Mercurial > hg
view mercurial/py3kcompat.py @ 30446:b324b4e431e5
posix: give checkexec a fast path; keep the check files and test read only
Before, Mercurial would create a new temporary file every time, stat it, change
its exec mode, stat it again, and delete it. Most of this dance was done to
handle the rare and not-so-essential case of VFAT mounts on unix. The cost of
that was paid by the much more common and important case of using normal file
systems.
Instead, try to create and preserve .hg/cache/checkisexec and
.hg/cache/checknoexec with and without exec flag set. If the files exist and
have correct exec flags set, we can conclude that that file system supports the
exec flag. Best case, the whole exec check can thus be done with two stat
calls. Worst case, we delete the wrong files and check as usual. That will be
because temporary loss of exec bit or on file systems without support for the
exec bit. In that case we check as we did before, with the additional overhead
of one extra stat call.
It is possible that this different test algorithm in some cases on odd file
systems will give different behaviour. Again, I think it will be rare and
special cases and I think it is worth the risk.
test-clone.t happens to show the situation where checkisexec is left behind
from the old style check, while checknoexec only will be created next time a
exec check will be performed.
author | Mads Kiilerich <madski@unity3d.com> |
---|---|
date | Wed, 14 Jan 2015 01:15:26 +0100 |
parents | 5bfd01a3c2a9 |
children |
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# py3kcompat.py - compatibility definitions for running hg in py3k # # Copyright 2010 Renato Cunha <renatoc@gmail.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import builtins import numbers Number = numbers.Number def bytesformatter(format, args): '''Custom implementation of a formatter for bytestrings. This function currently relies on the string formatter to do the formatting and always returns bytes objects. >>> bytesformatter(20, 10) 0 >>> bytesformatter('unicode %s, %s!', ('string', 'foo')) b'unicode string, foo!' >>> bytesformatter(b'test %s', 'me') b'test me' >>> bytesformatter('test %s', 'me') b'test me' >>> bytesformatter(b'test %s', b'me') b'test me' >>> bytesformatter('test %s', b'me') b'test me' >>> bytesformatter('test %d: %s', (1, b'result')) b'test 1: result' ''' # The current implementation just converts from bytes to unicode, do # what's needed and then convert the results back to bytes. # Another alternative is to use the Python C API implementation. if isinstance(format, Number): # If the fixer erroneously passes a number remainder operation to # bytesformatter, we just return the correct operation return format % args if isinstance(format, bytes): format = format.decode('utf-8', 'surrogateescape') if isinstance(args, bytes): args = args.decode('utf-8', 'surrogateescape') if isinstance(args, tuple): newargs = [] for arg in args: if isinstance(arg, bytes): arg = arg.decode('utf-8', 'surrogateescape') newargs.append(arg) args = tuple(newargs) ret = format % args return ret.encode('utf-8', 'surrogateescape') builtins.bytesformatter = bytesformatter origord = builtins.ord def fakeord(char): if isinstance(char, int): return char return origord(char) builtins.ord = fakeord if __name__ == '__main__': import doctest doctest.testmod()