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/*
===============================================================================
Copyright (C) 2024 benoit Germain <bnt.germain@gmail.com>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
===============================================================================
*/
#include "_pch.h"
#include "nameof.h"
#include "tools.h"
// #################################################################################################
// Return some name helping to identify an object
[[nodiscard]] static int DiscoverObjectNameRecur(lua_State* L_, int shortest_, int depth_)
{
static constexpr int kWhat{ 1 }; // the object to investigate // L_: o "r" {c} {fqn} ... {?}
static constexpr int kResult{ 2 }; // where the result string is stored
static constexpr int kCache{ 3 }; // a cache
static constexpr int kFQN{ 4 }; // the name compositing stack
// no need to scan this table if the name we will discover is longer than one we already know
if (shortest_ <= depth_ + 1) {
return shortest_;
}
STACK_GROW(L_, 3);
STACK_CHECK_START_REL(L_, 0);
// stack top contains the table to search in
lua_pushvalue(L_, -1); // L_: o "r" {c} {fqn} ... {?} {?}
lua_rawget(L_, kCache); // L_: o "r" {c} {fqn} ... {?} nil/1
// if table is already visited, we are done
if (!lua_isnil(L_, -1)) {
lua_pop(L_, 1); // L_: o "r" {c} {fqn} ... {?}
return shortest_;
}
// examined table is not in the cache, add it now
lua_pop(L_, 1); // L_: o "r" {c} {fqn} ... {?}
lua_pushvalue(L_, -1); // L_: o "r" {c} {fqn} ... {?} {?}
lua_pushinteger(L_, 1); // L_: o "r" {c} {fqn} ... {?} {?} 1
lua_rawset(L_, kCache); // L_: o "r" {c} {fqn} ... {?}
// scan table contents
lua_pushnil(L_); // L_: o "r" {c} {fqn} ... {?} nil
while (lua_next(L_, -2)) { // L_: o "r" {c} {fqn} ... {?} k v
// std::string_view const _strKey{ (luaG_type(L_, -2) == LuaType::STRING) ? luaG_tostring(L_, -2) : "" }; // only for debugging
// lua_Number const numKey = (luaG_type(L_, -2) == LuaType::NUMBER) ? lua_tonumber(L_, -2) : -6666; // only for debugging
STACK_CHECK(L_, 2);
// append key name to fqn stack
++depth_;
lua_pushvalue(L_, -2); // L_: o "r" {c} {fqn} ... {?} k v k
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k v
if (lua_rawequal(L_, -1, kWhat)) { // is it what we are looking for?
STACK_CHECK(L_, 2);
// update shortest name
if (depth_ < shortest_) {
shortest_ = depth_;
std::ignore = tools::PushFQN(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k v "fqn"
lua_replace(L_, kResult); // L_: o "r" {c} {fqn} ... {?} k v
}
// no need to search further at this level
lua_pop(L_, 2); // L_: o "r" {c} {fqn} ... {?}
STACK_CHECK(L_, 0);
break;
}
switch (luaG_type(L_, -1)) { // L_: o "r" {c} {fqn} ... {?} k v
default: // nil, boolean, light userdata, number and string aren't identifiable
break;
case LuaType::TABLE: // L_: o "r" {c} {fqn} ... {?} k {}
STACK_CHECK(L_, 2);
shortest_ = DiscoverObjectNameRecur(L_, shortest_, depth_);
// search in the table's metatable too
if (lua_getmetatable(L_, -1)) { // L_: o "r" {c} {fqn} ... {?} k {} {mt}
if (lua_istable(L_, -1)) {
++depth_;
luaG_pushstring(L_, "__metatable"); // L_: o "r" {c} {fqn} ... {?} k {} {mt} "__metatable"
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k {} {mt}
shortest_ = DiscoverObjectNameRecur(L_, shortest_, depth_);
lua_pushnil(L_); // L_: o "r" {c} {fqn} ... {?} k {} {mt} nil
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k {} {mt}
--depth_;
}
lua_pop(L_, 1); // L_: o "r" {c} {fqn} ... {?} k {}
}
STACK_CHECK(L_, 2);
break;
case LuaType::THREAD: // L_: o "r" {c} {fqn} ... {?} k T
// TODO: explore the thread's stack frame looking for our culprit?
break;
case LuaType::USERDATA: // L_: o "r" {c} {fqn} ... {?} k U
STACK_CHECK(L_, 2);
// search in the object's metatable (some modules are built that way)
if (lua_getmetatable(L_, -1)) { // L_: o "r" {c} {fqn} ... {?} k U {mt}
if (lua_istable(L_, -1)) {
++depth_;
luaG_pushstring(L_, "__metatable"); // L_: o "r" {c} {fqn} ... {?} k U {mt} "__metatable"
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k U {mt}
shortest_ = DiscoverObjectNameRecur(L_, shortest_, depth_);
lua_pushnil(L_); // L_: o "r" {c} {fqn} ... {?} k U {mt} nil
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k U {mt}
--depth_;
}
lua_pop(L_, 1); // L_: o "r" {c} {fqn} ... {?} k U
}
STACK_CHECK(L_, 2);
// search in the object's uservalues
{
int _uvi{ 1 };
while (lua_getiuservalue(L_, -1, _uvi) != LUA_TNONE) { // L_: o "r" {c} {fqn} ... {?} k U {u}
if (lua_istable(L_, -1)) { // if it is a table, look inside
++depth_;
luaG_pushstring(L_, "uservalue"); // L_: o "r" {c} {fqn} ... {?} k v {u} "uservalue"
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k v {u}
shortest_ = DiscoverObjectNameRecur(L_, shortest_, depth_);
lua_pushnil(L_); // L_: o "r" {c} {fqn} ... {?} k v {u} nil
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k v {u}
--depth_;
}
lua_pop(L_, 1); // L_: o "r" {c} {fqn} ... {?} k U
++_uvi;
}
// when lua_getiuservalue() returned LUA_TNONE, it pushed a nil. pop it now
lua_pop(L_, 1); // L_: o "r" {c} {fqn} ... {?} k U
}
STACK_CHECK(L_, 2);
break;
}
// make ready for next iteration
lua_pop(L_, 1); // L_: o "r" {c} {fqn} ... {?} k
// remove name from fqn stack
lua_pushnil(L_); // L_: o "r" {c} {fqn} ... {?} k nil
lua_rawseti(L_, kFQN, depth_); // L_: o "r" {c} {fqn} ... {?} k
STACK_CHECK(L_, 1);
--depth_;
} // L_: o "r" {c} {fqn} ... {?}
STACK_CHECK(L_, 0);
// remove the visited table from the cache, in case a shorter path to the searched object exists
lua_pushvalue(L_, -1); // L_: o "r" {c} {fqn} ... {?} {?}
lua_pushnil(L_); // L_: o "r" {c} {fqn} ... {?} {?} nil
lua_rawset(L_, kCache); // L_: o "r" {c} {fqn} ... {?}
STACK_CHECK(L_, 0);
return shortest_;
}
// #################################################################################################
// "type", "name" = lanes.nameof(o)
LUAG_FUNC(nameof)
{
int const _what{ lua_gettop(L_) };
if (_what > 1) {
raise_luaL_argerror(L_, _what, "too many arguments.");
}
// nil, boolean, light userdata, number and string aren't identifiable
if (luaG_type(L_, 1) < LuaType::TABLE) {
lua_pushstring(L_, luaL_typename(L_, 1)); // L_: o "type"
lua_insert(L_, -2); // L_: "type" o
return 2;
}
STACK_GROW(L_, 4);
STACK_CHECK_START_REL(L_, 0);
// this slot will contain the shortest name we found when we are done
lua_pushnil(L_); // L_: o nil
// push a cache that will contain all already visited tables
lua_newtable(L_); // L_: o nil {c}
// push a table whose contents are strings that, when concatenated, produce unique name
lua_newtable(L_); // L_: o nil {c} {fqn}
// {fqn}[1] = "_G"
luaG_pushstring(L_, LUA_GNAME); // L_: o nil {c} {fqn} "_G"
lua_rawseti(L_, -2, 1); // L_: o nil {c} {fqn}
// this is where we start the search
luaG_pushglobaltable(L_); // L_: o nil {c} {fqn} _G
std::ignore = DiscoverObjectNameRecur(L_, std::numeric_limits<int>::max(), 1);
if (lua_isnil(L_, 2)) { // try again with registry, just in case...
lua_pop(L_, 1); // L_: o nil {c} {fqn}
luaG_pushstring(L_, "_R"); // L_: o nil {c} {fqn} "_R"
lua_rawseti(L_, -2, 1); // L_: o nil {c} {fqn}
lua_pushvalue(L_, LUA_REGISTRYINDEX); // L_: o nil {c} {fqn} _R
std::ignore = DiscoverObjectNameRecur(L_, std::numeric_limits<int>::max(), 1);
}
lua_pop(L_, 3); // L_: o "result"
STACK_CHECK(L_, 1);
lua_pushstring(L_, luaL_typename(L_, 1)); // L_: o "result" "type"
lua_replace(L_, -3); // L_: "type" "result"
return 2;
}
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