1365654 - Hash table Enum objects cannot be returned from a function

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement)

Description

[Jon Coppeard (:jonco)]

Hash table Enum objects have a deleted copy constructor and hence a deleted move constructor, so you can't do this:

using Map = js::HashMap<int, int, js::DefaultHasher<int>, js::SystemAllocPolicy>;

Map::Enum enumerateSuff()
{
    return Map::Enum(map);
}

We should give Enum a move constructor to allow this reasonable behaviour.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: bug1365654-enum-move

Add a move constructor to HashTable::Enum.

Comment 2

[Luke Wagner [:luke]]

Comment on attachment 8868998 [details] [diff] [review]
bug1365654-enum-move

Review of attachment 8868998 [details] [diff] [review]:
-----------------------------------------------------------------

Makes sense

::: js/src/jsapi-tests/testHashTable.cpp
@@ +388,5 @@
>  
>  END_TEST(testHashMapLookupWithDefaultOOM)
>  #endif // defined(DEBUG)
> +
> +BEGIN_TEST(testHashTableMovableEnum)

Could you add a test that creates an Enum e1, removes an element or two, move-constructs an Enum e2, and then removes a few more elements?

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/2996f5f166a2
Add a move constructor to HashTable::Enum r=luke

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/e6f10f6af43d
Fix style bustage r=me

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/2996f5f166a2
https://hg.mozilla.org/mozilla-central/rev/e6f10f6af43d