transport.NewHTTPReadSeeker: return concrete type, deprecate ReadSeek…

…Closer

General convention is to define interfaces on the receiver side, and
to return concrete types.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

registry/client/transport/http_reader.go

@@ -20,25 +20,26 @@ var (
 )
 
 // ReadSeekCloser combines io.ReadSeeker with io.Closer.
-type ReadSeekCloser interface {
-	io.ReadSeeker
-	io.Closer
-}
+//
+// Deprecated: use [io.ReadSeekCloser].
+type ReadSeekCloser = io.ReadSeekCloser
 
 // NewHTTPReadSeeker handles reading from an HTTP endpoint using a GET
 // request. When seeking and starting a read from a non-zero offset
 // the a "Range" header will be added which sets the offset.
+//
 // TODO(dmcgowan): Move this into a separate utility package
-func NewHTTPReadSeeker(ctx context.Context, client *http.Client, url string, errorHandler func(*http.Response) error) ReadSeekCloser {
-	return &httpReadSeeker{
+func NewHTTPReadSeeker(ctx context.Context, client *http.Client, url string, errorHandler func(*http.Response) error) *HTTPReadSeeker {
+	return &HTTPReadSeeker{
 		ctx:          ctx,
 		client:       client,
 		url:          url,
 		errorHandler: errorHandler,
 	}
 }
 
-type httpReadSeeker struct {
+// HTTPReadSeeker implements an [io.ReadSeekCloser].
+type HTTPReadSeeker struct {
 	ctx    context.Context
 	client *http.Client
 	url    string
@@ -63,7 +64,7 @@ type httpReadSeeker struct {
 	err        error
 }
 
-func (hrs *httpReadSeeker) Read(p []byte) (n int, err error) {
+func (hrs *HTTPReadSeeker) Read(p []byte) (n int, err error) {
 	if hrs.err != nil {
 		return 0, hrs.err
 	}
@@ -92,7 +93,7 @@ func (hrs *httpReadSeeker) Read(p []byte) (n int, err error) {
 	return n, err
 }
 
-func (hrs *httpReadSeeker) Seek(offset int64, whence int) (int64, error) {
+func (hrs *HTTPReadSeeker) Seek(offset int64, whence int) (int64, error) {
 	if hrs.err != nil {
 		return 0, hrs.err
 	}
@@ -135,7 +136,7 @@ func (hrs *httpReadSeeker) Seek(offset int64, whence int) (int64, error) {
 	return hrs.seekOffset, err
 }
 
-func (hrs *httpReadSeeker) Close() error {
+func (hrs *HTTPReadSeeker) Close() error {
 	if hrs.err != nil {
 		return hrs.err
 	}
@@ -152,7 +153,7 @@ func (hrs *httpReadSeeker) Close() error {
 	return nil
 }
 
-func (hrs *httpReadSeeker) reset() {
+func (hrs *HTTPReadSeeker) reset() {
 	if hrs.err != nil {
 		return
 	}
@@ -162,7 +163,7 @@ func (hrs *httpReadSeeker) reset() {
 	}
 }
 
-func (hrs *httpReadSeeker) reader() (io.Reader, error) {
+func (hrs *HTTPReadSeeker) reader() (io.Reader, error) {
 	if hrs.err != nil {
 		return nil, hrs.err
 	}