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| -rw-r--r-- | tools/modtrace.lua | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/tools/modtrace.lua b/tools/modtrace.lua new file mode 100644 index 00000000..6360fb61 --- /dev/null +++ b/tools/modtrace.lua @@ -0,0 +1,152 @@ +-- 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 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, "debug"); +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; +} |