diff options
Diffstat (limited to 'vendor/github.com/vbatts/tar-split/tar/storage/packer.go')
-rw-r--r-- | vendor/github.com/vbatts/tar-split/tar/storage/packer.go | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/vendor/github.com/vbatts/tar-split/tar/storage/packer.go b/vendor/github.com/vbatts/tar-split/tar/storage/packer.go new file mode 100644 index 000000000..aba694818 --- /dev/null +++ b/vendor/github.com/vbatts/tar-split/tar/storage/packer.go @@ -0,0 +1,127 @@ +package storage + +import ( + "encoding/json" + "errors" + "io" + "path/filepath" + "unicode/utf8" +) + +// ErrDuplicatePath occurs when a tar archive has more than one entry for the +// same file path +var ErrDuplicatePath = errors.New("duplicates of file paths not supported") + +// Packer describes the methods to pack Entries to a storage destination +type Packer interface { + // AddEntry packs the Entry and returns its position + AddEntry(e Entry) (int, error) +} + +// Unpacker describes the methods to read Entries from a source +type Unpacker interface { + // Next returns the next Entry being unpacked, or error, until io.EOF + Next() (*Entry, error) +} + +/* TODO(vbatts) figure out a good model for this +type PackUnpacker interface { + Packer + Unpacker +} +*/ + +type jsonUnpacker struct { + seen seenNames + dec *json.Decoder +} + +func (jup *jsonUnpacker) Next() (*Entry, error) { + var e Entry + err := jup.dec.Decode(&e) + if err != nil { + return nil, err + } + + // check for dup name + if e.Type == FileType { + cName := filepath.Clean(e.GetName()) + if _, ok := jup.seen[cName]; ok { + return nil, ErrDuplicatePath + } + jup.seen[cName] = struct{}{} + } + + return &e, err +} + +// NewJSONUnpacker provides an Unpacker that reads Entries (SegmentType and +// FileType) as a json document. +// +// Each Entry read are expected to be delimited by new line. +func NewJSONUnpacker(r io.Reader) Unpacker { + return &jsonUnpacker{ + dec: json.NewDecoder(r), + seen: seenNames{}, + } +} + +type jsonPacker struct { + w io.Writer + e *json.Encoder + pos int + seen seenNames +} + +type seenNames map[string]struct{} + +func (jp *jsonPacker) AddEntry(e Entry) (int, error) { + // if Name is not valid utf8, switch it to raw first. + if e.Name != "" { + if !utf8.ValidString(e.Name) { + e.NameRaw = []byte(e.Name) + e.Name = "" + } + } + + // check early for dup name + if e.Type == FileType { + cName := filepath.Clean(e.GetName()) + if _, ok := jp.seen[cName]; ok { + return -1, ErrDuplicatePath + } + jp.seen[cName] = struct{}{} + } + + e.Position = jp.pos + err := jp.e.Encode(e) + if err != nil { + return -1, err + } + + // made it this far, increment now + jp.pos++ + return e.Position, nil +} + +// NewJSONPacker provides a Packer that writes each Entry (SegmentType and +// FileType) as a json document. +// +// The Entries are delimited by new line. +func NewJSONPacker(w io.Writer) Packer { + return &jsonPacker{ + w: w, + e: json.NewEncoder(w), + seen: seenNames{}, + } +} + +/* +TODO(vbatts) perhaps have a more compact packer/unpacker, maybe using msgapck +(https://github.com/ugorji/go) + + +Even though, since our jsonUnpacker and jsonPacker just take +io.Reader/io.Writer, then we can get away with passing them a +gzip.Reader/gzip.Writer +*/ |