The two active users of DeadlineTimer, NetworkOPs and Application,
now use asio::steady_timers rather than DeadlineTimer.
DeadlineTimer is removed since it is no longer used.
To assure that all in-flight closures on timers are done before
Stoppables call stopped(), the JobCounter is made more generic.
It's now a ClosureCounter. The ClosureCounter is currently used
to count closures in flight for the JobQueue, NetworkOPs, and the
Application.
If the JobQueue is used during shutdown then those Jobs may access
Stoppables after they have already stopped. This violates the
preconditions of Stoppables and may lead to undefined behavior.
The solution taken here is to reference count all Jobs in the
JobQueue. At stop time all Jobs already in the JobQueue are
allowed to run to completion, but no further Jobs are allowed
into the JobQueue.
If a Job is rejected from the JobQueue (because we are stopping),
then JobQueue::addJob() returns false, so the caller can make any
necessary adjustments.
A new JobCounter class is introduced. The JobCounter keeps
a reference count of Jobs in flight to the JobQueue. When
NetworkOPs needs to stop, in addition to other work, it calls
JobCounter::join(), which waits until all Jobs in flight
have been destroyed before returning. This ensures that all
NetworkOPs Jobs are completed before NetworkOPs declares
itself stopped().
Also, once a JobCounter is join()ed, it refuses to produce
more counted Jobs for the JobQueue. So, once all old Jobs
in flight are done, then NetworkOPs will add no additional
Jobs to the JobQueue.
Other classes besides NetworkOPs should also be able to use
JobCounter. NetworkOPs is a first test case.
Also unneeded #includes were removed from files touched for
other reasons.
All uses of beast::Thread were previously removed from the code
base, so beast::Thread is removed. One piece of beast::Thread
needed to be preserved: the ability to set the current thread's
name. So there's now a beast::CurrentThreadName that allows the
current thread's name to be set and returned.
Thread naming is also cleaned up a bit. ThreadName.h and .cpp
are removed since beast::CurrentThreadName does a better job.
ThreadEntry is also removed, but its terminateHandler() is
preserved in TerminateHandler.cpp. The revised terminateHandler()
uses beast::CurrentThreadName to recover the name of the running
thread.
Finally, the NO_LOG_UNHANDLED_EXCEPTIONS #define is removed since
it was discovered that the MacOS debugger preserves the stack
of the original throw even if the terminateHandler() rethrows.
