touchui: First pass at XInput2 message pump.

base/message_pump_glib_x.cc

Index: base/message_pump_glib_x.cc
diff --git a/base/message_pump_glib_x.cc b/base/message_pump_glib_x.cc
index 675774ea5b5a8a8413b1b43265f855f66713bd1a..78c179933d00a7e5a70d0d94c3675fe7b9dd1379 100644
--- a/base/message_pump_glib_x.cc
+++ b/base/message_pump_glib_x.cc
@@ -5,7 +5,11 @@
 #include "base/message_pump_glib_x.h"
 
 #include <gdk/gdkx.h>
+#if defined(HAVE_XINPUT2)
+#include <X11/extensions/XInput2.h>
+#else
 #include <X11/Xlib.h>
+#endif
 
 #include "base/message_pump_glib_x_dispatch.h"
 
@@ -17,17 +21,61 @@ gboolean PlaceholderDispatch(GSource* source,
   return TRUE;
 }
 
+#if defined(HAVE_XINPUT2)
+
+// Setup XInput2 select for the GtkWidget.
+gboolean GtkWidgetRealizeCallback(GSignalInvocationHint* hint, guint nparams,
+                                  const GValue* pvalues, gpointer data) {
+  GtkWidget* widget = GTK_WIDGET(g_value_get_object(pvalues));
+  GdkWindow* window = widget->window;
+  base::MessagePumpGlibX* msgpump = static_cast<base::MessagePumpGlibX*>(data);
+
+  DCHECK(window);  // TODO(sad): Remove once determined if necessary.
+
+  // TODO(sad): Do we need to set a flag on |window| to make sure we don't
+  // select for the same GdkWindow multiple times? Does it matter?
+  msgpump->SetupXInput2ForXWindow(GDK_WINDOW_XID(window));
+
+  return true;
+}
+
+// We need to capture all the GDK windows that get created, and start
+// listening for XInput2 events. So we setup a callback to the 'realize'
+// signal for GTK+ widgets, so that whenever the signal triggers for any
+// GtkWidget, which means the GtkWidget should now have a GdkWindow, we can
+// setup XInput2 events for the GdkWindow.
+void SetupGtkWidgetRealizeNotifier(base::MessagePumpGlibX* msgpump) {
+  guint signal_id;
+  gpointer klass = g_type_class_ref(GTK_TYPE_WIDGET);
+
+  g_signal_parse_name("realize", GTK_TYPE_WIDGET, &signal_id, NULL, FALSE);
+  g_signal_add_emission_hook(signal_id, 0, GtkWidgetRealizeCallback,
+      static_cast<gpointer>(msgpump), NULL);
+
+  g_type_class_unref(klass);
+}
+
+#endif  // HAVE_XINPUT2
+
 }  // namespace
 
 namespace base {
 
 MessagePumpGlibX::MessagePumpGlibX() : base::MessagePumpForUI(),
+#if defined(HAVE_XINPUT2)
+    xiopcode_(-1),
+    masters_(),
+    slaves_(),
+#endif
     gdksource_(NULL),
     dispatching_event_(false),
     capture_x_events_(0),
     capture_gdk_events_(0) {
   gdk_event_handler_set(&EventDispatcherX, this, NULL);
 
+#if defined(HAVE_XINPUT2)
+  InitializeXInput2();
+#endif
   InitializeEventsToCapture();
 }
 
@@ -40,7 +88,11 @@ bool MessagePumpGlibX::RunOnce(GMainContext* context, bool block) {
   if (XPending(display)) {
     XEvent xev;
     XPeekEvent(display, &xev);
-    if (capture_x_events_[xev.type]) {
+    if (capture_x_events_[xev.type]
+#if defined(HAVE_XINPUT2)
+        && (xev.type != GenericEvent || xev.xcookie.extension == xiopcode_)
+#endif
+        ) {
       XNextEvent(display, &xev);
 
       bool processed = static_cast<MessagePumpGlibXDispatcher*>
@@ -48,6 +100,13 @@ bool MessagePumpGlibX::RunOnce(GMainContext* context, bool block) {
 
       if (!processed) {
         DLOG(WARNING) << "Event (" << xev.type << ") not handled.";
+
+        // TODO(sad): It is necessary to put back the event so that the default
+        // GDK events handler can take care of it. Without this, it is
+        // impossible to use the omnibox at the moment. However, this will
+        // eventually be removed once the omnibox code is updated for touchui.
+        XPutBackEvent(display, &xev);
+        g_main_context_iteration(context, FALSE);
       }
     } else {
       // TODO(sad): A couple of extra events can still sneak in during this.
@@ -94,8 +153,90 @@ void MessagePumpGlibX::InitializeEventsToCapture(void) {
 
   capture_x_events_[MotionNotify] = true;
   capture_gdk_events_[GDK_MOTION_NOTIFY] = true;
+
+#if defined(HAVE_XINPUT2)
+  capture_x_events_[GenericEvent] = true;
+#endif
+}
+
+#if defined(HAVE_XINPUT2)
+void MessagePumpGlibX::InitializeXInput2(void) {
+  GdkDisplay* display = gdk_display_get_default();
+  Display* xdisplay = GDK_DISPLAY_XDISPLAY(display);
+  int event, err;
+
+  if (!XQueryExtension(xdisplay, "XInputExtension", &xiopcode_, &event, &err)) {
+    DLOG(WARNING) << "X Input extension not available.";
+    xiopcode_ = -1;
+    return;
+  }
+
+  int major = 2, minor = 0;
+  if (XIQueryVersion(xdisplay, &major, &minor) == BadRequest) {
+    DLOG(WARNING) << "XInput2 not supported in the server.";
+    xiopcode_ = -1;
+    return;
+  }
+
+  SetupGtkWidgetRealizeNotifier(this);
+
+  // Instead of asking X for the list of devices all the time, let's maintain a
+  // list of slave (physical) and master (virtual) pointer devices.
+  int count = 0;
+  XIDeviceInfo* devices = XIQueryDevice(xdisplay, XIAllDevices, &count);
+  for (int i = 0; i < count; i++) {
+    XIDeviceInfo* devinfo = devices + i;
+    if (devinfo->use == XISlavePointer) {
+      slaves_.insert(devinfo->deviceid);
+    } else if (devinfo->use == XIMasterPointer) {
+      masters_.insert(devinfo->deviceid);
+    }
+    // We do not need to care about XIFloatingSlave, because the callback for
+    // XI_HierarchyChanged event will take care of it.
+  }
+  XIFreeDeviceInfo(devices);
+
+  // TODO(sad): Select on root for XI_HierarchyChanged so that slaves_ and
+  // masters_ can be kept up-to-date. This is a relatively rare event, so we can
+  // put it off for a later time.
+  // Note: It is not necessary to listen for XI_DeviceChanged events.
 }
 
+void MessagePumpGlibX::SetupXInput2ForXWindow(Window xwindow) {
+  Display* xdisplay = GDK_DISPLAY_XDISPLAY(gdk_display_get_default());
+
+  // Setup mask for mouse events.
+  unsigned char mask[(XI_LASTEVENT + 7)/8];
+  memset(mask, 0, sizeof(mask));
+
+  XISetMask(mask, XI_ButtonPress);
+  XISetMask(mask, XI_ButtonRelease);
+  XISetMask(mask, XI_Motion);
+
+  // It is necessary to select only for the master devices. XInput2 provides
+  // enough information to the event callback to decide which slave device
+  // triggered the event, thus decide whether the 'pointer event' is a 'mouse
+  // event' or a 'touch event'. So it is not necessary to select for the slave
+  // devices here.
+  XIEventMask evmasks[masters_.size()];
+  int count = 0;
+  for (std::set<int>::const_iterator iter = masters_.begin();
+       iter != masters_.end();
+       ++iter, ++count) {
+    evmasks[count].deviceid = *iter;
+    evmasks[count].mask_len = sizeof(mask);
+    evmasks[count].mask = mask;
+  }
+
+  XISelectEvents(xdisplay, xwindow, evmasks, masters_.size());
+
+  // TODO(sad): Setup masks for keyboard events.
+
+  XFlush(xdisplay);
+}
+
+#endif  // HAVE_XINPUT2
+
 void MessagePumpGlibX::EventDispatcherX(GdkEvent* event, gpointer data) {
   MessagePumpGlibX* pump_x = reinterpret_cast<MessagePumpGlibX*>(data);