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/ulikunitz/xz/lzma/operation.go

@@ -0,0 +1,80 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+import (
+	"errors"
+	"fmt"
+	"unicode"
+)
+
+// operation represents an operation on the dictionary during encoding or
+// decoding.
+type operation interface {
+	Len() int
+}
+
+// rep represents a repetition at the given distance and the given length
+type match struct {
+	// supports all possible distance values, including the eos marker
+	distance int64
+	// length
+	n int
+}
+
+// verify checks whether the match is valid. If that is not the case an
+// error is returned.
+func (m match) verify() error {
+	if !(minDistance <= m.distance && m.distance <= maxDistance) {
+		return errors.New("distance out of range")
+	}
+	if !(1 <= m.n && m.n <= maxMatchLen) {
+		return errors.New("length out of range")
+	}
+	return nil
+}
+
+// l return the l-value for the match, which is the difference of length
+// n and 2.
+func (m match) l() uint32 {
+	return uint32(m.n - minMatchLen)
+}
+
+// dist returns the dist value for the match, which is one less of the
+// distance stored in the match.
+func (m match) dist() uint32 {
+	return uint32(m.distance - minDistance)
+}
+
+// Len returns the number of bytes matched.
+func (m match) Len() int {
+	return m.n
+}
+
+// String returns a string representation for the repetition.
+func (m match) String() string {
+	return fmt.Sprintf("M{%d,%d}", m.distance, m.n)
+}
+
+// lit represents a single byte literal.
+type lit struct {
+	b byte
+}
+
+// Len returns 1 for the single byte literal.
+func (l lit) Len() int {
+	return 1
+}
+
+// String returns a string representation for the literal.
+func (l lit) String() string {
+	var c byte
+	if unicode.IsPrint(rune(l.b)) {
+		c = l.b
+	} else {
+		c = '.'
+	}
+	return fmt.Sprintf("L{%c/%02x}", c, l.b)
+}