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|
package main
import (
"bufio"
"bytes"
"fmt"
"io"
"log"
"os"
"path"
)
type ChunkReader interface {
io.Reader
io.ByteReader
}
type Chunk interface {
Reader() ChunkReader
Len() int
}
type IdentifiedChunk interface {
Chunk
Id() *ChunkId
}
type BufferedChunk interface {
Chunk
Bytes() []byte
}
type ChunkId struct {
Ver int
Idx uint64
}
func (i *ChunkId) Path(repo string) string {
return path.Join(repo, fmt.Sprintf(versionFmt, i.Ver), chunksName, fmt.Sprintf(chunkIdFmt, i.Idx))
}
func (i *ChunkId) Reader(repo *Repo) ChunkReader {
path := i.Path(repo.path)
f, err := os.Open(path)
if err != nil {
log.Println("Cannot open chunk: ", path)
}
return bufio.NewReaderSize(f, repo.chunkSize)
}
func NewLoadedChunk(id *ChunkId, value []byte) *LoadedChunk {
return &LoadedChunk{id: id, value: value}
}
type LoadedChunk struct {
id *ChunkId
value []byte
}
func (c *LoadedChunk) Id() *ChunkId {
return c.id
}
func (c *LoadedChunk) Reader() ChunkReader {
// log.Printf("Chunk %d: Reading from in-memory value\n", c.id)
return bytes.NewReader(c.value)
}
func (c *LoadedChunk) Len() int {
return len(c.value)
}
func (c *LoadedChunk) Bytes() []byte {
return c.value
}
func NewStoredFile(repo *Repo, id *ChunkId) *StoredChunk {
return &StoredChunk{repo: repo, id: id}
}
type StoredChunk struct {
repo *Repo
id *ChunkId
}
func (c *StoredChunk) Id() *ChunkId {
return c.id
}
func (c *StoredChunk) Reader() ChunkReader {
// log.Printf("Chunk %d: Reading from file\n", c.id)
return c.id.Reader(c.repo)
}
func (c *StoredChunk) Len() int {
path := c.id.Path(c.repo.path)
info, err := os.Stat(path)
if err != nil {
log.Println("Chunk: could not stat file:", path)
}
return int(info.Size())
}
func NewTempChunk(value []byte) *TempChunk {
return &TempChunk{value: value}
}
type TempChunk struct {
value []byte
}
func (c *TempChunk) Reader() ChunkReader {
return bytes.NewReader(c.value)
}
func (c *TempChunk) Len() int {
return len(c.value)
}
func (c *TempChunk) Bytes() []byte {
return c.value
}
func (c *TempChunk) AppendFrom(r io.Reader) {
buff, err := io.ReadAll(r)
if err != nil {
println("Chunk: error appending to temp chunk:", err)
}
c.value = append(c.value, buff...)
}
type DeltaChunk struct {
repo *Repo
source *ChunkId
patch []byte
size int
}
func (c *DeltaChunk) Reader() ChunkReader {
var buff bytes.Buffer
c.repo.Patcher().Patch(c.source.Reader(c.repo), &buff, bytes.NewReader(c.patch))
return &buff
}
// TODO: Maybe return the size of the patch instead ?
func (c *DeltaChunk) Len() int {
return c.size
}
|
