gecko-dev/accessible/base/nsAccessiblePivot.h
2019-09-18 22:23:58 +00:00

139 lines
3.8 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* 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 _nsAccessiblePivot_H_
#define _nsAccessiblePivot_H_
#include "nsIAccessiblePivot.h"
#include "Accessible-inl.h"
#include "nsTObserverArray.h"
#include "nsCycleCollectionParticipant.h"
#include "mozilla/Attributes.h"
class RuleCache;
/**
* Class represents an accessible pivot.
*/
class nsAccessiblePivot final : public nsIAccessiblePivot {
public:
typedef mozilla::a11y::Accessible Accessible;
explicit nsAccessiblePivot(Accessible* aRoot);
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsAccessiblePivot,
nsIAccessiblePivot)
NS_DECL_NSIACCESSIBLEPIVOT
/*
* A simple getter for the pivot's position.
*/
Accessible* Position() { return mPosition; }
int32_t StartOffset() { return mStartOffset; }
int32_t EndOffset() { return mEndOffset; }
private:
~nsAccessiblePivot();
nsAccessiblePivot() = delete;
nsAccessiblePivot(const nsAccessiblePivot&) = delete;
void operator=(const nsAccessiblePivot&) = delete;
/*
* Notify all observers on a pivot change. Return true if it has changed and
* observers have been notified.
*/
bool NotifyOfPivotChange(Accessible* aOldAccessible, int32_t aOldStart,
int32_t aOldEnd, PivotMoveReason aReason,
TextBoundaryType aBoundaryType,
bool aIsFromUserInput);
/*
* Check to see that the given accessible is a descendant of given ancestor
*/
bool IsDescendantOf(Accessible* aAccessible, Accessible* aAncestor);
/*
* Search in preorder for the first accessible to match the rule.
*/
Accessible* SearchForward(Accessible* aAccessible,
nsIAccessibleTraversalRule* aRule,
bool aSearchCurrent, nsresult* aResult);
/*
* Reverse search in preorder for the first accessible to match the rule.
*/
Accessible* SearchBackward(Accessible* aAccessible,
nsIAccessibleTraversalRule* aRule,
bool aSearchCurrent, nsresult* aResult);
/*
* Get the effective root for this pivot, either the true root or modal root.
*/
Accessible* GetActiveRoot() const {
if (mModalRoot) {
NS_ENSURE_FALSE(mModalRoot->IsDefunct(), mRoot);
return mModalRoot;
}
return mRoot;
}
/*
* Update the pivot, and notify observers. Return true if it moved.
*/
bool MovePivotInternal(Accessible* aPosition, PivotMoveReason aReason,
bool aIsFromUserInput);
/*
* Get initial node we should start a search from with a given rule.
*
* When we do a move operation from one position to another,
* the initial position can be inside of a subtree that is ignored by
* the given rule. We need to step out of the ignored subtree and start
* the search from there.
*
*/
Accessible* AdjustStartPosition(Accessible* aAccessible, RuleCache& aCache,
uint16_t* aFilterResult, nsresult* aResult);
/*
* The root accessible.
*/
RefPtr<Accessible> mRoot;
/*
* The temporary modal root accessible.
*/
RefPtr<Accessible> mModalRoot;
/*
* The current pivot position.
*/
RefPtr<Accessible> mPosition;
/*
* The text start offset ofthe pivot.
*/
int32_t mStartOffset;
/*
* The text end offset ofthe pivot.
*/
int32_t mEndOffset;
/*
* The list of pivot-changed observers.
*/
nsTObserverArray<nsCOMPtr<nsIAccessiblePivotObserver> > mObservers;
};
#endif