Adding upstream version 3.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

tarzst.go

@@ -0,0 +1,120 @@
+package archiver
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/klauspost/compress/zstd"
+)
+
+// TarZstd facilitates Zstandard compression
+// (RFC 8478) of tarball archives.
+type TarZstd struct {
+	*Tar
+}
+
+// CheckExt ensures the file extension matches the format.
+func (*TarZstd) CheckExt(filename string) error {
+	if !strings.HasSuffix(filename, ".tar.zst") {
+		return fmt.Errorf("filename must have a .tar.zst extension")
+	}
+	return nil
+}
+
+// Archive creates a compressed tar file at destination
+// containing the files listed in sources. The destination
+// must end with ".tar.zst" or ".tzst". File paths can be
+// those of regular files or directories; directories will
+// be recursively added.
+func (tzst *TarZstd) Archive(sources []string, destination string) error {
+	err := tzst.CheckExt(destination)
+	if err != nil {
+		return fmt.Errorf("output %s", err.Error())
+	}
+	tzst.wrapWriter()
+	return tzst.Tar.Archive(sources, destination)
+}
+
+// Unarchive unpacks the compressed tarball at
+// source to destination. Destination will be
+// treated as a folder name.
+func (tzst *TarZstd) Unarchive(source, destination string) error {
+	tzst.wrapReader()
+	return tzst.Tar.Unarchive(source, destination)
+}
+
+// Walk calls walkFn for each visited item in archive.
+func (tzst *TarZstd) Walk(archive string, walkFn WalkFunc) error {
+	tzst.wrapReader()
+	return tzst.Tar.Walk(archive, walkFn)
+}
+
+// Create opens txz for writing a compressed
+// tar archive to out.
+func (tzst *TarZstd) Create(out io.Writer) error {
+	tzst.wrapWriter()
+	return tzst.Tar.Create(out)
+}
+
+// Open opens t for reading a compressed archive from
+// in. The size parameter is not used.
+func (tzst *TarZstd) Open(in io.Reader, size int64) error {
+	tzst.wrapReader()
+	return tzst.Tar.Open(in, size)
+}
+
+// Extract extracts a single file from the tar archive.
+// If the target is a directory, the entire folder will
+// be extracted into destination.
+func (tzst *TarZstd) Extract(source, target, destination string) error {
+	tzst.wrapReader()
+	return tzst.Tar.Extract(source, target, destination)
+}
+
+func (tzst *TarZstd) wrapWriter() {
+	var zstdw *zstd.Encoder
+	tzst.Tar.writerWrapFn = func(w io.Writer) (io.Writer, error) {
+		var err error
+		zstdw, err = zstd.NewWriter(w)
+		return zstdw, err
+	}
+	tzst.Tar.cleanupWrapFn = func() {
+		zstdw.Close()
+	}
+}
+
+func (tzst *TarZstd) wrapReader() {
+	var zstdr *zstd.Decoder
+	tzst.Tar.readerWrapFn = func(r io.Reader) (io.Reader, error) {
+		var err error
+		zstdr, err = zstd.NewReader(r)
+		return zstdr, err
+	}
+	tzst.Tar.cleanupWrapFn = func() {
+		zstdr.Close()
+	}
+}
+
+func (tzst *TarZstd) String() string { return "tar.zst" }
+
+// NewTarZstd returns a new, default instance ready to be customized and used.
+func NewTarZstd() *TarZstd {
+	return &TarZstd{
+		Tar: NewTar(),
+	}
+}
+
+// Compile-time checks to ensure type implements desired interfaces.
+var (
+	_ = Reader(new(TarZstd))
+	_ = Writer(new(TarZstd))
+	_ = Archiver(new(TarZstd))
+	_ = Unarchiver(new(TarZstd))
+	_ = Walker(new(TarZstd))
+	_ = ExtensionChecker(new(TarZstd))
+	_ = Extractor(new(TarZstd))
+)
+
+// DefaultTarZstd is a convenient archiver ready to use.
+var DefaultTarZstd = NewTarZstd()