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package operation
import (
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"sort"
"github.com/chrislusf/seaweedfs/go/util"
)
var ErrOutOfRange = errors.New("Out of Range")
type ChunkInfo struct {
Fid string `json:"fid,omitempty"`
Offset int64 `json:"offset,omitempty"`
Size int64 `json:"size,omitempty"`
}
type ChunkList []*ChunkInfo
type ChunkedFile struct {
Name string `json:"name,omitempty"`
Mime string `json:"mime,omitempty"`
Size int64 `json:"size,omitempty"`
Chunks ChunkList `json:"chunks,omitempty"`
master string `json:"-"`
}
func (s ChunkList) Len() int { return len(s) }
func (s ChunkList) Less(i, j int) bool { return s[i].Offset < s[j].Offset }
func (s ChunkList) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func NewChunkedNeedle(buffer []byte, master string) (*ChunkedFile, error) {
c := ChunkedFile{}
if e := json.Unmarshal(buffer, c); e != nil {
return nil, e
}
sort.Sort(c.Chunks)
c.master = master
return &c, nil
}
func (c *ChunkedFile) Marshal() ([]byte, error) {
return json.Marshal(c)
}
func copyChunk(fileUrl string, w io.Writer, startOffset, size int64) (written int64, e error) {
req, err := http.NewRequest("GET", fileUrl, nil)
if err != nil {
return written, err
}
if startOffset > 0 {
req.Header.Set("Range", fmt.Sprintf("bytes=%d-", startOffset))
}
resp, err := util.Do(req)
if err != nil {
return written, err
}
defer resp.Body.Close()
if startOffset > 0 && resp.StatusCode != 206 {
return written, fmt.Errorf("Cannot Read Needle Position: %d [%s]", startOffset, fileUrl)
}
if size > 0 {
return io.CopyN(w, resp.Body, size)
} else {
return io.Copy(w, resp.Body)
}
}
func (c *ChunkedFile) WriteBuffer(w io.Writer, offset, size int64) (written int64, e error) {
if offset >= c.Size || offset+size > c.Size {
return written, ErrOutOfRange
}
chunkIndex := -1
chunkStartOffset := int64(0)
for i, ci := range c.Chunks {
if offset >= ci.Offset && offset < ci.Offset+ci.Size {
chunkIndex = i
chunkStartOffset = offset - ci.Offset
break
}
}
if chunkIndex < 0 {
return written, ErrOutOfRange
}
//preload next chunk?
for ; chunkIndex < c.Chunks.Len(); chunkIndex++ {
ci := c.Chunks[chunkIndex]
fileUrl, lookupError := LookupFileId(c.master, ci.Fid)
if lookupError != nil {
return written, lookupError
}
rsize := int64(0)
if size > 0 {
rsize = size - written
}
if n, e := copyChunk(fileUrl, w, chunkStartOffset, rsize); e != nil {
return written, e
} else {
written += n
}
if size > 0 && written >= size {
break
}
chunkStartOffset = 0
}
return written, nil
}
func (c *ChunkedFile) DeleteHelper() error {
//TODO Delete all chunks
return nil
}
func (c *ChunkedFile) StoredHelper() error {
//TODO
return nil
}
|
