ldd-CC/API/skynet.lua

-- Skynet was created by Gollark
-- This version was modified to include CBOR in the same file

local CBOR = (function()
	-- Concise Binary Object Representation (CBOR)
	-- RFC 7049

	local function softreq(pkg, field)
		local ok, mod = pcall(require, pkg);
		if not ok then return end
		if field then return mod[field]; end
		return mod;
	end
	local dostring = function (s)
		local ok, f = pcall(loadstring or load, s); -- luacheck: read globals loadstring
		if ok and f then return f(); end
	end

	local setmetatable, getmetatable = setmetatable, getmetatable;
	local dbg_getmetatable
	-- if debug then dbg_getmetatable = debug.getmetatable else dbg_getmetatable = getmetatable end
	local assert = assert;
	local error = error;
	local type = type;
	local pairs = pairs;
	local ipairs = ipairs;
	local tostring = tostring;
	local s_char = string.char;
	local t_concat = table.concat;
	local t_sort = table.sort;
	local m_floor = math.floor;
	local m_abs = math.abs;
	local m_huge = math.huge;
	local m_max = math.max;
	local maxint = math.maxinteger or 9007199254740992;
	local minint = math.mininteger or -9007199254740992;
	local NaN = 0/0;
	local m_frexp = math.frexp;
	local m_ldexp = math.ldexp or function (x, exp) return x * 2.0 ^ exp; end;
	local m_type = math.type or function (n) return n % 1 == 0 and n <= maxint and n >= minint and "integer" or "float" end;
	local s_pack = string.pack or softreq("struct", "pack");
	local s_unpack = string.unpack or softreq("struct", "unpack");
	local b_rshift = softreq("bit32", "rshift") or softreq("bit", "rshift") or
		dostring "return function(a,b) return a >> b end" or
		function (a, b) return m_max(0, m_floor(a / (2 ^ b))); end;

	-- sanity check
	if s_pack and s_pack(">I2", 0) ~= "\0\0" then
		s_pack = nil;
	end
	if s_unpack and s_unpack(">I2", "\1\2\3\4") ~= 0x102 then
		s_unpack = nil;
	end

	local _ENV = nil; -- luacheck: ignore 211

	local encoder = {};

	local function encode(obj, opts)
		return encoder[type(obj)](obj, opts);
	end

	-- Major types 0, 1 and length encoding for others
	local function integer(num, m)
		if m == 0 and num < 0 then
			-- negative integer, major type 1
			num, m = - num - 1, 32;
		end
		if num < 24 then
			return s_char(m + num);
		elseif num < 2 ^ 8 then
			return s_char(m + 24, num);
		elseif num < 2 ^ 16 then
			return s_char(m + 25, b_rshift(num, 8), num % 0x100);
		elseif num < 2 ^ 32 then
			return s_char(m + 26,
				b_rshift(num, 24) % 0x100,
				b_rshift(num, 16) % 0x100,
				b_rshift(num, 8) % 0x100,
				num % 0x100);
		elseif num < 2 ^ 64 then
			local high = m_floor(num / 2 ^ 32);
			num = num % 2 ^ 32;
			return s_char(m + 27,
				b_rshift(high, 24) % 0x100,
				b_rshift(high, 16) % 0x100,
				b_rshift(high, 8) % 0x100,
				high % 0x100,
				b_rshift(num, 24) % 0x100,
				b_rshift(num, 16) % 0x100,
				b_rshift(num, 8) % 0x100,
				num % 0x100);
		end
		error "int too large";
	end

	if s_pack then
		function integer(num, m)
			local fmt;
			m = m or 0;
			if num < 24 then
				fmt, m = ">B", m + num;
			elseif num < 256 then
				fmt, m = ">BB", m + 24;
			elseif num < 65536 then
				fmt, m = ">BI2", m + 25;
			elseif num < 4294967296 then
				fmt, m = ">BI4", m + 26;
			else
				fmt, m = ">BI8", m + 27;
			end
			return s_pack(fmt, m, num);
		end
	end

	local simple_mt = {};
	function simple_mt:__tostring() return self.name or ("simple(%d)"):format(self.value); end
	function simple_mt:__tocbor() return self.cbor or integer(self.value, 224); end

	local function simple(value, name, cbor)
		assert(value >= 0 and value <= 255, "bad argument #1 to 'simple' (integer in range 0..255 expected)");
		return setmetatable({ value = value, name = name, cbor = cbor }, simple_mt);
	end

	local tagged_mt = {};
	function tagged_mt:__tostring() return ("%d(%s)"):format(self.tag, tostring(self.value)); end
	function tagged_mt:__tocbor() return integer(self.tag, 192) .. encode(self.value); end

	local function tagged(tag, value)
		assert(tag >= 0, "bad argument #1 to 'tagged' (positive integer expected)");
		return setmetatable({ tag = tag, value = value }, tagged_mt);
	end

	local null = simple(22, "null"); -- explicit null
	local undefined = simple(23, "undefined"); -- undefined or nil
	local BREAK = simple(31, "break", "\255");

	-- Number types dispatch
	function encoder.number(num)
		return encoder[m_type(num)](num);
	end

	-- Major types 0, 1
	function encoder.integer(num)
		if num < 0 then
			return integer(-1 - num, 32);
		end
		return integer(num, 0);
	end

	-- Major type 7
	function encoder.float(num)
		if num ~= num then -- NaN shortcut
			return "\251\127\255\255\255\255\255\255\255";
		end
		local sign = (num > 0 or 1 / num > 0) and 0 or 1;
		num = m_abs(num)
		if num == m_huge then
			return s_char(251, sign * 128 + 128 - 1) .. "\240\0\0\0\0\0\0";
		end
		local fraction, exponent = m_frexp(num)
		if fraction == 0 then
			return s_char(251, sign * 128) .. "\0\0\0\0\0\0\0";
		end
		fraction = fraction * 2;
		exponent = exponent + 1024 - 2;
		if exponent <= 0 then
			fraction = fraction * 2 ^ (exponent - 1)
			exponent = 0;
		else
			fraction = fraction - 1;
		end
		return s_char(251,
			sign * 2 ^ 7 + m_floor(exponent / 2 ^ 4) % 2 ^ 7,
			exponent % 2 ^ 4 * 2 ^ 4 +
			m_floor(fraction * 2 ^ 4 % 0x100),
			m_floor(fraction * 2 ^ 12 % 0x100),
			m_floor(fraction * 2 ^ 20 % 0x100),
			m_floor(fraction * 2 ^ 28 % 0x100),
			m_floor(fraction * 2 ^ 36 % 0x100),
			m_floor(fraction * 2 ^ 44 % 0x100),
			m_floor(fraction * 2 ^ 52 % 0x100)
		)
	end

	if s_pack then
		function encoder.float(num)
			return s_pack(">Bd", 251, num);
		end
	end


	-- Major type 2 - byte strings
	function encoder.bytestring(s)
		return integer(#s, 64) .. s;
	end

	-- Major type 3 - UTF-8 strings
	function encoder.utf8string(s)
		return integer(#s, 96) .. s;
	end

	function encoder.string(s)
		if s:match "^[\0-\127]*$" then -- If string is entirely ASCII characters, then treat it as a UTF-8 string
			return encoder.utf8string(s)
		else
			return encoder.bytestring(s)
		end
	end

	function encoder.boolean(bool)
		return bool and "\245" or "\244";
	end

	encoder["nil"] = function() return "\246"; end

	function encoder.userdata(ud, opts)
		local mt = dbg_getmetatable(ud);
		if mt then
			local encode_ud = opts and opts[mt] or mt.__tocbor;
			if encode_ud then
				return encode_ud(ud, opts);
			end
		end
		error "can't encode userdata";
	end

	function encoder.table(t, opts)
		local mt = getmetatable(t);
		if mt then
			local encode_t = opts and opts[mt] or mt.__tocbor;
			if encode_t then
				return encode_t(t, opts);
			end
		end
		-- the table is encoded as an array iff when we iterate over it,
		-- we see succesive integer keys starting from 1.  The lua
		-- language doesn't actually guarantee that this will be the case
		-- when we iterate over a table with successive integer keys, but
		-- due an implementation detail in PUC Rio Lua, this is what we
		-- usually observe.  See the Lua manual regarding the # (length)
		-- operator.  In the case that this does not happen, we will fall
		-- back to a map with integer keys, which becomes a bit larger.
		local array, map, i, p = { integer(#t, 128) }, { "\191" }, 1, 2;
		local is_array = true;
		for k, v in pairs(t) do
			is_array = is_array and i == k;
			i = i + 1;

			local encoded_v = encode(v, opts);
			array[i] = encoded_v;

			map[p], p = encode(k, opts), p + 1;
			map[p], p = encoded_v, p + 1;
		end
		-- map[p] = "\255";
		map[1] = integer(i - 1, 160);
		return t_concat(is_array and array or map);
	end

	-- Array or dict-only encoders, which can be set as __tocbor metamethod
	function encoder.array(t, opts)
		local array = { };
		for i, v in ipairs(t) do
			array[i] = encode(v, opts);
		end
		return integer(#array, 128) .. t_concat(array);
	end

	function encoder.map(t, opts)
		local map, p, len = { "\191" }, 2, 0;
		for k, v in pairs(t) do
			map[p], p = encode(k, opts), p + 1;
			map[p], p = encode(v, opts), p + 1;
			len = len + 1;
		end
		-- map[p] = "\255";
		map[1] = integer(len, 160);
		return t_concat(map);
	end
	encoder.dict = encoder.map; -- COMPAT

	function encoder.ordered_map(t, opts)
		local map = {};
		if not t[1] then -- no predefined order
			local i = 0;
			for k in pairs(t) do
				i = i + 1;
				map[i] = k;
			end
			t_sort(map);
		end
		for i, k in ipairs(t[1] and t or map) do
			map[i] = encode(k, opts) .. encode(t[k], opts);
		end
		return integer(#map, 160) .. t_concat(map);
	end

	encoder["function"] = function ()
		error "can't encode function";
	end

	-- Decoder
	-- Reads from a file-handle like object
	local function read_bytes(fh, len)
		return fh:read(len);
	end

	local function read_byte(fh)
		return fh:read(1):byte();
	end

	local function read_length(fh, mintyp)
		if mintyp < 24 then
			return mintyp;
		elseif mintyp < 28 then
			local out = 0;
			for _ = 1, 2 ^ (mintyp - 24) do
				out = out * 256 + read_byte(fh);
			end
			return out;
		else
			error "invalid length";
		end
	end

	local decoder = {};

	local function read_type(fh)
		local byte = read_byte(fh);
		return b_rshift(byte, 5), byte % 32;
	end

	local function read_object(fh, opts)
		local typ, mintyp = read_type(fh);
		return decoder[typ](fh, mintyp, opts);
	end

	local function read_integer(fh, mintyp)
		return read_length(fh, mintyp);
	end

	local function read_negative_integer(fh, mintyp)
		return -1 - read_length(fh, mintyp);
	end

	local function read_string(fh, mintyp)
		if mintyp ~= 31 then
			return read_bytes(fh, read_length(fh, mintyp));
		end
		local out = {};
		local i = 1;
		local v = read_object(fh);
		while v ~= BREAK do
			out[i], i = v, i + 1;
			v = read_object(fh);
		end
		return t_concat(out);
	end

	local function read_unicode_string(fh, mintyp)
		return read_string(fh, mintyp);
	end

	local function read_array(fh, mintyp, opts)
		local out = {};
		if mintyp == 31 then
			local i = 1;
			local v = read_object(fh, opts);
			while v ~= BREAK do
				out[i], i = v, i + 1;
				v = read_object(fh, opts);
			end
		else
			local len = read_length(fh, mintyp);
			for i = 1, len do
				out[i] = read_object(fh, opts);
			end
		end
		return out;
	end

	local function read_map(fh, mintyp, opts)
		local out = {};
		local k;
		if mintyp == 31 then
			local i = 1;
			k = read_object(fh, opts);
			while k ~= BREAK do
				out[k], i = read_object(fh, opts), i + 1;
				k = read_object(fh, opts);
			end
		else
			local len = read_length(fh, mintyp);
			for _ = 1, len do
				k = read_object(fh, opts);
				out[k] = read_object(fh, opts);
			end
		end
		return out;
	end

	local tagged_decoders = {};

	local function read_semantic(fh, mintyp, opts)
		local tag = read_length(fh, mintyp);
		local value = read_object(fh, opts);
		local postproc = opts and opts[tag] or tagged_decoders[tag];
		if postproc then
			return postproc(value);
		end
		return tagged(tag, value);
	end

	local function read_half_float(fh)
		local exponent = read_byte(fh);
		local fraction = read_byte(fh);
		local sign = exponent < 128 and 1 or -1; -- sign is highest bit

		fraction = fraction + (exponent * 256) % 1024; -- copy two(?) bits from exponent to fraction
		exponent = b_rshift(exponent, 2) % 32; -- remove sign bit and two low bits from fraction;

		if exponent == 0 then
			return sign * m_ldexp(fraction, -24);
		elseif exponent ~= 31 then
			return sign * m_ldexp(fraction + 1024, exponent - 25);
		elseif fraction == 0 then
			return sign * m_huge;
		else
			return NaN;
		end
	end

	local function read_float(fh)
		local exponent = read_byte(fh);
		local fraction = read_byte(fh);
		local sign = exponent < 128 and 1 or -1; -- sign is highest bit
		exponent = exponent * 2 % 256 + b_rshift(fraction, 7);
		fraction = fraction % 128;
		fraction = fraction * 256 + read_byte(fh);
		fraction = fraction * 256 + read_byte(fh);

		if exponent == 0 then
			return sign * m_ldexp(exponent, -149);
		elseif exponent ~= 0xff then
			return sign * m_ldexp(fraction + 2 ^ 23, exponent - 150);
		elseif fraction == 0 then
			return sign * m_huge;
		else
			return NaN;
		end
	end

	local function read_double(fh)
		local exponent = read_byte(fh);
		local fraction = read_byte(fh);
		local sign = exponent < 128 and 1 or -1; -- sign is highest bit

		exponent = exponent %  128 * 16 + b_rshift(fraction, 4);
		fraction = fraction % 16;
		fraction = fraction * 256 + read_byte(fh);
		fraction = fraction * 256 + read_byte(fh);
		fraction = fraction * 256 + read_byte(fh);
		fraction = fraction * 256 + read_byte(fh);
		fraction = fraction * 256 + read_byte(fh);
		fraction = fraction * 256 + read_byte(fh);

		if exponent == 0 then
			return sign * m_ldexp(exponent, -149);
		elseif exponent ~= 0xff then
			return sign * m_ldexp(fraction + 2 ^ 52, exponent - 1075);
		elseif fraction == 0 then
			return sign * m_huge;
		else
			return NaN;
		end
	end


	if s_unpack then
		function read_float(fh) return s_unpack(">f", read_bytes(fh, 4)) end
		function read_double(fh) return s_unpack(">d", read_bytes(fh, 8)) end
	end

	local function read_simple(fh, value, opts)
		if value == 24 then
			value = read_byte(fh);
		end
		if value == 20 then
			return false;
		elseif value == 21 then
			return true;
		elseif value == 22 then
			return null;
		elseif value == 23 then
			return undefined;
		elseif value == 25 then
			return read_half_float(fh);
		elseif value == 26 then
			return read_float(fh);
		elseif value == 27 then
			return read_double(fh);
		elseif value == 31 then
			return BREAK;
		end
		if opts and opts.simple then
			return opts.simple(value);
		end
		return simple(value);
	end

	decoder[0] = read_integer;
	decoder[1] = read_negative_integer;
	decoder[2] = read_string;
	decoder[3] = read_unicode_string;
	decoder[4] = read_array;
	decoder[5] = read_map;
	decoder[6] = read_semantic;
	decoder[7] = read_simple;

	-- opts.more(n) -> want more data
	-- opts.simple -> decode simple value
	-- opts[int] -> tagged decoder
	local function decode(s, opts)
		local fh = {};
		local pos = 1;

		local more;
		if type(opts) == "function" then
			more = opts;
		elseif type(opts) == "table" then
			more = opts.more;
		elseif opts ~= nil then
			error(("bad argument #2 to 'decode' (function or table expected, got %s)"):format(type(opts)));
		end
		if type(more) ~= "function" then
			function more()
				error "input too short";
			end
		end

		function fh:read(bytes)
			local ret = s:sub(pos, pos + bytes - 1);
			if #ret < bytes then
				ret = more(bytes - #ret, fh, opts);
				if ret then self:write(ret); end
				return self:read(bytes);
			end
			pos = pos + bytes;
			return ret;
		end

		function fh:write(bytes) -- luacheck: no self
			s = s .. bytes;
			if pos > 256 then
				s = s:sub(pos + 1);
				pos = 1;
			end
			return #bytes;
		end

		return read_object(fh, opts);
	end

	return {
		-- en-/decoder functions
		encode = encode;
		decode = decode;
		decode_file = read_object;

		-- tables of per-type en-/decoders
		type_encoders = encoder;
		type_decoders = decoder;

		-- special treatment for tagged values
		tagged_decoders = tagged_decoders;

		-- constructors for annotated types
		simple = simple;
		tagged = tagged;

		-- pre-defined simple values
		null = null;
		undefined = undefined;
	};
end)()

local skynet = {
	server = "wss://osmarks.tk/skynet2/connect/",
	socket = nil,
	open_channels = {},
	CBOR = CBOR
}

function skynet.connect(force)
	if not skynet.socket or force then
		-- If we already have a socket and are throwing it away, close old one.
		if skynet.socket then skynet.socket.close() end
		local sock = http.websocket(skynet.server)
		if not sock then error "Skynet server unavailable, broken or running newer protocol version." end
		skynet.socket = sock
		
		for _, c in pairs(skynet.open_channels) do
			skynet.open(c)	
		end
	end
end

function skynet.disconnect()
	if skynet.socket then skynet.socket.close() end
end

local function value_in_table(t, v)
	for k, tv in pairs(t) do if tv == v then return true, k end end
	return false
end

local function send_raw(data, tries)
	local tries = tries or 0
	skynet.connect()
	local ok, err = pcall(skynet.socket.send, CBOR.encode(data), true) -- send in binary mode
	if not ok then
		if tries > 0 then sleep(tries) end
		if tries > 5 then error("Max reconnection attempts exceeded. " .. err) end
		pcall(skynet.connect, true) -- attempt to force reconnect
		send_raw(data, tries + 1)
	end
end

-- Opens the given channel
function skynet.open(channel)
	-- Don't send unnecessary channel-open messages
	if not value_in_table(skynet.open_channels, channel) then
		send_raw {
			"open",
			channel
		}
		table.insert(skynet.open_channels, channel)
	end
end

local function recv_one(filter)
	skynet.connect()
	while true do
		local contents = skynet.socket.receive()
		local result = CBOR.decode(contents)
		if type(result) == "table" then
			if result[1] == "error" then error(result[2] .. ": " .. result[3]) end
			if filter(result) then
				return result
			end
		end
	end
end

local function recv_message(channel)
	local m = recv_one(function(msg)
		return msg[1] == "message" and (channel == nil or msg[2].channel == channel)
	end)
	return m[2].channel, m[2].message, m[2]
end

function skynet.logs(start, end_)
	error "The Skynet server no longer supports log retrieval"
end

local listener_running = false
-- Converts "websocket_message"s into "skynet_message"s.
function skynet.listen(force_run)
	local function run()
		while true do
			os.queueEvent("skynet_message", recv_message())	
		end
	end
	if not listener_running or force_run then
		local ok, err = pcall(run)
		listener_running = false
		if not ok then
			error(err)
		end
	end
end

-- Receives one message on given channel
-- Will open channel if it is not already open
-- Returns the channel, message, and full message object
function skynet.receive(channel)
	if channel then skynet.open(channel) end
	return recv_message(channel)
end

-- Send given data on given channel
-- Can accept a third argument - an object of extra metadata to send
function skynet.send(channel, data, full)
	local obj = full or {}
	obj.message = data
	obj.channel = channel
	send_raw {
		"message",
		obj
	}
end

return skynet