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// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/dbus/xdg/request.h"
#include <memory>
#include <utility>
#include "base/functional/bind.h"
#include "base/logging.h"
#include "base/nix/xdg_util.h"
#include "base/unguessable_token.h"
#include "components/dbus/properties/types.h"
#include "dbus/bus.h"
#include "dbus/message.h"
#include "dbus/object_path.h"
#include "dbus/object_proxy.h"
namespace dbus_xdg {
namespace {
constexpr char kPortalServiceName[] = "org.freedesktop.portal.Desktop";
constexpr char kRequestInterface[] = "org.freedesktop.portal.Request";
constexpr char kSignalResponse[] = "Response";
// These constants are defined in
// https://flatpak.github.io/xdg-desktop-portal/docs/doc-org.freedesktop.portal.Request.html#org-freedesktop-portal-request-response
enum class ResponseCode : uint32_t {
kSuccess = 0,
kUserCancelled = 1,
kOther = 2,
};
} // namespace
Request::Request(scoped_refptr<dbus::Bus> bus,
dbus::ObjectProxy* object_proxy,
const std::string& interface_name,
const std::string& method_name,
const DbusType& arguments,
DbusDictionary&& options,
ResponseCallback callback,
const std::string& test_portal_service_name)
: bus_(bus),
callback_(std::move(callback)),
portal_service_name_(test_portal_service_name.empty()
? kPortalServiceName
: test_portal_service_name) {
CHECK(bus_);
CHECK(callback_);
auto handle_token = base::UnguessableToken::Create().ToString();
request_object_path_ =
dbus::ObjectPath(base::nix::XdgDesktopPortalRequestPath(
bus->GetConnectionName(), handle_token));
auto* request_proxy =
bus->GetObjectProxy(portal_service_name_, request_object_path_);
// Connect to the "Response" signal before making the method call to avoid a
// race condition.
request_proxy->ConnectToSignal(
kRequestInterface, kSignalResponse,
base::BindRepeating(&Request::OnResponseSignal,
weak_ptr_factory_.GetWeakPtr()),
base::BindOnce(&Request::OnSignalConnected,
weak_ptr_factory_.GetWeakPtr()));
dbus::MethodCall method_call(interface_name, method_name);
dbus::MessageWriter writer(&method_call);
arguments.Write(&writer);
options.PutAs("handle_token", DbusString(handle_token));
options.Write(&writer);
object_proxy->CallMethodWithErrorResponse(
&method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
base::BindOnce(&Request::OnMethodResponse,
weak_ptr_factory_.GetWeakPtr()));
}
Request::~Request() {
if (!bus_) {
return;
}
auto* request_proxy =
bus_->GetObjectProxy(portal_service_name_, request_object_path_);
dbus::MethodCall method_call(kRequestInterface, "Close");
request_proxy->CallMethod(
&method_call, dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
base::BindOnce(
[](scoped_refptr<dbus::Bus> bus, dbus::ObjectPath request_object_path,
std::string portal_service_name, dbus::Response*) {
bus->RemoveObjectProxy(portal_service_name, request_object_path,
base::DoNothing());
},
std::move(bus_), std::move(request_object_path_),
std::move(portal_service_name_)));
}
void Request::OnMethodResponse(dbus::Response* response,
dbus::ErrorResponse* error_response) {
if (!response) {
VLOG(1) << "Method call failed.";
Finish(base::unexpected(ResponseError::kMethodCallFailed));
return;
}
// Requests always have a single object path in their response.
dbus::MessageReader reader(response);
dbus::ObjectPath new_object_path;
if (!reader.PopObjectPath(&new_object_path)) {
LOG(ERROR) << "Failed to read object path from response.";
Finish(base::unexpected(ResponseError::kInvalidMethodResponse));
return;
}
if (reader.HasMoreData()) {
LOG(ERROR) << "Unexpected extra data in response.";
Finish(base::unexpected(ResponseError::kInvalidMethodResponse));
return;
}
// If there's no error reading the response, the response signal handler will
// call Finish(), so Finish() should not be called past this point.
if (new_object_path == request_object_path_) {
return;
}
// Prior to version 0.9 of xdg-desktop-portal, a race condition was possible
// where the signal would be emitted before the client connected to it. This
// was fixed by adding the "handle_token" key to the options dictionary. To
// maintain compatibility with older versions of xdg-desktop-portal, the
// spec recommends clients check the returned object path matches their
// expectation, and reconnect the signal handler to the returned object path
// if not. In the wild, nearly all xdg-desktop-portal implementations are
// version 0.9 or later.
bus_->RemoveObjectProxy(portal_service_name_, request_object_path_,
base::DoNothing());
request_object_path_ = new_object_path;
auto* new_request_proxy =
bus_->GetObjectProxy(portal_service_name_, request_object_path_);
new_request_proxy->ConnectToSignal(
kRequestInterface, kSignalResponse,
base::BindRepeating(&Request::OnResponseSignal,
weak_ptr_factory_.GetWeakPtr()),
base::BindOnce(&Request::OnSignalConnected,
weak_ptr_factory_.GetWeakPtr()));
}
void Request::OnResponseSignal(dbus::Signal* signal) {
dbus::MessageReader reader(signal);
uint32_t response_code = 0;
if (!reader.PopUint32(&response_code)) {
LOG(ERROR) << "Failed to read response code from signal.";
Finish(base::unexpected(ResponseError::kInvalidSignalResponse));
return;
}
switch (static_cast<ResponseCode>(response_code)) {
case ResponseCode::kSuccess:
break;
case ResponseCode::kUserCancelled:
LOG(ERROR) << "Request cancelled by user.";
Finish(base::unexpected(ResponseError::kRequestCancelledByUser));
return;
case ResponseCode::kOther:
LOG(ERROR) << "Request ended (non-user cancelled).";
Finish(base::unexpected(ResponseError::kRequestCancelledOther));
return;
default:
LOG(ERROR) << "Invalid request response code: " << response_code;
Finish(base::unexpected(ResponseError::kInvalidResponseCode));
return;
}
DbusDictionary results;
if (!results.Read(&reader)) {
LOG(ERROR) << "Failed to read results dictionary.";
Finish(base::unexpected(ResponseError::kInvalidSignalResponse));
return;
}
Finish(base::ok(std::move(results)));
}
void Request::OnSignalConnected(const std::string& interface_name,
const std::string& signal_name,
bool success) {
if (!success) {
LOG(ERROR) << "Failed to connect to signal: " << interface_name << "."
<< signal_name;
Finish(base::unexpected(ResponseError::kSignalConnectionFailed));
}
}
void Request::Finish(base::expected<DbusDictionary, ResponseError>&& result) {
if (!callback_) {
return;
}
bus_->RemoveObjectProxy(portal_service_name_, request_object_path_,
base::DoNothing());
bus_.reset();
weak_ptr_factory_.InvalidateWeakPtrs();
std::move(callback_).Run(std::move(result));
// `this` may be destroyed by the callback.
}
} // namespace dbus_xdg
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