Watch the Internet Explorer registry keys so we can detect proxy settings changes faster.

Watch the Internet Explorer registry keys so we can detect proxy settings changes faster.

Previously we would poll on a background thread every 5 seconds (triggered by network activity) to check for changes. This meant there was a 5 second window during which new requests might still be using the old settings.

With this CL, the settings are noticed almost immediately and the continuous polling is de-emphasized.

(We still poll, but less often. This is a precaution since we are relying on implementation details of a winhttp function, and can't be sure it won't change in the future, or is even completely accurate right now).

BUG=52120
TEST=Open chrome://net-internals/#requests. Request some webpage. Now make changes to the Internet explorer proxy settinsg. You should see a PROXY_CONFIG_CHANGED event emitted immediately after saving each change in the dialog box.


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=56305

[eroman, 2010-08-14 01:57:55]

(Note I just made a small edit to polling_proxy_config_service.cc)

[rvargas (doing something else), 2010-08-16 19:04:12]

http://codereview.chromium.org/3161016/diff/11001/12001
File net/proxy/polling_proxy_config_service.cc (right):

http://codereview.chromium.org/3161016/diff/11001/12001#newcode79
net/proxy/polling_proxy_config_service.cc:79: if (num_poll_tasks_outstanding_ >
5) {
Did you consider just triggering a second check when the first one finishes if
there was a change notification while we were busy (and keeping only one
in-flight)?. We may end up receiving multiple notifications for a single "user"
change and discarding a few at the end may mean missing the "final" state (until
next poll).

If you considered that, I'm happy with the current version.

http://codereview.chromium.org/3161016/diff/11001/12001#newcode138
net/proxy/polling_proxy_config_service.cc:138: bool has_config_;
nit: do you mind moving this to be by the other bool member?

http://codereview.chromium.org/3161016/diff/11001/12003
File net/proxy/proxy_config_service_win.cc (right):

http://codereview.chromium.org/3161016/diff/11001/12003#newcode39
net/proxy/proxy_config_service_win.cc:39: struct ProxyConfigServiceWin::KeyEntry
{
Could you make this a class?.

http://codereview.chromium.org/3161016/diff/11001/12003#newcode102
net/proxy/proxy_config_service_win.cc:102:
L"SOFTWARE\\Policies\\Microsoft\\Windows\\CurrentVersion\\Internet Settings");
nit: break the string in two lines?

http://codereview.chromium.org/3161016/diff/11001/12004
File net/proxy/proxy_config_service_win.h (right):

http://codereview.chromium.org/3161016/diff/11001/12004#newcode32
net/proxy/proxy_config_service_win.h:32: // we also poll
WinHttpGetIEProxyConfigForCurrentUser() unconditionally every
Maybe saying that we keep doing regular polling is more precise.

[eroman, 2010-08-16 19:53:29]

http://codereview.chromium.org/3161016/diff/11001/12001
File net/proxy/polling_proxy_config_service.cc (right):

http://codereview.chromium.org/3161016/diff/11001/12001#newcode79
net/proxy/polling_proxy_config_service.cc:79: if (num_poll_tasks_outstanding_ >
5) {
On 2010/08/16 19:04:12, rvargas wrote:
> Did you consider just triggering a second check when the first one finishes if
> there was a change notification while we were busy (and keeping only one
> in-flight)?. We may end up receiving multiple notifications for a single
"user"
> change and discarding a few at the end may mean missing the "final" state
(until
> next poll).
> 
> If you considered that, I'm happy with the current version.

I was being lazy :)

You are right, we can do something better here and queue the updates so there is
only ever 1 in flight at a time.

I will update the change to do this, and let you know when it is ready for
review, thanks!

[eroman, 2010-08-16 20:33:18]

Thanks for the review!

http://codereview.chromium.org/3161016/diff/11001/12001
File net/proxy/polling_proxy_config_service.cc (right):

http://codereview.chromium.org/3161016/diff/11001/12001#newcode79
net/proxy/polling_proxy_config_service.cc:79: if (num_poll_tasks_outstanding_ >
5) {
On 2010/08/16 19:53:30, eroman wrote:
> On 2010/08/16 19:04:12, rvargas wrote:
> > Did you consider just triggering a second check when the first one finishes
if
> > there was a change notification while we were busy (and keeping only one
> > in-flight)?. We may end up receiving multiple notifications for a single
> "user"
> > change and discarding a few at the end may mean missing the "final" state
> (until
> > next poll).
> > 
> > If you considered that, I'm happy with the current version.
> 
> I was being lazy :)
> 
> You are right, we can do something better here and queue the updates so there
is
> only ever 1 in flight at a time.
> 
> I will update the change to do this, and let you know when it is ready for
> review, thanks!

Done. It should be cleaner now, and only ever have 1 task outstanding at a time.

http://codereview.chromium.org/3161016/diff/11001/12001#newcode138
net/proxy/polling_proxy_config_service.cc:138: bool has_config_;
On 2010/08/16 19:04:12, rvargas wrote:
> nit: do you mind moving this to be by the other bool member?

Done. I also moved all the bools to the end of the class so compiler might use
less padding.

http://codereview.chromium.org/3161016/diff/11001/12003
File net/proxy/proxy_config_service_win.cc (right):

http://codereview.chromium.org/3161016/diff/11001/12003#newcode39
net/proxy/proxy_config_service_win.cc:39: struct ProxyConfigServiceWin::KeyEntry
{
On 2010/08/16 19:04:12, rvargas wrote:
> Could you make this a class?.

Done.

http://codereview.chromium.org/3161016/diff/11001/12003#newcode102
net/proxy/proxy_config_service_win.cc:102:
L"SOFTWARE\\Policies\\Microsoft\\Windows\\CurrentVersion\\Internet Settings");
On 2010/08/16 19:04:12, rvargas wrote:
> nit: break the string in two lines?

Done.

http://codereview.chromium.org/3161016/diff/11001/12004
File net/proxy/proxy_config_service_win.h (right):

http://codereview.chromium.org/3161016/diff/11001/12004#newcode32
net/proxy/proxy_config_service_win.h:32: // we also poll
WinHttpGetIEProxyConfigForCurrentUser() unconditionally every
On 2010/08/16 19:04:12, rvargas wrote:
> Maybe saying that we keep doing regular polling is more precise.

I have reworked this comment, let me know if it is better now.

[rvargas (doing something else), 2010-08-16 23:07:08]

LGTM