func (qdi QuadDirectionIndex) Tree(d quad.Direction, id int64) *b.Tree {
if d < quad.Subject || d > quad.Label {
panic("illegal direction")
}
tree, ok := qdi.index[d-1][id]
if !ok {
tree = b.TreeNew(cmp)
qdi.index[d-1][id] = tree
}
return tree
}
func (qdi *QuadDirectionIndex) Tree(d quad.Direction, id int64) *Tree {
if d < quad.Subject || d > quad.Label {
panic("illegal direction")
}
qdi.mu.RLock()
tree, ok := qdi.index[d-1][id]
qdi.mu.RUnlock()
if !ok {
qdi.mu.Lock()
tree, ok = qdi.index[d-1][id]
if !ok {
tree = &Tree{tree: b.TreeNew(cmp)}
qdi.index[d-1][id] = tree
}
qdi.mu.Unlock()
}
return tree
}