This PR adds a new type event.FeedOf[T], which is like event.Feed but parameterized
over the channel element type. Performance is unchanged, and it still uses reflect. But
unlike Feed, the generic version doesn't need to type-check interface{} arguments.
All panic cases are gone from the API.
The leaks were mostly in unit tests, and could all be resolved by
adding suitably-sized channel buffers or by restructuring the test
to not send on a channel after an error has occurred.
There is an unavoidable goroutine leak in Console.Interactive: when
we receive a signal, the line reader cannot be unblocked and will get
stuck. This leak is now documented and I've tried to make it slightly
less bad by adding a one-element buffer to the output channels of
the line-reading loop. Should the reader eventually awake from its
blocked state (i.e. when stdin is closed), at least it won't get stuck
trying to send to the interpreter loop which has quit long ago.
Co-authored-by: Felix Lange <fjl@twurst.com>
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".
