Add an X11EventFilter class

This class provides an event filter, specific to an event type, that
can be registered with Workspace to filter events.

CMakeLists.txt

@@ -373,6 +373,7 @@ set(kwin_KDEINIT_SRCS
    paintredirector.cpp
    virtualdesktops.cpp
    xcbutils.cpp
+   x11eventfilter.cpp
     scripting/scripting.cpp
     scripting/workspace_wrapper.cpp
     scripting/meta.cpp

events.cpp

@@ -60,6 +60,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "composite.h"
 #include "killwindow.h"
+#include "x11eventfilter.h"
 
 namespace KWin
 {
@@ -157,6 +158,25 @@ QVector<QByteArray> s_xcbEerrors({
     QByteArrayLiteral("BadLength"),
     QByteArrayLiteral("BadImplementation"),
     QByteArrayLiteral("Unknown")});
+
+
+void Workspace::registerEventFilter(X11EventFilter *filter)
+{
+    if (filter->eventType() == XCB_GE_GENERIC)
+        m_genericEventFilters.append(filter);
+    else
+        m_eventFilters.append(filter);
+}
+
+void Workspace::unregisterEventFilter(X11EventFilter *filter)
+{
+    if (filter->eventType() == XCB_GE_GENERIC)
+        m_genericEventFilters.removeOne(filter);
+    else
+        m_eventFilters.removeOne(filter);
+}
+
+
 /*!
   Handles workspace specific XCB event
  */
@@ -192,6 +212,23 @@ bool Workspace::workspaceEvent(xcb_generic_event_t *e)
         }
         return false;
     }
+
+    if (eventType == XCB_GE_GENERIC) {
+        xcb_ge_generic_event_t *ge = reinterpret_cast<xcb_ge_generic_event_t *>(e);
+
+        foreach (X11EventFilter *filter, m_genericEventFilters) {
+            if (filter->extension() == ge->extension && filter->genericEventType() == ge->event_type && filter->event(e)) {
+                return true;
+            }
+        }
+    } else {
+        foreach (X11EventFilter *filter, m_eventFilters) {
+            if (filter->eventType() == eventType && filter->event(e)) {
+                return true;
+            }
+        }
+    }
+
     if (effects && static_cast< EffectsHandlerImpl* >(effects)->hasKeyboardGrab()
             && (eventType == XCB_KEY_PRESS || eventType == XCB_KEY_RELEASE))
         return false; // let Qt process it, it'll be intercepted again in eventFilter()

workspace.h

@@ -55,6 +55,7 @@ class KillWindow;
 class ShortcutDialog;
 class UserActionsMenu;
 class Compositor;
+class X11EventFilter;
 enum class Predicate;
 
 class Workspace : public QObject, public KDecorationDefines
@@ -327,6 +328,9 @@ public:
      **/
     bool compositing() const;
 
+    void registerEventFilter(X11EventFilter *filter);
+    void unregisterEventFilter(X11EventFilter *filter);
+
 public Q_SLOTS:
     void performWindowOperation(KWin::Client* c, KDecorationDefines::WindowOperation op);
     // Keybindings
@@ -574,6 +578,9 @@ private:
 
     QScopedPointer<KillWindow> m_windowKiller;
 
+    QList<X11EventFilter *> m_eventFilters;
+    QList<X11EventFilter *> m_genericEventFilters;
+
 private:
     friend bool performTransiencyCheck();
     friend Workspace *workspace();

x11eventfilter.cpp

@@ -0,0 +1,38 @@
+/********************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+Copyright (C) 2014 Fredrik Höglund <fredrik@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 "x11eventfilter.h"
+#include "workspace.h"
+
+namespace KWin
+{
+
+X11EventFilter::X11EventFilter(int eventType, int opcode, int genericEventType)
+    : m_eventType(eventType), m_extension(opcode), m_genericEventType(genericEventType)
+{
+    Workspace::self()->registerEventFilter(this);
+}
+
+X11EventFilter::~X11EventFilter()
+{
+    Workspace::self()->unregisterEventFilter(this);
+}
+
+}

x11eventfilter.h

@@ -0,0 +1,76 @@
+/********************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+Copyright (C) 2014 Fredrik Höglund <fredrik@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/>.
+*********************************************************************/
+
+#ifndef X11EVENTFILTER_H
+#define X11EVENTFILTER_H
+
+#include <xcb/xcb.h>
+
+namespace KWin
+{
+
+class X11EventFilter
+{
+public:
+    /**
+     * Creates an event filter for the given event type.
+     */
+    X11EventFilter(int eventType, int opcode = 0, int genericEventType = 0);
+
+    /**
+     * Destroys the event filter.
+     */
+    virtual ~X11EventFilter();
+
+    /**
+     * Returns the type of events to filter.
+     */
+    int eventType() const { return m_eventType; }
+
+    /**
+     * Returns the major opcode of the extension.
+     *
+     * Only used when the event type is XCB_GE_GENERIC.
+     */
+    int extension() const { return m_extension; }
+
+    /**
+     * Returns the type of generic events to filter.
+     *
+     * Only used when the event type is XCB_GE_GENERIC.
+     */
+    int genericEventType() const { return m_genericEventType; }
+
+    /**
+     * This method is called for every event of the filtered type.
+     *
+     * Return true to accept the event and stop further processing, and false otherwise.
+     */
+    virtual bool event(xcb_generic_event_t *event) = 0;
+
+private:
+    int m_eventType;
+    int m_extension;
+    int m_genericEventType;
+};
+
+} // namespace KWin
+
+#endif