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chromium / chromium / src / 8d62647be580bec89db33ea771c23e609d4bc09d / . / ui / accessibility / ax_tree.cc
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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/accessibility/ax_tree.h"
#include <stddef.h>
#include <algorithm>
#include <numeric>
#include <utility>
#include "base/auto_reset.h"
#include "base/callback_helpers.h"
#include "base/check_op.h"
#include "base/command_line.h"
#include "base/containers/contains.h"
#include "base/debug/activity_tracker.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/histogram_macros.h"
#include "base/no_destructor.h"
#include "base/notreached.h"
#include "base/strings/stringprintf.h"
#include "ui/accessibility/accessibility_switches.h"
#include "ui/accessibility/ax_enums.mojom.h"
#include "ui/accessibility/ax_language_detection.h"
#include "ui/accessibility/ax_node.h"
#include "ui/accessibility/ax_node_position.h"
#include "ui/accessibility/ax_role_properties.h"
#include "ui/accessibility/ax_table_info.h"
#include "ui/accessibility/ax_tree_observer.h"
#include "ui/gfx/transform.h"
namespace ui {
namespace {
std::string TreeToStringHelper(const AXNode* node, int indent) {
if (!node)
return "";
return std::accumulate(
node->children().cbegin(), node->children().cend(),
std::string(2 * indent, ' ') + node->data().ToString() + "\n",
[indent](const std::string& str, const auto* child) {
return str + TreeToStringHelper(child, indent + 1);
});
}
template <typename K, typename V>
bool KeyValuePairsKeysMatch(std::vector<std::pair<K, V>> pairs1,
std::vector<std::pair<K, V>> pairs2) {
if (pairs1.size() != pairs2.size())
return false;
for (size_t i = 0; i < pairs1.size(); ++i) {
if (pairs1[i].first != pairs2[i].first)
return false;
}
return true;
}
template <typename K, typename V>
std::map<K, V> MapFromKeyValuePairs(std::vector<std::pair<K, V>> pairs) {
std::map<K, V> result;
for (size_t i = 0; i < pairs.size(); ++i)
result[pairs[i].first] = pairs[i].second;
return result;
}
// Given two vectors of <K, V> key, value pairs representing an "old" vs "new"
// state, or "before" vs "after", calls a callback function for each key that
// changed value. Note that if an attribute is removed, that will result in
// a call to the callback with the value changing from the previous value to
// |empty_value|, and similarly when an attribute is added.
template <typename K, typename V, typename F>
void CallIfAttributeValuesChanged(const std::vector<std::pair<K, V>>& pairs1,
const std::vector<std::pair<K, V>>& pairs2,
const V& empty_value,
F callback) {
// Fast path - if they both have the same keys in the same order.
if (KeyValuePairsKeysMatch(pairs1, pairs2)) {
for (size_t i = 0; i < pairs1.size(); ++i) {
if (pairs1[i].second != pairs2[i].second)
callback(pairs1[i].first, pairs1[i].second, pairs2[i].second);
}
return;
}
// Slower path - they don't have the same keys in the same order, so
// check all keys against each other, using maps to prevent this from
// becoming O(n^2) as the size grows.
auto map1 = MapFromKeyValuePairs(pairs1);
auto map2 = MapFromKeyValuePairs(pairs2);
for (size_t i = 0; i < pairs1.size(); ++i) {
const auto& new_iter = map2.find(pairs1[i].first);
if (pairs1[i].second != empty_value && new_iter == map2.end())
callback(pairs1[i].first, pairs1[i].second, empty_value);
}
for (size_t i = 0; i < pairs2.size(); ++i) {
const auto& iter = map1.find(pairs2[i].first);
if (iter == map1.end())
callback(pairs2[i].first, empty_value, pairs2[i].second);
else if (iter->second != pairs2[i].second)
callback(pairs2[i].first, iter->second, pairs2[i].second);
}
}
bool IsCollapsed(const AXNode* node) {
return node && node->data().HasState(ax::mojom::State::kCollapsed);
}
} // namespace
// This object is used to track structure changes that will occur for a specific
// AXID. This includes how many times we expect that a node with a specific AXID
// will be created and/or destroyed, and how many times a subtree rooted at AXID
// expects to be destroyed during an AXTreeUpdate.
//
// An AXTreeUpdate is a serialized representation of an atomic change to an
// AXTree. See also |AXTreeUpdate| which documents the nature and invariants
// required to atomically update the AXTree.
//
// The reason that we must track these counts, and the reason these are counts
// rather than a bool/flag is because an AXTreeUpdate may contain multiple
// AXNodeData updates for a given AXID. A common way that this occurs is when
// multiple AXTreeUpdates are merged together, combining their AXNodeData list.
// Additionally AXIDs may be reused after being removed from the tree,
// most notably when "reparenting" a node. A "reparent" occurs when an AXID is
// first destroyed from the tree then created again in the same AXTreeUpdate,
// which may also occur multiple times with merged updates.
//
// We need to accumulate these counts for 3 reasons :
// 1. To determine what structure changes *will* occur before applying
// updates to the tree so that we can notify observers of structure changes
// when the tree is still in a stable and unchanged state.
// 2. Capture any errors *before* applying updates to the tree structure
// due to the order of (or lack of) AXNodeData entries in the update
// so we can abort a bad update instead of applying it partway.
// 3. To validate that the expectations we accumulate actually match
// updates that are applied to the tree.
//
// To reiterate the invariants that this structure is taking a dependency on
// from |AXTreeUpdate|, suppose that the next AXNodeData to be applied is
// |node|. The following invariants must hold:
// 1. Either
// a) |node.id| is already in the tree, or
// b) the tree is empty, and
// |node| is the new root of the tree, and
// |node.role| == WebAXRoleRootWebArea.
// 2. Every child id in |node.child_ids| must either be already a child
// of this node, or a new id not previously in the tree. It is not
// allowed to "reparent" a child to this node without first removing
// that child from its previous parent.
// 3. When a new id appears in |node.child_ids|, the tree should create a
// new uninitialized placeholder node for it immediately. That
// placeholder must be updated within the same AXTreeUpdate, otherwise
// it's a fatal error. This guarantees the tree is always complete
// before or after an AXTreeUpdate.
struct PendingStructureChanges {
explicit PendingStructureChanges(const AXNode* node)
: destroy_subtree_count(0),
destroy_node_count(0),
create_node_count(0),
node_exists(!!node),
parent_node_id((node && node->parent())
? absl::optional<AXNodeID>{node->parent()->id()}
: absl::nullopt),
last_known_data(node ? &node->data() : nullptr) {}
// Returns true if this node has any changes remaining.
// This includes pending subtree or node destruction, and node creation.
bool DoesNodeExpectAnyStructureChanges() const {
return DoesNodeExpectSubtreeWillBeDestroyed() ||
DoesNodeExpectNodeWillBeDestroyed() ||
DoesNodeExpectNodeWillBeCreated();
}
// Returns true if there are any pending changes that require destroying
// this node or its subtree.
bool DoesNodeExpectSubtreeOrNodeWillBeDestroyed() const {
return DoesNodeExpectSubtreeWillBeDestroyed() ||
DoesNodeExpectNodeWillBeDestroyed();
}
// Returns true if the subtree rooted at this node needs to be destroyed
// during the update, but this may not be the next action that needs to be
// performed on the node.
bool DoesNodeExpectSubtreeWillBeDestroyed() const {
return destroy_subtree_count;
}
// Returns true if this node needs to be destroyed during the update, but this
// may not be the next action that needs to be performed on the node.
bool DoesNodeExpectNodeWillBeDestroyed() const { return destroy_node_count; }
// Returns true if this node needs be created during the update, but this
// may not be the next action that needs to be performed on the node.
bool DoesNodeExpectNodeWillBeCreated() const { return create_node_count; }
// Returns true if this node would exist in the tree as of the last pending
// update that was processed, and the node has not been provided node data.
bool DoesNodeRequireInit() const { return node_exists && !last_known_data; }
// Keep track of the number of times the subtree rooted at this node
// will be destroyed.
// An example of when this count may be larger than 1 is if updates were
// merged together. A subtree may be [created,] destroyed, created, and
// destroyed again within the same |AXTreeUpdate|. The important takeaway here
// is that an update may request destruction of a subtree rooted at an
// AXID more than once, not that a specific subtree is being destroyed
// more than once.
int32_t destroy_subtree_count;
// Keep track of the number of times this node will be destroyed.
// An example of when this count may be larger than 1 is if updates were
// merged together. A node may be [created,] destroyed, created, and destroyed
// again within the same |AXTreeUpdate|. The important takeaway here is that
// an AXID may request destruction more than once, not that a specific node
// is being destroyed more than once.
int32_t destroy_node_count;
// Keep track of the number of times this node will be created.
// An example of when this count may be larger than 1 is if updates were
// merged together. A node may be [destroyed,] created, destroyed, and created
// again within the same |AXTreeUpdate|. The important takeaway here is that
// an AXID may request creation more than once, not that a specific node is
// being created more than once.
int32_t create_node_count;
// Keep track of whether this node exists in the tree as of the last pending
// update that was processed.
bool node_exists;
// Keep track of the parent id for this node as of the last pending
// update that was processed.
absl::optional<AXNodeID> parent_node_id;
// Keep track of the last known node data for this node.
// This will be null either when a node does not exist in the tree, or
// when the node is new and has not been initialized with node data yet.
// This is needed to determine what children have changed between pending
// updates.
const AXNodeData* last_known_data;
};
// Represents the different states when computing PendingStructureChanges
// required for tree Unserialize.
enum class AXTreePendingStructureStatus {
// PendingStructureChanges have not begun computation.
kNotStarted,
// PendingStructureChanges are currently being computed.
kComputing,
// All PendingStructureChanges have successfully been computed.
kComplete,
// An error occurred when computing pending changes.
kFailed,
};
// Intermediate state to keep track of during a tree update.
struct AXTreeUpdateState {
AXTreeUpdateState(const AXTree& tree, const AXTreeUpdate& pending_tree_update)
: pending_update_status(AXTreePendingStructureStatus::kNotStarted),
root_will_be_created(false),
pending_tree_update(pending_tree_update),
tree(tree) {}
// Returns whether this update removes |node|.
bool IsRemovedNode(const AXNode* node) const {
return base::Contains(removed_node_ids, node->id());
}
// Returns whether this update creates a node marked by |node_id|.
bool IsCreatedNode(AXNodeID node_id) const {
return base::Contains(new_node_ids, node_id);
}
// Returns whether this update creates |node|.
bool IsCreatedNode(const AXNode* node) const {
return IsCreatedNode(node->id());
}
// Returns whether this update reparents |node|.
bool IsReparentedNode(const AXNode* node) const {
DCHECK_EQ(AXTreePendingStructureStatus::kComplete, pending_update_status)
<< "This method should not be called before pending changes have "
"finished computing.";
PendingStructureChanges* data = GetPendingStructureChanges(node->id());
if (!data)
return false;
// In order to know if the node will be reparented during the update,
// we check if either the node will be destroyed or has been destroyed at
// least once during the update.
// Since this method is only allowed to be called after calculating all
// pending structure changes, |node_exists| tells us if the node should
// exist after all updates have been applied.
return (data->DoesNodeExpectNodeWillBeDestroyed() || IsRemovedNode(node)) &&
data->node_exists;
}
// Returns true if the node should exist in the tree but doesn't have
// any node data yet.
bool DoesPendingNodeRequireInit(AXNodeID node_id) const {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
PendingStructureChanges* data = GetPendingStructureChanges(node_id);
return data && data->DoesNodeRequireInit();
}
// Returns the parent node id for the pending node.
absl::optional<AXNodeID> GetParentIdForPendingNode(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
PendingStructureChanges* data = GetOrCreatePendingStructureChanges(node_id);
DCHECK(!data->parent_node_id ||
ShouldPendingNodeExistInTree(*data->parent_node_id));
return data->parent_node_id;
}
// Returns true if this node should exist in the tree.
bool ShouldPendingNodeExistInTree(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
return GetOrCreatePendingStructureChanges(node_id)->node_exists;
}
// Returns the last known node data for a pending node.
const AXNodeData& GetLastKnownPendingNodeData(AXNodeID node_id) const {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
static base::NoDestructor<ui::AXNodeData> empty_data;
PendingStructureChanges* data = GetPendingStructureChanges(node_id);
return (data && data->last_known_data) ? *data->last_known_data
: *empty_data;
}
// Clear the last known pending data for |node_id|.
void ClearLastKnownPendingNodeData(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
GetOrCreatePendingStructureChanges(node_id)->last_known_data = nullptr;
}
// Update the last known pending node data for |node_data.id|.
void SetLastKnownPendingNodeData(const AXNodeData* node_data) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
GetOrCreatePendingStructureChanges(node_data->id)->last_known_data =
node_data;
}
// Returns the number of times the update is expected to destroy a
// subtree rooted at |node_id|.
int32_t GetPendingDestroySubtreeCount(AXNodeID node_id) const {
DCHECK_EQ(AXTreePendingStructureStatus::kComplete, pending_update_status)
<< "This method should not be called before pending changes have "
"finished computing.";
if (PendingStructureChanges* data = GetPendingStructureChanges(node_id))
return data->destroy_subtree_count;
return 0;
}
// Increments the number of times the update is expected to
// destroy a subtree rooted at |node_id|.
// Returns true on success, false on failure when the node will not exist.
bool IncrementPendingDestroySubtreeCount(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
PendingStructureChanges* data = GetOrCreatePendingStructureChanges(node_id);
if (!data->node_exists)
return false;
++data->destroy_subtree_count;
return true;
}
// Decrements the number of times the update is expected to
// destroy a subtree rooted at |node_id|.
void DecrementPendingDestroySubtreeCount(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComplete, pending_update_status)
<< "This method should not be called before pending changes have "
"finished computing.";
if (PendingStructureChanges* data = GetPendingStructureChanges(node_id)) {
DCHECK_GT(data->destroy_subtree_count, 0);
--data->destroy_subtree_count;
}
}
// Returns the number of times the update is expected to destroy
// a node with |node_id|.
int32_t GetPendingDestroyNodeCount(AXNodeID node_id) const {
DCHECK_EQ(AXTreePendingStructureStatus::kComplete, pending_update_status)
<< "This method should not be called before pending changes have "
"finished computing.";
if (PendingStructureChanges* data = GetPendingStructureChanges(node_id))
return data->destroy_node_count;
return 0;
}
// Increments the number of times the update is expected to
// destroy a node with |node_id|.
// Returns true on success, false on failure when the node will not exist.
bool IncrementPendingDestroyNodeCount(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
PendingStructureChanges* data = GetOrCreatePendingStructureChanges(node_id);
if (!data->node_exists)
return false;
++data->destroy_node_count;
data->node_exists = false;
data->last_known_data = nullptr;
data->parent_node_id = absl::nullopt;
if (pending_root_id == node_id)
pending_root_id = absl::nullopt;
return true;
}
// Decrements the number of times the update is expected to
// destroy a node with |node_id|.
void DecrementPendingDestroyNodeCount(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComplete, pending_update_status)
<< "This method should not be called before pending changes have "
"finished computing.";
if (PendingStructureChanges* data = GetPendingStructureChanges(node_id)) {
DCHECK_GT(data->destroy_node_count, 0);
--data->destroy_node_count;
}
}
// Returns the number of times the update is expected to create
// a node with |node_id|.
int32_t GetPendingCreateNodeCount(AXNodeID node_id) const {
DCHECK_EQ(AXTreePendingStructureStatus::kComplete, pending_update_status)
<< "This method should not be called before pending changes have "
"finished computing.";
if (PendingStructureChanges* data = GetPendingStructureChanges(node_id))
return data->create_node_count;
return 0;
}
// Increments the number of times the update is expected to
// create a node with |node_id|.
// Returns true on success, false on failure when the node will already exist.
bool IncrementPendingCreateNodeCount(
AXNodeID node_id,
absl::optional<AXNodeID> parent_node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
PendingStructureChanges* data = GetOrCreatePendingStructureChanges(node_id);
if (data->node_exists)
return false;
++data->create_node_count;
data->node_exists = true;
data->parent_node_id = parent_node_id;
return true;
}
// Decrements the number of times the update is expected to
// create a node with |node_id|.
void DecrementPendingCreateNodeCount(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComplete, pending_update_status)
<< "This method should not be called before pending changes have "
"finished computing.";
if (PendingStructureChanges* data = GetPendingStructureChanges(node_id)) {
DCHECK_GT(data->create_node_count, 0);
--data->create_node_count;
}
}
// Returns whether this update must invalidate the unignored cached
// values for |node_id|.
bool InvalidatesUnignoredCachedValues(AXNodeID node_id) {
return base::Contains(invalidate_unignored_cached_values_ids, node_id);
}
// Adds the parent of |node_id| to the list of nodes to invalidate unignored
// cached values.
void InvalidateParentNodeUnignoredCacheValues(AXNodeID node_id) {
DCHECK_EQ(AXTreePendingStructureStatus::kComputing, pending_update_status)
<< "This method should only be called while computing pending changes, "
"before updates are made to the tree.";
absl::optional<AXNodeID> parent_node_id =
GetParentIdForPendingNode(node_id);
if (parent_node_id) {
invalidate_unignored_cached_values_ids.insert(*parent_node_id);
}
}
// Indicates the status for calculating what changes will occur during
// an update before the update applies changes.
AXTreePendingStructureStatus pending_update_status;
// Keeps track of the root node id when calculating what changes will occur
// during an update before the update applies changes.
absl::optional<AXNodeID> pending_root_id;
// Keeps track of whether the root node will need to be created as a new node.
// This may occur either when the root node does not exist before applying
// updates to the tree (new tree), or if the root is the |node_id_to_clear|
// and will be destroyed before applying AXNodeData updates to the tree.
bool root_will_be_created;
// During an update, this keeps track of all nodes that have been
// implicitly referenced as part of this update, but haven't been
// updated yet. It's an error if there are any pending nodes at the
// end of Unserialize.
std::set<AXNodeID> pending_nodes;
// Keeps track of nodes whose cached unignored child count, or unignored
// index in parent may have changed, and must be updated.
std::set<AXNodeID> invalidate_unignored_cached_values_ids;
// Keeps track of nodes that have changed their node data.
std::set<AXNodeID> node_data_changed_ids;
// Keeps track of new nodes created during this update.
std::set<AXNodeID> new_node_ids;
// Keeps track of any nodes removed. Nodes are removed when their AXID no
// longer exist in the parent |child_ids| list, or the node is part of to the
// subtree of the AXID that was explicitally cleared with |node_id_to_clear|.
// Used to identify re-parented nodes. A re-parented occurs when any AXID
// is first removed from the tree then added to the tree again.
std::set<AXNodeID> removed_node_ids;
// Maps between a node id and its pending update information.
std::map<AXNodeID, std::unique_ptr<PendingStructureChanges>>
node_id_to_pending_data;
// Maps between a node id and the data it owned before being updated.
// We need to keep this around in order to correctly fire post-update events.
std::map<AXNodeID, AXNodeData> old_node_id_to_data;
// Optional copy of the old tree data, only populated when the tree
// data has changed.
absl::optional<AXTreeData> old_tree_data;
// Keep track of the pending tree update to help create useful error messages.
// TODO(crbug.com/1156601) Revert this once we have the crash data we need
// (crrev.com/c/2892259).
const AXTreeUpdate& pending_tree_update;
private:
PendingStructureChanges* GetPendingStructureChanges(AXNodeID node_id) const {
auto iter = node_id_to_pending_data.find(node_id);
return (iter != node_id_to_pending_data.cend()) ? iter->second.get()
: nullptr;
}
PendingStructureChanges* GetOrCreatePendingStructureChanges(
AXNodeID node_id) {
auto iter = node_id_to_pending_data.find(node_id);
if (iter == node_id_to_pending_data.cend()) {
const AXNode* node = tree.GetFromId(node_id);
iter = node_id_to_pending_data
.emplace(std::make_pair(
node_id, std::make_unique<PendingStructureChanges>(node)))
.first;
}
return iter->second.get();
}
// We need to hold onto a reference to the AXTree so that we can
// lazily initialize |PendingStructureChanges| objects.
const AXTree& tree;
};
AXTree::NodeSetSizePosInSetInfo::NodeSetSizePosInSetInfo() = default;
AXTree::NodeSetSizePosInSetInfo::~NodeSetSizePosInSetInfo() = default;
struct AXTree::OrderedSetContent {
explicit OrderedSetContent(const AXNode* ordered_set = nullptr)
: ordered_set_(ordered_set) {}
~OrderedSetContent() = default;
std::vector<const AXNode*> set_items_;
// Some ordered set items may not be associated with an ordered set.
const AXNode* ordered_set_;
};
struct AXTree::OrderedSetItemsMap {
OrderedSetItemsMap() = default;
~OrderedSetItemsMap() = default;
// Check if a particular hierarchical level exists in this map.
bool HierarchicalLevelExists(absl::optional<int> level) {
if (items_map_.find(level) == items_map_.end())
return false;
return true;
}
// Add the OrderedSetContent to the corresponding hierarchical level in the
// map.
void Add(absl::optional<int> level,
const OrderedSetContent& ordered_set_content) {
if (!HierarchicalLevelExists(level))
items_map_[level] = std::vector<OrderedSetContent>();
items_map_[level].push_back(ordered_set_content);
}
// Add an ordered set item to the OrderedSetItemsMap given its hierarchical
// level. We always want to append the item to the last OrderedSetContent of
// that hierarchical level, due to the following:
// - The last OrderedSetContent on any level of the items map is in progress
// of being populated.
// - All other OrderedSetContent other than the last one on a level
// represents a complete ordered set and should not be modified.
void AddItemToBack(absl::optional<int> level, const AXNode* item) {
if (!HierarchicalLevelExists(level))
return;
std::vector<OrderedSetContent>& sets_list = items_map_[level];
if (!sets_list.empty()) {
OrderedSetContent& ordered_set_content = sets_list.back();
ordered_set_content.set_items_.push_back(item);
}
}
// Retrieve the first OrderedSetContent of the OrderedSetItemsMap.
OrderedSetContent* GetFirstOrderedSetContent() {
if (items_map_.empty())
return nullptr;
std::vector<OrderedSetContent>& sets_list = items_map_.begin()->second;
if (sets_list.empty())
return nullptr;
return &(sets_list.front());
}
// Clears all the content in the map.
void Clear() { items_map_.clear(); }
// Maps a hierarchical level to a list of OrderedSetContent.
std::map<absl::optional<int32_t>, std::vector<OrderedSetContent>> items_map_;
};
AXTree::AXTree() {
AXNodeData root;
root.id = kInvalidAXNodeID;
AXTreeUpdate initial_state;
initial_state.root_id = kInvalidAXNodeID;
initial_state.nodes.push_back(root);
CHECK(Unserialize(initial_state)) << error();
// TODO(chrishall): should language_detection_manager be a member or pointer?
// TODO(chrishall): do we want to initialize all the time, on demand, or only
// when feature flag is set?
DCHECK(!language_detection_manager);
language_detection_manager =
std::make_unique<AXLanguageDetectionManager>(this);
}
AXTree::AXTree(const AXTreeUpdate& initial_state) {
CHECK(Unserialize(initial_state)) << error();
DCHECK(!language_detection_manager);
language_detection_manager =
std::make_unique<AXLanguageDetectionManager>(this);
}
AXTree::~AXTree() {
Destroy();
}
void AXTree::AddObserver(AXTreeObserver* observer) {
observers_.AddObserver(observer);
}
bool AXTree::HasObserver(AXTreeObserver* observer) {
return observers_.HasObserver(observer);
}
void AXTree::RemoveObserver(AXTreeObserver* observer) {
observers_.RemoveObserver(observer);
}
AXTreeID AXTree::GetAXTreeID() const {
return data().tree_id;
}
const AXTreeData& AXTree::data() const {
return data_;
}
AXNode* AXTree::GetFromId(AXNodeID id) const {
auto iter = id_map_.find(id);
return iter != id_map_.end() ? iter->second : nullptr;
}
void AXTree::Destroy() {
table_info_map_.clear();
if (root_) {
RecursivelyNotifyNodeDeletedForTreeTeardown(root_);
base::AutoReset<bool> update_state_resetter(&tree_update_in_progress_,
true);
DestroyNodeAndSubtree(root_, nullptr);
root_ = nullptr;
}
}
void AXTree::UpdateData(const AXTreeData& new_data) {
if (data_ == new_data)
return;
AXTreeData old_data = data_;
data_ = new_data;
for (AXTreeObserver& observer : observers_)
observer.OnTreeDataChanged(this, old_data, new_data);
}
gfx::RectF AXTree::RelativeToTreeBoundsInternal(const AXNode* node,
gfx::RectF bounds,
bool* offscreen,
bool clip_bounds,
bool allow_recursion) const {
// If |bounds| is uninitialized, which is not the same as empty,
// start with the node bounds.
if (bounds.width() == 0 && bounds.height() == 0) {
bounds = node->data().relative_bounds.bounds;
// If the node bounds is empty (either width or height is zero),
// try to compute good bounds from the children.
// If a tree update is in progress, skip this step as children may be in a
// bad state.
if (bounds.IsEmpty() && !GetTreeUpdateInProgressState() &&
allow_recursion) {
for (size_t i = 0; i < node->children().size(); i++) {
ui::AXNode* child = node->children()[i];
bool ignore_offscreen;
gfx::RectF child_bounds = RelativeToTreeBoundsInternal(
child, gfx::RectF(), &ignore_offscreen, clip_bounds,
/* allow_recursion = */ false);
bounds.Union(child_bounds);
}
if (bounds.width() > 0 && bounds.height() > 0) {
return bounds;
}
}
} else {
bounds.Offset(node->data().relative_bounds.bounds.x(),
node->data().relative_bounds.bounds.y());
}
const AXNode* original_node = node;
while (node != nullptr) {
if (node->data().relative_bounds.transform)
node->data().relative_bounds.transform->TransformRect(&bounds);
// Apply any transforms and offsets for each node and then walk up to
// its offset container. If no offset container is specified, coordinates
// are relative to the root node.
const AXNode* container =
GetFromId(node->data().relative_bounds.offset_container_id);
if (!container && container != root())
container = root();
if (!container || container == node)
break;
gfx::RectF container_bounds = container->data().relative_bounds.bounds;
bounds.Offset(container_bounds.x(), container_bounds.y());
int scroll_x = 0;
int scroll_y = 0;
if (container->data().GetIntAttribute(ax::mojom::IntAttribute::kScrollX,
&scroll_x) &&
container->data().GetIntAttribute(ax::mojom::IntAttribute::kScrollY,
&scroll_y)) {
bounds.Offset(-scroll_x, -scroll_y);
}
// Get the intersection between the bounds and the container.
gfx::RectF intersection = bounds;
intersection.Intersect(container_bounds);
// Calculate the clipped bounds to determine offscreen state.
gfx::RectF clipped = bounds;
// If this node has the kClipsChildren attribute set, clip the rect to fit.
if (container->data().GetBoolAttribute(
ax::mojom::BoolAttribute::kClipsChildren)) {
if (!intersection.IsEmpty()) {
// We can simply clip it to the container.
clipped = intersection;
} else {
// Totally offscreen. Find the nearest edge or corner.
// Make the minimum dimension 1 instead of 0.
if (clipped.x() >= container_bounds.width()) {
clipped.set_x(container_bounds.right() - 1);
clipped.set_width(1);
} else if (clipped.x() + clipped.width() <= 0) {
clipped.set_x(container_bounds.x());
clipped.set_width(1);
}
if (clipped.y() >= container_bounds.height()) {
clipped.set_y(container_bounds.bottom() - 1);
clipped.set_height(1);
} else if (clipped.y() + clipped.height() <= 0) {
clipped.set_y(container_bounds.y());
clipped.set_height(1);
}
}
}
if (clip_bounds)
bounds = clipped;
if (container->data().GetBoolAttribute(
ax::mojom::BoolAttribute::kClipsChildren) &&
intersection.IsEmpty() && !clipped.IsEmpty()) {
// If it is offscreen with respect to its parent, and the node itself is
// not empty, label it offscreen.
// Here we are extending the definition of offscreen to include elements
// that are clipped by their parents in addition to those clipped by
// the rootWebArea.
// No need to update |offscreen| if |intersection| is not empty, because
// it should be false by default.
if (offscreen != nullptr)
*offscreen |= true;
}
node = container;
}
// If we don't have any size yet, try to adjust the bounds to fill the
// nearest ancestor that does have bounds.
//
// The rationale is that it's not useful to the user for an object to
// have no width or height and it's probably a bug; it's better to
// reflect the bounds of the nearest ancestor rather than a 0x0 box.
// Tag this node as 'offscreen' because it has no true size, just a
// size inherited from the ancestor.
if (bounds.width() == 0 && bounds.height() == 0) {
const AXNode* ancestor = original_node->parent();
gfx::RectF ancestor_bounds;
while (ancestor) {
ancestor_bounds = ancestor->data().relative_bounds.bounds;
if (ancestor_bounds.width() > 0 || ancestor_bounds.height() > 0)
break;
ancestor = ancestor->parent();
}
if (ancestor && allow_recursion) {
bool ignore_offscreen;
bool allow_recursion = false;
ancestor_bounds = RelativeToTreeBoundsInternal(
ancestor, gfx::RectF(), &ignore_offscreen, clip_bounds,
allow_recursion);
gfx::RectF original_bounds = original_node->data().relative_bounds.bounds;
if (original_bounds.x() == 0 && original_bounds.y() == 0) {
bounds = ancestor_bounds;
} else {
bounds.set_width(std::max(0.0f, ancestor_bounds.right() - bounds.x()));
bounds.set_height(
std::max(0.0f, ancestor_bounds.bottom() - bounds.y()));
}
if (offscreen != nullptr)
*offscreen |= true;
}
}
return bounds;
}
gfx::RectF AXTree::RelativeToTreeBounds(const AXNode* node,
gfx::RectF bounds,
bool* offscreen,
bool clip_bounds) const {
bool allow_recursion = true;
return RelativeToTreeBoundsInternal(node, bounds, offscreen, clip_bounds,
allow_recursion);
}
gfx::RectF AXTree::GetTreeBounds(const AXNode* node,
bool* offscreen,
bool clip_bounds) const {
return RelativeToTreeBounds(node, gfx::RectF(), offscreen, clip_bounds);
}
std::set<AXNodeID> AXTree::GetReverseRelations(ax::mojom::IntAttribute attr,
AXNodeID dst_id) const {
DCHECK(IsNodeIdIntAttribute(attr));
// Conceptually, this is the "const" version of:
// return int_reverse_relations_[attr][dst_id];
const auto& attr_relations = int_reverse_relations_.find(attr);
if (attr_relations != int_reverse_relations_.end()) {
const auto& result = attr_relations->second.find(dst_id);
if (result != attr_relations->second.end())
return result->second;
}
return std::set<AXNodeID>();
}
std::set<AXNodeID> AXTree::GetReverseRelations(ax::mojom::IntListAttribute attr,
AXNodeID dst_id) const {
DCHECK(IsNodeIdIntListAttribute(attr));
// Conceptually, this is the "const" version of:
// return intlist_reverse_relations_[attr][dst_id];
const auto& attr_relations = intlist_reverse_relations_.find(attr);
if (attr_relations != intlist_reverse_relations_.end()) {
const auto& result = attr_relations->second.find(dst_id);
if (result != attr_relations->second.end())
return result->second;
}
return std::set<AXNodeID>();
}
std::set<AXNodeID> AXTree::GetNodeIdsForChildTreeId(
AXTreeID child_tree_id) const {
// Conceptually, this is the "const" version of:
// return child_tree_id_reverse_map_[child_tree_id];
const auto& result = child_tree_id_reverse_map_.find(child_tree_id);
if (result != child_tree_id_reverse_map_.end())
return result->second;
return std::set<AXNodeID>();
}
const std::set<AXTreeID> AXTree::GetAllChildTreeIds() const {
std::set<AXTreeID> result;
for (auto entry : child_tree_id_reverse_map_)
result.insert(entry.first);
return result;
}
bool AXTree::Unserialize(const AXTreeUpdate& update) {
event_intents_ = update.event_intents;
base::ScopedClosureRunner clear_event_intents(base::BindOnce(
[](std::vector<AXEventIntent>* event_intents) { event_intents->clear(); },
&event_intents_));
AXTreeUpdateState update_state(*this, update);
const AXNodeID old_root_id = root_ ? root_->id() : kInvalidAXNodeID;
// Accumulates the work that will be required to update the AXTree.
// This allows us to notify observers of structure changes when the
// tree is still in a stable and unchanged state.
if (!ComputePendingChanges(update, &update_state))
return false;
// Log unserialize perf after early returns.
SCOPED_UMA_HISTOGRAM_TIMER("Accessibility.Performance.Tree.Unserialize");
// Notify observers of subtrees and nodes that are about to be destroyed or
// reparented, this must be done before applying any updates to the tree.
for (auto&& pair : update_state.node_id_to_pending_data) {
const AXNodeID node_id = pair.first;
const std::unique_ptr<PendingStructureChanges>& data = pair.second;
if (data->DoesNodeExpectSubtreeOrNodeWillBeDestroyed()) {
if (AXNode* node = GetFromId(node_id)) {
if (data->DoesNodeExpectSubtreeWillBeDestroyed())
NotifySubtreeWillBeReparentedOrDeleted(node, &update_state);
if (data->DoesNodeExpectNodeWillBeDestroyed())
NotifyNodeWillBeReparentedOrDeleted(node, &update_state);
}
}
}
// Notify observers of nodes that are about to change their data.
// This must be done before applying any updates to the tree.
// This is iterating in reverse order so that we only notify once per node id,
// and that we only notify the initial node data against the final node data,
// unless the node is a new root.
std::set<AXNodeID> notified_node_data_will_change;
for (size_t i = update.nodes.size(); i-- > 0;) {
const AXNodeData& new_data = update.nodes[i];
const bool is_new_root =
update_state.root_will_be_created && new_data.id == update.root_id;
if (!is_new_root) {
AXNode* node = GetFromId(new_data.id);
if (node && notified_node_data_will_change.insert(new_data.id).second)
NotifyNodeDataWillChange(node->data(), new_data);
}
}
// Now that we have finished sending events for changes that will happen,
// set update state to true. |tree_update_in_progress_| gets set back to
// false whenever this function exits.
base::AutoReset<bool> update_state_resetter(&tree_update_in_progress_, true);
// Handle |node_id_to_clear| before applying ordinary node updates.
// We distinguish between updating the root, e.g. changing its children or
// some of its attributes, or replacing the root completely. If the root is
// being updated, update.node_id_to_clear should hold the current root's ID.
// Otherwise if the root is being replaced, update.root_id should hold the ID
// of the new root.
bool root_updated = false;
if (update.node_id_to_clear != kInvalidAXNodeID) {
// If the incoming tree was initialized with a root with an id != 1, the
// update won't match the tree created by CreateEmptyDocument In this
// case, the update won't be able to set the right node_id_to_clear.
// If node_id_to_clear was set and the update's root_id doesn't match the
// old_root_id, we assume that the update meant to replace the root.
int node_id_to_clear = update.node_id_to_clear;
if (!GetFromId(node_id_to_clear) && update.root_id == node_id_to_clear &&
update.root_id != old_root_id && root_)
node_id_to_clear = old_root_id;
if (AXNode* cleared_node = GetFromId(node_id_to_clear)) {
DCHECK(root_);
if (cleared_node == root_) {
// Only destroy the root if the root was replaced and not if it's simply
// updated. To figure out if the root was simply updated, we compare
// the ID of the new root with the existing root ID.
if (update.root_id != old_root_id) {
// Clear root_ before calling DestroySubtree so that root_ doesn't
// ever point to an invalid node.
AXNode* old_root = root_;
root_ = nullptr;
DestroySubtree(old_root, &update_state);
} else {
// If the root has simply been updated, we treat it like an update to
// any other node.
root_updated = true;
}
}
// If the tree doesn't exists any more because the root has just been
// replaced, there is nothing more to clear.
if (root_) {
for (auto* child : cleared_node->children())
DestroySubtree(child, &update_state);
std::vector<AXNode*> children;
cleared_node->SwapChildren(&children);
update_state.pending_nodes.insert(cleared_node->id());
}
}
}
DCHECK_EQ(!GetFromId(update.root_id), update_state.root_will_be_created);
// Update the tree data, do not call |UpdateData| since we want to defer
// the |OnTreeDataChanged| event until after the tree has finished updating.
if (update.has_tree_data && data_ != update.tree_data) {
update_state.old_tree_data = data_;
data_ = update.tree_data;
}
// Update all of the nodes in the update.
for (size_t i = 0; i < update.nodes.size(); ++i) {
const bool is_new_root = update_state.root_will_be_created &&
update.nodes[i].id == update.root_id;
if (!UpdateNode(update.nodes[i], is_new_root, &update_state))
return false;
}
if (!root_) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kNoRoot);
RecordError("Tree has no root.");
return false;
}
if (!ValidatePendingChangesComplete(update_state))
return false;
std::vector<AXTreeObserver::Change> changes;
changes.reserve(update.nodes.size());
// Look for changes to nodes that are a descendant of a table,
// and invalidate their table info if so. We have to walk up the
// ancestry of every node that was updated potentially, so keep track of
// ids that were checked to eliminate duplicate work.
std::set<AXNodeID> table_ids_checked;
for (const AXNodeData& node_data : update.nodes) {
AXNode* node = GetFromId(node_data.id);
while (node) {
if (table_ids_checked.find(node->id()) != table_ids_checked.end())
break;
// Remove any table infos.
const auto& table_info_entry = table_info_map_.find(node->id());
if (table_info_entry != table_info_map_.end()) {
table_info_entry->second->Invalidate();
#if defined(AX_EXTRA_MAC_NODES)
// It will emit children changed notification on mac to make sure that
// extra mac accessibles are recreated.
changes.emplace_back(node, AXTreeObserver::NODE_CHANGED);
#endif
}
table_ids_checked.insert(node->id());
node = node->parent();
}
}
// Clears |node_set_size_pos_in_set_info_map_|
node_set_size_pos_in_set_info_map_.clear();
std::set<AXNodeID> visited_observer_changes;
for (size_t i = 0; i < update.nodes.size(); ++i) {
AXNode* node = GetFromId(update.nodes[i].id);
if (!node || !visited_observer_changes.emplace(update.nodes[i].id).second)
continue;
bool is_new_node = update_state.IsCreatedNode(node);
bool is_reparented_node = update_state.IsReparentedNode(node);
AXTreeObserver::ChangeType change = AXTreeObserver::NODE_CHANGED;
if (is_new_node) {
if (is_reparented_node) {
// A reparented subtree is any new node whose parent either doesn't
// exist, or whose parent is not new.
// Note that we also need to check for the special case when we update
// the root without replacing it.
bool is_subtree = !node->parent() ||
!update_state.IsCreatedNode(node->parent()) ||
(node->parent() == root_ && root_updated);
change = is_subtree ? AXTreeObserver::SUBTREE_REPARENTED
: AXTreeObserver::NODE_REPARENTED;
} else {
// A new subtree is any new node whose parent is either not new, or
// whose parent happens to be new only because it has been reparented.
// Note that we also need to check for the special case when we update
// the root without replacing it.
bool is_subtree = !node->parent() ||
!update_state.IsCreatedNode(node->parent()) ||
update_state.IsRemovedNode(node->parent()) ||
(node->parent() == root_ && root_updated);
change = is_subtree ? AXTreeObserver::SUBTREE_CREATED
: AXTreeObserver::NODE_CREATED;
}
}
changes.push_back(AXTreeObserver::Change(node, change));
}
// Update the unignored cached values as necessary, ensuring that we only
// update once for each unignored node.
// If the node is ignored, we must update from an unignored ancestor.
std::set<AXNodeID> updated_unignored_cached_values_ids;
for (AXNodeID node_id : update_state.invalidate_unignored_cached_values_ids) {
AXNode* node = GetFromId(node_id);
while (node && node->data().IsIgnored())
node = node->parent();
if (node && updated_unignored_cached_values_ids.insert(node->id()).second)
node->UpdateUnignoredCachedValues();
}
// Tree is no longer updating.
SetTreeUpdateInProgressState(false);
// Now that the tree is stable and its nodes have been updated, notify if
// the tree data changed. We must do this after updating nodes in case the
// root has been replaced, so observers have the most up-to-date information.
if (update_state.old_tree_data) {
for (AXTreeObserver& observer : observers_)
observer.OnTreeDataChanged(this, *update_state.old_tree_data, data_);
}
// Now that the unignored cached values are up to date, update observers to
// the nodes that were deleted from the tree but not reparented.
for (AXNodeID node_id : update_state.removed_node_ids) {
if (!update_state.IsCreatedNode(node_id))
NotifyNodeHasBeenDeleted(node_id);
}
// Now that the unignored cached values are up to date, update observers to
// new nodes in the tree.
for (AXNodeID node_id : update_state.new_node_ids)
NotifyNodeHasBeenReparentedOrCreated(GetFromId(node_id), &update_state);
// Now that the unignored cached values are up to date, update observers to
// node changes.
for (AXNodeID node_data_changed_id : update_state.node_data_changed_ids) {
AXNode* node = GetFromId(node_data_changed_id);
DCHECK(node);
// If the node exists and is in the old data map, then the node data
// may have changed unless this is a new root.
const bool is_new_root = update_state.root_will_be_created &&
node_data_changed_id == update.root_id;
if (!is_new_root) {
auto it = update_state.old_node_id_to_data.find(node_data_changed_id);
if (it != update_state.old_node_id_to_data.end()) {
const AXNodeData& old_node_data = it->second;
NotifyNodeDataHasBeenChanged(node, old_node_data, node->data());
}
}
// |OnNodeChanged| should be fired for all nodes that have been updated.
for (AXTreeObserver& observer : observers_)
observer.OnNodeChanged(this, node);
}
for (AXTreeObserver& observer : observers_)
observer.OnAtomicUpdateFinished(this, root_->id() != old_root_id, changes);
return true;
}
AXTableInfo* AXTree::GetTableInfo(const AXNode* const_table_node) const {
DCHECK(!GetTreeUpdateInProgressState());
// Note: the const_casts are here because we want this function to be able
// to be called from a const virtual function on AXNode. AXTableInfo is
// computed on demand and cached, but that's an implementation detail
// we want to hide from users of this API.
AXNode* table_node = const_cast<AXNode*>(const_table_node);
AXTree* tree = const_cast<AXTree*>(this);
DCHECK(table_node);
const auto& cached = table_info_map_.find(table_node->id());
if (cached != table_info_map_.end()) {
// Get existing table info, and update if invalid because the
// tree has changed since the last time we accessed it.
AXTableInfo* table_info = cached->second.get();
if (!table_info->valid()) {
if (!table_info->Update()) {
// If Update() returned false, this is no longer a valid table.
// Remove it from the map.
table_info_map_.erase(table_node->id());
return nullptr;
}
}
return table_info;
}
AXTableInfo* table_info = AXTableInfo::Create(tree, table_node);
if (!table_info)
return nullptr;
table_info_map_[table_node->id()] = base::WrapUnique<AXTableInfo>(table_info);
return table_info;
}
std::string AXTree::ToString() const {
return "AXTree" + data_.ToString() + "\n" + TreeToStringHelper(root_, 0);
}
AXNode* AXTree::CreateNode(AXNode* parent,
AXNodeID id,
size_t index_in_parent,
AXTreeUpdateState* update_state) {
DCHECK(GetTreeUpdateInProgressState());
// |update_state| must already contain information about all of the expected
// changes and invalidations to apply. If any of these are missing, observers
// may not be notified of changes.
DCHECK(!GetFromId(id));
DCHECK_GT(update_state->GetPendingCreateNodeCount(id), 0);
DCHECK(update_state->InvalidatesUnignoredCachedValues(id));
DCHECK(!parent ||
update_state->InvalidatesUnignoredCachedValues(parent->id()));
update_state->DecrementPendingCreateNodeCount(id);
update_state->new_node_ids.insert(id);
// If this node is the root, use the given index_in_parent as the unignored
// index in parent to provide consistency with index_in_parent.
AXNode* new_node = new AXNode(this, parent, id, index_in_parent,
parent ? 0 : index_in_parent);
id_map_[new_node->id()] = new_node;
return new_node;
}
bool AXTree::ComputePendingChanges(const AXTreeUpdate& update,
AXTreeUpdateState* update_state) {
DCHECK_EQ(AXTreePendingStructureStatus::kNotStarted,
update_state->pending_update_status)
<< "Pending changes have already started being computed.";
update_state->pending_update_status =
AXTreePendingStructureStatus::kComputing;
base::AutoReset<absl::optional<AXNodeID>> pending_root_id_resetter(
&update_state->pending_root_id,
root_ ? absl::optional<AXNodeID>{root_->id()} : absl::nullopt);
// We distinguish between updating the root, e.g. changing its children or
// some of its attributes, or replacing the root completely. If the root is
// being updated, update.node_id_to_clear should hold the current root's ID.
// Otherwise if the root is being replaced, update.root_id should hold the ID
// of the new root.
if (update.node_id_to_clear != kInvalidAXNodeID) {
if (AXNode* cleared_node = GetFromId(update.node_id_to_clear)) {
DCHECK(root_);
if (cleared_node == root_ &&
update.root_id != update_state->pending_root_id) {
// Only destroy the root if the root was replaced and not if it's simply
// updated. To figure out if the root was simply updated, we compare
// the ID of the new root with the existing root ID.
MarkSubtreeForDestruction(*update_state->pending_root_id, update_state);
}
// If the tree has been marked for destruction because the root will be
// replaced, there is nothing more to clear.
if (update_state->ShouldPendingNodeExistInTree(root_->id())) {
update_state->invalidate_unignored_cached_values_ids.insert(
cleared_node->id());
update_state->ClearLastKnownPendingNodeData(cleared_node->id());
for (AXNode* child : cleared_node->children()) {
MarkSubtreeForDestruction(child->id(), update_state);
}
}
}
}
update_state->root_will_be_created =
!GetFromId(update.root_id) ||
!update_state->ShouldPendingNodeExistInTree(update.root_id);
// Populate |update_state| with all of the changes that will be performed
// on the tree during the update.
for (const AXNodeData& new_data : update.nodes) {
bool is_new_root =
update_state->root_will_be_created && new_data.id == update.root_id;
if (!ComputePendingChangesToNode(new_data, is_new_root, update_state)) {
update_state->pending_update_status =
AXTreePendingStructureStatus::kFailed;
return false;
}
}
update_state->pending_update_status = AXTreePendingStructureStatus::kComplete;
return true;
}
bool AXTree::ComputePendingChangesToNode(const AXNodeData& new_data,
bool is_new_root,
AXTreeUpdateState* update_state) {
// Compare every child's index in parent in the update with the existing
// index in parent. If the order has changed, invalidate the cached
// unignored index in parent.
for (size_t j = 0; j < new_data.child_ids.size(); j++) {
AXNode* node = GetFromId(new_data.child_ids[j]);
if (node && node->GetIndexInParent() != j)
update_state->InvalidateParentNodeUnignoredCacheValues(node->id());
}
// If the node does not exist in the tree throw an error unless this
// is the new root and it can be created.
if (!update_state->ShouldPendingNodeExistInTree(new_data.id)) {
if (!is_new_root) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kNotInTree);
RecordError(base::StringPrintf(
"%d will not be in the tree and is not the new root", new_data.id));
return false;
}
// Creation is implicit for new root nodes. If |new_data.id| is already
// pending for creation, then it must be a duplicate entry in the tree.
if (!update_state->IncrementPendingCreateNodeCount(new_data.id,
absl::nullopt)) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kCreationPending);
RecordError(base::StringPrintf(
"Node %d is already pending for creation, cannot be the new root",
new_data.id));
return false;
}
if (update_state->pending_root_id) {
MarkSubtreeForDestruction(*update_state->pending_root_id, update_state);
}
update_state->pending_root_id = new_data.id;
}
// Create a set of new child ids so we can use it to find the nodes that
// have been added and removed. Returns false if a duplicate is found.
std::set<AXNodeID> new_child_id_set;
for (AXNodeID new_child_id : new_data.child_ids) {
if (base::Contains(new_child_id_set, new_child_id)) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kDuplicateChild);
RecordError(base::StringPrintf("Node %d has duplicate child id %d",
new_data.id, new_child_id));
return false;
}
new_child_id_set.insert(new_child_id);
}
// If the node has not been initialized yet then its node data has either been
// cleared when handling |node_id_to_clear|, or it's a new node.
// In either case, all children must be created.
if (update_state->DoesPendingNodeRequireInit(new_data.id)) {
update_state->invalidate_unignored_cached_values_ids.insert(new_data.id);
// If this node has been cleared via |node_id_to_clear| or is a new node,
// the last-known parent's unignored cache needs to be updated.
update_state->InvalidateParentNodeUnignoredCacheValues(new_data.id);
for (AXNodeID child_id : new_child_id_set) {
// If a |child_id| is already pending for creation, then it must be a
// duplicate entry in the tree.
update_state->invalidate_unignored_cached_values_ids.insert(child_id);
if (!update_state->IncrementPendingCreateNodeCount(child_id,
new_data.id)) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kCreationPendingForChild);
RecordError(base::StringPrintf(
"Node %d is already pending for creation, cannot be a new child",
child_id));
return false;
}
}
update_state->SetLastKnownPendingNodeData(&new_data);
return true;
}
const AXNodeData& old_data =
update_state->GetLastKnownPendingNodeData(new_data.id);
// Create a set of old child ids so we can use it to find the nodes that
// have been added and removed.
std::set<AXNodeID> old_child_id_set(old_data.child_ids.cbegin(),
old_data.child_ids.cend());
std::vector<AXNodeID> create_or_destroy_ids;
std::set_symmetric_difference(
old_child_id_set.cbegin(), old_child_id_set.cend(),
new_child_id_set.cbegin(), new_child_id_set.cend(),
std::back_inserter(create_or_destroy_ids));
// If the node has changed ignored state or there are any differences in
// its children, then its unignored cached values must be invalidated.
const bool ignored_changed = old_data.IsIgnored() != new_data.IsIgnored();
if (!create_or_destroy_ids.empty() || ignored_changed) {
update_state->invalidate_unignored_cached_values_ids.insert(new_data.id);
// If this ignored state had changed also invalidate the parent.
update_state->InvalidateParentNodeUnignoredCacheValues(new_data.id);
}
for (AXNodeID child_id : create_or_destroy_ids) {
if (base::Contains(new_child_id_set, child_id)) {
// This is a serious error - nodes should never be reparented without
// first being removed from the tree. If a node exists in the tree already
// then adding it to a new parent would mean stealing the node from its
// old parent which hadn't been updated to reflect the change.
if (update_state->ShouldPendingNodeExistInTree(child_id)) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kReparent);
RecordError(base::StringPrintf(
"Node %d is not marked for destruction, would be reparented to %d",
child_id, new_data.id));
return false;
}
// If a |child_id| is already pending for creation, then it must be a
// duplicate entry in the tree.
update_state->invalidate_unignored_cached_values_ids.insert(child_id);
if (!update_state->IncrementPendingCreateNodeCount(child_id,
new_data.id)) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kCreationPendingForChild);
RecordError(base::StringPrintf(
"Node %d is already pending for creation, cannot be a new child",
child_id));
return false;
}
} else {
// If |child_id| does not exist in the new set, then it has
// been removed from |node|, and the subtree must be deleted.
MarkSubtreeForDestruction(child_id, update_state);
}
}
update_state->SetLastKnownPendingNodeData(&new_data);
return true;
}
bool AXTree::UpdateNode(const AXNodeData& src,
bool is_new_root,
AXTreeUpdateState* update_state) {
DCHECK(GetTreeUpdateInProgressState());
// This method updates one node in the tree based on serialized data
// received in an AXTreeUpdate. See AXTreeUpdate for pre and post
// conditions.
// Look up the node by id. If it's not found, then either the root
// of the tree is being swapped, or we're out of sync with the source
// and this is a serious error.
AXNode* node = GetFromId(src.id);
if (node) {
update_state->pending_nodes.erase(node->id());
UpdateReverseRelations(node, src);
if (!update_state->IsCreatedNode(node) ||
update_state->IsReparentedNode(node)) {
update_state->old_node_id_to_data.insert(
std::make_pair(node->id(), node->TakeData()));
}
node->SetData(src);
} else {
if (!is_new_root) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kNotInTree);
RecordError(base::StringPrintf(
"%d is not in the tree and not the new root", src.id));
return false;
}
node = CreateNode(nullptr, src.id, 0, update_state);
UpdateReverseRelations(node, src);
node->SetData(src);
}
// If we come across a page breaking object, mark the tree as a paginated root
if (src.GetBoolAttribute(ax::mojom::BoolAttribute::kIsPageBreakingObject))
has_pagination_support_ = true;
update_state->node_data_changed_ids.insert(node->id());
// First, delete nodes that used to be children of this node but aren't
// anymore.
DeleteOldChildren(node, src.child_ids, update_state);
// Now build a new children vector, reusing nodes when possible,
// and swap it in.
std::vector<AXNode*> new_children;
bool success = CreateNewChildVector(
node, src.child_ids, &new_children, update_state);
node->SwapChildren(&new_children);
// Update the root of the tree if needed.
if (is_new_root) {
// Make sure root_ always points to something valid or null_, even inside
// DestroySubtree.
AXNode* old_root = root_;
root_ = node;
if (old_root && old_root != node)
DestroySubtree(old_root, update_state);
}
return success;
}
void AXTree::NotifySubtreeWillBeReparentedOrDeleted(
AXNode* node,
const AXTreeUpdateState* update_state) {
DCHECK(!GetTreeUpdateInProgressState());
if (node->id() == kInvalidAXNodeID)
return;
for (AXTreeObserver& observer : observers_) {
if (update_state->IsReparentedNode(node)) {
observer.OnSubtreeWillBeReparented(this, node);
} else {
observer.OnSubtreeWillBeDeleted(this, node);
}
}
}
void AXTree::NotifyNodeWillBeReparentedOrDeleted(
AXNode* node,
const AXTreeUpdateState* update_state) {
DCHECK(!GetTreeUpdateInProgressState());
AXNodeID id = node->id();
if (id == kInvalidAXNodeID)
return;
table_info_map_.erase(id);
for (AXTreeObserver& observer : observers_) {
if (update_state->IsReparentedNode(node)) {
observer.OnNodeWillBeReparented(this, node);
} else {
observer.OnNodeWillBeDeleted(this, node);
}
}
DCHECK(table_info_map_.find(id) == table_info_map_.end())
<< "Table info should never be recreated during node deletion";
}
void AXTree::RecursivelyNotifyNodeDeletedForTreeTeardown(AXNode* node) {
DCHECK(!GetTreeUpdateInProgressState());
if (node->id() == kInvalidAXNodeID)
return;
for (AXTreeObserver& observer : observers_)
observer.OnNodeDeleted(this, node->id());
for (auto* child : node->children())
RecursivelyNotifyNodeDeletedForTreeTeardown(child);
}
void AXTree::NotifyNodeHasBeenDeleted(AXNodeID node_id) {
DCHECK(!GetTreeUpdateInProgressState());
if (node_id == kInvalidAXNodeID)
return;
for (AXTreeObserver& observer : observers_)
observer.OnNodeDeleted(this, node_id);
}
void AXTree::NotifyNodeHasBeenReparentedOrCreated(
AXNode* node,
const AXTreeUpdateState* update_state) {
DCHECK(!GetTreeUpdateInProgressState());
if (node->id() == kInvalidAXNodeID)
return;
for (AXTreeObserver& observer : observers_) {
if (update_state->IsReparentedNode(node)) {
observer.OnNodeReparented(this, node);
} else {
observer.OnNodeCreated(this, node);
}
}
}
void AXTree::NotifyNodeDataWillChange(const AXNodeData& old_data,
const AXNodeData& new_data) {
DCHECK(!GetTreeUpdateInProgressState());
if (new_data.id == kInvalidAXNodeID)
return;
for (AXTreeObserver& observer : observers_)
observer.OnNodeDataWillChange(this, old_data, new_data);
}
void AXTree::NotifyNodeDataHasBeenChanged(AXNode* node,
const AXNodeData& old_data,
const AXNodeData& new_data) {
DCHECK(!GetTreeUpdateInProgressState());
if (node->id() == kInvalidAXNodeID)
return;
for (AXTreeObserver& observer : observers_)
observer.OnNodeDataChanged(this, old_data, new_data);
if (old_data.role != new_data.role) {
for (AXTreeObserver& observer : observers_)
observer.OnRoleChanged(this, node, old_data.role, new_data.role);
}
if (old_data.state != new_data.state) {
for (int32_t i = static_cast<int32_t>(ax::mojom::State::kNone) + 1;
i <= static_cast<int32_t>(ax::mojom::State::kMaxValue); ++i) {
ax::mojom::State state = static_cast<ax::mojom::State>(i);
if (old_data.HasState(state) != new_data.HasState(state)) {
for (AXTreeObserver& observer : observers_)
observer.OnStateChanged(this, node, state, new_data.HasState(state));
}
}
}
auto string_callback = [this, node](ax::mojom::StringAttribute attr,
const std::string& old_string,
const std::string& new_string) {
for (AXTreeObserver& observer : observers_) {
observer.OnStringAttributeChanged(this, node, attr, old_string,
new_string);
}
};
CallIfAttributeValuesChanged(old_data.string_attributes,
new_data.string_attributes, std::string(),
string_callback);
auto bool_callback = [this, node](ax::mojom::BoolAttribute attr,
const bool& old_bool,
const bool& new_bool) {
for (AXTreeObserver& observer : observers_)
observer.OnBoolAttributeChanged(this, node, attr, new_bool);
};
CallIfAttributeValuesChanged(old_data.bool_attributes,
new_data.bool_attributes, false, bool_callback);
auto float_callback = [this, node](ax::mojom::FloatAttribute attr,
const float& old_float,
const float& new_float) {
for (AXTreeObserver& observer : observers_)
observer.OnFloatAttributeChanged(this, node, attr, old_float, new_float);
};
CallIfAttributeValuesChanged(old_data.float_attributes,
new_data.float_attributes, 0.0f, float_callback);
auto int_callback = [this, node](ax::mojom::IntAttribute attr,
const int& old_int, const int& new_int) {
for (AXTreeObserver& observer : observers_)
observer.OnIntAttributeChanged(this, node, attr, old_int, new_int);
};
CallIfAttributeValuesChanged(old_data.int_attributes, new_data.int_attributes,
0, int_callback);
auto intlist_callback = [this, node](
ax::mojom::IntListAttribute attr,
const std::vector<int32_t>& old_intlist,
const std::vector<int32_t>& new_intlist) {
for (AXTreeObserver& observer : observers_)
observer.OnIntListAttributeChanged(this, node, attr, old_intlist,
new_intlist);
};
CallIfAttributeValuesChanged(old_data.intlist_attributes,
new_data.intlist_attributes,
std::vector<int32_t>(), intlist_callback);
auto stringlist_callback =
[this, node](ax::mojom::StringListAttribute attr,
const std::vector<std::string>& old_stringlist,
const std::vector<std::string>& new_stringlist) {
for (AXTreeObserver& observer : observers_)
observer.OnStringListAttributeChanged(this, node, attr,
old_stringlist, new_stringlist);
};
CallIfAttributeValuesChanged(old_data.stringlist_attributes,
new_data.stringlist_attributes,
std::vector<std::string>(), stringlist_callback);
}
void AXTree::UpdateReverseRelations(AXNode* node, const AXNodeData& new_data) {
DCHECK(GetTreeUpdateInProgressState());
const AXNodeData& old_data = node->data();
int id = new_data.id;
auto int_callback = [this, id](ax::mojom::IntAttribute attr,
const int& old_id, const int& new_id) {
if (!IsNodeIdIntAttribute(attr))
return;
// Remove old_id -> id from the map, and clear map keys if their
// values are now empty.
auto& map = int_reverse_relations_[attr];
if (map.find(old_id) != map.end()) {
map[old_id].erase(id);
if (map[old_id].empty())
map.erase(old_id);
}
// Add new_id -> id to the map, unless new_id is zero indicating that
// we're only removing a relation.
if (new_id)
map[new_id].insert(id);
};
CallIfAttributeValuesChanged(old_data.int_attributes, new_data.int_attributes,
0, int_callback);
auto intlist_callback = [this, id](ax::mojom::IntListAttribute attr,
const std::vector<int32_t>& old_idlist,
const std::vector<int32_t>& new_idlist) {
if (!IsNodeIdIntListAttribute(attr))
return;
auto& map = intlist_reverse_relations_[attr];
for (AXNodeID old_id : old_idlist) {
if (map.find(old_id) != map.end()) {
map[old_id].erase(id);
if (map[old_id].empty())
map.erase(old_id);
}
}
for (AXNodeID new_id : new_idlist)
intlist_reverse_relations_[attr][new_id].insert(id);
};
CallIfAttributeValuesChanged(old_data.intlist_attributes,
new_data.intlist_attributes,
std::vector<AXNodeID>(), intlist_callback);
auto string_callback = [this, id](ax::mojom::StringAttribute attr,
const std::string& old_string,
const std::string& new_string) {
if (attr == ax::mojom::StringAttribute::kChildTreeId) {
// Remove old_string -> id from the map, and clear map keys if
// their values are now empty.
AXTreeID old_ax_tree_id = AXTreeID::FromString(old_string);
if (child_tree_id_reverse_map_.find(old_ax_tree_id) !=
child_tree_id_reverse_map_.end()) {
child_tree_id_reverse_map_[old_ax_tree_id].erase(id);
if (child_tree_id_reverse_map_[old_ax_tree_id].empty())
child_tree_id_reverse_map_.erase(old_ax_tree_id);
}
// Add new_string -> id to the map, unless new_id is zero indicating that
// we're only removing a relation.
if (!new_string.empty()) {
AXTreeID new_ax_tree_id = AXTreeID::FromString(new_string);
child_tree_id_reverse_map_[new_ax_tree_id].insert(id);
}
}
};
CallIfAttributeValuesChanged(old_data.string_attributes,
new_data.string_attributes, std::string(),
string_callback);
}
bool AXTree::ValidatePendingChangesComplete(
const AXTreeUpdateState& update_state) {
if (!update_state.pending_nodes.empty()) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kPendingNodes);
std::string error = "Nodes left pending by the update:";
for (const AXNodeID pending_id : update_state.pending_nodes)
error += base::StringPrintf(" %d", pending_id);
RecordError(error);
return false;
}
if (!update_state.node_id_to_pending_data.empty()) {
std::string destroy_subtree_ids;
std::string destroy_node_ids;
std::string create_node_ids;
bool has_pending_changes = false;
for (auto&& pair : update_state.node_id_to_pending_data) {
const AXNodeID pending_id = pair.first;
const std::unique_ptr<PendingStructureChanges>& data = pair.second;
if (data->DoesNodeExpectAnyStructureChanges()) {
if (data->DoesNodeExpectSubtreeWillBeDestroyed())
destroy_subtree_ids += base::StringPrintf(" %d", pending_id);
if (data->DoesNodeExpectNodeWillBeDestroyed())
destroy_node_ids += base::StringPrintf(" %d", pending_id);
if (data->DoesNodeExpectNodeWillBeCreated())
create_node_ids += base::StringPrintf(" %d", pending_id);
has_pending_changes = true;
}
}
if (has_pending_changes) {
ACCESSIBILITY_TREE_UNSERIALIZE_ERROR_HISTOGRAM(
AXTreeUnserializeError::kPendingChanges);
RecordError(base::StringPrintf(
"Changes left pending by the update; "
"destroy subtrees: %s, destroy nodes: %s, create nodes: %s",
destroy_subtree_ids.c_str(), destroy_node_ids.c_str(),
create_node_ids.c_str()));
}
return !has_pending_changes;
}
return true;
}
void AXTree::MarkSubtreeForDestruction(AXNodeID node_id,
AXTreeUpdateState* update_state) {
update_state->IncrementPendingDestroySubtreeCount(node_id);
MarkNodesForDestructionRecursive(node_id, update_state);
}
void AXTree::MarkNodesForDestructionRecursive(AXNodeID node_id,
AXTreeUpdateState* update_state) {
// If this subtree has already been marked for destruction, return so
// we don't walk it again.
if (!update_state->ShouldPendingNodeExistInTree(node_id))
return;
const AXNodeData& last_known_data =
update_state->GetLastKnownPendingNodeData(node_id);
update_state->IncrementPendingDestroyNodeCount(node_id);
for (AXNodeID child_id : last_known_data.child_ids) {
MarkNodesForDestructionRecursive(child_id, update_state);
}
}
void AXTree::DestroySubtree(AXNode* node,
AXTreeUpdateState* update_state) {
DCHECK(GetTreeUpdateInProgressState());
// |update_state| must already contain information about all of the expected
// changes and invalidations to apply. If any of these are missing, observers
// may not be notified of changes.
DCHECK(update_state);
DCHECK_GT(update_state->GetPendingDestroySubtreeCount(node->id()), 0);
DCHECK(!node->parent() ||
update_state->InvalidatesUnignoredCachedValues(node->parent()->id()));
update_state->DecrementPendingDestroySubtreeCount(node->id());
DestroyNodeAndSubtree(node, update_state);
}
void AXTree::DestroyNodeAndSubtree(AXNode* node,
AXTreeUpdateState* update_state) {
DCHECK(GetTreeUpdateInProgressState());
DCHECK(!update_state ||
update_state->GetPendingDestroyNodeCount(node->id()) > 0);
// Clear out any reverse relations.
AXNodeData empty_data;
empty_data.id = node->id();
UpdateReverseRelations(node, empty_data);
id_map_.erase(node->id());
for (auto* child : node->children())
DestroyNodeAndSubtree(child, update_state);
if (update_state) {
update_state->pending_nodes.erase(node->id());
update_state->DecrementPendingDestroyNodeCount(node->id());
update_state->removed_node_ids.insert(node->id());
update_state->new_node_ids.erase(node->id());
update_state->node_data_changed_ids.erase(node->id());
if (update_state->IsReparentedNode(node)) {
update_state->old_node_id_to_data.emplace(
std::make_pair(node->id(), node->TakeData()));
}
}
node->Destroy();
}
void AXTree::DeleteOldChildren(AXNode* node,
const std::vector<AXNodeID>& new_child_ids,
AXTreeUpdateState* update_state) {
DCHECK(GetTreeUpdateInProgressState());
// Create a set of child ids in |src| for fast lookup, we know the set does
// not contain duplicate entries already, because that was handled when
// populating |update_state| with information about all of the expected
// changes to be applied.
std::set<AXNodeID> new_child_id_set(new_child_ids.begin(),
new_child_ids.end());
// Delete the old children.
for (AXNode* child : node->children()) {
if (!base::Contains(new_child_id_set, child->id()))
DestroySubtree(child, update_state);
}
}
bool AXTree::CreateNewChildVector(AXNode* node,
const std::vector<AXNodeID>& new_child_ids,
std::vector<AXNode*>* new_children,
AXTreeUpdateState* update_state) {
DCHECK(GetTreeUpdateInProgressState());
bool success = true;
for (size_t i = 0; i < new_child_ids.size(); ++i) {
AXNodeID child_id = new_child_ids[i];
AXNode* child = GetFromId(child_id);
if (child) {
if (child->parent() != node) {
// This is a serious error - nodes should never be reparented.
// If this case occurs, continue so this node isn't left in an
// inconsistent state, but return failure at the end.
if (child->parent()) {
RecordError(base::StringPrintf("Node %d reparented from %d to %d",
child->id(), child->parent()->id(),
node->id()));
} else {
// --- Begin temporary change ---
// TODO(crbug.com/1156601) Revert this once we have the crash data we
// need (crrev.com/c/2892259)
// Diagnose strange errors "Node 1 reparented from 0 to 2", which
// sounds like the root node is getting the <html> element as a parent
// -- in the normal case, the root is 1 and <html> is 2.
std::ostringstream error;
error << "Node did not have a previous parent, but "
"reparenting error triggered:"
<< "\n* Child = " << *child << "\n* New parent = " << *node
<< "\n* root_will_be_created = "
<< update_state->root_will_be_created
<< "\n* pending_root_id = "
<< (update_state->pending_root_id
? *update_state->pending_root_id
: kInvalidAXNodeID)
<< "\nTree update: "
<< update_state->pending_tree_update.ToString();
// Add the error message to "breadcrumbs" in crash reports:
base::debug::ScopedActivity scoped_activity;
base::debug::ActivityUserData& user_data =
scoped_activity.user_data();
user_data.SetString("ax_reparenting_error", error.str());
CHECK(false) << error.str();
// --- End temporary change ---
}
success = false;
continue;
}
child->SetIndexInParent(i);
} else {
child = CreateNode(node, child_id, i, update_state);
update_state->pending_nodes.insert(child->id());
}
new_children->push_back(child);
}
return success;
}
AXNodeID AXTree::GetNextNegativeInternalNodeId() {
AXNodeID return_value = next_negative_internal_node_id_;
next_negative_internal_node_id_--;
if (next_negative_internal_node_id_ > 0)
next_negative_internal_node_id_ = -1;
return return_value;
}
void AXTree::PopulateOrderedSetItemsMap(
const AXNode& original_node,
const AXNode* ordered_set,
OrderedSetItemsMap* items_map_to_be_populated) const {
// Ignored nodes are not a part of ordered sets.
if (original_node.IsIgnored())
return;
// Not all ordered set containers support hierarchical level, but their set
// items may support hierarchical level. For example, container <tree> does
// not support level, but <treeitem> supports level. For ordered sets like
// this, the set container (e.g. <tree>) will take on the min of the levels
// of its direct children(e.g. <treeitem>), if the children's levels are
// defined.
absl::optional<int> ordered_set_min_level =
ordered_set->GetHierarchicalLevel();
for (AXNode::UnignoredChildIterator child =
ordered_set->UnignoredChildrenBegin();
child != ordered_set->UnignoredChildrenEnd(); ++child) {
absl::optional<int> child_level = child->GetHierarchicalLevel();
if (child_level) {
ordered_set_min_level = ordered_set_min_level
? std::min(child_level, ordered_set_min_level)
: child_level;
}
}
RecursivelyPopulateOrderedSetItemsMap(original_node, ordered_set, ordered_set,
ordered_set_min_level, absl::nullopt,
items_map_to_be_populated);
// If after RecursivelyPopulateOrderedSetItemsMap() call, the corresponding
// level (i.e. |ordered_set_min_level|) does not exist in
// |items_map_to_be_populated|, and |original_node| equals |ordered_set|, we
// know |original_node| is an empty ordered set and contains no set items.
// However, |original_node| may still have set size attribute, so we still
// want to add this empty set (i.e. original_node/ordered_set) to
// |items_map_to_be_populated|.
if (&original_node == ordered_set &&
!items_map_to_be_populated->HierarchicalLevelExists(
ordered_set_min_level)) {
items_map_to_be_populated->Add(ordered_set_min_level,
OrderedSetContent(&original_node));
}
}
void AXTree::RecursivelyPopulateOrderedSetItemsMap(
const AXNode& original_node,
const AXNode* ordered_set,
const AXNode* local_parent,
absl::optional<int> ordered_set_min_level,
absl::optional<int> prev_level,
OrderedSetItemsMap* items_map_to_be_populated) const {
// For optimization purpose, we want to only populate set items that are
// direct descendants of |ordered_set|, since we will only be calculating
// PosInSet & SetSize of items of that level. So we skip items on deeper
// levels by stop searching recursively on node |local_parent| that turns out
// to be an ordered set whose role matches that of |ordered_set|. However,
// when we encounter a flattened structure such as the following:
// <div role="tree">
// <div role="treeitem" aria-level="1"></div>
// <div role="treeitem" aria-level="2"></div>
// <div role="treeitem" aria-level="3"></div>
// </div>
// This optimization won't apply, we will end up populating items from all
// levels.
if (ordered_set->data().role == local_parent->data().role &&
ordered_set != local_parent)
return;
for (AXNode::UnignoredChildIterator itr =
local_parent->UnignoredChildrenBegin();
itr != local_parent->UnignoredChildrenEnd(); ++itr) {
const AXNode* child = itr.get();
// Invisible children should not be counted.
// However, in the collapsed container case (e.g. a combobox), items can
// still be chosen/navigated. However, the options in these collapsed
// containers are historically marked invisible. Therefore, in that case,
// count the invisible items. Only check 2 levels up, as combobox containers
// are never higher.
if (child->data().HasState(ax::mojom::State::kInvisible) &&
!IsCollapsed(local_parent) && !IsCollapsed(local_parent->parent())) {
continue;
}
absl::optional<int> curr_level = child->GetHierarchicalLevel();
// Add child to |items_map_to_be_populated| if role matches with the role of
// |ordered_set|. If role of node is kRadioButton, don't add items of other
// roles, even if item role matches the role of |ordered_set|.
if (child->data().role == ax::mojom::Role::kComment ||
(original_node.data().role == ax::mojom::Role::kRadioButton &&
child->data().role == ax::mojom::Role::kRadioButton) ||
(original_node.data().role != ax::mojom::Role::kRadioButton &&
child->SetRoleMatchesItemRole(ordered_set))) {
// According to WAI-ARIA spec, some ordered set items do not support
// hierarchical level while its ordered set container does. For example,
// <tab> does not support level, while <tablist> supports level.
// https://www.w3.org/WAI/PF/aria/roles#tab
// https://www.w3.org/WAI/PF/aria/roles#tablist
// For this special case, when we add set items (e.g. tab) to
// |items_map_to_be_populated|, set item is placed at the same level as
// its container (e.g. tablist) in |items_map_to_be_populated|.
if (!curr_level && child->GetUnignoredParent() == ordered_set)
curr_level = ordered_set_min_level;
// We only add child to |items_map_to_be_populated| if the child set item
// is at the same hierarchical level as |ordered_set|'s level.
if (!items_map_to_be_populated->HierarchicalLevelExists(curr_level)) {
bool use_ordered_set = child->SetRoleMatchesItemRole(ordered_set) &&
ordered_set_min_level == curr_level;
const AXNode* child_ordered_set =
use_ordered_set ? ordered_set : nullptr;
items_map_to_be_populated->Add(curr_level,
OrderedSetContent(child_ordered_set));
}
items_map_to_be_populated->AddItemToBack(curr_level, child);
}
// If |child| is an ignored container for ordered set and should not be used
// to contribute to |items_map_to_be_populated|, we recurse into |child|'s
// descendants to populate |items_map_to_be_populated|.
if (child->IsIgnoredContainerForOrderedSet()) {
RecursivelyPopulateOrderedSetItemsMap(original_node, ordered_set, child,
ordered_set_min_level, curr_level,
items_map_to_be_populated);
}
// If |curr_level| goes up one level from |prev_level|, which indicates
// the ordered set of |prev_level| is closed, we add a new OrderedSetContent
// on the previous level of |items_map_to_be_populated| to signify this.
// Consider the example below:
// <div role="tree">
// <div role="treeitem" aria-level="1"></div>
// <!--- set1-level2 -->
// <div role="treeitem" aria-level="2"></div>
// <div role="treeitem" aria-level="2"></div> <--|prev_level|
// <div role="treeitem" aria-level="1" id="item2-level1"> <--|curr_level|
// </div>
// <!--- set2-level2 -->
// <div role="treeitem" aria-level="2"></div>
// <div role="treeitem" aria-level="2"></div>
// </div>
// |prev_level| is on the last item of "set1-level2" and |curr_level| is on
// "item2-level1". Since |curr_level| is up one level from |prev_level|, we
// already completed adding all items from "set1-level2" to
// |items_map_to_be_populated|. So we close up "set1-level2" by adding a new
// OrderedSetContent to level 2. When |curr_level| ends up on the items of
// "set2-level2" next, it has a fresh new set to be populated.
if (child->SetRoleMatchesItemRole(ordered_set) && curr_level < prev_level)
items_map_to_be_populated->Add(prev_level, OrderedSetContent());
prev_level = curr_level;
}
}
// Given an ordered_set, compute pos_in_set and set_size for all of its items
// and store values in cache.
// Ordered_set should never be nullptr.
void AXTree::ComputeSetSizePosInSetAndCache(const AXNode& node,
const AXNode* ordered_set) {
DCHECK(ordered_set);
// Set items role::kComment and role::kRadioButton are special cases and do
// not necessarily need to be contained in an ordered set.
if (node.data().role != ax::mojom::Role::kComment &&
node.data().role != ax::mojom::Role::kRadioButton &&
!node.SetRoleMatchesItemRole(ordered_set) && !IsSetLike(node.data().role))
return;
// Find all items within ordered_set and add to |items_map_to_be_populated|.
OrderedSetItemsMap items_map_to_be_populated;
PopulateOrderedSetItemsMap(node, ordered_set, &items_map_to_be_populated);
// If ordered_set role is kPopUpButton and it wraps a kMenuListPopUp, then we
// would like it to inherit the SetSize from the kMenuListPopUp it wraps. To
// do this, we treat the kMenuListPopUp as the ordered_set and eventually
// assign its SetSize value to the kPopUpButton.
if (node.data().role == ax::mojom::Role::kPopUpButton &&
node.GetUnignoredChildCount() > 0) {
// kPopUpButtons are only allowed to contain one kMenuListPopUp.
// The single element is guaranteed to be a kMenuListPopUp because that is
// the only item role that matches the ordered set role of kPopUpButton.
// Please see AXNode::SetRoleMatchesItemRole for more details.
OrderedSetContent* set_content =
items_map_to_be_populated.GetFirstOrderedSetContent();
if (set_content && set_content->set_items_.size() == 1) {
const AXNode* menu_list_popup = set_content->set_items_.front();
if (menu_list_popup->data().role == ax::mojom::Role::kMenuListPopup) {
items_map_to_be_populated.Clear();
PopulateOrderedSetItemsMap(node, menu_list_popup,
&items_map_to_be_populated);
set_content = items_map_to_be_populated.GetFirstOrderedSetContent();
// Replace |set_content|'s ordered set container with |node|
// (Role::kPopUpButton), which acts as the set container for nodes with
// Role::kMenuListOptions (children of |menu_list_popup|).
if (set_content)
set_content->ordered_set_ = &node;
}
}
}
// Iterate over all items from OrderedSetItemsMap to compute and cache each
// ordered set item's PosInSet and SetSize and corresponding ordered set
// container's SetSize.
for (auto element : items_map_to_be_populated.items_map_) {
for (const OrderedSetContent& ordered_set_content : element.second) {
ComputeSetSizePosInSetAndCacheHelper(ordered_set_content);
}
}
}
void AXTree::ComputeSetSizePosInSetAndCacheHelper(
const OrderedSetContent& ordered_set_content) {
// Keep track of number of items in the set.
int32_t num_elements = 0;
// Keep track of largest ordered set item's |aria-setsize| attribute value.
int32_t max_item_set_size_from_attribute = 0;
for (const AXNode* item : ordered_set_content.set_items_) {
// |item|'s PosInSet value is the maximum of accumulated number of
// elements count and the value from its |aria-posinset| attribute.
int32_t pos_in_set_value =
std::max(num_elements + 1,
item->GetIntAttribute(ax::mojom::IntAttribute::kPosInSet));
// For |item| that has defined hierarchical level and |aria-posinset|
// attribute, the attribute value takes precedence.
// Note: According to WAI-ARIA spec, items that support
// |aria-posinset| do not necessarily support hierarchical level.
if (item->GetHierarchicalLevel() &&
item->HasIntAttribute(ax::mojom::IntAttribute::kPosInSet))
pos_in_set_value =
item->GetIntAttribute(ax::mojom::IntAttribute::kPosInSet);
num_elements = pos_in_set_value;
// Cache computed PosInSet value for |item|.
node_set_size_pos_in_set_info_map_[item->id()] = NodeSetSizePosInSetInfo();
node_set_size_pos_in_set_info_map_[item->id()].pos_in_set =
pos_in_set_value;
// Track the largest set size for this OrderedSetContent.
max_item_set_size_from_attribute =
std::max(max_item_set_size_from_attribute,
item->GetIntAttribute(ax::mojom::IntAttribute::kSetSize));
} // End of iterating over each item in |ordered_set_content|.
// The SetSize of an ordered set (and all of its items) is the maximum of
// the following values:
// 1. The number of elements in the ordered set.
// 2. The largest item set size from |aria-setsize| attribute.
// 3. The ordered set container's |aria-setsize| attribute value.
int32_t set_size_value =
std::max(num_elements, max_item_set_size_from_attribute);
// Cache the hierarchical level and set size of |ordered_set_content|'s set
// container, if the container exists.
if (const AXNode* ordered_set = ordered_set_content.ordered_set_) {
set_size_value = std::max(
set_size_value,
ordered_set->GetIntAttribute(ax::mojom::IntAttribute::kSetSize));
// Cache |ordered_set|'s hierarchical level.
absl::optional<int> ordered_set_level = ordered_set->GetHierarchicalLevel();
if (node_set_size_pos_in_set_info_map_.find(ordered_set->id()) ==
node_set_size_pos_in_set_info_map_.end()) {
node_set_size_pos_in_set_info_map_[ordered_set->id()] =
NodeSetSizePosInSetInfo();
node_set_size_pos_in_set_info_map_[ordered_set->id()]
.lowest_hierarchical_level = ordered_set_level;
} else if (node_set_size_pos_in_set_info_map_[ordered_set->id()]
.lowest_hierarchical_level > ordered_set_level) {
node_set_size_pos_in_set_info_map_[ordered_set->id()]
.lowest_hierarchical_level = ordered_set_level;
}
// Cache |ordered_set|'s set size.
node_set_size_pos_in_set_info_map_[ordered_set->id()].set_size =
set_size_value;
}
// Cache the set size of |ordered_set_content|'s set items.
for (const AXNode* item : ordered_set_content.set_items_) {
// If item's hierarchical level and |aria-setsize| attribute are specified,
// the item's |aria-setsize| value takes precedence.
if (item->GetHierarchicalLevel() &&
item->HasIntAttribute(ax::mojom::IntAttribute::kSetSize))
node_set_size_pos_in_set_info_map_[item->id()].set_size =
item->GetIntAttribute(ax::mojom::IntAttribute::kSetSize);
else
node_set_size_pos_in_set_info_map_[item->id()].set_size = set_size_value;
} // End of iterating over each item in |ordered_set_content|.
}
absl::optional<int> AXTree::GetPosInSet(const AXNode& node) {
if (node.data().role == ax::mojom::Role::kPopUpButton &&
node.GetUnignoredChildCount() == 0 &&
node.HasIntAttribute(ax::mojom::IntAttribute::kPosInSet)) {
return node.GetIntAttribute(ax::mojom::IntAttribute::kPosInSet);
}
if (node_set_size_pos_in_set_info_map_.find(node.id()) !=
node_set_size_pos_in_set_info_map_.end()) {
// If item's id is in the cache, return stored PosInSet value.
return node_set_size_pos_in_set_info_map_[node.id()].pos_in_set;
}
if (GetTreeUpdateInProgressState())
return absl::nullopt;
// Only allow this to be called on nodes that can hold PosInSet values,
// which are defined in the ARIA spec.
if (!node.IsOrderedSetItem() || node.IsIgnored())
return absl::nullopt;
const AXNode* ordered_set = node.GetOrderedSet();
if (!ordered_set)
return absl::nullopt;
// Compute, cache, then return.
ComputeSetSizePosInSetAndCache(node, ordered_set);
absl::optional<int> pos_in_set =
node_set_size_pos_in_set_info_map_[node.id()].pos_in_set;
if (pos_in_set.has_value() && pos_in_set.value() < 1)
return absl::nullopt;
return pos_in_set;
}
absl::optional<int> AXTree::GetSetSize(const AXNode& node) {
if (node.data().role == ax::mojom::Role::kPopUpButton &&
node.GetUnignoredChildCount() == 0 &&
node.HasIntAttribute(ax::mojom::IntAttribute::kSetSize)) {
return node.GetIntAttribute(ax::mojom::IntAttribute::kSetSize);
}
if (node_set_size_pos_in_set_info_map_.find(node.id()) !=
node_set_size_pos_in_set_info_map_.end()) {
// If item's id is in the cache, return stored SetSize value.
return node_set_size_pos_in_set_info_map_[node.id()].set_size;
}
if (GetTreeUpdateInProgressState())
return absl::nullopt;
// Only allow this to be called on nodes that can hold SetSize values, which
// are defined in the ARIA spec. However, we allow set-like items to receive
// SetSize values for internal purposes.
if ((!node.IsOrderedSetItem() && !node.IsOrderedSet()) || node.IsIgnored() ||
node.IsEmbeddedGroup()) {
return absl::nullopt;
}
// If |node| is item-like, find its outerlying ordered set. Otherwise,
// |node| is the ordered set.
const AXNode* ordered_set = &node;
if (IsItemLike(node.data().role))
ordered_set = node.GetOrderedSet();
if (!ordered_set)
return absl::nullopt;
// For popup buttons that control a single element, inherit the controlled
// item's SetSize. Skip this block if the popup button controls itself.
if (node.data().role == ax::mojom::Role::kPopUpButton) {
const auto& controls_ids = node.data().GetIntListAttribute(
ax::mojom::IntListAttribute::kControlsIds);
if (controls_ids.size() == 1 && GetFromId(controls_ids[0]) &&
controls_ids[0] != node.id()) {
const AXNode& controlled_item = *GetFromId(controls_ids[0]);
absl::optional<int> controlled_item_set_size =
GetSetSize(controlled_item);
node_set_size_pos_in_set_info_map_[node.id()].set_size =
controlled_item_set_size;
return controlled_item_set_size;
}
}
// Compute, cache, then return.
ComputeSetSizePosInSetAndCache(node, ordered_set);
absl::optional<int> set_size =
node_set_size_pos_in_set_info_map_[node.id()].set_size;
if (set_size.has_value() && set_size.value() < 0)
return absl::nullopt;
return set_size;
}
AXTree::Selection AXTree::GetUnignoredSelection() const {
Selection unignored_selection = {
data().sel_is_backward, data().sel_anchor_object_id,
data().sel_anchor_offset, data().sel_anchor_affinity,
data().sel_focus_object_id, data().sel_focus_offset,
data().sel_focus_affinity};
AXNode* anchor_node = GetFromId(data().sel_anchor_object_id);
AXNode* focus_node = GetFromId(data().sel_focus_object_id);
AXNodePosition::AXPositionInstance anchor_position =
anchor_node ? AXNodePosition::CreatePosition(*anchor_node,
data().sel_anchor_offset,
data().sel_anchor_affinity)
: AXNodePosition::CreateNullPosition();
// Null positions are never ignored.
if (anchor_position->IsIgnored()) {
anchor_position = anchor_position->AsUnignoredPosition(
data().sel_is_backward ? AXPositionAdjustmentBehavior::kMoveForward
: AXPositionAdjustmentBehavior::kMoveBackward);
// Moving to an unignored position might have placed the position on a leaf
// node. Any selection endpoint that is inside a leaf node is expressed as a
// text position in AXTreeData. (Note that in this context "leaf node" means
// a node with no children or with only ignored children. This does not
// refer to a platform leaf.)
if (anchor_position->IsLeafTreePosition())
anchor_position = anchor_position->AsTextPosition();
// We do not expect the selection to have an endpoint on an inline text
// box as this will create issues with parts of the code that don't use
// inline text boxes.
if (anchor_position->IsTextPosition() &&
anchor_position->GetAnchor()->data().role ==
ax::mojom::Role::kInlineTextBox) {
anchor_position = anchor_position->CreateParentPosition();
}
switch (anchor_position->kind()) {
case AXPositionKind::NULL_POSITION:
// If one of the selection endpoints is invalid, then both endpoints
// should be unset.
unignored_selection.anchor_object_id = kInvalidAXNodeID;
unignored_selection.anchor_offset = -1;
unignored_selection.anchor_affinity =
ax::mojom::TextAffinity::kDownstream;
unignored_selection.focus_object_id = kInvalidAXNodeID;
unignored_selection.focus_offset = -1;
unignored_selection.focus_affinity =
ax::mojom::TextAffinity::kDownstream;
return unignored_selection;
case AXPositionKind::TREE_POSITION:
unignored_selection.anchor_object_id = anchor_position->anchor_id();
unignored_selection.anchor_offset = anchor_position->child_index();
unignored_selection.anchor_affinity =
ax::mojom::TextAffinity::kDownstream;
break;
case AXPositionKind::TEXT_POSITION:
unignored_selection.anchor_object_id = anchor_position->anchor_id();
unignored_selection.anchor_offset = anchor_position->text_offset();
unignored_selection.anchor_affinity = anchor_position->affinity();
break;
}
}
AXNodePosition::AXPositionInstance focus_position =
focus_node
? AXNodePosition::CreatePosition(*focus_node, data().sel_focus_offset,
data().sel_focus_affinity)
: AXNodePosition::CreateNullPosition();
// Null positions are never ignored.
if (focus_position->IsIgnored()) {
focus_position = focus_position->AsUnignoredPosition(
!data().sel_is_backward ? AXPositionAdjustmentBehavior::kMoveForward
: AXPositionAdjustmentBehavior::kMoveBackward);
// Moving to an unignored position might have placed the position on a leaf
// node. Any selection endpoint that is inside a leaf node is expressed as a
// text position in AXTreeData. (Note that in this context "leaf node" means
// a node with no children or with only ignored children. This does not
// refer to a platform leaf.)
if (focus_position->IsLeafTreePosition())
focus_position = focus_position->AsTextPosition();
// We do not expect the selection to have an endpoint on an inline text
// box as this will create issues with parts of the code that don't use
// inline text boxes.
if (focus_position->IsTextPosition() &&
focus_position->GetAnchor()->data().role ==
ax::mojom::Role::kInlineTextBox) {
focus_position = focus_position->CreateParentPosition();
}
switch (focus_position->kind()) {
case AXPositionKind::NULL_POSITION:
// If one of the selection endpoints is invalid, then both endpoints
// should be unset.
unignored_selection.anchor_object_id = kInvalidAXNodeID;
unignored_selection.anchor_offset = -1;
unignored_selection.anchor_affinity =
ax::mojom::TextAffinity::kDownstream;
unignored_selection.focus_object_id = kInvalidAXNodeID;
unignored_selection.focus_offset = -1;
unignored_selection.focus_affinity =
ax::mojom::TextAffinity::kDownstream;
return unignored_selection;
case AXPositionKind::TREE_POSITION:
unignored_selection.focus_object_id = focus_position->anchor_id();
unignored_selection.focus_offset = focus_position->child_index();
unignored_selection.focus_affinity =
ax::mojom::TextAffinity::kDownstream;
break;
case AXPositionKind::TEXT_POSITION:
unignored_selection.focus_object_id = focus_position->anchor_id();
unignored_selection.focus_offset = focus_position->text_offset();
unignored_selection.focus_affinity = focus_position->affinity();
break;
}
}
return unignored_selection;
}
bool AXTree::GetTreeUpdateInProgressState() const {
return tree_update_in_progress_;
}
void AXTree::SetTreeUpdateInProgressState(bool set_tree_update_value) {
tree_update_in_progress_ = set_tree_update_value;
}
bool AXTree::HasPaginationSupport() const {
return has_pagination_support_;
}
void AXTree::NotifyTreeManagerWillBeRemoved(AXTreeID previous_tree_id) {
if (previous_tree_id == AXTreeIDUnknown())
return;
for (AXTreeObserver& observer : observers_)
observer.OnTreeManagerWillBeRemoved(previous_tree_id);
}
void AXTree::RecordError(std::string new_error) {
if (!error_.empty())
error_ = error_ + "\n"; // Add visual separation between errors.
error_ = error_ + new_error;
}
} // namespace ui