(single_display_spec_string_p): Renamed from

single_display_prop_string_p.
(single_display_spec_intangible_p): Renamed from
single_display_prop_intangible_p.
(handle_single_display_spec): Renamed from handle_single_display_prop.
Rewritten to be easier to understand.

1 files changed, 220 insertions, 197 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 2b97866592e..8ed0adfc89e 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -814,7 +814,7 @@ static struct glyph_slice null_glyph_slice = { 0, 0, 0, 0 };
 
 static void setup_for_ellipsis P_ ((struct it *, int));
 static void mark_window_display_accurate_1 P_ ((struct window *, int));
-static int single_display_prop_string_p P_ ((Lisp_Object, Lisp_Object));
+static int single_display_spec_string_p P_ ((Lisp_Object, Lisp_Object));
 static int display_prop_string_p P_ ((Lisp_Object, Lisp_Object));
 static int cursor_row_p P_ ((struct window *, struct glyph_row *));
 static int redisplay_mode_lines P_ ((Lisp_Object, int));
@@ -836,7 +836,7 @@ static int store_frame_title P_ ((const unsigned char *, int, int));
 static void x_consider_frame_title P_ ((Lisp_Object));
 static void handle_stop P_ ((struct it *));
 static int tool_bar_lines_needed P_ ((struct frame *));
-static int single_display_prop_intangible_p P_ ((Lisp_Object));
+static int single_display_spec_intangible_p P_ ((Lisp_Object));
 static void ensure_echo_area_buffers P_ ((void));
 static Lisp_Object unwind_with_echo_area_buffer P_ ((Lisp_Object));
 static Lisp_Object with_echo_area_buffer_unwind_data P_ ((struct window *));
@@ -930,7 +930,7 @@ static void compute_string_pos P_ ((struct text_pos *, struct text_pos,
                                     Lisp_Object));
 static int face_before_or_after_it_pos P_ ((struct it *, int));
 static int next_overlay_change P_ ((int));
-static int handle_single_display_prop P_ ((struct it *, Lisp_Object,
+static int handle_single_display_spec P_ ((struct it *, Lisp_Object,
                                            Lisp_Object, struct text_pos *,
                                            int));
 static int underlying_face_id P_ ((struct it *));
@@ -3279,7 +3279,10 @@ setup_for_ellipsis (it, len)
  ***********************************************************************/
 
 /* Set up iterator IT from `display' property at its current position.
-   Called from handle_stop.  */
+   Called from handle_stop.
+   We return HANDLED_RETURN if some part of the display property
+   overrides the display of the buffer text itself.
+   Otherwise we return HANDLED_NORMALLY.  */
 
 static enum prop_handled
 handle_display_prop (it)
@@ -3287,6 +3290,7 @@ handle_display_prop (it)
 {
   Lisp_Object prop, object;
   struct text_pos *position;
+  /* Nonzero if some property replaces the display of the text itself.  */ 
   int display_replaced_p = 0;
 
   if (STRINGP (it->string))
@@ -3334,7 +3338,7 @@ handle_display_prop (it)
     {
       for (; CONSP (prop); prop = XCDR (prop))
         {
-          if (handle_single_display_prop (it, XCAR (prop), object,
+          if (handle_single_display_spec (it, XCAR (prop), object,
                                           position, display_replaced_p))
             display_replaced_p = 1;
         }
@@ -3343,13 +3347,13 @@ handle_display_prop (it)
     {
       int i;
       for (i = 0; i < ASIZE (prop); ++i)
-        if (handle_single_display_prop (it, AREF (prop, i), object,
+        if (handle_single_display_spec (it, AREF (prop, i), object,
                                         position, display_replaced_p))
           display_replaced_p = 1;
     }
   else
     {
-      if (handle_single_display_prop (it, prop, object, position, 0))
+      if (handle_single_display_spec (it, prop, object, position, 0))
         display_replaced_p = 1;
     }
 
@@ -3381,42 +3385,44 @@ display_prop_end (it, object, start_pos)
 }
 
 
-/* Set up IT from a single `display' sub-property value PROP.  OBJECT
+/* Set up IT from a single `display' specification PROP.  OBJECT
    is the object in which the `display' property was found.  *POSITION
    is the position at which it was found.  DISPLAY_REPLACED_P non-zero
-   means that we previously saw a display sub-property which already
+   means that we previously saw a display specification which already
    replaced text display with something else, for example an image;
-   ignore such properties after the first one has been processed.
+   we ignore such properties after the first one has been processed.
 
-   If PROP is a `space' or `image' sub-property, set *POSITION to the
-   end position of the `display' property.
+   If PROP is a `space' or `image' specification, and in some other
+   cases too, set *POSITION to the position where the `display'
+   property ends.
 
    Value is non-zero if something was found which replaces the display
    of buffer or string text.  */
 
 static int
-handle_single_display_prop (it, prop, object, position,
+handle_single_display_spec (it, spec, object, position,
                             display_replaced_before_p)
      struct it *it;
-     Lisp_Object prop;
+     Lisp_Object spec;
      Lisp_Object object;
      struct text_pos *position;
      int display_replaced_before_p;
 {
-  Lisp_Object value;
-  int replaces_text_display_p = 0;
   Lisp_Object form;
+  Lisp_Object location, value;
+  struct text_pos start_pos;
+  int valid_p;
 
-  /* If PROP is a list of the form `(when FORM . VALUE)', FORM is
-     evaluated.  If the result is nil, VALUE is ignored.  */
+  /* If SPEC is a list of the form `(when FORM . VALUE)', evaluate FORM.
+     If the result is non-nil, use VALUE instead of SPEC.  */
   form = Qt;
-  if (CONSP (prop) && EQ (XCAR (prop), Qwhen))
+  if (CONSP (spec) && EQ (XCAR (spec), Qwhen))
     {
-      prop = XCDR (prop);
-      if (!CONSP (prop))
+      spec = XCDR (spec);
+      if (!CONSP (spec))
         return 0;
-      form = XCAR (prop);
-      prop = XCDR (prop);
+      form = XCAR (spec);
+      spec = XCDR (spec);
     }
 
   if (!NILP (form) && !EQ (form, Qt))
@@ -3442,15 +3448,15 @@ handle_single_display_prop (it, prop, object, position,
   if (NILP (form))
     return 0;
 
-  if (CONSP (prop)
-      && EQ (XCAR (prop), Qheight)
-      && CONSP (XCDR (prop)))
+  /* Handle `(height HEIGHT)' specifications.  */
+  if (CONSP (spec)
+      && EQ (XCAR (spec), Qheight)
+      && CONSP (XCDR (spec)))
     {
       if (FRAME_TERMCAP_P (it->f) || FRAME_MSDOS_P (it->f))
         return 0;
-
-      /* `(height HEIGHT)'.  */
-      it->font_height = XCAR (XCDR (prop));
+      
+      it->font_height = XCAR (XCDR (spec));
       if (!NILP (it->font_height))
         {
           struct face *face = FACE_FROM_ID (it->f, it->face_id);
@@ -3491,7 +3497,6 @@ handle_single_display_prop (it, prop, object, position,
             {
               /* Evaluate IT->font_height with `height' bound to the
                  current specified height to get the new height.  */
-              Lisp_Object value;
               int count = SPECPDL_INDEX ();
 
               specbind (Qheight, face->lface[LFACE_HEIGHT_INDEX]);
@@ -3505,29 +3510,35 @@ handle_single_display_prop (it, prop, object, position,
           if (new_height > 0)
             it->face_id = face_with_height (it->f, it->face_id, new_height);
         }
+
+      return 0;
     }
-  else if (CONSP (prop)
-           && EQ (XCAR (prop), Qspace_width)
-           && CONSP (XCDR (prop)))
+
+  /* Handle `(space_width WIDTH)'.  */
+  if (CONSP (spec)
+      && EQ (XCAR (spec), Qspace_width)
+      && CONSP (XCDR (spec)))
     {
-      /* `(space_width WIDTH)'.  */
       if (FRAME_TERMCAP_P (it->f) || FRAME_MSDOS_P (it->f))
         return 0;
 
-      value = XCAR (XCDR (prop));
+      value = XCAR (XCDR (spec));
       if (NUMBERP (value) && XFLOATINT (value) > 0)
         it->space_width = value;
+
+      return 0;
     }
-  else if (CONSP (prop)
-           && EQ (XCAR (prop), Qslice))
+
+  /* Handle `(slice X Y WIDTH HEIGHT)'.  */
+  if (CONSP (spec)
+      && EQ (XCAR (spec), Qslice))
     {
-      /* `(slice X Y WIDTH HEIGHT)'.  */
       Lisp_Object tem;
 
       if (FRAME_TERMCAP_P (it->f) || FRAME_MSDOS_P (it->f))
         return 0;
 
-      if (tem = XCDR (prop), CONSP (tem))
+      if (tem = XCDR (spec), CONSP (tem))
         {
           it->slice.x = XCAR (tem);
           if (tem = XCDR (tem), CONSP (tem))
@@ -3541,17 +3552,20 @@ handle_single_display_prop (it, prop, object, position,
                 }
             }
         }
+
+      return 0;
     }
-  else if (CONSP (prop)
-           && EQ (XCAR (prop), Qraise)
-           && CONSP (XCDR (prop)))
+
+  /* Handle `(raise FACTOR)'.  */
+  if (CONSP (spec)
+      && EQ (XCAR (spec), Qraise)
+      && CONSP (XCDR (spec)))
     {
-      /* `(raise FACTOR)'.  */
       if (FRAME_TERMCAP_P (it->f) || FRAME_MSDOS_P (it->f))
         return 0;
 
 #ifdef HAVE_WINDOW_SYSTEM
-      value = XCAR (XCDR (prop));
+      value = XCAR (XCDR (spec));
       if (NUMBERP (value))
         {
           struct face *face = FACE_FROM_ID (it->f, it->face_id);
@@ -3559,185 +3573,194 @@ handle_single_display_prop (it, prop, object, position,
                            * (FONT_HEIGHT (face->font)));
         }
 #endif /* HAVE_WINDOW_SYSTEM */
+
+      return 0;
     }
-  else if (!it->string_from_display_prop_p)
-    {
-      /* `((margin left-margin) VALUE)' or `((margin right-margin)
-         VALUE) or `((margin nil) VALUE)' or VALUE.  */
-      Lisp_Object location, value;
-      struct text_pos start_pos;
-      int valid_p;
 
-      /* Characters having this form of property are not displayed, so
-         we have to find the end of the property.  */
-      start_pos = *position;
-      *position = display_prop_end (it, object, start_pos);
-      value = Qnil;
+  /* Don't handle the other kinds of display specifications
+     inside a string that we got from a `display' property.  */
+  if (it->string_from_display_prop_p)
+    return 0;
 
-      /* Let's stop at the new position and assume that all
-         text properties change there.  */
-      it->stop_charpos = position->charpos;
+  /* Characters having this form of property are not displayed, so
+     we have to find the end of the property.  */
+  start_pos = *position;
+  *position = display_prop_end (it, object, start_pos);
+  value = Qnil;
 
-      if (CONSP (prop)
-          && (EQ (XCAR (prop), Qleft_fringe)
-              || EQ (XCAR (prop), Qright_fringe))
-          && CONSP (XCDR (prop)))
-        {
-          int face_id = DEFAULT_FACE_ID;
-          int fringe_bitmap;
+  /* Stop the scan at that end position--we assume that all
+     text properties change there.  */
+  it->stop_charpos = position->charpos;
 
-          /* Save current settings of IT so that we can restore them
-             when we are finished with the glyph property value.  */
+  /* Handle `(left-fringe BITMAP [FACE])'
+     and `(right-fringe BITMAP [FACE])'.  */
+  if (CONSP (spec)
+      && (EQ (XCAR (spec), Qleft_fringe)
+          || EQ (XCAR (spec), Qright_fringe))
+      && CONSP (XCDR (spec)))
+    {
+      int face_id = DEFAULT_FACE_ID;
+      int fringe_bitmap;
 
-          /* `(left-fringe BITMAP FACE)'.  */
-          if (FRAME_TERMCAP_P (it->f) || FRAME_MSDOS_P (it->f))
-            return 0;
+      if (FRAME_TERMCAP_P (it->f) || FRAME_MSDOS_P (it->f))
+        /* If we return here, POSITION has been advanced
+           across the text with this property.  */
+        return 0;
 
 #ifdef HAVE_WINDOW_SYSTEM
-          value = XCAR (XCDR (prop));
-          if (!SYMBOLP (value)
-              || !(fringe_bitmap = lookup_fringe_bitmap (value)))
-            return 0;
+      value = XCAR (XCDR (spec));
+      if (!SYMBOLP (value)
+          || !(fringe_bitmap = lookup_fringe_bitmap (value)))
+        /* If we return here, POSITION has been advanced
+           across the text with this property.  */
+        return 0;
 
-          if (CONSP (XCDR (XCDR (prop))))
-            {
-              Lisp_Object face_name = XCAR (XCDR (XCDR (prop)));
-              int face_id2 = lookup_named_face (it->f, face_name, 'A', 0);
-              if (face_id2 >= 0)
-                face_id = face_id2;
-            }
+      if (CONSP (XCDR (XCDR (spec))))
+        {
+          Lisp_Object face_name = XCAR (XCDR (XCDR (spec)));
+          int face_id2 = lookup_named_face (it->f, face_name, 'A', 0);
+          if (face_id2 >= 0)
+            face_id = face_id2;
+        }
 
-          push_it (it);
+      /* Save current settings of IT so that we can restore them
+         when we are finished with the glyph property value.  */
 
-          it->area = TEXT_AREA;
-          it->what = IT_IMAGE;
-          it->image_id = -1; /* no image */
-          it->position = start_pos;
-          it->object = NILP (object) ? it->w->buffer : object;
-          it->method = next_element_from_image;
-          it->face_id = face_id;
+      push_it (it);
 
-          /* Say that we haven't consumed the characters with
-             `display' property yet.  The call to pop_it in
-             set_iterator_to_next will clean this up.  */
-          *position = start_pos;
+      it->area = TEXT_AREA;
+      it->what = IT_IMAGE;
+      it->image_id = -1; /* no image */
+      it->position = start_pos;
+      it->object = NILP (object) ? it->w->buffer : object;
+      it->method = next_element_from_image;
+      it->face_id = face_id;
 
-          if (EQ (XCAR (prop), Qleft_fringe))
-            {
-              it->left_user_fringe_bitmap = fringe_bitmap;
-              it->left_user_fringe_face_id = face_id;
-            }
-          else
-            {
-              it->right_user_fringe_bitmap = fringe_bitmap;
-              it->right_user_fringe_face_id = face_id;
-            }
-#endif /* HAVE_WINDOW_SYSTEM */
-          return 1;
-        }
+      /* Say that we haven't consumed the characters with
+         `display' property yet.  The call to pop_it in
+         set_iterator_to_next will clean this up.  */
+      *position = start_pos;
 
-      location = Qunbound;
-      if (CONSP (prop) && CONSP (XCAR (prop)))
+      if (EQ (XCAR (spec), Qleft_fringe))
         {
-          Lisp_Object tem;
-
-          value = XCDR (prop);
-          if (CONSP (value))
-            value = XCAR (value);
-
-          tem = XCAR (prop);
-          if (EQ (XCAR (tem), Qmargin)
-              && (tem = XCDR (tem),
-                  tem = CONSP (tem) ? XCAR (tem) : Qnil,
-                  (NILP (tem)
-                   || EQ (tem, Qleft_margin)
-                   || EQ (tem, Qright_margin))))
-            location = tem;
+          it->left_user_fringe_bitmap = fringe_bitmap;
+          it->left_user_fringe_face_id = face_id;
         }
-
-      if (EQ (location, Qunbound))
+      else
         {
-          location = Qnil;
-          value = prop;
+          it->right_user_fringe_bitmap = fringe_bitmap;
+          it->right_user_fringe_face_id = face_id;
         }
+#endif /* HAVE_WINDOW_SYSTEM */
+      return 1;
+    }
 
-      valid_p = (STRINGP (value)
-#ifdef HAVE_WINDOW_SYSTEM
-                 || (!FRAME_TERMCAP_P (it->f) && valid_image_p (value))
-#endif /* not HAVE_WINDOW_SYSTEM */
-                 || (CONSP (value) && EQ (XCAR (value), Qspace)));
+  /* Prepare to handle `((margin left-margin) ...)',
+     `((margin right-margin) ...)' and `((margin nil) ...)'
+     prefixes for display specifications.  */
+  location = Qunbound;
+  if (CONSP (spec) && CONSP (XCAR (spec)))
+    {
+      Lisp_Object tem;
 
-      if ((EQ (location, Qleft_margin)
-           || EQ (location, Qright_margin)
-           || NILP (location))
-          && valid_p
-          && !display_replaced_before_p)
-        {
-          replaces_text_display_p = 1;
+      value = XCDR (spec);
+      if (CONSP (value))
+        value = XCAR (value);
 
-          /* Save current settings of IT so that we can restore them
-             when we are finished with the glyph property value.  */
-          push_it (it);
+      tem = XCAR (spec);
+      if (EQ (XCAR (tem), Qmargin)
+          && (tem = XCDR (tem),
+              tem = CONSP (tem) ? XCAR (tem) : Qnil,
+              (NILP (tem)
+               || EQ (tem, Qleft_margin)
+               || EQ (tem, Qright_margin))))
+        location = tem;
+    }
 
-          if (NILP (location))
-            it->area = TEXT_AREA;
-          else if (EQ (location, Qleft_margin))
-            it->area = LEFT_MARGIN_AREA;
-          else
-            it->area = RIGHT_MARGIN_AREA;
+  if (EQ (location, Qunbound))
+    {
+      location = Qnil;
+      value = spec;
+    }
 
-          if (STRINGP (value))
-            {
-              it->string = value;
-              it->multibyte_p = STRING_MULTIBYTE (it->string);
-              it->current.overlay_string_index = -1;
-              IT_STRING_CHARPOS (*it) = IT_STRING_BYTEPOS (*it) = 0;
-              it->end_charpos = it->string_nchars = SCHARS (it->string);
-              it->method = next_element_from_string;
-              it->stop_charpos = 0;
-              it->string_from_display_prop_p = 1;
-              /* Say that we haven't consumed the characters with
-                 `display' property yet.  The call to pop_it in
-                 set_iterator_to_next will clean this up.  */
-              *position = start_pos;
-            }
-          else if (CONSP (value) && EQ (XCAR (value), Qspace))
-            {
-              it->method = next_element_from_stretch;
-              it->object = value;
-              it->current.pos = it->position = start_pos;
-            }
+  /* After this point, VALUE is the property after any
+     margin prefix has been stripped.  It must be a string,
+     an image specification, or `(space ...)'.
+
+     LOCATION specifies where to display: `left-margin',
+     `right-margin' or nil.  */
+
+  valid_p = (STRINGP (value)
 #ifdef HAVE_WINDOW_SYSTEM
-          else
-            {
-              it->what = IT_IMAGE;
-              it->image_id = lookup_image (it->f, value);
-              it->position = start_pos;
-              it->object = NILP (object) ? it->w->buffer : object;
-              it->method = next_element_from_image;
-
-              /* Say that we haven't consumed the characters with
-                 `display' property yet.  The call to pop_it in
-                 set_iterator_to_next will clean this up.  */
-              *position = start_pos;
-            }
-#endif /* HAVE_WINDOW_SYSTEM */
+             || (!FRAME_TERMCAP_P (it->f) && valid_image_p (value))
+#endif /* not HAVE_WINDOW_SYSTEM */
+             || (CONSP (value) && EQ (XCAR (value), Qspace)));
+
+  if (valid_p && !display_replaced_before_p)
+    {
+      /* Save current settings of IT so that we can restore them
+         when we are finished with the glyph property value.  */
+      push_it (it);
+
+      if (NILP (location))
+        it->area = TEXT_AREA;
+      else if (EQ (location, Qleft_margin))
+        it->area = LEFT_MARGIN_AREA;
+      else
+        it->area = RIGHT_MARGIN_AREA;
+
+      if (STRINGP (value))
+        {
+          it->string = value;
+          it->multibyte_p = STRING_MULTIBYTE (it->string);
+          it->current.overlay_string_index = -1;
+          IT_STRING_CHARPOS (*it) = IT_STRING_BYTEPOS (*it) = 0;
+          it->end_charpos = it->string_nchars = SCHARS (it->string);
+          it->method = next_element_from_string;
+          it->stop_charpos = 0;
+          it->string_from_display_prop_p = 1;
+          /* Say that we haven't consumed the characters with
+             `display' property yet.  The call to pop_it in
+             set_iterator_to_next will clean this up.  */
+          *position = start_pos;
         }
+      else if (CONSP (value) && EQ (XCAR (value), Qspace))
+        {
+          it->method = next_element_from_stretch;
+          it->object = value;
+          it->current.pos = it->position = start_pos;
+        }
+#ifdef HAVE_WINDOW_SYSTEM
       else
-        /* Invalid property or property not supported.  Restore
-           the position to what it was before.  */
-        *position = start_pos;
+        {
+          it->what = IT_IMAGE;
+          it->image_id = lookup_image (it->f, value);
+          it->position = start_pos;
+          it->object = NILP (object) ? it->w->buffer : object;
+          it->method = next_element_from_image;
+
+          /* Say that we haven't consumed the characters with
+             `display' property yet.  The call to pop_it in
+             set_iterator_to_next will clean this up.  */
+          *position = start_pos;
+        }
+#endif /* HAVE_WINDOW_SYSTEM */
+
+      return 1;
     }
 
-  return replaces_text_display_p;
+  /* Invalid property or property not supported.  Restore
+     POSITION to what it was before.  */
+  *position = start_pos;
+  return 0;
 }
 
 
-/* Check if PROP is a display sub-property value whose text should be
+/* Check if SPEC is a display specification value whose text should be
    treated as intangible.  */
 
 static int
-single_display_prop_intangible_p (prop)
+single_display_spec_intangible_p (prop)
      Lisp_Object prop;
 {
   /* Skip over `when FORM'.  */
@@ -3790,7 +3813,7 @@ display_prop_intangible_p (prop)
       /* A list of sub-properties.  */
       while (CONSP (prop))
         {
-          if (single_display_prop_intangible_p (XCAR (prop)))
+          if (single_display_spec_intangible_p (XCAR (prop)))
             return 1;
           prop = XCDR (prop);
         }
@@ -3800,11 +3823,11 @@ display_prop_intangible_p (prop)
       /* A vector of sub-properties.  */
       int i;
       for (i = 0; i < ASIZE (prop); ++i)
-        if (single_display_prop_intangible_p (AREF (prop, i)))
+        if (single_display_spec_intangible_p (AREF (prop, i)))
           return 1;
     }
   else
-    return single_display_prop_intangible_p (prop);
+    return single_display_spec_intangible_p (prop);
 
   return 0;
 }
@@ -3813,7 +3836,7 @@ display_prop_intangible_p (prop)
 /* Return 1 if PROP is a display sub-property value containing STRING.  */
 
 static int
-single_display_prop_string_p (prop, string)
+single_display_spec_string_p (prop, string)
      Lisp_Object prop, string;
 {
   if (EQ (string, prop))
@@ -3858,7 +3881,7 @@ display_prop_string_p (prop, string)
       /* A list of sub-properties.  */
       while (CONSP (prop))
         {
-          if (single_display_prop_string_p (XCAR (prop), string))
+          if (single_display_spec_string_p (XCAR (prop), string))
             return 1;
           prop = XCDR (prop);
         }
@@ -3868,11 +3891,11 @@ display_prop_string_p (prop, string)
       /* A vector of sub-properties.  */
       int i;
       for (i = 0; i < ASIZE (prop); ++i)
-        if (single_display_prop_string_p (AREF (prop, i), string))
+        if (single_display_spec_string_p (AREF (prop, i), string))
           return 1;
     }
   else
-    return single_display_prop_string_p (prop, string);
+    return single_display_spec_string_p (prop, string);
 
   return 0;
 }
@@ -6625,7 +6648,7 @@ message_log_check_duplicate (prev_bol, prev_bol_byte, this_bol, this_bol_byte)
     }
   return 0;
 }
-
+
 
 /* Display an echo area message M with a specified length of NBYTES
    bytes.  The string may include null characters.  If M is 0, clear