kwin/plugins/qpa/backingstore.cpp
Martin Flöser 962a2e39ee [qpa] Prevent crash due to Surface getting null
Summary:
This is a regression due to changes in Breeze to support Qt 5.8+ behavior
change. KWin's own QPA operates like < Qt 5.7 and breeze was programmed
against that. Due to that it can happen now that Breeze hits code paths
in which KWin does not have a surface.

To trigger one only needed to open the user actions menu twice.

This change adds a test case which simulates the problem and fixes all
crashes happening in the code path.

Most likely shadows are now broken for KWin's own windows, this change is
only to prevent the crash and thus is for 5.10 branch, while shadow
fixing will go to master branch.

BUG: 382063
FIXED-IN: 5.10.4

Test Plan: New test case

Reviewers: #kwin, #plasma

Subscribers: plasma-devel, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D6533
2017-07-06 19:14:15 +02:00

119 lines
3.4 KiB
C++

/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2015 Martin Gräßlin <mgraesslin@kde.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#include "window.h"
#include "backingstore.h"
#include "../../wayland_server.h"
#include <KWayland/Client/connection_thread.h>
#include <KWayland/Client/buffer.h>
#include <KWayland/Client/shm_pool.h>
#include <KWayland/Client/surface.h>
namespace KWin
{
namespace QPA
{
BackingStore::BackingStore(QWindow *w, KWayland::Client::ShmPool *shm)
: QPlatformBackingStore(w)
, m_shm(shm)
, m_backBuffer(QSize(), QImage::Format_ARGB32_Premultiplied)
{
QObject::connect(m_shm, &KWayland::Client::ShmPool::poolResized,
[this] {
if (!m_buffer) {
return;
}
auto b = m_buffer.toStrongRef();
if (!b->isUsed()){
return;
}
const QSize size = m_backBuffer.size();
m_backBuffer = QImage(b->address(), size.width(), size.height(), QImage::Format_ARGB32_Premultiplied);
}
);
}
BackingStore::~BackingStore() = default;
QPaintDevice *BackingStore::paintDevice()
{
return &m_backBuffer;
}
void BackingStore::resize(const QSize &size, const QRegion &staticContents)
{
Q_UNUSED(staticContents)
m_size = size;
if (!m_buffer) {
return;
}
m_buffer.toStrongRef()->setUsed(false);
m_buffer.clear();
}
void BackingStore::flush(QWindow *window, const QRegion &region, const QPoint &offset)
{
Q_UNUSED(region)
Q_UNUSED(offset)
auto s = static_cast<Window *>(window->handle())->surface();
if (!s) {
return;
}
s->attachBuffer(m_buffer);
// TODO: proper damage region
s->damage(QRect(QPoint(0, 0), m_backBuffer.size()));
s->commit(KWayland::Client::Surface::CommitFlag::None);
waylandServer()->internalClientConection()->flush();
waylandServer()->dispatch();
}
void BackingStore::beginPaint(const QRegion&)
{
if (m_buffer) {
auto b = m_buffer.toStrongRef();
if (b->isReleased()) {
// we can re-use this buffer
b->setReleased(false);
return;
} else {
// buffer is still in use, get a new one
b->setUsed(false);
}
}
auto oldBuffer = m_buffer.toStrongRef();
m_buffer.clear();
m_buffer = m_shm->getBuffer(m_size, m_size.width() * 4);
if (!m_buffer) {
m_backBuffer = QImage();
return;
}
auto b = m_buffer.toStrongRef();
b->setUsed(true);
m_backBuffer = QImage(b->address(), m_size.width(), m_size.height(), QImage::Format_ARGB32_Premultiplied);
if (oldBuffer) {
b->copy(oldBuffer->address());
} else {
m_backBuffer.fill(Qt::transparent);
}
}
}
}