wip: multistream select rework

libp2p/multistream.nim

@@ -7,8 +7,8 @@
 ## This file may not be copied, modified, or distributed except according to
 ## those terms.
 
-import strutils
+import strutils, sequtils
-import chronos, chronicles
+import chronos, chronicles, stew/byteutils
 import vbuffer,
        protocols/protocol,
        streams/[connection,
@@ -37,9 +37,10 @@ type
 
   MultistreamSelect* = object
     handlers*: seq[HandlerHolder]
-    codec*: string
+    codec*: seq[byte]
-    na: string
+    na*: seq[byte]
-    ls: string
+    ls*: seq[byte]
+    lp: LenPrefixed
 
   MultistreamHandshakeException* = object of CatchableError
 
@@ -47,27 +48,30 @@ proc newMultistreamHandshakeException*(): ref Exception {.inline.} =
   result = newException(MultistreamHandshakeException,
     "could not perform multistream handshake")
 
+var appendNl: Through[seq[byte]] = proc (i: Source[seq[byte]]): Source[seq[byte]] {.gcsafe.} =
   proc append(item: Future[seq[byte]]): Future[seq[byte]] {.async.} =
     result = await item
     result.add(byte('\n'))
 
-var appendNl: Through[seq[byte]] = proc (i: Source[seq[byte]]): Source[seq[byte]] {.gcsafe.} =
   return iterator(): Future[seq[byte]] {.closure.} =
     for item in i:
       yield append(item)
 
+var stripNl: Through[seq[byte]] = proc (i: Source[seq[byte]]): Source[seq[byte]] {.gcsafe.} =
   proc strip(item: Future[seq[byte]]): Future[seq[byte]] {.async.} =
     result = await item
-  if result[^1] == byte('\n'):
+    if result.len > 0 and result[^1] == byte('\n'):
       result.setLen(result.high)
 
-var stripNl: Through[seq[byte]] = proc (i: Source[seq[byte]]): Source[seq[byte]] {.gcsafe.} =
   return iterator(): Future[seq[byte]] {.closure.} =
     for item in i:
       yield strip(item)
 
 proc init*(M: type[MultistreamSelect]): MultistreamSelect =
-  M(codec: Codec, ls: Ls, na: Na)
+  M(codec: toSeq(Codec).mapIt( it.byte ),
+    ls: Ls.toBytes(),
+    na: Na.toBytes(),
+    lp: LenPrefixed.init())
 
 proc select*(m: MultistreamSelect,
              conn: Connection,
@@ -75,29 +79,26 @@ proc select*(m: MultistreamSelect,
              Future[string] {.async.} =
   trace "initiating handshake", codec = m.codec
   var pushable = Pushable[seq[byte]].init() # pushable source
-  var lp = LenPrefixed.init()
 
-  var sink = pipe(pushable,
+  var source = pipe(pushable,
                    appendNl,
-                  lp.encoder,
+                   m.lp.encoder,
-                  conn)
+                   conn.toThrough,
-
+                   m.lp.decoder,
-  let source = pipe(conn,
-                    lp.decoder,
                    stripNl)
 
   # handshake first
-  await pushable.push(cast[seq[byte]](m.codec))
+  await pushable.push(m.codec)
 
   # (common optimization) if we've got
   # protos send the first one out immediately
   # without waiting for the handshake response
   if protos.len > 0:
-    await pushable.push(cast[seq[byte]](protos[0]))
+    await pushable.push(protos[0].toBytes())
 
   # check for handshake result
-  result = cast[string](await source())
+  var res = await source()
-  if result != m.codec:
+  if res != m.codec:
     error "handshake failed", codec = result.toHex()
     raise newMultistreamHandshakeException()
 
@@ -106,18 +107,17 @@ proc select*(m: MultistreamSelect,
   while i < protos.len:
     # first read because we've the outstanding requirest above
     trace "reading requested proto"
-    for chunk in source:
+    res = await source()
-      result = cast[string](await chunk)
 
-    if result == protos[i]:
+    var protoBytes = protos[i].toBytes()
-      trace "succesfully selected ", proto = proto
+    if res == protoBytes:
-      break
+      trace "succesfully selected ", proto = protos[i]
+      return protos[i]
 
     if i > 0:
-      trace "selecting proto", proto = proto
+      trace "selecting proto", proto = protos[i]
-      await pushable.push(cast[seq[byte]](protos[i])) # select proto
+      await pushable.push(protoBytes) # select proto
     i.inc()
-  await sink
 
 proc select*(m: MultistreamSelect,
              conn: Connection,
@@ -130,92 +130,98 @@ proc select*(m: MultistreamSelect,
 proc select*(m: MultistreamSelect, conn: Connection): Future[bool] =
   m.select(conn, "")
 
-# proc list*(m: MultistreamSelect,
+proc list*(m: MultistreamSelect,
-#            conn: Connection): Future[seq[string]] {.async.} =
+           conn: Connection): Future[seq[string]] {.async.} =
-#   ## list remote protos requests on connection
+  ## list remote protos requests on connection
-#   if not await m.select(conn):
+  if not await m.select(conn):
-#     return
+    return
 
-#   await conn.write(m.ls) # send ls
+  var pushable = Pushable[seq[byte]].init()
+  var source = pipe(pushable,
+                    appendNl,
+                    m.lp.encoder,
+                    conn.toThrough,
+                    m.lp.decoder,
+                    stripNl)
 
-#   var list = newSeq[string]()
+  await pushable.push(m.ls) # send ls
-#   let ms = cast[string]((await conn.readLp()))
-#   for s in ms.split("\n"):
-#     if s.len() > 0:
-#       list.add(s)
 
-#   result = list
+  var list = newSeq[string]()
+  for chunk in source:
+    var msg = string.fromBytes((await chunk))
+    for s in msg.split("\n"):
+      if s.len() > 0:
+        list.add(s)
 
-# proc handle*(m: MultistreamSelect, conn: Connection) {.async, gcsafe.} =
+  result = list
-#   trace "handle: starting multistream handling"
-#   try:
-#     while not conn.closed:
-#       var ms = cast[string]((await conn.readLp()))
-#       ms.removeSuffix("\n")
 
-#       trace "handle: got request for ", ms
+proc handle*(m: MultistreamSelect, conn: Connection) {.async, gcsafe.} =
-#       if ms.len() <= 0:
+  trace "handle: starting multistream handling"
-#         trace "handle: invalid proto"
+  try:
-#         await conn.write(m.na)
+    var pushable = Pushable[seq[byte]].init()
+    var source = pipe(pushable,
+                      appendNl,
+                      m.lp.encoder,
+                      conn.toThrough,
+                      m.lp.decoder,
+                      stripNl)
 
-#       if m.handlers.len() == 0:
+    for chunk in source:
-#         trace "handle: sending `na` for protocol ", protocol = ms
+      var msg = string.fromBytes((await chunk))
-#         await conn.write(m.na)
+      trace "got request for ", msg
-#         continue
+      if msg.len <= 0:
+        trace "invalid proto"
+        await pushable.push(m.na)
 
-#       case ms:
+      if m.handlers.len() == 0:
-#         of "ls":
+        trace "sending `na` for protocol ", protocol = msg
-#           trace "handle: listing protos"
+        await pushable.push(m.na)
-#           var protos = ""
+        continue
-#           for h in m.handlers:
-#             protos &= (h.proto & "\n")
-#           await conn.writeLp(protos)
-#         of Codec:
-#           await conn.write(m.codec)
-#         else:
-#           for h in m.handlers:
-#             if (not isNil(h.match) and h.match(ms)) or ms == h.proto:
-#               trace "found handler for", protocol = ms
-#               await conn.writeLp((h.proto & "\n"))
-#               try:
-#                 await h.protocol.handler(conn, ms)
-#                 return
-#               except CatchableError as exc:
-#                 warn "exception while handling", msg = exc.msg
-#                 return
-#           warn "no handlers for ", protocol = ms
-#           await conn.write(m.na)
-#   except CatchableError as exc:
-#     trace "Exception occurred", exc = exc.msg
-#   finally:
-#     trace "leaving multistream loop"
 
-# proc addHandler*[T: LPProtocol](m: MultistreamSelect,
+      case msg:
-#                                 codec: string,
+        of Ls:
-#                                 protocol: T,
+          trace "listing protos"
-#                                 matcher: Matcher = nil) =
+          for h in m.handlers:
-#   ## register a protocol
+            await pushable.push(h.proto.toBytes())
-#   # TODO: This is a bug in chronicles,
+        of Codec:
-#   # it break if I uncoment this line.
+          trace "handling handshake"
-#   # Which is almost the same as the
+          await pushable.push(m.codec)
-#   # one on the next override of addHandler
+        else:
-#   #
+          for h in m.handlers:
-#   # trace "registering protocol", codec = codec
+            if (not isNil(h.match) and h.match(msg)) or msg == h.proto:
-#   m.handlers.add(HandlerHolder(proto: codec,
+              trace "found handler for", protocol = msg
-#                                protocol: protocol,
+              await pushable.push(h.proto.toBytes())
-#                                match: matcher))
+              try:
+                await h.protocol.handler(conn, msg)
+                return
+              except CatchableError as exc:
+                warn "exception while handling", msg = exc.msg
+                return
+          warn "no handlers for ", protocol = msg
+          await pushable.push(m.na)
+  except CatchableError as exc:
+    trace "Exception occurred", exc = exc.msg
+  finally:
+    trace "leaving multistream loop"
 
-# proc addHandler*[T: LPProtoHandler](m: MultistreamSelect,
+proc addHandler*(m: var MultistreamSelect,
-#                                     codec: string,
+                  codec: string,
-#                                     handler: T,
+                  protocol: LPProtocol,
-#                                     matcher: Matcher = nil) =
+                  matcher: Matcher = nil) =
-#   ## helper to allow registering pure handlers
+  ## register a protocol
+  trace "registering protocol", codec = codec
+  m.handlers.add(HandlerHolder(proto: codec,
+                               protocol: protocol,
+                               match: matcher))
 
-#   trace "registering proto handler", codec = codec
+proc addHandler*(m: var MultistreamSelect,
-#   let protocol = new LPProtocol
+                    codec: string,
-#   protocol.codec = codec
+                    handler: LPProtoHandler,
-#   protocol.handler = handler
+                    matcher: Matcher = nil) =
+  ## helper to allow registering pure handlers
 
-#   m.handlers.add(HandlerHolder(proto: codec,
+  trace "registering proto handler", codec = codec
-#                                protocol: protocol,
+  let protocol = LPProtocol(codec: codec, handler: handler)
-#                                match: matcher))
+  m.handlers.add(HandlerHolder(proto: codec,
+                               protocol: protocol,
+                               match: matcher))