nim-libp2p/libp2p/protocols/protocol.nim

109 lines
3.1 KiB
Nim

# Nim-LibP2P
# Copyright (c) 2023-2024 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
# * MIT license ([LICENSE-MIT](LICENSE-MIT))
# at your option.
# This file may not be copied, modified, or distributed except according to
# those terms.
{.push raises: [].}
import chronos, stew/results
import ../stream/connection
export results
const
DefaultMaxIncomingStreams* = 10
type
LPProtoHandler* = proc (
conn: Connection,
proto: string): Future[void] {.async.}
LPProtocol* = ref object of RootObj
codecs*: seq[string]
handlerImpl: LPProtoHandler ## invoked by the protocol negotiator
started*: bool
maxIncomingStreams: Opt[int]
method init*(p: LPProtocol) {.base, gcsafe.} = discard
method start*(
p: LPProtocol) {.async: (raises: [CancelledError], raw: true), base.} =
let fut = newFuture[void]()
fut.complete()
p.started = true
fut
method stop*(p: LPProtocol) {.async: (raises: [], raw: true), base.} =
let fut = newFuture[void]()
fut.complete()
p.started = false
fut
proc maxIncomingStreams*(p: LPProtocol): int =
p.maxIncomingStreams.get(DefaultMaxIncomingStreams)
proc `maxIncomingStreams=`*(p: LPProtocol, val: int) =
p.maxIncomingStreams = Opt.some(val)
func codec*(p: LPProtocol): string =
doAssert(p.codecs.len > 0, "Codecs sequence was empty!")
p.codecs[0]
func `codec=`*(p: LPProtocol, codec: string) =
# always insert as first codec
# if we use this abstraction
p.codecs.insert(codec, 0)
template `handler`*(p: LPProtocol): LPProtoHandler =
p.handlerImpl
template `handler`*(
p: LPProtocol, conn: Connection, proto: string): Future[void] =
p.handlerImpl(conn, proto)
func `handler=`*(p: LPProtocol, handler: LPProtoHandler) =
p.handlerImpl = handler
# Callbacks that are annotated with `{.async: (raises).}` explicitly
# document the types of errors that they may raise, but are not compatible
# with `LPProtoHandler` and need to use a custom `proc` type.
# They are internally wrapped into a `LPProtoHandler`, but still allow the
# compiler to check that their `{.async: (raises).}` annotation is correct.
# https://github.com/nim-lang/Nim/issues/23432
func `handler=`*[E](
p: LPProtocol,
handler: proc (
conn: Connection,
proto: string): InternalRaisesFuture[void, E]) =
proc wrap(conn: Connection, proto: string): Future[void] {.async.} =
await handler(conn, proto)
p.handlerImpl = wrap
proc new*(
T: type LPProtocol,
codecs: seq[string],
handler: LPProtoHandler,
maxIncomingStreams: Opt[int] | int = Opt.none(int)): T =
T(
codecs: codecs,
handlerImpl: handler,
maxIncomingStreams:
when maxIncomingStreams is int: Opt.some(maxIncomingStreams)
else: maxIncomingStreams
)
proc new*[E](
T: type LPProtocol,
codecs: seq[string],
handler: proc (
conn: Connection,
proto: string): InternalRaisesFuture[void, E],
maxIncomingStreams: Opt[int] | int = Opt.none(int)): T =
proc wrap(conn: Connection, proto: string): Future[void] {.async.} =
await handler(conn, proto)
T.new(codec, wrap, maxIncomingStreams)