refactor(renderer): simplify buffer and texture cache ownership

src/common/slotVector.h

@@ -0,0 +1,132 @@
+#ifndef EMULATOR_SRC_COMMON_SLOTVECTOR_H_
+#define EMULATOR_SRC_COMMON_SLOTVECTOR_H_
+
+#include "common/assert.h"
+#include "common/abi.h"
+
+#include <compare>
+#include <cstdint>
+#include <deque>
+#include <functional>
+#include <limits>
+#include <optional>
+#include <utility>
+#include <vector>
+
+namespace Common {
+
+struct SlotId {
+	static constexpr uint32_t INVALID_INDEX = std::numeric_limits<uint32_t>::max();
+
+	constexpr SlotId() noexcept = default;
+	constexpr SlotId(uint32_t value) noexcept: index(value), generation(1) {}
+	constexpr SlotId(uint32_t value, uint32_t slot_generation) noexcept
+	    : index(value), generation(slot_generation) {}
+
+	[[nodiscard]] constexpr explicit operator bool() const noexcept { return index != INVALID_INDEX; }
+	constexpr auto operator<=>(const SlotId&) const noexcept = default;
+
+	uint32_t index = INVALID_INDEX;
+	uint32_t generation = 0;
+};
+
+// Stable-address slot storage for cache resources that are intentionally non-movable.
+template <typename T>
+class SlotVector {
+public:
+	SlotVector() = default;
+	KYTY_CLASS_NO_COPY(SlotVector);
+
+	[[nodiscard]] T& operator[](SlotId id) noexcept {
+		EXIT_IF(!is_allocated(id));
+		return *m_values[id.index].value;
+	}
+
+	[[nodiscard]] const T& operator[](SlotId id) const noexcept {
+		EXIT_IF(!is_allocated(id));
+		return *m_values[id.index].value;
+	}
+
+	[[nodiscard]] T* try_get(SlotId id) noexcept {
+		return is_allocated(id) ? &*m_values[id.index].value : nullptr;
+	}
+
+	[[nodiscard]] const T* try_get(SlotId id) const noexcept {
+		return is_allocated(id) ? &*m_values[id.index].value : nullptr;
+	}
+
+	[[nodiscard]] bool is_allocated(SlotId id) const noexcept {
+		return id && id.index < m_values.size() &&
+		       m_values[id.index].generation == id.generation && m_values[id.index].value.has_value();
+	}
+
+	template <typename... Args>
+	[[nodiscard]] SlotId insert(Args&&... args) {
+		uint32_t index = 0;
+		if (m_free_list.empty()) {
+			index = static_cast<uint32_t>(m_values.size());
+			m_values.emplace_back();
+			m_values.back().value.emplace(std::forward<Args>(args)...);
+		} else {
+			index = m_free_list.back();
+			m_free_list.pop_back();
+			EXIT_IF(m_values[index].value.has_value());
+			m_values[index].value.emplace(std::forward<Args>(args)...);
+		}
+		++m_size;
+		return SlotId {index, m_values[index].generation};
+	}
+
+	void erase(SlotId id) noexcept {
+		EXIT_IF(!is_allocated(id));
+		auto& slot = m_values[id.index];
+		slot.value.reset();
+		if (++slot.generation == 0) {
+			slot.generation = 1;
+		}
+		m_free_list.push_back(id.index);
+		--m_size;
+	}
+
+	[[nodiscard]] size_t size() const noexcept { return m_size; }
+	[[nodiscard]] size_t capacity() const noexcept { return m_values.size(); }
+
+	template <typename F>
+	void ForEach(F&& fn) {
+		for (uint32_t index = 0; index < m_values.size(); ++index) {
+			if (m_values[index].value) {
+				fn(SlotId {index, m_values[index].generation}, *m_values[index].value);
+			}
+		}
+	}
+
+	template <typename F>
+	void ForEach(F&& fn) const {
+		for (uint32_t index = 0; index < m_values.size(); ++index) {
+			if (m_values[index].value) {
+				fn(SlotId {index, m_values[index].generation}, *m_values[index].value);
+			}
+		}
+	}
+
+private:
+	struct Slot {
+		std::optional<T> value;
+		uint32_t         generation = 1;
+	};
+
+	std::deque<Slot>             m_values;
+	std::vector<uint32_t>        m_free_list;
+	size_t                       m_size = 0;
+};
+
+} // namespace Common
+
+template <>
+struct std::hash<Common::SlotId> {
+	[[nodiscard]] size_t operator()(Common::SlotId id) const noexcept {
+		return std::hash<uint64_t> {}((static_cast<uint64_t>(id.generation) << 32u) | id.index);
+	}
+};
+
+#endif // EMULATOR_SRC_COMMON_SLOTVECTOR_H_