Decouple github.com/jackc/chunkreader

backend.go

@@ -4,12 +4,11 @@ import (
 	"encoding/binary"
 	"io"
 
-	"github.com/jackc/chunkreader"
 	"github.com/pkg/errors"
 )
 
 type Backend struct {
-	cr *chunkreader.ChunkReader
+	cr ChunkReader
 	w  io.Writer
 
 	// Frontend message flyweights
@@ -31,8 +30,7 @@ type Backend struct {
 	partialMsg bool
 }
 
-func NewBackend(r io.Reader, w io.Writer) (*Backend, error) {
+func NewBackend(cr ChunkReader, w io.Writer) (*Backend, error) {
-	cr := chunkreader.NewChunkReader(r)
 	return &Backend{cr: cr, w: w}, nil
 }
 

backend_test.go

@@ -12,7 +12,7 @@ func TestBackendReceiveInterrupted(t *testing.T) {
 	server := &interruptReader{}
 	server.push([]byte{'Q', 0, 0, 0, 6})
 
-	backend, err := pgproto3.NewBackend(server, nil)
+	backend, err := pgproto3.NewBackend(pgproto3.NewChunkReader(server), nil)
 	if err != nil {
 		t.Fatal(err)
 	}

chunkreader.go

@@ -0,0 +1,18 @@
+package pgproto3
+
+import (
+	"io"
+
+	"github.com/jackc/chunkreader"
+)
+
+// ChunkReader is an interface to decouple github.com/jackc/chunkreader from this package.
+type ChunkReader interface {
+	// Next returns buf filled with the next n bytes. If an error occurs, buf will be nil. Next must
+	// not reuse buf. In case of error, Next must preserve partially read data.
+	Next(n int) (buf []byte, err error)
+}
+
+func NewChunkReader(r io.Reader) ChunkReader {
+	return chunkreader.NewChunkReader(r)
+}

frontend.go

@@ -4,12 +4,11 @@ import (
 	"encoding/binary"
 	"io"
 
-	"github.com/jackc/chunkreader"
 	"github.com/pkg/errors"
 )
 
 type Frontend struct {
-	cr *chunkreader.ChunkReader
+	cr ChunkReader
 	w  io.Writer
 
 	// Backend message flyweights
@@ -42,8 +41,7 @@ type Frontend struct {
 	partialMsg bool
 }
 
-func NewFrontend(r io.Reader, w io.Writer) (*Frontend, error) {
+func NewFrontend(cr ChunkReader, w io.Writer) (*Frontend, error) {
-	cr := chunkreader.NewChunkReader(r)
 	return &Frontend{cr: cr, w: w}, nil
 }
 

frontend_test.go

@@ -37,7 +37,7 @@ func TestFrontendReceiveInterrupted(t *testing.T) {
 	server := &interruptReader{}
 	server.push([]byte{'Z', 0, 0, 0, 5})
 
-	frontend, err := pgproto3.NewFrontend(server, nil)
+	frontend, err := pgproto3.NewFrontend(pgproto3.NewChunkReader(server), nil)
 	if err != nil {
 		t.Fatal(err)
 	}