wip: multistreamselect

libp2p/multistreamselect.nim

@@ -7,5 +7,70 @@
 ## This file may not be copied, modified, or distributed except according to
 ## those terms.
 
-type MultisteamSelect = ref object of RootObj
+import sequtils
+import chronos
+import connection, varint, vbuffer
 
+const Codec* = "/multistream/1.0.0"
+const Na = "na\n"
+const Ls = "ls\n"
+
+type 
+  MultisteamSelectException = object of CatchableError
+
+  Handler* = proc (conn: Connection, proto: string): Future[void]
+  Matcher* = proc (proto: string): bool
+
+  HandlerHolder* = object
+    proto: string
+    handler: Handler
+    match: Matcher
+
+  MultisteamSelect* = ref object of RootObj
+    handlers*: seq[HandlerHolder]
+    codec*: seq[byte]
+    na*: seq[byte]
+    ls*: seq[byte]
+
+proc lp*(data: string): seq[byte] =
+  var buf = initVBuffer(newSeq[byte](256))
+  buf.writeSeq(data)
+  var lpData = newSeq[byte](buf.length)
+  if buf.readSeq(lpData) < 0:
+    raise newException(MultisteamSelectException, "Error: failed to lenght prefix")
+  result = lpData
+
+proc newMultistream*(): MultisteamSelect =
+  new result
+  result.codec = lp(Codec & "\n")
+  result.na = lp(Na)
+  result.ls = lp(Ls)
+
+proc select*(m: MultisteamSelect, conn: Connection, proto: string): Future[bool] {.async.} = 
+  ## select a remote protocol
+  await conn.write(m.codec)
+  await conn.write(lp(proto)) # select proto
+
+  let ms = await conn.readLine(0, "\n")
+  if ms != Codec: 
+    raise newException(MultisteamSelectException, "Error: invalid multistream codec" & $ms)
+
+  let remote = await conn.readLine(0, "\n")
+  result = remote == proto
+
+proc ls*(m: MultisteamSelect): seq[string] {.async.} = 
+  ## list all remote protocol strings
+  discard
+
+proc handle*(m: MultisteamSelect, conn: Connection) {.async.} =
+  ## handle requests on connection
+  discard
+
+proc addHandle*(m: MultisteamSelect, 
+                proto: string, 
+                handler: Handler, 
+                matcher: Matcher = nil) = 
+  ## register a handler for the protocol
+  m.handlers.add(HandlerHolder(proto: proto, 
+                               handler: handler, 
+                               match: matcher))