util/logger.lua

-- 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 pcall = pcall;

--local log_sources = config.get("*", "core", "log_sources");

local find = string.find;

local ipairs, pairs, setmetatable = ipairs, pairs, setmetatable;

module "logger"

local name_sinks, level_sinks = {}, {};

local name_patterns = {};

-- Weak-keyed so that loggers are collected

local modify_hooks = setmetatable({}, { __mode = "k" });

local make_logger;

local outfunction = nil;

function init(name)

	if log_sources then

		local log_this = false;

		for _, source in ipairs(log_sources) do

			if find(name, source) then 

				log_this = true;

				break;

			end

		end

		if not log_this then return function () end end

	end

	local log_debug = make_logger(name, "debug");

	local log_info = make_logger(name, "info");

	local log_warn = make_logger(name, "warn");

	local log_error = make_logger(name, "error");

	--name = nil; -- While this line is not commented, will automatically fill in file/line number info

	local namelen = #name;

	return function (level, message, ...)

			if outfunction then return outfunction(name, level, message, ...); end

			if level == "debug" then

				return log_debug(message, ...);

			elseif level == "info" then

				return log_info(message, ...);

			elseif level == "warn" then

				return log_warn(message, ...);

			elseif level == "error" then

				return log_error(message, ...);

			end

		end

end

function make_logger(source_name, level)

	local level_handlers = level_sinks[level];

	if not level_handlers then

		level_handlers = {};

		level_sinks[level] = level_handlers;

	end

	local source_handlers = name_sinks[source_name];

	-- All your premature optimisation is belong to me!

	local num_level_handlers, num_source_handlers = #level_handlers, source_handlers and #source_handlers;

	local logger = function (message, ...)

		if source_handlers then

			for i = 1,num_source_handlers do

				if source_handlers[i](source_name, level, message, ...) == false then

					return;

				end

			end

		end

		for i = 1,num_level_handlers do

			level_handlers[i](source_name, level, message, ...);

		end

	end

	-- To make sure our cached lengths stay in sync with reality

	modify_hooks[logger] = function () num_level_handlers, num_source_handlers = #level_handlers, source_handlers and #source_handlers; end; 

	return logger;

end

function setwriter(f)

	local old_func = outfunction;

	if not f then outfunction = nil; return true, old_func; end

	local ok, ret = pcall(f, "logger", "info", "Switched logging output successfully");

	if ok then

		outfunction = f;

		ret = old_func;

	end

	return ok, ret;

end

function reset()

	for k in pairs(name_sinks) do name_sinks[k] = nil; end

	for level, handler_list in pairs(level_sinks) do

		-- Clear all handlers for this level

		for i = 1, #handler_list do

			handler_list[i] = nil;

		end

	end

	for k in pairs(name_patterns) do name_patterns[k] = nil; end

	for _, modify_hook in pairs(modify_hooks) do

		modify_hook();

	end

end

function add_level_sink(level, sink_function)

	if not level_sinks[level] then

		level_sinks[level] = { sink_function };

	else

		level_sinks[level][#level_sinks[level] + 1 ] = sink_function;

	end

	for _, modify_hook in pairs(modify_hooks) do

		modify_hook();

	end

end

function add_name_sink(name, sink_function, exclusive)

	if not name_sinks[name] then

		name_sinks[name] = { sink_function };

	else

		name_sinks[name][#name_sinks[name] + 1] = sink_function;

	end

	for _, modify_hook in pairs(modify_hooks) do

		modify_hook();

	end

end

function add_name_pattern_sink(name_pattern, sink_function, exclusive)

	if not name_patterns[name_pattern] then

		name_patterns[name_pattern] = { sink_function };

	else

		name_patterns[name_pattern][#name_patterns[name_pattern] + 1] = sink_function;

	end

end

_M.new = make_logger;

return _M;