Bug 73472 – [MutationObservers] Make WebKitMutationObserver::deliverAllMutations() tolerant of re-entrant calls

• Status: RESOLVED
• Resolution: FIXED
• Component: DOM

[Rafael Weinstein]

In effect, deliverAllMutations() needs to prevent each delivery from, itself, causing deliverAllMutations().

The code happens to be structured right now in such a way that it's behavior is still semantically correct, but we should avoid having multiple calls on this static on the stack.

[Rafael Weinstein]

Created attachment 117228 [details]
Patch

[Ojan Vafai]

Comment on attachment 117228 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=117228&action=review

> Source/WebCore/dom/WebKitMutationObserver.cpp:139
> +        return;

Should we have an ASSERT_NOT_REACHED() before the return here? It's a bug in the C++ code if we ever hit this, right?

[Rafael Weinstein]

No. We probably will reach it. deliveryAllMutations is likely going to invoke script for each observer. The easiest thing is for each embedder to simply hook ALL outer-most script invocations. This guard just means that for each delivery, the embedder will *try* and quietly fail to re-start delivery (which is already underway).

[WebKit Review Bot]

Comment on attachment 117228 [details]
Patch

Clearing flags on attachment: 117228

Committed r101597: <http://trac.webkit.org/changeset/101597>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.