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// Copyright 2016 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 "ui/accessibility/ax_tree_combiner.h"
#include "ui/gfx/geometry/rect_f.h"
namespace ui {
namespace {
// Return true if |attr| is a node ID that would need to be mapped when
// renumbering the ids in a combined tree.
bool IsNodeIdIntAttribute(AXIntAttribute attr) {
switch (attr) {
case AX_ATTR_ACTIVEDESCENDANT_ID:
case AX_ATTR_TABLE_HEADER_ID:
case AX_ATTR_TABLE_COLUMN_HEADER_ID:
case AX_ATTR_TABLE_ROW_HEADER_ID:
return true;
// Note: all of the attributes are included here explicitly,
// rather than using "default:", so that it's a compiler error to
// add a new attribute without explicitly considering whether it's
// a node id attribute or not.
case AX_INT_ATTRIBUTE_NONE:
case AX_ATTR_SCROLL_X:
case AX_ATTR_SCROLL_X_MIN:
case AX_ATTR_SCROLL_X_MAX:
case AX_ATTR_SCROLL_Y:
case AX_ATTR_SCROLL_Y_MIN:
case AX_ATTR_SCROLL_Y_MAX:
case AX_ATTR_TEXT_SEL_START:
case AX_ATTR_TEXT_SEL_END:
case AX_ATTR_TABLE_ROW_COUNT:
case AX_ATTR_TABLE_COLUMN_COUNT:
case AX_ATTR_TABLE_ROW_INDEX:
case AX_ATTR_TABLE_COLUMN_INDEX:
case AX_ATTR_TABLE_CELL_COLUMN_INDEX:
case AX_ATTR_TABLE_CELL_COLUMN_SPAN:
case AX_ATTR_TABLE_CELL_ROW_INDEX:
case AX_ATTR_TABLE_CELL_ROW_SPAN:
case AX_ATTR_SORT_DIRECTION:
case AX_ATTR_HIERARCHICAL_LEVEL:
case AX_ATTR_NAME_FROM:
case AX_ATTR_DESCRIPTION_FROM:
case AX_ATTR_CHILD_TREE_ID:
case AX_ATTR_SET_SIZE:
case AX_ATTR_POS_IN_SET:
case AX_ATTR_COLOR_VALUE:
case AX_ATTR_BACKGROUND_COLOR:
case AX_ATTR_COLOR:
case AX_ATTR_INVALID_STATE:
case AX_ATTR_TEXT_DIRECTION:
case AX_ATTR_TEXT_STYLE:
return false;
}
NOTREACHED();
return false;
}
// Return true if |attr| contains a vector of node ids that would need
// to be mapped when renumbering the ids in a combined tree.
bool IsNodeIdIntListAttribute(AXIntListAttribute attr) {
switch (attr) {
case AX_ATTR_CELL_IDS:
case AX_ATTR_CONTROLS_IDS:
case AX_ATTR_DESCRIBEDBY_IDS:
case AX_ATTR_FLOWTO_IDS:
case AX_ATTR_INDIRECT_CHILD_IDS:
case AX_ATTR_LABELLEDBY_IDS:
case AX_ATTR_UNIQUE_CELL_IDS:
return true;
// Note: all of the attributes are included here explicitly,
// rather than using "default:", so that it's a compiler error to
// add a new attribute without explicitly considering whether it's
// a node id attribute or not.
case AX_INT_LIST_ATTRIBUTE_NONE:
case AX_ATTR_LINE_BREAKS:
case AX_ATTR_CHARACTER_OFFSETS:
case AX_ATTR_WORD_STARTS:
case AX_ATTR_WORD_ENDS:
return false;
}
NOTREACHED();
return false;
}
} // namespace
AXTreeCombiner::AXTreeCombiner() {
}
AXTreeCombiner::~AXTreeCombiner() {
}
void AXTreeCombiner::AddTree(const AXTreeUpdate& tree, bool is_root) {
trees_.push_back(tree);
if (is_root) {
DCHECK_EQ(root_tree_id_, -1);
root_tree_id_ = tree.tree_data.tree_id;
}
}
bool AXTreeCombiner::Combine() {
// First create a map from tree ID to tree update.
for (const auto& tree : trees_) {
int32_t tree_id = tree.tree_data.tree_id;
if (tree_id_map_.find(tree_id) != tree_id_map_.end())
return false;
tree_id_map_[tree.tree_data.tree_id] = &tree;
}
// Make sure the root tree ID is in the map, otherwise fail.
if (tree_id_map_.find(root_tree_id_) == tree_id_map_.end())
return false;
// Process the nodes recursively, starting with the root tree.
const AXTreeUpdate* root = tree_id_map_.find(root_tree_id_)->second;
ProcessTree(root);
// Finally, handle the tree ID, taking into account which subtree might
// have focus and mapping IDs from the tree data appropriately.
combined_.has_tree_data = true;
combined_.tree_data = root->tree_data;
int32_t focused_tree_id = root->tree_data.focused_tree_id;
const AXTreeUpdate* focused_tree = root;
if (tree_id_map_.find(focused_tree_id) != tree_id_map_.end())
focused_tree = tree_id_map_[focused_tree_id];
combined_.tree_data.focus_id =
MapId(focused_tree_id, focused_tree->tree_data.focus_id);
combined_.tree_data.sel_anchor_object_id =
MapId(focused_tree_id, focused_tree->tree_data.sel_anchor_object_id);
combined_.tree_data.sel_focus_object_id =
MapId(focused_tree_id, focused_tree->tree_data.sel_focus_object_id);
combined_.tree_data.sel_anchor_offset =
focused_tree->tree_data.sel_anchor_offset;
combined_.tree_data.sel_focus_offset =
focused_tree->tree_data.sel_focus_offset;
// Debug-mode check that the resulting combined tree is valid.
AXTree tree;
DCHECK(tree.Unserialize(combined_))
<< combined_.ToString() << "\n" << tree.error();
return true;
}
int32_t AXTreeCombiner::MapId(int32_t tree_id, int32_t node_id) {
auto tree_id_node_id = std::make_pair(tree_id, node_id);
if (tree_id_node_id_map_[tree_id_node_id] == 0)
tree_id_node_id_map_[tree_id_node_id] = next_id_++;
return tree_id_node_id_map_[tree_id_node_id];
}
void AXTreeCombiner::ProcessTree(const AXTreeUpdate* tree) {
// The root of each tree may contain a transform that needs to apply
// to all of its descendants.
gfx::Transform old_transform = transform_;
if (!tree->nodes.empty() && tree->nodes[0].transform)
transform_.ConcatTransform(*tree->nodes[0].transform);
int32_t tree_id = tree->tree_data.tree_id;
for (size_t i = 0; i < tree->nodes.size(); ++i) {
AXNodeData node = tree->nodes[i];
int32_t child_tree_id = node.GetIntAttribute(AX_ATTR_CHILD_TREE_ID);
// It's not valid to have an accessibility tree with more than one
// ROOT_WEB_AREA role, so change subdocuments into just groups.
if (node.role == AX_ROLE_ROOT_WEB_AREA && tree_id != root_tree_id_)
node.role = AX_ROLE_GROUP;
// Map the node's ID.
node.id = MapId(tree_id, node.id);
// Map the node's child IDs.
for (size_t j = 0; j < node.child_ids.size(); ++j)
node.child_ids[j] = MapId(tree_id, node.child_ids[j]);
// Map other int attributes that refer to node IDs, and remove the
// AX_ATTR_CHILD_TREE_ID attribute.
for (size_t j = 0; j < node.int_attributes.size(); ++j) {
auto& attr = node.int_attributes[j];
if (IsNodeIdIntAttribute(attr.first))
attr.second = MapId(tree_id, attr.second);
if (attr.first == AX_ATTR_CHILD_TREE_ID) {
attr.first = AX_INT_ATTRIBUTE_NONE;
attr.second = 0;
}
}
// Map other int list attributes that refer to node IDs.
for (size_t j = 0; j < node.intlist_attributes.size(); ++j) {
auto& attr = node.intlist_attributes[j];
if (IsNodeIdIntListAttribute(attr.first)) {
for (size_t k = 0; k < attr.second.size(); k++)
attr.second[k] = MapId(tree_id, attr.second[k]);
}
}
// Apply the transformation to the object's bounds to put it in
// the coordinate space of the root frame.
gfx::RectF boundsf(node.location);
transform_.TransformRect(&boundsf);
node.location = gfx::Rect(boundsf.x(), boundsf.y(),
boundsf.width(), boundsf.height());
// See if this node has a child tree. As a sanity check make sure the
// child tree lists this tree as its parent tree id.
const AXTreeUpdate* child_tree = nullptr;
if (tree_id_map_.find(child_tree_id) != tree_id_map_.end()) {
child_tree = tree_id_map_.find(child_tree_id)->second;
if (child_tree->tree_data.parent_tree_id != tree_id)
child_tree = nullptr;
if (child_tree && child_tree->nodes.empty())
child_tree = nullptr;
if (child_tree) {
node.child_ids.push_back(MapId(child_tree_id,
child_tree->nodes[0].id));
}
}
// Put the rewritten AXNodeData into the output data structure.
combined_.nodes.push_back(node);
// Recurse into the child tree now, if any.
if (child_tree)
ProcessTree(child_tree);
}
// Reset the transform.
transform_ = old_transform;
}
} // namespace ui
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