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source/opengl/resource_management/resource_manager.ipp

@@ -0,0 +1,139 @@
+#ifndef INCLUDE_RESOURCE_MANAGER_IMPLEMENTATION
+#	error Never include this file directly include 'resource_manager.hpp'
+#endif
+
+#include <ranges>
+
+
+template<typename StoreID, typename MetaData>
+bool zgl::resource_manager<StoreID, MetaData>::has_resource(StoreID store_id)
+{
+	std::shared_lock lock(m_lock);
+	return m_resource_lookup.contains(store_id);
+}
+
+template<typename StoreID, typename MetaData>
+void zgl::resource_manager<StoreID, MetaData>::add_resource(StoreID store_id, gl_id_type gl_id, MetaData meta)
+{
+	std::unique_lock lock(m_lock);
+	m_resource_lookup.emplace(store_id, { gl_id, std::move(meta) });
+	m_reference_counters.emplace(gl_id, 1);
+}
+
+
+template<typename StoreID, typename MetaData>
+std::optional<std::pair<zgl::resource_handle, MetaData>> zgl::resource_manager<StoreID, MetaData>::get_resource(
+	StoreID store_id
+) {
+	std::unique_lock lock(m_lock);
+
+	const auto resource_it = m_resource_lookup.find(store_id);
+	if (resource_it == m_resource_lookup.end())
+	{
+		return std::nullopt;
+	}
+
+	const auto gl_id = resource_it.first;
+
+	auto [ counter_it, inserted ] = m_reference_counters.try_emplace(gl_id, 0);
+
+	++counter_it->second;
+
+	return std::pair{ resource_handle(gl_id, this), resource_it->second };
+}
+
+template<typename StoreID, typename MetaData>
+void zgl::resource_manager<StoreID, MetaData>::collect_garbage()
+{
+	std::unique_lock lock(m_lock);
+
+	for (auto& counter :  m_reference_counters | std::ranges::views::values)
+	{
+		if (counter & unused_resource_flag)
+		{
+			const auto value = counter & ~unused_resource_flag;
+			counter = (value + 1) | unused_resource_flag;
+		}
+	}
+
+	std::erase_if(
+		m_reference_counters,
+		[&](const auto& entry)
+		{
+			auto& counter = entry.second;
+
+			const auto value = counter & ~unused_resource_flag;
+
+			if (value == counter) // Still in use
+			{
+				return false;
+			}
+
+			if (value < max_unused_collection_cycle_count)
+			{
+				counter = (value + 1) | unused_resource_flag;
+				return false;
+			}
+
+			m_unused_handles.emplace(entry.first);
+
+			return true;
+		}
+	);
+
+	std::erase_if(
+		m_resource_lookup,
+		[&](const auto& entry)
+		{
+			return m_unused_handles.contains(entry.second);
+		}
+	);
+}
+
+
+template<typename StoreID, typename MetaData>
+void zgl::resource_manager<StoreID, MetaData>::add_reference(const gl_id_type id)
+{
+	std::unique_lock lock(m_lock);
+	auto [it, inserted] = m_reference_counters.try_emplace(id, 0);
+	++it->second;
+}
+
+template<typename StoreID, typename MetaData>
+void zgl::resource_manager<StoreID, MetaData>::remove_reference(const gl_id_type id)
+{
+	std::unique_lock lock(m_lock);
+	if (const auto it = m_reference_counters.find(id); it != m_reference_counters.end())
+	{
+		if (it->second == 1)
+		{
+			it->second = unused_resource_flag;
+		}
+	}
+}
+
+template<typename StoreID, typename MetaData>
+typename zgl::resource_manager<StoreID, MetaData>::size_type zgl::resource_manager<StoreID, MetaData>::count_garbage()
+{
+	std::shared_lock lock(m_lock);
+	return m_unused_handles.size();
+}
+
+template<typename StoreID, typename MetaData>
+void zgl::resource_manager<StoreID, MetaData>::extract_garbage(
+	std::vector<gl_id_type>& dst
+) {
+	{
+		std::shared_lock lock(m_lock);
+		dst.reserve(m_unused_handles.size());
+	}
+	{
+		std::unique_lock lock(m_lock);
+
+		dst.resize(m_unused_handles.size());
+
+		std::ranges::copy(m_unused_handles, dst.begin());
+
+		m_unused_handles.clear();
+	}
+}