A goroutine is used to manage the lifetime of subscriptions managed by
resubscriptions. When the subscription ends with no error, the resub
goroutine ends as well. However, the resub goroutine needs to live
long enough to read from the unsub channel. Otheriwse, an Unsubscribe
call deadlocks when writing to the unsub channel.
This is fixed by adding a buffer to the unsub channel.
Co-authored-by: Inphi <mlaw2501@gmail.com>
This adds a way to get the error of the failing subscription
for logging/debugging purposes.
Co-authored-by: Łukasz Zimnoch <lukaszzimnoch1994@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
The name of a method’s receiver should be a reflection of its identity;
often a one or two letter abbreviation of its type suffices (such as
“c” or “cl” for “Client”). Don’t use generic names such as “me”, “this”
or “self”, identifiers typical of object-oriented languages that place
more emphasis on methods as opposed to functions. The name need not be
as descriptive as that of a method argument, as its role is obvious and
serves no documentary purpose. It can be very short as it will appear
on almost every line of every method of the type; familiarity admits
brevity. Be consistent, too: if you call the receiver “c” in one method,
don’t call it “cl” in another.
Feed keeps active subscription channels in a slice called 'f.sendCases'.
The Send method tracks the active cases in a local variable 'cases'
whose value is f.sendCases initially. 'cases' shrinks to a shorter
prefix of f.sendCases every time a send succeeds, moving the successful
case out of range of the active case list.
This can be confusing because the two slices share a backing array. Add
more comments to document what is going on. Also add a test for removing
a case that is in 'f.sentCases' but not 'cases'.
Feed keeps active subscription channels in a slice called 'f.sendCases'.
The Send method tracks the active cases in a local variable 'cases'
whose value is f.sendCases initially. 'cases' shrinks to a shorter
prefix of f.sendCases every time a send succeeds, moving the successful
case out of range of the active case list.
This can be confusing because the two slices share a backing array. Add
more comments to document what is going on. Also add a test for removing
a case that is in 'f.sentCases' but not 'cases'.
There is no need to depend on the old context package now that the
minimum Go version is 1.7. The move to "context" eliminates our weird
vendoring setup. Some vendored code still uses golang.org/x/net/context
and it is now vendored in the normal way.
This change triggered new vet checks around context.WithTimeout which
didn't fire with golang.org/x/net/context.
event: address Feed review issues
event: clarify role of NewSubscription function
event: more Feed review fixes
* take sendLock after dropping f.mu
* add constant for number of special cases
event: fix subscribing/unsubscribing while Send is blocked
This commit introduces a new Subscription type, which is synonymous with
ethereum.Subscription. It also adds a couple of utilities that make
working with Subscriptions easier. The mot complex utility is Feed, a
synchronisation device that implements broadcast subscriptions. Feed is
slightly faster than TypeMux and will replace uses of TypeMux across the
go-ethereum codebase in the future.
The Subscription type is gone, all uses are replaced by
*TypeMuxSubscription. This change is prep-work for the
introduction of the new Subscription type in a later commit.
gorename -from '"github.com/ethereum/go-ethereum/event"::Event' -to TypeMuxEvent
gorename -from '"github.com/ethereum/go-ethereum/event"::muxsub' -to TypeMuxSubscription
gofmt -w -r 'Subscription -> *TypeMuxSubscription' ./event/*.go
find . -name '*.go' -and -not -regex '\./vendor/.*' \| xargs gofmt -w -r 'event.Subscription -> *event.TypeMuxSubscription'
This fixes an issue where the following would lead to a panic due to a
channel being closed twice:
* Start mux
* Stop mux
* Sub to mux
* Unsub
This is fixed by setting the subscriptions status to closed resulting in
the Unsubscribe to ignore the request when called.
Moved the filtering system from `event` to `eth/filters` package and
removed the `core.Filter` object. The `filters.Filter` object now
requires a `common.Database` rather than a `eth.Backend` and invokes the
`core.GetBlockByX` directly rather than thru a "manager".
