1package archiver
2
3import (
4	"fmt"
5	"io"
6	"strings"
7
8	"github.com/dsnet/compress/bzip2"
9)
10
11// TarBz2 facilitates bzip2 compression
12// (https://github.com/dsnet/compress/blob/master/doc/bzip2-format.pdf)
13// of tarball archives.
14type TarBz2 struct {
15	*Tar
16
17	CompressionLevel int
18}
19
20// CheckExt ensures the file extension matches the format.
21func (*TarBz2) CheckExt(filename string) error {
22	if !strings.HasSuffix(filename, ".tar.bz2") &&
23		!strings.HasSuffix(filename, ".tbz2") {
24		return fmt.Errorf("filename must have a .tar.bz2 or .tbz2 extension")
25	}
26	return nil
27}
28
29// Archive creates a compressed tar file at destination
30// containing the files listed in sources. The destination
31// must end with ".tar.bz2" or ".tbz2". File paths can be
32// those of regular files or directories; directories will
33// be recursively added.
34func (tbz2 *TarBz2) Archive(sources []string, destination string) error {
35	err := tbz2.CheckExt(destination)
36	if err != nil {
37		return fmt.Errorf("output %s", err.Error())
38	}
39	tbz2.wrapWriter()
40	return tbz2.Tar.Archive(sources, destination)
41}
42
43// Unarchive unpacks the compressed tarball at
44// source to destination. Destination will be
45// treated as a folder name.
46func (tbz2 *TarBz2) Unarchive(source, destination string) error {
47	tbz2.wrapReader()
48	return tbz2.Tar.Unarchive(source, destination)
49}
50
51// Walk calls walkFn for each visited item in archive.
52func (tbz2 *TarBz2) Walk(archive string, walkFn WalkFunc) error {
53	tbz2.wrapReader()
54	return tbz2.Tar.Walk(archive, walkFn)
55}
56
57// Create opens tbz2 for writing a compressed
58// tar archive to out.
59func (tbz2 *TarBz2) Create(out io.Writer) error {
60	tbz2.wrapWriter()
61	return tbz2.Tar.Create(out)
62}
63
64// Open opens t for reading a compressed archive from
65// in. The size parameter is not used.
66func (tbz2 *TarBz2) Open(in io.Reader, size int64) error {
67	tbz2.wrapReader()
68	return tbz2.Tar.Open(in, size)
69}
70
71// Extract extracts a single file from the tar archive.
72// If the target is a directory, the entire folder will
73// be extracted into destination.
74func (tbz2 *TarBz2) Extract(source, target, destination string) error {
75	tbz2.wrapReader()
76	return tbz2.Tar.Extract(source, target, destination)
77}
78
79func (tbz2 *TarBz2) wrapWriter() {
80	var bz2w *bzip2.Writer
81	tbz2.Tar.writerWrapFn = func(w io.Writer) (io.Writer, error) {
82		var err error
83		bz2w, err = bzip2.NewWriter(w, &bzip2.WriterConfig{
84			Level: tbz2.CompressionLevel,
85		})
86		return bz2w, err
87	}
88	tbz2.Tar.cleanupWrapFn = func() {
89		bz2w.Close()
90	}
91}
92
93func (tbz2 *TarBz2) wrapReader() {
94	var bz2r *bzip2.Reader
95	tbz2.Tar.readerWrapFn = func(r io.Reader) (io.Reader, error) {
96		var err error
97		bz2r, err = bzip2.NewReader(r, nil)
98		return bz2r, err
99	}
100	tbz2.Tar.cleanupWrapFn = func() {
101		bz2r.Close()
102	}
103}
104
105func (tbz2 *TarBz2) String() string { return "tar.bz2" }
106
107// NewTarBz2 returns a new, default instance ready to be customized and used.
108func NewTarBz2() *TarBz2 {
109	return &TarBz2{
110		CompressionLevel: bzip2.DefaultCompression,
111		Tar:              NewTar(),
112	}
113}
114
115// Compile-time checks to ensure type implements desired interfaces.
116var (
117	_ = Reader(new(TarBz2))
118	_ = Writer(new(TarBz2))
119	_ = Archiver(new(TarBz2))
120	_ = Unarchiver(new(TarBz2))
121	_ = Walker(new(TarBz2))
122	_ = Extractor(new(TarBz2))
123)
124
125// DefaultTarBz2 is a convenient archiver ready to use.
126var DefaultTarBz2 = NewTarBz2()
127