build-sys: import build system from darvaza.org/core

Signed-off-by: Alejandro Mery <amery@jpi.io>

readcloser.go

@@ -32,37 +32,38 @@ func (rc *ReadCloser) Read(b []byte) (int, error) {
 // remove it if it doesn't support Close() and fail
 // if closed twice
 func (rc *ReadCloser) Close() error {
-	switch p := rc.r.(type) {
-	case io.Closer:
-		return p.Close()
-	case nil:
-		return fs.ErrClosed
-	default:
+	switch {
+	case rc.r != nil:
 		rc.r = nil
 		return nil
+	default:
+		return fs.ErrClosed
 	}
 }
 
 // NewReadCloser wraps a [io.Reader] to satisfy
-// [io.ReadCloser]
-func NewReadCloser(r io.Reader) *ReadCloser {
-	if r == nil {
+// [io.ReadCloser] if needed
+func NewReadCloser(r io.Reader) io.ReadCloser {
+	switch p := r.(type) {
+	case io.ReadCloser:
+		return p
+	case nil:
 		return nil
-	}
-
-	return &ReadCloser{
-		r: r,
+	default:
+		return &ReadCloser{
+			r: r,
+		}
 	}
 }
 
 // NewReadCloserBytes wraps a bytes slice to implement
 // a [io.ReadCloser]
-func NewReadCloserBytes(b []byte) *ReadCloser {
+func NewReadCloserBytes(b []byte) io.ReadCloser {
 	return NewReadCloser(bytes.NewReader(b))
 }
 
 // NewReadCloserString wraps a string to implement
 // a [io.ReadCloser]
-func NewReadCloserString(s string) *ReadCloser {
+func NewReadCloserString(s string) io.ReadCloser {
 	return NewReadCloser(strings.NewReader(s))
 }