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

119 lines
4.2 KiB
Nim

## 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.
## 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.
import tables, sequtils, strformat, options
import chronos
import coder, types, channel,
../../varint,
../../connection,
../../vbuffer,
../../protocols/protocol,
../../stream/bufferstream,
../../stream/lpstream,
../muxer
type
Mplex* = ref object of Muxer
remote*: Table[int, Channel]
local*: Table[int, Channel]
currentId*: int
maxChannels*: uint
proc newMplexNoSuchChannel(id: int, msgType: MessageType): ref MplexNoSuchChannel =
result = newException(MplexNoSuchChannel, &"No such channel id {$id} and message {$msgType}")
proc newMplexUnknownMsgError(): ref MplexUnknownMsgError =
result = newException(MplexUnknownMsgError, "Unknown mplex message type")
proc getChannelList(m: Mplex, initiator: bool): var Table[int, Channel] =
if initiator:
result = m.remote
else:
result = m.local
proc newStreamInternal*(m: Mplex,
initiator: bool = true,
chanId: int,
name: string = ""):
Future[Channel] {.async, gcsafe.} =
## create new channel/stream
let id = if initiator: m.currentId.inc(); m.currentId else: chanId
result = newChannel(id, m.connection, initiator, name)
m.getChannelList(initiator)[id] = result
proc newStreamInternal*(m: Mplex): Future[Channel] {.gcsafe.} =
result = m.newStreamInternal(true, 0)
method handle*(m: Mplex): Future[void] {.async, gcsafe.} =
try:
while not m.connection.closed:
let (id, msgType) = await m.connection.readHeader()
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.int):
raise newMplexNoSuchChannel(id.int, msgType)
channel = channels[id.int]
case msgType:
of MessageType.New:
var name: seq[byte]
try:
name = await m.connection.readLp()
except LPStreamIncompleteError as exc:
echo exc.msg
except Exception as exc:
echo exc.msg
raise
let channel = await m.newStreamInternal(false, id.int, cast[string](name))
if not isNil(m.streamHandler):
channel.handlerFuture = m.streamHandler(newConnection(channel))
of MessageType.MsgIn, MessageType.MsgOut:
let msg = await m.connection.readLp()
await channel.pushTo(msg)
of MessageType.CloseIn, MessageType.CloseOut:
await channel.closedByRemote()
m.getChannelList(initiator).del(id.int)
of MessageType.ResetIn, MessageType.ResetOut:
await channel.resetByRemote()
else: raise newMplexUnknownMsgError()
finally:
await m.connection.close()
proc newMplex*(conn: Connection,
maxChanns: uint = MaxChannels): Mplex =
new result
result.connection = conn
result.maxChannels = maxChanns
result.remote = initTable[int, Channel]()
result.local = initTable[int, Channel]()
method newStream*(m: Mplex, name: string = ""): Future[Connection] {.async, gcsafe.} =
let channel = await m.newStreamInternal()
await m.connection.writeHeader(channel.id, MessageType.New, len(name))
if name.len > 0:
await m.connection.write(name)
result = newConnection(channel)
method close*(m: Mplex) {.async, gcsafe.} =
await allFutures(@[allFutures(toSeq(m.remote.values).mapIt(it.close())),
allFutures(toSeq(m.local.values).mapIt(it.close()))])
m.connection.reset()