tarfs: remove ReadFile

Signed-off-by: Brad Lugo <blugo@redhat.com>

Author: BradLugo

pkg/tarfs/tarfs.go

@@ -452,51 +452,6 @@ func (f *FS) ReadDir(name string) ([]fs.DirEntry, error) {
 	return ret, nil
 }
 
-// ReadFile implements fs.ReadFileFS.
-func (f *FS) ReadFile(name string) ([]byte, error) {
-	// ReadFileFS is implemented because it can avoid allocating an intermediate
-	// "file" struct and can immediately allocate a byte slice of the correct
-	// size.
-	const op = `readfile`
-	i, err := f.getInode(op, name)
-	if err != nil {
-		return nil, err
-	}
-
-	dataSize := i.h.Size
-	typ := i.h.FileInfo().Mode().Type()
-	var r *tar.Reader
-	switch {
-	case typ.IsRegular() && i.h.Typeflag != tar.TypeLink:
-		r = tar.NewReader(io.NewSectionReader(f.r, i.off, i.sz))
-	case typ.IsRegular() && i.h.Typeflag == tar.TypeLink || typ&fs.ModeSymlink != 0: // is hardlink or symlink
-		return f.ReadFile(i.h.Linkname)
-	default:
-		// Pretend all other kinds of files don't exist.
-		return nil, &fs.PathError{
-			Op:   op,
-			Path: name,
-			Err:  fs.ErrExist,
-		}
-	}
-	if _, err := r.Next(); err != nil {
-		return nil, &fs.PathError{
-			Op:   op,
-			Path: name,
-			Err:  err,
-		}
-	}
-	ret := make([]byte, dataSize)
-	if _, err := io.ReadFull(r, ret); err != nil {
-		return nil, &fs.PathError{
-			Op:   op,
-			Path: name,
-			Err:  err,
-		}
-	}
-	return ret, nil
-}
-
 // Glob implements fs.GlobFS.
 //
 // See path.Match for the patten syntax.
@@ -548,10 +503,9 @@ func (f *FS) Sub(dir string) (fs.FS, error) {
 
 // A bunch of static assertions for the fs interfaces.
 var (
-	_ fs.FS         = (*FS)(nil)
-	_ fs.GlobFS     = (*FS)(nil)
-	_ fs.ReadDirFS  = (*FS)(nil)
-	_ fs.ReadFileFS = (*FS)(nil)
-	_ fs.StatFS     = (*FS)(nil)
-	_ fs.SubFS      = (*FS)(nil)
+	_ fs.FS        = (*FS)(nil)
+	_ fs.GlobFS    = (*FS)(nil)
+	_ fs.ReadDirFS = (*FS)(nil)
+	_ fs.StatFS    = (*FS)(nil)
+	_ fs.SubFS     = (*FS)(nil)
 )

pkg/tarfs/tarfs_test.go

@@ -460,83 +460,6 @@ func TestSymlinks(t *testing.T) {
 	}))
 }
 
-func TestReadFile(t *testing.T) {
-	type tarfsFile struct {
-		Header tar.Header
-		Data   []byte
-	}
-
-	tmp := t.TempDir()
-	setupAndRun := func(openErr bool, tarfsFiles []tarfsFile, chk func(*testing.T, *FS)) {
-		t.Helper()
-		// This is a perfect candidate for using test.GenerateFixture, but
-		// creates an import cycle.
-		f, err := os.Create(filepath.Join(tmp, filepath.Base(t.Name())))
-		if err != nil {
-			t.Fatal(err)
-		}
-		defer f.Close()
-
-		tw := tar.NewWriter(f)
-		for _, tarfsFile := range tarfsFiles {
-			h := tarfsFile.Header
-			h.Size = int64(len(tarfsFile.Data))
-			h.Format = tar.FormatGNU
-			if err := tw.WriteHeader(&h); err != nil {
-				t.Error(err)
-			}
-			_, err := tw.Write(tarfsFile.Data)
-			if err != nil {
-				t.Error(err)
-			}
-		}
-		if err := tw.Close(); err != nil {
-			t.Error(err)
-		}
-
-		sys, err := New(f)
-		t.Log(err)
-		if (err != nil) != openErr {
-			t.Fail()
-		}
-
-		if chk != nil {
-			chk(t, sys)
-		}
-	}
-
-	t.Run("Hardlink", func(t *testing.T) {
-		originalData := []byte(`Hello, World!`)
-		abData := make([]byte, len(originalData))
-		copy(abData, originalData)
-
-		setupAndRun(false, []tarfsFile{
-			{
-				Header: tar.Header{Name: `a/`},
-			},
-			{
-				Header: tar.Header{Name: `a/b`},
-				Data:   abData,
-			},
-			{
-				Header: tar.Header{
-					Name:     `a/c`,
-					Typeflag: tar.TypeLink,
-					Linkname: `a/b`,
-				},
-			},
-		}, func(t *testing.T, sys *FS) {
-			acFile, err := sys.ReadFile("a/c")
-			if err != nil {
-				t.Errorf("error while opening file: %v", err)
-			}
-			if !bytes.Equal(originalData, acFile) {
-				t.Errorf("unexpected \"%s\", got \"%s\"", originalData, acFile)
-			}
-		})
-	})
-}
-
 func TestKnownLayers(t *testing.T) {
 	ents, err := os.ReadDir(`testdata/known`)
 	if err != nil {