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// 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 "mojo/shell/dbus_service_loader_linux.h"
#include <string>
#include "base/command_line.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/task_runner_util.h"
#include "base/threading/thread_restrictions.h"
#include "dbus/bus.h"
#include "dbus/file_descriptor.h"
#include "dbus/message.h"
#include "dbus/object_path.h"
#include "dbus/object_proxy.h"
#include "mojo/common/channel_init.h"
#include "mojo/dbus/dbus_external_service.h"
#include "mojo/embedder/platform_channel_pair.h"
#include "mojo/public/cpp/bindings/allocation_scope.h"
#include "mojo/public/cpp/bindings/interface.h"
#include "mojo/public/cpp/bindings/remote_ptr.h"
#include "mojo/shell/context.h"
#include "mojo/shell/external_service.mojom.h"
#include "mojo/shell/keep_alive.h"
namespace mojo {
namespace shell {
// Manages the connection to a single externally-running service.
class DBusServiceLoader::LoadContext : public mojo::ExternalServiceHost {
public:
// Kicks off the attempt to bootstrap a connection to the externally-running
// service specified by url_.
// Creates a MessagePipe and passes one end over DBus to the service. Then,
// calls ExternalService::Activate(ShellHandle) over the now-shared pipe.
LoadContext(DBusServiceLoader* loader,
const scoped_refptr<dbus::Bus>& bus,
const GURL& url,
ScopedShellHandle shell_handle)
: loader_(loader),
bus_(bus),
service_dbus_proxy_(NULL),
url_(url),
shell_handle_(shell_handle.Pass()),
keep_alive_(loader->context_) {
base::PostTaskAndReplyWithResult(
loader_->context_->task_runners()->io_runner(),
FROM_HERE,
base::Bind(&LoadContext::CreateChannelOnIOThread,
base::Unretained(this)),
base::Bind(&LoadContext::ConnectChannel, base::Unretained(this)));
}
virtual ~LoadContext() {
}
private:
// Sets up a pipe to share with the externally-running service and returns
// the endpoint that should be sent over DBus.
// The FD for the endpoint must be validated on an IO thread.
scoped_ptr<dbus::FileDescriptor> CreateChannelOnIOThread() {
base::ThreadRestrictions::AssertIOAllowed();
CHECK(bus_->Connect());
CHECK(bus_->SetUpAsyncOperations());
embedder::PlatformChannelPair channel_pair;
channel_init_.reset(new common::ChannelInit);
mojo::ScopedMessagePipeHandle bootstrap_message_pipe =
channel_init_->Init(channel_pair.PassServerHandle().release().fd,
loader_->context_->task_runners()->io_runner());
CHECK(bootstrap_message_pipe.is_valid());
external_service_.reset(
mojo::ScopedExternalServiceHandle::From(bootstrap_message_pipe.Pass()),
this);
scoped_ptr<dbus::FileDescriptor> client_fd(new dbus::FileDescriptor);
client_fd->PutValue(channel_pair.PassClientHandle().release().fd);
client_fd->CheckValidity(); // Must be run on an IO thread.
return client_fd.Pass();
}
// Sends client_fd over to the externally-running service. If that
// attempt is successful, the service will then be "activated" by
// sending it a ShellHandle.
void ConnectChannel(scoped_ptr<dbus::FileDescriptor> client_fd) {
size_t first_slash = url_.path().find_first_of('/');
DCHECK_NE(first_slash, std::string::npos);
const std::string service_name = url_.path().substr(0, first_slash);
const std::string object_path = url_.path().substr(first_slash);
service_dbus_proxy_ =
bus_->GetObjectProxy(service_name, dbus::ObjectPath(object_path));
dbus::MethodCall call(kMojoDBusInterface, kMojoDBusConnectMethod);
dbus::MessageWriter writer(&call);
writer.AppendFileDescriptor(*client_fd.get());
// TODO(cmasone): handle errors!
service_dbus_proxy_->CallMethod(
&call,
dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
base::Bind(&LoadContext::ActivateService, base::Unretained(this)));
}
// Sends a ShellHandle over to the now-connected externally-running service,
// using the Mojo ExternalService API.
void ActivateService(dbus::Response* response) {
mojo::AllocationScope scope;
external_service_->Activate(
mojo::ScopedMessagePipeHandle(
mojo::MessagePipeHandle(shell_handle_.release().value())));
}
// Should the ExternalService disappear completely, destroy connection state.
// NB: This triggers off of the service disappearing from
// DBus. Perhaps there's a way to watch at the Mojo layer instead,
// and that would be superior?
void HandleNameOwnerChanged(const std::string& old_owner,
const std::string& new_owner) {
DCHECK(loader_->context_->task_runners()->ui_runner()->
BelongsToCurrentThread());
if (new_owner.empty()) {
loader_->context_->task_runners()->ui_runner()->PostTask(
FROM_HERE,
base::Bind(&DBusServiceLoader::ForgetService,
base::Unretained(loader_), url_));
}
}
DBusServiceLoader* const loader_;
scoped_refptr<dbus::Bus> bus_;
dbus::ObjectProxy* service_dbus_proxy_; // Owned by bus_;
const GURL url_;
ScopedShellHandle shell_handle_;
KeepAlive keep_alive_;
scoped_ptr<common::ChannelInit> channel_init_;
mojo::RemotePtr<mojo::ExternalService> external_service_;
DISALLOW_COPY_AND_ASSIGN(LoadContext);
};
DBusServiceLoader::DBusServiceLoader(Context* context) : context_(context) {
dbus::Bus::Options options;
options.bus_type = dbus::Bus::SESSION;
options.dbus_task_runner = context_->task_runners()->io_runner();
bus_ = new dbus::Bus(options);
}
DBusServiceLoader::~DBusServiceLoader() {
DCHECK(url_to_load_context_.empty());
}
void DBusServiceLoader::LoadService(ServiceManager* manager,
const GURL& url,
ScopedShellHandle service_handle) {
DCHECK(url.SchemeIs("dbus"));
DCHECK(url_to_load_context_.find(url) == url_to_load_context_.end());
url_to_load_context_[url] =
new LoadContext(this, bus_, url, service_handle.Pass());
}
void DBusServiceLoader::OnServiceError(ServiceManager* manager,
const GURL& url) {
// TODO(cmasone): Anything at all in this method here.
}
void DBusServiceLoader::ForgetService(const GURL& url) {
DCHECK(context_->task_runners()->ui_runner()->BelongsToCurrentThread());
DVLOG(2) << "Forgetting service (url: " << url << ")";
LoadContextMap::iterator it = url_to_load_context_.find(url);
DCHECK(it != url_to_load_context_.end()) << url;
LoadContext* doomed = it->second;
url_to_load_context_.erase(it);
delete doomed;
}
} // namespace shell
} // namespace mojo
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