[gtk+/gtk-3-14] Revert "x11: Query pointer devices' scroll valuators on toplevel enter events"

[Matthias Clasen <matthiasc src gnome org>]

commit ee7083931f54bade741546adf212036028a59936
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 15 16:31:42 2015 -0400

    Revert "x11: Query pointer devices' scroll valuators on toplevel enter events"
    
    This reverts commit 33e6b73145de3107c572b89ffc1b7c9374016dd5.
    
    This commit broke more scenarios than it fixes, not suitable for stable branches.

 gdk/x11/gdkdevice-xi2.c        |   39 ++++++++++++++++-----------------------
 gdk/x11/gdkdevicemanager-xi2.c |   15 ++++++++++-----
 gdk/x11/gdkprivate-x11.h       |    2 --
 3 files changed, 26 insertions(+), 30 deletions(-)
---
diff --git a/gdk/x11/gdkdevice-xi2.c b/gdk/x11/gdkdevice-xi2.c
index 08cffae..bc60428 100644
--- a/gdk/x11/gdkdevice-xi2.c
+++ b/gdk/x11/gdkdevice-xi2.c
@@ -40,6 +40,7 @@ struct _ScrollValuator
 {
   guint n_valuator       : 4;
   guint direction        : 4;
+  guint last_value_valid : 1;
   gdouble last_value;
   gdouble increment;
 };
@@ -824,8 +825,8 @@ _gdk_x11_device_xi2_add_scroll_valuator (GdkX11DeviceXI2    *device,
 
   scroll.n_valuator = n_valuator;
   scroll.direction = direction;
+  scroll.last_value_valid = FALSE;
   scroll.increment = increment;
-  scroll.last_value = 0;
 
   g_array_append_val (device->scroll_valuators, scroll);
 }
@@ -856,10 +857,18 @@ _gdk_x11_device_xi2_get_scroll_delta (GdkX11DeviceXI2    *device,
           if (delta_ret)
             *delta_ret = 0;
 
-          if (delta_ret)
-            *delta_ret = (valuator_value - scroll->last_value) / scroll->increment;
+          if (scroll->last_value_valid)
+            {
+              if (delta_ret)
+                *delta_ret = (valuator_value - scroll->last_value) / scroll->increment;
 
-          scroll->last_value = valuator_value;
+              scroll->last_value = valuator_value;
+            }
+          else
+            {
+              scroll->last_value = valuator_value;
+              scroll->last_value_valid = TRUE;
+            }
 
           return TRUE;
         }
@@ -869,33 +878,17 @@ _gdk_x11_device_xi2_get_scroll_delta (GdkX11DeviceXI2    *device,
 }
 
 void
-_gdk_device_xi2_revalidate_scroll_valuators (GdkX11DeviceXI2 *device)
+_gdk_device_xi2_reset_scroll_valuators (GdkX11DeviceXI2 *device)
 {
-  GdkDisplay *display;
-  XIDeviceInfo *info;
-  gint i, ndevices;
-
-  display = gdk_device_get_display (GDK_DEVICE (device));
-
-  gdk_x11_display_error_trap_push (display);
-  info = XIQueryDevice (GDK_DISPLAY_XDISPLAY (display),
-                        device->device_id, &ndevices);
-  gdk_x11_display_error_trap_pop_ignored (display);
-
-  if (!info)
-    return;
+  guint i;
 
   for (i = 0; i < device->scroll_valuators->len; i++)
     {
-      XIValuatorClassInfo *valuator;
       ScrollValuator *scroll;
 
       scroll = &g_array_index (device->scroll_valuators, ScrollValuator, i);
-      valuator = (XIValuatorClassInfo *) info->classes[scroll->n_valuator + 1];
-      scroll->last_value = valuator->value;
+      scroll->last_value_valid = FALSE;
     }
-
-  XIFreeDeviceInfo (info);
 }
 
 void
diff --git a/gdk/x11/gdkdevicemanager-xi2.c b/gdk/x11/gdkdevicemanager-xi2.c
index 08e74fb..0ce2e1c 100644
--- a/gdk/x11/gdkdevicemanager-xi2.c
+++ b/gdk/x11/gdkdevicemanager-xi2.c
@@ -754,11 +754,13 @@ handle_device_changed (GdkX11DeviceManagerXI2 *device_manager,
                        XIDeviceChangedEvent   *ev)
 {
   GdkDisplay *display;
-  GdkDevice *device;
+  GdkDevice *device, *source_device;
 
   display = gdk_device_manager_get_display (GDK_DEVICE_MANAGER (device_manager));
   device = g_hash_table_lookup (device_manager->id_table,
                                 GUINT_TO_POINTER (ev->deviceid));
+  source_device = g_hash_table_lookup (device_manager->id_table,
+                                       GUINT_TO_POINTER (ev->sourceid));
 
   if (device)
     {
@@ -769,6 +771,9 @@ handle_device_changed (GdkX11DeviceManagerXI2 *device_manager,
 
       g_signal_emit_by_name (G_OBJECT (device), "changed");
     }
+
+  if (source_device)
+    _gdk_device_xi2_reset_scroll_valuators (GDK_X11_DEVICE_XI2 (source_device));
 }
 
 static GdkCrossingMode
@@ -1610,16 +1615,16 @@ gdk_x11_device_manager_xi2_translate_event (GdkEventTranslator *translator,
             xev->detail != XINotifyInferior && xev->mode != XINotifyPassiveUngrab &&
            gdk_window_get_window_type (window) == GDK_WINDOW_TOPLEVEL)
           {
-            if (gdk_device_get_device_type (device) != GDK_DEVICE_TYPE_MASTER)
-              _gdk_device_xi2_revalidate_scroll_valuators (GDK_X11_DEVICE_XI2 (source_device));
+            if (gdk_device_get_device_type (source_device) != GDK_DEVICE_TYPE_MASTER)
+              _gdk_device_xi2_reset_scroll_valuators (GDK_X11_DEVICE_XI2 (source_device));
             else
               {
                 GList *slaves, *l;
 
-                slaves = gdk_device_list_slave_devices (device);
+                slaves = gdk_device_list_slave_devices (source_device);
 
                 for (l = slaves; l; l = l->next)
-                  _gdk_device_xi2_revalidate_scroll_valuators (l->data);
+                  _gdk_device_xi2_reset_scroll_valuators (GDK_X11_DEVICE_XI2 (l->data));
 
                 g_list_free (slaves);
               }
diff --git a/gdk/x11/gdkprivate-x11.h b/gdk/x11/gdkprivate-x11.h
index 459b76e..c2afecf 100644
--- a/gdk/x11/gdkprivate-x11.h
+++ b/gdk/x11/gdkprivate-x11.h
@@ -246,8 +246,6 @@ gboolean  _gdk_x11_device_xi2_get_scroll_delta    (GdkX11DeviceXI2    *device,
                                                    GdkScrollDirection *direction_ret,
                                                    gdouble            *delta_ret);
 void     _gdk_device_xi2_reset_scroll_valuators   (GdkX11DeviceXI2    *device);
-void     _gdk_device_xi2_revalidate_scroll_valuators (GdkX11DeviceXI2 *device);
-
 
 gdouble  gdk_x11_device_xi2_get_last_axis_value (GdkX11DeviceXI2 *device,
                                                  gint             n_axis);