Bug 185239 – Widgets should hold a WeakPtr to their parents

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Brent Fulgham]

We don't have a parent/child destruction notification mechanism for Widgets and their enclosing ScrollViews. We should allow the Widget to hold a WeakPtr to the parent ScrollView so we can gracefully handle cases where the ScrollView has been removed from the current document by the Widget is still pending a final move operation.

[Brent Fulgham]

<rdar://problem/39741250>

[Brent Fulgham]

Created attachment 339390 [details]
Patch

[alan]

Comment on attachment 339390 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=339390&action=review

> Source/WebCore/platform/Widget.cpp:37
> +    m_parent = nullptr;

No need to null the weak ptr; unless we call init() outside of the object construction.

> Source/WebCore/platform/Widget.cpp:50
> +    m_parent = view ? view->createWeakPtr() : nullptr;

I'd rather use makeWeakPtr() helper here (with auto& weakPtrFactory() const { return m_weakFactory; } on the ScrollView.)

[Brent Fulgham]

Committed r231335: <https://trac.webkit.org/changeset/231335>

[alan]

>m_parent = view ? makeWeakPtr(*view) : nullptr;
You could just do 
m_parent = makeWeakPtr(view);
instead. makeWeakPtr handles nullptr.