1010760 - Add nsINode::IsText, AsText like for Element

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, enhancement)

Description

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

It's better to call AsElement than cast to Element, because it asserts that it actually is an element.  Likewise it would be good to have for Text and nsIContent.  IsText() is a lot easier to type and read than IsNodeOfType(nsINode::eTEXT).

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

We have IsContent and AsContent

Comment 2

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

Attachment: Patch

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

Comment on attachment 8471546 [details] [diff] [review]
Patch

IsContent and IsElement are non-virtual and inlined.
It would be odd if IsText() behaved significantly slower.
We need a bool flag.

Comment 4

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

Do you actually want me to add a bool flag?  I don't imagine there would be enough callers to justify it.  If not, what would you prefer instead?  The code pattern we have right now is

  if (node->IsNodeOfType(nsINode::eTEXT)) {
    nsCOMPtr<Text> textNode = static_cast<Text>(node);
    // . . .

which is bad because a) it's long to type, and b) the static_cast has no safety check in debug builds.  If you would prefer, I could add just AsText() and not IsText(), which would solve (b), although the asymmetry in the API would be confusing.

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

I want IsFoo methods to have same performance characteristics, so bool flag would be needed.

Would GetAsText() work? That hints that it may return null, and implementation could be then
something like.
Text* GetAsText()
{
  return IsNodeOfType(nsINode::eTEXT) ? static_cast<Text*>(this) : nullptr;
}

Comment 6

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

Attachment: Patch v2

Comment 7

[Aryeh Gregor (:ayg) (no longer with Mozilla)]

Try: https://tbpl.mozilla.org/?tree=Try&rev=52ee018a8367

http://hg.mozilla.org/integration/mozilla-inbound/rev/1ebef29c93f6

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/1ebef29c93f6