Adding upstream version 3.5.1.

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

targz.go

@@ -0,0 +1,137 @@
+package archiver
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/klauspost/compress/gzip"
+	"github.com/klauspost/pgzip"
+)
+
+// TarGz facilitates gzip compression
+// (RFC 1952) of tarball archives.
+type TarGz struct {
+	*Tar
+
+	// The compression level to use, as described
+	// in the compress/gzip package.
+	CompressionLevel int
+
+	// Disables parallel gzip.
+	SingleThreaded bool
+}
+
+// CheckExt ensures the file extension matches the format.
+func (*TarGz) CheckExt(filename string) error {
+	if !strings.HasSuffix(filename, ".tar.gz") &&
+		!strings.HasSuffix(filename, ".tgz") {
+		return fmt.Errorf("filename must have a .tar.gz or .tgz extension")
+	}
+	return nil
+}
+
+// Archive creates a compressed tar file at destination
+// containing the files listed in sources. The destination
+// must end with ".tar.gz" or ".tgz". File paths can be
+// those of regular files or directories; directories will
+// be recursively added.
+func (tgz *TarGz) Archive(sources []string, destination string) error {
+	err := tgz.CheckExt(destination)
+	if err != nil {
+		return fmt.Errorf("output %s", err.Error())
+	}
+	tgz.wrapWriter()
+	return tgz.Tar.Archive(sources, destination)
+}
+
+// Unarchive unpacks the compressed tarball at
+// source to destination. Destination will be
+// treated as a folder name.
+func (tgz *TarGz) Unarchive(source, destination string) error {
+	tgz.wrapReader()
+	return tgz.Tar.Unarchive(source, destination)
+}
+
+// Walk calls walkFn for each visited item in archive.
+func (tgz *TarGz) Walk(archive string, walkFn WalkFunc) error {
+	tgz.wrapReader()
+	return tgz.Tar.Walk(archive, walkFn)
+}
+
+// Create opens txz for writing a compressed
+// tar archive to out.
+func (tgz *TarGz) Create(out io.Writer) error {
+	tgz.wrapWriter()
+	return tgz.Tar.Create(out)
+}
+
+// Open opens t for reading a compressed archive from
+// in. The size parameter is not used.
+func (tgz *TarGz) Open(in io.Reader, size int64) error {
+	tgz.wrapReader()
+	return tgz.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 (tgz *TarGz) Extract(source, target, destination string) error {
+	tgz.wrapReader()
+	return tgz.Tar.Extract(source, target, destination)
+}
+
+func (tgz *TarGz) wrapWriter() {
+	var gzw io.WriteCloser
+	tgz.Tar.writerWrapFn = func(w io.Writer) (io.Writer, error) {
+		var err error
+		if tgz.SingleThreaded {
+			gzw, err = gzip.NewWriterLevel(w, tgz.CompressionLevel)
+		} else {
+			gzw, err = pgzip.NewWriterLevel(w, tgz.CompressionLevel)
+		}
+		return gzw, err
+	}
+	tgz.Tar.cleanupWrapFn = func() {
+		gzw.Close()
+	}
+}
+
+func (tgz *TarGz) wrapReader() {
+	var gzr io.ReadCloser
+	tgz.Tar.readerWrapFn = func(r io.Reader) (io.Reader, error) {
+		var err error
+		if tgz.SingleThreaded {
+			gzr, err = gzip.NewReader(r)
+		} else {
+			gzr, err = pgzip.NewReader(r)
+		}
+		return gzr, err
+	}
+	tgz.Tar.cleanupWrapFn = func() {
+		gzr.Close()
+	}
+}
+
+func (tgz *TarGz) String() string { return "tar.gz" }
+
+// NewTarGz returns a new, default instance ready to be customized and used.
+func NewTarGz() *TarGz {
+	return &TarGz{
+		CompressionLevel: gzip.DefaultCompression,
+		Tar:              NewTar(),
+	}
+}
+
+// Compile-time checks to ensure type implements desired interfaces.
+var (
+	_ = Reader(new(TarGz))
+	_ = Writer(new(TarGz))
+	_ = Archiver(new(TarGz))
+	_ = Unarchiver(new(TarGz))
+	_ = Walker(new(TarGz))
+	_ = Extractor(new(TarGz))
+)
+
+// DefaultTarGz is a convenient archiver ready to use.
+var DefaultTarGz = NewTarGz()