Move XRandR event filter into XRandRScreens

Summary:
The code in events.cpp was problematic as it was called in a Wayland
session. So KWin changed outputs, this gets mirrored to XWayland and
then KWin reacted on the XRandR event and might have even changed the
refresh rate due to that - bad idea.

This change moves the code into the already existing X11EventFilter for
XRandR events in XRandRScreens.

Test Plan: Run kwin_x11 in gdb on Xephyr, breakpoint in new code and triggered XRandR event

Reviewers: #kwin, #plasma

Subscribers: plasma-devel, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D7654

autotests/mock_workspace.h

@@ -51,6 +51,10 @@ public:
     void registerEventFilter(X11EventFilter *filter);
     void unregisterEventFilter(X11EventFilter *filter);
 
+    bool compositing() const {
+        return false;
+    }
+
     static Workspace *self();
 
 Q_SIGNALS:

events.cpp

@@ -81,8 +81,6 @@ typedef struct xcb_ge_generic_event_t {
 namespace KWin
 {
 
-extern int currentRefreshRate();
-
 // ****************************************
 // Workspace
 // ****************************************
@@ -428,29 +426,7 @@ bool Workspace::workspaceEvent(xcb_generic_event_t *e)
     case XCB_FOCUS_OUT:
         return true; // always eat these, they would tell Qt that KWin is the active app
     default:
-        if (eventType == Xcb::Extensions::self()->randrNotifyEvent() && Xcb::Extensions::self()->isRandrAvailable()) {
-            auto *event = reinterpret_cast<xcb_randr_screen_change_notify_event_t*>(e);
-            xcb_screen_t *screen = defaultScreen();
-            if (event->rotation & (XCB_RANDR_ROTATION_ROTATE_90 | XCB_RANDR_ROTATION_ROTATE_270)) {
-                screen->width_in_pixels = event->height;
-                screen->height_in_pixels = event->width;
-                screen->width_in_millimeters = event->mheight;
-                screen->height_in_millimeters = event->mwidth;
-            } else {
-                screen->width_in_pixels = event->width;
-                screen->height_in_pixels = event->height;
-                screen->width_in_millimeters = event->mwidth;
-                screen->height_in_millimeters = event->mheight;
-            }
-            if (compositing()) {
-                // desktopResized() should take care of when the size or
-                // shape of the desktop has changed, but we also want to
-                // catch refresh rate changes
-                if (m_compositor->xrrRefreshRate() != currentRefreshRate())
-                    m_compositor->setCompositeResetTimer(0);
-            }
-
-        } else if (eventType == Xcb::Extensions::self()->syncAlarmNotifyEvent() && Xcb::Extensions::self()->isSyncAvailable()) {
+        if (eventType == Xcb::Extensions::self()->syncAlarmNotifyEvent() && Xcb::Extensions::self()->isSyncAvailable()) {
             for (Client *c : clients)
                 c->syncEvent(reinterpret_cast< xcb_sync_alarm_notify_event_t* >(e));
             for (Client *c : desktops)

options.cpp

@@ -42,6 +42,11 @@ namespace KWin
 #ifndef KCMRULES
 
 int currentRefreshRate()
+{
+    return Options::currentRefreshRate();
+}
+
+int Options::currentRefreshRate()
 {
     int rate = -1;
     QString syncScreenName(QLatin1String("primary screen"));

options.h

@@ -783,6 +783,8 @@ public:
     bool loadCompositingConfig(bool force);
     void reparseConfiguration();
 
+    static int currentRefreshRate();
+
     //----------------------
 Q_SIGNALS:
     // for properties

plugins/platforms/x11/standalone/screens_xrandr.cpp

@@ -18,6 +18,9 @@ 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 "screens_xrandr.h"
+#include "composite.h"
+#include "options.h"
+#include "workspace.h"
 #include "xcbutils.h"
 
 
@@ -185,6 +188,29 @@ bool XRandRScreens::event(xcb_generic_event_t *event)
     Q_ASSERT((event->response_type & ~0x80) == Xcb::Extensions::self()->randrNotifyEvent());
     // let's try to gather a few XRandR events, unlikely that there is just one
     startChangedTimer();
+
+    // update default screen
+    auto *xrrEvent = reinterpret_cast<xcb_randr_screen_change_notify_event_t*>(event);
+    xcb_screen_t *screen = defaultScreen();
+    if (xrrEvent->rotation & (XCB_RANDR_ROTATION_ROTATE_90 | XCB_RANDR_ROTATION_ROTATE_270)) {
+        screen->width_in_pixels = xrrEvent->height;
+        screen->height_in_pixels = xrrEvent->width;
+        screen->width_in_millimeters = xrrEvent->mheight;
+        screen->height_in_millimeters = xrrEvent->mwidth;
+    } else {
+        screen->width_in_pixels = xrrEvent->width;
+        screen->height_in_pixels = xrrEvent->height;
+        screen->width_in_millimeters = xrrEvent->mwidth;
+        screen->height_in_millimeters = xrrEvent->mheight;
+    }
+    if (workspace()->compositing()) {
+        // desktopResized() should take care of when the size or
+        // shape of the desktop has changed, but we also want to
+        // catch refresh rate changes
+        if (Compositor::self()->xrrRefreshRate() != Options::currentRefreshRate())
+            Compositor::self()->setCompositeResetTimer(0);
+    }
+
     return false;
 }