Pref service: Add a ScopedDictionaryPrefUpdate to track value changes.

services/preferences/public/cpp/scoped_pref_update.cc

Index: services/preferences/public/cpp/scoped_pref_update.cc
diff --git a/services/preferences/public/cpp/scoped_pref_update.cc b/services/preferences/public/cpp/scoped_pref_update.cc
new file mode 100644
index 0000000000000000000000000000000000000000..433ecd8724e0f9afca822c2e958c4c00b8592bbc
--- /dev/null
+++ b/services/preferences/public/cpp/scoped_pref_update.cc
@@ -0,0 +1,385 @@
+// 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/scoped_pref_update.h"
+
+#include <algorithm>
+#include <utility>
+
+#include "base/memory/ptr_util.h"
+#include "base/strings/string_split.h"
+#include "components/prefs/pref_service.h"
+
+namespace prefs {
+
+ScopedDictionaryPrefUpdate::ScopedDictionaryPrefUpdate(PrefService* service,
+                                                       base::StringPiece path)
+    : service_(service), path_(path.as_string()) {
+  base::DictionaryValue* value = static_cast<base::DictionaryValue*>(
+      service_->GetMutableUserPref(path_, base::Value::Type::DICTIONARY));
+  value_ = Insert(base::WrapUnique(
+      new DictionaryValueUpdate(this, value, std::vector<std::string>())));
+}
+
+ScopedDictionaryPrefUpdate::~ScopedDictionaryPrefUpdate() {
+  if (value_)
+    Notify();
+}
+
+DictionaryValueUpdate* ScopedDictionaryPrefUpdate::Get() {
+  return value_;
+}
+
+DictionaryValueUpdate* ScopedDictionaryPrefUpdate::operator->() {
+  return Get();
+}
+
+void ScopedDictionaryPrefUpdate::Notify() {
+  DCHECK(value_);
+  if (!updated_paths_.empty())
+    service_->ReportUserPrefChanged(path_, std::move(updated_paths_));
+  value_ = nullptr;
+  updates_.clear();
+}
+
+void ScopedDictionaryPrefUpdate::RecordPath(
+    const std::vector<std::string>& path) {
+  updated_paths_.insert(std::move(path));
+}
+
+DictionaryValueUpdate* ScopedDictionaryPrefUpdate::Insert(
+    std::unique_ptr<DictionaryValueUpdate> dictionary_value_update) {
+  updates_.push_back(std::move(dictionary_value_update));
+  return updates_.back().get();
+}
+
+DictionaryValueUpdate::DictionaryValueUpdate(ScopedDictionaryPrefUpdate* update,
+                                             base::DictionaryValue* value,
+                                             std::vector<std::string> path)
+    : update_(update), value_(value), path_(std::move(path)) {}
+
+DictionaryValueUpdate::~DictionaryValueUpdate() = default;
+
+bool DictionaryValueUpdate::HasKey(base::StringPiece key) const {
+  return value_->HasKey(key);
+}
+
+size_t DictionaryValueUpdate::size() const {
+  return value_->size();
+}
+
+bool DictionaryValueUpdate::empty() const {
+  return value_->empty();
+}
+
+void DictionaryValueUpdate::Clear() {
+  if (empty())
+    return;
+
+  RecordSplitPath(std::vector<base::StringPiece>());
+  value_->Clear();
+}
+
+void DictionaryValueUpdate::Set(base::StringPiece path,
+                                std::unique_ptr<base::Value> in_value) {
+  const base::Value* old_value = nullptr;
+  if (value_->Get(path, &old_value) && *old_value == *in_value)
+    return;
+
+  RecordPath(path);
+  value_->Set(path, std::move(in_value));
+}
+
+void DictionaryValueUpdate::SetBoolean(base::StringPiece path, bool in_value) {
+  Set(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetInteger(base::StringPiece path, int in_value) {
+  Set(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetDouble(base::StringPiece path, double in_value) {
+  Set(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetString(base::StringPiece path,
+                                      base::StringPiece in_value) {
+  Set(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetString(base::StringPiece path,
+                                      const base::string16& in_value) {
+  Set(path, base::MakeUnique<base::Value>(in_value));
+}
+
+DictionaryValueUpdate* DictionaryValueUpdate::SetDictionary(
+    base::StringPiece path,
+    std::unique_ptr<base::DictionaryValue> in_value) {
+  RecordPath(path);
+  base::DictionaryValue* dictionary_value = in_value.get();
+  value_->Set(path, std::move(in_value));
+
+  return update_->Insert(base::WrapUnique(new DictionaryValueUpdate(
+      update_, dictionary_value, ConcatPath(path_, path))));
+}
+
+void DictionaryValueUpdate::SetWithoutPathExpansion(
+    base::StringPiece key,
+    std::unique_ptr<base::Value> in_value) {
+  const base::Value* old_value = nullptr;
+  if (value_->GetWithoutPathExpansion(key, &old_value) &&
+      *old_value == *in_value) {
+    return;
+  }
+  RecordKey(key);
+  value_->SetWithoutPathExpansion(key, std::move(in_value));
+}
+
+void DictionaryValueUpdate::SetBooleanWithoutPathExpansion(
+    base::StringPiece path,
+    bool in_value) {
+  SetWithoutPathExpansion(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetIntegerWithoutPathExpansion(
+    base::StringPiece path,
+    int in_value) {
+  SetWithoutPathExpansion(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetDoubleWithoutPathExpansion(
+    base::StringPiece path,
+    double in_value) {
+  SetWithoutPathExpansion(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetStringWithoutPathExpansion(
+    base::StringPiece path,
+    base::StringPiece in_value) {
+  SetWithoutPathExpansion(path, base::MakeUnique<base::Value>(in_value));
+}
+
+void DictionaryValueUpdate::SetStringWithoutPathExpansion(
+    base::StringPiece path,
+    const base::string16& in_value) {
+  SetWithoutPathExpansion(path, base::MakeUnique<base::Value>(in_value));
+}
+
+DictionaryValueUpdate* DictionaryValueUpdate::SetDictionaryWithoutPathExpansion(
+    base::StringPiece path,
+    std::unique_ptr<base::DictionaryValue> in_value) {
+  RecordKey(path);
+  base::DictionaryValue* dictionary_value = in_value.get();
+  value_->SetWithoutPathExpansion(path, std::move(in_value));
+
+  std::vector<std::string> full_path = path_;
+  full_path.push_back(path.as_string());
+  return update_->Insert(base::WrapUnique(new DictionaryValueUpdate(
+      update_, dictionary_value, std::move(full_path))));
+}
+
+bool DictionaryValueUpdate::GetBoolean(base::StringPiece path,
+                                       bool* out_value) const {
+  return value_->GetBoolean(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetInteger(base::StringPiece path,
+                                       int* out_value) const {
+  return value_->GetInteger(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetDouble(base::StringPiece path,
+                                      double* out_value) const {
+  return value_->GetDouble(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetString(base::StringPiece path,
+                                      std::string* out_value) const {
+  return value_->GetString(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetString(base::StringPiece path,
+                                      base::string16* out_value) const {
+  return value_->GetString(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetBinary(base::StringPiece path,
+                                      const base::Value** out_value) const {
+  return AsConstDictionary()->GetBinary(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetDictionary(
+    base::StringPiece path,
+    const base::DictionaryValue** out_value) const {
+  return AsConstDictionary()->GetDictionary(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetDictionary(base::StringPiece path,
+                                          DictionaryValueUpdate** out_value) {
+  base::DictionaryValue* dictionary_value = nullptr;
+  if (!value_->GetDictionary(path, &dictionary_value))
+    return false;
+
+  *out_value = update_->Insert(base::WrapUnique(new DictionaryValueUpdate(
+      update_, dictionary_value, ConcatPath(path_, path))));
+  return true;
+}
+
+bool DictionaryValueUpdate::GetList(base::StringPiece path,
+                                    const base::ListValue** out_value) const {
+  return AsConstDictionary()->GetList(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetList(base::StringPiece path,
+                                    base::ListValue** out_value) {
+  RecordPath(path);
+  return value_->GetList(path, out_value);
+}
+
+bool DictionaryValueUpdate::GetBooleanWithoutPathExpansion(
+    base::StringPiece key,
+    bool* out_value) const {
+  return value_->GetBooleanWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::GetIntegerWithoutPathExpansion(
+    base::StringPiece key,
+    int* out_value) const {
+  return value_->GetIntegerWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::GetDoubleWithoutPathExpansion(
+    base::StringPiece key,
+    double* out_value) const {
+  return value_->GetDoubleWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::GetStringWithoutPathExpansion(
+    base::StringPiece key,
+    std::string* out_value) const {
+  return value_->GetStringWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::GetStringWithoutPathExpansion(
+    base::StringPiece key,
+    base::string16* out_value) const {
+  return value_->GetStringWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::GetDictionaryWithoutPathExpansion(
+    base::StringPiece key,
+    const base::DictionaryValue** out_value) const {
+  return value_->GetDictionaryWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::GetDictionaryWithoutPathExpansion(
+    base::StringPiece key,
+    DictionaryValueUpdate** out_value) {
+  base::DictionaryValue* dictionary_value = nullptr;
+  if (!value_->GetDictionary(key, &dictionary_value))
+    return false;
+
+  std::vector<std::string> full_path = path_;
+  full_path.push_back(key.as_string());
+  *out_value = update_->Insert(base::WrapUnique(new DictionaryValueUpdate(
+      update_, dictionary_value, std::move(full_path))));
+  return true;
+}
+
+bool DictionaryValueUpdate::GetListWithoutPathExpansion(
+    base::StringPiece key,
+    const base::ListValue** out_value) const {
+  return value_->GetListWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::GetListWithoutPathExpansion(
+    base::StringPiece key,
+    base::ListValue** out_value) {
+  RecordKey(key);
+  return value_->GetListWithoutPathExpansion(key, out_value);
+}
+
+bool DictionaryValueUpdate::Remove(base::StringPiece path,
+                                   std::unique_ptr<base::Value>* out_value) {
+  if (!value_->Remove(path, out_value))
+    return false;
+
+  RecordPath(path);
+  return true;
+}
+
+bool DictionaryValueUpdate::RemoveWithoutPathExpansion(
+    base::StringPiece key,
+    std::unique_ptr<base::Value>* out_value) {
+  if (!value_->RemoveWithoutPathExpansion(key, out_value))
+    return false;
+
+  RecordKey(key);
+  return true;
+}
+
+bool DictionaryValueUpdate::RemovePath(
+    base::StringPiece path,
+    std::unique_ptr<base::Value>* out_value) {
+  if (!value_->RemovePath(path, out_value))
+    return false;
+
+  std::vector<base::StringPiece> split_path = SplitPath(path);
+  base::DictionaryValue* dict = value_;
+  for (size_t i = 0; i < split_path.size() - 1; ++i) {
+    if (!dict->GetDictionary(split_path[i], &dict)) {
+      split_path.resize(i + 1);
+      RecordSplitPath(split_path);
+      return true;
+    }
+  }
+  RecordPath(path);
+  return true;
+}
+
+base::DictionaryValue* DictionaryValueUpdate::AsDictionary() {
+  RecordSplitPath(std::vector<base::StringPiece>());
+  return value_;
+}
+
+const base::DictionaryValue* DictionaryValueUpdate::AsConstDictionary() const {
+  return value_;
+}
+
+void DictionaryValueUpdate::RecordKey(base::StringPiece key) {
+  RecordSplitPath({key});
+}
+
+void DictionaryValueUpdate::RecordPath(base::StringPiece path) {
+  RecordSplitPath(SplitPath(path));
+}
+
+void DictionaryValueUpdate::RecordSplitPath(
+    const std::vector<base::StringPiece>& path) {
+  update_->RecordPath(ConcatPath(path_, path));
+}
+
+std::vector<base::StringPiece> DictionaryValueUpdate::SplitPath(
+    base::StringPiece path) {
+  return base::SplitStringPiece(path, ".", base::TRIM_WHITESPACE,
+                                base::SPLIT_WANT_NONEMPTY);
+}
+
+std::vector<std::string> DictionaryValueUpdate::ConcatPath(
+    const std::vector<std::string>& base_path,
+    base::StringPiece path) {
+  return ConcatPath(base_path, SplitPath(path));
+}
+
+std::vector<std::string> DictionaryValueUpdate::ConcatPath(
+    const std::vector<std::string>& base_path,
+    const std::vector<base::StringPiece>& path) {
+  std::vector<std::string> full_path = base_path;
+  full_path.reserve(full_path.size() + path.size());
+  std::transform(path.begin(), path.end(), std::back_inserter(full_path),
+                 [](base::StringPiece s) { return s.as_string(); });
+  return full_path;
+}
+
+}  // namespace prefs