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comparison tools/modtrace.lua @ 11200:bf8f2da84007

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Merge 0.11->trunk
author Kim Alvefur <zash@zash.se>
date Thu, 05 Nov 2020 22:31:25 +0100
parents 50f182931bdd
children 39ae08180c81
comparison
equal deleted inserted replaced
11199:6c7c50a4de32 11200:bf8f2da84007
1 -- Trace module calls and method calls on created objects
2 --
3 -- Very rough and for debugging purposes only. It makes many
4 -- assumptions and there are many ways it could fail.
5 --
6 -- Example use:
7 --
8 -- local dbuffer = require "tools.modtrace".trace("util.dbuffer");
9 --
10
11 local t_pack = require "util.table".pack;
12 local serialize = require "util.serialization".serialize;
13 local unpack = table.unpack or unpack; --luacheck: ignore 113
14 local set = require "util.set";
15
16 local serialize_cfg = {
17 preset = "oneline";
18 freeze = true;
19 fatal = false;
20 fallback = function (v) return "<"..tostring(v)..">" end;
21 };
22
23 local function stringify_value(v)
24 if type(v) == "string" and #v > 20 then
25 return ("<string(%d)>"):format(#v);
26 elseif type(v) == "function" then
27 return tostring(v);
28 end
29 return serialize(v, serialize_cfg);
30 end
31
32 local function stringify_params(...)
33 local n = select("#", ...);
34 local r = {};
35 for i = 1, n do
36 table.insert(r, stringify_value((select(i, ...))));
37 end
38 return table.concat(r, ", ");
39 end
40
41 local function stringify_result(ret)
42 local r = {};
43 for i = 1, ret.n do
44 table.insert(r, stringify_value(ret[i]));
45 end
46 return table.concat(r, ", ");
47 end
48
49 local function stringify_call(method_name, ...)
50 return ("%s(%s)"):format(method_name, stringify_params(...));
51 end
52
53 local function wrap_method(original_obj, original_method, method_name)
54 method_name = ("<%s>:%s"):format(getmetatable(original_obj).__name or "object", method_name);
55 return function (new_obj_self, ...)
56 local opts = new_obj_self._modtrace_opts;
57 local f = opts.output or io.stderr;
58 f:write(stringify_call(method_name, ...));
59 local ret = t_pack(original_method(original_obj, ...));
60 if ret.n > 0 then
61 f:write(" = ", stringify_result(ret), "\n");
62 else
63 f:write("\n");
64 end
65 return unpack(ret, 1, ret.n);
66 end;
67 end
68
69 local function wrap_function(original_function, function_name, opts)
70 local f = opts.output or io.stderr;
71 return function (...)
72 f:write(stringify_call(function_name, ...));
73 local ret = t_pack(original_function(...));
74 if ret.n > 0 then
75 f:write(" = ", stringify_result(ret), "\n");
76 else
77 f:write("\n");
78 end
79 return unpack(ret, 1, ret.n);
80 end;
81 end
82
83 local function wrap_metamethod(name, method)
84 if name == "__index" then
85 return function (new_obj, k)
86 local original_method;
87 if type(method) == "table" then
88 original_method = new_obj._modtrace_original_obj[k];
89 else
90 original_method = method(new_obj._modtrace_original_obj, k);
91 end
92 if original_method == nil then
93 return nil;
94 end
95 return wrap_method(new_obj._modtrace_original_obj, original_method, k);
96 end;
97 end
98 return function (new_obj, ...)
99 return method(new_obj._modtrace_original_obj, ...);
100 end;
101 end
102
103 local function wrap_mt(original_mt)
104 local new_mt = {};
105 for k, v in pairs(original_mt) do
106 new_mt[k] = wrap_metamethod(k, v);
107 end
108 return new_mt;
109 end
110
111 local function wrap_obj(original_obj, opts)
112 local new_mt = wrap_mt(getmetatable(original_obj));
113 return setmetatable({_modtrace_original_obj = original_obj, _modtrace_opts = opts}, new_mt);
114 end
115
116 local function wrap_new(original_new, function_name, opts)
117 local f = opts.output or io.stderr;
118 return function (...)
119 f:write(stringify_call(function_name, ...));
120 local ret = t_pack(original_new(...));
121 local obj = ret[1];
122
123 if ret.n == 1 and type(ret[1]) == "table" then
124 f:write(" = <", getmetatable(ret[1]).__name or "object", ">", "\n");
125 elseif ret.n > 0 then
126 f:write(" = ", stringify_result(ret), "\n");
127 else
128 f:write("\n");
129 end
130
131 if obj then
132 ret[1] = wrap_obj(obj, opts);
133 end
134 return unpack(ret, 1, ret.n);
135 end;
136 end
137
138 local function trace(module, opts)
139 if type(module) == "string" then
140 module = require(module);
141 end
142 opts = opts or {};
143 local new_methods = set.new(opts.new_methods or {"new"});
144 local fake_module = setmetatable({}, {
145 __index = function (_, k)
146 if new_methods:contains(k) then
147 return wrap_new(module[k], k, opts);
148 else
149 return wrap_function(module[k], k, opts);
150 end
151 end;
152 });
153 return fake_module;
154 end
155
156 return {
157 wrap = trace;
158 trace = trace;
159 }