chrome/browser/extensions/api/preference/chrome_direct_setting_api.cc

   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 #include "chrome/browser/extensions/api/preference/chrome_direct_setting_api.h"
   6
   7 #include "base/bind.h"
   8 #include "base/containers/hash_tables.h"
   9 #include "base/lazy_instance.h"
  10 #include "base/prefs/pref_change_registrar.h"
  11 #include "base/prefs/pref_service.h"
  12 #include "base/strings/stringprintf.h"
  13 #include "chrome/browser/extensions/api/preference/preference_api_constants.h"
  14 #include "chrome/browser/profiles/profile.h"
  15 #include "extensions/browser/extension_registry.h"
  16
  17 namespace extensions {
  18 namespace chromedirectsetting {
  19
  20 const char kOnPrefChangeFormat[] =
  21     "types.private.ChromeDirectSetting.%s.onChange";
  22
  23 class PreferenceWhitelist {
  24  public:
  25   PreferenceWhitelist() {
  26     // Note: DO NOT add any setting here that does not have a UI element in
  27     // chrome://settings unless you write a component extension that is always
  28     // installed. Otherwise, users may install your extension, the extension may
  29     // toggle settings, and after the extension has been disabled/uninstalled
  30     // the toggled setting remains in place. See http://crbug.com/164227#c157 .
  31     whitelist_.insert("googlegeolocationaccess.enabled");
  32     // The following settings need to be checked and probably removed. See
  33     // http://crbug.com/164227#c157 .
  34     whitelist_.insert("data_reduction.update_daily_lengths");
  35     whitelist_.insert("easy_unlock.proximity_required");
  36   }
  37
  38   ~PreferenceWhitelist() {}
  39
  40   bool IsPreferenceOnWhitelist(const std::string& pref_key){
  41     return whitelist_.find(pref_key) != whitelist_.end();
  42   }
  43
  44   void RegisterEventListeners(
  45       Profile* profile,
  46       EventRouter::Observer* observer) {
  47     for (base::hash_set<std::string>::iterator iter = whitelist_.begin();
  48          iter != whitelist_.end();
  49          iter++) {
  50       std::string event_name = base::StringPrintf(
  51           kOnPrefChangeFormat,
  52           (*iter).c_str());
  53       EventRouter::Get(profile)->RegisterObserver(observer, event_name);
  54     }
  55   }
  56
  57   void RegisterPropertyListeners(
  58       Profile* profile,
  59       PrefChangeRegistrar* registrar,
  60       const base::Callback<void(const std::string&)>& callback) {
  61     for (base::hash_set<std::string>::iterator iter = whitelist_.begin();
  62          iter != whitelist_.end();
  63          iter++) {
  64       const char* pref_key = (*iter).c_str();
  65       std::string event_name = base::StringPrintf(
  66           kOnPrefChangeFormat,
  67           pref_key);
  68       registrar->Add(pref_key, callback);
  69     }
  70   }
  71
  72  private:
  73   base::hash_set<std::string> whitelist_;
  74
  75   DISALLOW_COPY_AND_ASSIGN(PreferenceWhitelist);
  76 };
  77
  78 base::LazyInstance<PreferenceWhitelist> preference_whitelist =
  79     LAZY_INSTANCE_INITIALIZER;
  80
  81 static base::LazyInstance<
  82     BrowserContextKeyedAPIFactory<ChromeDirectSettingAPI> > g_factory =
  83     LAZY_INSTANCE_INITIALIZER;
  84
  85 ChromeDirectSettingAPI::ChromeDirectSettingAPI(content::BrowserContext* context)
  86     : profile_(Profile::FromBrowserContext(context)) {
  87   preference_whitelist.Get().RegisterEventListeners(profile_, this);
  88 }
  89
  90 ChromeDirectSettingAPI::~ChromeDirectSettingAPI() {}
  91
  92 // KeyedService implementation.
  93 void ChromeDirectSettingAPI::Shutdown() {}
  94
  95 // BrowserContextKeyedAPI implementation.
  96 BrowserContextKeyedAPIFactory<ChromeDirectSettingAPI>*
  97 ChromeDirectSettingAPI::GetFactoryInstance() {
  98   return g_factory.Pointer();
  99 }
 100
 101 // EventRouter::Observer implementation.
 102 void ChromeDirectSettingAPI::OnListenerAdded(const EventListenerInfo& details) {
 103   EventRouter::Get(profile_)->UnregisterObserver(this);
 104   registrar_.Init(profile_->GetPrefs());
 105   preference_whitelist.Get().RegisterPropertyListeners(
 106       profile_,
 107       &registrar_,
 108       base::Bind(&ChromeDirectSettingAPI::OnPrefChanged,
 109                  base::Unretained(this),
 110                  registrar_.prefs()));
 111 }
 112
 113 bool ChromeDirectSettingAPI::IsPreferenceOnWhitelist(
 114     const std::string& pref_key) {
 115   return preference_whitelist.Get().IsPreferenceOnWhitelist(pref_key);
 116 }
 117
 118 ChromeDirectSettingAPI* ChromeDirectSettingAPI::Get(
 119     content::BrowserContext* context) {
 120   return BrowserContextKeyedAPIFactory<ChromeDirectSettingAPI>::Get(context);
 121 }
 122
 123 // BrowserContextKeyedAPI implementation.
 124 const char* ChromeDirectSettingAPI::service_name() {
 125   return "ChromeDirectSettingAPI";
 126 }
 127
 128 void ChromeDirectSettingAPI::OnPrefChanged(
 129     PrefService* pref_service, const std::string& pref_key) {
 130   std::string event_name = base::StringPrintf(kOnPrefChangeFormat,
 131                                               pref_key.c_str());
 132   EventRouter* router = EventRouter::Get(profile_);
 133   if (router && router->HasEventListener(event_name)) {
 134     const PrefService::Preference* preference =
 135         profile_->GetPrefs()->FindPreference(pref_key.c_str());
 136     const base::Value* value = preference->GetValue();
 137
 138     scoped_ptr<base::DictionaryValue> result(new base::DictionaryValue);
 139     result->Set(preference_api_constants::kValue, value->DeepCopy());
 140     base::ListValue args;
 141     args.Append(result.release());
 142
 143     for (const scoped_refptr<const extensions::Extension>& extension :
 144          ExtensionRegistry::Get(profile_)->enabled_extensions()) {
 145       const std::string& extension_id = extension->id();
 146       if (router->ExtensionHasEventListener(extension_id, event_name)) {
 147         scoped_ptr<base::ListValue> args_copy(args.DeepCopy());
 148         // TODO(kalman): Have a histogram value for each pref type.
 149         // This isn't so important for the current use case of these
 150         // histograms, which is to track which event types are waking up event
 151         // pages, or which are delivered to persistent background pages. Simply
 152         // "a setting changed" is enough detail for that. However if we try to
 153         // use these histograms for any fine-grained logic (like removing the
 154         // string event name altogether), or if we discover this event is
 155         // firing a lot and want to understand that better, then this will need
 156         // to change.
 157         events::HistogramValue histogram_value =
 158             events::TYPES_PRIVATE_CHROME_DIRECT_SETTING_ON_CHANGE;
 159         scoped_ptr<Event> event(
 160             new Event(histogram_value, event_name, args_copy.Pass()));
 161         router->DispatchEventToExtension(extension_id, event.Pass());
 162       }
 163     }
 164   }
 165 }
 166
 167 }  // namespace chromedirectsetting
 168 }  // namespace extensions