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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 <numeric>
#include <set>
#include "base/auto_reset.h"
#include "base/command_line.h"
#include "base/logging.h"
#include "base/no_destructor.h"
#include "base/stl_util.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 {
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())
? base::Optional<AXNode::AXID>{node->parent()->id()}
: base::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.
base::Optional<AXNode::AXID> 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)
: pending_update_status(AXTreePendingStructureStatus::kNotStarted),
root_will_be_created(false),
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(AXNode::AXID 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(AXNode::AXID 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.
base::Optional<AXNode::AXID> GetParentIdForPendingNode(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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 = base::nullopt;
if (pending_root_id == node_id)
pending_root_id = base::nullopt;
return true;
}
// Decrements the number of times the update is expected to
// destroy a node with |node_id|.
void DecrementPendingDestroyNodeCount(AXNode::AXID 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(AXNode::AXID 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(
AXNode::AXID node_id,
base::Optional<AXNode::AXID> 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(AXNode::AXID 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(AXNode::AXID 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(AXNode::AXID 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.";
base::Optional<AXNode::AXID> 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.
base::Optional<AXNode::AXID> 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<AXNode::AXID> 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<AXNode::AXID> invalidate_unignored_cached_values_ids;
// Keeps track of nodes that have changed their node data.
std::set<AXNode::AXID> node_data_changed_ids;
// Keeps track of new nodes created during this update.
std::set<AXNode::AXID> 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<AXNode::AXID> removed_node_ids;
// Maps between a node id and its pending update information.
std::map<AXNode::AXID, 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<AXNode::AXID, AXNodeData> old_node_id_to_data;
// Optional copy of the old tree data, only populated when the tree
// data has changed.
base::Optional<AXTreeData> old_tree_data;
private:
PendingStructureChanges* GetPendingStructureChanges(
AXNode::AXID 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(
AXNode::AXID 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::AXTree() {
AXNodeData root;
root.id = AXNode::kInvalidAXID;
AXTreeUpdate initial_state;
initial_state.root_id = AXNode::kInvalidAXID;
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() {
if (root_) {
RecursivelyNotifyNodeDeletedForTreeTeardown(root_);
base::AutoReset<bool> update_state_resetter(&tree_update_in_progress_,
true);
DestroyNodeAndSubtree(root_, nullptr);
}
for (auto& entry : table_info_map_)
delete entry.second;
table_info_map_.clear();
}
void AXTree::AddObserver(AXTreeObserver* observer) {
observers_.AddObserver(observer);
}
bool AXTree::HasObserver(AXTreeObserver* observer) {
return observers_.HasObserver(observer);
}
void AXTree::RemoveObserver(const AXTreeObserver* observer) {
observers_.RemoveObserver(observer);
}
AXTreeID AXTree::GetAXTreeID() const {
return data().tree_id;
}
AXNode* AXTree::GetFromId(int32_t id) const {
auto iter = id_map_.find(id);
return iter != id_map_.end() ? iter->second : 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<int32_t> AXTree::GetReverseRelations(ax::mojom::IntAttribute attr,
int32_t 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<int32_t>();
}
std::set<int32_t> AXTree::GetReverseRelations(ax::mojom::IntListAttribute attr,
int32_t 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<int32_t>();
}
std::set<int32_t> 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<int32_t>();
}
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) {
AXTreeUpdateState update_state(*this);
const AXNode::AXID old_root_id = root_ ? root_->id() : AXNode::kInvalidAXID;
// 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;
// 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 AXNode::AXID 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<int32_t> 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 != AXNode::kInvalidAXID) {
if (AXNode* cleared_node = GetFromId(update.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_) {
error_ = "Tree has no root.";
return false;
}
if (!ValidatePendingChangesComplete(update_state))
return false;
// 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<int32_t> table_ids_checked;
for (size_t i = 0; i < update.nodes.size(); ++i) {
AXNode* node = GetFromId(update.nodes[i].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();
table_ids_checked.insert(node->id());
node = node->parent();
}
}
// Clear list_info_map_
ordered_set_info_map_.clear();
std::vector<AXTreeObserver::Change> changes;
changes.reserve(update.nodes.size());
std::set<AXNode::AXID> 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() ||