We now acquire the DevMgr qutex when doing the newDASpecInd async
op. The qutex is held across an async sequence with potentially
a real hardware blocking bottleneck.
Since we have no choice but to access the sh_ptr<SenseApiLib> for
a lib before we can get its Qutex, we use this flag to ensure that
we can know whether the SenseApiLib data structure and its Qutex
are still valid when we enter -- i.e, we ensure that the SenseApiLib
object wasn't destroyed under our feet.
We now create the sh_ptr to the copy of a lockvoker object in its
own supplied register method. This enables us to retain type safety
when calling make_shared, by copying the most derived version of
the lockvoker object. Then we can pass in the LockerAndInvokerBase
to the rest of the call chain.
The dependency graph class enables us to perform analysis on the
qutex acquisition history data. By generating the graph and
detecting cycles in it, we can find true gridlocks.
We use this graph analysis code to implement the algorithmically
complete version of the gridlock detector.
We add the new Qutex acquisision history tracker that allows us
to dynamically detect qutex gridlocks. We've integrated it into
LockerAndInvoker::operator() in a preliminary way.
We also moved all of the trace*ForGridlockOn() methods into the
new QutexAcquisitionHistoryTracker singleton class. They're
more appropriately located there. They're still unimplemented
though.
We add the skeleton of a correct history tracer for gridlocks. The
previous history tracer made the incorrect assumption that we would
find the foreign sequence's currently desired LockSet inside of the
lockvoker that it has stored inside of Qutex::currOwner.
This ensures that the Lockvoker object we access from currOwner
remains valid past the lifetime of the Lockvoker object that
gets copied and invoked by boost::asio
hayodea