gno.land/p/gnoland/boards/v0⧉

1package boards23import (4	"errors"56	"gno.land/p/nt/bptree/v0"7	"gno.land/p/nt/seqid/v0"8)910type (11	// RepostIterFn defines a function type to iterate reposts.12	RepostIterFn func(board, repost ID) bool1314	// RepostStorage defines an interface for storing reposts.15	RepostStorage interface {16		// Get returns the repost ID for a board.17		Get(board ID) (repost ID, found bool)1819		// Add adds a new repost to the storage.20		Add(repost *Post) error2122		// Remove removes repost for a board.23		Remove(board ID) (removed bool)2425		// Size returns the number of reposts in the storage.26		Size() int2728		// Iterate iterates reposts.29		// To reverse iterate reposts use a negative count.30		// If the callback returns true, the iteration is stopped.31		Iterate(start, count int, fn RepostIterFn) bool32	}33)3435// NewRepostStorage creates a new storage for reposts.36// The new storage uses an AVL tree to store reposts.37func NewRepostStorage() RepostStorage {38	return &repostStorage{bptree.NewBPTree32()}39}4041type repostStorage struct {42	reposts *bptree.BPTree // string(Board.ID) -> Post.ID43}4445// Get returns the repost ID for a board.46func (s repostStorage) Get(boardID ID) (ID, bool) {47	v := s.reposts.Get(boardID.Key())48	if v == nil {49		return 0, false50	}51	return v.(ID), true52}5354// Add adds a new repost to the storage.55func (s *repostStorage) Add(repost *Post) error {56	if repost == nil {57		return errors.New("saving nil reposts is not allowed")58	}5960	s.reposts.Set(repost.Board.ID.Key(), repost.ID)61	return nil62}6364// Remove removes repost for a board.65func (s *repostStorage) Remove(boardID ID) bool {66	_, removed := s.reposts.Remove(boardID.Key())67	return removed68}6970// Size returns the number of reposts in the storage.71func (s repostStorage) Size() int {72	return s.reposts.Size()73}7475// Iterate iterates reposts.76// To reverse iterate reposts use a negative count.77// If the callback returns true, the iteration is stopped.78func (s repostStorage) Iterate(start, count int, fn RepostIterFn) bool {79	if count < 0 {80		return s.reposts.ReverseIterateByOffset(start, -count, func(k string, v any) bool {81			id, err := seqid.FromString(k)82			if err != nil {83				panic(err)84			}8586			return fn(ID(id), v.(ID))87		})88	}8990	return s.reposts.IterateByOffset(start, count, func(k string, v any) bool {91		id, err := seqid.FromString(k)92		if err != nil {93			panic(err)94		}9596		return fn(ID(id), v.(ID))97	})98}99