cache system add lonely functionnality

lib/Ray/sources/Utils/Cache.hpp

@@ -10,6 +10,9 @@
 #include <unordered_map>
 #include <functional>
 #include <raylib.h>
+#include <vector>
+#include <algorithm>
+#include <string>
 
 namespace RAY {
 	//! @brief A templated class used to cache ressources, indexed with a string
@@ -31,16 +34,26 @@ namespace RAY {
 			Cache &operator=(const Cache &) = default;
 
 			//! @param path path of the file
+			//! @param lonely: should be set to true if the loaded data must be held by no other active entites
 			//! @return a newly loaded ressource if it hasn't be previously loaded, or one from cache            
-			std::shared_ptr<T>fetch(const std::string &path)
+			std::shared_ptr<T>fetch(const std::string &path, bool lonely = false)
 			{
-				if (this->_cache.find(path) == this->_cache.end())
-					this->_cache.emplace(path, std::shared_ptr<T>(
-					new T(this->_dataLoader(path.c_str())), [this](T *p) {
-				   		this->_dataUnloader(*p);
-				   		delete p;
-					}));
-				return _cache[path];
+				if (!this->_cache.contains(path))
+					this->_cache.emplace(path, std::vector<std::shared_ptr<T>>());
+				std::vector<std::shared_ptr<T>> &matchingDataVector = this->_cache.at(path);
+
+				for (std::shared_ptr<T> &i: matchingDataVector) {
+					if (!lonely)
+						return i;
+					if (lonely && i.use_count() == 1)
+						return i;
+				}
+				matchingDataVector.emplace_back(std::shared_ptr<T>(
+				new T(this->_dataLoader(path.c_str())), [this](T *p) {
+					this->_dataUnloader(*p);
+					delete p;
+				}));
+				return matchingDataVector.back();
 			};
 		private:
 			//! @brief function to call to load data
@@ -50,7 +63,7 @@ namespace RAY {
 			std::function<void(T)> _dataUnloader;
 
 			//! @brief map storing shared ptr of caches
-			std::unordered_map<std::string, std::shared_ptr<T>> _cache;
+			std::unordered_map<std::string, std::vector<std::shared_ptr<T>>> _cache;
 	};
 
 	template<>