Cleaning up a few X scroll bar bits.

* termhooks.h (enum scroll_bar_part): Add scroll_bar_nowhere member.
* xterm.h (struct scroll_bar) [USE_TOOLKIT_SCROLL_BARS && USE_LUCID]:
New member last_seen_part, going to replace...
* xterm.c [USE_TOOLKIT_SCROLL_BARS]: ...global last_scroll_bar_part.
(xt_action_hook) [USE_LUCID]: Adjust user.
(xm_scroll_callback, xg_scroll_callback): Do not bloat with
Lucid-specific scroll bar support.
(xaw_jump_callback, xaw_scroll_callback): Prefer enum scroll_par_part
to int and adjust to use last_seen_part member.
(x_set_toolkit_scroll_bar_thumb) [USE_LUCID]: Adjust user.
(x_scroll_bar_create) [USE_TOOLKIT_SCROLL_BARS && USE_LUCID]:
Initialize last_seen_part.

4 files changed, 37 insertions, 15 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index db08fe6aae8..41e20465d57 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,19 @@
+2013-09-11  Dmitry Antipov  <dmantipov@yandex.ru>
+
+        Cleaning up a few X scroll bar bits.
+        * termhooks.h (enum scroll_bar_part): Add scroll_bar_nowhere member.
+        * xterm.h (struct scroll_bar) [USE_TOOLKIT_SCROLL_BARS && USE_LUCID]:
+        New member last_seen_part, going to replace...
+        * xterm.c [USE_TOOLKIT_SCROLL_BARS]: ...global last_scroll_bar_part.
+        (xt_action_hook) [USE_LUCID]: Adjust user.
+        (xm_scroll_callback, xg_scroll_callback): Do not bloat with
+        Lucid-specific scroll bar support.
+        (xaw_jump_callback, xaw_scroll_callback): Prefer enum scroll_par_part
+        to int and adjust to use last_seen_part member.
+        (x_set_toolkit_scroll_bar_thumb) [USE_LUCID]: Adjust user.
+        (x_scroll_bar_create) [USE_TOOLKIT_SCROLL_BARS && USE_LUCID]:
+        Initialize last_seen_part.
+
 2013-09-11  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * insdel.c (insert_from_buffer_1): Don't mark buffer as modified when
diff --git a/src/termhooks.h b/src/termhooks.h
index 77f98938edb..30ac7957317 100644
--- a/src/termhooks.h
+++ b/src/termhooks.h
@@ -31,6 +31,7 @@ INLINE_HEADER_BEGIN
 #endif
 
 enum scroll_bar_part {
+  scroll_bar_nowhere = -1,
   scroll_bar_above_handle,
   scroll_bar_handle,
   scroll_bar_below_handle,
diff --git a/src/xterm.c b/src/xterm.c
index 22671a5f168..7ad790edd61 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -4081,10 +4081,6 @@ static void x_set_toolkit_scroll_bar_thumb (struct scroll_bar *,
 
 static Lisp_Object window_being_scrolled;
 
-/* Last scroll bar part sent in xm_scroll_callback.  */
-
-static int last_scroll_bar_part;
-
 /* Whether this is an Xaw with arrow-scrollbars.  This should imply
    that movements of 1/20 of the screen size are mapped to up/down.  */
 
@@ -4126,20 +4122,23 @@ xt_action_hook (Widget widget, XtPointer client_data, String action_name,
       && WINDOWP (window_being_scrolled))
     {
       struct window *w;
+      struct scroll_bar *bar;
 
       x_send_scroll_bar_event (window_being_scrolled,
                                scroll_bar_end_scroll, 0, 0);
       w = XWINDOW (window_being_scrolled);
+      bar = XSCROLL_BAR (w->vertical_scroll_bar);
 
-      if (XSCROLL_BAR (w->vertical_scroll_bar)->dragging != -1)
+      if (bar->dragging != -1)
         {
-          XSCROLL_BAR (w->vertical_scroll_bar)->dragging = -1;
+          bar->dragging = -1;
           /* The thumb size is incorrect while dragging: fix it.  */
           set_vertical_scroll_bar (w);
         }
       window_being_scrolled = Qnil;
-      last_scroll_bar_part = -1;
-
+#if defined (USE_LUCID)
+      bar->last_seen_part = scroll_bar_nowhere;
+#endif
       /* Xt timeouts no longer needed.  */
       toolkit_scroll_bar_interaction = 0;
     }
@@ -4323,7 +4322,6 @@ xm_scroll_callback (Widget widget, XtPointer client_data, XtPointer call_data)
   if (part >= 0)
     {
       window_being_scrolled = bar->window;
-      last_scroll_bar_part = part;
       x_send_scroll_bar_event (bar->window, part, portion, whole);
     }
 }
@@ -4384,7 +4382,6 @@ xg_scroll_callback (GtkRange     *range,
   if (part >= 0)
     {
       window_being_scrolled = bar->window;
-      last_scroll_bar_part = part;
       x_send_scroll_bar_event (bar->window, part, portion, whole);
     }
 
@@ -4426,7 +4423,7 @@ xaw_jump_callback (Widget widget, XtPointer client_data, XtPointer call_data)
   float top = *top_addr;
   float shown;
   int whole, portion, height;
-  int part;
+  enum scroll_bar_part part;
 
   /* Get the size of the thumb, a value between 0 and 1.  */
   block_input ();
@@ -4448,7 +4445,7 @@ xaw_jump_callback (Widget widget, XtPointer client_data, XtPointer call_data)
 
   window_being_scrolled = bar->window;
   bar->dragging = portion;
-  last_scroll_bar_part = part;
+  bar->last_seen_part = part;
   x_send_scroll_bar_event (bar->window, part, portion, whole);
 }
 
@@ -4468,7 +4465,7 @@ xaw_scroll_callback (Widget widget, XtPointer client_data, XtPointer call_data)
   /* The position really is stored cast to a pointer.  */
   int position = (intptr_t) call_data;
   Dimension height;
-  int part;
+  enum scroll_bar_part part;
 
   /* Get the height of the scroll bar.  */
   block_input ();
@@ -4487,7 +4484,7 @@ xaw_scroll_callback (Widget widget, XtPointer client_data, XtPointer call_data)
 
   window_being_scrolled = bar->window;
   bar->dragging = -1;
-  last_scroll_bar_part = part;
+  bar->last_seen_part = part;
   x_send_scroll_bar_event (bar->window, part, position, height);
 }
 
@@ -4797,7 +4794,7 @@ x_set_toolkit_scroll_bar_thumb (struct scroll_bar *bar, int portion, int positio
                    NULL);
 
     /* Massage the top+shown values.  */
-    if (bar->dragging == -1 || last_scroll_bar_part == scroll_bar_down_arrow)
+    if (bar->dragging == -1 || bar->last_seen_part == scroll_bar_down_arrow)
       top = max (0, min (1, top));
     else
       top = old_top;
@@ -4902,6 +4899,9 @@ x_scroll_bar_create (struct window *w, int top, int left, int width, int height)
   bar->end = 0;
   bar->dragging = -1;
   bar->fringe_extended_p = 0;
+#if defined (USE_TOOLKIT_SCROLL_BARS) && defined (USE_LUCID)
+  bar->last_seen_part = scroll_bar_nowhere;
+#endif
 
   /* Add bar to its frame's list of scroll bars.  */
   bar->next = FRAME_SCROLL_BARS (f);
diff --git a/src/xterm.h b/src/xterm.h
index 883a249629d..f4a2d4c01b2 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -801,6 +801,11 @@ struct scroll_bar
      being dragged, this is -1.  */
   int dragging;
 
+#if defined (USE_TOOLKIT_SCROLL_BARS) && defined (USE_LUCID)
+  /* Last scroll bar part seen in xaw_jump_callback and xaw_scroll_callback.  */
+  enum scroll_bar_part last_seen_part;
+#endif
+
   /* 1 if the background of the fringe that is adjacent to a scroll
      bar is extended to the gap between the fringe and the bar.  */
   unsigned fringe_extended_p : 1;