Mojom interface for Preferences

services/preferences/public/cpp/pref_observer_store.cc

+// Copyright 2016 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 "services/preferences/public/cpp/pref_observer_store.h"
+
+#include "base/values.h"
+#include "mojo/common/common_custom_types.mojom.h"
+#include "mojo/public/cpp/bindings/array.h"
+#include "services/shell/public/cpp/connector.h"
+
+PrefObserverStore::PrefObserverStore(
+    prefs::mojom::PreferenceManagerPtr prefs_manager_ptr)
+    : prefs_binding_(this),
+      prefs_manager_ptr_(std::move(prefs_manager_ptr)),
+      prefs_manager_(nullptr),
+      initialized_(false) {
+  prefs_manager_ = prefs_manager_ptr_.get();
+}
+
+void PrefObserverStore::Init(const std::set<std::string>& keys) {
+  DCHECK(!initialized_);
+  DCHECK(prefs_manager_);
+  keys_ = keys;
+
+  std::vector<std::string> pref_array;
+  std::copy(keys_.begin(), keys_.end(), std::back_inserter(pref_array));
+  prefs_manager_->AddObserver(std::move(pref_array),
+                              prefs_binding_.CreateInterfacePtrAndBind());
+}
+
+bool PrefObserverStore::GetValue(const std::string& key,
+                                 const base::Value** value) const {
+  DCHECK(initialized_);
+  DCHECK(keys_.find(key) != keys_.end());
+
+  return ValueMapPrefStore::GetValue(key, value);
+}
+
+void PrefObserverStore::SetValue(const std::string& key,
+                                 std::unique_ptr<base::Value> value,
+                                 uint32_t flags) {
+  DCHECK(keys_.find(key) != keys_.end());
+
+  SetValueOnPreferenceManager(key, value.get());

[sadrul, 2016/10/06 14:09:41]

It'd be nice to not notify the server if the value doesn't actually change.
(e.g.
https://cs.chromium.org/chromium/src/components/prefs/value_map_pref_store.cc...
doesn't notify the observers if the value didn't change). Let's leave a TODO
here.

[jonross, 2016/10/06 21:36:20]

Done.

+  ValueMapPrefStore::SetValue(key, std::move(value), flags);
+}
+
+void PrefObserverStore::RemoveValue(const std::string& key, uint32_t flags) {
+  // TODO(jonross): add preference removal to preferences.mojom
+  NOTIMPLEMENTED();
+}
+
+bool PrefObserverStore::GetMutableValue(const std::string& key,
+                                        base::Value** value) {
+  DCHECK(initialized_);
+  DCHECK(keys_.find(key) != keys_.end());
+
+  // TODO(jonross): add unittests once a mutable class of base::Value is used.
+  // Such as base::DictionaryValue.
+  return ValueMapPrefStore::GetMutableValue(key, value);
+}
+
+void PrefObserverStore::ReportValueChanged(const std::string& key,
+                                           uint32_t flags) {
+  ValueMapPrefStore::ReportValueChanged(key, flags);
+}
+
+void PrefObserverStore::SetValueSilently(const std::string& key,
+                                         std::unique_ptr<base::Value> value,
+                                         uint32_t flags) {
+  SetValueOnPreferenceManager(key, value.get());
+  ValueMapPrefStore::SetValueSilently(key, std::move(value), flags);
+}
+
+PrefObserverStore::~PrefObserverStore() {}
+
+void PrefObserverStore::SetValueOnPreferenceManager(const std::string& key,
+                                                    base::Value* value) {
+  if (keys_.find(key) == keys_.end())
+    return;
+
+  base::DictionaryValue prefs;
+  prefs.Set(key, value->CreateDeepCopy());
+  prefs_manager_->SetPreferences(prefs);
+}
+
+void PrefObserverStore::OnPreferencesChanged(
+    const base::DictionaryValue& preferences) {
+  for (base::DictionaryValue::Iterator it(preferences); !it.IsAtEnd();
+       it.Advance()) {
+    if (keys_.find(it.key()) == keys_.end())
+      continue;
+    ValueMapPrefStore::SetValue(it.key(), it.value().CreateDeepCopy(), 0);

[sadrul, 2016/10/06 14:09:41]

Add a comment here that we deliberately call the parent here to avoid notifying
the server again.

[jonross, 2016/10/06 21:36:20]

Done.

+  }
+
+  if (!initialized_) {
+    initialized_ = true;
+    NotifyInitializationCompleted();
+  }
+}