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 "androidfw/IDiagnostics.h"
#include "xml/XmlDom.h"

namespace aapt {
namespace xml {

enum class XmlActionExecutorPolicy {
  // Actions are 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.
  // Note: namespaced elements are always ignored.
  kAllowList,

  // The actions defined should match and run. if an element is found that does not match an
  // action, a warning is printed.
  // Note: namespaced elements are always ignored.
  kAllowListWarning,
};

// 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 ActionFuncWithPolicyAndDiag =
      std::function<bool(Element*, XmlActionExecutorPolicy, android::SourcePathDiagnostics*)>;
  using ActionFuncWithDiag = std::function<bool(Element*, android::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);
  void Action(ActionFuncWithPolicyAndDiag);

 private:
  friend class XmlActionExecutor;

  bool Execute(XmlActionExecutorPolicy policy, std::vector<::android::StringPiece>* bread_crumb,
               android::SourcePathDiagnostics* diag, Element* el) const;

  std::map<std::string, XmlNodeAction> map_;
  std::vector<ActionFuncWithPolicyAndDiag> 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, android::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 */