tree 52ba3bb2acd4ddf4d1633f420de6c64040a23dc8
parent a4d9ee474daa309cff360c214fcdba1a4f5a0d53
author Tilak Sharma <tilaks@google.com> 1403313393 -0700
committer Tilak Sharma <tilaks@google.com> 1403315250 -0700

veyron/runtimes/google/lib/follow: Fix initialization race in the follow watcher.

Sometimes, a watcher would not detect modifications to the file immediately
after the watcher was created.
This caused a race condition in Read:
1) Routine #1 creates a reader, which in turn creates a watcher.
2) Routine #1 calls reader.Read(). The Read doesn't see enough bytes, so
   Routine #1 awaits an event from watcher.
3) Routine #2 writes to the file.
4) The watcher's watch routine is initialized. However, it missed the write,
   and does not send an event.
As a result, Read hangs.

The watcher now waits until the watch routine is initialized before it returns.

Change-Id: Idd03b7d6a7cf7560315a8a6661c60f55dd7a06a1