frontend-tools: Add "instant replay" script

A script that plays back the last replay buffer in the specified media
source.

UI/frontend-plugins/frontend-tools/data/scripts/instant-replay.lua

+obs         = obslua
+source_name = ""
+hotkey_id   = obs.OBS_INVALID_HOTKEY_ID
+
+----------------------------------------------------------
+
+-- The "Play Last Replay Buffer" hotkey callback
+function play(pressed)
+	if not pressed then
+		return
+	end
+
+	local replay_buffer = obs.obs_frontend_get_replay_buffer_output()
+	if replay_buffer == nil then
+		return
+	end
+
+	local ph = obs.obs_output_get_proc_handler(replay_buffer)
+
+	-- Call the procedure of the replay buffer named "get_last_replay" to
+	-- get the last replay created by the replay buffer
+	local cd = obs.calldata_create()
+	obs.proc_handler_call(ph, "get_last_replay", cd)
+	local path = obs.calldata_string(cd, "path")
+	obs.calldata_destroy(cd)
+
+	-- If the path is valid and the source exists, update it with the
+	-- replay file to play back the replay
+	if path ~= nil then
+		local source = obs.obs_get_source_by_name(source_name)
+		if source ~= nil then
+			local settings = obs.obs_data_create()
+			obs.obs_data_set_string(settings, "local_file", path)
+			obs.obs_data_set_bool(settings, "is_local_file", true)
+			obs.obs_data_set_bool(settings, "close_when_inactive", true)
+			obs.obs_data_set_bool(settings, "restart_on_activate", true)
+
+			-- updating will automatically cause the source to
+			-- refresh if the source is currently active, otherwise
+			-- the source will play whenever its scene is activated
+			obs.obs_source_update(source, settings)
+
+			obs.obs_data_release(settings)
+			obs.obs_source_release(source)
+		end
+	end
+
+	obs.obs_output_release(replay_buffer)
+end
+
+----------------------------------------------------------
+
+-- A function named script_update will be called when settings are changed
+function script_update(settings)
+	source_name = obs.obs_data_get_string(settings, "source")
+end
+
+-- A function named script_description returns the description shown to
+-- the user
+function script_description()
+	return "Plays the last replay buffer in the specified media source when the user presses a hotkey.\n\nMade by Jim"
+end
+
+-- A function named script_properties defines the properties that the user
+-- can change for the entire script module itself
+function script_properties()
+	props = obs.obs_properties_create()
+
+	local p = obs.obs_properties_add_list(props, "source", "Media Source", obs.OBS_COMBO_TYPE_EDITABLE, obs.OBS_COMBO_FORMAT_STRING)
+	local sources = obs.obs_enum_sources()
+	if sources ~= nil then
+		for _, source in ipairs(sources) do
+			source_id = obs.obs_source_get_id(source)
+			if source_id == "ffmpeg_source" then
+				local name = obs.obs_source_get_name(source)
+				obs.obs_property_list_add_string(p, name, name)
+			end
+		end
+	end
+	obs.source_list_release(sources)
+
+	return props
+end
+
+-- A function named script_load will be called on startup
+function script_load(settings)
+	hotkey_id = obs.obs_hotkey_register_frontend("instant_replay.play", "Play Last Replay Buffer", play)
+	local hotkey_save_array = obs.obs_data_get_array(settings, "instant_replay.play")
+	obs.obs_hotkey_load(hotkey_id, hotkey_save_array)
+	obs.obs_data_array_release(hotkey_save_array)
+end
+
+-- A function named script_save will be called when the script is saved
+--
+-- NOTE: This function is usually used for saving extra data (such as in this
+-- case, a hotkey's save data).  Settings set via the properties are saved
+-- automatically.
+function script_save(settings)
+	local hotkey_save_array = obs.obs_hotkey_save(hotkey_id)
+	obs.obs_data_set_array(settings, "instant_replay.play", hotkey_save_array)
+	obs.obs_data_array_release(hotkey_save_array)
+end