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  1. #include <functional>
  2. #include <vector>
  3. #include <memory>
  4. #include <mutex>
  5.  
  6. #include <iostream>
  7. using std::cout;
  8. using std::endl;
  9.  
  10. template<typename T>
  11. class ResourceManager{
  12. public:
  13. 	using Actions = struct{
  14. 		using LoadFunc = std::function<T*(const std::string &)>;
  15. 		using UnloadFunc = std::function<void(T *)>;
  16. 		LoadFunc load;
  17. 		UnloadFunc unload;
  18. 	};
  19. 	using ResourcePtr = std::unique_ptr<T, typename Actions::UnloadFunc>;
  20. 	struct MutexWrapper{
  21. 	    std::mutex m;
  22. 	    MutexWrapper() {}
  23. 	    MutexWrapper(MutexWrapper const&) {}
  24. 	    MutexWrapper& operator=(MutexWrapper const&) { return *this; }
  25. 	    inline std::mutex &get(){ return m; }
  26. 	};
  27. 	using Key = size_t;
  28. public:
  29. 	ResourceManager(Actions actions):
  30. 		_actions(actions){}
  31. 	ResourceManager(const ResourceManager &rhs) = delete;
  32. public:
  33. 	Key load(const std::string &path){
  34. 		auto resource = _actions.load(path);
  35. 		return load(resource);
  36. 	}
  37.  
  38. 	Key load(T *resource){
  39. 		std::lock_guard<std::mutex> guard(_mutex);
  40. 		auto resourcePtr = ResourcePtr(resource, _actions.unload);
  41. 		_resources.push_back(std::move(resourcePtr));
  42. 		_mutexes.push_back(MutexWrapper());
  43. 		return _resources.size()-1;
  44. 	}
  45.  
  46. 	void unload(Key key){
  47. 		std::lock_guard<std::mutex> guard(_mutex);
  48. 		_resources.erase(_resources.begin()+key);
  49. 		_mutexes.erase(_mutexes.begin()+key);
  50. 	}
  51.  
  52. 	void operate(Key key, std::function<void(T&)> operation){
  53. 		std::lock_guard<std::mutex> guard(_mutexes.at(key).get());
  54. 		operation(*_resources.at(key));
  55. 	}
  56.  
  57. 	void operate(Key key, std::function<void(const T&)> operation) const{
  58. 		std::lock_guard<std::mutex> guard(_mutexes.at(key).get());
  59. 		operation(*_resources.at(key));
  60. 	}
  61. private:
  62. 	Actions	_actions;
  63. 	std::vector<ResourcePtr> _resources;
  64. 	std::vector<MutexWrapper> _mutexes;
  65. 	std::mutex _mutex;
  66. };
  67.  
  68. int main() {
  69. 	ResourceManager<int> rm{{
  70. 		[](const std::string &){return new int;},
  71. 		[](int *arg){ delete arg; }
  72. 	}};
  73.  
  74. 	auto id = rm.load(new int(5));
  75. 	rm.operate(id, [](int&arg){ cout << "Hello world! " << arg << endl; });
  76. 	return 0;
  77. }
Success #stdin #stdout 0s 3476KB
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stdin
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Standard input is empty
stdout
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Hello world! 5
https://ideone.com/f2TRLR
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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