395081 - AccessibleObjectFromPoint returns errors

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect)

Description

[Aaron Leventhal]

1. Open MSAA Inspect and Mozilla
2. Hover of any object in a web page or the user interface

Inspect reports:
Cannot get object from point:
[Error AccessibleObjectFromPoint: hr=0x80004005 - Unspecified error]

Comment 1

[Aaron Leventhal]

Actually most of the UI elements are working. The menu bar is broken, though.

And nothing in content is working.

Comment 2

[Aaron Leventhal]

I think it cannot walk inside an outerdoc accessible into the inner doc accessible.

Comment 3

[Aaron Leventhal]

Attachment: WIP -- still won't walk into inner iframes or image maps

Comment 4

[Aaron Leventhal]

Attachment: 1) Fall back on walking through accessible children is still necessary, 2) Special case outer doc accessible and HTML area accessibles

Comment 5

[Aaron Leventhal]

It was a regression from bug 388927.

Comment 6

[Aaron Leventhal]

Unfortunately we're also broken in XUL trees/treeitems now, and this patch doesn't fix that.

Comment 7

[Aaron Leventhal]

Attachment: 1) Also clarify GetChildAtPoint() can return either null or |this| when no child has the point, 2) return correct answer in those cases, 3) fix XUL tree items

Comment 8

[Aaron Leventhal]

Attachment: Remove nsHyperTextAccesssible chunk (was for a different bug)

Comment 9

[alexander :surkov (:asurkov)]

Comment on attachment 279860 [details] [diff] [review]
Remove nsHyperTextAccesssible chunk (was for a different bug)


>+  if (MustPrune(this)) {  // Do not dig any further
>+    NS_IF_ADDREF(*aAccessible = fallbackAnswer);
>+    return NS_OK;
>+  }

Does MustPrune() not work here for nsLeafAccessible and nsHTMLAreaAccessible?

>+  if (accessible == this) {
>+    // Manually walk through accessible children and see if
>+    // the are within this point.
>+    // This takes care of cases where layout won't walk into
>+    // things for us, such as image map areas and sub documents

Do you mean GetFrameForPoint() doesn't look inside sub documents?

>+  NS_IMETHOD GetChildAtPoint(PRInt32 aX, PRInt32 aY, nsIAccessible **aAccessible)
>+    { *aAccessible = this; return NS_OK; } // Don't walk into these
> };

I would prefer to keep implementation inside cpp file.

>+NS_IMETHODIMP
>+nsOuterDocAccessible::GetChildAtPoint(PRInt32 aX, PRInt32 aY,
>+                                      nsIAccessible **aAccessible)
>+{
>+  NS_ENSURE_ARG_POINTER(aAccessible);
>+  *aAccessible = nsnull;
>+  if (!mDOMNode) {
>+    return NS_ERROR_FAILURE;
>+  }
>+  PRInt32 docX, docY, docWidth, docHeight;
>+  GetBounds(&docX, &docY, &docWidth, &docHeight);
>+  if (aX < docX || aX >= docX + docWidth || aY < docY || aY >= docY + docHeight) {
>+    return NS_ERROR_FAILURE;
>+  }
>+
>+  return GetFirstChild(aAccessible);  // Always return the inner doc unless bounds outside of it

sorry can you give me an example of accessible tree for this?

Comment 10

[Aaron Leventhal]

> Does MustPrune() not work here for nsLeafAccessible and nsHTMLAreaAccessible?
It doesn't currently work for those because it is a static method that is role based. I don't think it's worth making it virtual.

> Do you mean GetFrameForPoint() doesn't look inside sub documents?
Apparently not, from my tests.

> sorry can you give me an example of accessible tree for this?
Any XUL with an HTML document, created by for example <browser>

> I would prefer to keep implementation inside cpp file.
Mozilla uses inline methods all the time for small things. It's a standard C++ optimization.

Comment 11

[alexander :surkov (:asurkov)]

Comment on attachment 279860 [details] [diff] [review]
Remove nsHyperTextAccesssible chunk (was for a different bug)

r=me

Comment 12

[alexander :surkov (:asurkov)]

btw, please remove MustPrune check from platfom analogue methods like accHitTest()

Comment 13

[Aaron Leventhal]

Surkov, I filed follow-up bug 396603 for comment 12.

Comment 14

[Firefox Bug Husbandry Bot]

https://bugzilla.mozilla.org/show_bug.cgi?id=1527381