aboutsummaryrefslogtreecommitdiffstats
path: root/tools/modtrace.lua
blob: 45fa9f6a385977324f90723403b1c8a0c5d95f5a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
-- Trace module calls and method calls on created objects
--
-- Very rough and for debugging purposes only. It makes many
-- assumptions and there are many ways it could fail.
--
-- Example use:
--
--   local dbuffer = require "tools.modtrace".trace("util.dbuffer");
--

local t_pack = require "util.table".pack;
local serialize = require "util.serialization".serialize;
local unpack = table.unpack or unpack; --luacheck: ignore 113
local set = require "util.set";

local serialize_cfg = {
	preset = "oneline";
	freeze = true;
	fatal = false;
	fallback = function (v) return "<"..tostring(v)..">" end;
};

local function stringify_value(v)
	if type(v) == "string" and #v > 20 then
		return ("<string(%d)>"):format(#v);
	elseif type(v) == "function" then
		return tostring(v);
	end
	return serialize(v, serialize_cfg);
end

local function stringify_params(...)
	local n = select("#", ...);
	local r = {};
	for i = 1, n do
		table.insert(r, stringify_value((select(i, ...))));
	end
	return table.concat(r, ", ");
end

local function stringify_result(ret)
	local r = {};
	for i = 1, ret.n do
		table.insert(r, stringify_value(ret[i]));
	end
	return table.concat(r, ", ");
end

local function stringify_call(method_name, ...)
	return ("%s(%s)"):format(method_name, stringify_params(...));
end

local function wrap_method(original_obj, original_method, method_name)
	method_name = ("<%s>:%s"):format(getmetatable(original_obj).__name or "object", method_name);
	return function (new_obj_self, ...)
		local opts = new_obj_self._modtrace_opts;
		local f = opts.output or io.stderr;
		f:write(stringify_call(method_name, ...));
		local ret = t_pack(original_method(original_obj, ...));
		if ret.n > 0 then
			f:write(" = ", stringify_result(ret), "\n");
		else
			f:write("\n");
		end
		return unpack(ret, 1, ret.n);
	end;
end

local function wrap_function(original_function, function_name, opts)
	local f = opts.output or io.stderr;
	return function (...)
		f:write(stringify_call(function_name, ...));
		local ret = t_pack(original_function(...));
		if ret.n > 0 then
			f:write(" = ", stringify_result(ret), "\n");
		else
			f:write("\n");
		end
		return unpack(ret, 1, ret.n);
	end;
end

local function wrap_metamethod(name, method)
	if name == "__index" then
		return function (new_obj, k)
			local original_method;
			if type(method) == "table" then
				original_method = new_obj._modtrace_original_obj[k];
			else
				original_method = method(new_obj._modtrace_original_obj, k);
			end
			if original_method == nil then
				return nil;
			end
			return wrap_method(new_obj._modtrace_original_obj, original_method, k);
		end;
	end
	return function (new_obj, ...)
		return method(new_obj._modtrace_original_obj, ...);
	end;
end

local function wrap_mt(original_mt)
	local new_mt = {};
	for k, v in pairs(original_mt) do
		new_mt[k] = wrap_metamethod(k, v);
	end
	return new_mt;
end

local function wrap_obj(original_obj, opts)
	local new_mt = wrap_mt(getmetatable(original_obj));
	return setmetatable({_modtrace_original_obj = original_obj, _modtrace_opts = opts}, new_mt);
end

local function wrap_new(original_new, function_name, opts)
	local f = opts.output or io.stderr;
	return function (...)
		f:write(stringify_call(function_name, ...));
		local ret = t_pack(original_new(...));
		local obj = ret[1];

		if ret.n == 1 and type(ret[1]) == "table" then
			f:write(" = <", getmetatable(ret[1]).__name or "object", ">", "\n");
		elseif ret.n > 0 then
			f:write(" = ", stringify_result(ret), "\n");
		else
			f:write("\n");
		end

		if obj then
			ret[1] = wrap_obj(obj, opts);
		end
		return unpack(ret, 1, ret.n);
	end;
end

local function trace(module, opts)
	if type(module) == "string" then
		module = require(module);
	end
	opts = opts or {};
	local new_methods = set.new(opts.new_methods or {"new"});
	local fake_module = setmetatable({}, {
		__index = function (_, k)
			if new_methods:contains(k) then
				return wrap_new(module[k], k, opts);
			else
				return wrap_function(module[k], k, opts);
			end
		end;
	});
	return fake_module;
end

return {
	wrap = trace;
	trace = trace;
}