nim-libp2p/libp2p/muxers/mplex/mplex.nim

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## Nim-LibP2P
## Copyright (c) 2018 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.
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## TODO: I have to be carefull to clean channels up correctly,
## both by removing from the internal tables as well as
## releasing resource when the channel is completelly
## finished. This is complicated because half-closed
## streams makes closing channels non-deterministic.
##
## This still needs to be implemented properly - I'm leaving it
## here to not forget that this needs to be fixed ASAP.
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import tables, sequtils, options, strformat
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import chronos
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import coder, types, channel,
../../varint,
../../connection,
../../vbuffer,
../../protocols/protocol,
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../../stream/bufferstream,
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../../stream/lpstream,
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../muxer,
../../helpers/debug
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type
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Mplex* = ref object of Muxer
remote*: Table[uint, Channel]
local*: Table[uint, Channel]
currentId*: uint
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maxChannels*: uint
proc newMplexNoSuchChannel(id: uint, msgType: MessageType): ref MplexNoSuchChannel =
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result = newException(MplexNoSuchChannel, &"No such channel id {$id} and message {$msgType}")
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proc newMplexUnknownMsgError(): ref MplexUnknownMsgError =
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result = newException(MplexUnknownMsgError, "Unknown mplex message type")
proc getChannelList(m: Mplex, initiator: bool): var Table[uint, Channel] =
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if initiator:
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result = m.remote
else:
result = m.local
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proc newStreamInternal*(m: Mplex,
initiator: bool = true,
chanId: uint = 0,
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name: string = ""):
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Future[Channel] {.async, gcsafe.} =
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## create new channel/stream
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let id = if initiator: m.currentId.inc(); m.currentId else: chanId
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result = newChannel(id, m.connection, initiator, name)
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m.getChannelList(initiator)[id] = result
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method handle*(m: Mplex) {.async, gcsafe.} =
try:
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while not m.connection.closed:
let msgRes = await m.connection.readMsg()
if msgRes.isNone:
await sleepAsync(100.millis)
continue
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let (id, msgType, data) = msgRes.get()
let initiator = bool(ord(msgType) and 1)
var channel: Channel
if MessageType(msgType) != MessageType.New:
let channels = m.getChannelList(initiator)
if not channels.contains(id):
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debug &"handle: Channel with id {id} message type {msgType} not found"
continue
channel = channels[id]
case msgType:
of MessageType.New:
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let name = cast[string](data)
channel = await m.newStreamInternal(false, id, name)
debug &"handle: created channel with id {$id} and name {name}"
if not isNil(m.streamHandler):
let handlerFut = m.streamHandler(newConnection(channel))
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# TODO: don't use a closure?
# channel cleanup routine
proc cleanUpChan(udata: pointer) {.gcsafe.} =
if handlerFut.finished:
channel.close().addCallback(
proc(udata: pointer) =
# TODO: is waitFor() OK here?
channel.cleanUp()
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.addCallback(proc(udata: pointer)
= debug &"handle: cleaned up channel {$id}"))
handlerFut.addCallback(cleanUpChan)
continue
of MessageType.MsgIn, MessageType.MsgOut:
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debug &"handle: pushing data to channel {$id} type {msgType}"
await channel.pushTo(data)
of MessageType.CloseIn, MessageType.CloseOut:
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debug &"handle: closing channel {$id} type {msgType}"
await channel.closedByRemote()
m.getChannelList(initiator).del(id)
of MessageType.ResetIn, MessageType.ResetOut:
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debug &"handle: resetting channel {$id} type {msgType}"
await channel.resetByRemote()
break
else: raise newMplexUnknownMsgError()
finally:
await m.connection.close()
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proc newMplex*(conn: Connection,
maxChanns: uint = MaxChannels): Mplex =
new result
result.connection = conn
result.maxChannels = maxChanns
result.remote = initTable[uint, Channel]()
result.local = initTable[uint, Channel]()
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method newStream*(m: Mplex, name: string = ""): Future[Connection] {.async, gcsafe.} =
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let channel = await m.newStreamInternal()
await m.connection.writeMsg(channel.id, MessageType.New, name)
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result = newConnection(channel)
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method close*(m: Mplex) {.async, gcsafe.} =
await allFutures(@[allFutures(toSeq(m.remote.values).mapIt(it.close())),
allFutures(toSeq(m.local.values).mapIt(it.close()))])
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m.connection.reset()