new chunk interface

chunk.go

// Split(ctx context.Context, data io.Reader, put func([]byte) Chunk) (Key, <-chan struct{}, err)
// Join(hash []byte, get func(Key)) LazySectionReader
// LazySectionReader should implement the WriterTo interface

type Context {
  Done() <-chan struct{}
  Err() error
}

const (
  Created int = iota
  Fetching
  Available
  Unavailable
  Stored
  Unstoreable
)

type Chunk interface {
Data() Data
Addr() Key
Ready() Context
Stored() Context
}

type ChunkFetcher interface {
Fetch(ctx context.Context)
}

type Data interface {
  Span() int64
  Length() int
  Bytes() []byte
}

type SegmentWriter interface {
  Write(int, []byte)
}

func IsAvailable(c Chunk) (bool, err){
  ctx := c.Ready()
  if ctx == nil {
    return true, nil
  }
  select {
  case ctx.Done():
    return true, ctx.Err()
  default:
    return false, nil
  }
}

func IsStored(c Chunk) (bool, err) {
  ctx := c.Store()
  if ctx == nil {
    return true, nil
  }
  select {
  case ctx.Done():
    return true, ctx.Err()
  default:
    return false, nil
  }
}

func State(c Chunk) int {

}


- created
- fetching
- ready
- unavailable
- stored
- not-stored