AX: Add the ability to dump the accessibility tree via notifyutil

[twilco]

3bcec6c

AX: Add the ability to dump the accessibility tree via notifyutil
https://bugs.webkit.org/show_bug.cgi?id=295101
rdar://154490712

Reviewed by Joshua Hoffman.

After this commit, with a build of WebKit that has ENABLE(TREE_DEBUGGING), one can run:

notifyutil -p com.apple.WebKit.showAccessibilityTree

To dump the accessibility tree on-demand.

Also, when ENABLE(INCLUDE_IGNORED_IN_CORE_AX_TREE), this commit changes streamAXCoreObject to print the parent object
(including ignored), and streamSubtree to print ignored children.

* Source/WebCore/accessibility/AXCoreObject.h:
(WebCore::AXCoreObject::parentInCoreTree const):
* Source/WebCore/accessibility/AXLogger.cpp:
(WebCore::streamSubtree):
* Source/WebCore/accessibility/AXObjectCache.cpp:
(WebCore::showAccessibilityTree):
* Source/WebCore/accessibility/AXObjectCache.h:
* Source/WebCore/accessibility/AccessibilityObject.h:
(WebCore::AccessibilityObject::parentInCoreTree const): Deleted.
* Source/WebCore/accessibility/isolatedtree/AXIsolatedTree.cpp:
(WebCore::AXIsolatedTree::updateNode):
* Source/WebCore/page/cocoa/PageCocoa.mm:
(WebCore::Page::platformInitialize):
* Source/WebCore/rendering/RenderObject.cpp:
(WebCore::printAccessibilityTreeForLiveDocuments):
* Source/WebCore/rendering/RenderObject.h:
* Source/WebKit/Resources/cocoa/NotificationAllowList/ForwardedNotifications.def:

Canonical link: https://commits.webkit.org/296746@main

dca0422

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
❌ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	⏳ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 19c7c72)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
❌ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	⏳ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	⏳ 🧪 wpe-wk2	⏳ 🧪 win-tests
✅ 🧪 webkitperl	🧪 ios-wk2	✅ 🧪 api-mac	🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[minorninth]

Love it!

[minorninth]

How about dumpAccessibilityTreeToStderr or something more specific? Show makes it sound like it will be visual

[twilco]

Yeah agreed. The reason I chose this name is to follow the pattern of the other notifyutil tree dump functions, e.g.:

showLayerTree

showRenderTree

showPaintOrderTree

But I don't think we really need to follow the pattern in this case, so I'll change it.

[minorninth]

Does WTFLogAlways do the same as fprintf to stderr, with the same buffering and everything? I think it'd be best if all of the code that logs uses the same mechanism

[twilco]

WTFLogAlways is a thin-wrapper over this:

// Assertions.cpp
void WTFLogAlwaysV(const char* format, va_list args)
{
    vprintf_stderr_with_trailing_newline(nullptr, format, args);
}

So seems like it's always stderr?

I mostly chose WTFLogAlways to follow the pattern of the several other similar "dump tree" methods, e.g.:

printLayerTreeForLiveDocuments

printRenderTreeForLiveDocuments

printPaintOrderTreeForLiveDocuments

...and a few others

Would you prefer we explicitly fprintf(stderr, ""); here?

[minorninth]

If they're both directly printing to stderr then it's fine. I've just been bitten by, e.g. mixing cerr and stderr because they have separate buffering.

[webkit-early-warning-system]

EWS run on current version of this PR (hash dca0422)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows
❌ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	⏳ 🧪 win-tests
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	🧪 api-gtk
✅ 🛠 🧪 merge	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 296746@main (3bcec6c): https://commits.webkit.org/296746@main

Reviewed commits have been landed. Closing PR #47299 and removing active labels.