Move code for sparse optimized copy to a dedicated method

Signed-off-by: Mario Loriedo <mario.loriedo@gmail.com>

pkg/machine/compression/generic.go

@@ -63,3 +63,13 @@ func (d *genericDecompressor) close() {
 		logrus.Errorf("Unable to close compressed file: %q", err)
 	}
 }
+
+func (d *genericDecompressor) sparseOptimizedCopy(w WriteSeekCloser, r io.Reader) error {
+	var err error
+	sparseWriter := NewSparseWriter(w)
+	defer func() {
+		err = sparseWriter.Close()
+	}()
+	_, err = io.Copy(sparseWriter, r)
+	return err
+}

pkg/machine/compression/gzip.go

@@ -27,13 +27,5 @@ func (d *gzipDecompressor) decompress(w WriteSeekCloser, r io.Reader) error {
 		}
 	}()
 
-	sparseWriter := NewSparseWriter(w)
+	return d.sparseOptimizedCopy(w, gzReader)
-	defer func() {
-		if err := sparseWriter.Close(); err != nil {
-			logrus.Errorf("Unable to close uncompressed file: %q", err)
-		}
-	}()
-
-	_, err = io.Copy(sparseWriter, gzReader)
-	return err
 }

pkg/machine/compression/uncompressed.go

@@ -2,8 +2,6 @@ package compression
 
 import (
 	"io"
-
-	"github.com/sirupsen/logrus"
 )
 
 type uncompressedDecompressor struct {
@@ -16,13 +14,5 @@ func newUncompressedDecompressor(compressedFilePath string) (*uncompressedDecomp
 }
 
 func (d *uncompressedDecompressor) decompress(w WriteSeekCloser, r io.Reader) error {
-	sparseWriter := NewSparseWriter(w)
+	return d.sparseOptimizedCopy(w, r)
-	defer func() {
-		if err := sparseWriter.Close(); err != nil {
-			logrus.Errorf("Unable to close uncompressed file: %q", err)
-		}
-	}()
-
-	_, err := io.Copy(sparseWriter, r)
-	return err
 }

pkg/machine/compression/zstd.go

@@ -4,7 +4,6 @@ import (
 	"io"
 
 	"github.com/klauspost/compress/zstd"
-	"github.com/sirupsen/logrus"
 )
 
 type zstdDecompressor struct {
@@ -23,13 +22,5 @@ func (d *zstdDecompressor) decompress(w WriteSeekCloser, r io.Reader) error {
 	}
 	defer zstdReader.Close()
 
-	sparseWriter := NewSparseWriter(w)
+	return d.sparseOptimizedCopy(w, zstdReader)
-	defer func() {
-		if err := sparseWriter.Close(); err != nil {
-			logrus.Errorf("Unable to close uncompressed file: %q", err)
-		}
-	}()
-
-	_, err = io.Copy(sparseWriter, zstdReader)
-	return err
 }