Take out and generalize user prefs overriding from IncognitoUserPrefStore.

Add support for "local" and "global" user preferences where
a "local" preference set in the overlay shadows the "global" preference.

BUG=none
TEST=OverlayUserPrefStoreTest*

Review URL: http://codereview.chromium.org/8515002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109865 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/prefs/incognito_user_pref_store.cc

@@ -3,150 +3,12 @@
 // found in the LICENSE file.
 
 #include "chrome/browser/prefs/incognito_user_pref_store.h"
-
-#include "base/memory/scoped_ptr.h"
-#include "base/values.h"
 #include "chrome/common/pref_names.h"
 
-IncognitoUserPrefStore::IncognitoUserPrefStore(
-    PersistentPrefStore* underlay)
-    : underlay_(underlay) {
-  underlay_->AddObserver(this);
-}
-
-IncognitoUserPrefStore::~IncognitoUserPrefStore() {
-  underlay_->RemoveObserver(this);
-}
-
-bool IncognitoUserPrefStore::IsSetInOverlay(const std::string& key) const {
-  return overlay_.GetValue(key, NULL);
-}
-
-void IncognitoUserPrefStore::AddObserver(PrefStore::Observer* observer) {
-  observers_.AddObserver(observer);
-}
-
-void IncognitoUserPrefStore::RemoveObserver(PrefStore::Observer* observer) {
-  observers_.RemoveObserver(observer);
-}
-
-bool IncognitoUserPrefStore::IsInitializationComplete() const {
-  return underlay_->IsInitializationComplete();
-}
-
-PrefStore::ReadResult IncognitoUserPrefStore::GetValue(
-    const std::string& key,
-    const Value** result) const {
-  // If the |key| shall NOT be stored in the overlay store, there must not
-  // be an entry.
-  DCHECK(ShallBeStoredInOverlay(key) || !overlay_.GetValue(key, NULL));
-
-  if (overlay_.GetValue(key, result))
-    return READ_OK;
-  return underlay_->GetValue(key, result);
-}
-
-PrefStore::ReadResult IncognitoUserPrefStore::GetMutableValue(
-    const std::string& key,
-    Value** result) {
-  if (!ShallBeStoredInOverlay(key))
-    return underlay_->GetMutableValue(key, result);
-
-  if (overlay_.GetValue(key, result))
-    return READ_OK;
-
-  // Try to create copy of underlay if the overlay does not contain a value.
-  Value* underlay_value = NULL;
-  PrefStore::ReadResult read_result =
-      underlay_->GetMutableValue(key, &underlay_value);
-  if (read_result != READ_OK)
-    return read_result;
-
-  *result = underlay_value->DeepCopy();
-  overlay_.SetValue(key, *result);
-  return READ_OK;
-}
-
-void IncognitoUserPrefStore::SetValue(const std::string& key,
-                                      Value* value) {
-  if (!ShallBeStoredInOverlay(key)) {
-    underlay_->SetValue(key, value);
-    return;
-  }
-
-  if (overlay_.SetValue(key, value))
-    ReportValueChanged(key);
-}
-
-void IncognitoUserPrefStore::SetValueSilently(const std::string& key,
-                                              Value* value) {
-  if (!ShallBeStoredInOverlay(key)) {
-    underlay_->SetValueSilently(key, value);
-    return;
-  }
-
-  overlay_.SetValue(key, value);
-}
-
-void IncognitoUserPrefStore::RemoveValue(const std::string& key) {
-  if (!ShallBeStoredInOverlay(key)) {
-    underlay_->RemoveValue(key);
-    return;
-  }
-
-  if (overlay_.RemoveValue(key))
-    ReportValueChanged(key);
-}
-
-bool IncognitoUserPrefStore::ReadOnly() const {
-  return false;
-}
-
-PersistentPrefStore::PrefReadError IncognitoUserPrefStore::ReadPrefs() {
-  // We do not read intentionally.
-  OnInitializationCompleted(true);
-  return PersistentPrefStore::PREF_READ_ERROR_NONE;
-}
-
-void IncognitoUserPrefStore::ReadPrefsAsync(
-    ReadErrorDelegate* error_delegate_raw) {
-  scoped_ptr<ReadErrorDelegate> error_delegate(error_delegate_raw);
-  // We do not read intentionally.
-  OnInitializationCompleted(true);
-}
-
-bool IncognitoUserPrefStore::WritePrefs() {
-  // We do not write our content intentionally.
-  return true;
-}
-
-void IncognitoUserPrefStore::ScheduleWritePrefs() {
-  underlay_->ScheduleWritePrefs();
-  // We do not write our content intentionally.
-}
-
-void IncognitoUserPrefStore::CommitPendingWrite() {
-  underlay_->CommitPendingWrite();
-  // We do not write our content intentionally.
-}
-
-void IncognitoUserPrefStore::ReportValueChanged(const std::string& key) {
-  FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
-}
-
-void IncognitoUserPrefStore::OnPrefValueChanged(const std::string& key) {
-  if (!overlay_.GetValue(key, NULL))
-    ReportValueChanged(key);
-}
-
-void IncognitoUserPrefStore::OnInitializationCompleted(bool succeeded) {
-  FOR_EACH_OBSERVER(PrefStore::Observer, observers_,
-                    OnInitializationCompleted(succeeded));
-}
-
-bool IncognitoUserPrefStore::ShallBeStoredInOverlay(
-    const std::string& key) const {
+IncognitoUserPrefStore::IncognitoUserPrefStore(PersistentPrefStore* underlay)
+    : OverlayUserPrefStore(underlay) {
   // List of keys that cannot be changed in the user prefs file by the incognito
-  // profile:
-  return key == prefs::kBrowserWindowPlacement;
+  // profile.  All preferences that store information about the browsing history
+  // or behavior of the user should have this property.
+  RegisterOverlayProperty(prefs::kBrowserWindowPlacement);
 }

chrome/browser/prefs/incognito_user_pref_store.h

@@ -8,62 +8,13 @@
 
 #include <string>
 
-#include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
-#include "base/observer_list.h"
-#include "chrome/browser/prefs/pref_value_map.h"
-#include "chrome/common/persistent_pref_store.h"
+#include "chrome/browser/prefs/overlay_user_pref_store.h"
 
-// PersistentPrefStore that directs all write operations into an in-memory
-// PrefValueMap. Read operations are first answered by the PrefValueMap.
-// If the PrefValueMap does not contain a value for the requested key,
-// the look-up is passed on to an underlying PersistentPrefStore |underlay_|.
-class IncognitoUserPrefStore : public PersistentPrefStore,
-                               public PrefStore::Observer {
+class IncognitoUserPrefStore : public OverlayUserPrefStore {
  public:
   explicit IncognitoUserPrefStore(PersistentPrefStore* underlay);
-  virtual ~IncognitoUserPrefStore();
-
-  // Returns true if a value has been set for the |key| in this
-  // IncognitoUserPrefStore, i.e. if it potentially overrides a value
-  // from the |underlay_|.
-  virtual bool IsSetInOverlay(const std::string& key) const;
-
-  // Methods of PrefStore.
-  virtual void AddObserver(PrefStore::Observer* observer);
-  virtual void RemoveObserver(PrefStore::Observer* observer);
-  virtual bool IsInitializationComplete() const;
-  virtual ReadResult GetValue(const std::string& key,
-                              const base::Value** result) const;
-
-  // Methods of PersistentPrefStore.
-  virtual ReadResult GetMutableValue(const std::string& key,
-                                     base::Value** result);
-  virtual void SetValue(const std::string& key, base::Value* value);
-  virtual void SetValueSilently(const std::string& key, base::Value* value);
-  virtual void RemoveValue(const std::string& key);
-  virtual bool ReadOnly() const;
-  virtual PrefReadError ReadPrefs();
-  virtual void ReadPrefsAsync(ReadErrorDelegate* delegate);
-  virtual bool WritePrefs();
-  virtual void ScheduleWritePrefs();
-  virtual void CommitPendingWrite();
-  virtual void ReportValueChanged(const std::string& key);
 
  private:
-  // Methods of PrefStore::Observer.
-  virtual void OnPrefValueChanged(const std::string& key);
-  virtual void OnInitializationCompleted(bool succeeded);
-
-  // Returns true if |key| corresponds to a preference that shall be stored in
-  // an in-memory PrefStore that is not persisted to disk. All preferences
-  // that store information about the browsing history or behavior of the user
-  // should have this property.
-  virtual bool ShallBeStoredInOverlay(const std::string& key) const;
-
-  ObserverList<PrefStore::Observer, true> observers_;
-  PrefValueMap overlay_;
-  scoped_refptr<PersistentPrefStore> underlay_;
 
   DISALLOW_COPY_AND_ASSIGN(IncognitoUserPrefStore);
 };

chrome/browser/prefs/overlay_user_pref_store.cc

+// 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.
+
+#include "chrome/browser/prefs/incognito_user_pref_store.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
+
+OverlayUserPrefStore::OverlayUserPrefStore(
+    PersistentPrefStore* underlay)
+    : underlay_(underlay) {
+  underlay_->AddObserver(this);
+}
+
+OverlayUserPrefStore::~OverlayUserPrefStore() {
+  underlay_->RemoveObserver(this);
+}
+
+bool OverlayUserPrefStore::IsSetInOverlay(const std::string& key) const {
+  return overlay_.GetValue(key, NULL);
+}
+
+void OverlayUserPrefStore::AddObserver(PrefStore::Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void OverlayUserPrefStore::RemoveObserver(PrefStore::Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+bool OverlayUserPrefStore::IsInitializationComplete() const {
+  return underlay_->IsInitializationComplete();
+}
+
+PrefStore::ReadResult OverlayUserPrefStore::GetValue(
+    const std::string& key,
+    const Value** result) const {
+  // If the |key| shall NOT be stored in the overlay store, there must not
+  // be an entry.
+  DCHECK(ShallBeStoredInOverlay(key) || !overlay_.GetValue(key, NULL));
+
+  if (overlay_.GetValue(key, result))
+    return READ_OK;
+  return underlay_->GetValue(GetUnderlayKey(key), result);
+}
+
+PrefStore::ReadResult OverlayUserPrefStore::GetMutableValue(
+    const std::string& key,
+    Value** result) {
+  if (!ShallBeStoredInOverlay(key))
+    return underlay_->GetMutableValue(GetUnderlayKey(key), result);
+
+  if (overlay_.GetValue(key, result))
+    return READ_OK;
+
+  // Try to create copy of underlay if the overlay does not contain a value.
+  Value* underlay_value = NULL;
+  PrefStore::ReadResult read_result =
+      underlay_->GetMutableValue(GetUnderlayKey(key), &underlay_value);
+  if (read_result != READ_OK)
+    return read_result;
+
+  *result = underlay_value->DeepCopy();
+  overlay_.SetValue(key, *result);
+  return READ_OK;
+}
+
+void OverlayUserPrefStore::SetValue(const std::string& key,
+                                      Value* value) {
+  if (!ShallBeStoredInOverlay(key)) {
+    underlay_->SetValue(GetUnderlayKey(key), value);
+    return;
+  }
+
+  if (overlay_.SetValue(key, value))
+    ReportValueChanged(key);
+}
+
+void OverlayUserPrefStore::SetValueSilently(const std::string& key,
+                                              Value* value) {
+  if (!ShallBeStoredInOverlay(key)) {
+    underlay_->SetValueSilently(GetUnderlayKey(key), value);
+    return;
+  }
+
+  overlay_.SetValue(key, value);
+}
+
+void OverlayUserPrefStore::RemoveValue(const std::string& key) {
+  if (!ShallBeStoredInOverlay(key)) {
+    underlay_->RemoveValue(GetUnderlayKey(key));
+    return;
+  }
+
+  if (overlay_.RemoveValue(key))
+    ReportValueChanged(key);
+}
+
+bool OverlayUserPrefStore::ReadOnly() const {
+  return false;
+}
+
+PersistentPrefStore::PrefReadError OverlayUserPrefStore::ReadPrefs() {
+  // We do not read intentionally.
+  OnInitializationCompleted(true);
+  return PersistentPrefStore::PREF_READ_ERROR_NONE;
+}
+
+void OverlayUserPrefStore::ReadPrefsAsync(
+    ReadErrorDelegate* error_delegate_raw) {
+  scoped_ptr<ReadErrorDelegate> error_delegate(error_delegate_raw);
+  // We do not read intentionally.
+  OnInitializationCompleted(true);
+}
+
+bool OverlayUserPrefStore::WritePrefs() {
+  // We do not write our content intentionally.
+  return true;
+}
+
+void OverlayUserPrefStore::ScheduleWritePrefs() {
+  underlay_->ScheduleWritePrefs();
+  // We do not write our content intentionally.
+}
+
+void OverlayUserPrefStore::CommitPendingWrite() {
+  underlay_->CommitPendingWrite();
+  // We do not write our content intentionally.
+}
+
+void OverlayUserPrefStore::ReportValueChanged(const std::string& key) {
+  FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
+}
+
+void OverlayUserPrefStore::RegisterOverlayProperty(const std::string& key) {
+  RegisterOverlayProperty(key, key);
+}
+
+void OverlayUserPrefStore::RegisterOverlayProperty(
+    const std::string& overlay_key,
+    const std::string& underlay_key) {
+  DCHECK(!overlay_key.empty()) << "Overlay key is empty";
+  DCHECK(overlay_to_underlay_names_map_.find(overlay_key) ==
+         overlay_to_underlay_names_map_.end()) <<
+      "Overlay key already registered";
+  DCHECK(!underlay_key.empty()) << "Underlay key is empty";
+  DCHECK(underlay_to_overlay_names_map_.find(underlay_key) ==
+         underlay_to_overlay_names_map_.end()) <<
+      "Underlay key already registered";
+  overlay_to_underlay_names_map_[overlay_key] = underlay_key;
+  underlay_to_overlay_names_map_[underlay_key] = overlay_key;
+}
+
+void OverlayUserPrefStore::OnPrefValueChanged(const std::string& key) {
+  if (!overlay_.GetValue(GetOverlayKey(key), NULL))
+    ReportValueChanged(GetOverlayKey(key));
+}
+
+void OverlayUserPrefStore::OnInitializationCompleted(bool succeeded) {
+  FOR_EACH_OBSERVER(PrefStore::Observer, observers_,
+                    OnInitializationCompleted(succeeded));
+}
+
+const std::string& OverlayUserPrefStore::GetOverlayKey(
+    const std::string& underlay_key) const {
+  NamesMap::const_iterator i =
+      underlay_to_overlay_names_map_.find(underlay_key);
+  return i != underlay_to_overlay_names_map_.end() ? i->second : underlay_key;
+}
+
+const std::string& OverlayUserPrefStore::GetUnderlayKey(
+    const std::string& overlay_key) const {
+  NamesMap::const_iterator i =
+      overlay_to_underlay_names_map_.find(overlay_key);
+  return i != overlay_to_underlay_names_map_.end() ? i->second : overlay_key;
+}
+
+bool OverlayUserPrefStore::ShallBeStoredInOverlay(
+    const std::string& key) const {
+  return overlay_to_underlay_names_map_.find(key) !=
+      overlay_to_underlay_names_map_.end();
+}

chrome/browser/prefs/overlay_user_pref_store.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_PREFS_OVERLAY_USER_PREF_STORE_H_
+#define CHROME_BROWSER_PREFS_OVERLAY_USER_PREF_STORE_H_
+#pragma once
+
+#include <map>
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
+#include "chrome/browser/prefs/pref_value_map.h"
+#include "chrome/common/persistent_pref_store.h"
+
+// PersistentPrefStore that directs all write operations into an in-memory
+// PrefValueMap. Read operations are first answered by the PrefValueMap.
+// If the PrefValueMap does not contain a value for the requested key,
+// the look-up is passed on to an underlying PersistentPrefStore |underlay_|.
+class OverlayUserPrefStore : public PersistentPrefStore,
+                             public PrefStore::Observer {
+ public:
+  explicit OverlayUserPrefStore(PersistentPrefStore* underlay);
+  virtual ~OverlayUserPrefStore();
+
+  // Returns true if a value has been set for the |key| in this
+  // OverlayUserPrefStore, i.e. if it potentially overrides a value
+  // from the |underlay_|.
+  virtual bool IsSetInOverlay(const std::string& key) const;
+
+  // Methods of PrefStore.
+  virtual void AddObserver(PrefStore::Observer* observer);
+  virtual void RemoveObserver(PrefStore::Observer* observer);
+  virtual bool IsInitializationComplete() const;
+  virtual ReadResult GetValue(const std::string& key,
+                              const base::Value** result) const;
+
+  // Methods of PersistentPrefStore.
+  virtual ReadResult GetMutableValue(const std::string& key,
+                                     base::Value** result);
+  virtual void SetValue(const std::string& key, base::Value* value);
+  virtual void SetValueSilently(const std::string& key, base::Value* value);
+  virtual void RemoveValue(const std::string& key);
+  virtual bool ReadOnly() const;
+  virtual PrefReadError ReadPrefs();
+  virtual void ReadPrefsAsync(ReadErrorDelegate* delegate);
+  virtual bool WritePrefs();
+  virtual void ScheduleWritePrefs();
+  virtual void CommitPendingWrite();
+  virtual void ReportValueChanged(const std::string& key);
+
+ protected:
+  void RegisterOverlayProperty(const std::string& key);
+  void RegisterOverlayProperty(const std::string& overlay_key,
+                               const std::string& underlay_key);
+
+ private:
+  friend class OverlayUserPrefStoreTest;
+
+  typedef std::map<std::string, std::string> NamesMap;
+
+  // Methods of PrefStore::Observer.
+  virtual void OnPrefValueChanged(const std::string& key);
+  virtual void OnInitializationCompleted(bool succeeded);
+
+  const std::string& GetOverlayKey(const std::string& underlay_key) const;
+  const std::string& GetUnderlayKey(const std::string& overlay_key) const;
+
+  // Returns true if |key| corresponds to a preference that shall be stored in
+  // an in-memory PrefStore that is not persisted to disk.
+  bool ShallBeStoredInOverlay(const std::string& key) const;
+
+  ObserverList<PrefStore::Observer, true> observers_;
+  PrefValueMap overlay_;
+  scoped_refptr<PersistentPrefStore> underlay_;
+  NamesMap overlay_to_underlay_names_map_;
+  NamesMap underlay_to_overlay_names_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(OverlayUserPrefStore);
+};
+
+#endif  // CHROME_BROWSER_PREFS_OVERLAY_USER_PREF_STORE_H_

chrome/chrome_browser.gypi

@@ -1827,6 +1827,8 @@
         'browser/prefs/incognito_mode_prefs.h',
         'browser/prefs/incognito_user_pref_store.cc',
         'browser/prefs/incognito_user_pref_store.h',
+        'browser/prefs/overlay_user_pref_store.cc',
+        'browser/prefs/overlay_user_pref_store.h',
         'browser/prefs/pref_change_registrar.cc',
         'browser/prefs/pref_change_registrar.h',
         'browser/prefs/pref_member.cc',

chrome/chrome_tests.gypi

@@ -1503,7 +1503,7 @@
         'browser/preferences_mock_mac.h',
         'browser/prefs/command_line_pref_store_unittest.cc',
         'browser/prefs/incognito_mode_prefs_unittest.cc',
-        'browser/prefs/incognito_user_pref_store_unittest.cc',
+        'browser/prefs/overlay_user_pref_store_unittest.cc',
         'browser/prefs/pref_change_registrar_unittest.cc',
         'browser/prefs/pref_member_unittest.cc',
         'browser/prefs/pref_model_associator_unittest.cc',