tools/aapt2/xml/XmlActionExecutor.h

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef AAPT_XML_XMLPATTERN_H
#define AAPT_XML_XMLPATTERN_H

#include <functional>
#include <map>
#include <string>
#include <vector>

#include "android-base/macros.h"

#include "Diagnostics.h"
#include "xml/XmlDom.h"

namespace aapt {
namespace xml {

enum class XmlActionExecutorPolicy {
  /**
   * Actions on run if elements are matched, errors occur only when actions
   * return false.
   */
  kNone,

  /**
   * The actions defined must match and run. If an element is found that does
   * not match
   * an action, an error occurs.
   */
  kWhitelist,
};

/**
 * Contains the actions to perform at this XML node. This is a recursive data
 * structure that
 * holds XmlNodeActions for child XML nodes.
 */
class XmlNodeAction {
 public:
  using ActionFuncWithDiag =
      std::function<bool(Element*, SourcePathDiagnostics*)>;
  using ActionFunc = std::function<bool(Element*)>;

  /**
   * Find or create a child XmlNodeAction that will be performed for the child
   * element
   * with the name `name`.
   */
  XmlNodeAction& operator[](const std::string& name) { return map_[name]; }

  /**
   * Add an action to be performed at this XmlNodeAction.
   */
  void Action(ActionFunc f);
  void Action(ActionFuncWithDiag);

 private:
  friend class XmlActionExecutor;

  bool Execute(XmlActionExecutorPolicy policy, SourcePathDiagnostics* diag,
               Element* el) const;

  std::map<std::string, XmlNodeAction> map_;
  std::vector<ActionFuncWithDiag> actions_;
};

/**
 * Allows the definition of actions to execute at specific XML elements defined
 * by their
 * hierarchy.
 */
class XmlActionExecutor {
 public:
  XmlActionExecutor() = default;

  /**
   * Find or create a root XmlNodeAction that will be performed for the root XML
   * element with the name `name`.
   */
  XmlNodeAction& operator[](const std::string& name) { return map_[name]; }

  /**
   * Execute the defined actions for this XmlResource.
   * Returns true if all actions return true, otherwise returns false.
   */
  bool Execute(XmlActionExecutorPolicy policy, IDiagnostics* diag,
               XmlResource* doc) const;

 private:
  std::map<std::string, XmlNodeAction> map_;

  DISALLOW_COPY_AND_ASSIGN(XmlActionExecutor);
};

}  // namespace xml
}  // namespace aapt

#endif /* AAPT_XML_XMLPATTERN_H */