Dump: add output format tar and output to stdout (#10376)

* Dump: Use mholt/archive/v3 to support tar including many compressions

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Allow dump output to stdout

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: Fixed bug present since #6677 where SessionConfig.Provider is never "file"

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never pack RepoRootPath, LFS.ContentPath and LogRootPath when they are below AppDataPath

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: also dump LFS (fixes #10058)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Dump: never dump CustomPath if CustomPath is a subdir of or equal to AppDataPath (fixes #10365)

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* Use log.Info instead of fmt.Fprintf

Signed-off-by: Philipp Homann <homann.philipp@googlemail.com>

* import ordering

* make fmt

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Matti R <matti@mdranta.net>

vendor/github.com/mholt/archiver/v3/tarsz.go

@@ -0,0 +1,114 @@
+package archiver
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/golang/snappy"
+)
+
+// TarSz facilitates Snappy compression
+// (https://github.com/google/snappy)
+// of tarball archives.
+type TarSz struct {
+	*Tar
+}
+
+// CheckExt ensures the file extension matches the format.
+func (*TarSz) CheckExt(filename string) error {
+	if !strings.HasSuffix(filename, ".tar.sz") &&
+		!strings.HasSuffix(filename, ".tsz") {
+		return fmt.Errorf("filename must have a .tar.sz or .tsz extension")
+	}
+	return nil
+}
+
+// Archive creates a compressed tar file at destination
+// containing the files listed in sources. The destination
+// must end with ".tar.sz" or ".tsz". File paths can be
+// those of regular files or directories; directories will
+// be recursively added.
+func (tsz *TarSz) Archive(sources []string, destination string) error {
+	err := tsz.CheckExt(destination)
+	if err != nil {
+		return fmt.Errorf("output %s", err.Error())
+	}
+	tsz.wrapWriter()
+	return tsz.Tar.Archive(sources, destination)
+}
+
+// Unarchive unpacks the compressed tarball at
+// source to destination. Destination will be
+// treated as a folder name.
+func (tsz *TarSz) Unarchive(source, destination string) error {
+	tsz.wrapReader()
+	return tsz.Tar.Unarchive(source, destination)
+}
+
+// Walk calls walkFn for each visited item in archive.
+func (tsz *TarSz) Walk(archive string, walkFn WalkFunc) error {
+	tsz.wrapReader()
+	return tsz.Tar.Walk(archive, walkFn)
+}
+
+// Create opens tsz for writing a compressed
+// tar archive to out.
+func (tsz *TarSz) Create(out io.Writer) error {
+	tsz.wrapWriter()
+	return tsz.Tar.Create(out)
+}
+
+// Open opens t for reading a compressed archive from
+// in. The size parameter is not used.
+func (tsz *TarSz) Open(in io.Reader, size int64) error {
+	tsz.wrapReader()
+	return tsz.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 (tsz *TarSz) Extract(source, target, destination string) error {
+	tsz.wrapReader()
+	return tsz.Tar.Extract(source, target, destination)
+}
+
+func (tsz *TarSz) wrapWriter() {
+	var sw *snappy.Writer
+	tsz.Tar.writerWrapFn = func(w io.Writer) (io.Writer, error) {
+		sw = snappy.NewWriter(w)
+		return sw, nil
+	}
+	tsz.Tar.cleanupWrapFn = func() {
+		sw.Close()
+	}
+}
+
+func (tsz *TarSz) wrapReader() {
+	tsz.Tar.readerWrapFn = func(r io.Reader) (io.Reader, error) {
+		return snappy.NewReader(r), nil
+	}
+}
+
+func (tsz *TarSz) String() string { return "tar.sz" }
+
+// NewTarSz returns a new, default instance ready to be customized and used.
+func NewTarSz() *TarSz {
+	return &TarSz{
+		Tar: NewTar(),
+	}
+}
+
+// Compile-time checks to ensure type implements desired interfaces.
+var (
+	_ = Reader(new(TarSz))
+	_ = Writer(new(TarSz))
+	_ = Archiver(new(TarSz))
+	_ = Unarchiver(new(TarSz))
+	_ = Walker(new(TarSz))
+	_ = Extractor(new(TarSz))
+)
+
+// DefaultTarSz is a convenient archiver ready to use.
+var DefaultTarSz = NewTarSz()