seaweedfs/weed-fs/src/pkg/storage/needle.go
2012-07-16 17:15:16 +00:00

118 lines
2.9 KiB
Go

package storage
import (
"encoding/hex"
"io"
"io/ioutil"
"log"
"net/http"
"os"
"pkg/util"
"strconv"
"strings"
)
type Needle struct {
Cookie uint32 "random number to mitigate brute force lookups"
Key uint64 "file id"
Size uint32 "Data size"
Data []byte "The actual file data"
Checksum int32 "CRC32 to check integrity"
Padding []byte "Aligned to 8 bytes"
}
func NewNeedle(r *http.Request) (n *Needle, e error) {
n = new(Needle)
form, fe := r.MultipartReader()
if fe != nil {
log.Printf("MultipartReader [ERROR] %s\n", fe)
e = fe
return
}
part, _ := form.NextPart()
log.Println("uploading file " + part.FileName())
data, _ := ioutil.ReadAll(part)
n.Data = data
commaSep := strings.LastIndex(r.URL.Path, ",")
dotSep := strings.LastIndex(r.URL.Path, ".")
fid := r.URL.Path[commaSep+1:]
if dotSep > 0 {
fid = r.URL.Path[commaSep+1 : dotSep]
}
n.ParsePath(fid)
return
}
func (n *Needle) ParsePath(fid string) {
length := len(fid)
if length <= 8 {
if length > 0 {
log.Println("Invalid fid", fid, "length", length)
}
return
}
delta := ""
deltaIndex := strings.LastIndex(fid, "_")
if deltaIndex > 0 {
fid, delta = fid[0:deltaIndex], fid[deltaIndex+1:]
}
n.Key, n.Cookie = ParseKeyHash(fid)
if delta != "" {
d, e := strconv.ParseUint(delta, 10, 64)
if e == nil {
n.Key += d
}
}
}
func (n *Needle) Append(w io.Writer) uint32 {
header := make([]byte, 16)
util.Uint32toBytes(header[0:4], n.Cookie)
util.Uint64toBytes(header[4:12], n.Key)
n.Size = uint32(len(n.Data))
util.Uint32toBytes(header[12:16], n.Size)
w.Write(header)
w.Write(n.Data)
rest := 8 - ((n.Size + 16 + 4) % 8)
util.Uint32toBytes(header[0:4], uint32(n.Checksum))
w.Write(header[0 : rest+4])
return n.Size
}
func (n *Needle) Read(r io.Reader, size uint32) (int, error) {
bytes := make([]byte, size+16+4)
ret, e := r.Read(bytes)
n.Cookie = util.BytesToUint32(bytes[0:4])
n.Key = util.BytesToUint64(bytes[4:12])
n.Size = util.BytesToUint32(bytes[12:16])
n.Data = bytes[16 : 16+size]
n.Checksum = int32(util.BytesToUint32(bytes[16+size : 16+size+4]))
return ret, e
}
func ReadNeedle(r *os.File) (*Needle, uint32) {
n := new(Needle)
bytes := make([]byte, 16)
count, e := r.Read(bytes)
if count <= 0 || e != nil {
return nil, 0
}
n.Cookie = util.BytesToUint32(bytes[0:4])
n.Key = util.BytesToUint64(bytes[4:12])
n.Size = util.BytesToUint32(bytes[12:16])
rest := 8 - ((n.Size + 16 + 4) % 8)
r.Seek(int64(n.Size+4+rest), 1)
return n, 16 + n.Size + 4 + rest
}
func ParseKeyHash(key_hash_string string) (uint64, uint32) {
key_hash_bytes, khe := hex.DecodeString(key_hash_string)
key_hash_len := len(key_hash_bytes)
if khe != nil || key_hash_len <= 4 {
log.Println("Invalid key_hash", key_hash_string, "length:", key_hash_len, "error", khe)
return 0, 0
}
key := util.BytesToUint64(key_hash_bytes[0 : key_hash_len-4])
hash := util.BytesToUint32(key_hash_bytes[key_hash_len-4 : key_hash_len])
return key, hash
}