--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/foosdk/sdk/foobar2000/SDK/metadb_callbacks.h	Mon Jan 05 02:15:46 2026 -0500
@@ -0,0 +1,105 @@
+#pragma once
+#include "callback_merit.h"
+
+//! Callback service receiving notifications about metadb contents changes.
+class NOVTABLE metadb_io_callback : public service_base {
+public:
+	//! Called when metadb contents change. (Or, one of display hook component requests display update). \n
+	//! Main thread only.
+	//! @param p_items_sorted List of items that have been updated. The list is always sorted by pointer value, to allow fast bsearch to test whether specific item has changed.
+	//! @param p_fromhook Set to true when actual file contents haven't changed but one of metadb_display_field_provider implementations requested an update so output of metadb_handle::format_title() etc has changed.
+	virtual void on_changed_sorted(metadb_handle_list_cref p_items_sorted, bool p_fromhook) = 0;
+
+	FB2K_MAKE_SERVICE_INTERFACE_ENTRYPOINT(metadb_io_callback);
+};
+
+//! Dynamically-registered version of metadb_io_callback. See metadb_io_callback for documentation, register instances using metadb_io_v3::register_callback(). It's recommended that you use the metadb_io_callback_dynamic_impl_base helper class to manage registration/unregistration.
+class NOVTABLE metadb_io_callback_dynamic {
+public:
+	//! See metadb_io_callback::on_changed_sorted()
+	virtual void on_changed_sorted(metadb_handle_list_cref p_items_sorted, bool p_fromhook) = 0;
+
+	void register_callback(); void unregister_callback();
+
+};
+
+//! metadb_io_callback_dynamic implementation helper.
+class metadb_io_callback_dynamic_impl_base : public metadb_io_callback_dynamic {
+public:
+	void on_changed_sorted(metadb_handle_list_cref p_items_sorted, bool p_fromhook) override { (void)p_items_sorted; (void)p_fromhook; }
+
+	metadb_io_callback_dynamic_impl_base();
+	~metadb_io_callback_dynamic_impl_base();
+
+	PFC_CLASS_NOT_COPYABLE_EX(metadb_io_callback_dynamic_impl_base)
+};
+
+//! \since 1.1
+//! Callback service receiving notifications about user-triggered tag edits. \n
+//! You want to use metadb_io_callback instead most of the time, unless you specifically want to track tag edits for purposes other than updating user interface.
+class NOVTABLE metadb_io_edit_callback : public service_base {
+	FB2K_MAKE_SERVICE_INTERFACE_ENTRYPOINT(metadb_io_edit_callback)
+public:
+	//! Called after the user has edited tags on a set of files.
+	typedef const pfc::list_base_const_t<const file_info*>& t_infosref;
+	virtual void on_edited(metadb_handle_list_cref items, t_infosref before, t_infosref after) = 0;
+};
+
+//! \since 2.0
+class NOVTABLE metadb_io_edit_callback_v2 : public metadb_io_edit_callback {
+	FB2K_MAKE_SERVICE_INTERFACE(metadb_io_edit_callback_v2, metadb_io_edit_callback)
+public:
+	//! With original on_edited(), the implementation could not tell what the info in metadb was before, 'before' parameter being actual infos freshly read from the file prior to writing. \n
+	//! on_edited_v2() clarifies this, additional argument passes old metadb state to deal with cases where it was different than file contents.
+	virtual void on_edited_v2(metadb_handle_list_cref items, t_infosref before, t_infosref after, t_infosref beforeInMetadb) = 0;
+};
+
+//! \since 2.0
+//! Parameter for on_changed_sorted_v2()
+class NOVTABLE metadb_io_callback_v2_data {
+public:
+	virtual metadb_v2_rec_t get(size_t idxInList) = 0;
+	metadb_v2_rec_t operator[](size_t i) { return get(i); }
+};
+
+//! \since 2.0
+//! Extended version of metadb_io_callback.
+class NOVTABLE metadb_io_callback_v2 : public metadb_io_callback {
+	FB2K_MAKE_SERVICE_INTERFACE(metadb_io_callback_v2, metadb_io_callback);
+public:
+	virtual void on_changed_sorted_v2(metadb_handle_list_cref itemsSorted, metadb_io_callback_v2_data & data, bool bFromHook) = 0;
+	//! Controls callback merit, see: fb2k::callback_merit_t
+	virtual fb2k::callback_merit_t get_callback_merit() { return fb2k::callback_merit_default; }
+};
+
+//! \since 2.0
+//! NEW interface introduced in late 2.0. \n
+//! Invoked *BEFORE* actual update, with incoming info. \n
+//! Note that incoming info may be partial (either main info or browse info not set), in such cases the info will remain unchanged.
+class NOVTABLE metadb_pre_update_callback : public service_base {
+	FB2K_MAKE_SERVICE_INTERFACE_ENTRYPOINT( metadb_pre_update_callback );
+public:
+	virtual void will_update( metadb_handle_list_cref itemsSorted, metadb_io_callback_v2_data & data) = 0;
+};
+
+//! \since 2.0
+//! Extended version of metadb_io_callback_dynamic.
+class NOVTABLE metadb_io_callback_v2_dynamic {
+public:
+	virtual void on_changed_sorted_v2(metadb_handle_list_cref itemsSorted, metadb_io_callback_v2_data & data, bool bFromHook) = 0;
+	//! Controls callback merit, see: fb2k::callback_merit_t
+	virtual fb2k::callback_merit_t get_callback_merit() { return fb2k::callback_merit_default; }
+
+	bool try_register_callback(); void try_unregister_callback();
+	void register_callback(); void unregister_callback();
+};
+
+class metadb_io_callback_v2_dynamic_impl_base : public metadb_io_callback_v2_dynamic {
+public:
+	void on_changed_sorted_v2(metadb_handle_list_cref itemsSorted, metadb_io_callback_v2_data& data, bool bFromHook) override { (void)itemsSorted; (void)data; (void)bFromHook; }
+
+	metadb_io_callback_v2_dynamic_impl_base();
+	~metadb_io_callback_v2_dynamic_impl_base();
+
+	PFC_CLASS_NOT_COPYABLE_EX(metadb_io_callback_v2_dynamic_impl_base)
+};