##// END OF EJS Templates
windows: insert file positioning call between reads and writes...
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.

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fancyopts.py
127 lines | 3.5 KiB | text/x-python | PythonLexer
# fancyopts.py - better command line parsing
#
# Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others
#
# 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 getopt
from .i18n import _
from . import util
def gnugetopt(args, options, longoptions):
"""Parse options mostly like getopt.gnu_getopt.
This is different from getopt.gnu_getopt in that an argument of - will
become an argument of - instead of vanishing completely.
"""
extraargs = []
if '--' in args:
stopindex = args.index('--')
extraargs = args[stopindex + 1:]
args = args[:stopindex]
opts, parseargs = getopt.getopt(args, options, longoptions)
args = []
while parseargs:
arg = parseargs.pop(0)
if arg and arg[0] == '-' and len(arg) > 1:
parseargs.insert(0, arg)
topts, newparseargs = getopt.getopt(parseargs, options, longoptions)
opts = opts + topts
parseargs = newparseargs
else:
args.append(arg)
args.extend(extraargs)
return opts, args
def fancyopts(args, options, state, gnu=False):
"""
read args, parse options, and store options in state
each option is a tuple of:
short option or ''
long option
default value
description
option value label(optional)
option types include:
boolean or none - option sets variable in state to true
string - parameter string is stored in state
list - parameter string is added to a list
integer - parameter strings is stored as int
function - call function with parameter
non-option args are returned
"""
namelist = []
shortlist = ''
argmap = {}
defmap = {}
for option in options:
if len(option) == 5:
short, name, default, comment, dummy = option
else:
short, name, default, comment = option
# convert opts to getopt format
oname = name
name = name.replace('-', '_')
argmap['-' + short] = argmap['--' + oname] = name
defmap[name] = default
# copy defaults to state
if isinstance(default, list):
state[name] = default[:]
elif callable(default):
state[name] = None
else:
state[name] = default
# does it take a parameter?
if not (default is None or default is True or default is False):
if short:
short += ':'
if oname:
oname += '='
if short:
shortlist += short
if name:
namelist.append(oname)
# parse arguments
if gnu:
parse = gnugetopt
else:
parse = getopt.getopt
opts, args = parse(args, shortlist, namelist)
# transfer result to state
for opt, val in opts:
name = argmap[opt]
obj = defmap[name]
t = type(obj)
if callable(obj):
state[name] = defmap[name](val)
elif t is type(1):
try:
state[name] = int(val)
except ValueError:
raise util.Abort(_('invalid value %r for option %s, '
'expected int') % (val, opt))
elif t is type(''):
state[name] = val
elif t is type([]):
state[name].append(val)
elif t is type(None) or t is type(False):
state[name] = True
# return unparsed args
return args