include/library/globalwrap.hpp

   1 #ifndef _library__globalwrap__hpp__included__
   2 #define _library__globalwrap__hpp__included__
   3
   4 #include <iostream>
   5
   6 /**
   7  * Wrapper for glboal/module-local objects accessable in global ctor context.
   8  */
   9 template<class T>
  10 class globalwrap
  11 {
  12 public:
  13 /**
  14  * Ctor, forces the object to be constructed (to avoid races).
  15  */
  16         globalwrap() throw(std::bad_alloc)
  17         {
  18                 (*this)();
  19         }
  20 /**
  21  * Get the wrapped object.
  22  *
  23  * returns: The wrapped object.
  24  * throws std::bad_alloc: Not enough memory.
  25  */
  26         T& operator()() throw(std::bad_alloc)
  27         {
  28                 if(!storage) {
  29                         if(!state)      //State initializes to 0.
  30                                 state = 1;
  31                         else if(state == 1)
  32                                 std::cerr << "Warning: Recursive use of globalwrap<T>." << std::endl;
  33                         storage = new T();
  34                         state = 2;
  35                 }
  36                 return *storage;
  37         }
  38 private:
  39         T* storage;
  40         unsigned state;
  41 };
  42
  43 #endif