Differential D17369 Diff 48429 plugins/platforms/x11/common/ge_event_mem_mover.h

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plugins/platforms/x11/common/ge_event_mem_mover.h

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		1		/********************************************************************
		2		KWin - the KDE window manager
		3		This file is part of the KDE project.
		4
		5		Copyright (C) 2018 Martin Flöser <mgraesslin@kde.org>
		6
		7		This program is free software; you can redistribute it and/or modify
		8		it under the terms of the GNU General Public License as published by
		9		the Free Software Foundation; either version 2 of the License, or
		10		(at your option) any later version.
		11
		12		This program is distributed in the hope that it will be useful,
		13		but WITHOUT ANY WARRANTY; without even the implied warranty of
		14		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		15		GNU General Public License for more details.
		16
		17		You should have received a copy of the GNU General Public License
		18		along with this program. If not, see <http://www.gnu.org/licenses/>.
		19		*********************************************************************/
		20		#pragma once
		21
		22		#include <xcb/xcb.h>
		23
		24		#include <string.h>
		25
		26		namespace KWin
		27		{
		28
		29		class GeEventMemMover
		30		{
		31		public:
		32		GeEventMemMover(xcb_generic_event_t *event)
		33		: m_event(reinterpret_cast<xcb_ge_generic_event_t *>(event))
		34		{
		35		// xcb event structs contain stuff that wasn't on the wire, the full_sequence field
		36		// adds an extra 4 bytes and generic events cookie data is on the wire right after the standard 32 bytes.
		37		// Move this data back to have the same layout in memory as it was on the wire
		38		// and allow casting, overwriting the full_sequence field.
		39		memmove((char) m_event + 32, (char) m_event + 36, m_event->length * 4);
		40		}
		41		~GeEventMemMover()
		42		{
		43		// move memory layout back, so that Qt can do the same without breaking
		44		memmove((char) m_event + 36, (char ) m_event + 32, m_event->length * 4);
		45		}
		46
		47		xcb_ge_generic_event_t *operator->() const {
		48		return m_event;
		49		}
		50
		51		private:
		52		xcb_ge_generic_event_t *m_event;
		53		};
		54
		55		}