE; 67 68 // Schedules a fetch after |delay_ms| milliseconds. 69 void ScheduleFetch(int64 delay_ms); 70 71 // Starts fetching data from the server. 72 void StartFetch(); 73 74 // Set |in_fetch_| to false, clean up temp directories (in the future). 75 void EndFetch(); 76 77 // Implements ResourceRequestAllowedNotifier::Observer. 78 virtual void OnResourceRequestsAllowed() OVERRIDE; 79 80 // Helper class used to tell this service if it's allowed to make network 81 // resource requests. 82 ResourceRequestAllowedNotifier resource_request_allowed_notifier_; 83 84 // The tool that fetches the url data from the server. 85 scoped_ptr<net::URLFetcher> url_fetcher_; 86 87 // The tool that parses and transforms the json data. Weak reference as it 88 // deletes itself once the unpack is done. 89 JSONAsynchronousUnpacker* json_unpacker_; 90 91 // True if we are currently fetching or unpacking data. If we are asked to 92 // start a fetch when we are still fetching resource data, schedule another 93 // one in |cache_update_delay_ms_| time, and silently exit. 94 bool in_fetch_; 95 96 // URL that hosts the web resource. 97 GURL web_resource_server_; 98 99 // Indicates whether we should append locale to the web resource server URL. 100 bool apply_locale_to_url_; 101 102 // Pref name to store the last update's time. 103 const char* last_update_time_pref_name_; 104 105 // Delay on first fetch so we don't interfere with startup. 106 int start_fetch_delay_ms_; 107 108 // Delay between calls to update the web resource cache. This delay may be 109 // different for different builds of Chrome. 110 int cache_update_delay_ms_; 111 112 // So that we can delay our start so as not to affect start-up time; also, 113 // so that we can schedule future cache updates. 114 base::WeakPtrFactory<WebResourceService> weak_ptr_factory_; 115 116 DISALLOW_COPY_AND_ASSIGN(WebResourceService); 117 }; 118 119 #endif // CHROME_BROWSER_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_ 120