storage.gno

 1package simple
 2
 3import (
 4	"time"
 5
 6	"gno.land/p/demo/gnorkle/feed"
 7	"gno.land/p/demo/gnorkle/storage"
 8)
 9
10// Storage is simple, bounded storage for published feed values.
11type Storage struct {
12	values    []feed.Value
13	maxValues uint
14}
15
16// NewStorage creates a new Storage with the given maximum number of values.
17// If maxValues is 0, the storage is bounded to a size of one. If this is not desirable,
18// then don't provide a value of 0.
19func NewStorage(maxValues uint) *Storage {
20	if maxValues == 0 {
21		maxValues = 1
22	}
23
24	return &Storage{
25		maxValues: maxValues,
26	}
27}
28
29// Put adds a new value to the storage. If the storage is full, the oldest value
30// is removed. If maxValues is 0, the storage is bounded to a size of one.
31func (s *Storage) Put(value string) error {
32	if s == nil {
33		return storage.ErrUndefined
34	}
35
36	s.values = append(s.values, feed.Value{String: value, Time: time.Now()})
37	if uint(len(s.values)) > s.maxValues {
38		s.values = s.values[1:]
39	}
40
41	return nil
42}
43
44// GetLatest returns the most recently added value, or an empty value if none exist.
45func (s Storage) GetLatest() feed.Value {
46	if len(s.values) == 0 {
47		return feed.Value{}
48	}
49
50	return s.values[len(s.values)-1]
51}
52
53// GetHistory returns all values in the storage, from oldest to newest.
54func (s Storage) GetHistory() []feed.Value {
55	return s.values
56}