From: Matt Joiner <anacrolix@gmail.com>
Date: Fri, 22 Aug 2014 07:39:18 +0000 (+1000)
Subject: Clarify EOF in message decoding
X-Git-Tag: v1.0.0~1617
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=a2fabedfa2354aac39a5fb1260a906c6574cc7ee;p=btrtrc.git

Clarify EOF in message decoding
---

diff --git a/peer_protocol/protocol.go b/peer_protocol/protocol.go
index 87cf38d8..db32ac59 100644
--- a/peer_protocol/protocol.go
+++ b/peer_protocol/protocol.go
@@ -109,10 +109,14 @@ type Decoder struct {
 	MaxLength Integer // TODO: Should this include the length header or not?
 }
 
+// io.EOF is returned if the source terminates cleanly on a message boundary.
 func (d *Decoder) Decode(msg *Message) (err error) {
 	var length Integer
 	err = binary.Read(d.R, binary.BigEndian, &length)
 	if err != nil {
+		if err != io.EOF {
+			err = fmt.Errorf("error reading message length: %s", err)
+		}
 		return
 	}
 	if length > d.MaxLength {
@@ -125,10 +129,13 @@ func (d *Decoder) Decode(msg *Message) (err error) {
 	msg.Keepalive = false
 	b := make([]byte, length)
 	_, err = io.ReadFull(d.R, b)
-	if err == io.EOF {
-		err = io.ErrUnexpectedEOF
-	}
 	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		if err != io.ErrUnexpectedEOF {
+			err = fmt.Errorf("error reading message: %s", err)
+		}
 		return
 	}
 	r := bytes.NewReader(b)
diff --git a/peer_protocol/protocol_test.go b/peer_protocol/protocol_test.go
index 807f1dd8..d2fc8d4b 100644
--- a/peer_protocol/protocol_test.go
+++ b/peer_protocol/protocol_test.go
@@ -3,7 +3,6 @@ package peer_protocol
 import (
 	"bufio"
 	"bytes"
-	"io"
 	"strings"
 	"testing"
 )
@@ -103,8 +102,8 @@ func TestUnexpectedEOF(t *testing.T) {
 			MaxLength: 42,
 		}
 		err := dec.Decode(msg)
-		if err != io.ErrUnexpectedEOF {
-			t.Fatalf("expected ErrUnexpectedEOF decoding %q, got %s", stream, err)
+		if err == nil {
+			t.Fatalf("expected an error decoding %q", stream)
 		}
 	}
 }