Source/cmVariableWatch.h

   1 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
   2    file Copyright.txt or https://cmake.org/licensing for details.  */
   3 #pragma once
   4
   5 #include "cmConfigure.h" // IWYU pragma: keep
   6
   7 #include <map>
   8 #include <memory>
   9 #include <string>
  10 #include <vector>
  11
  12 class cmMakefile;
  13
  14 /** \class cmVariableWatch
  15  * \brief Helper class for watching of variable accesses.
  16  *
  17  * Calls function when variable is accessed
  18  */
  19 class cmVariableWatch
  20 {
  21 public:
  22   using WatchMethod = void (*)(const std::string&, int, void*, const char*,
  23                                const cmMakefile*);
  24   using DeleteData = void (*)(void*);
  25
  26   cmVariableWatch();
  27   ~cmVariableWatch();
  28
  29   /**
  30    * Add watch to the variable
  31    */
  32   bool AddWatch(const std::string& variable, WatchMethod method,
  33                 void* client_data = nullptr, DeleteData delete_data = nullptr);
  34   void RemoveWatch(const std::string& variable, WatchMethod method,
  35                    void* client_data = nullptr);
  36
  37   /**
  38    * This method is called when variable is accessed
  39    */
  40   bool VariableAccessed(const std::string& variable, int access_type,
  41                         const char* newValue, const cmMakefile* mf) const;
  42
  43   /**
  44    * Different access types.
  45    */
  46   enum
  47   {
  48     VARIABLE_READ_ACCESS,
  49     UNKNOWN_VARIABLE_READ_ACCESS,
  50     UNKNOWN_VARIABLE_DEFINED_ACCESS,
  51     VARIABLE_MODIFIED_ACCESS,
  52     VARIABLE_REMOVED_ACCESS,
  53     NO_ACCESS
  54   };
  55
  56   /**
  57    * Return the access as string
  58    */
  59   static const std::string& GetAccessAsString(int access_type);
  60
  61 protected:
  62   struct Pair
  63   {
  64     WatchMethod Method = nullptr;
  65     void* ClientData = nullptr;
  66     DeleteData DeleteDataCall = nullptr;
  67     ~Pair()
  68     {
  69       if (this->DeleteDataCall && this->ClientData) {
  70         this->DeleteDataCall(this->ClientData);
  71       }
  72     }
  73     Pair() = default;
  74     Pair(const Pair&) = delete;
  75     Pair& operator=(const Pair&) = delete;
  76   };
  77
  78   using VectorOfPairs = std::vector<std::shared_ptr<Pair>>;
  79   using StringToVectorOfPairs = std::map<std::string, VectorOfPairs>;
  80
  81   StringToVectorOfPairs WatchMap;
  82 };