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Re: subst-char-in-region broken when a before-change function reads buff
From: |
Stefan Monnier |
Subject: |
Re: subst-char-in-region broken when a before-change function reads buffer contents |
Date: |
Thu, 03 Aug 2006 11:59:27 -0400 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) |
> When I put a function calling buffer-substring into the
> before-change-functions hook, then subst-chars-in-region sometimes
> produces wrong results.
Good catch. Does the patch below help?
Stefan
--- orig/src/editfns.c
+++ mod/src/editfns.c
@@ -2706,6 +2706,10 @@
Lisp_Object start, end, fromchar, tochar, noundo;
{
register int pos, pos_byte, stop, i, len, end_byte;
+ /* Keep track of the first change in the buffer:
+ if 0 we haven't found it yet.
+ if < 0 we've found it and we've run the before-change-function.
+ if > 0 we've actually performed it and the value is its position. */
int changed = 0;
unsigned char fromstr[MAX_MULTIBYTE_LENGTH], tostr[MAX_MULTIBYTE_LENGTH];
unsigned char *p;
@@ -2718,6 +2722,8 @@
int last_changed = 0;
int multibyte_p = !NILP (current_buffer->enable_multibyte_characters);
+ restart:
+
validate_region (&start, &end);
CHECK_NUMBER (fromchar);
CHECK_NUMBER (tochar);
@@ -2755,7 +2761,7 @@
That's faster than getting rid of things,
and it prevents even the entry for a first change.
Also inhibit locking the file. */
- if (!NILP (noundo))
+ if (!changed && !NILP (noundo))
{
record_unwind_protect (subst_char_in_region_unwind,
current_buffer->undo_list);
@@ -2789,9 +2795,13 @@
&& (len == 2 || (p[2] == fromstr[2]
&& (len == 3 || p[3] == fromstr[3]))))))
{
- if (! changed)
+ if (changed < 0)
+ /* We've already seen this and run the before-change-function;
+ this time we only need to record the actual position. */
+ changed = pos;
+ else if (!changed)
{
- changed = pos;
- modify_region (current_buffer, changed, XINT (end));
+ changed = -1;
+ modify_region (current_buffer, pos, XINT (end));
if (! NILP (noundo))
@@ -2801,6 +2811,10 @@
if (MODIFF - 1 == current_buffer->auto_save_modified)
current_buffer->auto_save_modified++;
}
+
+ /* The before-change-function may have moved the gap
+ or even modified the buffer so we should start over. */
+ goto restart;
}
/* Take care of the case where the new character
@@ -2853,7 +2867,7 @@
pos++;
}
- if (changed)
+ if (changed > 0)
{
signal_after_change (changed,
last_changed - changed, last_changed - changed);