If a value was already available in the local view the request is considered a cache hit.
If the materialized had to wait for a value, it is considered a cache miss.
Previous getFromView would call view.Result when the result may not have been returned
(because the index is updated past the minIndex. This would allocate a slice and sort it
for no reason, because the values would never be returned.
Fix this by re-ordering the operations in getFromView.
The test changes in this commit were an attempt to cover the case where
an update is received but the index does not exceed the minIndex.
Also rename it to readEntry now that it doesn't return the entire entry. Based on feedback
in PR review, the full entry is not used by the caller, and accessing the fields wouldn't be
safe outside the lock, so it is safer to return only the Materializer
Remove View.Result error return value, it was always nil, and seems like it will likely always remain nill
since it is simply reading a stored value.
Also replace some cache types with local types.
And only start expiration time when the last request ends. This makes tracking expiry simpler, and
ensures that no entry can be expired while there are active requests.
The materializer is often reset when an error is received. By resetting
the retryWaiter we effectively never wait. The retryWaiter should only
be reset when we get an event without error. This is done in
Materializer.updateView().
This call appears to only be necessary because reset() was called from
NewMaterializer.
This commit has the constructor set a default value for updateCh, and
removes both the call to reset() from New(), and the call to
notifyUpdateLocked() from reset().
This should ensure that we do not notify the Fetch() call before we have new
values to report.
Refactor of Materializer.Run
Use handlers to manage state in Materializer
Rename Materializer receiver
rename m.l to m.lock, and flip some conditionals to remove the negative.
Improve godoc, rename Deps, move resetErr, and pass err into notifyUpdate
Update for NewSnapshotToFollow events
Refactor to move context cancel out of Materializer
R.B. Boyer