Introduce a middleware called `NetworkServiceProvider` which the
`ChainSync` can use to communicate with `NetworkService`. `ChainSync` is
given a `NetworkServiceHandle` which it uses to call `NetworkServiceProvider`
which then dispatches the calls to `NetworkService` on behalf of `ChainSync`.
This change will allow `ChainSync` to disconnect and report peers and
in the future it'll be possible to send requests and notifications
through the `NetworkServiceProvider`.
`NetworkServiceProvider` is needed only until the `ChainSync` object
has been removed from `Protocol`. After that, a normal `NetworkService`
handle can be passed onto `ChainSync` and these changes can be
deprecated.
Co-authored-by: parity-processbot <>
* Introduce `ChainSyncInterface`
`ChainSyncInterface` provides an asynchronous interface for other
subsystems to submit calls to `ChainSync`. This allows `NetworkService`
to delegate calls to `ChainSync` while still providing the same API
for other subsystems (for now). This makes it possible to move the
syncing code in piecemeal fashion out of `protocol.rs` as the calls
are just forwarded to `ChainSync`.
* Apply review comments
* Fix tests
Aaro Altonen