--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/foosdk/sdk/foobar2000/helpers/metadb_io_callback_v2_data.h	Mon Jan 05 02:15:46 2026 -0500
@@ -0,0 +1,50 @@
+#pragma once
+
+#pragma once
+#include <mutex>
+#include <vector>
+#include <SDK/metadb_callbacks.h>
+
+class metadb_io_callback_v2_data_impl : public metadb_io_callback_v2_data {
+	metadb_handle_list_cref m_items;
+	pfc::array_t< metadb_v2_rec_t> m_data;
+	std::once_flag m_once;
+public:
+	metadb_io_callback_v2_data_impl(metadb_handle_list_cref items) : m_items(items) {}
+	metadb_v2_rec_t get(size_t idxInList) override {
+		// Late init, don't hammer metadb if nobody cares
+		// Maybe this should be offthread somehow?? Kick off early, stall till done once asked?
+		std::call_once(m_once, [&] { m_data = metadb_v2::get()->queryMultiSimple(m_items); });
+		PFC_ASSERT(m_data.size() == m_items.get_size());
+		PFC_ASSERT(idxInList < m_data.size());
+		return m_data[idxInList];
+	}
+};
+
+class metadb_io_callback_v2_data_wrap : public metadb_io_callback_v2_data {
+public:
+	metadb_io_callback_v2_data_wrap(metadb_io_callback_v2_data& chain) : m_chain(chain) {}
+	metadb_io_callback_v2_data& m_chain;
+	std::vector<size_t> m_mapping;
+
+	metadb_v2_rec_t get(size_t idxInList) override {
+		PFC_ASSERT(idxInList < m_mapping.size());
+		return m_chain[m_mapping[idxInList]];
+	}
+};
+
+class metadb_io_callback_v2_data_mirror : public metadb_io_callback_v2_data {
+public:
+	metadb_v2_rec_t get(size_t idxInList) override {return m_data[idxInList];}
+
+	metadb_io_callback_v2_data_mirror() {}
+	metadb_io_callback_v2_data_mirror(metadb_io_callback_v2_data& source, size_t size) {
+		init(source, size);
+	}
+	void init(metadb_io_callback_v2_data& source, size_t size) {
+		m_data.set_size_discard(size);
+		for (size_t w = 0; w < size; ++w) m_data[w] = source[w];
+	}
+private:
+	pfc::array_t< metadb_v2_rec_t> m_data;
+};
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