1 files changed, 30 insertions, 18 deletions

diff --git a/src/plugins/platforms/xcb/qxcbwindowsurface.cpp b/src/plugins/platforms/xcb/qxcbwindowsurface.cpp
index 4fcd207df3..63378515cc 100644
--- a/src/plugins/platforms/xcb/qxcbwindowsurface.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindowsurface.cpp
@@ -52,6 +52,7 @@
 #include <sys/shm.h>
 
 #include <stdio.h>
+#include <errno.h>
 
 #include <qdebug.h>
 #include <qpainter.h>
@@ -97,9 +98,16 @@ QXcbShmImage::QXcbShmImage(QXcbScreen *screen, const QSize &size, uint depth, QI
                                           ~0,
                                           0);
 
-    m_shm_info.shmid = shmget (IPC_PRIVATE,
-          m_xcb_image->stride * m_xcb_image->height, IPC_CREAT|0777);
+    const int segmentSize = m_xcb_image->stride * m_xcb_image->height;
+    if (!segmentSize)
+        return;
 
+    int id = shmget(IPC_PRIVATE, segmentSize, IPC_CREAT | 0777);
+    if (id == -1)
+        qWarning("QXcbShmImage: shmget() failed (%d) for size %d (%dx%d)",
+                 errno, segmentSize, size.width(), size.height());
+    else
+        m_shm_info.shmid = id;
     m_shm_info.shmaddr = m_xcb_image->data = (quint8 *)shmat (m_shm_info.shmid, 0, 0);
     m_shm_info.shmseg = xcb_generate_id(xcb_connection());
 
@@ -117,10 +125,17 @@ QXcbShmImage::QXcbShmImage(QXcbScreen *screen, const QSize &size, uint depth, QI
 
 void QXcbShmImage::destroy()
 {
-    Q_XCB_CALL(xcb_shm_detach(xcb_connection(), m_shm_info.shmseg));
+    const int segmentSize = m_xcb_image ? (m_xcb_image->stride * m_xcb_image->height) : 0;
+    if (segmentSize)
+        Q_XCB_CALL(xcb_shm_detach(xcb_connection(), m_shm_info.shmseg));
+
     xcb_image_destroy(m_xcb_image);
-    shmdt(m_shm_info.shmaddr);
-    shmctl(m_shm_info.shmid, IPC_RMID, 0);
+
+    if (segmentSize) {
+        shmdt(m_shm_info.shmaddr);
+        shmctl(m_shm_info.shmid, IPC_RMID, 0);
+    }
+
     if (m_gc)
         Q_XCB_CALL(xcb_free_gc(xcb_connection(), m_gc));
 }
@@ -168,12 +183,12 @@ void QXcbShmImage::preparePaint(const QRegion &region)
     }
 }
 
-QXcbWindowSurface::QXcbWindowSurface(QWidget *widget, bool setDefaultSurface)
-    : QWindowSurface(widget, setDefaultSurface)
+QXcbWindowSurface::QXcbWindowSurface(QWindow *window, bool setDefaultSurface)
+    : QWindowSurface(window, setDefaultSurface)
     , m_image(0)
     , m_syncingResize(false)
 {
-    QXcbScreen *screen = static_cast<QXcbScreen *>(QPlatformScreen::platformScreenForWidget(widget));
+    QXcbScreen *screen = static_cast<QXcbScreen *>(QPlatformScreen::platformScreenForWindow(window));
     setConnection(screen->connection());
 }
 
@@ -206,7 +221,7 @@ void QXcbWindowSurface::endPaint(const QRegion &)
 {
 }
 
-void QXcbWindowSurface::flush(QWidget *widget, const QRegion &region, const QPoint &offset)
+void QXcbWindowSurface::flush(QWindow *window, const QRegion &region, const QPoint &offset)
 {
     QRect bounds = region.boundingRect();
 
@@ -215,14 +230,11 @@ void QXcbWindowSurface::flush(QWidget *widget, const QRegion &region, const QPoi
 
     Q_XCB_NOOP(connection());
 
-    QXcbWindow *window = static_cast<QXcbWindow *>(widget->window()->platformWindow());
-
-    extern QWidgetData* qt_widget_data(QWidget *);
-    QPoint widgetOffset = qt_qwidget_data(widget)->wrect.topLeft();
+    QXcbWindow *platformWindow = static_cast<QXcbWindow *>(window->handle());
 
     QVector<QRect> rects = region.rects();
     for (int i = 0; i < rects.size(); ++i)
-        m_image->put(window->window(), rects.at(i).topLeft() - widgetOffset, rects.at(i).translated(offset));
+        m_image->put(platformWindow->xcb_window(), rects.at(i).topLeft(), rects.at(i).translated(offset));
 
     Q_XCB_NOOP(connection());
 
@@ -230,7 +242,7 @@ void QXcbWindowSurface::flush(QWidget *widget, const QRegion &region, const QPoi
         xcb_flush(xcb_connection());
         connection()->sync();
         m_syncingResize = false;
-        window->updateSyncRequestCounter();
+        platformWindow->updateSyncRequestCounter();
     }
 }
 
@@ -242,8 +254,8 @@ void QXcbWindowSurface::resize(const QSize &size)
     Q_XCB_NOOP(connection());
     QWindowSurface::resize(size);
 
-    QXcbScreen *screen = static_cast<QXcbScreen *>(QPlatformScreen::platformScreenForWidget(window()));
-    QXcbWindow* win = static_cast<QXcbWindow *>(window()->platformWindow());
+    QXcbScreen *screen = static_cast<QXcbScreen *>(QPlatformScreen::platformScreenForWindow(window()));
+    QXcbWindow* win = static_cast<QXcbWindow *>(window()->handle());
 
     delete m_image;
     m_image = new QXcbShmImage(screen, size, win->depth(), win->format());
@@ -256,7 +268,7 @@ extern void qt_scrollRectInImage(QImage &img, const QRect &rect, const QPoint &o
 
 bool QXcbWindowSurface::scroll(const QRegion &area, int dx, int dy)
 {
-    if (m_image->image()->isNull())
+    if (!m_image || m_image->image()->isNull())
         return false;
 
     m_image->preparePaint(area);