208898 - In-process accessibility clients need XPCOM notification of newly initiialized doc views

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect)

Description

[Aaron Leventhal]

The closest way I can find to start the accessibility tree building process is
to use nsIWebProgressListner, and wait for a StateChange of STATE_TRANSFERRING.

However, 1) it's not a frozen interface and 2) it's a lot of code to listen for
just that.

Comment 1

[Aaron Leventhal]

Attachment: Uses nsIObserverService to fire notification that new viewable document is ready

Comment 2

[Johnny Stenback (:jst)]

Comment on attachment 125301 [details] [diff] [review]
Uses nsIObserverService to fire notification that new viewable document is ready

I don't see a lot of users being interested in this notification, and assuming
using nsIWebProgress works, I'd suggest going with that, even if it's not just
a few lines of code to do that (assuming it's not pages and pages worth of
code, which I doubt).

r- for now, let me know if you strongly disagree.

Comment 3

[Aaron Leventhal]

Johnny, the problem is that nsIWebProgress* are "under review". I doubt if
they'll be frozen for 1.4. 

Comment 4

[Aaron Leventhal]

Jst, bug 99639 is the bug to freeze the nsIWebProg* interfaces, but it's minused.

Comment 5

[Darin Fisher]

no, nsIWebProgress* won't be frozen for 1.4 ... maybe sometime in the future ;)

Comment 6

[Aaron Leventhal]

Attachment: nsAccessibilityservice uses doc loader service to learn about new docs, and then generates accessibles and accessible events for them

Comment 7

[Kyle Yuan]

Comment on attachment 126378 [details] [diff] [review]
nsAccessibilityservice uses doc loader service to learn about new docs, and then generates accessibles and accessible events for them

>+  const kRequiredFlags = STATE_IS_DOCUMENT|STATE_TRANSFERRING;
iirc, STATE_IS_DOCUMENT|STATE_STOP would be the right event you want to check.
Please double check with the guys who is familiar with this.

Comment 8

[Aaron Leventhal]

Kyle, I want STATE_TRANSFERRING, otherwise it won't create the accesible until
the doc is fully finished loading. I want an event at the start of the load, and
one at the end.

Comment 9

[Aaron Leventhal]

Kyle, STATE_TRANSFERRING is definitely what I want. It's always fired at the
start of the load. However, STATE_START is too early because there is no
document node yet.

It is important to create the accessible early because the user can interact
with the document before it finishes loading. The user can tab/scroll around and
edit forms. All of these things can happen before the doc finishes loading and
it is important to get the accessibility events for those things too.

Comment 10

[Kyle Yuan]

Comment on attachment 126378 [details] [diff] [review]
nsAccessibilityservice uses doc loader service to learn about new docs, and then generates accessibles and accessible events for them

sorry, I was unable to access bugzilla for a while. r=kyle.

Comment 11

[Aaron Leventhal]

Comment on attachment 126378 [details] [diff] [review]
nsAccessibilityservice uses doc loader service to learn about new docs, and then generates accessibles and accessible events for them

No problem. Thanks Kyle.

Seeking sr=jst

Comment 12

[Johnny Stenback (:jst)]

Comment on attachment 126378 [details] [diff] [review]
nsAccessibilityservice uses doc loader service to learn about new docs, and then generates accessibles and accessible events for them

- In nsAccessibilityService::OnStateChange():

+  const kRequiredFlags = STATE_IS_DOCUMENT|STATE_TRANSFERRING;
+  if ((aStateFlags & kRequiredFlags ) != kRequiredFlags) {

Be consistent with space-around-binary-operators, i.e. add spaces before and
after '|' (makes it more readable too).

sr=jst

Comment 13

[Aaron Leventhal]

checked in

Comment 14

[Kyle Yuan]

Comment on attachment 126378 [details] [diff] [review]
nsAccessibilityservice uses doc loader service to learn about new docs, and then generates accessibles and accessible events for them

For making the accessibility feature work better and more stable in 1.4.x, we
need to get this patch in. This fix has been in trunk for a long period. It
won't affect other modules.

Comment 15

[Asa Dotzler [:asa]]

Comment on attachment 126378 [details] [diff] [review]
nsAccessibilityservice uses doc loader service to learn about new docs, and then generates accessibles and accessible events for them

This is not going to make 1.4.1.  Please re-request aproval after 1.4.1 ships
if you'd like to get this in for 1.4.2. 
Kyle, can you all take this into your tree locally until after 1.4.1 ships
(real soon now) and then work with us to get it landed first thing for 1.4.2?