text: // Copyright 2014 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 "chromeos/dbus/bluetooth_gatt_descriptor_service_provider.h"
  
  #include "base/bind.h"
  #include "base/logging.h"
  #include "base/memory/weak_ptr.h"
  #include "base/strings/string_util.h"
  #include "base/sys_info.h"
  #include "base/threading/platform_thread.h"
  #include "chromeos/dbus/fake_bluetooth_gatt_descriptor_service_provider.h"
  #include "dbus/exported_object.h"
  #include "dbus/message.h"
  #include "third_party/cros_system_api/dbus/service_constants.h"
  
  namespace chromeos {
  namespace {
  const char kErrorInvalidArgs[] =
      "org.freedesktop.DBus.Error.InvalidArgs";
  const char kErrorPropertyReadOnly[] =
      "org.freedesktop.DBus.Error.PropertyReadOnly";
  const char kErrorFailed[] =
      "org.freedesktop.DBus.Error.Failed";
  }  // namespace
  
  // The BluetoothGattDescriptorServiceProvider implementation used in production.
  class BluetoothGattDescriptorServiceProviderImpl
      : public BluetoothGattDescriptorServiceProvider {
   public:
    BluetoothGattDescriptorServiceProviderImpl(
        dbus::Bus* bus,
        const dbus::ObjectPath& object_path,
        Delegate* delegate,
        const std::string& uuid,
        const std::vector<std::string>& permissions,
        const dbus::ObjectPath& characteristic_path)
        : origin_thread_id_(base::PlatformThread::CurrentId()),
          uuid_(uuid),
          bus_(bus),
          delegate_(delegate),
          object_path_(object_path),
          characteristic_path_(characteristic_path),
          weak_ptr_factory_(this) {
      VLOG(1) << "Created Bluetooth GATT characteristic descriptor: "
              << object_path.value() << " UUID: " << uuid;
      DCHECK(bus_);
      DCHECK(delegate_);
      DCHECK(!uuid_.empty());
      DCHECK(object_path_.IsValid());
      DCHECK(characteristic_path_.IsValid());
      DCHECK(StartsWithASCII(
          object_path_.value(), characteristic_path_.value() + "/", true));
  
      exported_object_ = bus_->GetExportedObject(object_path_);
  
      exported_object_->ExportMethod(
          dbus::kDBusPropertiesInterface,
          dbus::kDBusPropertiesGet,
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::Get,
                     weak_ptr_factory_.GetWeakPtr()),
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnExported,
                     weak_ptr_factory_.GetWeakPtr()));
  
      exported_object_->ExportMethod(
          dbus::kDBusPropertiesInterface,
          dbus::kDBusPropertiesSet,
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::Set,
                     weak_ptr_factory_.GetWeakPtr()),
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnExported,
                     weak_ptr_factory_.GetWeakPtr()));
  
      exported_object_->ExportMethod(
          dbus::kDBusPropertiesInterface,
          dbus::kDBusPropertiesGetAll,
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::GetAll,
                     weak_ptr_factory_.GetWeakPtr()),
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnExported,
                     weak_ptr_factory_.GetWeakPtr()));
    }
  
    virtual ~BluetoothGattDescriptorServiceProviderImpl() {
      VLOG(1) << "Cleaning up Bluetooth GATT characteristic descriptor: "
              << object_path_.value();
      bus_->UnregisterExportedObject(object_path_);
    }
  
    // BluetoothGattDescriptorServiceProvider override.
    virtual void SendValueChanged(const std::vector<uint8>& value) OVERRIDE {
      VLOG(2) << "Emitting a PropertiesChanged signal for descriptor value.";
      dbus::Signal signal(
          dbus::kDBusPropertiesInterface,
          dbus::kDBusPropertiesChangedSignal);
      dbus::MessageWriter writer(&signal);
      dbus::MessageWriter array_writer(NULL);
      dbus::MessageWriter dict_entry_writer(NULL);
      dbus::MessageWriter variant_writer(NULL);
  
      // interface_name
      writer.AppendString(
          bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface);
  
      // changed_properties
      writer.OpenArray("{sv}", &array_writer);
      array_writer.OpenDictEntry(&dict_entry_writer);
      dict_entry_writer.AppendString(bluetooth_gatt_descriptor::kValueProperty);
      dict_entry_writer.OpenVariant("ay", &variant_writer);
      variant_writer.AppendArrayOfBytes(value.data(), value.size());
      dict_entry_writer.CloseContainer(&variant_writer);
      array_writer.CloseContainer(&dict_entry_writer);
      writer.CloseContainer(&array_writer);
  
      // invalidated_properties.
      writer.OpenArray("s", &array_writer);
      writer.CloseContainer(&array_writer);
  
      exported_object_->SendSignal(&signal);
    }
  
   private:
    // Returns true if the current thread is on the origin thread.
    bool OnOriginThread() {
      return base::PlatformThread::CurrentId() == origin_thread_id_;
    }
  
    // Called by dbus:: when the Bluetooth daemon fetches a single property of
    // the descriptor.
    void Get(dbus::MethodCall* method_call,
             dbus::ExportedObject::ResponseSender response_sender) {
      VLOG(2) << "BluetoothGattDescriptorServiceProvider::Get: "
              << object_path_.value();
      DCHECK(OnOriginThread());
  
      dbus::MessageReader reader(method_call);
  
      std::string interface_name;
      std::string property_name;
      if (!reader.PopString(&interface_name) ||
          !reader.PopString(&property_name) ||
          reader.HasMoreData()) {
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, kErrorInvalidArgs, "Expected 'ss'.");
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // Only the GATT descriptor interface is supported.
      if (interface_name !=
          bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface) {
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, kErrorInvalidArgs,
                "No such interface: '" + interface_name + "'.");
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // If getting the "Value" property, obtain the value from the delegate.
      if (property_name == bluetooth_gatt_descriptor::kValueProperty) {
        DCHECK(delegate_);
        delegate_->GetDescriptorValue(
            base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnGet,
                       weak_ptr_factory_.GetWeakPtr(),
                       method_call, response_sender),
            base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnFailure,
                       weak_ptr_factory_.GetWeakPtr(),
                       method_call, response_sender));
        return;
      }
  
      scoped_ptr<dbus::Response> response =
          dbus::Response::FromMethodCall(method_call);
      dbus::MessageWriter writer(response.get());
      dbus::MessageWriter variant_writer(NULL);
  
      // TODO(armansito): Process the "Permissions" property below.
      if (property_name == bluetooth_gatt_descriptor::kUUIDProperty) {
        writer.OpenVariant("s", &variant_writer);
        variant_writer.AppendString(uuid_);
        writer.CloseContainer(&variant_writer);
      } else if (property_name ==
                 bluetooth_gatt_descriptor::kCharacteristicProperty) {
        writer.OpenVariant("o", &variant_writer);
        variant_writer.AppendObjectPath(characteristic_path_);
        writer.CloseContainer(&variant_writer);
      } else {
        response = dbus::ErrorResponse::FromMethodCall(
            method_call, kErrorInvalidArgs,
            "No such property: '" + property_name + "'.")
            .PassAs<dbus::Response>();
      }
  
      response_sender.Run(response.Pass());
    }
  
    // Called by dbus:: when the Bluetooth daemon sets a single property of the
    // descriptor.
    void Set(dbus::MethodCall* method_call,
             dbus::ExportedObject::ResponseSender response_sender) {
      VLOG(2) << "BluetoothGattDescriptorServiceProvider::Set: "
              << object_path_.value();
      DCHECK(OnOriginThread());
  
      dbus::MessageReader reader(method_call);
  
      std::string interface_name;
      std::string property_name;
      dbus::MessageReader variant_reader(NULL);
      if (!reader.PopString(&interface_name) ||
          !reader.PopString(&property_name) ||
          !reader.PopVariant(&variant_reader) ||
          reader.HasMoreData()) {
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, kErrorInvalidArgs, "Expected 'ssv'.");
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // Only the GATT descriptor interface is allowed.
      if (interface_name !=
          bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface) {
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, kErrorInvalidArgs,
                "No such interface: '" + interface_name + "'.");
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // Only the "Value" property is writeable.
      if (property_name != bluetooth_gatt_descriptor::kValueProperty) {
        std::string error_name;
        std::string error_message;
        if (property_name == bluetooth_gatt_descriptor::kUUIDProperty ||
            property_name == bluetooth_gatt_descriptor::kCharacteristicProperty) {
          error_name = kErrorPropertyReadOnly;
          error_message = "Read-only property: '" + property_name + "'.";
        } else {
          error_name = kErrorInvalidArgs;
          error_message = "No such property: '" + property_name + "'.";
        }
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, error_name, error_message);
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // Obtain the value.
      const uint8* bytes = NULL;
      size_t length = 0;
      if (!variant_reader.PopArrayOfBytes(&bytes, &length)) {
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, kErrorInvalidArgs,
                "Property '" + property_name + "' has type 'ay'.");
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // Pass the set request onto the delegate.
      std::vector<uint8> value(bytes, bytes + length);
      DCHECK(delegate_);
      delegate_->SetDescriptorValue(
          value,
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnSet,
                     weak_ptr_factory_.GetWeakPtr(),
                     method_call, response_sender),
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnFailure,
                     weak_ptr_factory_.GetWeakPtr(),
                     method_call, response_sender));
    }
  
    // Called by dbus:: when the Bluetooth daemon fetches all properties of the
    // descriptor.
    void GetAll(dbus::MethodCall* method_call,
                dbus::ExportedObject::ResponseSender response_sender) {
      VLOG(2) << "BluetoothGattDescriptorServiceProvider::GetAll: "
              << object_path_.value();
      DCHECK(OnOriginThread());
  
      dbus::MessageReader reader(method_call);
  
      std::string interface_name;
      if (!reader.PopString(&interface_name) || reader.HasMoreData()) {
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, kErrorInvalidArgs, "Expected 's'.");
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // Only the GATT descriptor interface is supported.
      if (interface_name !=
          bluetooth_gatt_descriptor::kBluetoothGattDescriptorInterface) {
        scoped_ptr<dbus::ErrorResponse> error_response =
            dbus::ErrorResponse::FromMethodCall(
                method_call, kErrorInvalidArgs,
                "No such interface: '" + interface_name + "'.");
        response_sender.Run(error_response.PassAs<dbus::Response>());
        return;
      }
  
      // Try to obtain the value from the delegate. We will construct the
      // response in the success callback.
      DCHECK(delegate_);
      delegate_->GetDescriptorValue(
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnGetAll,
                     weak_ptr_factory_.GetWeakPtr(),
                     method_call, response_sender),
          base::Bind(&BluetoothGattDescriptorServiceProviderImpl::OnFailure,
                     weak_ptr_factory_.GetWeakPtr(),
                     method_call, response_sender));
    }
  
    // Called by dbus:: when a method is exported.
    void OnExported(const std::string& interface_name,
                    const std::string& method_name,
                    bool success) {
      LOG_IF(WARNING, !success) << "Failed to export "
                                << interface_name << "." << method_name;
    }
  
    // Called by the Delegate in response to a method to call to get all
    // properties, in which the delegate has successfully returned the
    // descriptor value.
    void OnGetAll(dbus::MethodCall* method_call,
                  dbus::ExportedObject::ResponseSender response_sender,
                  const std::vector<uint8>& value) {
      VLOG(2) << "Descriptor value obtained from delegate. Responding to "
              << "GetAll.";
  
      scoped_ptr<dbus::Response> response =
          dbus::Response::FromMethodCall(method_call);
      dbus::MessageWriter writer(response.get());
      dbus::MessageWriter array_writer(NULL);
      dbus::MessageWriter dict_entry_writer(NULL);
      dbus::MessageWriter variant_writer(NULL);
  
      writer.OpenArray("{sv}", &array_writer);
  
      array_writer.OpenDictEntry(&dict_entry_writer);
      dict_entry_writer.AppendString(
          bluetooth_gatt_descriptor::kUUIDProperty);
      dict_entry_writer.AppendVariantOfString(uuid_);
      array_writer.CloseContainer(&dict_entry_writer);
  
      array_writer.OpenDictEntry(&dict_entry_writer);
      dict_entry_writer.AppendString(
          bluetooth_gatt_descriptor::kCharacteristicProperty);
      dict_entry_writer.AppendVariantOfObjectPath(characteristic_path_);
      array_writer.CloseContainer(&dict_entry_writer);
  
      array_writer.OpenDictEntry(&dict_entry_writer);
      dict_entry_writer.AppendString(
          bluetooth_gatt_descriptor::kValueProperty);
      dict_entry_writer.OpenVariant("ay", &variant_writer);
      variant_writer.AppendArrayOfBytes(value.data(), value.size());
      dict_entry_writer.CloseContainer(&variant_writer);
      array_writer.CloseContainer(&dict_entry_writer);
  
      // TODO(armansito): Process "Permissions" property.
  
      writer.CloseContainer(&array_writer);
  
      response_sender.Run(response.Pass());
    }
  
    // Called by the Delegate in response to a successful method call to get the
    // descriptor value.
    void OnGet(dbus::MethodCall* method_call,
               dbus::ExportedObject::ResponseSender response_sender,
               const std::vector<uint8>& value) {
      VLOG(2) << "Returning descriptor value obtained from delegate.";
      scoped_ptr<dbus::Response> response =
          dbus::Response::FromMethodCall(method_call);
      dbus::MessageWriter writer(response.get());
      dbus::MessageWriter variant_writer(NULL);
  
      writer.OpenVariant("ay", &variant_writer);
      variant_writer.AppendArrayOfBytes(value.data(), value.size());
      writer.CloseContainer(&variant_writer);
  
      response_sender.Run(response.Pass());
    }
  
    // Called by the Delegate in response to a successful method call to set the
    // descriptor value.
    void OnSet(dbus::MethodCall* method_call,
               dbus::ExportedObject::ResponseSender response_sender) {
      VLOG(2) << "Successfully set descriptor value. Return success.";
      response_sender.Run(dbus::Response::FromMethodCall(method_call));
    }
  
    // Called by the Delegate in response to a failed method call to get or set
    // the descriptor value.
    void OnFailure(dbus::MethodCall* method_call,
                   dbus::ExportedObject::ResponseSender response_sender) {
      VLOG(2) << "Failed to get/set descriptor value. Report error.";
      scoped_ptr<dbus::ErrorResponse> error_response =
          dbus::ErrorResponse::FromMethodCall(
              method_call, kErrorFailed,
              "Failed to get/set descriptor value.");
      response_sender.Run(error_response.PassAs<dbus::Response>());
    }
  
    // Origin thread (i.e. the UI thread in production).
    base::PlatformThreadId origin_thread_id_;
  
    // 128-bit descriptor UUID of this object.
    std::string uuid_;
  
    // D-Bus bus object is exported on, not owned by this object and must
    // outlive it.
    dbus::Bus* bus_;
  
    // Incoming methods to get and set the "Value" property are passed on to the
    // delegate and callbacks passed to generate a reply. |delegate_| is generally
    // the object that owns this one and must outlive it.
    Delegate* delegate_;
  
    // D-Bus object path of object we are exporting, kept so we can unregister
    // again in our destructor.
    dbus::ObjectPath object_path_;
  
    // Object path of the GATT characteristic that the exported descriptor belongs
    // to.
    dbus::ObjectPath characteristic_path_;
  
    // D-Bus object we are exporting, owned by this object.
    scoped_refptr<dbus::ExportedObject> exported_object_;
  
    // Weak pointer factory for generating 'this' pointers that might live longer
    // than we do.
    // Note: This should remain the last member so it'll be destroyed and
    // invalidate its weak pointers before any other members are destroyed.
    base::WeakPtrFactory<BluetoothGattDescriptorServiceProviderImpl>
        weak_ptr_factory_;
  
    DISALLOW_COPY_AND_ASSIGN(BluetoothGattDescriptorServiceProviderImpl);
  };
  
  BluetoothGattDescriptorServiceProvider::
      BluetoothGattDescriptorServiceProvider() {
  }
  
  BluetoothGattDescriptorServiceProvider::
      ~BluetoothGattDescriptorServiceProvider() {
  }
  
  // static
  BluetoothGattDescriptorServiceProvider*
  BluetoothGattDescriptorServiceProvider::Create(
      dbus::Bus* bus,
      const dbus::ObjectPath& object_path,
      Delegate* delegate,
      const std::string& uuid,
      const std::vector<std::string>& permissions,
      const dbus::ObjectPath& characteristic_path) {
    if (base::SysInfo::IsRunningOnChromeOS()) {
      return new BluetoothGattDescriptorServiceProviderImpl(
          bus, object_path, delegate, uuid, permissions, characteristic_path);
    }
    return new FakeBluetoothGattDescriptorServiceProvider(
        object_path, delegate, uuid, permissions, characteristic_path);
  }
  
  }  // namespace chromeos
  