From 21d8cf378407f4405ea69a864522372a814ef911 Mon Sep 17 00:00:00 2001
From: "M. J. Fromberger" <michael.j.fromberger@gmail.com>
Date: Wed, 5 May 2021 10:41:28 -0400
Subject: [PATCH] channel: Remove the Varint framing.

https://github.com/creachadair/jrpc2/issues/46#issuecomment-831963902
---
 channel/bench_test.go        |  1 -
 channel/channel_test.go      |  1 -
 channel/chanutil/chanutil.go |  8 ++---
 channel/varint.go            | 64 ------------------------------------
 server/loop_test.go          |  2 +-
 5 files changed, 4 insertions(+), 72 deletions(-)
 delete mode 100644 channel/varint.go

diff --git a/channel/bench_test.go b/channel/bench_test.go
index bbdb47f..5233d9b 100644
--- a/channel/bench_test.go
+++ b/channel/bench_test.go
@@ -43,7 +43,6 @@ func BenchmarkFramingCost(b *testing.B) {
 		{"LSP", channel.LSP},
 		{"NUL", channel.Split('\x00')},
 		{"RawJSON", channel.RawJSON},
-		{"Varint", channel.Varint},
 	}
 
 	msg, err := json.Marshal(benchMessage)
diff --git a/channel/channel_test.go b/channel/channel_test.go
index e6d96f0..b04788d 100644
--- a/channel/channel_test.go
+++ b/channel/channel_test.go
@@ -84,7 +84,6 @@ var tests = []struct {
 	{"RS", Split('\x1e')},
 	{"RawJSON", RawJSON},
 	{"StrictHeader", StrictHeader("text/plain")},
-	{"Varint", Varint},
 }
 
 // N.B. the messages in this list must be valid JSON, since the RawJSON framing
diff --git a/channel/chanutil/chanutil.go b/channel/chanutil/chanutil.go
index 499400c..0cd075b 100644
--- a/channel/chanutil/chanutil.go
+++ b/channel/chanutil/chanutil.go
@@ -16,7 +16,6 @@ import (
 //    line     -- corresponds to channel.Line
 //    lsp      -- corresponds to channel.LSP
 //    raw      -- corresponds to channel.RawJSON
-//    varint   -- corresponds to channel.Varint
 //
 func Framing(name string) channel.Framing {
 	if t := strings.TrimPrefix(name, "header:"); t != name {
@@ -29,8 +28,7 @@ func Framing(name string) channel.Framing {
 }
 
 var framings = map[string]channel.Framing{
-	"line":   channel.Line,
-	"lsp":    channel.LSP,
-	"raw":    channel.RawJSON,
-	"varint": channel.Varint,
+	"line": channel.Line,
+	"lsp":  channel.LSP,
+	"raw":  channel.RawJSON,
 }
diff --git a/channel/varint.go b/channel/varint.go
deleted file mode 100644
index cb46b6d..0000000
--- a/channel/varint.go
+++ /dev/null
@@ -1,64 +0,0 @@
-package channel
-
-import (
-	"bufio"
-	"bytes"
-	"encoding/binary"
-	"io"
-)
-
-// Varint is a framing that transmits and receives messages on r and wc, with
-// each message prefixed by its length encoded in a varint as defined by the
-// encoding/binary package.
-func Varint(r io.Reader, wc io.WriteCloser) Channel {
-	return &varint{
-		wc:  wc,
-		rd:  bufio.NewReader(r),
-		buf: bytes.NewBuffer(nil),
-	}
-}
-
-// A varint implements Channel for varint-prefixed messages.
-type varint struct {
-	wc  io.WriteCloser
-	rd  *bufio.Reader
-	buf *bytes.Buffer
-}
-
-// Send implements part of the Channel interface. It encodes len(msg) as a
-// varint, concatenates it with the message body, and writes the framed message
-// to the underlying writer.
-func (v *varint) Send(msg []byte) error {
-	var ln [binary.MaxVarintLen64]byte
-	nb := binary.PutUvarint(ln[:], uint64(len(msg)))
-
-	v.buf.Reset()
-	v.buf.Grow(nb + len(msg))
-	v.buf.Write(ln[:nb])
-	v.buf.Write(msg)
-	_, err := v.wc.Write(v.buf.Next(v.buf.Len()))
-	return err
-}
-
-// Recv implements part of the Channel interface. It decodes a varint message
-// length then reads that many bytes from the underlying reader.
-func (v *varint) Recv() ([]byte, error) {
-	ln, err := v.decode()
-	if err != nil {
-		return nil, err
-	}
-	out := make([]byte, ln)
-	nr, err := io.ReadFull(v.rd, out)
-	return out[:nr], err
-}
-
-// Close implements part of the Channel interface.
-func (v *varint) Close() error { return v.wc.Close() }
-
-func (v *varint) decode() (int, error) {
-	ln, err := binary.ReadUvarint(v.rd)
-	if err != nil {
-		return 0, err
-	}
-	return int(ln), nil
-}
diff --git a/server/loop_test.go b/server/loop_test.go
index a13a9c2..df61a16 100644
--- a/server/loop_test.go
+++ b/server/loop_test.go
@@ -13,7 +13,7 @@ import (
 	"github.com/creachadair/jrpc2/handler"
 )
 
-var newChan = channel.Varint
+var newChan = channel.Line
 
 // A static test service that returns the same thing each time.
 var testService = NewStatic(handler.Map{