/
state_indexer.go
56 lines (46 loc) · 1.15 KB
/
state_indexer.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
package state
import (
"fmt"
"github.com/alphabill-org/alphabill/types"
)
// stateIndexer traverses the state tree and constructs an index using the keyExtractor
type (
stateIndexer[T comparable] struct {
index Index[T]
err error
keyExtractor KeyExtractor[T]
}
Index[T comparable] map[T][]types.UnitID
KeyExtractor[T comparable] func(unit *Unit) (T, error)
)
func (s *stateIndexer[T]) Traverse(n *node) {
if n == nil || s.err != nil {
return
}
s.Traverse(n.Left())
s.Traverse(n.Right())
unit := n.Value()
key, err := s.keyExtractor(unit)
if err != nil {
s.err = fmt.Errorf("failed to extract index key: %w", err)
return
}
var zero T
if key != zero {
s.index[key] = append(s.index[key], n.Key())
}
}
func CreateIndex[T comparable](s *State, ke KeyExtractor[T]) (Index[T], error) {
indexer := &stateIndexer[T]{
index: Index[T]{},
keyExtractor: ke,
}
s.Traverse(indexer)
if indexer.err != nil {
return nil, fmt.Errorf("failed to traverse state tree: %w", indexer.err)
}
return indexer.index, nil
}
func (s *State) CreateIndex(ke KeyExtractor[string]) (Index[string], error) {
return CreateIndex(s, ke)
}