forked from mirrors/tar-split
88 lines
1.7 KiB
Go
88 lines
1.7 KiB
Go
package storage
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import (
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"bufio"
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"encoding/json"
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"io"
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)
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type Packer interface {
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// AddSegment packs the segment bytes provided and returns the position of
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// the entry
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//AddSegment([]byte) (int, error)
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// AddFile packs the File provided and returns the position of the entry. The
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// Position is set in the stored File.
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//AddFile(File) (int, error)
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//
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AddEntry(e Entry) (int, error)
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}
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type Unpacker interface {
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Next() (*Entry, error)
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}
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type PackUnpacker interface {
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Packer
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Unpacker
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}
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type jsonUnpacker struct {
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r io.Reader
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b *bufio.Reader
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isEOF bool
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}
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func (jup *jsonUnpacker) Next() (*Entry, error) {
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var e Entry
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if jup.isEOF {
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// since ReadBytes() will return read bytes AND an EOF, we handle it this
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// round-a-bout way so we can Unmarshal the tail with relevant errors, but
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// still get an io.EOF when the stream is ended.
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return nil, io.EOF
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}
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line, err := jup.b.ReadBytes('\n')
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if err != nil && err != io.EOF {
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return nil, err
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} else if err == io.EOF {
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jup.isEOF = true
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}
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err = json.Unmarshal(line, &e)
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if err != nil && jup.isEOF {
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// if the remainder actually _wasn't_ a remaining json structure, then just EOF
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return nil, io.EOF
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}
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return &e, err
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}
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// jsonUnpacker writes each entry (SegmentType and FileType) as a json document.
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// Each entry on a new line.
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func NewJsonUnpacker(r io.Reader) Unpacker {
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return &jsonUnpacker{
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r: r,
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b: bufio.NewReader(r),
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}
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}
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type jsonPacker struct {
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w io.Writer
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e *json.Encoder
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pos int
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}
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func (jp *jsonPacker) AddEntry(e Entry) (int, error) {
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e.Position = jp.pos
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err := jp.e.Encode(e)
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if err == nil {
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jp.pos++
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}
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return e.Position, err
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}
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func NewJsonPacker(w io.Writer) Packer {
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return &jsonPacker{
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w: w,
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e: json.NewEncoder(w),
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}
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}
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