Support screen reader focus and activate on message history rows

rezabakhshilaktasaraei · rezabakhshilaktasaraei · commit 846f2921b4e1 · 2026-07-09T15:46:00.000+03:30
diff --git a/Telegram/SourceFiles/history/history_inner_widget.cpp b/Telegram/SourceFiles/history/history_inner_widget.cpp
@@ -2408,6 +2408,10 @@ void HistoryInner::itemRemoved(not_null<const HistoryItem*> item) {
 	if (_dragStateItem == item) {
 		_dragStateItem = nullptr;
 	}
+	if (_accessibilityFocusedItem == item) {
+		_accessibilityFocusedItem = nullptr;
+	}
+	_accessibilityIdentities.remove(item);
 
 	if ((_dragSelFrom && _dragSelFrom->data() == item)
 		|| (_dragSelTo && _dragSelTo->data() == item)) {
@@ -6440,3 +6444,142 @@ void HistoryInner::focusInEvent(QFocusEvent *e) {
 		setAccessibilityFocusedItem(index, item);
 	});
 }
+
+bool HistoryInner::accessibilityChildSupportsActions(int index) const {
+	// Every message row can be focused and activated and has a stable
+	// identity below. Tying the opt-in to a valid identity keeps the
+	// action interface off invalid indices and off the unread bar row,
+	// which has no meaningful press action.
+	return accessibilityChildIdentity(index) != 0;
+}
+
+quintptr HistoryInner::accessibilityChildIdentity(int index) const {
+	// Child indices shift whenever messages are inserted or removed and
+	// the unread bar appears or goes away, so a queued action must not
+	// be dispatched by index. A raw HistoryItem pointer is not a safe
+	// token either: items are destroyed all the time and a new message
+	// can be allocated at the same address, silently rebinding a stale
+	// provider to an unrelated row (ABA). So the first request issues
+	// the item a token from a monotonic counter; itemRemoved() erases
+	// the pointer->token entry, and an item reusing the address gets a
+	// fresh token, so stale identities resolve to nothing. The unread
+	// bar row deliberately has no identity (and no action interface).
+	const auto barIndex = accessibilityUnreadBarIndex();
+	if (barIndex >= 0 && index == barIndex) {
+		return 0;
+	}
+	const auto elements = accessibleElements();
+	const auto elementIndex = (barIndex >= 0 && index > barIndex)
+		? (index - 1)
+		: index;
+	if (elementIndex < 0 || elementIndex >= int(elements.size())) {
+		return 0;
+	}
+	const auto item = elements[elementIndex]->data();
+	const auto i = _accessibilityIdentities.find(item);
+	if (i != _accessibilityIdentities.end()) {
+		return i->second;
+	}
+	const auto token = ++_accessibilityIdentityCounter;
+	_accessibilityIdentities.emplace(item, token);
+	return token;
+}
+
+int HistoryInner::accessibilityChildIndexByIdentity(
+		quintptr identity) const {
+	// One pass over the elements looking each item up in the issued
+	// tokens map: only an item that was already handed out a token can
+	// match, so rows never seen by the accessibility layer just do not
+	// compare equal.
+	if (!identity) {
+		return -1;
+	}
+	const auto elements = accessibleElements();
+	const auto barIndex = accessibilityUnreadBarIndex();
+	for (auto i = 0, n = int(elements.size()); i != n; ++i) {
+		const auto j = _accessibilityIdentities.find(
+			elements[i]->data());
+		if (j != _accessibilityIdentities.end()
+			&& j->second == identity) {
+			return (barIndex >= 0 && i >= barIndex) ? (i + 1) : i;
+		}
+	}
+	return -1;
+}
+
+void HistoryInner::applyAccessibilityFocus(
+		int index,
+		bool announceAlways) {
+	const auto elements = accessibleElements();
+	const auto barIndex = accessibilityUnreadBarIndex();
+	const auto elementIndex = (barIndex >= 0 && index > barIndex)
+		? (index - 1)
+		: index;
+	const auto item = (elementIndex >= 0
+		&& elementIndex < int(elements.size()))
+		? elements[elementIndex]->data().get()
+		: nullptr;
+	const auto changed = (_accessibilityFocusedIndex != index)
+		|| (_accessibilityFocusedItem != item);
+	_accessibilityFocusedIndex = index;
+	_accessibilityFocusedItem = item;
+	// Exactly one announcement: directly when the widget already has
+	// focus, via focusInEvent when keyboard focus is being taken.
+	if (hasFocus()) {
+		if (changed || announceAlways) {
+			announceAccessibilityFocus(index);
+		}
+	} else {
+		setFocus();
+	}
+	const auto rect = accessibilityChildRect(index);
+	if (!rect.isEmpty()) {
+		if (rect.top() < _visibleAreaTop) {
+			_scroll->scrollToY(rect.top());
+		} else if (rect.bottom() > _visibleAreaBottom) {
+			_scroll->scrollToY(rect.bottom()
+				- (_visibleAreaBottom - _visibleAreaTop));
+		}
+	}
+	if (_widget->markingMessagesRead()
+		&& (barIndex < 0 || index != barIndex)
+		&& elementIndex >= 0
+		&& elementIndex < int(elements.size())) {
+		session().data().histories().readInboxTill(
+			elements[elementIndex]->data());
+	}
+}
+
+void HistoryInner::accessibilityChildSetFocus(quintptr identity) {
+	// UIA invokes provider actions (SetFocus) on a background thread, so
+	// hop to the main thread before touching any widget state. Resolve
+	// the stable identity to its current index here (not on the
+	// background thread) so a list mutation does not move focus to
+	// another row.
+	crl::on_main(this, [=] {
+		// An explicit accessibility SetFocus is itself sufficient
+		// authorization, so we do not gate it on the screen-reader-mode
+		// detector: the UIA provider already reported success to the
+		// caller, and the detector may still be false during startup or
+		// for valid clients that are not on its allowlist.
+		const auto index = accessibilityChildIndexByIdentity(identity);
+		if (index < 0) {
+			return;
+		}
+		applyAccessibilityFocus(index, true);
+	});
+}
+
+void HistoryInner::accessibilityChildActivate(quintptr identity) {
+	// A mouse click on a message body performs no action, so Invoke
+	// mirrors the click and only takes the accessibility focus onto the
+	// row. Same background-thread hop and identity resolution as
+	// SetFocus above.
+	crl::on_main(this, [=] {
+		const auto index = accessibilityChildIndexByIdentity(identity);
+		if (index < 0) {
+			return;
+		}
+		applyAccessibilityFocus(index, true);
+	});
+}
diff --git a/Telegram/SourceFiles/history/history_inner_widget.h b/Telegram/SourceFiles/history/history_inner_widget.h
@@ -133,6 +133,12 @@ class HistoryInner
 		int row, int column) const override;
 	QString accessibilityChildSubItemValue(
 		int row, int column) const override;
+	bool accessibilityChildSupportsActions(int index) const override;
+	quintptr accessibilityChildIdentity(int index) const override;
+	int accessibilityChildIndexByIdentity(
+		quintptr identity) const override;
+	void accessibilityChildSetFocus(quintptr identity) override;
+	void accessibilityChildActivate(quintptr identity) override;
 
 	[[nodiscard]] Main::Session &session() const;
 	[[nodiscard]] not_null<Ui::ChatTheme*> theme() const {
@@ -307,6 +313,7 @@ class HistoryInner
 	void playPauseFocusedMedia();
 	void setAccessibilityFocusedItem(int index, HistoryItem *item);
 	void announceAccessibilityFocus(int index);
+	void applyAccessibilityFocus(int index, bool announceAlways);
 	[[nodiscard]] auto computeActiveColumns(int row) const
 		-> const std::vector<HistoryView::MessageSubItem> &;
 
@@ -551,6 +558,10 @@ class HistoryInner
 
 	int _accessibilityFocusedIndex = -1;
 	HistoryItem *_accessibilityFocusedItem = nullptr;
+	mutable base::flat_map<
+		not_null<const HistoryItem*>,
+		quintptr> _accessibilityIdentities;
+	mutable quintptr _accessibilityIdentityCounter = 0;
 	mutable const HistoryView::Element *_activeColumnsView = nullptr;
 	mutable std::vector<HistoryView::MessageSubItem> _activeColumns;
 
diff --git a/Telegram/SourceFiles/history/view/history_view_list_widget.cpp b/Telegram/SourceFiles/history/view/history_view_list_widget.cpp
@@ -4899,6 +4899,7 @@ void ListWidget::itemRemoved(not_null<const HistoryItem*> item) {
 	if (_accessibilityFocusedItem == item) {
 		_accessibilityFocusedItem = nullptr;
 	}
+	_accessibilityIdentities.remove(item);
 	const auto i = _views.find(item);
 	if (i == end(_views)) {
 		return;
@@ -5391,6 +5392,144 @@ void ListWidget::focusInEvent(QFocusEvent *e) {
 	});
 }
 
+bool ListWidget::accessibilityChildSupportsActions(int index) const {
+	// Every message row can be focused and activated and has a stable
+	// identity below. Tying the opt-in to a valid identity keeps the
+	// action interface off invalid indices and off the unread bar row,
+	// which has no meaningful press action.
+	return accessibilityChildIdentity(index) != 0;
+}
+
+quintptr ListWidget::accessibilityChildIdentity(int index) const {
+	// Child indices shift whenever messages are inserted or removed and
+	// the unread bar appears or goes away, so a queued action must not
+	// be dispatched by index. A raw HistoryItem pointer is not a safe
+	// token either: items are destroyed all the time and a new message
+	// can be allocated at the same address, silently rebinding a stale
+	// provider to an unrelated row (ABA). So the first request issues
+	// the item a token from a monotonic counter; itemRemoved() erases
+	// the pointer->token entry, and an item reusing the address gets a
+	// fresh token, so stale identities resolve to nothing. The unread
+	// bar row deliberately has no identity (and no action interface).
+	const auto barIndex = accessibilityUnreadBarIndex();
+	if (barIndex >= 0 && index == barIndex) {
+		return 0;
+	}
+	const auto elements = accessibleElements();
+	const auto elementIndex = (barIndex >= 0 && index > barIndex)
+		? (index - 1)
+		: index;
+	if (elementIndex < 0 || elementIndex >= int(elements.size())) {
+		return 0;
+	}
+	const auto item = elements[elementIndex]->data();
+	const auto i = _accessibilityIdentities.find(item);
+	if (i != _accessibilityIdentities.end()) {
+		return i->second;
+	}
+	const auto token = ++_accessibilityIdentityCounter;
+	_accessibilityIdentities.emplace(item, token);
+	return token;
+}
+
+int ListWidget::accessibilityChildIndexByIdentity(
+		quintptr identity) const {
+	// One pass over the elements looking each item up in the issued
+	// tokens map: only an item that was already handed out a token can
+	// match, so rows never seen by the accessibility layer just do not
+	// compare equal.
+	if (!identity) {
+		return -1;
+	}
+	const auto elements = accessibleElements();
+	const auto barIndex = accessibilityUnreadBarIndex();
+	for (auto i = 0, n = int(elements.size()); i != n; ++i) {
+		const auto j = _accessibilityIdentities.find(
+			elements[i]->data());
+		if (j != _accessibilityIdentities.end()
+			&& j->second == identity) {
+			return (barIndex >= 0 && i >= barIndex) ? (i + 1) : i;
+		}
+	}
+	return -1;
+}
+
+void ListWidget::applyAccessibilityFocus(
+		int index,
+		bool announceAlways) {
+	const auto elements = accessibleElements();
+	const auto barIndex = accessibilityUnreadBarIndex();
+	const auto elementIndex = (barIndex >= 0 && index > barIndex)
+		? (index - 1)
+		: index;
+	const auto item = (elementIndex >= 0
+		&& elementIndex < int(elements.size()))
+		? elements[elementIndex]->data().get()
+		: nullptr;
+	const auto changed = (_accessibilityFocusedIndex != index)
+		|| (_accessibilityFocusedItem != item);
+	_accessibilityFocusedIndex = index;
+	_accessibilityFocusedItem = item;
+	// Exactly one announcement: directly when the widget already has
+	// focus, via focusInEvent when keyboard focus is being taken.
+	if (hasFocus()) {
+		if (changed || announceAlways) {
+			announceAccessibilityFocus(index);
+		}
+	} else {
+		setFocus();
+	}
+	const auto rect = accessibilityChildRect(index);
+	if (!rect.isEmpty()) {
+		if (rect.top() < _visibleTop) {
+			_delegate->listScrollTo(rect.top());
+		} else if (rect.bottom() > _visibleBottom) {
+			_delegate->listScrollTo(rect.bottom()
+				- (_visibleBottom - _visibleTop));
+		}
+	}
+	if (markingMessagesRead()
+		&& (barIndex < 0 || index != barIndex)
+		&& elementIndex >= 0
+		&& elementIndex < int(elements.size())) {
+		_delegate->listMarkReadTill(elements[elementIndex]->data());
+	}
+}
+
+void ListWidget::accessibilityChildSetFocus(quintptr identity) {
+	// UIA invokes provider actions (SetFocus) on a background thread, so
+	// hop to the main thread before touching any widget state. Resolve
+	// the stable identity to its current index here (not on the
+	// background thread) so a list mutation does not move focus to
+	// another row.
+	crl::on_main(this, [=] {
+		// An explicit accessibility SetFocus is itself sufficient
+		// authorization, so we do not gate it on the screen-reader-mode
+		// detector: the UIA provider already reported success to the
+		// caller, and the detector may still be false during startup or
+		// for valid clients that are not on its allowlist.
+		const auto index = accessibilityChildIndexByIdentity(identity);
+		if (index < 0) {
+			return;
+		}
+		applyAccessibilityFocus(index, true);
+	});
+}
+
+void ListWidget::accessibilityChildActivate(quintptr identity) {
+	// A mouse click on a message body performs no action, so Invoke
+	// mirrors the click and only takes the accessibility focus onto the
+	// row. Same background-thread hop and identity resolution as
+	// SetFocus above.
+	crl::on_main(this, [=] {
+		const auto index = accessibilityChildIndexByIdentity(identity);
+		if (index < 0) {
+			return;
+		}
+		applyAccessibilityFocus(index, true);
+	});
+}
+
 void ConfirmDeleteSelectedItems(not_null<ListWidget*> widget) {
 	const auto items = widget->getSelectedItems();
 	if (items.empty()) {
diff --git a/Telegram/SourceFiles/history/view/history_view_list_widget.h b/Telegram/SourceFiles/history/view/history_view_list_widget.h
@@ -507,6 +507,12 @@ class ListWidget final
 		int row, int column) const override;
 	QString accessibilityChildSubItemValue(
 		int row, int column) const override;
+	bool accessibilityChildSupportsActions(int index) const override;
+	quintptr accessibilityChildIdentity(int index) const override;
+	int accessibilityChildIndexByIdentity(
+		quintptr identity) const override;
+	void accessibilityChildSetFocus(quintptr identity) override;
+	void accessibilityChildActivate(quintptr identity) override;
 
 	~ListWidget();
 
@@ -550,6 +556,7 @@ class ListWidget final
 	void playPauseFocusedMedia();
 	void setAccessibilityFocusedItem(int index, HistoryItem *item);
 	void announceAccessibilityFocus(int index);
+	void applyAccessibilityFocus(int index, bool announceAlways);
 	[[nodiscard]] auto computeActiveColumns(int row) const
 		-> const std::vector<HistoryView::MessageSubItem> &;
 
@@ -931,6 +938,10 @@ class ListWidget final
 
 	int _accessibilityFocusedIndex = -1;
 	HistoryItem *_accessibilityFocusedItem = nullptr;
+	mutable base::flat_map<
+		not_null<const HistoryItem*>,
+		quintptr> _accessibilityIdentities;
+	mutable quintptr _accessibilityIdentityCounter = 0;
 	mutable const HistoryView::Element *_activeColumnsView = nullptr;
 	mutable std::vector<HistoryView::MessageSubItem> _activeColumns;
 
