1 files changed, 40 insertions, 27 deletions

diff --git a/pkg/archive.go b/pkg/archive.go
index e9f76f5b..ba7c61b9 100644
--- a/pkg/archive.go
+++ b/pkg/archive.go
@@ -314,36 +314,25 @@ func (archiveArtifact) IsExclusive() bool { return false }
 // Revision satisfies [RevisionArtifact] for status behaviour.
 func (archiveArtifact) Revision() uint64 { return 0 }
 
-// Cure cures the [Artifact], producing a directory located at work.
-func (a archiveArtifact) Cure(t *TContext) (err error) {
-	var status io.Writer
-	if status, err = t.GetStatusWriter(); err != nil {
-		return
-	}
-
-	var r io.ReadCloser
-	if r, err = t.Open(a.f); err != nil {
-		return
-	}
-
-	defer func() {
-		closeErr := r.Close()
-		if err == nil {
-			err = closeErr
-		}
-	}()
-
+// Extract reads an archive stream from r and writes its contents to dir. If
+// writeStatus is non-nil, it is called with a user-facing message after
+// each successfully extracted entry.
+func Extract(
+	r io.Reader,
+	dir string,
+	writeStatus func(s string) error,
+) (err error) {
 	type dirTargetPerm struct {
 		path string
 		mode fs.FileMode
 	}
 	var madeDirectories []dirTargetPerm
 
-	if err = os.MkdirAll(t.GetWorkDir().String(), 0700); err != nil {
+	if err = os.MkdirAll(dir, 0700); err != nil {
 		return
 	}
 	var root *os.Root
-	if root, err = os.OpenRoot(t.GetWorkDir().String()); err != nil {
+	if root, err = os.OpenRoot(dir); err != nil {
 		return
 	}
 	defer func() {
@@ -355,7 +344,6 @@ func (a archiveArtifact) Cure(t *TContext) (err error) {
 
 	var header *ArchiveHeader
 	ar := NewReader(r)
-	msg := t.GetMessage()
 	for header, err = ar.Next(); err == nil; header, err = ar.Next() {
 		var m string
 		if header.Mode.IsRegular() {
@@ -422,11 +410,8 @@ func (a archiveArtifact) Cure(t *TContext) (err error) {
 			return InvalidFileModeError(header.Mode)
 		}
 
-		if m != "" {
-			msg.Verbose(m)
-			if _, err = io.WriteString(status, m); err != nil {
-				return
-			} else if _, err = status.Write([]byte{'\n'}); err != nil {
+		if writeStatus != nil && m != "" {
+			if err = writeStatus(m); err != nil {
 				return
 			}
 		}
@@ -446,6 +431,34 @@ func (a archiveArtifact) Cure(t *TContext) (err error) {
 	return
 }
 
+// Cure cures the [Artifact], producing a directory located at work.
+func (a archiveArtifact) Cure(t *TContext) (err error) {
+	var status io.Writer
+	if status, err = t.GetStatusWriter(); err != nil {
+		return
+	}
+
+	var r io.ReadCloser
+	if r, err = t.Open(a.f); err != nil {
+		return
+	}
+
+	msg := t.GetMessage()
+	err = Extract(r, t.GetWorkDir().String(), func(s string) (err error) {
+		msg.Verbose(s)
+		if _, err = io.WriteString(status, s); err != nil {
+			return
+		}
+		_, err = status.Write([]byte{'\n'})
+		return
+	})
+
+	if closeErr := r.Close(); err == nil {
+		err = closeErr
+	}
+	return
+}
+
 // CuresExempt exempts the cheap [KindArchive] implementation often found at
 // the end of a [FileArtifact] pipeline.
 func (archiveArtifact) CuresExempt() {}