Tweak XInput2 event subscription

base/message_pump_glib_x.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/message_pump_glib_x.h"
 
 #include <gdk/gdkx.h>
 #if defined(HAVE_XINPUT2)
 #include <X11/extensions/XInput2.h>
 #else
@@ skipping 61 matching lines @@
 
 #endif  // HAVE_XINPUT2
 
 }  // namespace
 
 namespace base {
 
 MessagePumpGlibX::MessagePumpGlibX() : base::MessagePumpForUI(),
 #if defined(HAVE_XINPUT2)
     xiopcode_(-1),
-    masters_(),
-    floats_(),
+    pointer_devices_(),
 #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
@@ skipping 11 matching lines @@
   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 not necessary to select for slave 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'.
-  // If the touch device has 'GrabDevice' set and 'SendCoreEvents' unset (which
-  // is possible), then the device is detected as a floating device, and a
-  // floating device is not connected to a master device. So it is necessary to
-  // also select on the floating devices.
-  std::set<int> devices;
-  std::set_union(masters_.begin(), masters_.end(),
-                 floats_.begin(), floats_.end(),
-                 std::inserter(devices, devices.begin()));
-  XIEventMask evmasks[devices.size()];
+  XIEventMask evmasks[pointer_devices_.size()];
   int count = 0;
-  for (std::set<int>::const_iterator iter = devices.begin();
-       iter != devices.end();
+  for (std::set<int>::const_iterator iter = pointer_devices_.begin();
+       iter != pointer_devices_.end();
        ++iter, ++count) {
     evmasks[count].deviceid = *iter;
     evmasks[count].mask_len = sizeof(mask);
     evmasks[count].mask = mask;
   }
 
-  XISelectEvents(xdisplay, xwindow, evmasks, devices.size());
+  XISelectEvents(xdisplay, xwindow, evmasks, pointer_devices_.size());
 
   // TODO(sad): Setup masks for keyboard events.
 
   XFlush(xdisplay);
 }
 #endif  // HAVE_XINPUT2
 
 bool MessagePumpGlibX::RunOnce(GMainContext* context, bool block) {
   GdkDisplay* gdisp = gdk_display_get_default();
   if (!gdisp || !GetDispatcher())
@@ skipping 142 matching lines @@
     xiopcode_ = -1;
     return;
   }
 
   // TODO(sad): Here, we only setup so that the X windows created by GTK+ are
   // setup for XInput2 events. We need a way to listen for XInput2 events for X
   // windows created by other means (e.g. for context menus).
   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.
+  // list of pointer devices we care about.
+  // It is not necessary to select for slave 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'.
+  // If the touch device has 'GrabDevice' set and 'SendCoreEvents' unset (which
+  // is possible), then the device is detected as a floating device, and a
+  // floating device is not connected to a master device. So it is necessary to
+  // also select on the floating devices.
   int count = 0;
   XIDeviceInfo* devices = XIQueryDevice(xdisplay, XIAllDevices, &count);
   for (int i = 0; i < count; i++) {
     XIDeviceInfo* devinfo = devices + i;
-    if (devinfo->use == XIFloatingSlave) {
-      floats_.insert(devinfo->deviceid);
-    } else if (devinfo->use == XIMasterPointer) {
-      masters_.insert(devinfo->deviceid);
-    }
+    if (devinfo->use == XIFloatingSlave || devinfo->use == XIMasterPointer)
+      pointer_devices_.insert(devinfo->deviceid);
   }
   XIFreeDeviceInfo(devices);
 
   // TODO(sad): Select on root for XI_HierarchyChanged so that floats_ 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.
 }
 #endif  // HAVE_XINPUT2
 
 }  // namespace base