pkg: write tar status

This serves as a status indicator while fetching large tarballs, and
preserves information otherwise stripped during unpacking. This is a
revision of the tarArtifact to avoid inconsistent state from previously
cured tarArtifact lacking their status files.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 52 insertions, 5 deletions

diff --git a/pkg/tar.go b/pkg/tar.go
index 9a8c4b76..33952b05 100644
--- a/pkg/tar.go
+++ b/pkg/tar.go
@@ -66,6 +66,9 @@ func (a *tarArtifact) Inputs() []Artifact {
 // IsExclusive returns false: decompressor and tar reader are fully sequential.
 func (a *tarArtifact) IsExclusive() bool { return false }
 
+// Revision satisfies [RevisionArtifact] for status behaviour.
+func (*tarArtifact) Revision() uint64 { return 0 }
+
 // A DisallowedTypeflagError describes a disallowed typeflag encountered while
 // unpacking a tarball.
 type DisallowedTypeflagError byte
@@ -76,6 +79,11 @@ func (e DisallowedTypeflagError) Error() string {
 
 // Cure cures the [Artifact], producing a directory located at work.
 func (a *tarArtifact) 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
@@ -110,6 +118,7 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 
 	var header *tar.Header
 	tr := tar.NewReader(r)
+	msg := t.GetMessage()
 	for header, err = tr.Next(); err == nil; header, err = tr.Next() {
 		typeflag := header.Typeflag
 		if typeflag == 0 {
@@ -126,6 +135,7 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			}
 		}
 
+		var m string
 		switch typeflag {
 		case tar.TypeReg:
 			var f *os.File
@@ -142,6 +152,13 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			} else if err = f.Close(); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s (%d bytes)",
+				header.FileInfo().Mode(),
+				header.Name,
+				header.Size,
+			)
 			break
 
 		case tar.TypeLink:
@@ -151,6 +168,13 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s linkname %s",
+				header.FileInfo().Mode(),
+				header.Name,
+				header.Linkname,
+			)
 			break
 
 		case tar.TypeSymlink:
@@ -160,6 +184,13 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s linkname %s",
+				header.FileInfo().Mode(),
+				header.Name,
+				header.Linkname,
+			)
 			break
 
 		case tar.TypeDir:
@@ -170,21 +201,37 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			if err = root.MkdirAll(header.Name, 0700); err != nil {
 				return
 			}
+
+			m = fmt.Sprintf(
+				"%s %s",
+				header.FileInfo().Mode(),
+				header.Name,
+			)
 			break
 
 		case tar.TypeChar:
-			t.GetMessage().Verbosef(
-				"%sskipping character device %d, %d %q%s",
-				t.cache.sgrWarn, header.Devmajor, header.Devminor, header.Name, t.cache.sgrRes,
+			m = fmt.Sprintf(
+				"skipping character device %d, %d %q",
+				header.Devmajor, header.Devminor, header.Name,
 			)
-			continue
+			break
 
 		case tar.TypeXGlobalHeader:
-			continue // ignore
+			m = "skipping PAX global key-value record"
+			break
 
 		default:
 			return DisallowedTypeflagError(typeflag)
 		}
+
+		if m != "" {
+			msg.Verbose(m)
+			if _, err = io.WriteString(status, m); err != nil {
+				return
+			} else if _, err = status.Write([]byte{'\n'}); err != nil {
+				return
+			}
+		}
 	}
 	if errors.Is(err, io.EOF) {
 		err = nil