Mercurial > hg
annotate mercurial/strutil.py @ 26375:3686fa2b8eee
windows: insert file positioning call between reads and writes
fopen() and fdopen() have a unique-to-Windows requirement that
transitions between read and write operations in files opened
in modes r+, w+, and a+ perform a file positioning call
(fsetpos, fseek, or rewind) in between. While the MSDN docs don't
say what will happen if this is not done, observations reveal
that Python raises an IOError with errno 0. Furthermore, I
/think/ this behavior isn't deterministic. But I can reproduce
it reliably with subsequent patches applied that open revlogs
in a+ mode and perform both reads and writes.
This patch introduces a proxy class for file handles opened
in r+, w+, and a+ mode on Windows. The class intercepts calls
and audits whether a file positioning function has been called
between read and write operations. If not, a dummy, no-op seek
to the current file position is performed. This appears to be
sufficient to "trick" Windows into allowing transitions between
read and writes without raising errors.
author | Gregory Szorc <gregory.szorc@gmail.com> |
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date | Sun, 27 Sep 2015 18:46:53 -0700 |
parents | b723f05ec49b |
children |
rev | line source |
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2953 | 1 # strutil.py - string utilities for Mercurial |
2 # | |
3 # Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com> | |
4 # | |
8225
46293a0c7e9f
updated license to be explicit about GPL version 2
Martin Geisler <mg@lazybytes.net>
parents:
8155
diff
changeset
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5 # This software may be used and distributed according to the terms of the |
10263 | 6 # GNU General Public License version 2 or any later version. |
2953 | 7 |
25979
b723f05ec49b
strutil: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents:
10263
diff
changeset
|
8 from __future__ import absolute_import |
b723f05ec49b
strutil: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents:
10263
diff
changeset
|
9 |
2953 | 10 def findall(haystack, needle, start=0, end=None): |
11 if end is None: | |
12 end = len(haystack) | |
13 if end < 0: | |
14 end += len(haystack) | |
15 if start < 0: | |
16 start += len(haystack) | |
17 while start < end: | |
18 c = haystack.find(needle, start, end) | |
19 if c == -1: | |
20 break | |
21 yield c | |
22 start = c + 1 | |
23 | |
24 def rfindall(haystack, needle, start=0, end=None): | |
25 if end is None: | |
26 end = len(haystack) | |
27 if end < 0: | |
28 end += len(haystack) | |
29 if start < 0: | |
30 start += len(haystack) | |
31 while end >= 0: | |
32 c = haystack.rfind(needle, start, end) | |
33 if c == -1: | |
34 break | |
35 yield c | |
36 end = c - 1 |