From: Jason Rumney <jasonr@f2s.com>
To: Jason Rumney <jasonr@f2s.com>, 716@emacsbugs.donarmstrong.com
Cc: Magnus Henoch <mange@freemail.hr>,
Stefan Monnier <monnier@IRO.UMontreal.CA>
Subject: bug#716: Bug in buffer-swap-text
Date: Tue, 23 Dec 2008 23:14:27 +0800 [thread overview]
Message-ID: <49510053.6020805@f2s.com> (raw)
In-Reply-To: <4950FAF6.808@f2s.com>
[-- Attachment #1: Type: text/plain, Size: 678 bytes --]
Jason Rumney wrote:
> Jason Rumney wrote:
>> One possible variable here is the way that buffer space is allocated.
>> On Windows, it seems REL_ALLOC is defined. I presume GNU/Linux
>> defines USE_MMAP_FOR_BUFFERS which would cause it to take a different
>> code path around the point where we see a crash on Windows, and as
>> Magnus Henoch saw on NetBSD/powerpc also (though we don't have a
>> stack trace for that crash, so can't tell for sure it is crashing in
>> the same place).
> The following patch seems to fix the problem, does it look correct to
> others who might understand ralloc.c and buffer_swap_text better than
> I do?
Sorry, once more with context:
[-- Attachment #2: bug716.diff --]
[-- Type: text/plain, Size: 2369 bytes --]
Index: buffer.c
===================================================================
RCS file: /sources/emacs/emacs/src/buffer.c,v
retrieving revision 1.575
diff -c -r1.575 buffer.c
*** buffer.c 9 Dec 2008 23:08:05 -0000 1.575
--- buffer.c 23 Dec 2008 14:37:33 -0000
***************
*** 2182,2187 ****
--- 2182,2192 ----
return byte_pos;
}
+ #ifdef REL_ALLOC
+ extern void r_alloc_prepare_to_swap_pointers P_ ((POINTER_TYPE **,
+ POINTER_TYPE **));
+ #endif
+
DEFUN ("buffer-swap-text", Fbuffer_swap_text, Sbuffer_swap_text,
1, 1, 0,
doc: /* Swap the text between current buffer and BUFFER. */)
***************
*** 2220,2225 ****
--- 2225,2235 ----
current_buffer->field = tmp##field; \
} while (0)
+ #ifdef REL_ALLOC
+ r_alloc_prepare_to_swap_pointers (¤t_buffer->own_text.beg,
+ &other_buffer->own_text.beg);
+ #endif
+
swapfield (own_text, struct buffer_text);
eassert (current_buffer->text == ¤t_buffer->own_text);
eassert (other_buffer->text == &other_buffer->own_text);
Index: ralloc.c
===================================================================
RCS file: /sources/emacs/emacs/src/ralloc.c,v
retrieving revision 1.69
diff -c -r1.69 ralloc.c
*** ralloc.c 21 Nov 2008 12:14:07 -0000 1.69
--- ralloc.c 23 Dec 2008 14:40:52 -0000
***************
*** 1223,1228 ****
--- 1223,1251 ----
#endif /* DEBUG */
+ /* Swap relocatable data between two pointers.
+ This is used by buffer_swap_text. Since buffer_swap_text swaps the
+ whole text structure in one go, this function has been written to only
+ update the internal pointers back to the variables, ready for when the
+ swap is actually done. It must be called before the pointers are
+ swapped so that the state is consistent when find_bloc is called. */
+ void
+ r_alloc_prepare_to_swap_pointers (p1, p2)
+ POINTER *p1, *p2;
+ {
+ bloc_ptr bloc1, bloc2;
+ bloc1 = find_bloc (p1);
+ bloc2 = find_bloc (p2);
+ if (bloc1 == NIL_BLOC || bloc2 == NIL_BLOC)
+ abort ();
+
+ /* Swap internal pointers back to the variables. */
+ bloc1->variable = p2;
+ bloc2->variable = p1;
+
+ /* It would be cleaner to do the actual swap here too, but it would
+ complicate buffer_swap_text. */
+ }
\f
/***********************************************************************
next prev parent reply other threads:[~2008-12-23 15:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-08 10:41 bug#716: Bug in buffer-swap-text Geoff Gole
2008-11-08 12:51 ` Magnus Henoch
2008-12-02 22:58 ` Stefan Monnier
2008-12-03 0:11 ` jasonr
2008-12-03 2:44 ` Stefan Monnier
2008-12-03 2:55 ` jasonr
2008-12-23 12:45 ` Jason Rumney
2008-12-23 14:51 ` Jason Rumney
2008-12-23 15:14 ` Jason Rumney [this message]
2008-12-23 17:23 ` Stefan Monnier
2008-12-23 23:15 ` Jason Rumney
2008-12-24 1:17 ` jasonr
2008-12-24 2:41 ` Stefan Monnier
-- strict thread matches above, loose matches on Subject: below --
2008-12-03 15:25 Geoff Gole
2008-12-03 15:42 ` Jason Rumney
2008-12-03 15:46 ` Geoff Gole
2008-12-03 20:42 ` Stefan Monnier
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