diff options
| -rw-r--r-- | src/library/scala/collection/mutable/HashTable.scala | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/src/library/scala/collection/mutable/HashTable.scala b/src/library/scala/collection/mutable/HashTable.scala index db4e100634..fa3865ada2 100644 --- a/src/library/scala/collection/mutable/HashTable.scala +++ b/src/library/scala/collection/mutable/HashTable.scala @@ -144,18 +144,20 @@ trait HashTable[A] { } } - protected final def foreachEntry[C](f: Entry => C) { - val t = table - var index = t.length - 1 - while (index >= 0) { - var entry = t(index) - while (entry ne null) { - f(entry.asInstanceOf[Entry]) - entry = entry.next - } - index -= 1 - } - } + /* + * We should implement this as a primitive operation over the underlying array, but it can + * cause a behaviour change in edge cases where: + * - Someone modifies a map during iteration + * - The insertion point is close to the iteration point. + * + * The reason this happens is that the iterator prefetches the following element before + * returning from next (to simplify the implementation of hasNext) while the natural + * implementation of foreach does not. + * + * It should be mentioned that modifying a map during iteration leads to unpredictable + * results with either implementation. + */ + protected final def foreachEntry[C](f: Entry => C) { entriesIterator.foreach(f) } /** An iterator returning all entries */ @deprecated("use entriesIterator instead") |