Fix vertical cursor motion when there's a display string with newline at EOL.

 src/xdisp.c (row_for_charpos_p): New function, with code of
 cursor_row_p, but accepts an additional argument CHARPOS instead
 of using a hardcoded PT.
 (cursor_row_p): Call row_for_charpos_p with 2nd argument PT.
 (row_containing_pos): Call row_for_charpos_p instead of partially
 doing the same.  Fixes cursor positioning under longlines-mode
 when longlines-show-effect includes more than one newline, when
 moving the cursor vertically up.

2 files changed, 33 insertions, 13 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 64b76af0b85..c8e2abf3bec 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,14 @@
+2013-05-08  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (row_for_charpos_p): New function, with code of
+        cursor_row_p, but accepts an additional argument CHARPOS instead
+        of using a hardcoded PT.
+        (cursor_row_p): Call row_for_charpos_p with 2nd argument PT.
+        (row_containing_pos): Call row_for_charpos_p instead of partially
+        doing the same.  Fixes cursor positioning under longlines-mode
+        when longlines-show-effect includes more than one newline, when
+        moving the cursor vertically up.
+
 2013-05-08  Juanma Barranquero  <lekktu@gmail.com>
 
         * makefile.w32-in (ACL_H): New macro.
diff --git a/src/xdisp.c b/src/xdisp.c
index c7a25873272..0a79e6fd891 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -794,6 +794,7 @@ static void set_iterator_to_next (struct it *, int);
 static void mark_window_display_accurate_1 (struct window *, int);
 static int single_display_spec_string_p (Lisp_Object, Lisp_Object);
 static int display_prop_string_p (Lisp_Object, Lisp_Object);
+static int row_for_charpos_p (struct glyph_row *, ptrdiff_t);
 static int cursor_row_p (struct glyph_row *);
 static int redisplay_mode_lines (Lisp_Object, int);
 static char *decode_mode_spec_coding (Lisp_Object, char *, int);
@@ -16909,10 +16910,9 @@ row_containing_pos (struct window *w, ptrdiff_t charpos,
              || (MATRIX_ROW_END_CHARPOS (row) == charpos
                  /* The end position of a row equals the start
                     position of the next row.  If CHARPOS is there, we
-                    would rather display it in the next line, except
-                    when this line ends in ZV.  */
-                 && !row->ends_at_zv_p
-                 && !MATRIX_ROW_ENDS_IN_MIDDLE_OF_CHAR_P (row)))
+                    would rather consider it displayed in the next
+                    line, except when this line ends in ZV.  */
+                 && !row_for_charpos_p (row, charpos)))
           && charpos >= MATRIX_ROW_START_CHARPOS (row))
         {
           struct glyph *g;
@@ -16920,10 +16920,10 @@ row_containing_pos (struct window *w, ptrdiff_t charpos,
           if (NILP (BVAR (XBUFFER (w->contents), bidi_display_reordering))
               || (!best_row && !row->continued_p))
             return row;
-          /* In bidi-reordered rows, there could be several rows
-             occluding point, all of them belonging to the same
-             continued line.  We need to find the row which fits
-             CHARPOS the best.  */
+          /* In bidi-reordered rows, there could be several rows whose
+             edges surround CHARPOS, all of these rows belonging to
+             the same continued line.  We need to find the row which
+             fits CHARPOS the best.  */
           for (g = row->glyphs[TEXT_AREA];
                g < row->glyphs[TEXT_AREA] + row->used[TEXT_AREA];
                g++)
@@ -18727,15 +18727,15 @@ highlight_trailing_whitespace (struct frame *f, struct glyph_row *row)
 
 
 /* Value is non-zero if glyph row ROW should be
-   used to hold the cursor.  */
+   considered to hold the buffer position CHARPOS.  */
 
 static int
-cursor_row_p (struct glyph_row *row)
+row_for_charpos_p (struct glyph_row *row, ptrdiff_t charpos)
 {
   int result = 1;
 
-  if (PT == CHARPOS (row->end.pos)
-      || PT == MATRIX_ROW_END_CHARPOS (row))
+  if (charpos == CHARPOS (row->end.pos)
+      || charpos == MATRIX_ROW_END_CHARPOS (row))
     {
       /* Suppose the row ends on a string.
          Unless the row is continued, that means it ends on a newline
@@ -18761,7 +18761,7 @@ cursor_row_p (struct glyph_row *row)
                 if (STRINGP (glyph->object))
                   {
                     Lisp_Object prop
-                      = Fget_char_property (make_number (PT),
+                      = Fget_char_property (make_number (charpos),
                                             Qdisplay, Qnil);
                     result =
                       (!NILP (prop)
@@ -18815,6 +18815,15 @@ cursor_row_p (struct glyph_row *row)
   return result;
 }
 
+/* Value is non-zero if glyph row ROW should be
+   used to hold the cursor.  */
+
+static int
+cursor_row_p (struct glyph_row *row)
+{
+  return row_for_charpos_p (row, PT);
+}
+
 
 
 /* Push the property PROP so that it will be rendered at the current