ui/accessibility/test_ax_node_helper.cc

// Copyright 2020 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/test_ax_node_helper.h"

#include <map>
#include <utility>

#include "base/strings/utf_string_conversions.h"
#include "ui/accessibility/ax_action_data.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/geometry/rect_conversions.h"

namespace ui {

namespace {

// A global map from AXNodes to TestAXNodeHelpers.
std::map<AXNodeID, TestAXNodeHelper*> g_node_id_to_helper_map;

// A simple implementation of AXTreeObserver to catch when AXNodes are
// deleted so we can delete their helpers.
class TestAXTreeObserver : public AXTreeObserver {
 private:
  void OnNodeDeleted(AXTree* tree, AXNodeID node_id) override {
    const auto iter = g_node_id_to_helper_map.find(node_id);
    if (iter != g_node_id_to_helper_map.end()) {
      TestAXNodeHelper* helper = iter->second;
      delete helper;
      g_node_id_to_helper_map.erase(node_id);
    }
  }
};

TestAXTreeObserver g_ax_tree_observer;

}  // namespace

// static
TestAXNodeHelper* TestAXNodeHelper::GetOrCreate(AXTree* tree, AXNode* node) {
  if (!tree || !node)
    return nullptr;

  if (!tree->HasObserver(&g_ax_tree_observer))
    tree->AddObserver(&g_ax_tree_observer);
  auto iter = g_node_id_to_helper_map.find(node->id());
  if (iter != g_node_id_to_helper_map.end())
    return iter->second;
  TestAXNodeHelper* helper = new TestAXNodeHelper(tree, node);
  g_node_id_to_helper_map[node->id()] = helper;
  return helper;
}

TestAXNodeHelper::TestAXNodeHelper(AXTree* tree, AXNode* node)
    : tree_(tree), node_(node) {}

TestAXNodeHelper::~TestAXNodeHelper() = default;

gfx::Rect TestAXNodeHelper::GetBoundsRect(
    const AXCoordinateSystem coordinate_system,
    const AXClippingBehavior clipping_behavior,
    AXOffscreenResult* offscreen_result) const {
  switch (coordinate_system) {
    case AXCoordinateSystem::kScreenPhysicalPixels:
      // For unit testing purposes, assume a device scale factor of 1 and fall
      // through.
    case AXCoordinateSystem::kScreenDIPs: {
      // We could optionally add clipping here if ever needed.
      gfx::RectF bounds = GetLocation();

      // For test behavior only, for bounds that are offscreen we currently do
      // not apply clipping to the bounds but we still return the offscreen
      // status.
      if (offscreen_result) {
        *offscreen_result = DetermineOffscreenResult(bounds);
      }

      return gfx::ToEnclosingRect(bounds);
    }
    case AXCoordinateSystem::kRootFrame:
    case AXCoordinateSystem::kFrame:
      NOTIMPLEMENTED();
      return gfx::Rect();
  }
}

gfx::Rect TestAXNodeHelper::GetInnerTextRangeBoundsRect(
    const int start_offset,
    const int end_offset,
    const AXCoordinateSystem coordinate_system,
    const AXClippingBehavior clipping_behavior,
    AXOffscreenResult* offscreen_result) const {
  switch (coordinate_system) {
    case AXCoordinateSystem::kScreenPhysicalPixels:
    // For unit testing purposes, assume a device scale factor of 1 and fall
    // through.
    case AXCoordinateSystem::kScreenDIPs: {
      gfx::RectF bounds = GetLocation();
      // This implementation currently only deals with text node that has role
      // kInlineTextBox and kStaticText.
      // For test purposes, assume node with kStaticText always has a single
      // child with role kInlineTextBox.
      if (node_->GetRole() == ax::mojom::Role::kInlineTextBox) {
        bounds = GetInlineTextRect(start_offset, end_offset);
      } else if (node_->GetRole() == ax::mojom::Role::kStaticText &&
                 InternalChildCount() > 0) {
        TestAXNodeHelper* child = InternalGetChild(0);
        if (child != nullptr &&
            child->node_->GetRole() == ax::mojom::Role::kInlineTextBox) {
          bounds = child->GetInlineTextRect(start_offset, end_offset);
        }
      }

      // For test behavior only, for bounds that are offscreen we currently do
      // not apply clipping to the bounds but we still return the offscreen
      // status.
      if (offscreen_result) {
        *offscreen_result = DetermineOffscreenResult(bounds);
      }

      return gfx::ToEnclosingRect(bounds);
    }
    case AXCoordinateSystem::kRootFrame:
    case AXCoordinateSystem::kFrame:
      NOTIMPLEMENTED();
      return gfx::Rect();
  }
}

const AXNodeData& TestAXNodeHelper::GetData() const {
  return node_->data();
}

gfx::RectF TestAXNodeHelper::GetLocation() const {
  return GetData().relative_bounds.bounds;
}

int TestAXNodeHelper::InternalChildCount() const {
  return static_cast<int>(node_->GetUnignoredChildCount());
}

TestAXNodeHelper* TestAXNodeHelper::InternalGetChild(int index) const {
  CHECK_GE(index, 0);
  CHECK_LT(index, InternalChildCount());
  return GetOrCreate(
      tree_, node_->GetUnignoredChildAtIndex(static_cast<size_t>(index)));
}

gfx::RectF TestAXNodeHelper::GetInlineTextRect(const int start_offset,
                                               const int end_offset) const {
  DCHECK(start_offset >= 0 && end_offset >= 0 && start_offset <= end_offset);
  const std::vector<int32_t>& character_offsets = node_->GetIntListAttribute(
      ax::mojom::IntListAttribute::kCharacterOffsets);
  gfx::RectF location = GetLocation();
  gfx::RectF bounds;

  switch (static_cast<ax::mojom::WritingDirection>(
      node_->GetIntAttribute(ax::mojom::IntAttribute::kTextDirection))) {
    // Currently only kNone and kLtr are supported text direction.
    case ax::mojom::WritingDirection::kNone:
    case ax::mojom::WritingDirection::kLtr: {
      int start_pixel_offset =
          start_offset > 0 ? character_offsets[start_offset - 1] : location.x();
      int end_pixel_offset =
          end_offset > 0 ? character_offsets[end_offset - 1] : location.x();
      bounds =
          gfx::RectF(start_pixel_offset, location.y(),
                     end_pixel_offset - start_pixel_offset, location.height());
      break;
    }
    default:
      NOTIMPLEMENTED();
  }
  return bounds;
}

bool TestAXNodeHelper::Intersects(gfx::RectF rect1, gfx::RectF rect2) const {
  // The logic below is based on gfx::RectF::Intersects.
  // gfx::RectF::Intersects returns false if either of the two rects is empty.
  // This function is used in tests to determine offscreen status. We want to
  // include empty rect in our logic since the bounding box of a degenerate text
  // range is initially empty (width=0), and we do not want to mark it as
  // offscreen.
  return rect1.x() < rect2.right() && rect1.right() > rect2.x() &&
         rect1.y() < rect2.bottom() && rect1.bottom() > rect2.y();
}

AXOffscreenResult TestAXNodeHelper::DetermineOffscreenResult(
    gfx::RectF bounds) const {
  if (!tree_ || !tree_->root())
    return AXOffscreenResult::kOnscreen;

  const AXNodeData& root_web_area_node_data = tree_->root()->data();
  gfx::RectF root_web_area_bounds =
      root_web_area_node_data.relative_bounds.bounds;

  // For testing, we only look at the current node's bound relative to the root
  // web area bounds to determine offscreen status. We currently do not look at
  // the bounds of the immediate parent of the node for determining offscreen
  // status.
  // We only determine offscreen result if the root web area bounds is actually
  // set in the test, and we mark a node as offscreen only when |bounds| is
  // completely outside of |root_web_area_bounds| (i.e. not contained by
  // |root_web_area_bounds|). We default the offscreen result of every other
  // situation to AXOffscreenResult::kOnscreen.
  if (!root_web_area_bounds.IsEmpty() &&
      !Intersects(bounds, root_web_area_bounds)) {
    return AXOffscreenResult::kOffscreen;
  }

  return AXOffscreenResult::kOnscreen;
}
}  // namespace ui