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package main
import (
"bufio"
"bytes"
"fmt"
"io"
"log"
"os"
"path"
)
type ChunkId struct {
Ver int
Idx uint64
}
func (i *ChunkId) Reader(repo string) ChunkReader {
p := path.Join(repo, fmt.Sprintf(versionFmt, i.Ver), chunksName, fmt.Sprintf(chunkIdFmt, i.Idx))
f, err := os.Open(p)
if err != nil {
log.Printf("Cannot open chunk %s\n", p)
}
return bufio.NewReaderSize(f, chunkSize)
}
type ChunkReader interface {
io.Reader
io.ByteReader
}
type Chunk struct {
Repo *Repo
Id *ChunkId
Value []byte
}
func (c *Chunk) Read(buff []byte) (int, error) {
r, err := c.Reader()
if err != nil {
return 0, err
}
return r.Read(buff)
}
func (c *Chunk) Reader() (ChunkReader, error) {
if c.Value != nil {
log.Printf("Chunk %d: Reading from in-memory value\n", c.Id)
return bytes.NewReader(c.Value), nil
}
if c.Id != nil {
log.Printf("Chunk %d: Reading from file\n", c.Id)
return c.Id.Reader(c.Repo.path), nil
}
return nil, &ChunkError{"Uninitialized chunk"}
}
func (c *Chunk) isStored() bool {
return c.Id != nil
}
type ChunkError struct {
err string
}
func (e *ChunkError) Error() string {
return fmt.Sprintf("Chunk error: %s", e.err)
}
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