tests/svn-safe-append.py
author Adrian Buehlmann <adrian@cadifra.com>
Wed, 18 May 2011 09:12:27 +0200
changeset 14413 5ef18e28df19
parent 6439 c1b47c0fd2b6
child 29195 bdba6a2015d0
permissions -rwxr-xr-x
pure: provide more correct implementation of posixfile for Windows requires ctypes Why is posixfile a class? Because the implementation needs to use the Python library call os.fdopen [1], which sets the 'name' attribute on the Python file object it creates to the mostly meaningless string '<fdopen>', since file descriptors don't have a name. But users of posixfile depend on the name attribute [2] being set to a proper value, like Python's built-in 'open' function sets it on file objects. Python file's name attribute is read-only, so we can't just assign to it after the file object has alrady been created. To solve this problem, we save the name of the file on a wrapper object, and delegate the file function calls to the wrapped (private) file object using __getattr__. [1] http://docs.python.org/library/os.html#os.fdopen [2] http://docs.python.org/library/stdtypes.html#file.name

#!/usr/bin/env python

__doc__ = """Same as `echo a >> b`, but ensures a changed mtime of b.
Without this svn will not detect workspace changes."""

import sys, os

text = sys.argv[1]
fname = sys.argv[2]

f = open(fname, "ab")
try:
    before = os.fstat(f.fileno()).st_mtime
    f.write(text)
    f.write("\n")
finally:
    f.close()
inc = 1
now = os.stat(fname).st_mtime
while now == before:
    t = now + inc
    inc += 1
    os.utime(fname, (t, t))
    now = os.stat(fname).st_mtime