* termhooks.h (enum scroll_bar_part): Begin from 0 to allow...

(struct input_event): ...unsigned bitfields.  Likewise for
`event_kind' member.  Prefer unsigned for `code' and 'modifiers'.
Use `timestamp' for HELP_EVENT position.  Add compile-time assert.
* keyboard.c (gen_help_event, kbd_buffer_store_help_event)
(kbd_buffer_get_event): Adjust users.
(scroll_bar_parts): Add Qnil to match scroll_bar_nowhere.
(make_scroll_bar_position): New function, refactored out of...
(make_lispy_event): ...adjusted user.
* nsterm.h (EmacsScroller): Use enum for `last_hit_part' member.
* nsterm.m (ns_mouse_position, mouseUp):
* term.c (term_mouse_position):
* w32inevt.c (w32_console_mouse_position):
* w32term.c (w32_mouse_position):
* xterm.c (XTmouse_position): Use scroll_bar_above_handle.
(x_send_scroll_bar_event, xm_scroll_callback, xg_scroll_callback):
Prefer enum and explicit enum members to integers and numeric values.

9 files changed, 81 insertions, 60 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 0fc4c2b1599..8f312a3ab3e 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,23 @@
+2014-09-24  Dmitry Antipov  <dmantipov@yandex.ru>
+
+        * termhooks.h (enum scroll_bar_part): Begin from 0 to allow...
+        (struct input_event): ...unsigned bitfields.  Likewise for
+        `event_kind' member.  Prefer unsigned for `code' and 'modifiers'.
+        Use `timestamp' for HELP_EVENT position.  Add compile-time assert.
+        * keyboard.c (gen_help_event, kbd_buffer_store_help_event)
+        (kbd_buffer_get_event): Adjust users.
+        (scroll_bar_parts): Add Qnil to match scroll_bar_nowhere.
+        (make_scroll_bar_position): New function, refactored out of...
+        (make_lispy_event): ...adjusted user.
+        * nsterm.h (EmacsScroller): Use enum for `last_hit_part' member.
+        * nsterm.m (ns_mouse_position, mouseUp):
+        * term.c (term_mouse_position):
+        * w32inevt.c (w32_console_mouse_position):
+        * w32term.c (w32_mouse_position):
+        * xterm.c (XTmouse_position): Use scroll_bar_above_handle.
+        (x_send_scroll_bar_event, xm_scroll_callback, xg_scroll_callback):
+        Prefer enum and explicit enum members to integers and numeric values.
+
 2014-09-24  Paul Eggert  <eggert@cs.ucla.edu>
 
         Fix some slow uses and misuses of strcat.
diff --git a/src/keyboard.c b/src/keyboard.c
index f79c1c94167..7625586650f 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -3747,14 +3747,12 @@ gen_help_event (Lisp_Object help, Lisp_Object frame, Lisp_Object window,
 {
   struct input_event event;
 
-  EVENT_INIT (event);
-
   event.kind = HELP_EVENT;
   event.frame_or_window = frame;
   event.arg = object;
   event.x = WINDOWP (window) ? window : frame;
   event.y = help;
-  event.code = pos;
+  event.timestamp = pos;
   kbd_buffer_store_event (&event);
 }
 
@@ -3771,7 +3769,7 @@ kbd_buffer_store_help_event (Lisp_Object frame, Lisp_Object help)
   event.arg = Qnil;
   event.x = Qnil;
   event.y = help;
-  event.code = 0;
+  event.timestamp = 0;
   kbd_buffer_store_event (&event);
 }
 
@@ -4086,7 +4084,7 @@ kbd_buffer_get_event (KBOARD **kbp,
 
           frame = event->frame_or_window;
           object = event->arg;
-          position = make_number (event->code);
+          position = make_number (event->timestamp);
           window = event->x;
           help = event->y;
           clear_event (event);
@@ -5201,9 +5199,11 @@ static Lisp_Object Qleftmost, Qrightmost;
 static Lisp_Object Qend_scroll;
 static Lisp_Object Qratio;
 
-/* An array of scroll bar parts, indexed by an enum scroll_bar_part value.  */
+/* An array of scroll bar parts, indexed by an enum scroll_bar_part value.
+   Note that Qnil corresponds to scroll_bar_nowhere and should not appear
+   in Lisp events.  */
 static Lisp_Object *const scroll_bar_parts[] = {
-  &Qabove_handle, &Qhandle, &Qbelow_handle,
+  &Qnil, &Qabove_handle, &Qhandle, &Qbelow_handle,
   &Qup, &Qdown, &Qtop, &Qbottom, &Qend_scroll, &Qratio,
   &Qbefore_handle, &Qhorizontal_handle, &Qafter_handle,
   &Qleft, &Qright, &Qleftmost, &Qrightmost, &Qend_scroll, &Qratio
@@ -5450,6 +5450,16 @@ toolkit_menubar_in_use (struct frame *f)
 #endif
 }
 
+/* Build the part of Lisp event which represents scroll bar state from
+   EV.  TYPE is one of Qvertical_scroll_bar or Qhorizontal_scroll_bar.  */
+
+static Lisp_Object
+make_scroll_bar_position (struct input_event *ev, Lisp_Object type)
+{
+  return list5 (ev->frame_or_window, type, Fcons (ev->x, ev->y),
+                make_number (ev->timestamp), *scroll_bar_parts[ev->part]);
+}
+
 /* Given a struct input_event, build the lisp event which represents
    it.  If EVENT is 0, build a mouse movement event from the mouse
    movement buffer, which should have a movement event in it.
@@ -5667,20 +5677,8 @@ make_lispy_event (struct input_event *event)
           }
 #ifndef USE_TOOLKIT_SCROLL_BARS
         else
-          {
-            /* It's a scrollbar click.  */
-            Lisp_Object window;
-            Lisp_Object portion_whole;
-            Lisp_Object part;
-
-            window = event->frame_or_window;
-            portion_whole = Fcons (event->x, event->y);
-            part = *scroll_bar_parts[(int) event->part];
-
-            position = list5 (window, Qvertical_scroll_bar,
-                              portion_whole, make_number (event->timestamp),
-                              part);
-          }
+          /* It's a scrollbar click.  */
+          position = make_scroll_bar_position (event, Qvertical_scroll_bar);
 #endif /* not USE_TOOLKIT_SCROLL_BARS */
 
         if (button >= ASIZE (button_down_location))
@@ -5957,14 +5955,9 @@ make_lispy_event (struct input_event *event)
 
     case SCROLL_BAR_CLICK_EVENT:
       {
-        Lisp_Object position, head, window, portion_whole, part;
+        Lisp_Object position, head;
 
-        window = event->frame_or_window;
-        portion_whole = Fcons (event->x, event->y);
-        part = *scroll_bar_parts[(int) event->part];
-
-        position = list5 (window, Qvertical_scroll_bar, portion_whole,
-                          make_number (event->timestamp), part);
+        position = make_scroll_bar_position (event, Qvertical_scroll_bar);
 
         /* Always treat scroll bar events as clicks.  */
         event->modifiers |= click_modifier;
@@ -5987,14 +5980,9 @@ make_lispy_event (struct input_event *event)
 
     case HORIZONTAL_SCROLL_BAR_CLICK_EVENT:
       {
-        Lisp_Object position, head, window, portion_whole, part;
-
-        window = event->frame_or_window;
-        portion_whole = Fcons (event->x, event->y);
-        part = *scroll_bar_parts[(int) event->part];
+        Lisp_Object position, head;
 
-        position = list5 (window, Qhorizontal_scroll_bar, portion_whole,
-                          make_number (event->timestamp), part);
+        position = make_scroll_bar_position (event, Qhorizontal_scroll_bar);
 
         /* Always treat scroll bar events as clicks.  */
         event->modifiers |= click_modifier;
diff --git a/src/nsterm.h b/src/nsterm.h
index 00a0b54add9..e223281de28 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -401,7 +401,7 @@ typedef float EmacsCGFloat;
    CGFloat last_mouse_offset;
    float min_portion;
    int pixel_height;
-   int last_hit_part;
+   enum scroll_bar_part last_hit_part;
 
    BOOL condemned;
 
diff --git a/src/nsterm.m b/src/nsterm.m
index 5f86369a8c4..d40541f5125 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1930,10 +1930,9 @@ ns_mouse_position (struct frame **fp, int insist, Lisp_Object *bar_window,
           position = [view convertPoint: position fromView: nil];
           remember_mouse_glyph (f, position.x, position.y,
                                 &dpyinfo->last_mouse_glyph);
-/*fprintf (stderr, "ns_mouse_position: %.0f, %.0f\n", position.x, position.y); */
 
           if (bar_window) *bar_window = Qnil;
-          if (part) *part = 0; /*scroll_bar_handle; */
+          if (part) *part = scroll_bar_above_handle;
 
           if (x) XSETINT (*x, lrint (position.x));
           if (y) XSETINT (*y, lrint (position.y));
@@ -7505,7 +7504,7 @@ if (cols > 0 && rows > 0)
       [scroll_repeat_entry release];
       scroll_repeat_entry = nil;
     }
-  last_hit_part = 0;
+  last_hit_part = scroll_bar_above_handle;
 }
 
 
diff --git a/src/term.c b/src/term.c
index 0a1b3dd13e2..572435bdd1a 100644
--- a/src/term.c
+++ b/src/term.c
@@ -2540,7 +2540,7 @@ term_mouse_position (struct frame **fp, int insist, Lisp_Object *bar_window,
   (*fp)->mouse_moved = 0;
 
   *bar_window = Qnil;
-  *part = 0;
+  *part = scroll_bar_above_handle;
 
   XSETINT (*x, last_mouse_x);
   XSETINT (*y, last_mouse_y);
diff --git a/src/termhooks.h b/src/termhooks.h
index 04104eb41e9..6412f0da6ca 100644
--- a/src/termhooks.h
+++ b/src/termhooks.h
@@ -28,7 +28,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 INLINE_HEADER_BEGIN
 
 enum scroll_bar_part {
-  scroll_bar_nowhere = -1,
+  scroll_bar_nowhere,
   scroll_bar_above_handle,
   scroll_bar_handle,
   scroll_bar_below_handle,
@@ -255,31 +255,42 @@ enum event_kind
 struct input_event
 {
   /* What kind of event was this?  */
-  enum event_kind kind;
+  ENUM_BF (event_kind) kind : 16;
+
+  /* Used in scroll back click events.  */
+  ENUM_BF (scroll_bar_part) part : 16;
 
   /* For an ASCII_KEYSTROKE_EVENT and MULTIBYTE_CHAR_KEYSTROKE_EVENT,
      this is the character.
      For a NON_ASCII_KEYSTROKE_EVENT, this is the keysym code.
-     For a mouse event, this is the button number.
-     For a HELP_EVENT, this is the position within the object
-      (stored in ARG below) where the help was found.  */
-  ptrdiff_t code;
-  enum scroll_bar_part part;
+     For a mouse event, this is the button number.  */
+  unsigned code;
 
-  int modifiers;                /* See enum below for interpretation.  */
+  /* See enum below for interpretation.  */
+  unsigned modifiers;
 
+  /* One would prefer C integers, but HELP_EVENT uses these to
+     record frame or window object and a help form, respectively.  */
   Lisp_Object x, y;
+
+  /* Usually a time as reported by window system-specific event loop.
+     For a HELP_EVENT, this is the position within the object (stored
+     in ARG below) where the help was found.  */
   Time timestamp;
 
   /* This field is copied into a vector while the event is in
      the queue, so that garbage collections won't kill it.  */
   Lisp_Object frame_or_window;
 
-  /* Additional event argument.  This is used for TOOL_BAR_EVENTs and
-     HELP_EVENTs and avoids calling Fcons during signal handling.  */
+  /* This additional argument is used in attempt to avoid extra consing
+     when building events.  Unfortunately some events have to pass much
+     more data than it's reasonable to pack directly into this structure.  */
   Lisp_Object arg;
 };
 
+/* To make sure we don't break HELP_EVENT.  */
+verify (sizeof (Time) == sizeof (ptrdiff_t));
+
 #define EVENT_INIT(event) memset (&(event), 0, sizeof (struct input_event))
 
 /* Bits in the modifiers member of the input_event structure.
diff --git a/src/w32inevt.c b/src/w32inevt.c
index ccb5a900a16..3dcae11cc48 100644
--- a/src/w32inevt.c
+++ b/src/w32inevt.c
@@ -411,7 +411,7 @@ w32_console_mouse_position (struct frame **f,
 
   *f = get_frame ();
   *bar_window = Qnil;
-  *part = 0;
+  *part = scroll_bar_above_handle;
   SELECTED_FRAME ()->mouse_moved = 0;
 
   XSETINT (*x, movement_pos.X);
diff --git a/src/w32term.c b/src/w32term.c
index 443f5ece8f0..0e10738e6f9 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -3448,7 +3448,7 @@ w32_mouse_position (struct frame **fp, int insist, Lisp_Object *bar_window,
             dpyinfo->last_mouse_glyph_frame = f1;
 
             *bar_window = Qnil;
-            *part = 0;
+            *part = scroll_bar_above_handle;
             *fp = f1;
             XSETINT (*x, pt.x);
             XSETINT (*y, pt.y);
diff --git a/src/xterm.c b/src/xterm.c
index e24e86ce412..89a7453b953 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -4157,7 +4157,7 @@ XTmouse_position (struct frame **fp, int insist, Lisp_Object *bar_window,
             dpyinfo->last_mouse_glyph_frame = f1;
 
             *bar_window = Qnil;
-            *part = 0;
+            *part = scroll_bar_above_handle;
             *fp = f1;
             XSETINT (*x, win_x);
             XSETINT (*y, win_y);
@@ -4250,7 +4250,8 @@ x_window_to_menu_bar (Window window)
 
 #ifdef USE_TOOLKIT_SCROLL_BARS
 
-static void x_send_scroll_bar_event (Lisp_Object, int, int, int, bool);
+static void x_send_scroll_bar_event (Lisp_Object, enum scroll_bar_part,
+                                     int, int, bool);
 
 /* Lisp window being scrolled.  Set when starting to interact with
    a toolkit scroll bar, reset to nil when ending the interaction.  */
@@ -4371,7 +4372,8 @@ xt_horizontal_action_hook (Widget widget, XtPointer client_data, String action_n
    amount to scroll of a whole of WHOLE.  */
 
 static void
-x_send_scroll_bar_event (Lisp_Object window, int part, int portion, int whole, bool horizontal)
+x_send_scroll_bar_event (Lisp_Object window, enum scroll_bar_part part,
+                         int portion, int whole, bool horizontal)
 {
   XEvent event;
   XClientMessageEvent *ev = &event.xclient;
@@ -4504,8 +4506,8 @@ xm_scroll_callback (Widget widget, XtPointer client_data, XtPointer call_data)
 {
   struct scroll_bar *bar = client_data;
   XmScrollBarCallbackStruct *cs = call_data;
-  int part = -1, whole = 0, portion = 0;
-  int horizontal = bar->horizontal;
+  enum scroll_bar_part part = scroll_bar_nowhere;
+  int horizontal = bar->horizontal, whole = 0, portion = 0;
 
   switch (cs->reason)
     {
@@ -4569,7 +4571,7 @@ xm_scroll_callback (Widget widget, XtPointer client_data, XtPointer call_data)
       break;
     };
 
-  if (part >= 0)
+  if (part != scroll_bar_nowhere)
     {
       window_being_scrolled = bar->window;
       x_send_scroll_bar_event (bar->window, part, portion, whole, bar->horizontal);
@@ -4587,8 +4589,9 @@ xg_scroll_callback (GtkRange     *range,
                     gdouble       value,
                     gpointer      user_data)
 {
+  int whole = 0, portion = 0;
   struct scroll_bar *bar = user_data;
-  int part = -1, whole = 0, portion = 0;
+  enum scroll_bar_part part = scroll_bar_nowhere;
   GtkAdjustment *adj = GTK_ADJUSTMENT (gtk_range_get_adjustment (range));
   struct frame *f = g_object_get_data (G_OBJECT (range), XG_FRAME_DATA);
 
@@ -4641,7 +4644,7 @@ xg_scroll_callback (GtkRange     *range,
       break;
     }
 
-  if (part >= 0)
+  if (part != scroll_bar_nowhere)
     {
       window_being_scrolled = bar->window;
       x_send_scroll_bar_event (bar->window, part, portion, whole, bar->horizontal);