// PrefixTransform constructs a KeyTransform with a pair of functions that
// add or remove the given prefix key.
//
// Warning: will panic if prefix not found when it should be there. This is
// to avoid insidious data inconsistency errors.
func PrefixTransform(prefix ds.Key) ktds.KeyTransform {
return &ktds.Pair{
// Convert adds the prefix
Convert: func(k ds.Key) ds.Key {
return prefix.Child(k)
},
// Invert removes the prefix. panics if prefix not found.
Invert: func(k ds.Key) ds.Key {
if !prefix.IsAncestorOf(k) {
fmt.Errorf("Expected prefix (%s) in key (%s)", prefix, k)
panic("expected prefix not found")
}
s := strings.TrimPrefix(k.String(), prefix.String())
return ds.NewKey(s)
},
}
}
func (ds *Datastore) Put(key datastore.Key, value interface{}) error {
ds.mu.Lock()
defer ds.mu.Unlock()
data, ok := value.([]byte)
if !ok {
return ErrInvalidType
}
ds.client.Append("SET", key.String(), data)
if ds.ttl != 0 {
ds.client.Append("EXPIRE", key.String(), ds.ttl.Seconds())
}
if err := ds.client.GetReply().Err; err != nil {
return fmt.Errorf("failed to put value: %s", err)
}
if ds.ttl != 0 {
if err := ds.client.GetReply().Err; err != nil {
return fmt.Errorf("failed to set expiration: %s", err)
}
}
return nil
}
func (ds *Datastore) Delete(key datastore.Key) (err error) {
ds.mu.Lock()
defer ds.mu.Unlock()
return ds.client.Cmd("DEL", key.String()).Err
}
func (ds *Datastore) Has(key datastore.Key) (exists bool, err error) {
ds.mu.Lock()
defer ds.mu.Unlock()
return ds.client.Cmd("EXISTS", key.String()).Bool()
}
func (ds *Datastore) Get(key datastore.Key) (value interface{}, err error) {
ds.mu.Lock()
defer ds.mu.Unlock()
return ds.client.Cmd("GET", key.String()).Bytes()
}
// KeyFilename returns the filename associated with `key`
func (d *Datastore) KeyFilename(key ds.Key) string {
return filepath.Join(d.path, key.String(), ObjectKeySuffix)
}