pushWriter: refactor reset pipe logic into separate function

Signed-off-by: Justin Chadwell <me@jedevc.com>

remotes/docker/pusher.go

@@ -384,6 +384,27 @@ func (pw *pushWriter) setResponse(resp *http.Response) {
 	}
 }
 
+func (pw *pushWriter) replacePipe(p *io.PipeWriter) error {
+	if pw.pipe == nil {
+		pw.pipe = p
+		return nil
+	}
+
+	pw.pipe.CloseWithError(content.ErrReset)
+	pw.pipe = p
+
+	// If content has already been written, the bytes
+	// cannot be written again and the caller must reset
+	status, err := pw.tracker.GetStatus(pw.ref)
+	if err != nil {
+		return err
+	}
+	status.Offset = 0
+	status.UpdatedAt = time.Now()
+	pw.tracker.SetStatus(pw.ref, status)
+	return content.ErrReset
+}
+
 func (pw *pushWriter) Write(p []byte) (n int, err error) {
 	status, err := pw.tracker.GetStatus(pw.ref)
 	if err != nil {
@@ -395,26 +416,14 @@ func (pw *pushWriter) Write(p []byte) (n int, err error) {
 		case <-pw.done:
 			return 0, io.ErrClosedPipe
 		case p := <-pw.pipeC:
-			pw.pipe = p
+			pw.replacePipe(p)
 		}
 	} else {
 		select {
 		case <-pw.done:
 			return 0, io.ErrClosedPipe
 		case p := <-pw.pipeC:
-			pw.pipe.CloseWithError(content.ErrReset)
-			pw.pipe = p
-
-			// If content has already been written, the bytes
-			// cannot be written again and the caller must reset
-			status, err := pw.tracker.GetStatus(pw.ref)
-			if err != nil {
-				return 0, err
-			}
-			status.Offset = 0
-			status.UpdatedAt = time.Now()
-			pw.tracker.SetStatus(pw.ref, status)
-			return 0, content.ErrReset
+			return 0, pw.replacePipe(p)
 		default:
 		}
 	}
@@ -427,19 +436,7 @@ func (pw *pushWriter) Write(p []byte) (n int, err error) {
 		case <-pw.done:
 		case err = <-pw.errC:
 		case p := <-pw.pipeC:
-			pw.pipe.CloseWithError(content.ErrReset)
-			pw.pipe = p
-
-			// If content has already been written, the bytes
-			// cannot be written again and the caller must reset
-			status, err := pw.tracker.GetStatus(pw.ref)
-			if err != nil {
-				return 0, err
-			}
-			status.Offset = 0
-			status.UpdatedAt = time.Now()
-			pw.tracker.SetStatus(pw.ref, status)
-			return 0, content.ErrReset
+			return 0, pw.replacePipe(p)
 		}
 	}
 	status.Offset += int64(n)
@@ -502,19 +499,7 @@ func (pw *pushWriter) Commit(ctx context.Context, size int64, expected digest.Di
 		// check whether the pipe has changed in the commit, because sometimes Write
 		// can complete successfully, but the pipe may have changed. In that case, the
 		// content needs to be reset.
-		pw.pipe.CloseWithError(content.ErrReset)
-		pw.pipe = p
-
-		// If content has already been written, the bytes
-		// cannot be written again and the caller must reset
-		status, err := pw.tracker.GetStatus(pw.ref)
-		if err != nil {
-			return err
-		}
-		status.Offset = 0
-		status.UpdatedAt = time.Now()
-		pw.tracker.SetStatus(pw.ref, status)
-		return content.ErrReset
+		return pw.replacePipe(p)
 	}
 
 	// 201 is specified return status, some registries return