Pref service: add persistent pref store frontend and backend.

services/preferences/public/cpp/persistent_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/persistent_pref_store_client.h"
+
+#include <utility>
+
+#include "base/values.h"
+
+namespace prefs {
+
+PersistentPrefStoreClient::PersistentPrefStoreClient(
+    mojom::PersistentPrefStoreConnectorPtr connector)
+    : connector_(std::move(connector)) {}
+
+void PersistentPrefStoreClient::SetValue(const std::string& key,
+                                         std::unique_ptr<base::Value> value,
+                                         uint32_t flags) {
+  base::Value* old_value = nullptr;
+  GetMutableValues().Get(key, &old_value);
+  if (!old_value || !value->Equals(old_value)) {
+    GetMutableValues().Set(key, std::move(value));
+    ReportValueChanged(key, flags);
+  }
+}
+
+void PersistentPrefStoreClient::RemoveValue(const std::string& key,
+                                            uint32_t flags) {
+  if (GetMutableValues().RemovePath(key, nullptr))
+    ReportValueChanged(key, flags);
+}
+
+bool PersistentPrefStoreClient::GetMutableValue(const std::string& key,
+                                                base::Value** result) {
+  return GetMutableValues().Get(key, result);
+}
+
+void PersistentPrefStoreClient::ReportValueChanged(const std::string& key,
+                                                   uint32_t flags) {
+  DCHECK(pref_store_);
+  const base::Value* local_value = nullptr;
+  GetMutableValues().Get(key, &local_value);
+  pref_store_->SetValue(
+      key, local_value ? local_value->CreateDeepCopy() : nullptr, flags);
+  ReportPrefValueChanged(key);
+}
+
+void PersistentPrefStoreClient::SetValueSilently(
+    const std::string& key,
+    std::unique_ptr<base::Value> value,
+    uint32_t flags) {
+  DCHECK(pref_store_);
+  pref_store_->SetValue(key, value->CreateDeepCopy(), flags);
+  GetMutableValues().Set(key, std::move(value));
+}
+
+bool PersistentPrefStoreClient::ReadOnly() const {
+  return read_only_;
+}
+
+PersistentPrefStore::PrefReadError PersistentPrefStoreClient::GetReadError()
+    const {
+  return read_error_;
+}
+
+PersistentPrefStore::PrefReadError PersistentPrefStoreClient::ReadPrefs() {
+  PrefReadError read_error = PrefReadError::PREF_READ_ERROR_NONE;
+  bool read_only = false;
+  std::unique_ptr<base::DictionaryValue> local_prefs;
+  mojom::PersistentPrefStorePtr pref_store;
+  mojom::PrefStoreObserverRequest observer_request;
+  if (!connector_->Connect(&read_error, &read_only, &local_prefs, &pref_store,
+                           &observer_request)) {
+    NOTREACHED();
+  }
+
+  OnCreateComplete(read_error, read_only, std::move(local_prefs),
+                   std::move(pref_store), std::move(observer_request));
+  return read_error_;
+}
+
+void PersistentPrefStoreClient::ReadPrefsAsync(
+    ReadErrorDelegate* error_delegate) {
+  error_delegate_.reset(error_delegate);
+  connector_->Connect(base::Bind(&PersistentPrefStoreClient::OnCreateComplete,
+                                 base::Unretained(this)));
+}
+
+void PersistentPrefStoreClient::CommitPendingWrite() {
+  DCHECK(pref_store_);
+  pref_store_->CommitPendingWrite();
+}
+
+void PersistentPrefStoreClient::SchedulePendingLossyWrites() {
+  DCHECK(pref_store_);
+  return pref_store_->SchedulePendingLossyWrites();
+}
+
+void PersistentPrefStoreClient::ClearMutableValues() {
+  DCHECK(pref_store_);
+  return pref_store_->ClearMutableValues();
+}
+
+PersistentPrefStoreClient::~PersistentPrefStoreClient() {
+  if (!pref_store_)
+    return;
+
+  pref_store_->CommitPendingWrite();
+}
+
+void PersistentPrefStoreClient::OnCreateComplete(
+    PrefReadError read_error,
+    bool read_only,
+    std::unique_ptr<base::DictionaryValue> cached_prefs,
+    mojom::PersistentPrefStorePtr pref_store,
+    mojom::PrefStoreObserverRequest observer_request) {
+  connector_.reset();
+  read_error_ = read_error;
+  read_only_ = read_only;
+  pref_store_ = std::move(pref_store);
+  if (error_delegate_ && read_error_ != PREF_READ_ERROR_NONE)
+    error_delegate_->OnError(read_error_);
+  error_delegate_.reset();
+
+  Init(std::move(cached_prefs), true, std::move(observer_request));
+}
+
+}  // namespace prefs