Docserver: Further refactoring to the new GithubFileSystem to make it update

Docserver: Further refactoring to the new GithubFileSystem to make it update
content properly. Change it to behave the same way on Read and Refresh (in fact
Refresh becomes just an alias for Read) to address the bug where having
concurrent Read and Refresh futures overwrite each other.

BUG=318878
R=yoz@chromium.org
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=236877

[not at google - send to devlin, 2013-11-22 01:36:13]

Hey Yoyo, sorry about the dense-ness of this change. I've tried to comment it
well.

Once again I can't really test this until it goes live - it's hard to simulate a
realistic environment using start_dev_server - but I've added unit tests, and
sticking logging around the place make it appear that it's working properly.

[Yoyo Zhou, 2013-11-22 22:52:02]

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
File chrome/common/extensions/docs/server2/new_github_file_system.py (right):

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
chrome/common/extensions/docs/server2/new_github_file_system.py:138:
'''Initializes |self._repo_zip| if hasn't already been (i.e. if
nit: if it

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
chrome/common/extensions/docs/server2/new_github_file_system.py:185:
self._transient_stat_cache.Set(repo_key, version)
We should do away with this and replace it with a 'needs_refresh' bit (as we
discussed in person).

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
chrome/common/extensions/docs/server2/new_github_file_system.py:267: repo_zip =
self._repo_zip.Get()  # if only Stat returned a Future...
Is this a TODO?

[not at google - send to devlin, 2013-11-22 23:01:57]

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
File chrome/common/extensions/docs/server2/new_github_file_system.py (right):

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
chrome/common/extensions/docs/server2/new_github_file_system.py:138:
'''Initializes |self._repo_zip| if hasn't already been (i.e. if
On 2013/11/22 22:52:02, Yoyo Zhou wrote:
> nit: if it

Done.

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
chrome/common/extensions/docs/server2/new_github_file_system.py:185:
self._transient_stat_cache.Set(repo_key, version)
On 2013/11/22 22:52:02, Yoyo Zhou wrote:
> We should do away with this and replace it with a 'needs_refresh' bit (as we
> discussed in person).

Done, though I called it "up to date" since that's more compatible with the
false-by-default behaviour of these caches.

https://chromiumcodereview.appspot.com/82433002/diff/1/chrome/common/extensio...
chrome/common/extensions/docs/server2/new_github_file_system.py:267: repo_zip =
self._repo_zip.Get()  # if only Stat returned a Future...
On 2013/11/22 22:52:02, Yoyo Zhou wrote:
> Is this a TODO?

Internal dialogue. Deleted.

[Yoyo Zhou, 2013-11-22 23:22:55]

LGTM, this is more understandable.

[commit-bot: I haz the power, 2013-11-22 23:51:23]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/kalman@chromium.org/82433002/130001

[commit-bot: I haz the power, 2013-11-22 23:53:50]

Change committed as 236877