indexes

type ByField interface {
	Add(index Index)
	Insert(item record.Record)
	Delete(item record.Record)
	Update(oldItem, item record.Record)
	SelectForCondition(condition where.Condition) (
		indexExists bool,
		count int,
		ids []storage.IDIterator,
		idsUnique bool,
		err error,
	)
}

type ConcurrentStorage interface {
	RLock()
	RUnlock()
	Unwrap() Storage
	Get(key Key) storage.IDStorage
	GetOrCreate(key Key) storage.IDStorage
}

type Index interface {
	Field() record.Field
	Unique() bool
	Compute() IndexComputer
	Weight(condition where.Condition) (canApplyIndex bool, weight IndexWeight)
	Select(condition where.Condition) (count int, ids []storage.IDIterator, err error)
	ConcurrentStorage() ConcurrentStorage
}

type IndexComputer interface {
	ForRecord(item record.Record) Key
	ForValue(value interface{}) Key
	Check(indexKey Key, comparator where.FieldComparator) (bool, error)
}

type IndexWeight uint8

type Key interface {
	Less(than Key) bool
}

type Storage interface {
	Get(key Key) storage.IDStorage
	Set(key Key, records storage.IDStorage)
}