Add a mojo bridge for PersistentPrefStore.

services/preferences/public/cpp/user_prefs_impl.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/user_prefs_impl.h"
+
+#include <memory>
+#include <set>
+#include <utility>
+
+#include "base/macros.h"
+#include "base/values.h"
+#include "components/prefs/json_pref_store.h"
+#include "components/user_prefs/tracked/pref_hash_store_impl.h"
+#include "components/user_prefs/tracked/segregated_pref_store.h"
+#include "components/user_prefs/tracked/tracked_preferences_migration.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+#if defined(OS_WIN)
+#include "components/user_prefs/tracked/registry_hash_store_contents_win.h"
+#endif
+
+namespace prefs {
+namespace {
+
+class ValidationDelegatePtrHolder

[tibell, 2017/03/08 03:39:54]

Document what each class does. I'm guess this is:

// Allows a mojom::TrackedPreferenceValidationDelegatePtr to be refcounted.

+    : public base::RefCounted<ValidationDelegatePtrHolder> {
+ public:
+  ValidationDelegatePtrHolder(mojom::TrackedPreferenceValidationDelegatePtr ptr)
+      : ptr_(std::move(ptr)) {}
+
+  mojom::TrackedPreferenceValidationDelegate* get() { return ptr_.get(); }
+
+ private:
+  friend class base::RefCounted<ValidationDelegatePtrHolder>;
+  ~ValidationDelegatePtrHolder() = default;
+
+  mojom::TrackedPreferenceValidationDelegatePtr ptr_;
+};
+
+class PersistentPrefStoreImpl : public mojom::PersistentPrefStore {
+ public:
+  explicit PersistentPrefStoreImpl(
+      scoped_refptr<::PersistentPrefStore> pref_store);
+
+  ~PersistentPrefStoreImpl() override;
+
+  // mojom::PersistentPrefStore:
+  void SetValue(const std::string& key,
+                std::unique_ptr<base::Value> value,
+                uint32_t flags) override;
+
+  void CommitPendingWrite() override;
+  void SchedulePendingLossyWrites() override;
+  void ClearMutableValues() override;
+
+ private:
+  scoped_refptr<ValidationDelegatePtrHolder> validation_delegate_ref_;
+  scoped_refptr<::PersistentPrefStore> backing_pref_store_;
+
+  DISALLOW_COPY_AND_ASSIGN(PersistentPrefStoreImpl);
+};
+
+PersistentPrefStoreImpl::PersistentPrefStoreImpl(
+    scoped_refptr<::PersistentPrefStore> pref_store)
+    : backing_pref_store_(std::move(pref_store)) {}
+
+PersistentPrefStoreImpl::~PersistentPrefStoreImpl() = default;
+
+// mojomJsonPrefStore:
+void PersistentPrefStoreImpl::SetValue(const std::string& key,
+                                       std::unique_ptr<base::Value> value,
+                                       uint32_t flags) {
+  if (value)
+    backing_pref_store_->SetValue(key, std::move(value), flags);
+  else
+    backing_pref_store_->RemoveValue(key, flags);
+}
+
+void PersistentPrefStoreImpl::CommitPendingWrite() {
+  backing_pref_store_->CommitPendingWrite();
+}
+
+void PersistentPrefStoreImpl::SchedulePendingLossyWrites() {
+  backing_pref_store_->SchedulePendingLossyWrites();
+}
+
+void PersistentPrefStoreImpl::ClearMutableValues() {
+  backing_pref_store_->ClearMutableValues();
+}
+
+void CallConnectCallback(
+    PersistentPrefStore* pref_store,

[tibell, 2017/03/08 03:39:54]

Should be a scoped_refptr I think.

+    const mojom::PersistentPrefStoreConnector::ConnectCallback& callback) {
+  mojom::PersistentPrefStorePtr pref_store_ptr;
+  mojo::MakeStrongBinding(
+      base::MakeUnique<PersistentPrefStoreImpl>(std::move(pref_store)),
+      mojo::MakeRequest(&pref_store_ptr));
+  callback.Run(pref_store->GetReadError(), pref_store->ReadOnly(),
+               pref_store->IsInitializationComplete() ? pref_store->GetValues()
+                                                      : nullptr,
+               std::move(pref_store_ptr));
+}
+
+void RemoveValueSilently(const base::WeakPtr<JsonPrefStore> pref_store,
+                         const std::string& key) {
+  if (pref_store) {
+    pref_store->RemoveValueSilently(
+        key, WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  }
+}
+
+std::unique_ptr<PrefHashStore> CreatePrefHashStore(
+    const std::string& seed,
+    const std::string& legacy_device_id,
+    bool use_super_mac) {
+  return std::unique_ptr<PrefHashStore>(

[tibell, 2017/03/08 03:39:54]

Would MakeUnique work since the function has a return type of the right pointer
type?

+      new PrefHashStoreImpl(seed, legacy_device_id, use_super_mac));
+}
+
+std::pair<std::unique_ptr<PrefHashStore>, std::unique_ptr<HashStoreContents>>
+GetExternalVerificationPrefHashStorePair(const std::string& seed,
+                                         const std::string& legacy_device_id,
+                                         const base::string16& registry_path,
+                                         const base::FilePath& prefs_path) {
+#if defined(OS_WIN)
+  return std::make_pair(
+      base::MakeUnique<PrefHashStoreImpl>(seed, legacy_device_id,
+                                          false /* use_super_mac */),
+      base::MakeUnique<RegistryHashStoreContentsWin>(
+          registry_path, prefs_path.DirName().BaseName().LossyDisplayName()));
+#else
+  return std::make_pair(nullptr, nullptr);
+#endif
+}
+
+class PersistentPrefStoreConnectorImpl
+    : public mojom::PersistentPrefStoreConnector,
+      public PrefStore::Observer {
+ public:
+  PersistentPrefStoreConnectorImpl(
+      scoped_refptr<PersistentPrefStore> backing_pref_store,
+      scoped_refptr<ValidationDelegatePtrHolder> validation_delegate)
+      : backing_pref_store_(backing_pref_store),
+        validation_delegate_holder_(std::move(validation_delegate)) {}
+
+  ~PersistentPrefStoreConnectorImpl() override = default;
+
+  // mojom::PersistentPrefStoreConnector override:
+  void Connect(const ConnectCallback& callback) override {
+    if (backing_pref_store_->IsInitializationComplete()) {
+      CallConnectCallback(backing_pref_store_.get(), callback);
+      return;
+    }
+    connect_callbacks_.push_back(callback);
+    if (loading_)
+      return;
+
+    backing_pref_store_->AddObserver(this);
+    loading_ = true;
+    backing_pref_store_->ReadPrefsAsync(nullptr);
+  }
+
+  static void CreateUserPrefs(
+      const base::FilePath& pref_filename,
+      const scoped_refptr<base::SequencedTaskRunner>& io_task_runner,
+      mojom::PersistentPrefStoreConnectorRequest request) {
+    mojo::MakeStrongBinding(
+        base::MakeUnique<PersistentPrefStoreConnectorImpl>(
+            new JsonPrefStore(pref_filename, io_task_runner, nullptr), nullptr),
+        std::move(request));
+  }
+
+  static void CreateSegregatedUserPrefs(
+      const base::FilePath& unprotected_pref_filename,
+      const base::FilePath& protected_pref_filename,
+      const std::vector<PrefHashFilter::TrackedPreferenceMetadata>&
+          tracking_configuration,
+      size_t reporting_ids_count,
+      const std::string& seed,
+      const std::string& legacy_device_id,
+      const base::string16& registry_path,
+      mojom::TrackedPreferenceValidationDelegatePtrInfo
+          validation_delegate_info,
+      const base::Closure& on_reset_on_load,
+      const scoped_refptr<base::SequencedTaskRunner>& io_task_runner,
+      mojom::PersistentPrefStoreConnectorRequest request) {
+    scoped_refptr<ValidationDelegatePtrHolder> validation_delegate_holder(

[tibell, 2017/03/08 03:39:54]

There's lots of setup going on here. Is this code copied from elsewhere?

+        new ValidationDelegatePtrHolder(
+            mojo::MakeProxy(std::move(validation_delegate_info))));
+    std::vector<PrefHashFilter::TrackedPreferenceMetadata>
+        unprotected_configuration;
+    std::vector<PrefHashFilter::TrackedPreferenceMetadata>
+        protected_configuration;
+    std::set<std::string> protected_pref_names;
+    std::set<std::string> unprotected_pref_names;
+    for (const auto& metadata : tracking_configuration) {
+      if (metadata.enforcement_level > PrefHashFilter::NO_ENFORCEMENT) {
+        protected_configuration.push_back(metadata);
+        protected_pref_names.insert(metadata.name);
+      } else {
+        unprotected_configuration.push_back(metadata);
+        unprotected_pref_names.insert(metadata.name);
+      }
+    }
+
+    std::unique_ptr<PrefHashFilter> unprotected_pref_hash_filter(
+        new PrefHashFilter(CreatePrefHashStore(seed, legacy_device_id, false),
+                           GetExternalVerificationPrefHashStorePair(
+                               seed, legacy_device_id, registry_path,
+                               unprotected_pref_filename),
+                           unprotected_configuration, base::Closure(),
+                           validation_delegate_holder->get(),
+                           reporting_ids_count, false));
+    std::unique_ptr<PrefHashFilter> protected_pref_hash_filter(
+        new PrefHashFilter(CreatePrefHashStore(seed, legacy_device_id, true),
+                           GetExternalVerificationPrefHashStorePair(
+                               seed, legacy_device_id, registry_path,
+                               unprotected_pref_filename),
+                           protected_configuration, on_reset_on_load,
+                           validation_delegate_holder->get(),
+                           reporting_ids_count, true));
+
+    PrefHashFilter* raw_unprotected_pref_hash_filter =
+        unprotected_pref_hash_filter.get();
+    PrefHashFilter* raw_protected_pref_hash_filter =
+        protected_pref_hash_filter.get();
+
+    scoped_refptr<JsonPrefStore> unprotected_pref_store(
+        new JsonPrefStore(unprotected_pref_filename, io_task_runner.get(),
+                          std::move(unprotected_pref_hash_filter)));
+    scoped_refptr<JsonPrefStore> protected_pref_store(
+        new JsonPrefStore(protected_pref_filename, io_task_runner.get(),
+                          std::move(protected_pref_hash_filter)));
+
+    SetupTrackedPreferencesMigration(
+        unprotected_pref_names, protected_pref_names,
+        base::Bind(&RemoveValueSilently, unprotected_pref_store->AsWeakPtr()),
+        base::Bind(&RemoveValueSilently, protected_pref_store->AsWeakPtr()),
+        base::Bind(&JsonPrefStore::RegisterOnNextSuccessfulWriteReply,
+                   unprotected_pref_store->AsWeakPtr()),
+        base::Bind(&JsonPrefStore::RegisterOnNextSuccessfulWriteReply,
+                   protected_pref_store->AsWeakPtr()),
+        CreatePrefHashStore(seed, legacy_device_id, false),
+        CreatePrefHashStore(seed, legacy_device_id, true),
+        raw_unprotected_pref_hash_filter, raw_protected_pref_hash_filter);
+
+    mojo::MakeStrongBinding(
+        base::MakeUnique<PersistentPrefStoreConnectorImpl>(
+            new SegregatedPrefStore(unprotected_pref_store,
+                                    protected_pref_store, protected_pref_names),
+            std::move(validation_delegate_holder)),
+        std::move(request));
+  }
+
+ private:
+  void OnPrefValueChanged(const std::string& key) override {}

[tibell, 2017/03/08 03:39:54]

Add a comment why it's OK to ignore this.

+
+  void OnInitializationCompleted(bool succeeded) override {
+    loading_ = false;
+    backing_pref_store_->RemoveObserver(this);
+    for (const auto& callback : connect_callbacks_) {
+      CallConnectCallback(backing_pref_store_.get(), callback);
+    }
+    connect_callbacks_.clear();
+  }
+
+  scoped_refptr<PersistentPrefStore> backing_pref_store_;
+  scoped_refptr<ValidationDelegatePtrHolder> validation_delegate_holder_;
+
+  bool loading_ = false;
+  std::vector<ConnectCallback> connect_callbacks_;
+
+  DISALLOW_COPY_AND_ASSIGN(PersistentPrefStoreConnectorImpl);
+};
+
+}  // namespace
+
+void CreateUserPrefs(
+    const base::FilePath& pref_filename,
+    const scoped_refptr<base::SingleThreadTaskRunner>& connection_task_runner,
+    const scoped_refptr<base::SequencedTaskRunner>& io_task_runner,
+    mojom::PersistentPrefStoreConnectorRequest request) {
+  connection_task_runner->PostTask(
+      FROM_HERE,
+      base::Bind(&PersistentPrefStoreConnectorImpl::CreateUserPrefs,
+                 pref_filename, io_task_runner, base::Passed(&request)));
+}
+
+void CreateSegregatedUserPrefs(
+    const base::FilePath& unprotected_pref_filename,
+    const base::FilePath& protected_pref_filename,
+    const std::vector<PrefHashFilter::TrackedPreferenceMetadata>&
+        tracking_configuration,
+    size_t reporting_ids_count,
+    const std::string& seed,
+    const std::string& legacy_device_id,
+    const base::string16& registry_path,
+    mojom::TrackedPreferenceValidationDelegatePtr validation_delegate,
+    const base::Closure& on_reset_on_load,
+    const scoped_refptr<base::SingleThreadTaskRunner>& connection_task_runner,
+    const scoped_refptr<base::SequencedTaskRunner>& io_task_runner,
+    mojom::PersistentPrefStoreConnectorRequest request) {
+  connection_task_runner->PostTask(
+      FROM_HERE,
+      base::Bind(&PersistentPrefStoreConnectorImpl::CreateSegregatedUserPrefs,
+                 unprotected_pref_filename, protected_pref_filename,
+                 tracking_configuration, reporting_ids_count, seed,
+                 legacy_device_id, registry_path,
+                 base::Passed(validation_delegate.PassInterface()),
+                 on_reset_on_load, io_task_runner, base::Passed(&request)));
+}
+
+}  // namespace prefs