File

util/filters.lua @ 12590:5eaf77114fdb

compat: Use table.pack (there since Lua 5.2) over our util.table Added in d278a770eddc avoid having to deal with its absence in Lua 5.1. No longer needed when Lua 5.1 support is dropped.
author Kim Alvefur <zash@zash.se>
date Mon, 11 Jul 2022 19:15:24 +0200
parent 8555:4f0f5b49bb03
line wrap: on
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local t_insert, t_remove = table.insert, table.remove;

local _ENV = nil;
-- luacheck: std none

local new_filter_hooks = {};

local function initialize(session)
	if not session.filters then
		local filters = {};
		session.filters = filters;

		function session.filter(type, data)
			local filter_list = filters[type];
			if filter_list then
				for i = 1, #filter_list do
					data = filter_list[i](data, session);
					if data == nil then break; end
				end
			end
			return data;
		end
	end

	for i=1,#new_filter_hooks do
		new_filter_hooks[i](session);
	end

	return session.filter;
end

local function add_filter(session, type, callback, priority)
	if not session.filters then
		initialize(session);
	end

	local filter_list = session.filters[type];
	if not filter_list then
		filter_list = {};
		session.filters[type] = filter_list;
	elseif filter_list[callback] then
		return; -- Filter already added
	end

	priority = priority or 0;

	local i = 0;
	repeat
		i = i + 1;
	until not filter_list[i] or filter_list[filter_list[i]] < priority;

	t_insert(filter_list, i, callback);
	filter_list[callback] = priority;
end

local function remove_filter(session, type, callback)
	if not session.filters then return; end
	local filter_list = session.filters[type];
	if filter_list and filter_list[callback] then
		for i=1, #filter_list do
			if filter_list[i] == callback then
				t_remove(filter_list, i);
				filter_list[callback] = nil;
				return true;
			end
		end
	end
end

local function add_filter_hook(callback)
	t_insert(new_filter_hooks, callback);
end

local function remove_filter_hook(callback)
	for i=1,#new_filter_hooks do
		if new_filter_hooks[i] == callback then
			t_remove(new_filter_hooks, i);
		end
	end
end

return {
	initialize = initialize;
	add_filter = add_filter;
	remove_filter = remove_filter;
	add_filter_hook = add_filter_hook;
	remove_filter_hook = remove_filter_hook;
};