include/dbus-c++/pendingcall.h

/*
 *
 *  D-Bus++ - C++ bindings for D-Bus
 *
 *  Copyright (C) 2005-2007  Paolo Durante <shackan@gmail.com>
 *
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */


#ifndef __DBUSXX_PENDING_CALL_H
#define __DBUSXX_PENDING_CALL_H

#include "api.h"
#include "util.h"
#include "message.h"

namespace DBus {

class Connection;
class PendingCall;

typedef Slot<void, PendingCall *> AsyncReplyHandler;

class DXXAPI PendingCall
{
public:

	struct Private;

	PendingCall(Private *);

	PendingCall(const PendingCall &);

	virtual ~PendingCall();

	PendingCall &operator = (const PendingCall &);

	/*!
	 * \brief Checks whether the pending call has received a reply yet, or not.
	 *
	 * \return true If a reply has been received.
	 */
	bool completed();
	
	/*!
	 * \brief Cancels the pending call, such that any reply or error received will 
	 *        just be ignored.
	 *
	 * Drops the dbus library's internal reference to the DBusPendingCall so will 
	 * free the call if nobody else is holding a reference. However you usually 
	 * get a reference from Connection::send_async() so probably your app 
	 * owns a ref also.
	 *
	 * Note that canceling a pending call will not simulate a timed-out call; if a 
	 * call times out, then a timeout error reply is received. If you cancel the 
	 * call, no reply is received unless the the reply was already received before 
	 * you cancelled.
	 */
	void cancel();

	/*!
	 * \brief Block until the pending call is completed.
	 *
	 * The blocking is as with Connection::send_blocking(); it
	 * does not enter the main loop or process other messages, it simply waits for
	 * the reply in question.
	 *
	 * If the pending call is already completed, this function returns immediately.
	 */
	void block();

	/*!
	 * \brief Stores a pointer on a PendingCall, along with an optional function to 
	 *        be used for freeing the data when the data is set again, or when the
	 *        pending call is finalized.
	 *
	 * The slot is allocated automatically.
	 *
	 * \param data The data to store.
	 * \throw ErrorNoMemory
	 */
	void data( void* data );

	/*!
	 * \brief Retrieves data previously set with dbus_pending_call_set_data().
	 *
	 * The slot must still be allocated (must not have been freed).
	 *
	 * \return The data, or NULL if not found.
	 */
	void *data();

	/*!
	 * \return The reply handler slot.
	 */
	AsyncReplyHandler& reply_handler();

	/*!
	 * \brief Sets a callback to handle an asynchronous reply to a method
	 * invocation.
	 *
	 * If the pending call has not been cancelled, the supplied callback will
	 * be invoked when a reply is received. The callback is a templated
	 * class, where the two template arguments are the type of the single
	 * argument taken by the handler function, and the return type of that
	 * function.
	 *
	 * \param handler The callback.
	 */
	void reply_handler(const AsyncReplyHandler& handler);

	/*!
	 * \brief Gets the reply message
	 *
	 * Ownership of the reply message passes to the caller. This function can only 
	 * be called once per pending call, since the reply message is tranferred to 
	 * the caller.
	 *
	 * \return The reply Message.
	 * \throw ErrorNoReply
	 */
	Message steal_reply();

private:

	RefPtrI<Private> _pvt;

friend struct Private;
friend class Connection;
};

} /* namespace DBus */

#endif//__DBUSXX_PENDING_CALL_H