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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_Pivot_h_
#define mozilla_a11y_Pivot_h_
#include <stdint.h>
#include "Role.h"
#include "mozilla/dom/ChildIterator.h"
namespace mozilla {
namespace a11y {
class LocalAccessible;
class HyperTextAccessible;
class DocAccessible;
class Accessible;
class PivotRule {
public:
// A filtering function that returns a bitmask from
// nsIAccessibleTraversalRule: FILTER_IGNORE (0x0): Don't match this
// accessible. FILTER_MATCH (0x1): Match this accessible FILTER_IGNORE_SUBTREE
// (0x2): Ignore accessible's subtree.
virtual uint16_t Match(Accessible* aAcc) = 0;
};
// The Pivot class is used for searching for accessible nodes in a given subtree
// with a given criteria. Since it only holds a weak reference to the root,
// this class is meant to be used primarily on the stack.
class Pivot final {
public:
explicit Pivot(Accessible* aRoot);
Pivot() = delete;
Pivot(const Pivot&) = delete;
Pivot& operator=(const Pivot&) = delete;
~Pivot();
// Return the next accessible after aAnchor in pre-order that matches the
// given rule. If aIncludeStart, return aAnchor if it matches the rule.
Accessible* Next(Accessible* aAnchor, PivotRule& aRule,
bool aIncludeStart = false);
// Return the previous accessible before aAnchor in pre-order that matches the
// given rule. If aIncludeStart, return aAnchor if it matches the rule.
Accessible* Prev(Accessible* aAnchor, PivotRule& aRule,
bool aIncludeStart = false);
// Return the first accessible within the root that matches the pivot rule.
Accessible* First(PivotRule& aRule);
// Return the last accessible within the root that matches the pivot rule.
Accessible* Last(PivotRule& aRule);
// Return the next range of text according to the boundary type.
LocalAccessible* NextText(LocalAccessible* aAnchor, int32_t* aStartOffset,
int32_t* aEndOffset, int32_t aBoundaryType);
// Return the previous range of text according to the boundary type.
LocalAccessible* PrevText(LocalAccessible* aAnchor, int32_t* aStartOffset,
int32_t* aEndOffset, int32_t aBoundaryType);
// Return the accessible at the given screen coordinate if it matches the
// pivot rule.
Accessible* AtPoint(int32_t aX, int32_t aY, PivotRule& aRule);
private:
Accessible* AdjustStartPosition(Accessible* aAnchor, PivotRule& aRule,
uint16_t* aFilterResult);
// Search in preorder for the first accessible to match the rule.
Accessible* SearchForward(Accessible* aAnchor, PivotRule& aRule,
bool aSearchCurrent);
// Reverse search in preorder for the first accessible to match the rule.
Accessible* SearchBackward(Accessible* aAnchor, PivotRule& aRule,
bool aSearchCurrent);
// Search in preorder for the first text accessible.
HyperTextAccessible* SearchForText(LocalAccessible* aAnchor, bool aBackward);
Accessible* mRoot;
};
/**
* This rule matches accessibles on a given role, filtering out non-direct
* descendants if necessary.
*/
class PivotRoleRule : public PivotRule {
public:
explicit PivotRoleRule(role aRole);
explicit PivotRoleRule(role aRole, Accessible* aDirectDescendantsFrom);
virtual uint16_t Match(Accessible* aAcc) override;
protected:
role mRole;
Accessible* mDirectDescendantsFrom;
};
/**
* This rule matches any local LocalAccessible (i.e. not RemoteAccessible) in
* the same document as the anchor. That is, it includes any descendant
* OuterDocAccessible, but not its descendants.
*/
class LocalAccInSameDocRule : public PivotRule {
public:
virtual uint16_t Match(Accessible* aAcc) override;
};
} // namespace a11y
} // namespace mozilla
#endif // mozilla_a11y_Pivot_h_