X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/b310fc04b9e60b974f4bfc2c86a5c45ecd7c65f2..bcf8d387aaed911d955e1f26142caba785cd4e07:/sdk/go/keepclient/hashcheck.go

diff --git a/sdk/go/keepclient/hashcheck.go b/sdk/go/keepclient/hashcheck.go
index b97df78d96..9295c14cc2 100644
--- a/sdk/go/keepclient/hashcheck.go
+++ b/sdk/go/keepclient/hashcheck.go
@@ -1,3 +1,7 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+
 package keepclient
 
 import (
@@ -31,7 +35,7 @@ func (this HashCheckingReader) Read(p []byte) (n int, err error) {
 		this.Hash.Write(p[:n])
 	}
 	if err == io.EOF {
-		sum := this.Hash.Sum(make([]byte, 0, this.Hash.Size()))
+		sum := this.Hash.Sum(nil)
 		if fmt.Sprintf("%x", sum) != this.Check {
 			err = BadChecksum
 		}
@@ -39,8 +43,9 @@ func (this HashCheckingReader) Read(p []byte) (n int, err error) {
 	return n, err
 }
 
-// WriteTo writes the entire contents of this.Reader to dest.  Returns
-// BadChecksum if the checksum doesn't match.
+// WriteTo writes the entire contents of this.Reader to dest. Returns
+// BadChecksum if writing is successful but the checksum doesn't
+// match.
 func (this HashCheckingReader) WriteTo(dest io.Writer) (written int64, err error) {
 	if writeto, ok := this.Reader.(io.WriterTo); ok {
 		written, err = writeto.WriteTo(io.MultiWriter(dest, this.Hash))
@@ -48,13 +53,16 @@ func (this HashCheckingReader) WriteTo(dest io.Writer) (written int64, err error
 		written, err = io.Copy(io.MultiWriter(dest, this.Hash), this.Reader)
 	}
 
-	sum := this.Hash.Sum(make([]byte, 0, this.Hash.Size()))
+	if err != nil {
+		return written, err
+	}
 
+	sum := this.Hash.Sum(nil)
 	if fmt.Sprintf("%x", sum) != this.Check {
-		err = BadChecksum
+		return written, BadChecksum
 	}
 
-	return written, err
+	return written, nil
 }
 
 // Close reads all remaining data from the underlying Reader and
@@ -64,19 +72,16 @@ func (this HashCheckingReader) Close() (err error) {
 	_, err = io.Copy(this.Hash, this.Reader)
 
 	if closer, ok := this.Reader.(io.Closer); ok {
-		err2 := closer.Close()
-		if err2 != nil && err == nil {
-			return err2
+		closeErr := closer.Close()
+		if err == nil {
+			err = closeErr
 		}
 	}
 	if err != nil {
 		return err
 	}
-
-	sum := this.Hash.Sum(make([]byte, 0, this.Hash.Size()))
-	if fmt.Sprintf("%x", sum) != this.Check {
-		err = BadChecksum
+	if fmt.Sprintf("%x", this.Hash.Sum(nil)) != this.Check {
+		return BadChecksum
 	}
-
-	return err
+	return nil
 }