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/reader.go

@@ -0,0 +1,100 @@
+// 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 supports the decoding and encoding of LZMA streams.
+// Reader and Writer support the classic LZMA format. Reader2 and
+// Writer2 support the decoding and encoding of LZMA2 streams.
+//
+// The package is written completely in Go and doesn't rely on any external
+// library.
+package lzma
+
+import (
+	"errors"
+	"io"
+)
+
+// ReaderConfig stores the parameters for the reader of the classic LZMA
+// format.
+type ReaderConfig struct {
+	DictCap int
+}
+
+// fill converts the zero values of the configuration to the default values.
+func (c *ReaderConfig) fill() {
+	if c.DictCap == 0 {
+		c.DictCap = 8 * 1024 * 1024
+	}
+}
+
+// Verify checks the reader configuration for errors. Zero values will
+// be replaced by default values.
+func (c *ReaderConfig) Verify() error {
+	c.fill()
+	if !(MinDictCap <= c.DictCap && int64(c.DictCap) <= MaxDictCap) {
+		return errors.New("lzma: dictionary capacity is out of range")
+	}
+	return nil
+}
+
+// Reader provides a reader for LZMA files or streams.
+type Reader struct {
+	lzma io.Reader
+	h    header
+	d    *decoder
+}
+
+// NewReader creates a new reader for an LZMA stream using the classic
+// format. NewReader reads and checks the header of the LZMA stream.
+func NewReader(lzma io.Reader) (r *Reader, err error) {
+	return ReaderConfig{}.NewReader(lzma)
+}
+
+// NewReader creates a new reader for an LZMA stream in the classic
+// format. The function reads and verifies the the header of the LZMA
+// stream.
+func (c ReaderConfig) NewReader(lzma io.Reader) (r *Reader, err error) {
+	if err = c.Verify(); err != nil {
+		return nil, err
+	}
+	data := make([]byte, HeaderLen)
+	if _, err := io.ReadFull(lzma, data); err != nil {
+		if err == io.EOF {
+			return nil, errors.New("lzma: unexpected EOF")
+		}
+		return nil, err
+	}
+	r = &Reader{lzma: lzma}
+	if err = r.h.unmarshalBinary(data); err != nil {
+		return nil, err
+	}
+	if r.h.dictCap < MinDictCap {
+		return nil, errors.New("lzma: dictionary capacity too small")
+	}
+	dictCap := r.h.dictCap
+	if c.DictCap > dictCap {
+		dictCap = c.DictCap
+	}
+
+	state := newState(r.h.properties)
+	dict, err := newDecoderDict(dictCap)
+	if err != nil {
+		return nil, err
+	}
+	r.d, err = newDecoder(ByteReader(lzma), state, dict, r.h.size)
+	if err != nil {
+		return nil, err
+	}
+	return r, nil
+}
+
+// EOSMarker indicates that an EOS marker has been encountered.
+func (r *Reader) EOSMarker() bool {
+	return r.d.eosMarker
+}
+
+// Read returns uncompressed data.
+func (r *Reader) Read(p []byte) (n int, err error) {
+	return r.d.Read(p)
+}