Removes WrapReader boilerplate for updates to libchan

libchan now supports io.ReadCloser and io.WriteCloser, so we don't need
io.ReadWriteCloser wrapping

storagedriver/ipc/client.go

@@ -155,7 +155,7 @@ func (driver *StorageDriverClient) GetContent(path string) ([]byte, error) {
 func (driver *StorageDriverClient) PutContent(path string, contents []byte) error {
 	receiver, remoteSender := libchan.Pipe()
 
-	params := map[string]interface{}{"Path": path, "Reader": WrapReader(bytes.NewReader(contents))}
+	params := map[string]interface{}{"Path": path, "Reader": ioutil.NopCloser(bytes.NewReader(contents))}
 	err := driver.sender.Send(&Request{Type: "PutContent", Parameters: params, ResponseChannel: remoteSender})
 	if err != nil {
 		return err
@@ -199,7 +199,7 @@ func (driver *StorageDriverClient) ReadStream(path string, offset uint64) (io.Re
 func (driver *StorageDriverClient) WriteStream(path string, offset, size uint64, reader io.ReadCloser) error {
 	receiver, remoteSender := libchan.Pipe()
 
-	params := map[string]interface{}{"Path": path, "Offset": offset, "Size": size, "Reader": WrapReader(reader)}
+	params := map[string]interface{}{"Path": path, "Offset": offset, "Size": size, "Reader": ioutil.NopCloser(reader)}
 	err := driver.sender.Send(&Request{Type: "WriteStream", Parameters: params, ResponseChannel: remoteSender})
 	if err != nil {
 		return err

storagedriver/ipc/ipc.go

@@ -1,10 +1,8 @@
 package ipc
 
 import (
-	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"reflect"
 
 	"github.com/docker/libchan"
@@ -18,29 +16,6 @@ type Request struct {
 	ResponseChannel libchan.Sender
 }
 
-// noWriteReadWriteCloser is a simple wrapper around an io.ReadCloser that implements the
-// io.ReadWriteCloser interface
-// Calls to Write are disallowed and will return an error
-type noWriteReadWriteCloser struct {
-	io.ReadCloser
-}
-
-func (r noWriteReadWriteCloser) Write(p []byte) (n int, err error) {
-	return 0, errors.New("Write unsupported")
-}
-
-// WrapReader wraps an io.Reader as an io.ReadWriteCloser with a nop Close and unsupported Write
-// Has no effect when an io.ReadWriteCloser is passed in
-func WrapReader(reader io.Reader) io.ReadWriteCloser {
-	if readWriteCloser, ok := reader.(io.ReadWriteCloser); ok {
-		return readWriteCloser
-	} else if readCloser, ok := reader.(io.ReadCloser); ok {
-		return noWriteReadWriteCloser{readCloser}
-	} else {
-		return noWriteReadWriteCloser{ioutil.NopCloser(reader)}
-	}
-}
-
 type responseError struct {
 	Type    string
 	Message string
@@ -65,7 +40,7 @@ func (err *responseError) Error() string {
 
 // ReadStreamResponse is a response for a ReadStream request
 type ReadStreamResponse struct {
-	Reader io.ReadWriteCloser
+	Reader io.ReadCloser
 	Error  *responseError
 }
 

storagedriver/ipc/server.go

@@ -68,7 +68,7 @@ func handleRequest(driver storagedriver.StorageDriver, request Request) {
 		if err != nil {
 			response = ReadStreamResponse{Error: ResponseError(err)}
 		} else {
-			response = ReadStreamResponse{Reader: WrapReader(bytes.NewReader(content))}
+			response = ReadStreamResponse{Reader: ioutil.NopCloser(bytes.NewReader(content))}
 		}
 		err = request.ResponseChannel.Send(&response)
 		if err != nil {
@@ -98,7 +98,7 @@ func handleRequest(driver storagedriver.StorageDriver, request Request) {
 		if err != nil {
 			response = ReadStreamResponse{Error: ResponseError(err)}
 		} else {
-			response = ReadStreamResponse{Reader: WrapReader(reader)}
+			response = ReadStreamResponse{Reader: ioutil.NopCloser(reader)}
 		}
 		err = request.ResponseChannel.Send(&response)
 		if err != nil {