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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_ACCESSIBILITY_PLATFORM_ONE_SHOT_ACCESSIBILITY_TREE_SEARCH_H_
#define UI_ACCESSIBILITY_PLATFORM_ONE_SHOT_ACCESSIBILITY_TREE_SEARCH_H_
#include <stddef.h>
#include <string>
#include <vector>
#include "base/component_export.h"
#include "base/memory/raw_ptr.h"
namespace ui {
class BrowserAccessibilityManager;
class BrowserAccessibility;
// A function that returns whether or not a given node matches, given the
// start element of the search as an optional comparator.
typedef bool (*AccessibilityMatchPredicate)(
BrowserAccessibility* start_element,
BrowserAccessibility* this_element);
#define DECLARE_ACCESSIBILITY_PREDICATE(PredicateName) \
COMPONENT_EXPORT(AX_PLATFORM) bool PredicateName( \
BrowserAccessibility* start_element, \
BrowserAccessibility* this_element)
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityArticlePredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityBlockquotePredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityButtonPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityCheckboxPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityComboboxPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityControlPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityFocusablePredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityFramePredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityGraphicPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityH1Predicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityH2Predicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityH3Predicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityH4Predicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityH5Predicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityH6Predicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityHeadingPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityHeadingSameLevelPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityLandmarkPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityLinkPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityListPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityListItemPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityLiveRegionPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityMainPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityMediaPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityParagraphPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityRadioButtonPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityRadioGroupPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilitySectionPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityTablePredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityTextfieldPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityTextStyleBoldPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityTextStyleItalicPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityTextStyleUnderlinePredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityTreePredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityUnvisitedLinkPredicate);
DECLARE_ACCESSIBILITY_PREDICATE(AccessibilityVisitedLinkPredicate);
#undef DECLARE_ACCESSIBILITY_PREDICATE
// This class provides an interface for searching the accessibility tree from
// a given starting node, with a few built-in options and allowing an arbitrary
// number of predicates that can be used to restrict the search.
//
// This class is meant to perform one search. Initialize it, then iterate
// over the matches, and then delete it.
//
// This class stores raw pointers to the matches in the tree! Don't keep this
// object around if the tree is mutating.
class COMPONENT_EXPORT(AX_PLATFORM) OneShotAccessibilityTreeSearch final {
public:
enum Direction { FORWARDS, BACKWARDS };
const int UNLIMITED_RESULTS = -1;
// The node passed in |scope| determines the scope of results returned -
// they will all be within the subtree of the *parent* of |scope| - in other
// words, siblings of |scope| and their descendants.
explicit OneShotAccessibilityTreeSearch(BrowserAccessibility* scope);
OneShotAccessibilityTreeSearch(const OneShotAccessibilityTreeSearch&) =
delete;
OneShotAccessibilityTreeSearch& operator=(
const OneShotAccessibilityTreeSearch&) = delete;
~OneShotAccessibilityTreeSearch();
//
// Search parameters. All of these are optional.
//
// Sets the node where the search starts. The first potential match will
// be the one immediately following this one. This node will be used as
// the first arguement to any predicates.
//
// If not specified, |scope| will be used.
void SetStartNode(BrowserAccessibility* start_node);
// Search forwards or backwards in an in-order traversal of the tree.
void SetDirection(Direction direction);
// Set the maximum number of results, or UNLIMITED_RESULTS
// for no limit (default).
void SetResultLimit(int result_limit);
// If true, only searches children of |start_node| and doesn't
// recurse.
void SetImmediateDescendantsOnly(bool immediate_descendants_only);
// If true, wraps to the last element.
void SetCanWrapToLastElement(bool can_wrap_to_last_element);
// If true, only considers nodes that aren't offscreen.
// Programmatically hidden elements are always skipped.
void SetOnscreenOnly(bool onscreen_only);
// Restricts the matches to only nodes where |text| is found as a
// substring of any of that node's accessible text, including its
// name, description, or value. Case-insensitive.
void SetSearchText(const std::string& text);
// Restricts the matches to only those that satisfy at least one of the
// predicates.
void AddPredicate(AccessibilityMatchPredicate predicate);
//
// Calling either of these executes the search.
//
size_t CountMatches();
BrowserAccessibility* GetMatchAtIndex(size_t index);
private:
void Search();
void SearchByWalkingTree();
void SearchByIteratingOverChildren();
bool Matches(BrowserAccessibility* node);
raw_ptr<BrowserAccessibilityManager> tree_;
raw_ptr<BrowserAccessibility> scope_node_;
raw_ptr<BrowserAccessibility> start_node_;
Direction direction_;
int result_limit_;
bool immediate_descendants_only_;
bool can_wrap_to_last_element_;
bool onscreen_only_;
std::string search_text_;
std::vector<AccessibilityMatchPredicate> predicates_;
std::vector<raw_ptr<BrowserAccessibility, VectorExperimental>> matches_;
bool did_search_;
};
} // namespace ui
#endif // UI_ACCESSIBILITY_PLATFORM_ONE_SHOT_ACCESSIBILITY_TREE_SEARCH_H_
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