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package storage
import (
"bytes"
"code.laria.me/petrific/objects"
"errors"
"fmt"
"io"
)
var (
ObjectNotFound = errors.New("Object not found")
)
type Storage interface {
Get(id objects.ObjectId) ([]byte, error)
Has(id objects.ObjectId) (bool, error)
Set(id objects.ObjectId, typ objects.ObjectType, raw []byte) error
List(typ objects.ObjectType) ([]objects.ObjectId, error)
}
func SetObject(s Storage, o objects.RawObject) (id objects.ObjectId, err error) {
buf := new(bytes.Buffer)
id, err = o.SerializeAndId(buf, objects.OIdAlgoDefault)
if err != nil {
return
}
ok, err := s.Has(id)
if err != nil {
return
}
if !ok {
err = s.Set(id, o.Type, buf.Bytes())
}
return
}
type IdMismatchErr struct {
Want, Have objects.ObjectId
}
func (iderr IdMismatchErr) Error() string {
return fmt.Sprintf("ID verification failed: want %s, have %s", iderr.Want, iderr.Have)
}
// GetObjects gets an object from a Storage and parses and verifies it (check it's checksum/id)
func GetObject(s Storage, id objects.ObjectId) (objects.RawObject, error) {
raw, err := s.Get(id)
if err != nil {
return objects.RawObject{}, err
}
idgen := id.Algo.Generator()
r := io.TeeReader(bytes.NewReader(raw), idgen)
obj, err := objects.Unserialize(r)
if err != nil {
return objects.RawObject{}, err
}
if have_id := idgen.GetId(); !have_id.Equals(id) {
return objects.RawObject{}, IdMismatchErr{id, have_id}
}
return obj, nil
}
func GetObjectOfType(s Storage, id objects.ObjectId, t objects.ObjectType) (objects.Object, error) {
rawobj, err := GetObject(s, id)
if err != nil {
return nil, err
}
if rawobj.Type != t {
return nil, fmt.Errorf("GetObjectOfType: Wrong object type %s (want %s)", rawobj.Type, t)
}
return rawobj.Object()
}
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