Pref service: expose all read-only PrefStores through Mojo

services/preferences/public/cpp/pref_store_client.cc

+// Copyright 2017 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_store_client.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "services/preferences/public/cpp/pref_store_impl.h"
+
+namespace prefs {
+
+PrefStoreClient::PrefStoreClient(mojom::PrefStoreConnectionPtr connection)
+    : initialized_(connection->is_initialized),
+      observer_binding_(this, std::move(connection->observer)) {
+  if (initialized_)
+    OnInitializationCompleted(true);
+  OnPreferencesChanged(std::move(connection->initial_prefs));
+}
+
+PrefStoreClient::~PrefStoreClient() = default;
+
+void PrefStoreClient::AddObserver(PrefStore::Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void PrefStoreClient::RemoveObserver(PrefStore::Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+bool PrefStoreClient::HasObservers() const {
+  return observers_.might_have_observers();
+}
+
+bool PrefStoreClient::IsInitializationComplete() const {
+  return initialized_;
+}
+
+bool PrefStoreClient::GetValue(const std::string& key,
+                               const base::Value** result) const {
+  DCHECK(initialized_);
+  return prefs_.GetValue(key, result);
+}
+
+std::unique_ptr<base::DictionaryValue> PrefStoreClient::GetValues() const {
+  return prefs_.AsDictionaryValue();
+}
+
+void PrefStoreClient::OnPreferencesChanged(
+    std::unique_ptr<base::DictionaryValue> preferences) {
+  for (base::DictionaryValue::Iterator it(*preferences); !it.IsAtEnd();
+       it.Advance()) {
+    bool changed = false;
+    if (it.value().IsType(base::Value::Type::NONE)) {  // Delete
+      if (prefs_.RemoveValue(it.key()))
+        changed = true;
+    } else {
+      if (prefs_.SetValue(it.key(), it.value().CreateDeepCopy()))
+        changed = true;
+    }
+    if (changed) {
+      for (Observer& observer : observers_)
+        observer.OnPrefValueChanged(it.key());
+    }
+  }
+}
+
+void PrefStoreClient::OnInitializationCompleted(bool succeeded) {
+  if (!initialized_) {
+    initialized_ = true;
+    for (Observer& observer : observers_)
+      observer.OnInitializationCompleted(true);
+  }
+}
+
+}  // namespace prefs