Fix cursor motion across display strings covering reordered text.

 src/xdisp.c (set_cursor_from_row): Set start and stop points
 according to the row's direction when priming the loop that looks
 for the glyph on which to display cursor.
 (single_display_spec_intangible_p): Function deleted.
 (display_prop_intangible_p): Reimplement to call
 handle_display_spec instead of single_display_spec_intangible_p.
 Accept 3 additional arguments needed by handle_display_spec.  This
 fixes incorrect cursor motion across display property with complex
 values: lists, `(when COND...)' forms, etc.
 (single_display_spec_string_p): Support property values that are
 lists with the argument STRING its top-level element.
 (display_prop_string_p): Fix the condition for processing a
 property that is a list to be consistent with handle_display_spec.
 src/keyboard.c (adjust_point_for_property): Adjust the call to
 display_prop_intangible_p to its new signature.
 src/dispextern.h (display_prop_intangible_p): Adjust prototype.

4 files changed, 43 insertions, 77 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index b651856f276..12c0bde290b 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,8 +1,23 @@
 2011-05-28  Eli Zaretskii  <eliz@gnu.org>
 
-        * xdisp.c (set_cursor_from_row): Set start and stop points of the
-        loop that looks for the glyph on which to display cursor according
-        to the row's direction.
+        * xdisp.c (set_cursor_from_row): Set start and stop points
+        according to the row's direction when priming the loop that looks
+        for the glyph on which to display cursor.
+        (single_display_spec_intangible_p): Function deleted.
+        (display_prop_intangible_p): Reimplement to call
+        handle_display_spec instead of single_display_spec_intangible_p.
+        Accept 3 additional arguments needed by handle_display_spec.  This
+        fixes incorrect cursor motion across display property with complex
+        values: lists, `(when COND...)' forms, etc.
+        (single_display_spec_string_p): Support property values that are
+        lists with the argument STRING its top-level element.
+        (display_prop_string_p): Fix the condition for processing a
+        property that is a list to be consistent with handle_display_spec.
+
+        * keyboard.c (adjust_point_for_property): Adjust the call to
+        display_prop_intangible_p to its new signature.
+
+        * dispextern.h (display_prop_intangible_p): Adjust prototype.
 
 2011-05-21  Eli Zaretskii  <eliz@gnu.org>
 
diff --git a/src/dispextern.h b/src/dispextern.h
index 6c09f21a78f..7138c2225e8 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2957,7 +2957,7 @@ struct glyph_row *row_containing_pos (struct window *, EMACS_INT,
                                       struct glyph_row *,
                                       struct glyph_row *, int);
 int line_bottom_y (struct it *);
-int display_prop_intangible_p (Lisp_Object);
+int display_prop_intangible_p (Lisp_Object, Lisp_Object, EMACS_INT, EMACS_INT);
 void resize_echo_area_exactly (void);
 int resize_mini_window (struct window *, int);
 #if defined USE_TOOLKIT_SCROLL_BARS && !defined USE_GTK
diff --git a/src/keyboard.c b/src/keyboard.c
index a94456fce2e..ad4fd079049 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -1729,7 +1729,7 @@ adjust_point_for_property (EMACS_INT last_pt, int modified)
           && PT > BEGV && PT < ZV
           && !NILP (val = get_char_property_and_overlay
                               (make_number (PT), Qdisplay, Qnil, &overlay))
-          && display_prop_intangible_p (val)
+          && display_prop_intangible_p (val, overlay, PT, PT_BYTE)
           && (!OVERLAYP (overlay)
               ? get_property_and_range (PT, Qdisplay, &val, &beg, &end, Qnil)
               : (beg = OVERLAY_POSITION (OVERLAY_START (overlay)),
diff --git a/src/xdisp.c b/src/xdisp.c
index 9d5ec9f1f60..714c18be466 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -4375,83 +4375,31 @@ handle_single_display_spec (struct it *it, Lisp_Object spec, Lisp_Object object,
   return 0;
 }
 
-
-/* Check if SPEC is a display sub-property value whose text should be
-   treated as intangible.  */
-
-static int
-single_display_spec_intangible_p (Lisp_Object prop)
-{
-  /* Skip over `when FORM'.  */
-  if (CONSP (prop) && EQ (XCAR (prop), Qwhen))
-    {
-      prop = XCDR (prop);
-      if (!CONSP (prop))
-        return 0;
-      prop = XCDR (prop);
-    }
-
-  if (STRINGP (prop))
-    return 1;
-
-  if (!CONSP (prop))
-    return 0;
-
-  /* Skip over `margin LOCATION'.  If LOCATION is in the margins,
-     we don't need to treat text as intangible.  */
-  if (EQ (XCAR (prop), Qmargin))
-    {
-      prop = XCDR (prop);
-      if (!CONSP (prop))
-        return 0;
-
-      prop = XCDR (prop);
-      if (!CONSP (prop)
-          || EQ (XCAR (prop), Qleft_margin)
-          || EQ (XCAR (prop), Qright_margin))
-        return 0;
-    }
-
-  return (CONSP (prop)
-          && (EQ (XCAR (prop), Qimage)
-              || EQ (XCAR (prop), Qspace)));
-}
-
-
 /* Check if PROP is a display property value whose text should be
-   treated as intangible.  */
+   treated as intangible.  OVERLAY is the overlay from which PROP
+   came, or nil if it came from a text property.  CHARPOS and BYTEPOS
+   specify the buffer position covered by PROP.  */
 
 int
-display_prop_intangible_p (Lisp_Object prop)
+display_prop_intangible_p (Lisp_Object prop, Lisp_Object overlay,
+                           EMACS_INT charpos, EMACS_INT bytepos)
 {
-  if (CONSP (prop)
-      && CONSP (XCAR (prop))
-      && !EQ (Qmargin, XCAR (XCAR (prop))))
-    {
-      /* A list of sub-properties.  */
-      while (CONSP (prop))
-        {
-          if (single_display_spec_intangible_p (XCAR (prop)))
-            return 1;
-          prop = XCDR (prop);
-        }
-    }
-  else if (VECTORP (prop))
-    {
-      /* A vector of sub-properties.  */
-      int i;
-      for (i = 0; i < ASIZE (prop); ++i)
-        if (single_display_spec_intangible_p (AREF (prop, i)))
-          return 1;
-    }
-  else
-    return single_display_spec_intangible_p (prop);
+  int frame_window_p = FRAME_WINDOW_P (XFRAME (selected_frame));
+  struct text_pos position;
 
-  return 0;
+  SET_TEXT_POS (position, charpos, bytepos);
+  return handle_display_spec (NULL, prop, Qnil, overlay,
+                              &position, charpos, frame_window_p);
 }
 
 
-/* Return 1 if PROP is a display sub-property value containing STRING.  */
+/* Return 1 if PROP is a display sub-property value containing STRING.
+
+   Implementation note: this and the following function are really
+   special cases of handle_display_spec and
+   handle_single_display_spec, and should ideally use the same code.
+   Until they do, these two pairs must be consistent and must be
+   modified in sync.  */
 
 static int
 single_display_spec_string_p (Lisp_Object prop, Lisp_Object string)
@@ -4465,6 +4413,9 @@ single_display_spec_string_p (Lisp_Object prop, Lisp_Object string)
       prop = XCDR (prop);
       if (!CONSP (prop))
         return 0;
+      /* FIXME: We should eval the condition following `when', like
+         handle_single_display_spec does, and retrun zero if it
+         evaluates to nil.  */
       prop = XCDR (prop);
     }
 
@@ -4481,7 +4432,7 @@ single_display_spec_string_p (Lisp_Object prop, Lisp_Object string)
           return 0;
       }
 
-  return CONSP (prop) && EQ (XCAR (prop), string);
+  return EQ (prop, string) || (CONSP (prop) && EQ (XCAR (prop), string));
 }
 
 
@@ -4491,8 +4442,8 @@ static int
 display_prop_string_p (Lisp_Object prop, Lisp_Object string)
 {
   if (CONSP (prop)
-      && CONSP (XCAR (prop))
-      && !EQ (Qmargin, XCAR (XCAR (prop))))
+      && !EQ (XCAR (prop), Qwhen)
+      && !(CONSP (XCAR (prop)) && EQ (Qmargin, XCAR (XCAR (prop)))))
     {
       /* A list of sub-properties.  */
       while (CONSP (prop))