Split the aggregate dictionary of content settings exceptions into per-type dictionaries

components/content_settings/core/browser/content_settings_pref_provider.h

 // Copyright (c) 2012 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_PROVIDER_H_
 #define COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_CONTENT_SETTINGS_PREF_PROVIDER_H_
 
 // A content settings provider that takes its settings out of the pref service.
 
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/memory/scoped_vector.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "components/content_settings/core/browser/content_settings_observable_provider.h"
 #include "components/content_settings/core/browser/content_settings_utils.h"
 
 class PrefService;
 
 namespace base {
 class Clock;
 class DictionaryValue;
 }
@@ skipping 40 matching lines @@
                           ContentSettingsType content_type);
 
   void Notify(const ContentSettingsPattern& primary_pattern,
               const ContentSettingsPattern& secondary_pattern,
               ContentSettingsType content_type,
               const std::string& resource_identifier);
 
   // Gains ownership of |clock|.
   void SetClockForTesting(scoped_ptr<base::Clock> clock);
 
-  ContentSettingsPref* content_settings_pref() {
-    return content_settings_pref_.get();
-  }
+ private:
+  friend class DeadlockCheckerThread;  // For testing.
 
- private:
   // Migrate the old media setting into new mic/camera content settings.
   void MigrateObsoleteMediaContentSetting();
 
+  // Migrate the settings from the old aggregate dictionary into the new format.
+  void MigrateAllExceptions();
+
+  // Writes the contents of the old aggregate dictionary preferences into
+  // separate dictionaries for content types. If |syncable_only| is true,
+  // only syncable content types will be written.
+  void WriteSettingsToNewPreferences(bool syncable_only);
+
   // Weak; owned by the Profile and reset in ShutdownOnUIThread.
   PrefService* prefs_;
 
   // Can be set for testing.
   scoped_ptr<base::Clock> clock_;
 
   bool is_incognito_;
 
   PrefChangeRegistrar pref_change_registrar_;
 
-  scoped_ptr<ContentSettingsPref> content_settings_pref_;
+  ScopedVector<ContentSettingsPref> content_settings_prefs_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefProvider);
+
+  bool TestAllLocks() const;
+
+  // All functionality regarding reading and writing of preferences has been
+  // moved to |ContentSettingsPref|, which manages one content type per
+  // instance. However, for backward compatibility, we need to be able to write
+  // to the old and deprecated aggregate dictionary preference which maintains
+  // all content types. Therefore, |ContentSettingsPrefProvider| must still
+  // retain some of the functionality of |ContentSettingsPref|. The following
+  // attributes and methods serve this purpose.
+  // TODO(msramek): Remove this migration code after two stable releases.
+  struct ContentSettingsPrefEntry {
+    ContentSettingsPrefEntry(const ContentSettingsPattern primary_pattern,
+                             const ContentSettingsPattern secondary_pattern,
+                             const ResourceIdentifier resource_identifier,
+                             base::Value* value);
+    ContentSettingsPrefEntry(const ContentSettingsPrefEntry& entry);
+    ContentSettingsPrefEntry& operator=(const ContentSettingsPrefEntry& entry);
+    ~ContentSettingsPrefEntry();
+
+    ContentSettingsPattern primary_pattern;
+    ContentSettingsPattern secondary_pattern;
+    ResourceIdentifier resource_identifier;
+    scoped_ptr<base::Value> value;
+  };
+
+  ScopedVector<ContentSettingsPrefEntry>

[msramek, 2015/04/01 09:34:26]

ScopedVector is the best solution here, which I didn't know about until
recently. However, we cannot have a map of ScopedVectors, and we don't have a
ScopedMap. To prevent adding further boilerplate code of copy constructors,
let's just have a simple array here. It's not a good practice to define a
const-size array type, so let's just have it as an attribute. The only access to
this map was protected by a lock anyway, so we don't need more than one.

+      pref_entry_map_[CONTENT_SETTINGS_NUM_TYPES];
+
+  void ClearPrefEntryMap();
+
+  mutable base::Lock old_lock_;
+
+  bool updating_old_preferences_;
+
+  void OnOldContentSettingsPatternPairsChanged();
+
+  void ReadContentSettingsFromOldPref();
+
+  base::ThreadChecker thread_checker_;
 };
 
 }  // namespace content_settings
 
 #endif  // COMPONENTS_CONTENT_SETTINGS_CORE_BROWSER_CONTENT_SETTINGS_PREF_PROVIDER_H_