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bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents
From: |
Eli Zaretskii |
Subject: |
bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents |
Date: |
Sat, 30 Jun 2018 10:44:06 +0300 |
> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Cc: joaotavora@gmail.com, 31888@debbugs.gnu.org, k.michal@zoho.com, acm@muc.de
> Date: Fri, 29 Jun 2018 16:40:15 -0400
>
> IIUC replace-buffer-contents is meant to be used in cases where there's
> a good probability that the old and new contents are almost identical,
> save for a few details here and there.
>
> So, it may very well be the case that out of the 1MB that is covered by
> BEGV..ZV only 10bytes in the middle were deleted/inserted/modified, in
> which case running a-c-f on those 10bytes will likely lead to
> a significantly more efficient recomputation for things like font-lock.
>
> This refinement is not indispensable, but we make this effort in pretty
> much every other similar circumstance. It's usually fairly easy/cheap
> to provide those tighter bounds.
Sigh. Does the below look reasonable?
diff --git a/src/editfns.c b/src/editfns.c
index 4d3c838..9002211 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -3238,9 +3238,21 @@ differences between the two buffers. */)
Instead, we announce a single modification for the entire
modified region. But don't do that if the caller inhibited
modification hooks, because then they don't want that. */
+ ptrdiff_t from, to;
if (!inhibit_modification_hooks)
{
- prepare_to_modify_buffer (BEGV, ZV, NULL);
+ ptrdiff_t k, l;
+
+ /* Find the first character position to be changed. */
+ for (k = 0; k < size_a && !bit_is_set (ctx.deletions, k); k++)
+ ;
+ from = BEGV + k;
+
+ /* Find the last character position to be changed. */
+ for (l = size_a; l > 0 && !bit_is_set (ctx.deletions, l - 1); l--)
+ ;
+ to = BEGV + l;
+ prepare_to_modify_buffer (from, to, NULL);
specbind (Qinhibit_modification_hooks, Qt);
modification_hooks_inhibited = true;
}
@@ -3293,8 +3305,9 @@ differences between the two buffers. */)
if (modification_hooks_inhibited)
{
- signal_after_change (BEGV, size_a, ZV - BEGV);
- update_compositions (BEGV, ZV, CHECK_BORDER);
+ ptrdiff_t updated_to = to + ZV - BEGV - size_a;
+ signal_after_change (from, to - from, updated_to - from);
+ update_compositions (from, updated_to, CHECK_INSIDE);
}
return Qnil;
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, (continued)
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Eli Zaretskii, 2018/06/29
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Stefan Monnier, 2018/06/29
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Eli Zaretskii, 2018/06/29
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Eli Zaretskii, 2018/06/29
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, João Távora, 2018/06/29
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Eli Zaretskii, 2018/06/29
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, João Távora, 2018/06/30
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Eli Zaretskii, 2018/06/30
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, João Távora, 2018/06/30
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Stefan Monnier, 2018/06/29
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents,
Eli Zaretskii <=
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Stefan Monnier, 2018/06/30
- bug#31888: 27.0.50; Segmentation fault in replace-buffer-contents, Eli Zaretskii, 2018/06/30