Introduce incognito preference settings.

chrome/browser/extensions/extension_pref_value_map.h

+// Copyright (c) 2011 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_
+#pragma once
+
+#include <map>
+#include <set>
+#include <string>
+
+#include "base/time.h"
+#include "chrome/browser/prefs/value_map_pref_store.h"
+
+// Non-persistent data container that is shared by ExtensionPrefStores. All
+// extension pref values (incognito and regular) are stored herein and
+// provided to ExtensionPrefStores.
+//
+// The semantics of the ExtensionPrefValueMap are:
+// - The precedence of extensions is determined by their installation time.
+//   The extension that has been installed later takes higher precedence.
+// - If two extensions set a value for the same preference, the following
+//   rules determine which value becomes effective (visible).
+// - The effective regular extension pref value is determined by the regular
+//   extension pref value of the extension with the highest precedence.
+// - The effective incognito extension pref value is determined by the incognito
+//   extension pref value of the extension with the highest precedence, unless
+//   another extension with higher precedence overrides it with a regular
+//   extension pref value.
+//
+// The following table illustrates the behavior:
+//   A.reg | A.inc | B.reg | B.inc | E.reg | E.inc
+//     1   |   -   |   -   |   -   |   1   |   1
+//     1   |   2   |   -   |   -   |   1   |   2
+//     1   |   -   |   3   |   -   |   3   |   3
+//     1   |   -   |   -   |   4   |   1   |   4
+//     1   |   2   |   3   |   -   |   3   |   3(!)
+//     1   |   2   |   -   |   4   |   1   |   4
+//     1   |   2   |   3   |   4   |   3   |   4
+// A = extension A, B = extension B, E = effective value
+// .reg = regular value
+// .inc = incognito value
+// Extension B has higher precedence than A.
+class ExtensionPrefValueMap {
+ public:
+  // Observer interface for monitoring ExtensionPrefValueMap.
+  class Observer {
+   public:
+    virtual ~Observer() {}
+
+    // Called when the value for the given |key| set by one of the extensions
+    // changes. This does not necessarily mean that the effective value has
+    // changed.
+    virtual void OnPrefValueChanged(const std::string& key) = 0;
+    // Notification about the ExtensionPrefValueMap being fully initialized.
+    virtual void OnInitializationCompleted() = 0;
+    // Called when the ExtensionPrefValueMap is being destroyed. When called,
+    // observers must unsubscribe.
+    virtual void OnExtensionPrefValueMapDestruction() = 0;
+  };
+
+  ExtensionPrefValueMap();
+  virtual ~ExtensionPrefValueMap();
+
+  // Set an extension preference |value| for |key| of extension |ext_id|.
+  // Takes ownership of |value|.
+  // Note that regular extension pref values need to be reported to
+  // incognito and to regular ExtensionPrefStores.
+  // Precondition: the extension must be registered.
+  void SetExtensionPref(const std::string& ext_id,
+                        const std::string& key,
+                        bool incognito,
+                        Value* value);
+
+  // Remove the extension preference value for |key| of extension |ext_id|.
+  // Precondition: the extension must be registered.
+  void RemoveExtensionPref(const std::string& ext_id,
+                           const std::string& key,
+                           bool incognito);
+
+  // Tell the store it's now fully initialized.
+  void NotifyInitializationCompleted();
+
+  // Registers the time when an extension |ext_id| is installed.
+  void RegisterExtension(const std::string& ext_id,
+                         const base::Time& install_time,
+                         bool is_enabled);
+
+  // Deletes all entries related to extension |ext_id|.
+  void UnregisterExtension(const std::string& ext_id);
+
+  // Hides or makes the extension preference values of the specified extension
+  // visible.
+  void SetExtensionState(const std::string& ext_id, bool is_enabled);
+
+  // Adds an observer and notifies it about the currently stored keys.
+  void AddObserver(Observer* observer);

[danno, 2011/01/14 13:05:09]

Perhaps the observer interface should be protected if there is only one client
(class) that should be allowed to use it.

[battre, 2011/01/20 17:59:29]

Discussed this with mnissler and decided not to do this. It creates a tighter
coupling and is syntactically not very nice.

+
+  void RemoveObserver(Observer* observer);
+
+  const Value* GetEffectivePrefValue(const std::string& key,
+                                     bool incognito) const;
+
+ private:
+  struct ExtensionEntry {
+    // Installation time of the extension.
+    base::Time install_time;
+    // Whether extension is enabled in the profile.
+    bool enabled;
+    // Regular preferences.
+    PrefValueMap reg_preferences;
+    // Incognito preferences, empty for regular ExtensionPrefStore.
+    PrefValueMap inc_preferences;
+  };
+
+  typedef std::map<std::string, ExtensionEntry*> ExtensionEntryMap;
+
+  const PrefValueMap* GetExtensionPrefValueMap(const std::string& ext_id,
+                                               bool incognito) const;
+
+  PrefValueMap* GetExtensionPrefValueMap(const std::string& ext_id,
+                                         bool incognito);
+
+  // Returns all keys of pref values that are set by the extension of |entry|,
+  // regardless whether they are set for incognito or regular pref values.
+  void GetExtensionControlledKeys(const ExtensionEntry& entry,
+                                  std::set<std::string>* out) const;
+
+  void NotifyOfDestruction();
+  void NotifyPrefValueChanged(const std::string& key);
+  void NotifyPrefValueChanged(const std::set<std::string>& keys);
+
+  // Mapping of which extension set which preference value. The effective
+  // preferences values (i.e. the ones with the highest precedence)
+  // are stored in ExtensionPrefStores.
+  ExtensionEntryMap entries_;
+
+  ObserverList<Observer, true> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionPrefValueMap);
+};
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_