Mercurial > hg
view tests/test-atomictempfile.py @ 29201:a109bf7e0dc2
util: make atomictempfile avoid ambiguity of file stat if needed
Ambiguity check is executed at close(), only if:
- atomictempfile is created with checkambig=True, and
- target file exists before renaming
This restriction avoids performance decrement by needless examination
of file stat (for example, filelog doesn't need exact cache
validation, even though it uses atomictempfile to write changes out).
See description of filestat class for detail about why the logic in
this patch works as expected.
This patch is a part of preparation for "Exact Cache Validation Plan":
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
author | FUJIWARA Katsunori <foozy@lares.dti.ne.jp> |
---|---|
date | Thu, 19 May 2016 00:20:38 +0900 |
parents | 3bea82dd4c4e |
children | 1acf654f0985 |
line wrap: on
line source
from __future__ import absolute_import import glob import os import unittest from mercurial import ( util, ) atomictempfile = util.atomictempfile class testatomictempfile(unittest.TestCase): def test1_simple(self): if os.path.exists('foo'): os.remove('foo') file = atomictempfile('foo') (dir, basename) = os.path.split(file._tempname) self.assertFalse(os.path.isfile('foo')) self.assertTrue(basename in glob.glob('.foo-*')) file.write(b'argh\n') file.close() self.assertTrue(os.path.isfile('foo')) self.assertTrue(basename not in glob.glob('.foo-*')) # discard() removes the temp file without making the write permanent def test2_discard(self): if os.path.exists('foo'): os.remove('foo') file = atomictempfile('foo') (dir, basename) = os.path.split(file._tempname) file.write(b'yo\n') file.discard() self.assertFalse(os.path.isfile('foo')) self.assertTrue(basename not in os.listdir('.')) # if a programmer screws up and passes bad args to atomictempfile, they # get a plain ordinary TypeError, not infinite recursion def test3_oops(self): self.assertRaises(TypeError, atomictempfile) # checkambig=True avoids ambiguity of timestamp def test4_checkambig(self): def atomicwrite(checkambig): f = atomictempfile('foo', checkambig=checkambig) f.write('FOO') f.close() # try some times, because reproduction of ambiguity depends on # "filesystem time" for i in xrange(5): atomicwrite(False) oldstat = os.stat('foo') if oldstat.st_ctime != oldstat.st_mtime: # subsequent changing never causes ambiguity continue repetition = 3 # repeat atomic write with checkambig=True, to examine # whether st_mtime is advanced multiple times as expecetd for j in xrange(repetition): atomicwrite(True) newstat = os.stat('foo') if oldstat.st_ctime != newstat.st_ctime: # timestamp ambiguity was naturally avoided while repetition continue # st_mtime should be advanced "repetition" times, because # all atomicwrite() occured at same time (in sec) self.assertTrue(newstat.st_mtime == ((oldstat.st_mtime + repetition) & 0x7fffffff)) # no more examination is needed, if assumption above is true break else: # This platform seems too slow to examine anti-ambiguity # of file timestamp (or test happened to be executed at # bad timing). Exit silently in this case, because running # on other faster platforms can detect problems pass if __name__ == '__main__': import silenttestrunner silenttestrunner.main(__name__)