1886371 - [UIA] Implement foundations of native UIA implementation

Status: RESOLVED FIXED

(Core :: Disability Access APIs, task)

Description

[James Teh [:Jamie]]

Our current UIA implementation is based on IAccessibleEx. We want to do a proper native implementation because the IA2 -> UIA proxy is very slow (see bug 762769 comment 4) and has other bugs/quirks beyond our control.

In this bug, we will respond to WM_GETOBJECT as native UIA expects, implement tree traversal, and get our existing (small) UIA test suite passing.

Comment 1

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 1: Hook up our native UIA tree.

1. Respond to WM_GETOBJECT with our IRawElementProviderSimple implementation for the root Accessible of the HWND.
2. Don't allow QueryInterface to UIA interfaces if the UIA pref is disabled. This stops WM_GETOBJECT from returning our UIA implementation in this case.
3. Specify the appropriate provider options.

Comment 2

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 2: Refactor uiaRawElmProvider::QueryInterface.

Our IUnknownImpl macros avoid boilerplate, but they weren't designed to handle the quirky inheritance of our MSAA/UIA implementation.
Among other things, using these macros required us to override AddRef and Release in uiaRawElmProvider, which was a bit confusing.
Rather than perpetuating this weirdness as things get more complex, just implement what we need by hand.

Comment 3

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 3: Implement IRawElementProviderFragment.

This is how UIA traverses the tree.

Comment 4

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 4: Implement IRawElementProviderFragmentRoot.

This identifies the root of our implementation and allows for focus querying and hit testing.
We also implement IRawElementProviderSimple::get_HostRawElementProvider to connect to UIA's HWND provider.

Comment 5

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 5: Implement the UIA AutomationId property.

We need this for our tests so they can find elements they're testing.

Comment 6

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 6: Add UIA control types to RoleMap.

The actual ControlType property implementation is the subject of a subsequent patch.

Comment 7

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 7: Implement UIA ControlType property.

Aside from being a fundamental part of semantics, this is needed for our tests.
These mappings are based on the Core AAM and HTML AAM specs, plus some personal judgement where Gecko roles weren't covered by these specs.
UIA control types are rather limited and they apparently expect us to expose a lot of things using LocalizedControlType, but that isn't implemented for now.
I expect these will need to be revised in future, but this is a starting point.

Comment 8

[James Teh [:Jamie]]

Attachment: Bug 1886371 part 8: Tweak the test harness so that it uses native UIA when it is enabled.

See the code comments for explanation.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7a390b42c154
part 1: Hook up our native UIA tree. r=nlapre,win-reviewers,rkraesig
https://hg.mozilla.org/integration/autoland/rev/99e2e8077f6c
part 2: Refactor uiaRawElmProvider::QueryInterface. r=nlapre
https://hg.mozilla.org/integration/autoland/rev/106d9f34baf0
part 3: Implement IRawElementProviderFragment. r=nlapre
https://hg.mozilla.org/integration/autoland/rev/0535814eafd8
part 4: Implement IRawElementProviderFragmentRoot. r=nlapre
https://hg.mozilla.org/integration/autoland/rev/99f3316bea22
part 5: Implement the UIA AutomationId property. r=nlapre
https://hg.mozilla.org/integration/autoland/rev/6a0c55ad599b
part 6: Add UIA control types to RoleMap. r=nlapre
https://hg.mozilla.org/integration/autoland/rev/46bbfc5941c2
part 7: Implement UIA ControlType property. r=nlapre
https://hg.mozilla.org/integration/autoland/rev/19d905446a32
part 8: Tweak the test harness so that it uses native UIA when it is enabled. r=nlapre

Comment 10

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/7a390b42c154
https://hg.mozilla.org/mozilla-central/rev/99e2e8077f6c
https://hg.mozilla.org/mozilla-central/rev/106d9f34baf0
https://hg.mozilla.org/mozilla-central/rev/0535814eafd8
https://hg.mozilla.org/mozilla-central/rev/99f3316bea22
https://hg.mozilla.org/mozilla-central/rev/6a0c55ad599b
https://hg.mozilla.org/mozilla-central/rev/46bbfc5941c2
https://hg.mozilla.org/mozilla-central/rev/19d905446a32