tree 707fa787557ebc03206903d12f8520b430eaf172
parent 5d47a4b6e7ef1aa02072957ecc7cac78b7294632
author Allen Li <ayatane@google.com> 1503086523 -0700
committer chrome-bot <chrome-bot@chromium.org> 1505203924 -0700

Fix locking

Remove race conditions that cause referenced bug.

The test script does not reproduce said bug, but it provides some
psychological comfort at least that the locking code works no worse
than previously.

See the docstring in the flock.py for more rationale on design
choices.

BUG=chromium:756001
TEST=test script
TEST=unit tests
TEST=Run turtle script

Change-Id: I74070ca9f4fa8118233a8ebd91880521cb47d2a8
Reviewed-on: https://chromium-review.googlesource.com/622246
Commit-Ready: Allen Li <ayatane@chromium.org>
Tested-by: Allen Li <ayatane@chromium.org>
Reviewed-by: Allen Li <ayatane@chromium.org>