File

util/format.lua @ 11503:7adda14945ad

mod_http_file_share: Include expiry time of the upload itself in token Lets an external upload service know this so it can do expiry itself. Could possibly have been calculated based on the token expiry or issuance time, explicit > implicit.
author Kim Alvefur <zash@zash.se>
date Mon, 05 Apr 2021 17:21:18 +0200
parent 10035:386f085820e6
child 11638:5f4a657136bc
line wrap: on
line source

--
-- A string.format wrapper that gracefully handles invalid arguments
--

local tostring = tostring;
local unpack = table.unpack or unpack; -- luacheck: ignore 113/unpack
local pack = require "util.table".pack; -- TODO table.pack in 5.2+
local type = type;
local dump = require "util.serialization".new("debug");
local num_type = math.type or function (n)
	return n % 1 == 0 and n <= 9007199254740992 and n >= -9007199254740992 and "integer" or "float";
end

-- In Lua 5.3+ these formats throw an error if given a float
local expects_integer = { c = true, d = true, i = true, o = true, u = true, X = true, x = true, };

local function format(formatstring, ...)
	local args = pack(...);
	local args_length = args.n;

	-- format specifier spec:
	-- 1. Start: '%%'
	-- 2. Flags: '[%-%+ #0]'
	-- 3. Width: '%d?%d?'
	-- 4. Precision: '%.?%d?%d?'
	-- 5. Option: '[cdiouxXaAeEfgGqs%%]'
	--
	-- The options c, d, E, e, f, g, G, i, o, u, X, and x all expect a number as argument, whereas q and s expect a string.
	-- This function does not accept string values containing embedded zeros, except as arguments to the q option.
	-- a and A are only in Lua 5.2+


	-- process each format specifier
	local i = 0;
	formatstring = formatstring:gsub("%%[^cdiouxXaAeEfgGqs%%]*[cdiouxXaAeEfgGqs%%]", function(spec)
		if spec ~= "%%" then
			i = i + 1;
			local arg = args[i];

			local option = spec:sub(-1);
			if arg == nil then
				args[i] = "nil";
				spec = "<%s>";
			elseif option == "q" then
				args[i] = dump(arg);
				spec = "%s";
			elseif option == "s" then
				args[i] = tostring(arg);
			elseif type(arg) ~= "number" then -- arg isn't number as expected?
				args[i] = tostring(arg);
				spec = "[%s]";
			elseif expects_integer[option] and num_type(arg) ~= "integer" then
				args[i] = tostring(arg);
				spec = "[%s]";
			end
		end
		return spec;
	end);

	-- process extra args
	while i < args_length do
		i = i + 1;
		local arg = args[i];
		if arg == nil then
			args[i] = "<nil>";
		else
			args[i] = tostring(arg);
		end
		formatstring = formatstring .. " [%s]"
	end

	return formatstring:format(unpack(args));
end

return {
	format = format;
};