restic/backend/generic.go
2014-10-03 21:44:55 +02:00

84 lines
1.3 KiB
Go

package backend
import (
"bytes"
"compress/zlib"
"crypto/sha256"
"io/ioutil"
)
// Each lists all entries of type t in the backend and calls function f() with
// the id and data.
func Each(be Server, t Type, f func(id ID, data []byte, err error)) error {
ids, err := be.List(t)
if err != nil {
return err
}
for _, id := range ids {
data, err := be.Get(t, id)
if err != nil {
f(id, nil, err)
continue
}
f(id, data, nil)
}
return nil
}
// Each lists all entries of type t in the backend and calls function f() with
// the id.
func EachID(be Server, t Type, f func(ID)) error {
ids, err := be.List(t)
if err != nil {
return err
}
for _, id := range ids {
f(id)
}
return nil
}
// Compress applies zlib compression to data.
func Compress(data []byte) []byte {
// apply zlib compression
var b bytes.Buffer
w := zlib.NewWriter(&b)
_, err := w.Write(data)
if err != nil {
panic(err)
}
w.Close()
return b.Bytes()
}
// Uncompress reverses zlib compression on data.
func Uncompress(data []byte) []byte {
b := bytes.NewBuffer(data)
r, err := zlib.NewReader(b)
if err != nil {
panic(err)
}
buf, err := ioutil.ReadAll(r)
if err != nil {
panic(err)
}
r.Close()
return buf
}
// Hash returns the ID for data.
func Hash(data []byte) ID {
h := sha256.Sum256(data)
id := make(ID, 32)
copy(id, h[:])
return id
}