internal/pkg: remove tar built-in decompressor

This is replaced by decompressArtifact and is no longer necessary.

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

internal/pkg/tar.go

@@ -2,32 +2,18 @@ package pkg
 
 import (
 	"archive/tar"
-	"compress/bzip2"
-	"compress/gzip"
 	"errors"
 	"fmt"
 	"io"
 	"io/fs"
-	"net/http"
 	"os"
 	"path/filepath"
 )
 
-const (
-	// TarUncompressed denotes an uncompressed tarball.
-	TarUncompressed = iota
-	// TarGzip denotes a tarball compressed via [gzip].
-	TarGzip
-	// TarBzip2 denotes a tarball compressed via [bzip2].
-	TarBzip2
-)
-
 // A tarArtifact is an [Artifact] unpacking a tarball backed by a [FileArtifact].
 type tarArtifact struct {
 	// Caller-supplied backing tarball.
 	f Artifact
-	// Compression on top of the tarball.
-	compression uint32
 }
 
 // tarArtifactNamed embeds tarArtifact for a [fmt.Stringer] tarball.
@@ -42,10 +28,10 @@ var _ fmt.Stringer = new(tarArtifactNamed)
 // String returns the name of the underlying [Artifact] suffixed with unpack.
 func (a *tarArtifactNamed) String() string { return a.name + "-unpack" }
 
-// NewTar returns a new [Artifact] backed by the supplied [Artifact] and
-// compression method. The source [Artifact] must be a [FileArtifact].
-func NewTar(a Artifact, compression uint32) Artifact {
-	ta := tarArtifact{a, compression}
+// NewTar returns a new [Artifact] unpacking the tar stream produced by the
+// backing [Artifact]. The source [Artifact] must be a [FileArtifact].
+func NewTar(a Artifact) Artifact {
+	ta := tarArtifact{a}
 	if s, ok := a.(fmt.Stringer); ok {
 		if name := s.String(); name != "" {
 			return &tarArtifactNamed{ta, name}
@@ -54,25 +40,15 @@ func NewTar(a Artifact, compression uint32) Artifact {
 	return &ta
 }
 
-// NewHTTPGetTar is abbreviation for NewHTTPGet passed to NewTar.
-func NewHTTPGetTar(
-	hc *http.Client,
-	url string,
-	checksum Checksum,
-	compression uint32,
-) Artifact {
-	return NewTar(NewHTTPGet(hc, url, checksum), compression)
-}
-
 // Kind returns the hardcoded [Kind] constant.
 func (a *tarArtifact) Kind() Kind { return KindTar }
 
-// Params writes compression encoded in little endian.
-func (a *tarArtifact) Params(ctx *IContext) { ctx.WriteUint32(a.compression) }
+// Params is a noop.
+func (a *tarArtifact) Params(*IContext) {}
 
 func init() {
 	register(KindTar, func(r *IRReader) Artifact {
-		a := NewTar(r.Next(), r.ReadUint32())
+		a := NewTar(r.Next())
 		if _, ok := r.Finalise(); ok {
 			panic(ErrUnexpectedChecksum)
 		}
@@ -98,42 +74,17 @@ func (e DisallowedTypeflagError) Error() string {
 
 // Cure cures the [Artifact], producing a directory located at work.
 func (a *tarArtifact) Cure(t *TContext) (err error) {
-	var tr io.ReadCloser
-	if tr, err = t.Open(a.f); err != nil {
+	var r io.ReadCloser
+	if r, err = t.Open(a.f); err != nil {
 		return
 	}
 
-	defer func(f io.ReadCloser) {
-		if err == nil {
-			err = tr.Close()
-		}
-
-		closeErr := f.Close()
+	defer func() {
+		closeErr := r.Close()
 		if err == nil {
 			err = closeErr
 		}
-	}(tr)
-	br := t.cache.getReader(tr)
-	defer t.cache.putReader(br)
-	tr = io.NopCloser(br)
-
-	switch a.compression {
-	case TarUncompressed:
-		break
-
-	case TarGzip:
-		if tr, err = gzip.NewReader(tr); err != nil {
-			return
-		}
-		break
-
-	case TarBzip2:
-		tr = io.NopCloser(bzip2.NewReader(tr))
-		break
-
-	default:
-		return os.ErrInvalid
-	}
+	}()
 
 	type dirTargetPerm struct {
 		path string
@@ -156,8 +107,8 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 	}()
 
 	var header *tar.Header
-	r := tar.NewReader(tr)
-	for header, err = r.Next(); err == nil; header, err = r.Next() {
+	tr := tar.NewReader(r)
+	for header, err = tr.Next(); err == nil; header, err = tr.Next() {
 		typeflag := header.Typeflag
 		if typeflag == 0 {
 			if len(header.Name) > 0 && header.Name[len(header.Name)-1] == '/' {
@@ -183,7 +134,7 @@ func (a *tarArtifact) Cure(t *TContext) (err error) {
 			); err != nil {
 				return
 			}
-			if _, err = io.Copy(f, r); err != nil {
+			if _, err = io.Copy(f, tr); err != nil {
 				_ = f.Close()
 				return
 			} else if err = f.Close(); err != nil {