As part of reusing the block utility object, asynchronous say block
functions cannot use the utility in a promise or timeout asynchronous
handle. Store the needed target reference so utility is not needed
later.
blockUtility as an object literal inside execute creates 11 objects,
one for the object, and 10 for the function closures. As a separate
object and allocated once, setting its sequencer and thread members,
block functions can share the same util object. Extract blockUtility to
cut down on allocations.
`handleReport` inside `src/engine/execute.js`'s `execute` method needs
to allocate a closure to be able to refer to the higher scoped
variables. `execute` is called frequently that this has a noticable
impact on memory allocation and later collection. Extract handleReport
and add arguments to prevent the allocation.
Testing with implicitly casted `value` and `value.then` is deoptimizing
isPromise, which deoptimizes execute. In this case deoptimizing means
that the JavaScript VM cannot compile the functions into a form that
can be run faster.
Remove indexOf tests for thread existence in doneThreads. Maintain a
list of null and thread objects mirroring the index position of threads
that are done in runtime.threads. Filter out null values after
filtering out done threads from runtime.threads.
This has a small side effect that threads that normally became DONE and
were added to doneThreads before being removed or restarted will not be
in doneThreads in this version. Restarted threads (_restartThread) do
not appear in this version but new copies will be in Runtime
this.threads supporting glow and monitor updates. Removed threads
(_removeThread) do not appear in this version if they are removed after
they were seen as DONE by the prior version. Threads removed before
they are seen as DONE do not appear in doneThreads in the prior or this
version.
Threads that are removed before normally becoming DONE do not appear in
doneThreads in either case. Threads that are restarted before the loop
checks if the thread is done do not appear in doneThreads in either
case.
