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|
package state
import (
"errors"
"maps"
)
var (
ErrDuplicate = errors.New("store contains duplicates")
)
/*
Joiner is the interface that wraps the Join method.
The Join function uses Joiner if available.
*/
type Joiner interface{ Join() (Entries, error) }
// Join returns joined state entries of all active aids.
func Join(s Store) (Entries, error) {
if j, ok := s.(Joiner); ok {
return j.Join()
}
var (
aids []int
entries = make(Entries)
el int
res Entries
loadErr error
)
if ln, err := s.List(); err != nil {
return nil, err
} else {
aids = ln
}
for _, aid := range aids {
if _, err := s.Do(aid, func(c Cursor) {
res, loadErr = c.Load()
}); err != nil {
return nil, err
}
if loadErr != nil {
return nil, loadErr
}
// save expected length
el = len(entries) + len(res)
maps.Copy(entries, res)
if len(entries) != el {
return nil, ErrDuplicate
}
}
return entries, nil
}
|
