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.NewBufferedWriter(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()