File

+
−-- Prosody IM
+
−-- Copyright (C) 2008-2010 Matthew Wild
+
−-- Copyright (C) 2008-2010 Waqas Hussain
+
−-- Copyright (C) 2018 Kim Alvefur
+
−--
+
−-- This project is MIT/X11 licensed. Please see the
+
−-- COPYING file in the source package for more information.
+
−--
+
−
+
−local getmetatable = getmetatable;
+
−local next, type = next, type;
+
−local s_format = string.format;
+
−local s_gsub = string.gsub;
+
−local s_rep = string.rep;
+
−local s_char = string.char;
+
−local s_match = string.match;
+
−local t_concat = table.concat;
+
−
+
−local to_hex = require "util.hex".to;
+
−
+
−local pcall = pcall;
+
−local envload = require"util.envload".envload;
+
−
+
−local pos_inf, neg_inf = math.huge, -math.huge;
+
−local m_type = math.type or function (n)
+
−	return n % 1 == 0 and n <= 9007199254740992 and n >= -9007199254740992 and "integer" or "float";
+
−end;
+
−
+
−local function rawpairs(t)
+
−	return next, t, nil;
+
−end
+
−
+
−local function fatal_error(obj, why)
+
−	error("Can't serialize "..type(obj) .. (why and ": ".. why or ""));
+
−end
+
−
+
−local function nonfatal_fallback(x, why)
+
−	return s_format("{__type=%q,__error=%q}", type(x), why or "fail");
+
−end
+
−
+
−local string_escapes = {
+
−	['\a'] = [[\a]]; ['\b'] = [[\b]];
+
−	['\f'] = [[\f]]; ['\n'] = [[\n]];
+
−	['\r'] = [[\r]]; ['\t'] = [[\t]];
+
−	['\v'] = [[\v]]; ['\\'] = [[\\]];
+
−	['\"'] = [[\"]]; ['\''] = [[\']];
+
−}
+
−
+
−for i = 0, 255 do
+
−	local c = s_char(i);
+
−	if not string_escapes[c] then
+
−		string_escapes[c] = s_format("\\%03d", i);
+
−	end
+
−end
+
−
+
−local default_keywords = {
+
−	["do"] = true; ["and"] = true; ["else"] = true; ["break"] = true;
+
−	["if"] = true; ["end"] = true; ["goto"] = true; ["false"] = true;
+
−	["in"] = true; ["for"] = true; ["then"] = true; ["local"] = true;
+
−	["or"] = true; ["nil"] = true; ["true"] = true; ["until"] = true;
+
−	["elseif"] = true; ["function"] = true; ["not"] = true;
+
−	["repeat"] = true; ["return"] = true; ["while"] = true;
+
−};
+
−
+
−local function new(opt)
+
−	if type(opt) ~= "table" then
+
−		opt = { preset = opt };
+
−	end
+
−
+
−	local types = {
+
−		table = true;
+
−		string = true;
+
−		number = true;
+
−		boolean = true;
+
−		["nil"] = true;
+
−	};
+
−
+
−	-- presets
+
−	if opt.preset == "debug" then
+
−		opt.preset = "oneline";
+
−		opt.freeze = true;
+
−		opt.fatal = false;
+
−		opt.fallback = nonfatal_fallback;
+
−		opt.unquoted = true;
+
−	end
+
−	if opt.preset == "oneline" then
+
−		opt.indentwith = opt.indentwith or "";
+
−		opt.itemstart = opt.itemstart or " ";
+
−		opt.itemlast = opt.itemlast or "";
+
−		opt.tend = opt.tend or " }";
+
−	elseif opt.preset == "compact" then
+
−		opt.indentwith = opt.indentwith or "";
+
−		opt.itemstart = opt.itemstart or "";
+
−		opt.itemlast = opt.itemlast or "";
+
−		opt.equals = opt.equals or "=";
+
−		opt.unquoted = true;
+
−	end
+
−
+
−	local fallback = opt.fallback or opt.fatal == false and nonfatal_fallback or fatal_error;
+
−
+
−	local function ser(v)
+
−		return (types[type(v)] or fallback)(v);
+
−	end
+
−
+
−	local keywords = opt.keywords or default_keywords;
+
−
+
−	-- indented
+
−	local indentwith = opt.indentwith or "\t";
+
−	local itemstart = opt.itemstart or "\n";
+
−	local itemsep = opt.itemsep or ";";
+
−	local itemlast = opt.itemlast or ";\n";
+
−	local tstart = opt.tstart or "{";
+
−	local tend = opt.tend or "}";
+
−	local kstart = opt.kstart or "[";
+
−	local kend = opt.kend or "]";
+
−	local equals = opt.equals or " = ";
+
−	local unquoted = opt.unquoted == true and "^[%a_][%w_]*$" or opt.unquoted;
+
−	local hex = opt.hex;
+
−	local freeze = opt.freeze;
+
−	local maxdepth = opt.maxdepth or 127;
+
−	local multirefs = opt.multiref;
+
−	local table_pairs = opt.table_iterator or rawpairs;
+
−
+
−	-- serialize one table, recursively
+
−	-- t - table being serialized
+
−	-- o - array where tokens are added, concatenate to get final result
+
−	--   - also used to detect cycles
+
−	-- l - position in o of where to insert next token
+
−	-- d - depth, used for indentation
+
−	local function serialize_table(t, o, l, d)
+
−		if o[t] then
+
−			o[l], l = fallback(t, "table has multiple references"), l + 1;
+
−			return l;
+
−		elseif d > maxdepth then
+
−			o[l], l = fallback(t, "max table depth reached"), l + 1;
+
−			return l;
+
−		end
+
−
+
−		-- Keep track of table loops
+
−		local ot = t; -- reference pre-freeze
+
−		o[t] = true;
+
−		o[ot] = true;
+
−
+
−		if freeze == true then
+
−			-- opportunity to do pre-serialization
+
−			local mt = getmetatable(t);
+
−			if type(mt) == "table" then
+
−				local tag = mt.__name;
+
−				local fr = mt.__freeze;
+
−
+
−				if type(fr) == "function" then
+
−					t = fr(t);
+
−					if type(t) == "string" then
+
−						o[l], l = t, l + 1;
+
−						return l;
+
−					end
+
−					if type(tag) == "string" then
+
−						o[l], l = tag, l + 1;
+
−					end
+
−				end
+
−			end
+
−		end
+
−
+
−		o[l], l = tstart, l + 1;
+
−		local indent = s_rep(indentwith, d);
+
−		local numkey = 1;
+
−		local ktyp, vtyp;
+
−		local had_items = false;
+
−		for k,v in table_pairs(t) do
+
−			had_items = true;
+
−			o[l], l = itemstart, l + 1;
+
−			o[l], l = indent, l + 1;
+
−			ktyp, vtyp = type(k), type(v);
+
−			if k == numkey then
+
−				-- next index in array part
+
−				-- assuming that these are found in order
+
−				numkey = numkey + 1;
+
−			elseif unquoted and ktyp == "string" and
+
−				not keywords[k] and s_match(k, unquoted) then
+
−				-- unquoted keys
+
−				o[l], l = k, l + 1;
+
−				o[l], l = equals, l + 1;
+
−			else
+
−				-- quoted keys
+
−				o[l], l = kstart, l + 1;
+
−				if ktyp == "table" then
+
−					l = serialize_table(k, o, l, d+1);
+
−				else
+
−					o[l], l = ser(k), l + 1;
+
−				end
+
−				-- =
+
−				o[l], o[l+1], l = kend, equals, l + 2;
+
−			end
+
−
+
−			-- the value
+
−			if vtyp == "table" then
+
−				l = serialize_table(v, o, l, d+1);
+
−			else
+
−				o[l], l = ser(v), l + 1;
+
−			end
+
−			o[l], l = itemsep, l + 1;
+
−		end
+
−		if had_items then
+
−			o[l - 1] = itemlast;
+
−			o[l], l = s_rep(indentwith, d-1), l + 1;
+
−		end
+
−		o[l], l = tend, l +1;
+
−
+
−		if multirefs then
+
−			o[t] = nil;
+
−			o[ot] = nil;
+
−		end
+
−
+
−		return l;
+
−	end
+
−
+
−	function types.table(t)
+
−		local o = {};
+
−		serialize_table(t, o, 1, 1);
+
−		return t_concat(o);
+
−	end
+
−
+
−	local function serialize_string(s)
+
−		return '"' .. s_gsub(s, "[%z\1-\31\"\'\\\127-\255]", string_escapes) .. '"';
+
−	end
+
−
+
−	if type(hex) == "string" then
+
−		function types.string(s)
+
−			local esc = serialize_string(s);
+
−			if #esc > (#s*2+2+#hex) then
+
−				return hex .. '"' .. to_hex(s) .. '"';
+
−			end
+
−			return esc;
+
−		end
+
−	else
+
−		types.string = serialize_string;
+
−	end
+
−
+
−	function types.number(t)
+
−		if m_type(t) == "integer" then
+
−			return s_format("%d", t);
+
−		elseif t == pos_inf then
+
−			return "(1/0)";
+
−		elseif t == neg_inf then
+
−			return "(-1/0)";
+
−		elseif t ~= t then
+
−			return "(0/0)";
+
−		end
+
−		return s_format("%.18g", t);
+
−	end
+
−
+
−	-- Are these faster than tostring?
+
−	types["nil"] = function()
+
−		return "nil";
+
−	end
+
−
+
−	function types.boolean(t)
+
−		return t and "true" or "false";
+
−	end
+
−
+
−	return ser;
+
−end
+
−
+
−local function deserialize(str)
+
−	if type(str) ~= "string" then return nil; end
+
−	str = "return "..str;
+
−	local f, err = envload(str, "=serialized data", {});
+
−	if not f then return nil, err; end
+
−	local success, ret = pcall(f);
+
−	if not success then return nil, ret; end
+
−	return ret;
+
−end
+
−
+
−local default = new();
+
−return {
+
−	new = new;
+
−	serialize = function (x, opt)
+
−		if opt == nil then
+
−			return default(x);
+
−		else
+
−			return new(opt)(x);
+
−		end
+
−	end;
+
−	deserialize = deserialize;
+
−};