tools/accessibility/inspect/ax_tree_server.cc

// Copyright 2017 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 "tools/accessibility/inspect/ax_tree_server.h"

#include <iostream>
#include <string>

#include "base/at_exit.h"
#include "base/bind.h"
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/path_service.h"
#include "base/run_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_restrictions.h"
#include "base/values.h"
#include "content/public/browser/ax_inspect_factory.h"
#include "ui/accessibility/platform/inspect/ax_inspect_scenario.h"

using ui::AXTreeFormatter;
using ui::AXTreeSelector;

namespace content {

AXTreeServer::AXTreeServer(const AXTreeSelector& selector,
                           const base::FilePath& filters_path) {
  std::unique_ptr<AXTreeFormatter> formatter(
      AXInspectFactory::CreatePlatformFormatter());

  // Get filters from optional filters file.
  absl::optional<ui::AXInspectScenario> scenario =
      GetInspectScenario(filters_path);
  if (!scenario) {
    LOG(ERROR) << "Failed to parse filter file";
    return;
  }

  // Use optional filters with the default filter set
  formatter->SetPropertyFilters(scenario->property_filters,
                                AXTreeFormatter::kFiltersDefaultSet);

  // Get accessibility tree as a nested dictionary.
  base::Value dict = formatter->BuildTreeForSelector(selector);
  if (dict.DictEmpty()) {
    LOG(ERROR) << "Failed to get accessibility tree";
    return;
  }

  // Write to console.
  printf("%s", formatter->FormatTree(dict).c_str());
}

absl::optional<ui::AXInspectScenario> AXTreeServer::GetInspectScenario(
    const base::FilePath& filters_path) {
  // Return with the default filter scenario if no file is provided
  if (filters_path.empty()) {
    return ui::AXInspectScenario::From("@", std::vector<std::string>());
  }

  absl::optional<ui::AXInspectScenario> scenario =
      ui::AXInspectScenario::From("@", filters_path);
  if (!scenario) {
    LOG(ERROR) << "Failed to open filters file " << filters_path
               << ". Note: path traversal components ('..') are not allowed "
                  "for security reasons";
    return absl::nullopt;
  }
  return scenario;
}

}  // namespace content