prosody/util/serialization.lua
Kim Alvefur f3414a43d8 util.serialization: Add a "pretty" preset
This is the config I want 90% of the time when just showing data in the
console or so.
2023-06-09 17:26:38 +02:00

291 lines
6.8 KiB
Lua

-- 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 "prosody.util.hex".to;
local pcall = pcall;
local envload = require"prosody.util.envload".envload;
if not math.type then
require "prosody.util.mathcompat"
end
local pos_inf, neg_inf = math.huge, -math.huge;
local m_type = math.type;
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;
elseif opt.preset == "pretty" then
opt.fatal = false;
opt.freeze = true;
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;
};