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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef AAPT_XML_XMLPATTERN_H
     18 #define AAPT_XML_XMLPATTERN_H
     19 
     20 #include <functional>
     21 #include <map>
     22 #include <string>
     23 #include <vector>
     24 
     25 #include "android-base/macros.h"
     26 
     27 #include "Diagnostics.h"
     28 #include "xml/XmlDom.h"
     29 
     30 namespace aapt {
     31 namespace xml {
     32 
     33 enum class XmlActionExecutorPolicy {
     34   // Actions are run if elements are matched, errors occur only when actions return false.
     35   kNone,
     36 
     37   // The actions defined must match and run. If an element is found that does
     38   // not match an action, an error occurs.
     39   // Note: namespaced elements are always ignored.
     40   kWhitelist,
     41 };
     42 
     43 /**
     44  * Contains the actions to perform at this XML node. This is a recursive data
     45  * structure that
     46  * holds XmlNodeActions for child XML nodes.
     47  */
     48 class XmlNodeAction {
     49  public:
     50   using ActionFuncWithDiag = std::function<bool(Element*, SourcePathDiagnostics*)>;
     51   using ActionFunc = std::function<bool(Element*)>;
     52 
     53   /**
     54    * Find or create a child XmlNodeAction that will be performed for the child
     55    * element with the name `name`.
     56    */
     57   XmlNodeAction& operator[](const std::string& name) { return map_[name]; }
     58 
     59   /**
     60    * Add an action to be performed at this XmlNodeAction.
     61    */
     62   void Action(ActionFunc f);
     63   void Action(ActionFuncWithDiag);
     64 
     65  private:
     66   friend class XmlActionExecutor;
     67 
     68   bool Execute(XmlActionExecutorPolicy policy, SourcePathDiagnostics* diag, Element* el) const;
     69 
     70   std::map<std::string, XmlNodeAction> map_;
     71   std::vector<ActionFuncWithDiag> actions_;
     72 };
     73 
     74 /**
     75  * Allows the definition of actions to execute at specific XML elements defined
     76  * by their
     77  * hierarchy.
     78  */
     79 class XmlActionExecutor {
     80  public:
     81   XmlActionExecutor() = default;
     82 
     83   /**
     84    * Find or create a root XmlNodeAction that will be performed for the root XML
     85    * element with the name `name`.
     86    */
     87   XmlNodeAction& operator[](const std::string& name) { return map_[name]; }
     88 
     89   /**
     90    * Execute the defined actions for this XmlResource.
     91    * Returns true if all actions return true, otherwise returns false.
     92    */
     93   bool Execute(XmlActionExecutorPolicy policy, IDiagnostics* diag, XmlResource* doc) const;
     94 
     95  private:
     96   std::map<std::string, XmlNodeAction> map_;
     97 
     98   DISALLOW_COPY_AND_ASSIGN(XmlActionExecutor);
     99 };
    100 
    101 }  // namespace xml
    102 }  // namespace aapt
    103 
    104 #endif /* AAPT_XML_XMLPATTERN_H */
    105