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Fix bug #9624 with crashes in Muse mode.

Browse source 
src/xdisp.c (compute_display_string_end): If there's no display
 string at CHARPOS, return -1.
 src/bidi.c (bidi_fetch_char): When compute_display_string_end
 returns a negative value, treat the character as a normal
 character not covered by a display string.
This commit is contained in:
Eli Zaretskii 2011-09-28 17:37:27 +03:00
parent 0a40c0609b
commit fbcaa2f388
3 changed files with 38 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

9
src/ChangeLog
View file

@ -1,3 +1,12 @@
2011-09-28 Eli Zaretskii <eliz@gnu.org>
* xdisp.c (compute_display_string_end): If there's no display
string at CHARPOS, return -1.
* bidi.c (bidi_fetch_char): When compute_display_string_end
returns a negative value, treat the character as a normal
character not covered by a display string. (Bug#9624)
2011-09-28 Juanma Barranquero <lekktu@gmail.com>
* lread.c (Fread_from_string): Fix typo in docstring.

10
src/bidi.c
View file

@ -974,6 +974,15 @@ bidi_fetch_char (EMACS_INT bytepos, EMACS_INT charpos, EMACS_INT *disp_pos,
ch = 0xFFFC;
}
disp_end_pos = compute_display_string_end (*disp_pos, string);
if (disp_end_pos < 0)
{
/* Somebody removed the display string from the buffer
behind our back. Recover by processing this buffer
position as if no display property were present there to
begin with. */
*disp_prop = 0;
goto normal_char;
}
*nchars = disp_end_pos - *disp_pos;
if (*nchars <= 0)
abort ();
@ -988,6 +997,7 @@ bidi_fetch_char (EMACS_INT bytepos, EMACS_INT charpos, EMACS_INT *disp_pos,
}
else
{
normal_char:
if (string->s)
{
int len;

23
src/xdisp.c
View file

@ -3386,9 +3386,10 @@ compute_display_string_pos (struct text_pos *position,
}
/* Return the character position of the end of the display string that
started at CHARPOS. A display string is either an overlay with
`display' property whose value is a string or a `display' text
property whose value is a string. */
started at CHARPOS. If there's no display string at CHARPOS,
return -1. A display string is either an overlay with `display'
property whose value is a string or a `display' text property whose
value is a string. */
EMACS_INT
compute_display_string_end (EMACS_INT charpos, struct bidi_string_data *string)
{
@ -3402,8 +3403,22 @@ compute_display_string_end (EMACS_INT charpos, struct bidi_string_data *string)
if (charpos >= eob || (string->s && !STRINGP (object)))
return eob;
/* It could happen that the display property or overlay was removed
since we found it in compute_display_string_pos above. One way
this can happen is if JIT font-lock was called (through
handle_fontified_prop), and jit-lock-functions remove text
properties or overlays from the portion of buffer that includes
CHARPOS. Muse mode is known to do that, for example. In this
case, we return -1 to the caller, to signal that no display
string is actually present at CHARPOS. See bidi_fetch_char for
how this is handled.
An alternative would be to never look for display properties past
it->stop_charpos. But neither compute_display_string_pos nor
bidi_fetch_char that calls it know or care where the next
stop_charpos is. */
if (NILP (Fget_char_property (pos, Qdisplay, object)))
abort ();
return -1;
/* Look forward for the first character where the `display' property
changes. */