master f39d25d5fe: Fix handling of XI_DeviceChanged events

[Po Lu]

branch: master
commit f39d25d5fe2577493ec5718d11b57d1511de4f7f
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Fix handling of XI_DeviceChanged events
    
    * src/xterm.c (xi_get_scroll_valuator): New function.
    (xi_handle_device_changed): New function.
    (handle_one_xevent): Factor out most of the device changed code
    to that function, and make it specifically query for the device
    information.  (bug#57020)
---
 src/xterm.c | 257 +++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 150 insertions(+), 107 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 36797bc0ab..7b90f8b481 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -12705,6 +12705,151 @@ xi_handle_interaction (struct x_display_info *dpyinfo,
     xi_handle_focus_change (dpyinfo);
 }
 
+#ifdef HAVE_XINPUT2_1
+
+/* Look up a scroll valuator in DEVICE by NUMBER.  */
+
+static struct xi_scroll_valuator_t *
+xi_get_scroll_valuator (struct xi_device_t *device, int number)
+{
+  int i;
+
+  for (i = 0; i < device->scroll_valuator_count; ++i)
+    {
+      if (device->valuators[i].number == number)
+       return &device->valuators[i];
+    }
+
+  return NULL;
+}
+
+#endif
+
+/* Handle EVENT, a DeviceChanged event.  Look up the device that
+   changed, and update its information with the data in EVENT.  */
+
+static void
+xi_handle_device_changed (struct x_display_info *dpyinfo,
+                         struct xi_device_t *device,
+                         XIDeviceChangedEvent *event)
+{
+#ifdef HAVE_XINPUT2_1
+  XIDeviceInfo *info;
+  XIScrollClassInfo *scroll;
+  int i, ndevices;
+  struct xi_scroll_valuator_t *valuator;
+  XIValuatorClassInfo *valuator_info;
+#endif
+#ifdef HAVE_XINPUT2_2
+  struct xi_touch_point_t *tem, *last;
+  XITouchClassInfo *touch;
+#endif
+
+#ifdef HAVE_XINPUT2_1
+  /* When a DeviceChange event is received for a master device, we
+     don't get any scroll valuators along with it.  This is possibly
+     an X server bug but I really don't want to dig any further, so
+     fetch the scroll valuators manually.  (bug#57020) */
+
+  x_catch_errors (dpyinfo->display);
+  info = XIQueryDevice (dpyinfo->display, event->deviceid,
+                       /* ndevices is always 1 if a deviceid is
+                          specified.  If the request fails, NULL will
+                          be returned.  */
+                       &ndevices);
+  x_uncatch_errors ();
+
+  if (info)
+    {
+      device->valuators = xrealloc (device->valuators,
+                                   (info->num_classes
+                                    * sizeof *device->valuators));
+      device->scroll_valuator_count = 0;
+#ifdef HAVE_XINPUT2_2
+      device->direct_p = false;
+#endif
+
+      for (i = 0; i < info->num_classes; ++i)
+       {
+         switch (info->classes[i]->type)
+           {
+           case XIScrollClass:
+             scroll = (XIScrollClassInfo *) info->classes[i];
+
+             valuator = &device->valuators[device->scroll_valuator_count++];
+             valuator->horizontal = (scroll->scroll_type
+                                     == XIScrollTypeHorizontal);
+             valuator->invalid_p = true;
+             valuator->emacs_value = DBL_MIN;
+             valuator->increment = scroll->increment;
+             valuator->number = scroll->number;
+             break;
+
+#ifdef HAVE_XINPUT2_2
+           case XITouchClass:
+             touch = (XITouchClassInfo *) info->classes[i];
+
+             if (touch->mode == XIDirectTouch)
+               device->direct_p = true;
+             break;
+#endif
+           }
+       }
+
+      /* Restore the values of any scroll valuators that we already
+        know about.  */
+
+      for (i = 0; i < info->num_classes; ++i)
+       {
+         switch (info->classes[i]->type)
+           {
+           case XIValuatorClass:
+             valuator_info = (XIValuatorClassInfo *) info->classes[i];
+
+             valuator = xi_get_scroll_valuator (device,
+                                                valuator_info->number);
+             if (valuator)
+               {
+                 valuator->invalid_p = false;
+                 valuator->current_value = valuator_info->value;
+
+                 /* Make sure that this is reset if the pointer moves
+                    into a window of ours.
+
+                    Otherwise the valuator state could be left
+                    invalid if the DeviceChange event happened with
+                    the pointer outside any Emacs frame. */
+                 valuator->pending_enter_reset = true;
+               }
+
+             break;
+           }
+       }
+
+#ifdef HAVE_XINPUT2_2
+      /* The device is no longer a DirectTouch device, so
+        remove any touchpoints that we might have
+        recorded.  */
+      if (!device->direct_p)
+       {
+         tem = device->touchpoints;
+
+         while (tem)
+           {
+             last = tem;
+             tem = tem->next;
+             xfree (last);
+           }
+
+         device->touchpoints = NULL;
+       }
+#endif
+
+      XIFreeDeviceInfo (info);
+    }
+#endif
+}
+
 #endif
 
 /* The focus may have changed.  Figure out if it is a real focus change,
@@ -22363,16 +22508,10 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 
          case XI_DeviceChanged:
            {
-             XIDeviceChangedEvent *device_changed = (XIDeviceChangedEvent *) 
xi_event;
+             XIDeviceChangedEvent *device_changed;
              struct xi_device_t *device;
-#ifdef HAVE_XINPUT2_2
-             struct xi_touch_point_t *tem, *last;
-#endif
-             int c;
-#ifdef HAVE_XINPUT2_1
-             int i;
-#endif
 
+             device_changed = (XIDeviceChangedEvent *) xi_event;
              device = xi_device_from_id (dpyinfo, device_changed->deviceid);
 
              /* If the device isn't enabled, then stop handling this
@@ -22381,105 +22520,9 @@ handle_one_xevent (struct x_display_info *dpyinfo,
              if (!device)
                goto XI_OTHER;
 
-             /* Free data that we will regenerate from new
-                information.  */
-#ifdef HAVE_XINPUT2_1
-             device->valuators = xrealloc (device->valuators,
-                                           (device_changed->num_classes
-                                            * sizeof *device->valuators));
-             device->scroll_valuator_count = 0;
-#endif
-#ifdef HAVE_XINPUT2_2
-             device->direct_p = false;
-#endif
-
-             for (c = 0; c < device_changed->num_classes; ++c)
-               {
-                 switch (device_changed->classes[c]->type)
-                   {
-#ifdef HAVE_XINPUT2_1
-                   case XIScrollClass:
-                     {
-                       XIScrollClassInfo *info;
-
-                       info = (XIScrollClassInfo *) device_changed->classes[c];
-                       struct xi_scroll_valuator_t *valuator;
-
-                       valuator = 
&device->valuators[device->scroll_valuator_count++];
-                       valuator->horizontal
-                         = (info->scroll_type == XIScrollTypeHorizontal);
-                       valuator->invalid_p = true;
-                       valuator->emacs_value = DBL_MIN;
-                       valuator->increment = info->increment;
-                       valuator->number = info->number;
-
-                       break;
-                     }
-#endif
-
-#ifdef HAVE_XINPUT2_2
-                   case XITouchClass:
-                     {
-                       XITouchClassInfo *info;
-
-                       info = (XITouchClassInfo *) device_changed->classes[c];
-                       device->direct_p = info->mode == XIDirectTouch;
-                     }
-#endif
-                   default:
-                     break;
-                   }
-               }
-
-#ifdef HAVE_XINPUT2_1
-             for (c = 0; c < device_changed->num_classes; ++c)
-               {
-                 if (device_changed->classes[c]->type == XIValuatorClass)
-                   {
-                     XIValuatorClassInfo *info;
-
-                     info = (XIValuatorClassInfo *) device_changed->classes[c];
-
-                     for (i = 0; i < device->scroll_valuator_count; ++i)
-                       {
-                         if (device->valuators[i].number == info->number)
-                           {
-                             device->valuators[i].invalid_p = false;
-                             device->valuators[i].current_value = info->value;
-
-                             /* Make sure that this is reset if the
-                                pointer moves into a window of ours.
-
-                                Otherwise the valuator state could be
-                                left invalid if the DeviceChange
-                                event happened with the pointer
-                                outside any Emacs frame. */
-                             device->valuators[i].pending_enter_reset = true;
-                           }
-                       }
-                   }
-               }
-#endif
-
-#ifdef HAVE_XINPUT2_2
-             /* The device is no longer a DirectTouch device, so
-                remove any touchpoints that we might have
-                recorded.  */
-             if (!device->direct_p)
-               {
-                 tem = device->touchpoints;
-
-                 while (tem)
-                   {
-                     last = tem;
-                     tem = tem->next;
-                     xfree (last);
-                   }
-
-                 device->touchpoints = NULL;
-               }
-#endif
-
+             /* Now handle the event by retrieving scroll valuators
+                and touch info.  */
+             xi_handle_device_changed (dpyinfo, device, device_changed);
              goto XI_OTHER;
            }