p2p: use package rlp to encode messages

Message encoding functions have been renamed to catch any uses.
The switch to the new encoder can cause subtle incompatibilities.
If there are any users outside of our tree, they will at least be
alerted that there was a change.

NewMsg no longer exists. The replacements for EncodeMsg are called
Send and SendItems.

p2p/message_test.go

@@ -5,33 +5,17 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"runtime"
 	"strings"
 	"testing"
 	"time"
 )
 
-func TestNewMsg(t *testing.T) {
-	msg := NewMsg(3, 1, "000")
-	if msg.Code != 3 {
-		t.Errorf("incorrect code %d, want %d", msg.Code)
-	}
-	expect := unhex("c50183303030")
-	if msg.Size != uint32(len(expect)) {
-		t.Errorf("incorrect size %d, want %d", msg.Size, len(expect))
-	}
-	pl, _ := ioutil.ReadAll(msg.Payload)
-	if !bytes.Equal(pl, expect) {
-		t.Errorf("incorrect payload content, got %x, want %x", pl, expect)
-	}
-}
-
 func ExampleMsgPipe() {
 	rw1, rw2 := MsgPipe()
 	go func() {
-		EncodeMsg(rw1, 8, []byte{0, 0})
-		EncodeMsg(rw1, 5, []byte{1, 1})
+		Send(rw1, 8, [][]byte{{0, 0}})
+		Send(rw1, 5, [][]byte{{1, 1}})
 		rw1.Close()
 	}()
 
@@ -40,7 +24,7 @@ func ExampleMsgPipe() {
 		if err != nil {
 			break
 		}
-		var data [1][]byte
+		var data [][]byte
 		msg.Decode(&data)
 		fmt.Printf("msg: %d, %x\n", msg.Code, data[0])
 	}
@@ -55,7 +39,7 @@ loop:
 		rw1, rw2 := MsgPipe()
 		done := make(chan struct{})
 		go func() {
-			if err := EncodeMsg(rw1, 1); err == nil {
+			if err := SendItems(rw1, 1); err == nil {
 				t.Error("EncodeMsg returned nil error")
 			} else if err != ErrPipeClosed {
 				t.Error("EncodeMsg returned wrong error: got %v, want %v", err, ErrPipeClosed)