CancellableTimer tests were in a timer_test package but lived within the
tcpip directory. This caused issues with go tools.
PiperOrigin-RevId: 289166345
* Rename syncutil to sync.
* Add aliases to sync types.
* Replace existing usage of standard library sync package.
This will make it easier to swap out synchronization primitives. For example,
this will allow us to use primitives from github.com/sasha-s/go-deadlock to
check for lock ordering violations.
Updates #1472
PiperOrigin-RevId: 289033387
Add a new CancellableTimer type to encapsulate the work of safely stopping
timers when it fires at the same time some "related work" is being handled. The
term "related work" is some work that needs to be done while having obtained
some common lock (L).
Example: Say we have an invalidation timer that may be extended or cancelled by
some event. Creating a normal timer and simply cancelling may not be sufficient
as the timer may have already fired when the event handler attemps to cancel it.
Even if the timer and event handler obtains L before doing work, once the event
handler releases L, the timer will eventually obtain L and do some unwanted
work.
To prevent the timer from doing unwanted work, it checks if it should early
return instead of doing the normal work after obtaining L. When stopping the
timer callers must have L locked so the timer can be safely informed that it
should early return.
Test: Tests that CancellableTimer fires and resets properly. Test to make sure
the timer fn is not called after being stopped within the lock L.
PiperOrigin-RevId: 288806984
Nothing reads them and they can simply get stale.
Generated with:
$ sed -i "s/licenses(\(.*\)).*/licenses(\1)/" **/BUILD
PiperOrigin-RevId: 231818945
Change-Id: Ibc3f9838546b7e94f13f217060d31f4ada9d4bf0
Netstack needs to be portable, so this seems to be preferable to using raw
system calls.
PiperOrigin-RevId: 212917409
Change-Id: I7b2073e7db4b4bf75300717ca23aea4c15be944c
We have been unnecessarily creating too many savable types implicitly.
PiperOrigin-RevId: 206334201
Change-Id: Idc5a3a14bfb7ee125c4f2bb2b1c53164e46f29a8