[mutter] wayland: Store and retrieve implicit grab information for tablet tools

[Carlos Garnacho <carlosg src gnome org>]

commit ca600973baef6aebde4c0ee16d561ee8b5afdd80
Author: Jason Gerecke <killertofu gmail com>
Date:   Fri Jun 23 08:02:21 2017 -0700

    wayland: Store and retrieve implicit grab information for tablet tools
    
    Window moving and resizing depends on the `meta_wayland_seat_get_grab_info`
    function succeeding. At the moment, tablet tools do not generate implicit
    grabs like the pointer and touch. This commit adds the necessary elements
    to track implicit grabs and retrieve their information.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=777333

 src/wayland/meta-wayland-seat.c        |   56 ++++++++++++++++++++++----------
 src/wayland/meta-wayland-seat.h        |    1 +
 src/wayland/meta-wayland-tablet-tool.c |   42 ++++++++++++++++++++++-
 src/wayland/meta-wayland-tablet-tool.h |    6 +++
 4 files changed, 86 insertions(+), 19 deletions(-)
---
diff --git a/src/wayland/meta-wayland-seat.c b/src/wayland/meta-wayland-seat.c
index 6858dcb..a574594 100644
--- a/src/wayland/meta-wayland-seat.c
+++ b/src/wayland/meta-wayland-seat.c
@@ -426,36 +426,58 @@ meta_wayland_seat_get_grab_info (MetaWaylandSeat    *seat,
                                  gfloat             *x,
                                  gfloat             *y)
 {
-  ClutterEventSequence *sequence = NULL;
-  gboolean can_grab_surface = FALSE;
+  MetaWaylandCompositor *compositor;
+  MetaWaylandTabletSeat *tablet_seat;
+  GList *tools, *l;
 
-  if (meta_wayland_seat_has_touch (seat))
-    sequence = meta_wayland_touch_find_grab_sequence (seat->touch,
-                                                      surface,
-                                                      serial);
+  compositor = meta_wayland_compositor_get_default ();
+  tablet_seat = meta_wayland_tablet_manager_ensure_seat (compositor->tablet_manager, seat);
+  tools = g_hash_table_get_values (tablet_seat->tools);
 
-  if (sequence)
+  if (meta_wayland_seat_has_touch (seat))
     {
-      meta_wayland_touch_get_press_coords (seat->touch, sequence, x, y);
+      ClutterEventSequence *sequence;
+      sequence = meta_wayland_touch_find_grab_sequence (seat->touch,
+                                                        surface,
+                                                        serial);
+      if (sequence)
+        {
+          meta_wayland_touch_get_press_coords (seat->touch, sequence, x, y);
+          return TRUE;
+        }
     }
-  else
-    {
-      if (meta_wayland_seat_has_pointer (seat) &&
-          (!require_pressed || seat->pointer->button_count > 0))
-        can_grab_surface = meta_wayland_pointer_can_grab_surface (seat->pointer,
-                                                                  surface,
-                                                                  serial);
 
-      if (can_grab_surface)
+  if (meta_wayland_seat_has_pointer (seat))
+    {
+      if ((!require_pressed || seat->pointer->button_count > 0) &&
+          meta_wayland_pointer_can_grab_surface (seat->pointer, surface, serial))
         {
           if (x)
             *x = seat->pointer->grab_x;
           if (y)
             *y = seat->pointer->grab_y;
+
+          return TRUE;
         }
     }
 
-  return sequence || can_grab_surface;
+  for (l = tools; l; l = l->next)
+    {
+      MetaWaylandTabletTool *tool = l->data;
+
+      if ((!require_pressed || tool->button_count > 0) &&
+          meta_wayland_tablet_tool_can_grab_surface (tool, surface, serial))
+        {
+          if (x)
+            *x = tool->grab_x;
+          if (y)
+            *y = tool->grab_y;
+
+          return TRUE;
+        }
+    }
+
+  return FALSE;
 }
 
 gboolean
diff --git a/src/wayland/meta-wayland-seat.h b/src/wayland/meta-wayland-seat.h
index 52db072..78abb15 100644
--- a/src/wayland/meta-wayland-seat.h
+++ b/src/wayland/meta-wayland-seat.h
@@ -31,6 +31,7 @@
 #include "meta-wayland-keyboard.h"
 #include "meta-wayland-touch.h"
 #include "meta-wayland-data-device.h"
+#include "meta-wayland-tablet-tool.h"
 
 struct _MetaWaylandSeat
 {
diff --git a/src/wayland/meta-wayland-tablet-tool.c b/src/wayland/meta-wayland-tablet-tool.c
index 6c19352..cd55f20 100644
--- a/src/wayland/meta-wayland-tablet-tool.c
+++ b/src/wayland/meta-wayland-tablet-tool.c
@@ -572,9 +572,15 @@ meta_wayland_tablet_tool_account_button (MetaWaylandTabletTool *tool,
                                          const ClutterEvent    *event)
 {
   if (event->type == CLUTTER_BUTTON_PRESS)
-    tool->pressed_buttons |= 1 << (event->button.button - 1);
+    {
+      tool->pressed_buttons |= 1 << (event->button.button - 1);
+      tool->button_count++;
+    }
   else if (event->type == CLUTTER_BUTTON_RELEASE)
-    tool->pressed_buttons &= ~(1 << (event->button.button - 1));
+    {
+      tool->pressed_buttons &= ~(1 << (event->button.button - 1));
+      tool->button_count--;
+    }
 }
 
 static void
@@ -840,6 +846,9 @@ handle_button_event (MetaWaylandTabletTool *tool,
   if (!tool->focus_surface)
     return;
 
+  if (event->type == CLUTTER_BUTTON_PRESS && tool->button_count == 1)
+    clutter_event_get_coords (event, &tool->grab_x, &tool->grab_y);
+
   if (event->type == CLUTTER_BUTTON_PRESS && event->button.button == 1)
     broadcast_down (tool, event);
   else if (event->type == CLUTTER_BUTTON_RELEASE && event->button.button == 1)
@@ -918,3 +927,32 @@ meta_wayland_tablet_tool_set_cursor_position (MetaWaylandTabletTool *tool,
   if (tool->cursor_renderer)
     meta_cursor_renderer_set_position (tool->cursor_renderer, new_x, new_y);
 }
+
+static gboolean
+tablet_tool_can_grab_surface (MetaWaylandTabletTool *tool,
+                              MetaWaylandSurface    *surface)
+{
+  GList *l;
+
+  if (tool->focus_surface == surface)
+    return TRUE;
+
+  for (l = surface->subsurfaces; l; l = l->next)
+    {
+      MetaWaylandSurface *subsurface = l->data;
+
+      if (tablet_tool_can_grab_surface (tool, subsurface))
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
+gboolean
+meta_wayland_tablet_tool_can_grab_surface (MetaWaylandTabletTool *tool,
+                                           MetaWaylandSurface    *surface,
+                                           uint32_t               serial)
+{
+  return ((tool->down_serial == serial || tool->button_serial == serial) &&
+          tablet_tool_can_grab_surface (tool, surface));
+}
diff --git a/src/wayland/meta-wayland-tablet-tool.h b/src/wayland/meta-wayland-tablet-tool.h
index b7cfce0..351abbc 100644
--- a/src/wayland/meta-wayland-tablet-tool.h
+++ b/src/wayland/meta-wayland-tablet-tool.h
@@ -48,11 +48,14 @@ struct _MetaWaylandTabletTool
 
   MetaWaylandSurface *current;
   guint32 pressed_buttons;
+  guint32 button_count;
 
   guint32 proximity_serial;
   guint32 down_serial;
   guint32 button_serial;
 
+  float grab_x, grab_y;
+
   MetaWaylandTablet *current_tablet;
 };
 
@@ -79,5 +82,8 @@ void     meta_wayland_tablet_tool_set_cursor_position (MetaWaylandTabletTool  *t
                                                        int                     new_x,
                                                        int                     new_y);
 
+gboolean meta_wayland_tablet_tool_can_grab_surface (MetaWaylandTabletTool *tool,
+                                                    MetaWaylandSurface    *surface,
+                                                    uint32_t               serial);
 
 #endif /* META_WAYLAND_TABLET_TOOL_H */