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chromium / chromium / src.git / main / . / ui / accessibility / ax_node.h
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// Copyright 2013 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_AX_NODE_H_
#define UI_ACCESSIBILITY_AX_NODE_H_
#include <stdint.h>
#include <iterator>
#include <memory>
#include <optional>
#include <ostream>
#include <string>
#include <utility>
#include <vector>
#include "base/containers/queue.h"
#include "base/containers/stack.h"
#include "base/memory/raw_ptr.h"
#include "build/build_config.h"
#include "third_party/skia/include/core/SkColor.h"
#include "ui/accessibility/ax_common.h"
#include "ui/accessibility/ax_export.h"
#include "ui/accessibility/ax_hypertext.h"
#include "ui/accessibility/ax_node_data.h"
#include "ui/accessibility/ax_text_attributes.h"
#include "ui/accessibility/ax_tree_id.h"
#include "ui/gfx/geometry/rect_f.h"
namespace ui {
class AXComputedNodeData;
class AXSelection;
class AXTableInfo;
class AXTreeManager;
struct AXLanguageInfo;
class AXTree;
// This class is used to represent a node in an accessibility tree (`AXTree`).
class AX_EXPORT AXNode final {
public:
// Replacement character used to represent an embedded (or, additionally for
// text navigation, an empty) object. Part of the Unicode Standard.
//
// On some platforms, most objects are represented in the text of their
// parents with a special "embedded object character" and not with their
// actual text contents. Also on the same platforms, if a node has only
// ignored descendants, i.e., it appears to be empty to assistive software, we
// need to treat it as a character and a word boundary.
static constexpr char kEmbeddedObjectCharacterUTF8[] = "\xEF\xBF\xBC";
static constexpr char16_t kEmbeddedObjectCharacterUTF16[] = u"\xFFFC";
// We compute the embedded characters' length instead of manually typing it in
// order to avoid the variable pairs getting out of sync in a future update.
static constexpr int kEmbeddedObjectCharacterLengthUTF8 =
std::char_traits<char>::length(kEmbeddedObjectCharacterUTF8);
static constexpr int kEmbeddedObjectCharacterLengthUTF16 =
std::char_traits<char16_t>::length(kEmbeddedObjectCharacterUTF16);
// Default values must be consistent with AXNodeData.
static constexpr bool kDefaultBoolValue = AXNodeData::kDefaultBoolValue;
static constexpr int kDefaultIntValue = AXNodeData::kDefaultIntValue;
static constexpr float kDefaultFloatValue = AXNodeData::kDefaultFloatValue;
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
class ChildIteratorBase {
public:
using iterator_category = std::bidirectional_iterator_tag;
using difference_type = int;
using value_type = NodeType;
using pointer = NodeType*;
using reference = NodeType&;
ChildIteratorBase(const NodeType* parent, NodeType* child);
ChildIteratorBase(const ChildIteratorBase& it);
~ChildIteratorBase() = default;
friend bool operator==(const ChildIteratorBase&,
const ChildIteratorBase&) = default;
ChildIteratorBase& operator++();
ChildIteratorBase& operator--();
NodeType* get() const;
NodeType& operator*() const;
NodeType* operator->() const;
protected:
raw_ptr<const NodeType> parent_;
raw_ptr<NodeType, DanglingUntriaged> child_;
};
// The constructor requires a parent, id, and index in parent, but
// the data is not required. After initialization, only index_in_parent
// and unignored_index_in_parent is allowed to change, the others are
// guaranteed to never change.
AXNode(AXTree* tree,
AXNode* parent,
AXNodeID id,
size_t index_in_parent,
size_t unignored_index_in_parent = 0u);
~AXNode();
// Accessors.
AXTree* tree() const { return tree_; }
AXNodeID id() const { return data_.id; }
const AXNodeData& data() const { return data_; }
// Returns ownership of |data_| to the caller; effectively clearing |data_|.
AXNodeData&& TakeData();
//
// Methods for walking the tree.
//
// These come in four flavors: Methods that walk all the nodes, methods that
// walk only the unignored nodes (effectively re-structuring the tree to
// remove all ignored nodes), and another two variants that do the above plus
// cross tree boundaries, effectively stiching together all accessibility
// trees that are part of the same webpage, PDF or window into a large global
// tree.
const std::vector<raw_ptr<AXNode, VectorExperimental>>& GetAllChildren()
const;
size_t GetChildCount() const;
#if AX_FAIL_FAST_BUILD()
size_t GetSubtreeCount() const;
#endif
size_t GetChildCountCrossingTreeBoundary() const;
size_t GetUnignoredChildCount() const;
size_t GetUnignoredChildCountCrossingTreeBoundary() const;
AXNode* GetChildAtIndex(size_t index) const;
AXNode* GetChildAtIndexCrossingTreeBoundary(size_t index) const;
AXNode* GetUnignoredChildAtIndex(size_t index) const;
AXNode* GetUnignoredChildAtIndexCrossingTreeBoundary(size_t index) const;
AXNode* GetParent() const;
AXNode* GetParentCrossingTreeBoundary() const;
AXNode* GetUnignoredParent() const;
AXNode* GetUnignoredParentCrossingTreeBoundary() const;
base::queue<AXNode*> GetAncestorsCrossingTreeBoundaryAsQueue() const;
base::stack<AXNode*> GetAncestorsCrossingTreeBoundaryAsStack() const;
size_t GetIndexInParent() const;
size_t GetUnignoredIndexInParent() const;
AXNode* GetFirstChild() const;
AXNode* GetFirstChildCrossingTreeBoundary() const;
AXNode* GetFirstUnignoredChild() const;
AXNode* GetFirstUnignoredChildCrossingTreeBoundary() const;
AXNode* GetLastChild() const;
AXNode* GetLastChildCrossingTreeBoundary() const;
AXNode* GetLastUnignoredChild() const;
AXNode* GetLastUnignoredChildCrossingTreeBoundary() const;
AXNode* GetDeepestFirstDescendant() const;
AXNode* GetDeepestFirstDescendantCrossingTreeBoundary() const;
AXNode* GetDeepestFirstUnignoredDescendant() const;
AXNode* GetDeepestFirstUnignoredDescendantCrossingTreeBoundary() const;
AXNode* GetDeepestLastDescendant() const;
AXNode* GetDeepestLastDescendantCrossingTreeBoundary() const;
AXNode* GetDeepestLastUnignoredDescendant() const;
AXNode* GetDeepestLastUnignoredDescendantCrossingTreeBoundary() const;
AXNode* GetNextSibling() const;
AXNode* GetNextUnignoredSibling() const;
AXNode* GetPreviousSibling() const;
AXNode* GetPreviousUnignoredSibling() const;
// Traverse the tree in depth-first pre-order.
AXNode* GetNextUnignoredInTreeOrder() const;
AXNode* GetPreviousUnignoredInTreeOrder() const;
//
// Deprecated methods for walking the tree.
//
const std::vector<raw_ptr<AXNode, VectorExperimental>>& children() const {
return children_;
}
AXNode* parent() const { return parent_; }
size_t index_in_parent() const { return index_in_parent_; }
//
// Iterators for walking the tree in depth-first pre-order.
//
using AllChildIterator = ChildIteratorBase<AXNode,
&AXNode::GetNextSibling,
&AXNode::GetPreviousSibling,
&AXNode::GetFirstChild,
&AXNode::GetLastChild>;
AllChildIterator AllChildrenBegin() const;
AllChildIterator AllChildrenEnd() const;
using AllChildCrossingTreeBoundaryIterator =
ChildIteratorBase<AXNode,
&AXNode::GetNextSibling,
&AXNode::GetPreviousSibling,
&AXNode::GetFirstChildCrossingTreeBoundary,
&AXNode::GetLastChildCrossingTreeBoundary>;
AllChildCrossingTreeBoundaryIterator AllChildrenCrossingTreeBoundaryBegin()
const;
AllChildCrossingTreeBoundaryIterator AllChildrenCrossingTreeBoundaryEnd()
const;
using UnignoredChildIterator =
ChildIteratorBase<AXNode,
&AXNode::GetNextUnignoredSibling,
&AXNode::GetPreviousUnignoredSibling,
&AXNode::GetFirstUnignoredChild,
&AXNode::GetLastUnignoredChild>;
UnignoredChildIterator UnignoredChildrenBegin() const;
UnignoredChildIterator UnignoredChildrenEnd() const;
using UnignoredChildCrossingTreeBoundaryIterator =
ChildIteratorBase<AXNode,
&AXNode::GetNextUnignoredSibling,
&AXNode::GetPreviousUnignoredSibling,
&AXNode::GetFirstUnignoredChildCrossingTreeBoundary,
&AXNode::GetLastUnignoredChildCrossingTreeBoundary>;
UnignoredChildCrossingTreeBoundaryIterator
UnignoredChildrenCrossingTreeBoundaryBegin() const;
UnignoredChildCrossingTreeBoundaryIterator
UnignoredChildrenCrossingTreeBoundaryEnd() const;
// Returns true if this is a node on which accessibility events make sense to
// be fired. Events are not needed on nodes that will, for example, never
// appear in a tree that is visible to assistive software, as there will be no
// software to handle the event on the other end.
bool CanFireEvents() const;
AXNode* GetLowestCommonAncestor(const AXNode& other);
// Returns an optional integer indicating the logical order of this node
// compared to another node, or returns an empty optional if the nodes are not
// comparable. Nodes are not comparable if they do not share a common
// ancestor.
//
// 0: if this node is logically equivalent to the other node.
// <0: if this node is logically less than the other node.
// >0: if this node is logically greater than the other node.
//
// Another way to look at the nodes' relative positions/logical orders is that
// they are equivalent to pre-order traversal of the tree. If we pre-order
// traverse from the root, the node that we visited earlier is always going to
// be before (logically less) the node we visit later.
std::optional<int> CompareTo(const AXNode& other) const;
bool IsDataValid() const { return data_.id != kInvalidAXNodeID; }
// Returns true if the node has any of the text related roles, including
// kStaticText, kInlineTextBox and kListMarker (for Legacy Layout). Does not
// include any text field roles.
bool IsText() const;
// Returns true if the node has any line break related roles or is the child
// of a node with line break related roles.
bool IsLineBreak() const;
// Set the node's accessibility data. This may be done during initialization
// or later when the node data changes.
void SetData(const AXNodeData& src);
// Update this node's location. This is separate from |SetData| just because
// changing only the location is common and should be more efficient than
// re-copying all of the data.
//
// The node's location is stored as a relative bounding box, the ID of
// the element it's relative to, and an optional transformation matrix.
// See ax_node_data.h for details.
void SetLocation(AXNodeID offset_container_id,
const gfx::RectF& location,
gfx::Transform* transform);
// Update this node's scroll x and y. This is separate from |SetData| just
// because changing only the scroll info is common and should be more
// efficient than re-copying all of the data.
void SetScrollInfo(const int& scroll_x, const int& scroll_y);
void GetScrollInfo(int* scroll_x, int* scroll_y) const;
// Set the index in parent, for example if siblings were inserted or deleted.
void SetIndexInParent(size_t index_in_parent);
// When the node's `IsIgnored()` value changes, updates the cached values for
// the unignored index in parent and the unignored child count.
void UpdateUnignoredCachedValues();
// Swap the internal children vector with |children|. This instance
// now owns all of the passed children.
void SwapChildren(std::vector<raw_ptr<AXNode, VectorExperimental>>* children);
// Returns true if this node is equal to or a descendant of |ancestor|.
bool IsDescendantOf(const AXNode* ancestor) const;
bool IsDescendantOfCrossingTreeBoundary(const AXNode* ancestor) const;
// If the color is transparent, blends with the ancestor's color.
// Note that this is imperfect; it won't work if a node is absolute-
// positioned outside of its ancestor. However, it handles the most
// common cases.
SkColor ComputeColor() const;
SkColor ComputeBackgroundColor() const;
AXTreeManager* GetManager() const;
//
// Methods for accessing caret and selection information.
//
// Returns true if the caret is visible or there is an active selection inside
// this node.
bool HasVisibleCaretOrSelection() const;
// Gets the current selection from the accessibility tree.
AXSelection GetSelection() const;
// Gets the unignored selection from the accessibility tree, meaning the
// selection whose endpoints are on unignored nodes. (An "ignored" node is a
// node that is not exposed to platform APIs: See `IsIgnored`.)
AXSelection GetUnignoredSelection() const;
//
// Methods for accessing accessibility attributes including attributes that
// are computed on the browser side. (See `AXNodeData` and
// `AXComputedNodeData` for more information.)
//
// Please prefer using the methods in this class for retrieving attributes, as
// computed attributes would be automatically returned if available.
// Requesting the computed value for an attribute that cannot be computed
// triggers a DCHECK failure. All Get...Attribute methods in this class do
// the appropriate verification before requesting a computed attribute value.
//
// Each of the Get...Attribute methods returns a default value if not set.
// The Has...Attribute methods can be used to disambiguate a missing value
// from a default value. The default values are 0 for numerical attributes,
// an empty string for string attributes, an empty list for list valued
// attributes, and false for boolean attributes.
//
// Example:
//
// const std::string& value =
// GetStringAttribute(ax::mojom::StringAttribute::kValue);
// if (!value.empty() ||
// HasStringAttribute(ax::mojom::StringAttribute::kValue)) {
// // Handle explicitly set attribute even if an empty string.
// }
//
// Unless specifically needing a UTF16 string, it is generally advisable to
// use UTF8 strings, since these are fetched as a constant reference, whereas
// the UTF16 versions are converted from their UTF8 counterparts on demand.
//
// An explicitly set attribute may disagree with the computed value. The
// Get..Attribute methods return the explicitly set value rather than the
// computed value in this case.
//
ax::mojom::Role GetRole() const { return data().role; }
bool HasBoolAttribute(ax::mojom::BoolAttribute attribute) const {
return data().HasBoolAttribute(attribute);
}
bool GetBoolAttribute(ax::mojom::BoolAttribute attribute) const {
return data().GetBoolAttribute(attribute);
}
bool HasFloatAttribute(ax::mojom::FloatAttribute attribute) const {
return data().HasFloatAttribute(attribute);
}
float GetFloatAttribute(ax::mojom::FloatAttribute attribute) const {
return data().GetFloatAttribute(attribute);
}
const std::vector<std::pair<ax::mojom::IntAttribute, int32_t>>&
GetIntAttributes() const {
return data().int_attributes;
}
bool HasIntAttribute(ax::mojom::IntAttribute attribute) const;
bool CanComputeIntAttribute(ax::mojom::IntAttribute attribute) const;
int GetIntAttribute(ax::mojom::IntAttribute attribute) const;
const std::vector<std::pair<ax::mojom::StringAttribute, std::string>>&
GetStringAttributes() const {
return data().string_attributes;
}
bool HasStringAttribute(ax::mojom::StringAttribute attribute) const;
bool CanComputeStringAttribute(ax::mojom::StringAttribute attribute) const;
const std::string& GetStringAttribute(
ax::mojom::StringAttribute attribute) const;
std::u16string GetString16Attribute(
ax::mojom::StringAttribute attribute) const;
bool HasInheritedStringAttribute(ax::mojom::StringAttribute attribute) const;
const std::string& GetInheritedStringAttribute(
ax::mojom::StringAttribute attribute) const;
std::u16string GetInheritedString16Attribute(
ax::mojom::StringAttribute attribute) const;
const std::vector<
std::pair<ax::mojom::IntListAttribute, std::vector<int32_t>>>&
GetIntListAttributes() const {
return data().intlist_attributes;
}
bool HasIntListAttribute(ax::mojom::IntListAttribute attribute) const;
bool CanComputeIntListAttribute(ax::mojom::IntListAttribute attribute) const;
const std::vector<int32_t>& GetIntListAttribute(
ax::mojom::IntListAttribute attribute) const;
bool HasStringListAttribute(ax::mojom::StringListAttribute attribute) const {
return data().HasStringListAttribute(attribute);
}
const std::vector<std::string>& GetStringListAttribute(
ax::mojom::StringListAttribute attribute) const {
return data().GetStringListAttribute(attribute);
}
const base::StringPairs& GetHtmlAttributes() const {
return data().html_attributes;
}
AXTextAttributes GetTextAttributes() const {
return data().GetTextAttributes();
}
bool HasState(ax::mojom::State state) const { return data().HasState(state); }
ax::mojom::State GetState() const {
return static_cast<ax::mojom::State>(data().state);
}
bool HasAction(ax::mojom::Action action) const {
return data().HasAction(action);
}
bool HasTextStyle(ax::mojom::TextStyle text_style) const {
return data().HasTextStyle(text_style);
}
ax::mojom::NameFrom GetNameFrom() const { return data().GetNameFrom(); }
ax::mojom::DescriptionFrom GetDescriptionFrom() const {
return data().GetDescriptionFrom();
}
ax::mojom::InvalidState GetInvalidState() const {
return data().GetInvalidState();
}
// Return the hierarchical level if supported.
std::optional<int> GetHierarchicalLevel() const;
// PosInSet and SetSize public methods.
bool IsOrderedSetItem() const;
bool IsOrderedSet() const;
std::optional<int> GetPosInSet() const;
std::optional<int> GetSetSize() const;
// Helpers for GetPosInSet and GetSetSize.
// Returns true if the role of ordered set matches the role of item.
// Returns false otherwise.
bool SetRoleMatchesItemRole(const AXNode* ordered_set) const;
// Container objects that should be ignored for computing PosInSet and SetSize
// for ordered sets.
bool IsIgnoredContainerForOrderedSet() const;
// Helper functions that returns true when we are on a row/row group inside of
// a tree grid. Also works for rows that are part of a row group inside a tree
// grid. Returns false otherwise.
bool IsRowInTreeGrid(const AXNode* ordered_set) const;
bool IsRowGroupInTreeGrid() const;
// Returns the accessible name for this node. This could have originated from
// e.g. an onscreen label, or an ARIA label.
const std::string& GetNameUTF8() const;
std::u16string GetNameUTF16() const;
// If this node is a leaf, returns the text content of this node. This is
// equivalent to its visible accessible name. Otherwise, if this node is not a
// leaf, represents every non-textual child node with a special "embedded
// object character", and every textual child node with its text content.
// Textual nodes include e.g. static text and white space.
//
// This is how displayed text and embedded objects are represented in
// ATK and IAccessible2 APIs.
//
// TODO(nektar): Consider changing the return value to std::string.
const std::u16string& GetHypertext() const;
// Temporary accessor methods until hypertext is fully migrated to this class.
// Hypertext won't eventually need to be accessed outside this class.
const std::map<int, int>& GetHypertextOffsetToHyperlinkChildIndex() const;
// Returns the text that is found inside this node and all its descendants;
// including text found in embedded objects.
//
// Only text displayed on screen is included. Text from ARIA and HTML
// attributes that is either not displayed on screen, or outside this node, is
// not returned.
//
// Does not take into account line breaks that have been introduced by layout.
// For example, in the Web context, "A<div>B</div>C" would produce "ABC".
const std::string& GetTextContentUTF8() const;
const std::u16string& GetTextContentUTF16() const;
// Returns the length of the text (in code units) that is found inside
// this node and all its descendants; including text found in embedded
// objects.
//
// Only text displayed on screen is counted. Text from ARIA and HTML
// attributes that is either not displayed on screen, or outside this node, is
// not included.
//
// The length of the text is either in UTF8 or UTF16 code units, not in
// grapheme clusters.
int GetTextContentLengthUTF8() const;
int GetTextContentLengthUTF16() const;
// Returns the smallest bounding box that can enclose the given range of
// characters in the node's text contents. The bounding box is relative to
// this node's coordinate system as specified in
// `AXNodeData::relative_bounds`.
//
// Note that `start_offset` and `end_offset` are in UTF16 code units, not in
// grapheme clusters. For example, the following Hindi text
// u"\x0939\x093F\x0928\x094D\x0926\x0940" consists of two glyphs and has
// character offsets {40, 40, 59, 59, 59, 59} since the first glyph is
// represented by 2 code units in UTF16 and the second by 4 code units.
gfx::RectF GetTextContentRangeBoundsUTF16(int start_offset,
int end_offset) const;
// Returns a string representing the language code.
//
// This will consider the language declared in the DOM, and may eventually
// attempt to automatically detect the language from the text.
//
// This language code will be BCP 47.
//
// Returns empty string if no appropriate language was found.
std::string GetLanguage() const;
// Returns the value of a control such as an atomic text field (<input> or
// <textarea>), a content editable, a submit button, a slider, a progress bar,
// a scroll bar, a meter, a spinner, a <select> element, a date picker or an
// ARIA combo box. In order to minimize cross-process communication between
// the renderer and the browser, this method may compute the value from the
// control's inner text in the case of a content editable. For range controls,
// such as sliders and scroll bars, the value of aria-valuetext takes priority
// over the value of aria-valuenow.
std::string GetValueForControl() const;
//
// Helper functions for tables, table rows, and table cells.
// Most of these functions construct and cache an AXTableInfo behind
// the scenes to infer many properties of tables.
//
// These interfaces use attributes provided by the source of the
// AX tree where possible, but fills in missing details and ignores
// specified attributes when they're bad or inconsistent. That way
// you're guaranteed to get a valid, consistent table when using these
// interfaces.
//
// Table-like nodes (including grids). All indices are 0-based except
// ARIA indices are all 1-based. In other words, the top-left corner
// of the table is row 0, column 0, cell index 0 - but that same cell
// has a minimum ARIA row index of 1 and column index of 1.
//
// The below methods return std::nullopt if the AXNode they are called on is
// not inside a table.
bool IsTable() const;
std::optional<int> GetTableColCount() const;
std::optional<int> GetTableRowCount() const;
std::optional<int> GetTableAriaColCount() const;
std::optional<int> GetTableAriaRowCount() const;
std::optional<int> GetTableCellCount() const;
AXNode* GetTableCaption() const;
AXNode* GetTableCellFromIndex(int index) const;
AXNode* GetTableCellFromCoords(int row_index, int col_index) const;
AXNode* GetTableCellFromAriaCoords(int aria_row_index, int aria_col_index) const;
// Get all the column header node ids of the table.
std::vector<AXNodeID> GetTableColHeaderNodeIds() const;
// Get the column header node ids associated with |col_index|.
std::vector<AXNodeID> GetTableColHeaderNodeIds(int col_index) const;
// Get the row header node ids associated with |row_index|.
std::vector<AXNodeID> GetTableRowHeaderNodeIds(int row_index) const;
std::vector<AXNodeID> GetTableUniqueCellIds() const;
// Extra computed nodes for the accessibility tree for macOS:
// one column node for each table column, followed by one
// table header container node, or nullptr if not applicable.
const std::vector<raw_ptr<AXNode, VectorExperimental>>* GetExtraMacNodes()
const;
#if BUILDFLAG(IS_LINUX)
AXNode* GetExtraAnnouncementNode(
ax::mojom::AriaNotificationPriority priority_property) const;
#endif // BUILDFLAG(IS_LINUX)
// Return true for mock nodes added to the map, such as extra mac nodes.
bool IsGenerated() const;
// Table row-like nodes.
bool IsTableRow() const;
std::optional<int> GetTableRowRowIndex() const;
// Get the node ids that represent rows in a table.
std::vector<AXNodeID> GetTableRowNodeIds() const;
#if BUILDFLAG(IS_APPLE)
// Table column-like nodes. These nodes are only present on macOS.
bool IsTableColumn() const;
std::optional<int> GetTableColColIndex() const;
#endif // BUILDFLAG(IS_APPLE)
// Table cell-like nodes.
bool IsTableCellOrHeader() const;
std::optional<int> GetTableCellIndex() const;
std::optional<int> GetTableCellColIndex() const;
// The row index of a cell. If a row is passed in, use the first cell.
std::optional<int> GetTableCellRowIndex() const;
std::optional<int> GetTableCellColSpan() const;
std::optional<int> GetTableCellRowSpan() const;
std::optional<int> GetTableCellAriaColIndex() const;
// The ARIA row index of a cell. If a row is passed in, use the first cell.
std::optional<int> GetTableCellAriaRowIndex() const;
std::vector<AXNodeID> GetTableCellColHeaderNodeIds() const;
std::vector<AXNodeID> GetTableCellRowHeaderNodeIds() const;
void GetTableCellColHeaders(std::vector<AXNode*>* col_headers) const;
void GetTableCellRowHeaders(std::vector<AXNode*>* row_headers) const;
// Returns true if this node is a cell or a row/column header in an ARIA grid
// or treegrid.
bool IsCellOrHeaderOfAriaGrid() const;
// Return an object containing information about the languages detected on
// this node.
// Callers should not retain this pointer, instead they should request it
// every time it is needed.
//
// Returns nullptr if the node has no language info.
AXLanguageInfo* GetLanguageInfo() const;
// This should only be called by LabelLanguageForSubtree and is used as part
// of the language detection feature.
void SetLanguageInfo(std::unique_ptr<AXLanguageInfo> lang_info);
// Destroy the language info for this node.
void ClearLanguageInfo();
// Get a reference to the cached information stored for this node.
const AXComputedNodeData& GetComputedNodeData() const;
// Clear the cached information stored for this node because it is
// out-of-date.
void ClearComputedNodeData();
// Returns true if node is a group and is a direct descendant of a set-like
// element.
bool IsEmbeddedGroup() const;
// Returns true if this node has the ignored state or a presentational ARIA
// role. Focused nodes are, by design, not ignored.
bool IsIgnored() const;
// Some nodes are not ignored but should be skipped during text navigation.
// For example, on some platforms screen readers should not stop when
// encountering a splitter during character and word navigation.
bool IsIgnoredForTextNavigation() const;
// Returns true if node is invisible, or if it is ignored as determined by
// `AXNode::IsIgnored()`.
bool IsInvisibleOrIgnored() const;
// Returns true if an ancestor of this node (not including itself) is a
// leaf node, meaning that this node is not actually exposed to any
// platform's accessibility layer.
bool IsChildOfLeaf() const;
// Returns true if this is a leaf node that has no text content. Note that all
// descendants of a leaf node are not exposed to any platform's accessibility
// layer, but they may be used to compute the node's text content. Note also
// that, ignored nodes (leaf or otherwise) do not expose their text content or
// hypertext to the platforms' accessibility layer, but they expose the text
// content or hypertext of their unignored descendants.
//
// For example, empty text fields might have a set of unignored nested divs
// inside them:
// ++kTextField
// ++++kGenericContainer
// ++++++kGenericContainer
bool IsEmptyLeaf() const;
// Returns true if this is a leaf node, meaning all its
// descendants should not be exposed to any platform's accessibility
// layer.
//
// The definition of a leaf includes nodes with children that are exclusively
// an internal renderer implementation, such as the children of an HTML-based
// text field (<input> and <textarea>), as well as nodes with presentational
// children according to the ARIA and HTML5 Specs. Also returns true if all of
// the node's descendants are ignored.
//
// A leaf node should never have children that are focusable or
// that might send notifications.
bool IsLeaf() const;
// Helper to determine if the node is focusable. This does more than just
// use HasState(ax::mojom::State::kFocusable) -- it also checks whether the
// object is a likely activedescendant.
bool IsFocusable() const;
// Helper to determine whether the node can be an active descendant, and is a
// likely candidate to be one. An id and an ARIA role are required, and the
// role must be item-like.
bool IsLikelyARIAActiveDescendant() const;
// Returns true if this node is a list marker or if it's a descendant
// of a list marker node. Returns false otherwise.
bool IsInListMarker() const;
// Returns true if this node is a collapsed combobox select that is parent to
// a menu list popup.
bool IsCollapsedMenuListSelect() const;
// Returns true if this node is at the root of an accessibility tree that is
// hosted by a presentational iframe.
bool IsRootWebAreaForPresentationalIframe() const;
// Returns the popup button ancestor of this current node if any. The popup
// button needs to be the parent of a menu list popup and needs to be
// collapsed.
AXNode* GetCollapsedMenuListSelectAncestor() const;
// If this node is exposed to the platform's accessibility layer, returns this
// node. Otherwise, returns the lowest ancestor that is exposed to the
// platform. (See `IsLeaf()` and `IsIgnored()` for information on what is
// exposed to platform APIs.)
AXNode* GetLowestPlatformAncestor() const;
// If this node is within an editable region, returns the node that is at the
// root of that editable region, otherwise returns nullptr. In accessibility,
// an editable region is synonymous to a node with the kTextField role, or a
// contenteditable without the role, (see `AXNodeData::IsTextField()`).
AXNode* GetTextFieldAncestor() const;
// Get the native text field's deepest container; the lowest descendant that
// contains all its text. Returns nullptr if the text field is empty, or if it
// is not an atomic text field, (e.g., <input> or <textarea>).
AXNode* GetTextFieldInnerEditorElement() const;
// If this node is within a container (or widget) that supports either single
// or multiple selection, returns the node that represents the container.
AXNode* GetSelectionContainer() const;
// If this node is within a table, returns the node that represents the table.
AXNode* GetTableAncestor() const;
// Returns true if this node is either an atomic text field , or one of its
// ancestors is. An atomic text field does not expose its internal
// implementation to assistive software, appearing as a single leaf node in
// the accessibility tree. Examples include: An <input> or a <textarea> on the
// Web, a text field in a PDF form, a Views-based text field, or a native
// Android one.
bool IsDescendantOfAtomicTextField() const;
// Finds and returns a pointer to ordered set containing node.
AXNode* GetOrderedSet() const;
// Returns true if the node supports the read-only attribute.
bool IsReadOnlySupported() const;
// Returns true if the node is marked read-only or is disabled. By default,
// all nodes that can't be edited are read-only.
bool IsReadOnlyOrDisabled() const;
// Returns true if node is from Views (and not web content).
bool IsView() const;
private:
AXTableInfo* GetAncestorTableInfo() const;
void IdVectorToNodeVector(const std::vector<AXNodeID>& ids,
std::vector<AXNode*>* nodes) const;
int UpdateUnignoredCachedValuesRecursive(int start_index);
AXNode* ComputeLastUnignoredChildRecursive() const;
AXNode* ComputeFirstUnignoredChildRecursive() const;
// Returns the value of a range control such as a slider or a scroll bar in
// text format.
std::string GetTextForRangeValue() const;
// Returns the value of a color well (a color chooser control) in a human
// readable format. For example: "50% red 40% green 90% blue".
std::string GetValueForColorWell() const;
// Compute the actual value of a color attribute that needs to be
// blended with ancestor colors.
SkColor ComputeColorAttribute(ax::mojom::IntAttribute color_attr) const;
const raw_ptr<AXTree> tree_; // Owns this.
size_t index_in_parent_;
size_t unignored_index_in_parent_;
size_t unignored_child_count_ = 0;
const raw_ptr<AXNode> parent_;
std::vector<raw_ptr<AXNode, VectorExperimental>> children_;
// Stores information about this node that is immutable and which has been
// computed by the tree's source, such as `content::BlinkAXTreeSource`.
AXNodeData data_;
// See the class comment in "ax_hypertext.h" for an explanation of this
// member.
mutable AXHypertext hypertext_;
// Stores information about this node that can be computed on demand and
// cached.
mutable std::unique_ptr<AXComputedNodeData> computed_node_data_;
// Stores the detected language computed from the node's text.
std::unique_ptr<AXLanguageInfo> language_info_;
};
AX_EXPORT std::ostream& operator<<(std::ostream& stream, const AXNode& node);
AX_EXPORT std::ostream& operator<<(std::ostream& stream, const AXNode* node);
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>::ChildIteratorBase(const NodeType* parent,
NodeType* child)
: parent_(parent), child_(child) {}
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>::ChildIteratorBase(const ChildIteratorBase&
it)
: parent_(it.parent_), child_(it.child_) {}
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>&
AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>::operator++() {
// |child_ = nullptr| denotes the iterator's past-the-end condition. When we
// increment the iterator past the end, we remain at the past-the-end iterator
// condition.
if (child_ && parent_) {
if (child_ == (parent_->*LastChild)())
child_ = nullptr;
else
child_ = (child_->*NextSibling)();
}
return *this;
}
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>&
AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>::operator--() {
if (parent_) {
// If the iterator is past the end, |child_=nullptr|, decrement the iterator
// gives us the last iterator element.
if (!child_)
child_ = (parent_->*LastChild)();
// Decrement the iterator gives us the previous element, except when the
// iterator is at the beginning; in which case, decrementing the iterator
// remains at the beginning.
else if (child_ != (parent_->*FirstChild)())
child_ = (child_->*PreviousSibling)();
}
return *this;
}
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
NodeType* AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>::get() const {
DCHECK(child_);
return child_;
}
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
NodeType& AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>::operator*() const {
DCHECK(child_);
return *child_;
}
template <typename NodeType,
NodeType* (NodeType::*NextSibling)() const,
NodeType* (NodeType::*PreviousSibling)() const,
NodeType* (NodeType::*FirstChild)() const,
NodeType* (NodeType::*LastChild)() const>
NodeType* AXNode::ChildIteratorBase<NodeType,
NextSibling,
PreviousSibling,
FirstChild,
LastChild>::operator->() const {
DCHECK(child_);
return child_;
}
} // namespace ui
#endif // UI_ACCESSIBILITY_AX_NODE_H_