diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/library/scala/collection/Iterator.scala | 29 |
1 files changed, 12 insertions, 17 deletions
diff --git a/src/library/scala/collection/Iterator.scala b/src/library/scala/collection/Iterator.scala index 0783beac0f..0f6ae47e89 100644 --- a/src/library/scala/collection/Iterator.scala +++ b/src/library/scala/collection/Iterator.scala @@ -10,7 +10,7 @@ package scala package collection import mutable.ArrayBuffer -import scala.annotation.migration +import scala.annotation.{ migration, tailrec } import immutable.Stream import scala.collection.generic.CanBuildFrom import scala.annotation.unchecked.{ uncheckedVariance => uV } @@ -580,29 +580,24 @@ trait Iterator[+A] extends TraversableOnce[A] { def span(p: A => Boolean): (Iterator[A], Iterator[A]) = { val self = buffered - /* - * Giving a name to following iterator (as opposed to trailing) because - * anonymous class is represented as a structural type that trailing - * iterator is referring (the finish() method) and thus triggering - * handling of structural calls. It's not what's intended here. - */ + // Must be a named class to avoid structural call to finish from trailing iterator class Leading extends AbstractIterator[A] { - val lookahead = new mutable.Queue[A] - def advance() = { - self.hasNext && p(self.head) && { + private val lookahead = new mutable.Queue[A] + private var finished = false + private def advance() = !finished && { + if (self.hasNext && p(self.head)) { lookahead += self.next true + } else { + finished = true + false } } - def finish() = { - while (advance()) () - } + @tailrec final def finish(): Unit = if (advance()) finish() def hasNext = lookahead.nonEmpty || advance() def next() = { - if (lookahead.isEmpty) - advance() - - lookahead.dequeue() + if (!hasNext) empty.next() + else lookahead.dequeue() } } val leading = new Leading |