wtf.go

func (cn *connection) iterUnbiasedPieceRequestOrder(f func(piece int) bool) bool {
	now, readahead := cn.t.readerPiecePriorities()
	var skip bitmap.Bitmap
	if !cn.peerSentHaveAll {
		// Pieces to skip include pieces the peer doesn't have.
		skip = bitmap.Flip(cn.peerPieces, 0, cn.t.numPieces())
	}
	// And pieces that we already have.
	skip.Union(cn.t.completedPieces)
	skip.Union(cn.t.piecesQueuedForHash)
	// Return an iterator over the different priority classes, minus the skip
	// pieces.
	return iter.All(
		func(_piece interface{}) bool {
			i := _piece.(pieceIndex)
			if cn.t.hashingPiece(i) {
				return true
			}
			return f(i)
		},
		iterBitmapsDistinct(&skip, now, readahead),
		func(cb iter.Callback) {
			cn.t.pendingPieces.IterTyped(func(piece int) bool {
				if skip.Contains(piece) {
					return true
				}
				more := cb(piece)
				skip.Add(piece)
				return more
			})
		},
	)
}