From cd4d4051ca6d36ebcda7bb3a0c61c742511f8df4 Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Thu, 28 Dec 2017 17:24:40 -0800
Subject: [PATCH] remove handler func support

1. It never actually worked (we always used the text match).
2. It made it impossible to list protocols.

reverts c9587f16af873eced8fd29ea66c9c777d5c35d09
---
 multistream.go | 81 ++++++++++++--------------------------------------
 1 file changed, 19 insertions(+), 62 deletions(-)

diff --git a/multistream.go b/multistream.go
index 4ac48fe..23d2c9f 100644
--- a/multistream.go
+++ b/multistream.go
@@ -23,25 +23,16 @@ const ProtocolID = "/multistream/1.0.0"
 // handle a protocol/stream.
 type HandlerFunc func(protocol string, rwc io.ReadWriteCloser) error
 
-// Handler is a wrapper to HandlerFunc which attaches a name (protocol) and a
-// match function which can optionally be used to select a handler by other
-// means than the name.
-type Handler struct {
-	MatchFunc func(string) bool
-	Handle    HandlerFunc
-	AddName   string
-}
-
 // MultistreamMuxer is a muxer for multistream. Depending on the stream
 // protocol tag it will select the right handler and hand the stream off to it.
 type MultistreamMuxer struct {
 	handlerlock sync.Mutex
-	handlers    []Handler
+	handlers    map[string]HandlerFunc
 }
 
 // NewMultistreamMuxer creates a muxer.
 func NewMultistreamMuxer() *MultistreamMuxer {
-	return new(MultistreamMuxer)
+	return &MultistreamMuxer{handlers: make(map[string]HandlerFunc)}
 }
 
 func writeUvarint(w io.Writer, i uint64) error {
@@ -107,54 +98,26 @@ func Ls(rw io.ReadWriter) ([]string, error) {
 	return out, nil
 }
 
-func fulltextMatch(s string) func(string) bool {
-	return func(a string) bool {
-		return a == s
-	}
-}
-
 // AddHandler attaches a new protocol handler to the muxer.
 func (msm *MultistreamMuxer) AddHandler(protocol string, handler HandlerFunc) {
-	msm.AddHandlerWithFunc(protocol, fulltextMatch(protocol), handler)
-}
-
-// AddHandlerWithFunc attaches a new protocol handler to the muxer with a match.
-// If the match function returns true for a given protocol tag, the protocol
-// will be selected even if the handler name and protocol tags are different.
-func (msm *MultistreamMuxer) AddHandlerWithFunc(protocol string, match func(string) bool, handler HandlerFunc) {
 	msm.handlerlock.Lock()
-	msm.removeHandler(protocol)
-	msm.handlers = append(msm.handlers, Handler{
-		MatchFunc: fulltextMatch(protocol),
-		Handle:    handler,
-		AddName:   protocol,
-	})
+	msm.handlers[protocol] = handler
 	msm.handlerlock.Unlock()
 }
 
-// RemoveHandler removes the handler with the given name from the muxer.
+// RemoveHandler removes the protocol handler from the muxer.
 func (msm *MultistreamMuxer) RemoveHandler(protocol string) {
 	msm.handlerlock.Lock()
-	defer msm.handlerlock.Unlock()
-
-	msm.removeHandler(protocol)
-}
-
-func (msm *MultistreamMuxer) removeHandler(protocol string) {
-	for i, h := range msm.handlers {
-		if h.AddName == protocol {
-			msm.handlers = append(msm.handlers[:i], msm.handlers[i+1:]...)
-			return
-		}
-	}
+	delete(msm.handlers, protocol)
+	msm.handlerlock.Unlock()
 }
 
 // Protocols returns the list of handler-names added to this this muxer.
 func (msm *MultistreamMuxer) Protocols() []string {
 	var out []string
 	msm.handlerlock.Lock()
-	for _, h := range msm.handlers {
-		out = append(out, h.AddName)
+	for k := range msm.handlers {
+		out = append(out, k)
 	}
 	msm.handlerlock.Unlock()
 	return out
@@ -164,17 +127,11 @@ func (msm *MultistreamMuxer) Protocols() []string {
 // fails because of a ProtocolID mismatch.
 var ErrIncorrectVersion = errors.New("client connected with incorrect version")
 
-func (msm *MultistreamMuxer) findHandler(proto string) *Handler {
+func (msm *MultistreamMuxer) findHandler(proto string) (HandlerFunc, bool) {
 	msm.handlerlock.Lock()
 	defer msm.handlerlock.Unlock()
-
-	for _, h := range msm.handlers {
-		if h.MatchFunc(proto) {
-			return &h
-		}
-	}
-
-	return nil
+	f, ok := msm.handlers[proto]
+	return f, ok
 }
 
 // NegotiateLazy performs protocol selection and returns
@@ -243,8 +200,8 @@ loop:
 				return nil, "", nil, err
 			}
 		default:
-			h := msm.findHandler(tok)
-			if h == nil {
+			h, ok := msm.findHandler(tok)
+			if !ok {
 				select {
 				case pval <- "na":
 				case err := <-writeErr:
@@ -262,7 +219,7 @@ loop:
 			}
 
 			// hand off processing to the sub-protocol handler
-			return lzc, tok, h.Handle, nil
+			return lzc, tok, h, nil
 		}
 	}
 }
@@ -301,8 +258,8 @@ loop:
 				return "", nil, err
 			}
 		default:
-			h := msm.findHandler(tok)
-			if h == nil {
+			h, ok := msm.findHandler(tok)
+			if !ok {
 				err := delimWriteBuffered(rwc, []byte("na"))
 				if err != nil {
 					return "", nil, err
@@ -316,7 +273,7 @@ loop:
 			}
 
 			// hand off processing to the sub-protocol handler
-			return tok, h.Handle, nil
+			return tok, h, nil
 		}
 	}
 
@@ -332,8 +289,8 @@ func (msm *MultistreamMuxer) Ls(w io.Writer) error {
 		return err
 	}
 
-	for _, h := range msm.handlers {
-		err := delimWrite(buf, []byte(h.AddName))
+	for k := range msm.handlers {
+		err := delimWrite(buf, []byte(k))
 		if err != nil {
 			msm.handlerlock.Unlock()
 			return err