Pref service: support for incognito prefs

services/preferences/persistent_pref_store_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/persistent_pref_store_impl.h"
 
 #include <utility>
 
 #include "base/auto_reset.h"
 #include "base/memory/ptr_util.h"
 #include "base/stl_util.h"
 #include "base/values.h"
 #include "components/prefs/persistent_pref_store.h"
 #include "mojo/common/values_struct_traits.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "services/preferences/public/cpp/lib/util.h"
 
 namespace prefs {
 
-class PersistentPrefStoreImpl::Connection : public mojom::PersistentPrefStore {
+class PersistentPrefStoreImpl::Connection {
  public:
   Connection(PersistentPrefStoreImpl* pref_store,
-             mojom::PersistentPrefStoreRequest request,
              mojom::PrefStoreObserverPtr observer,
              ObservedPrefs observed_keys)
       : pref_store_(pref_store),
-        binding_(this, std::move(request)),
         observer_(std::move(observer)),
         observed_keys_(std::move(observed_keys)) {
-    auto error_callback =
+    observer_.set_connection_error_handler(
         base::Bind(&PersistentPrefStoreImpl::Connection::OnConnectionError,
-                   base::Unretained(this));
-    binding_.set_connection_error_handler(error_callback);
-    observer_.set_connection_error_handler(error_callback);
+                   base::Unretained(this)));
   }
 
-  ~Connection() override = default;
+  virtual ~Connection() = default;
 
-  void OnPrefValuesChanged(const std::vector<mojom::PrefUpdatePtr>& updates) {
-    if (write_in_progress_)
-      return;
-
+  virtual void OnPrefsChanged(
+      const std::vector<mojom::PrefUpdatePtr>& updates) {
     std::vector<mojom::PrefUpdatePtr> filtered_updates;
     for (const auto& update : updates) {
       if (base::ContainsKey(observed_keys_, update->key)) {
         filtered_updates.push_back(update->Clone());
       }
     }
     if (!filtered_updates.empty())
       observer_->OnPrefsChanged(std::move(filtered_updates));
   }
 
+ protected:
+  // Owns |this|.
+  PersistentPrefStoreImpl* const pref_store_;
+
+  void OnConnectionError() { pref_store_->OnConnectionError(this); }
+
+ private:
+  mojom::PrefStoreObserverPtr observer_;
+  const ObservedPrefs observed_keys_;
+
+  DISALLOW_COPY_AND_ASSIGN(Connection);
+};
+
+class PersistentPrefStoreImpl::WritableConnection
+    : public PersistentPrefStoreImpl::Connection,
+      public mojom::PersistentPrefStore {
+ public:
+  WritableConnection(PersistentPrefStoreImpl* pref_store,
+                     mojom::PersistentPrefStoreRequest request,
+                     mojom::PrefStoreObserverPtr observer,
+                     ObservedPrefs observed_keys)
+      : Connection(pref_store, std::move(observer), std::move(observed_keys)),
+        binding_(this, std::move(request)) {
+    binding_.set_connection_error_handler(base::Bind(
+        &PersistentPrefStoreImpl::WritableConnection::OnConnectionError,
+        base::Unretained(this)));
+  }
+
+  ~WritableConnection() override = default;
+
+  void OnPrefsChanged(
+      const std::vector<mojom::PrefUpdatePtr>& updates) override {
+    if (write_in_progress_)
+      return;
+    Connection::OnPrefsChanged(updates);
+  }
+
  private:
   // mojom::PersistentPrefStore:
   void SetValues(std::vector<mojom::PrefUpdatePtr> updates) override {
     base::AutoReset<bool> scoped_call_in_progress(&write_in_progress_, true);
     pref_store_->SetValues(std::move(updates));
   }
 
   void CommitPendingWrite() override { pref_store_->CommitPendingWrite(); }
   void SchedulePendingLossyWrites() override {
     pref_store_->SchedulePendingLossyWrites();
   }
   void ClearMutableValues() override { pref_store_->ClearMutableValues(); }
 
-  void OnConnectionError() { pref_store_->OnConnectionError(this); }
-
-  // Owns |this|.
-  PersistentPrefStoreImpl* const pref_store_;
+  // MSVC requires this as using a reference to the protected version in the
+  // super class in base::Bind doesn't work.
+  void OnConnectionError() { Connection::OnConnectionError(); }
 
   mojo::Binding<mojom::PersistentPrefStore> binding_;
-  mojom::PrefStoreObserverPtr observer_;
-  const ObservedPrefs observed_keys_;
 
   // If true then a write is in progress and any update notifications should be
   // ignored, as those updates would originate from ourselves.
   bool write_in_progress_ = false;
 
-  DISALLOW_COPY_AND_ASSIGN(Connection);
+  DISALLOW_COPY_AND_ASSIGN(WritableConnection);
 };
 
 PersistentPrefStoreImpl::PersistentPrefStoreImpl(
     scoped_refptr<PersistentPrefStore> backing_pref_store,
     base::OnceClosure on_initialized)
     : backing_pref_store_(backing_pref_store) {
   if (!backing_pref_store_->IsInitializationComplete()) {
     backing_pref_store_->AddObserver(this);
     on_initialized_ = std::move(on_initialized);
     initializing_ = true;
     backing_pref_store_->ReadPrefsAsync(nullptr);
   }
 }
 
 PersistentPrefStoreImpl::~PersistentPrefStoreImpl() = default;
 
 mojom::PersistentPrefStoreConnectionPtr
 PersistentPrefStoreImpl::CreateConnection(ObservedPrefs observed_prefs) {
   DCHECK(!initializing_);
   if (!backing_pref_store_->IsInitializationComplete()) {
     // |backing_pref_store_| initialization failed.
     return mojom::PersistentPrefStoreConnection::New(
         nullptr, nullptr, backing_pref_store_->GetReadError(),
         backing_pref_store_->ReadOnly());
   }
   mojom::PersistentPrefStorePtr pref_store_ptr;
   mojom::PrefStoreObserverPtr observer;
   mojom::PrefStoreObserverRequest observer_request =
       mojo::MakeRequest(&observer);
-  auto connection = base::MakeUnique<Connection>(
+  auto connection = base::MakeUnique<WritableConnection>(
       this, mojo::MakeRequest(&pref_store_ptr), std::move(observer),
       std::move(observed_prefs));
   auto* connection_ptr = connection.get();
   connections_.insert(std::make_pair(connection_ptr, std::move(connection)));
   return mojom::PersistentPrefStoreConnection::New(
       mojom::PrefStoreConnection::New(std::move(observer_request),
                                       backing_pref_store_->GetValues(), true),
       std::move(pref_store_ptr), backing_pref_store_->GetReadError(),
       backing_pref_store_->ReadOnly());
 }
 
 void PersistentPrefStoreImpl::OnPrefValueChanged(const std::string& key) {}
 
 void PersistentPrefStoreImpl::OnInitializationCompleted(bool succeeded) {
   DCHECK(initializing_);
   backing_pref_store_->RemoveObserver(this);
   initializing_ = false;
   std::move(on_initialized_).Run();
 }
 
+void PersistentPrefStoreImpl::AddObserver(
+    const std::vector<std::string>& prefs_to_observe,
+    const AddObserverCallback& callback) {
+  mojom::PrefStoreObserverPtr observer;
+  auto observer_request = mojo::MakeRequest(&observer);
+  auto connection = base::MakeUnique<Connection>(
+      this, std::move(observer),
+      ObservedPrefs(prefs_to_observe.begin(), prefs_to_observe.end()));
+  auto* connection_ptr = connection.get();
+  connections_.insert(std::make_pair(connection_ptr, std::move(connection)));
+  callback.Run(mojom::PrefStoreConnection::New(
+      std::move(observer_request), backing_pref_store_->GetValues(),
+      backing_pref_store_->IsInitializationComplete()));
+}
+
 void PersistentPrefStoreImpl::SetValues(
     std::vector<mojom::PrefUpdatePtr> updates) {
   for (auto& entry : connections_)
-    entry.first->OnPrefValuesChanged(updates);
+    entry.first->OnPrefsChanged(updates);
 
   for (auto& update : updates) {
     if (update->value->is_atomic_update()) {
       auto& value = update->value->get_atomic_update();
       if (value) {
         backing_pref_store_->SetValue(update->key, std::move(value),
                                       update->flags);
       } else {
         backing_pref_store_->RemoveValue(update->key, update->flags);
       }
@@ skipping 37 matching lines @@
 
 void PersistentPrefStoreImpl::ClearMutableValues() {
   backing_pref_store_->ClearMutableValues();
 }
 
 void PersistentPrefStoreImpl::OnConnectionError(Connection* connection) {
   connections_.erase(connection);
 }
 
 }  // namespace prefs