utils: binary reader, add ReadUntilFromBufioReader()

Signed-off-by: Arran Walker <arran.walker@fiveturns.org>

plumbing/format/index/decoder.go

@@ -354,14 +354,14 @@ func (d *treeExtensionDecoder) Decode(t *Tree) error {
 func (d *treeExtensionDecoder) readEntry() (*TreeEntry, error) {
 	e := &TreeEntry{}
 
-	path, err := binary.ReadUntil(d.r, '\x00')
+	path, err := binary.ReadUntilFromBufioReader(d.r, '\x00')
 	if err != nil {
 		return nil, err
 	}
 
 	e.Path = string(path)
 
-	count, err := binary.ReadUntil(d.r, ' ')
+	count, err := binary.ReadUntilFromBufioReader(d.r, ' ')
 	if err != nil {
 		return nil, err
 	}
@@ -378,7 +378,7 @@ func (d *treeExtensionDecoder) readEntry() (*TreeEntry, error) {
 	}
 
 	e.Entries = i
-	trees, err := binary.ReadUntil(d.r, '\n')
+	trees, err := binary.ReadUntilFromBufioReader(d.r, '\n')
 	if err != nil {
 		return nil, err
 	}
@@ -418,7 +418,7 @@ func (d *resolveUndoDecoder) readEntry() (*ResolveUndoEntry, error) {
 		Stages: make(map[Stage]plumbing.Hash),
 	}
 
-	path, err := binary.ReadUntil(d.r, '\x00')
+	path, err := binary.ReadUntilFromBufioReader(d.r, '\x00')
 	if err != nil {
 		return nil, err
 	}
@@ -444,7 +444,7 @@ func (d *resolveUndoDecoder) readEntry() (*ResolveUndoEntry, error) {
 }
 
 func (d *resolveUndoDecoder) readStage(e *ResolveUndoEntry, s Stage) error {
-	ascii, err := binary.ReadUntil(d.r, '\x00')
+	ascii, err := binary.ReadUntilFromBufioReader(d.r, '\x00')
 	if err != nil {
 		return err
 	}

utils/binary/read.go

@@ -25,15 +25,6 @@ func Read(r io.Reader, data ...interface{}) error {
 
 // ReadUntil reads from r untin delim is found
 func ReadUntil(r io.Reader, delim byte) ([]byte, error) {
-	if bufr, ok := r.(*bufio.Reader); ok {
-		value, err := bufr.ReadBytes(delim)
-		if err != nil || len(value) == 0 {
-			return nil, err
-		}
-
-		return value[:len(value)-1], nil
-	}
-
 	var buf [1]byte
 	value := make([]byte, 0, 16)
 	for {
@@ -53,6 +44,17 @@ func ReadUntil(r io.Reader, delim byte) ([]byte, error) {
 	}
 }
 
+// ReadUntilFromBufioReader is like bufio.ReadBytes but drops the delimiter
+// from the result.
+func ReadUntilFromBufioReader(r *bufio.Reader, delim byte) ([]byte, error) {
+	value, err := r.ReadBytes(delim)
+	if err != nil || len(value) == 0 {
+		return nil, err
+	}
+
+	return value[:len(value)-1], nil
+}
+
 // ReadVariableWidthInt reads and returns an int in Git VLQ special format:
 //
 // Ordinary VLQ has some redundancies, example:  the number 358 can be

utils/binary/read_test.go

@@ -1,6 +1,7 @@
 package binary
 
 import (
+	"bufio"
 	"bytes"
 	"encoding/binary"
 	"testing"
@@ -39,6 +40,15 @@ func (s *BinarySuite) TestReadUntil(c *C) {
 	c.Assert(string(b), Equals, "foo")
 }
 
+func (s *BinarySuite) TestReadUntilFromBufioReader(c *C) {
+	buf := bufio.NewReader(bytes.NewBuffer([]byte("foo bar")))
+
+	b, err := ReadUntilFromBufioReader(buf, ' ')
+	c.Assert(err, IsNil)
+	c.Assert(b, HasLen, 3)
+	c.Assert(string(b), Equals, "foo")
+}
+
 func (s *BinarySuite) TestReadVariableWidthInt(c *C) {
 	buf := bytes.NewBuffer([]byte{129, 110})