Split content settings pref related logic into a separate class

components/content_settings/core/browser/content_settings_pref.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_CONTENT_SETTINGS_PREF_H_
+#define COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_CONTENT_SETTINGS_PREF_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/synchronization/lock.h"
+#include "base/threading/thread_checker.h"
+#include "base/values.h"
+#include "components/content_settings/core/browser/content_settings_origin_identifier_value_map.h"
+#include "components/content_settings/core/browser/content_settings_provider.h"
+#include "components/content_settings/core/common/content_settings_pattern.h"
+#include "components/content_settings/core/common/content_settings_types.h"
+
+class PrefService;
+class PrefChangeRegistrar;
+
+namespace base {
+class Clock;
+class DictionaryValue;
+}
+
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
+namespace content_settings {
+
+class RuleIterator;
+
+// Represents a single pref for reading/writing content settings.
+// TODO(raymes): Currently all content settings types are stored in a single
+// instance of one of these. But the intention is that there will be one
+// instance of this class per content settings type.
+class ContentSettingsPref {
+ public:
+  typedef base::Callback<void(const ContentSettingsPattern&,
+                              const ContentSettingsPattern&,
+                              ContentSettingsType,
+                              const std::string&)> NotifyObserversCallback;
+
+  ContentSettingsPref(PrefService* prefs,
+                      PrefChangeRegistrar* registrar,
+                      base::Clock* clock,
+                      bool incognito,
+                      NotifyObserversCallback notify_callback);
+  ~ContentSettingsPref();
+
+  RuleIterator* GetRuleIterator(ContentSettingsType content_type,
+                                const ResourceIdentifier& resource_identifier,
+                                bool incognito) const;
+
+  bool SetWebsiteSetting(const ContentSettingsPattern& primary_pattern,
+                         const ContentSettingsPattern& secondary_pattern,
+                         ContentSettingsType content_type,
+                         const ResourceIdentifier& resource_identifier,
+                         base::Value* value);
+
+  void ClearAllContentSettingsRules(ContentSettingsType content_type);
+
+  void UpdateLastUsage(const ContentSettingsPattern& primary_pattern,
+                       const ContentSettingsPattern& secondary_pattern,
+                       ContentSettingsType content_type);
+
+  base::Time GetLastUsage(const ContentSettingsPattern& primary_pattern,
+                          const ContentSettingsPattern& secondary_pattern,
+                          ContentSettingsType content_type);
+
+  size_t GetNumExceptions();
+
+  void SetClockForTesting(base::Clock* clock);
+ private:
+  friend class DeadlockCheckerThread;  // For testing.
+
+  // Reads all content settings exceptions from the preference and load them
+  // into the |value_map_|. The |value_map_| is cleared first.
+  void ReadContentSettingsFromPref();
+
+  // Callback for changes in the pref with the same name.
+  void OnContentSettingsPatternPairsChanged();
+
+  // Update the preference that stores content settings exceptions and syncs the
+  // value to the obsolete preference. When calling this function, |lock_|
+  // should not be held, since this function will send out notifications of
+  // preference changes.
+  void UpdatePref(
+      const ContentSettingsPattern& primary_pattern,
+      const ContentSettingsPattern& secondary_pattern,
+      ContentSettingsType content_type,
+      const ResourceIdentifier& resource_identifier,
+      const base::Value* value);
+
+  static void CanonicalizeContentSettingsExceptions(
+      base::DictionaryValue* all_settings_dictionary);
+
+  // In the debug mode, asserts that |lock_| is not held by this thread. It's
+  // ok if some other thread holds |lock_|, as long as it will eventually
+  // release it.
+  void AssertLockNotHeld() const;
+
+  // Weak; owned by the Profile and reset in ShutdownOnUIThread.
+  PrefService* prefs_;
+
+  // Owned by the PrefProvider.
+  base::Clock* clock_;
+
+  // Owned by the PrefProvider.
+  PrefChangeRegistrar* registrar_;
+
+  bool is_incognito_;
+
+  // Whether we are currently updating preferences, this is used to ignore
+  // notifications from the preferences service that we triggered ourself.
+  bool updating_preferences_;
+
+  OriginIdentifierValueMap value_map_;
+
+  OriginIdentifierValueMap incognito_value_map_;
+
+  NotifyObserversCallback notify_callback_;
+
+  // Used around accesses to the value map objects to guarantee thread safety.
+  mutable base::Lock lock_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentSettingsPref);
+};
+
+}  // namespace content_settings
+
+#endif  // COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_CONTENT_SETTINGS_PREF_H_