gecko-dev/accessible/base/FocusManager.h
James Teh 67fb859dcb Bug 1190882: If the focused accessible is removed from the tree, fire a11y focus on the document. r=eeejay
If the DOM focus is removed before something else is focused, the document gets DOM focus, but no blur event is fired (bug 559561).
This means that no a11y focus event is fired, so clients aren't notified.
This is particularly problematic for screen readers when dismissing some ARIA dialogs, as the screen reader doesn't know that focus has returned to the top level document.

Differential Revision: https://phabricator.services.mozilla.com/D31024

--HG--
extra : moz-landing-system : lando
2019-05-15 00:31:16 +00:00

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3.6 KiB
C++

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_a11y_FocusManager_h_
#define mozilla_a11y_FocusManager_h_
#include "mozilla/RefPtr.h"
class nsINode;
class nsISupports;
namespace mozilla {
namespace dom {
class Document;
}
namespace a11y {
class AccEvent;
class Accessible;
class DocAccessible;
/**
* Manage the accessible focus. Used to fire and process accessible events.
*/
class FocusManager {
public:
virtual ~FocusManager();
/**
* Return a focused accessible.
*/
Accessible* FocusedAccessible() const;
/**
* Return true if given accessible is focused.
*/
bool IsFocused(const Accessible* aAccessible) const;
/**
* Return true if the given accessible is an active item, i.e. an item that
* is current within the active widget.
*/
inline bool IsActiveItem(const Accessible* aAccessible) {
return aAccessible == mActiveItem;
}
/**
* Return DOM node having DOM focus.
*/
nsINode* FocusedDOMNode() const;
/**
* Return true if given DOM node has DOM focus.
*/
inline bool HasDOMFocus(const nsINode* aNode) const {
return aNode == FocusedDOMNode();
}
/**
* Return true if focused accessible is within the given container.
*/
bool IsFocusWithin(const Accessible* aContainer) const;
/**
* Return whether the given accessible is focused or contains the focus or
* contained by focused accessible.
*/
enum FocusDisposition { eNone, eFocused, eContainsFocus, eContainedByFocus };
FocusDisposition IsInOrContainsFocus(const Accessible* aAccessible) const;
/**
* Return true if the given accessible was the last accessible focused.
* This is useful to detect the case where the last focused accessible was
* removed before something else was focused. This can happen in one of two
* ways:
* 1. The DOM focus was removed. DOM doesn't fire a blur event when this
* happens; see bug 559561.
* 2. The accessibility focus was an active item (e.g. aria-activedescendant)
* and that item was removed.
*/
bool WasLastFocused(const Accessible* aAccessible) const;
//////////////////////////////////////////////////////////////////////////////
// Focus notifications and processing (don't use until you know what you do).
/**
* Called when DOM focus event is fired.
*/
void NotifyOfDOMFocus(nsISupports* aTarget);
/**
* Called when DOM blur event is fired.
*/
void NotifyOfDOMBlur(nsISupports* aTarget);
/**
* Called when active item is changed. Note: must be called when accessible
* tree is up to date.
*/
void ActiveItemChanged(Accessible* aItem, bool aCheckIfActive = true);
/**
* Dispatch delayed focus event for the current focus accessible.
*/
void ForceFocusEvent();
/**
* Dispatch delayed focus event for the given target.
*/
void DispatchFocusEvent(DocAccessible* aDocument, Accessible* aTarget);
/**
* Process DOM focus notification.
*/
void ProcessDOMFocus(nsINode* aTarget);
/**
* Process the delayed accessible event.
* do.
*/
void ProcessFocusEvent(AccEvent* aEvent);
protected:
FocusManager();
private:
FocusManager(const FocusManager&);
FocusManager& operator=(const FocusManager&);
/**
* Return DOM document having DOM focus.
*/
dom::Document* FocusedDOMDocument() const;
private:
RefPtr<Accessible> mActiveItem;
RefPtr<Accessible> mLastFocus;
RefPtr<Accessible> mActiveARIAMenubar;
};
} // namespace a11y
} // namespace mozilla
#endif