advsql/query_many.go

package advsql

import "context"

func QueryMany[T any](db *Database, query string, decoder func(v *T, decode ScanFunc) error) QueryManyFunc[T] {
	ctxfunc := QueryManyContext(db, query, decoder)
	return func(args ...interface{}) <-chan *T {
		return ctxfunc(context.Background(), args...)
	}
}

func QueryManyContext[T any](db *Database, query string, decoder func(v *T, decode ScanFunc) error) QueryManyContextFunc[T] {
	s, err := db.db.Prepare(query)
	if err != nil {
		return nil
	}
	db.closefuncs = append(db.closefuncs, s.Close)

	return func(ctx context.Context, args ...interface{}) <-chan *T {
		out := make(chan *T, 10)

		rows, err := s.QueryContext(ctx, args...)
		if err != nil {
			panic(err)
		}

		go func() {
			defer rows.Close()
			defer close(out)
			for rows.Next() {
				v := new(T)
				if decoder(v, rows.Scan) == nil {
					out <- v
				}
			}
		}()

		return out
	}
}