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// Copyright (c) 2012 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.
#ifndef DBUS_EXPORTED_OBJECT_H_
#define DBUS_EXPORTED_OBJECT_H_
#include <dbus/dbus.h>
#include <map>
#include <string>
#include <utility>
#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/waitable_event.h"
#include "base/threading/platform_thread.h"
#include "base/time/time.h"
#include "dbus/dbus_export.h"
#include "dbus/object_path.h"
namespace dbus {
class Bus;
class MethodCall;
class Response;
class Signal;
// ExportedObject is used to export objects and methods to other D-Bus
// clients.
//
// ExportedObject is a ref counted object, to ensure that |this| of the
// object is alive when callbacks referencing |this| are called.
class CHROME_DBUS_EXPORT ExportedObject
: public base::RefCountedThreadSafe<ExportedObject> {
public:
// Client code should use Bus::GetExportedObject() instead of this
// constructor.
ExportedObject(Bus* bus, const ObjectPath& object_path);
// Called to send a response from an exported method. |response| is the
// response message. Callers should pass NULL in the event of an error that
// prevents the sending of a response.
typedef base::Callback<void (scoped_ptr<Response> response)> ResponseSender;
// Called when an exported method is called. |method_call| is the request
// message. |sender| is the callback that's used to send a response.
//
// |method_call| is owned by ExportedObject, hence client code should not
// delete |method_call|.
typedef base::Callback<void (MethodCall* method_call, ResponseSender sender)>
MethodCallCallback;
// Called when method exporting is done.
// |success| indicates whether exporting was successful or not.
typedef base::Callback<void (const std::string& interface_name,
const std::string& method_name,
bool success)>
OnExportedCallback;
// Exports the method specified by |interface_name| and |method_name|,
// and blocks until exporting is done. Returns true on success.
//
// |method_call_callback| will be called in the origin thread, when the
// exported method is called. As it's called in the origin thread,
// |method_callback| can safely reference objects in the origin thread
// (i.e. UI thread in most cases).
//
// IMPORTANT NOTE: You should export all methods before requesting a
// service name by Bus::RequestOwnership/AndBlock(). If you do it in the
// wrong order (i.e. request a service name then export methods), there
// will be a short time period where your service is unable to respond to
// method calls because these methods aren't yet exposed. This race is a
// real problem as clients may start calling methods of your service as
// soon as you acquire a service name, by watching the name owner change.
//
// BLOCKING CALL.
virtual bool ExportMethodAndBlock(const std::string& interface_name,
const std::string& method_name,
MethodCallCallback method_call_callback);
// Requests to export the method specified by |interface_name| and
// |method_name|. See Also ExportMethodAndBlock().
//
// |on_exported_callback| is called when the method is exported or
// failed to be exported, in the origin thread.
//
// Must be called in the origin thread.
virtual void ExportMethod(const std::string& interface_name,
const std::string& method_name,
MethodCallCallback method_call_callback,
OnExportedCallback on_exported_callback);
// Requests to send the signal from this object. The signal will be sent
// synchronously if this method is called from the message loop in the D-Bus
// thread and asynchronously otherwise.
virtual void SendSignal(Signal* signal);
// Unregisters the object from the bus. The Bus object will take care of
// unregistering so you don't have to do this manually.
//
// BLOCKING CALL.
virtual void Unregister();
protected:
// This is protected, so we can define sub classes.
virtual ~ExportedObject();
private:
friend class base::RefCountedThreadSafe<ExportedObject>;
// Helper function for ExportMethod().
void ExportMethodInternal(const std::string& interface_name,
const std::string& method_name,
MethodCallCallback method_call_callback,
OnExportedCallback exported_callback);
// Called when the object is exported.
void OnExported(OnExportedCallback on_exported_callback,
const std::string& interface_name,
const std::string& method_name,
bool success);
// Helper function for SendSignal().
void SendSignalInternal(base::TimeTicks start_time,
DBusMessage* signal_message);
// Registers this object to the bus.
// Returns true on success, or the object is already registered.
//
// BLOCKING CALL.
bool Register();
// Handles the incoming request messages and dispatches to the exported
// methods.
DBusHandlerResult HandleMessage(DBusConnection* connection,
DBusMessage* raw_message);
// Runs the method. Helper function for HandleMessage().
void RunMethod(MethodCallCallback method_call_callback,
scoped_ptr<MethodCall> method_call,
base::TimeTicks start_time);
// Callback invoked by service provider to send a response to a method call.
// Can be called immediately from a MethodCallCallback to implement a
// synchronous service or called later to implement an asynchronous service.
void SendResponse(base::TimeTicks start_time,
scoped_ptr<MethodCall> method_call,
scoped_ptr<Response> response);
// Called on completion of the method run from SendResponse().
// Takes ownership of |method_call| and |response|.
void OnMethodCompleted(scoped_ptr<MethodCall> method_call,
scoped_ptr<Response> response,
base::TimeTicks start_time);
// Called when the object is unregistered.
void OnUnregistered(DBusConnection* connection);
// Redirects the function call to HandleMessage().
static DBusHandlerResult HandleMessageThunk(DBusConnection* connection,
DBusMessage* raw_message,
void* user_data);
// Redirects the function call to OnUnregistered().
static void OnUnregisteredThunk(DBusConnection* connection,
void* user_data);
scoped_refptr<Bus> bus_;
ObjectPath object_path_;
bool object_is_registered_;
// The method table where keys are absolute method names (i.e. interface
// name + method name), and values are the corresponding callbacks.
typedef std::map<std::string, MethodCallCallback> MethodTable;
MethodTable method_table_;
};
} // namespace dbus
#endif // DBUS_EXPORTED_OBJECT_H_
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