Method BlockSoonWaiter

protocol/protocol.go:186–205

BlockSoonWaiter returns a channel that waits for the block at the given height, but it is an error to wait for a block far in the future. WaitForBlockSoon will timeout if the context times out. To wait unconditionally, the caller should use WaitForBlock.

(ctx context.Context, height uint64)

// WaitForBlockSoon will timeout if the context times out.
// To wait unconditionally, the caller should use WaitForBlock.
func (c *Chain) BlockSoonWaiter(ctx context.Context, height uint64) <-chan error {
	ch := make(chan error, 1)

	go func() {
		const slop = 3
		if height > c.Height()+slop {
			ch <- ErrTheDistantFuture
			return
		}

		select {
		case <-c.BlockWaiter(height):
			ch <- nil
		case <-ctx.Done():
			ch <- ctx.Err()
		}
	}()

	return ch
}

// BlockWaiter returns a channel that
// waits for the block at the given height.