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|
/**
* @file lua_function.cpp
* @author Nat Goodspeed
* @date 2024-02-05
* @brief Implementation for lua_function.
*
* $LicenseInfo:firstyear=2024&license=viewerlgpl$
* Copyright (c) 2024, Linden Research, Inc.
* $/LicenseInfo$
*/
// Precompiled header
#include "linden_common.h"
// associated header
#include "lua_function.h"
// STL headers
// std headers
#include <algorithm>
#include <exception>
#include <iomanip> // std::quoted
#include <map>
#include <memory> // std::unique_ptr
#include <typeinfo>
#include <unordered_map>
// external library headers
// other Linden headers
#include "commoncontrol.h"
#include "fsyspath.h"
#include "hexdump.h"
#include "llcoros.h"
#include "lleventcoro.h"
#include "llsd.h"
#include "llsdutil.h"
#include "llstring.h"
#include "lualistener.h"
#include "stringize.h"
using namespace std::literals; // e.g. std::string_view literals: "this"sv
const S32 INTERRUPTS_MAX_LIMIT = 100000;
const S32 INTERRUPTS_SUSPEND_LIMIT = 100;
#define lua_register(L, n, f) (lua_pushcfunction(L, (f), n), lua_setglobal(L, (n)))
#define lua_rawlen lua_objlen
int DistinctInt::mValues{0};
/*****************************************************************************
* lluau namespace
*****************************************************************************/
namespace
{
// can't specify free function free() as a unique_ptr deleter
struct freer
{
void operator()(void* ptr){ free(ptr); }
};
} // anonymous namespace
namespace lluau
{
int dostring(lua_State* L, const std::string& desc, const std::string& text,
const std::vector<std::string>& args)
{
auto r = loadstring(L, desc, text);
if (r != LUA_OK)
return r;
// Push debug.traceback() onto the stack as lua_pcall()'s error
// handler function. On error, lua_pcall() calls the specified error
// handler function with the original error message; the message
// returned by the error handler is then returned by lua_pcall().
// Luau's debug.traceback() is called with a message to prepend to the
// returned traceback string. Almost as if they'd been designed to
// work together...
lua_getglobal(L, "debug");
lua_getfield(L, -1, "traceback");
// ditch "debug"
lua_remove(L, -2);
// stack: compiled chunk, debug.traceback()
lua_insert(L, -2);
// stack: debug.traceback(), compiled chunk
// capture absolute index of debug.traceback()
int traceback = lua_absindex(L, -2);
// remove it from stack on exit
LuaRemover cleanup(L, traceback);
// push any args passed -- all strings -- script must handle any desired
// conversions
for (const auto& arg : args)
{
lua_pushstdstring(L, arg);
}
// It's important to pass LUA_MULTRET as the expected number of return
// values: if we pass any fixed number, we discard any returned values
// beyond that number.
return lua_pcall(L, int(args.size()), LUA_MULTRET, traceback);
}
int loadstring(lua_State *L, const std::string &desc, const std::string &text)
{
size_t bytecodeSize = 0;
// The char* returned by luau_compile() must be freed by calling free().
// Use unique_ptr so the memory will be freed even if luau_load() throws.
std::unique_ptr<char[], freer> bytecode{
luau_compile(text.data(), text.length(), nullptr, &bytecodeSize)};
return luau_load(L, desc.data(), bytecode.get(), bytecodeSize, 0);
}
fsyspath source_path(lua_State* L)
{
//Luau lua_Debug and lua_getinfo() are different compared to default Lua:
//see https://github.com/luau-lang/luau/blob/80928acb92d1e4b6db16bada6d21b1fb6fa66265/VM/include/lua.h
// In particular:
// passing level=1 gets you info about the deepest function call
// passing level=lua_stackdepth() gets you info about the topmost script
// Empirically, lua_getinfo(level > 1) behaves strangely (including
// crashing the program) unless you iterate from 1 to desired level.
lua_Debug ar{};
for (int i(0), depth(lua_stackdepth(L)); i <= depth; ++i)
{
lua_getinfo(L, i, "s", &ar);
}
return ar.source;
}
} // namespace lluau
/*****************************************************************************
* lua_destroyuserdata(), lua_destroybounduserdata() (see lua_emplace<T>())
*****************************************************************************/
int lua_destroyuserdata(lua_State* L)
{
// stack: lua_emplace() userdata to be destroyed
if (int tag;
lua_isuserdata(L, -1) &&
(tag = lua_userdatatag(L, -1)) != 0)
{
auto dtor = lua_getuserdatadtor(L, tag);
// detach this userdata from the destructor with tag 'tag'
lua_setuserdatatag(L, -1, 0);
// now run the real destructor
dtor(L, lua_touserdata(L, -1));
}
lua_settop(L, 0);
return 0;
}
int lua_destroybounduserdata(lua_State *L)
{
// called with no arguments -- push bound upvalue
lluau_checkstack(L, 1);
lua_pushvalue(L, lua_upvalueindex(1));
return lua_destroyuserdata(L);
}
/*****************************************************************************
* Lua <=> C++ conversions
*****************************************************************************/
std::string lua_tostdstring(lua_State* L, int index)
{
lua_checkdelta(L);
size_t len;
const char* strval{ lua_tolstring(L, index, &len) };
return { strval, len };
}
void lua_pushstdstring(lua_State* L, const std::string& str)
{
lua_checkdelta(L, 1);
lluau_checkstack(L, 1);
lua_pushlstring(L, str.c_str(), str.length());
}
// By analogy with existing lua_tomumble() functions, return an LLSD object
// corresponding to the Lua object at stack index 'index' in state L.
// This function assumes that a Lua caller is fully aware that they're trying
// to call a viewer function. In other words, the caller must specifically
// construct Lua data convertible to LLSD.
//
// For proper error handling, we REQUIRE that the Lua runtime be compiled as
// C++ so errors are raised as C++ exceptions rather than as longjmp() calls:
// http://www.lua.org/manual/5.4/manual.html#4.4
// "Internally, Lua uses the C longjmp facility to handle errors. (Lua will
// use exceptions if you compile it as C++; search for LUAI_THROW in the
// source code for details.)"
// Some blocks within this function construct temporary C++ objects in the
// expectation that these objects will be properly destroyed even if code
// reached by that block raises a Lua error.
LLSD lua_tollsd(lua_State* L, int index)
{
lua_checkdelta(L);
switch (lua_type(L, index))
{
case LUA_TNONE:
// Should LUA_TNONE be an error instead of returning isUndefined()?
case LUA_TNIL:
return {};
case LUA_TBOOLEAN:
return bool(lua_toboolean(L, index));
case LUA_TNUMBER:
{
// Vanilla Lua supports lua_tointegerx(), which tells the caller
// whether the number at the specified stack index is or is not an
// integer. Apparently the function exists but does not work right in
// Luau: it reports even non-integer numbers as integers.
// Instead, check if integer truncation leaves the number intact.
lua_Number numval{ lua_tonumber(L, index) };
lua_Integer intval{ narrow(numval) };
if (lua_Number(intval) == numval)
{
return LLSD::Integer(intval);
}
else
{
return numval;
}
}
case LUA_TSTRING:
return lua_tostdstring(L, index);
case LUA_TUSERDATA:
{
LLSD::Binary binary(lua_rawlen(L, index));
std::memcpy(binary.data(), lua_touserdata(L, index), binary.size());
return binary;
}
case LUA_TTABLE:
{
// A Lua table correctly constructed to convert to LLSD will have
// either consecutive integer keys starting at 1, which we represent
// as an LLSD array (with Lua key 1 at C++ index 0), or will have
// all string keys.
//
// In the belief that Lua table traversal skips "holes," that is, it
// doesn't report any key/value pair whose value is nil, we allow a
// table with integer keys >= 1 but with "holes." This produces an
// LLSD array with isUndefined() entries at unspecified keys. There
// would be no other way for a Lua caller to construct an
// isUndefined() LLSD array entry. However, to guard against crazy int
// keys, we forbid gaps larger than a certain size: crazy int keys
// could result in a crazy large contiguous LLSD array.
//
// Possible looseness could include:
// - A mix of integer and string keys could produce an LLSD map in
// which the integer keys are converted to string. (Key conversion
// must be performed in C++, not Lua, to avoid confusing
// lua_next().)
// - However, since in Lua t[0] and t["0"] are distinct table entries,
// do not consider converting numeric string keys to int to return
// an LLSD array.
// But until we get more experience with actual Lua scripts in
// practice, let's say that any deviation is a Lua coding error.
// An important property of the strict definition above is that most
// conforming data blobs can make a round trip across the language
// boundary and still compare equal. A non-conforming data blob would
// lose that property.
// Known exceptions to round trip identity:
// - Empty LLSD map and empty LLSD array convert to empty Lua table.
// But empty Lua table converts to isUndefined() LLSD object.
// - LLSD::Real with integer value returns as LLSD::Integer.
// - LLSD::UUID, LLSD::Date and LLSD::URI all convert to Lua string,
// and so return as LLSD::String.
// - Lua does not store any table key whose value is nil. An LLSD
// array with isUndefined() entries produces a Lua table with
// "holes" in the int key sequence; this converts back to an LLSD
// array containing corresponding isUndefined() entries -- except
// when one or more of the final entries isUndefined(). These are
// simply dropped, producing a shorter LLSD array than the original.
// - For the same reason, any keys in an LLSD map whose value
// isUndefined() are simply discarded in the converted Lua table.
// This converts back to an LLSD map lacking those keys.
// - If it's important to preserve the original length of an LLSD
// array whose final entries are undefined, or the full set of keys
// for an LLSD map some of whose values are undefined, store an
// LLSD::emptyArray() or emptyMap() instead. These will be
// represented in Lua as empty table, which should convert back to
// undefined LLSD. Naturally, though, those won't survive a second
// round trip.
// This is the most important of the lluau_checkstack() calls because a
// deeply nested Lua structure will enter this case at each level, and
// we'll need another 2 stack slots to traverse each nested table.
lluau_checkstack(L, 2);
// BEFORE we push nil to initialize the lua_next() traversal, convert
// 'index' to absolute! Our caller might have passed a relative index;
// we do, below: lua_tollsd(L, -1). If 'index' is -1, then when we
// push nil, what we find at index -1 is nil, not the table!
index = lua_absindex(L, index);
lua_pushnil(L); // first key
if (! lua_next(L, index))
{
// it's a table, but the table is empty -- no idea if it should be
// modeled as empty array or empty map -- return isUndefined(),
// which can be consumed as either
return {};
}
// key is at stack index -2, value at index -1
// from here until lua_next() returns 0, have to lua_pop(2) if we
// return early
LuaPopper popper(L, 2);
// Remember the type of the first key
auto firstkeytype{ lua_type(L, -2) };
switch (firstkeytype)
{
case LUA_TNUMBER:
{
// First Lua key is a number: try to convert table to LLSD array.
// This is tricky because we don't know in advance the size of the
// array. The Lua reference manual says that lua_rawlen() is the
// same as the length operator '#'; but the length operator states
// that it might stop at any "hole" in the subject table.
// Moreover, the Lua next() function (and presumably lua_next())
// traverses a table in unspecified order, even for numeric keys
// (emphasized in the doc).
// Make a preliminary pass over the whole table to validate and to
// collect keys.
std::vector<LLSD::Integer> keys;
// Try to determine the length of the table. If the length
// operator is truthful, avoid allocations while we grow the keys
// vector. Even if it's not, we can still grow the vector, albeit
// a little less efficiently.
keys.reserve(lua_objlen(L, index));
do
{
auto arraykeytype{ lua_type(L, -2) };
switch (arraykeytype)
{
case LUA_TNUMBER:
{
int isint;
lua_Integer intkey{ lua_tointegerx(L, -2, &isint) };
if (! isint)
{
// key isn't an integer - this doesn't fit our LLSD
// array constraints
return lluau::error(L, "Expected integer array key, got %f instead",
lua_tonumber(L, -2));
}
if (intkey < 1)
{
return lluau::error(L, "array key %d out of bounds", int(intkey));
}
keys.push_back(LLSD::Integer(intkey));
break;
}
case LUA_TSTRING:
// break out strings specially to report the value
return lluau::error(L, "Cannot convert string array key '%s' to LLSD",
lua_tostring(L, -2));
default:
return lluau::error(L, "Cannot convert %s array key to LLSD",
lua_typename(L, arraykeytype));
}
// remove value, keep key for next iteration
lua_pop(L, 1);
} while (lua_next(L, index) != 0);
popper.disarm();
// Table keys are all integers: are they reasonable integers?
// Arbitrary max: may bite us, but more likely to protect us
const size_t array_max{ 10000 };
if (keys.size() > array_max)
{
return lluau::error(L, "Conversion from Lua to LLSD array limited to %d entries",
int(array_max));
}
// We know the smallest key is >= 1. Check the largest. We also
// know the vector is NOT empty, else we wouldn't have gotten here.
std::sort(keys.begin(), keys.end());
LLSD::Integer highkey = *keys.rbegin();
if ((highkey - LLSD::Integer(keys.size())) > 100)
{
// Looks like we've gone beyond intentional array gaps into
// crazy key territory.
return lluau::error(L, "Gaps in Lua table too large for conversion to LLSD array");
}
// right away expand the result array to the size we'll need
LLSD result{ LLSD::emptyArray() };
result[highkey - 1] = LLSD();
// Traverse the table again, and this time populate result array.
lua_pushnil(L); // first key
while (lua_next(L, index))
{
// key at stack index -2, value at index -1
// We've already validated lua_tointegerx() for each key.
auto key{ lua_tointeger(L, -2) };
// Don't forget to subtract 1 from Lua key for LLSD subscript!
result[LLSD::Integer(key) - 1] = lua_tollsd(L, -1);
// remove value, keep key for next iteration
lua_pop(L, 1);
}
return result;
}
case LUA_TSTRING:
{
// First Lua key is a string: try to convert table to LLSD map
LLSD result{ LLSD::emptyMap() };
do
{
auto mapkeytype{ lua_type(L, -2) };
if (mapkeytype != LUA_TSTRING)
{
return lluau::error(L, "Cannot convert %s map key to LLSD",
lua_typename(L, mapkeytype));
}
auto key{ lua_tostdstring(L, -2) };
result[key] = lua_tollsd(L, -1);
// remove value, keep key for next iteration
lua_pop(L, 1);
} while (lua_next(L, index) != 0);
popper.disarm();
return result;
}
default:
// First Lua key isn't number or string: sorry
return lluau::error(L, "Cannot convert %s table key to LLSD",
lua_typename(L, firstkeytype));
}
}
default:
// Other Lua entities (e.g. function, C function, light userdata,
// thread, userdata) are not convertible to LLSD, indicating a coding
// error in the caller.
return lluau::error(L, "Cannot convert type %s to LLSD", luaL_typename(L, index));
}
}
// By analogy with existing lua_pushmumble() functions, push onto state L's
// stack a Lua object corresponding to the passed LLSD object.
void lua_pushllsd(lua_State* L, const LLSD& data)
{
lua_checkdelta(L, 1);
// might need 2 slots for array or map
lluau_checkstack(L, 2);
switch (data.type())
{
case LLSD::TypeUndefined:
lua_pushnil(L);
break;
case LLSD::TypeBoolean:
lua_pushboolean(L, data.asBoolean());
break;
case LLSD::TypeInteger:
lua_pushinteger(L, data.asInteger());
break;
case LLSD::TypeReal:
lua_pushnumber(L, data.asReal());
break;
case LLSD::TypeBinary:
{
auto binary{ data.asBinary() };
std::memcpy(lua_newuserdata(L, binary.size()),
binary.data(), binary.size());
break;
}
case LLSD::TypeMap:
{
// push a new table with space for our non-array keys
lua_createtable(L, 0, narrow(data.size()));
for (const auto& pair: llsd::inMap(data))
{
// push value -- so now table is at -2, value at -1
lua_pushllsd(L, pair.second);
// pop value, assign to table[key]
lua_setfield(L, -2, pair.first.c_str());
}
break;
}
case LLSD::TypeArray:
{
// push a new table with space for array entries
lua_createtable(L, narrow(data.size()), 0);
lua_Integer key{ 0 };
for (const auto& item: llsd::inArray(data))
{
// push new array value: table at -2, value at -1
lua_pushllsd(L, item);
// pop value, assign table[key] = value
lua_rawseti(L, -2, ++key);
}
break;
}
case LLSD::TypeString:
case LLSD::TypeUUID:
case LLSD::TypeDate:
case LLSD::TypeURI:
default:
{
lua_pushstdstring(L, data.asString());
break;
}
}
}
/*****************************************************************************
* LuaState class
*****************************************************************************/
namespace
{
// If we find we're running Lua scripts from more than one thread, sLuaStateMap
// should be thread_local. Until then, avoid the overhead.
using LuaStateMap = std::unordered_map<lua_State*, LuaState*>;
static LuaStateMap sLuaStateMap;
// replace table-at-index[name] with passed func,
// binding the original table-at-index[name] as func's upvalue
void replace_entry(lua_State* L, int index,
const std::string& name, lua_CFunction func);
// replacement next() function that understands setdtor() proxy args
int lua_proxydrill(lua_State* L);
// replacement pairs() function that supports __iter() metamethod
int lua_metapairs(lua_State* L);
// replacement ipairs() function that supports __index() metamethod
int lua_metaipairs(lua_State* L);
// helper for lua_metaipairs() (actual generator function)
int lua_metaipair(lua_State* L);
} // anonymous namespace
LuaState::LuaState(script_finished_fn cb):
mCallback(cb)
{
/*---------------------------- feature flag ----------------------------*/
try
{
mFeature = LL::CommonControl::get("Global", "LuaFeature").asBoolean();
}
catch (const LL::CommonControl::NoListener&)
{
// If this program doesn't have an LLViewerControlListener,
// it's probably a test program; go ahead.
mFeature = true;
}
catch (const LL::CommonControl::ParamError&)
{
// We found LLViewerControlListener, but its settings do not include
// "LuaFeature". Hmm, fishy: that feature flag was introduced at the
// same time as this code.
mFeature = false;
}
// None of the rest of this is necessary if we're not going to run anything.
if (! mFeature)
{
mError = "Lua feature disabled";
return;
}
/*---------------------------- feature flag ----------------------------*/
mState = luaL_newstate();
// Ensure that we can always find this LuaState instance, given the
// lua_State we just created or any of its coroutines.
sLuaStateMap.emplace(mState, this);
luaL_openlibs(mState);
// publish to this new lua_State all the LL entry points we defined using
// the lua_function() macro
LuaFunction::init(mState);
// Try to make print() write to our log.
lua_register(mState, "print", LuaFunction::get("print_info"));
// We don't want to have to prefix require().
lua_register(mState, "require", LuaFunction::get("require"));
// Replace certain key global functions so they understand our
// LL.setdtor() proxy objects.
// (We could also do this for selected library functions as well,
// e.g. the table, string, math libraries... let's see if needed.)
replace_entry(mState, LUA_GLOBALSINDEX, "next", lua_proxydrill);
// Replacing pairs() with lua_metapairs() makes global pairs() honor
// objects with __iter() metamethods.
replace_entry(mState, LUA_GLOBALSINDEX, "pairs", lua_metapairs);
// Replacing ipairs() with lua_metaipairs() makes global ipairs() honor
// objects with __index() metamethods -- as long as the object in question
// has no array entries (int keys) of its own. (If it does, object[i] will
// retrieve table[i] instead of calling __index(table, i).)
replace_entry(mState, LUA_GLOBALSINDEX, "ipairs", lua_metaipairs);
}
namespace
{
void replace_entry(lua_State* L, int index,
const std::string& name, lua_CFunction func)
{
index = lua_absindex(L, index);
lua_checkdelta(L);
// push the function's name string twice
lua_pushlstring(L, name.data(), name.length());
lua_pushvalue(L, -1);
// stack: name, name
// look up the existing table entry
lua_rawget(L, index);
// stack: name, original function
// bind original function as the upvalue for func()
lua_pushcclosure(L, func, (name + "()").c_str(), 1);
// stack: name, func-with-bound-original
// table[name] = func-with-bound-original
lua_rawset(L, index);
}
int lua_metapairs(lua_State* L)
{
// LuaLog debug(L, "lua_metapairs()");
// pairs(obj): object is at index 1
// How many args were we passed?
int args = lua_gettop(L);
// stack: obj, ...
if (luaL_getmetafield(L, 1, "__iter"))
{
// stack: obj, ..., getmetatable(obj).__iter
}
else
{
// Push the original pairs() function, captured as our upvalue.
lua_pushvalue(L, lua_upvalueindex(1));
// stack: obj, ..., original pairs()
}
lua_insert(L, 1);
// stack: (__iter() or pairs()), obj, ...
// call whichever function(obj, ...) (args args, up to 3 return values)
lua_call(L, args, LUA_MULTRET);
// return as many values as the selected function returned
return lua_gettop(L);
}
int lua_metaipairs(lua_State* L)
{
// LuaLog debug(L, "lua_metaipairs()");
// ipairs(obj): object is at index 1
// How many args were we passed?
int args = lua_gettop(L);
// stack: obj, ...
if (luaL_getmetafield(L, 1, "__index"))
{
// stack: obj, ..., getmetatable(obj).__index
// discard __index and everything but obj:
// we don't want to call __index(), just check its presence
lua_settop(L, 1);
// stack: obj
lua_pushcfunction(L, lua_metaipair, "lua_metaipair");
// stack: obj, lua_metaipair
lua_insert(L, 1);
// stack: lua_metaipair, obj
// push explicit 0 so lua_metaipair need not special-case nil
lua_pushinteger(L, 0);
// stack: lua_metaipair, obj, 0
return 3;
}
else // no __index() metamethod
{
// Although our lua_metaipair() function demonstrably works whether or
// not our object has an __index() metamethod, the code below assumes
// that the Lua engine may have a more efficient implementation for
// built-in ipairs() than our lua_metaipair().
// Push the original ipairs() function, captured as our upvalue.
lua_pushvalue(L, lua_upvalueindex(1));
// stack: obj, ..., original ipairs()
// Shift the stack so the original function is first.
lua_insert(L, 1);
// stack: original ipairs(), obj, ...
// Call original ipairs() with all original args, no error checking.
// Don't truncate however many values that function returns.
lua_call(L, args, LUA_MULTRET);
// Return as many values as the original function returned.
return lua_gettop(L);
}
}
int lua_metaipair(lua_State* L)
{
// LuaLog debug(L, "lua_metaipair()");
// called with (obj, previous-index)
// increment previous-index for this call
lua_Integer i = luaL_optinteger(L, 2, 0) + 1;
lua_pop(L, 1);
// stack: obj
lua_pushinteger(L, i);
// stack: obj, i
lua_pushvalue(L, -1);
// stack: obj, i, i
lua_insert(L, 1);
// stack: i, obj, i
lua_gettable(L, -2);
// stack: i, obj, obj[i] (honoring __index())
lua_remove(L, -2);
// stack: i, obj[i]
if (! lua_isnil(L, -1))
{
// great, obj[i] isn't nil: return (i, obj[i])
return 2;
}
// obj[i] is nil. ipairs() is documented to stop at the first hole,
// regardless of #obj. Clear the stack, i.e. return nil.
lua_settop(L, 0);
return 0;
}
} // anonymous namespace
LuaState::~LuaState()
{
// If we're unwinding the stack due to an exception, don't bother trying
// to call any callbacks -- either Lua or C++.
if (std::uncaught_exceptions() != 0)
return;
/*---------------------------- feature flag ----------------------------*/
if (mFeature)
/*---------------------------- feature flag ----------------------------*/
{
// We're just about to destroy this lua_State mState. Did this Lua chunk
// register any atexit() functions?
lluau_checkstack(mState, 3);
// look up Registry.atexit
lua_getfield(mState, LUA_REGISTRYINDEX, "atexit");
// stack contains Registry.atexit
if (lua_istable(mState, -1))
{
// We happen to know that Registry.atexit is built by appending array
// entries using table.insert(). That's important because it means
// there are no holes, and therefore lua_objlen() should be correct.
// That's important because we walk the atexit table backwards, to
// destroy last the things we created (passed to LL.atexit()) first.
int len(lua_objlen(mState, -1));
LL_DEBUGS("Lua") << LLCoros::getName() << ": Registry.atexit is a table with "
<< len << " entries" << LL_ENDL;
// Push debug.traceback() onto the stack as lua_pcall()'s error
// handler function. On error, lua_pcall() calls the specified error
// handler function with the original error message; the message
// returned by the error handler is then returned by lua_pcall().
// Luau's debug.traceback() is called with a message to prepend to the
// returned traceback string. Almost as if they'd been designed to
// work together...
lua_getglobal(mState, "debug");
lua_getfield(mState, -1, "traceback");
// ditch "debug"
lua_remove(mState, -2);
// stack now contains atexit, debug.traceback()
for (int i(len); i >= 1; --i)
{
lua_pushinteger(mState, i);
// stack contains Registry.atexit, debug.traceback(), i
lua_gettable(mState, -3);
// stack contains Registry.atexit, debug.traceback(), atexit[i]
// Call atexit[i](), no args, no return values.
// Use lua_pcall() because errors in any one atexit() function
// shouldn't cancel the rest of them. Pass debug.traceback() as
// the error handler function.
LL_DEBUGS("Lua") << LLCoros::getName()
<< ": calling atexit(" << i << ")" << LL_ENDL;
if (lua_pcall(mState, 0, 0, -2) != LUA_OK)
{
auto error{ lua_tostdstring(mState, -1) };
LL_WARNS("Lua") << LLCoros::getName()
<< ": atexit(" << i << ") error: " << error << LL_ENDL;
// pop error message
lua_pop(mState, 1);
}
LL_DEBUGS("Lua") << LLCoros::getName() << ": atexit(" << i << ") done" << LL_ENDL;
// lua_pcall() has already popped atexit[i]:
// stack contains atexit, debug.traceback()
}
// pop debug.traceback()
lua_pop(mState, 1);
}
// pop Registry.atexit (either table or nil)
lua_pop(mState, 1);
// with the demise of this LuaState, remove sLuaStateMap entry
sLuaStateMap.erase(mState);
lua_close(mState);
}
if (mCallback)
{
// mError potentially set by previous checkLua() call(s)
mCallback(mError);
}
}
bool LuaState::checkLua(const std::string& desc, int r)
{
if (r != LUA_OK)
{
mError = lua_tostring(mState, -1);
lua_pop(mState, 1);
LL_WARNS("Lua") << desc << ": " << mError << LL_ENDL;
return false;
}
return true;
}
std::pair<int, LLSD> LuaState::expr(const std::string& desc, const ScriptCommand& command)
{
return expr(desc, , command.args);
}
std::pair<int, LLSD> LuaState::expr(const std::string& desc, const std::string& text,
const std::vector<std::string>& args)
{
/*---------------------------- feature flag ----------------------------*/
if (! mFeature)
{
// fake an error
return { -1, stringize("Not running ", desc) };
}
/*---------------------------- feature flag ----------------------------*/
set_interrupts_counter(0);
lua_callbacks(mState)->interrupt = [](lua_State *L, int gc)
{
// skip if we're interrupting only for garbage collection
if (gc >= 0)
return;
LLCoros::checkStop();
LuaState::getParent(L).check_interrupts_counter();
};
LL_INFOS("Lua") << desc << " run" << LL_ENDL;
if (! checkLua(desc, lluau::dostring(mState, desc, text, args)))
{
LL_WARNS("Lua") << desc << " error: " << mError << LL_ENDL;
return { -1, mError };
}
// here we believe there was no error -- did the Lua fragment leave
// anything on the stack?
std::pair<int, LLSD> result{ lua_gettop(mState), {} };
LL_INFOS("Lua") << desc << " done, " << result.first << " results." << LL_ENDL;
if (result.first)
{
// aha, at least one entry on the stack!
if (result.first == 1)
{
// Don't forget that lua_tollsd() can throw Lua errors.
try
{
result.second = lua_tollsd(mState, 1);
}
catch (const std::exception& error)
{
LL_WARNS("Lua") << desc << " error converting result: " << error.what() << LL_ENDL;
// lua_tollsd() is designed to be called from a lua_function(),
// that is, from a C++ function called by Lua. In case of error,
// it throws a Lua error to be caught by the Lua runtime. expr()
// is a peculiar use case in which our C++ code is calling
// lua_tollsd() after return from the Lua runtime. We must catch
// the exception thrown for a Lua error, else it will propagate
// out to the main coroutine and terminate the viewer -- but since
// we instead of the Lua runtime catch it, our lua_State retains
// its internal error status. Any subsequent lua_pcall() calls
// with this lua_State will report error regardless of whether the
// chunk runs successfully.
return { -1, stringize(LLError::Log::classname(error), ": ", error.what()) };
}
}
else
{
// multiple entries on the stack
int index;
try
{
for (index = 1; index <= result.first; ++index)
{
result.second.append(lua_tollsd(mState, index));
}
}
catch (const std::exception& error)
{
LL_WARNS("Lua") << desc << " error converting result " << index << ": "
<< error.what() << LL_ENDL;
// see above comments regarding lua_State's error status
return { -1, stringize(LLError::Log::classname(error), ": ", error.what()) };
}
}
}
// pop everything
lua_settop(mState, 0);
return result;
}
// We think we don't need mFeature tests in the rest of these LuaState methods
// because, if expr() isn't running code, nobody should be calling any of them.
LuaListener& LuaState::obtainListener(lua_State* L)
{
lluau_checkstack(L, 2);
lua_getfield(L, LUA_REGISTRYINDEX, "LuaListener");
// compare lua_type() because lua_isuserdata() also accepts light userdata
if (lua_type(L, -1) != LUA_TUSERDATA)
{
llassert(lua_type(L, -1) == LUA_TNIL);
lua_pop(L, 1);
// push a userdata containing new LuaListener, binding L
lua_emplace<LuaListener>(L, L);
// duplicate the top stack entry so we can store one copy
lua_pushvalue(L, -1);
lua_setfield(L, LUA_REGISTRYINDEX, "LuaListener");
}
// At this point, one way or the other, the stack top should be (a Lua
// userdata containing) our LuaListener.
LuaListener* listener{ lua_toclass<LuaListener>(L, -1) };
// Since our LuaListener instance is stored in the Registry, it won't be
// garbage collected: it will be destroyed only when lua_close() clears
// out the Registry. That's why we dare pop the userdata value off the
// stack while still depending on a pointer into its data.
lua_pop(L, 1);
return *listener;
}
LuaState& LuaState::getParent(lua_State* L)
{
// Look up the LuaState instance associated with the *script*, not the
// specific Lua *coroutine*. In other words, first find this lua_State's
// main thread.
auto found{ sLuaStateMap.find(lua_mainthread(L)) };
// Our constructor creates the map entry, our destructor deletes it. As
// long as the LuaState exists, we should be able to find it. And we
// SHOULD only be talking to a lua_State managed by a LuaState instance.
llassert(found != sLuaStateMap.end());
return *found->second;
}
void LuaState::set_interrupts_counter(S32 counter)
{
mInterrupts = counter;
}
void LuaState::check_interrupts_counter()
{
// The official way to manage data associated with a lua_State is to store
// it *as* Lua data within the lua_State. But this method is called by the
// Lua engine via lua_callbacks(L)->interrupt, and empirically we've hit
// mysterious Lua data stack overflows trying to use stack-based Lua data
// access functions in that situation. It seems the Lua engine is capable
// of interrupting itself at a moment when re-entry is not valid. So only
// touch data in this LuaState.
++mInterrupts;
if (mInterrupts > INTERRUPTS_MAX_LIMIT)
{
lluau::error(mState, "Possible infinite loop, terminated.");
}
else if (mInterrupts % INTERRUPTS_SUSPEND_LIMIT == 0)
{
LL_DEBUGS("Lua") << LLCoros::getName() << " suspending at " << mInterrupts
<< " interrupts" << LL_ENDL;
llcoro::suspend();
}
}
/*****************************************************************************
* atexit()
*****************************************************************************/
lua_function(atexit, "atexit(function): "
"register Lua function to be called at script termination")
{
lua_checkdelta(L, -1);
lluau_checkstack(L, 4);
// look up the global name "table"
lua_getglobal(L, "table");
// stack contains function, table
// look up table.insert
lua_getfield(L, -1, "insert");
// stack contains function, table, table.insert
// ditch table
lua_replace(L, -2);
// stack contains function, table.insert
// find or create the "atexit" table in the Registry
luaL_newmetatable(L, "atexit");
// stack contains function, table.insert, Registry.atexit
// we were called with a Lua function to append to that Registry.atexit
// table -- push function
lua_pushvalue(L, 1); // or -3
// stack contains function, table.insert, Registry.atexit, function
// call table.insert(Registry.atexit, function)
// don't use pcall(): if there's an error, let it propagate
lua_call(L, 2, 0);
// stack contains function -- pop everything
lua_settop(L, 0);
return 0;
}
/*****************************************************************************
* LuaPopper class
*****************************************************************************/
LuaPopper::~LuaPopper()
{
// If we're unwinding the C++ stack due to an exception, don't pop!
if (std::uncaught_exceptions() == 0 && mCount)
{
lua_pop(mState, mCount);
}
}
/*****************************************************************************
* LuaFunction class
*****************************************************************************/
LuaFunction::LuaFunction(std::string_view name, lua_CFunction function,
std::string_view helptext)
{
const auto& [registry, lookup] = getState();
registry.emplace(name, Registry::mapped_type{ function, helptext });
lookup.emplace(function, name);
}
void LuaFunction::init(lua_State* L)
{
const auto& [registry, lookup] = getRState();
lluau_checkstack(L, 2);
// create LL table --
// it happens that we know exactly how many non-array members we want
lua_createtable(L, 0, int(narrow(lookup.size())));
int idx = lua_gettop(L);
for (const auto& [name, pair]: registry)
{
const auto& [funcptr, helptext] = pair;
// store funcptr in LL table with saved name
lua_pushcfunction(L, funcptr, name.c_str());
lua_setfield(L, idx, name.c_str());
}
// store LL in new lua_State's globals
lua_setglobal(L, "LL");
}
lua_CFunction LuaFunction::get(const std::string& key)
{
// use find() instead of subscripting to avoid creating an entry for
// unknown key
const auto& [registry, lookup] = getState();
auto found{ registry.find(key) };
return (found == registry.end())? nullptr : found->second.first;
}
std::pair<LuaFunction::Registry&, LuaFunction::Lookup&> LuaFunction::getState()
{
// use function-local statics to ensure they're initialized
static Registry registry;
static Lookup lookup;
return { registry, lookup };
}
/*****************************************************************************
* LuaCommand
*****************************************************************************/
LuaCommand::LuaCommand(const std::string& command)
{
}
bool LuaCommand::found() const
{
return ;
}
/*****************************************************************************
* source_path()
*****************************************************************************/
lua_function(source_path, "source_path(): return the source path of the running Lua script")
{
lua_checkdelta(L, 1);
lluau_checkstack(L, 1);
lua_pushstdstring(L, lluau::source_path(L).u8string());
return 1;
}
/*****************************************************************************
* source_dir()
*****************************************************************************/
lua_function(source_dir, "source_dir(): return the source directory of the running Lua script")
{
lua_checkdelta(L, 1);
lluau_checkstack(L, 1);
lua_pushstdstring(L, lluau::source_path(L).parent_path().u8string());
return 1;
}
/*****************************************************************************
* abspath()
*****************************************************************************/
lua_function(abspath, "abspath(path): "
"for given filesystem path relative to running script, return absolute path")
{
lua_checkdelta(L);
auto path{ lua_tostdstring(L, 1) };
lua_pop(L, 1);
lua_pushstdstring(L, (lluau::source_path(L).parent_path() / path).u8string());
return 1;
}
/*****************************************************************************
* check_stop()
*****************************************************************************/
lua_function(check_stop, "check_stop(): ensure that a Lua script responds to viewer shutdown")
{
lua_checkdelta(L);
LLCoros::checkStop();
return 0;
}
/*****************************************************************************
* help()
*****************************************************************************/
lua_function(help,
"LL.help(): list viewer's Lua functions\n"
"LL.help(function): show help string for specific function")
{
auto& luapump{ LLEventPumps::instance().obtain("lua output") };
const auto& [registry, lookup]{ LuaFunction::getRState() };
if (! lua_gettop(L))
{
// no arguments passed: list all lua_functions
for (const auto& [name, pair] : registry)
{
const auto& [fptr, helptext] = pair;
luapump.post("LL." + helptext);
}
}
else
{
// arguments passed: list each of the specified lua_functions
for (int idx = 1, top = lua_gettop(L); idx <= top; ++idx)
{
std::string arg{ stringize("<unknown ", lua_typename(L, lua_type(L, idx)), ">") };
if (lua_type(L, idx) == LUA_TSTRING)
{
arg = lua_tostdstring(L, idx);
LLStringUtil::removePrefix(arg, "LL.");
}
else if (lua_type(L, idx) == LUA_TFUNCTION)
{
// Caller passed the actual function instead of its string
// name. A Lua function is an anonymous callable object; it
// has a name only by assigment. You can't ask Lua for a
// function's name, which is why our constructor maintains a
// reverse Lookup map.
auto function{ lua_tocfunction(L, idx) };
if (auto found = lookup.find(function); found != lookup.end())
{
// okay, pass found name to lookup below
arg = found->second;
}
}
if (auto found = registry.find(arg); found != registry.end())
{
luapump.post("LL." + found->second.second);
}
else
{
luapump.post(arg + ": NOT FOUND");
}
}
// pop all arguments
lua_settop(L, 0);
}
return 0; // void return
}
/*****************************************************************************
* leaphelp()
*****************************************************************************/
lua_function(
leaphelp,
"LL.leaphelp(): list viewer's LEAP APIs\n"
"LL.leaphelp(api): show help for specific api string name")
{
LLSD request;
int top{ lua_gettop(L) };
if (top)
{
request = llsd::map("op", "getAPI", "api", lua_tostdstring(L, 1));
}
else
{
request = llsd::map("op", "getAPIs");
}
// pop all args
lua_settop(L, 0);
auto& outpump{ LLEventPumps::instance().obtain("lua output") };
auto& listener{ LuaState::obtainListener(L) };
LLEventStream replyPump("leaphelp", true);
// ask the LuaListener's LeapListener and suspend calling coroutine until reply
auto reply{ llcoro::postAndSuspend(request, listener.getCommandName(), replyPump, "reply") };
reply.erase("reqid");
if (auto error = reply["error"]; error.isString())
{
outpump.post(error.asString());
return 0;
}
if (top)
{
// caller wants a specific API
outpump.post(stringize(reply["name"].asString(), ":\n", reply["desc"].asString()));
for (const auto& opmap : llsd::inArray(reply["ops"]))
{
std::ostringstream reqstr;
auto req{ opmap["required"] };
if (req.isArray())
{
const char* sep = " (requires ";
for (const auto& [reqkey, reqval] : llsd::inMap(req))
{
reqstr << sep << reqkey;
sep = ", ";
}
reqstr << ")";
}
outpump.post(stringize("---- ", reply["key"].asString(), " == '",
opmap["name"].asString(), "'", reqstr.str(), ":\n",
opmap["desc"].asString()));
}
}
else
{
// caller wants a list of APIs
for (const auto& [name, data] : llsd::inMap(reply))
{
outpump.post(stringize("==== ", name, ":\n", data["desc"].asString()));
}
}
return 0; // void return
}
/*****************************************************************************
* setdtor
*****************************************************************************/
namespace {
// proxy userdata object returned by setdtor()
struct setdtor_refs
{
lua_State* L;
std::string desc;
// You can't directly store a Lua object in a C++ object, but you can
// create a Lua "reference" by storing the object in the Lua Registry and
// capturing its Registry index.
int objref;
int dtorref;
setdtor_refs(lua_State* L, const std::string& desc, int objref, int dtorref):
L(L),
desc(desc),
objref(objref),
dtorref(dtorref)
{}
setdtor_refs(const setdtor_refs&) = delete;
setdtor_refs& operator=(const setdtor_refs&) = delete;
~setdtor_refs();
static void push_metatable(lua_State* L);
static std::string binop(const std::string& name, const std::string& op);
static int meta__index(lua_State* L);
};
} // anonymous namespace
lua_function(
setdtor,
"setdtor(desc, obj, dtorfunc) => proxy object referencing obj and dtorfunc.\n"
"When the returned proxy object is garbage-collected, or when the script\n"
"ends, call dtorfunc(obj). String desc is logged in the error message, if any.\n"
"Use the returned proxy object (or proxy._target) like obj.\n"
"obj won't be destroyed as long as the proxy exists; it's the proxy object's\n"
"lifespan that determines when dtorfunc(obj) will be called.")
{
if (lua_gettop(L) != 3)
{
return lluau::error(L, "setdtor(desc, obj, dtor) requires exactly 3 arguments");
}
// called with (desc, obj, dtor), returns proxy object
lua_checkdelta(L, -2);
// lluau_checkstack(L, 0); // might get up to 3 stack entries
auto desc{ lua_tostdstring(L, 1) };
// Get Lua "references" for each of the object and the dtor function.
int objref = lua_ref(L, 2);
int dtorref = lua_ref(L, 3);
// Having captured each of our parameters, discard them.
lua_settop(L, 0);
// Push our setdtor_refs userdata. Not only do we want to push it on L's
// stack, but setdtor_refs's constructor itself requires L.
lua_emplace<setdtor_refs>(L, L, desc, objref, dtorref);
// stack: proxy (i.e. setdtor_refs userdata)
// have to set its metatable
lua_getfield(L, LUA_REGISTRYINDEX, "setdtor_meta");
// stack: proxy, setdtor_meta (which might be nil)
if (lua_isnil(L, -1))
{
// discard nil
lua_pop(L, 1);
// compile and push our forwarding metatable
setdtor_refs::push_metatable(L);
// stack: proxy, metatable
// duplicate metatable to save it
lua_pushvalue(L, -1);
// stack: proxy, metatable, metable
// save metatable for future calls
lua_setfield(L, LUA_REGISTRYINDEX, "setdtor_meta");
// stack: proxy, metatable
}
// stack: proxy, metatable
lua_setmetatable(L, -2);
// stack: proxy
// Because ~setdtor_refs() necessarily uses the Lua stack, the Registry et
// al., we can't let a setdtor_refs instance be destroyed by lua_close():
// the Lua environment will already be partially shut down. To destroy
// this new setdtor_refs instance BEFORE lua_close(), bind it with
// lua_destroybounduserdata() and register it with LL.atexit().
// push (the entry point for) LL.atexit()
lua_pushcfunction(L, atexit_luasub::call, "LL.atexit()");
// stack: proxy, atexit()
lua_pushvalue(L, -2);
// stack: proxy, atexit(), proxy
int tag = lua_userdatatag(L, -1);
// We don't have a lookup table to get from an int Lua userdata tag to the
// corresponding C++ typeinfo name string. We'll introduce one if we need
// it for debugging. But for this particular call, we happen to know it's
// always a setdtor_refs object.
lua_pushcclosure(L, lua_destroybounduserdata,
stringize("lua_destroybounduserdata<", tag, ">()").c_str(),
1);
// stack: proxy, atexit(), lua_destroybounduserdata
// call atexit(): one argument, no results, let error propagate
lua_call(L, 1, 0);
// stack: proxy
return 1;
}
namespace {
void setdtor_refs::push_metatable(lua_State* L)
{
lua_checkdelta(L, 1);
lluau_checkstack(L, 1);
// Ideally we want a metatable that forwards every operation on our
// setdtor_refs userdata proxy object to the original object. But the
// published C API doesn't include (e.g.) arithmetic operations on Lua
// objects, so in fact it's easier to express the desired metatable in Lua
// than in C++. We could make setdtor() depend on an external Lua module,
// but it seems less fragile to embed the Lua source code right here.
static const std::string setdtor_meta = stringize(R"-(
-- This metatable literal doesn't define __index() because that's
-- implemented in C++. We cannot, in Lua, peek into the setdtor_refs
-- userdata object to obtain objref, nor can we fetch Registry[objref].
-- So our C++ __index() metamethod recognizes access to '_target' as a
-- reference to Registry[objref].
-- The rest are defined per https://www.lua.org/manual/5.1/manual.html#2.8.
-- Luau supports destructors instead of __gc metamethod -- we rely on that!
-- We don't set __mode because our proxy is not a table. Real references
-- are stored in the wrapped table, so ITS __mode is what counts.
-- Initial definition of meta omits binary metamethods so they can bind the
-- metatable itself, as explained for binop() below.
local meta = {
__unm = function(arg)
return -arg._target
end,
__len = function(arg)
return #arg._target
end,
-- Comparison metamethods __eq(), __lt() and __le() are only called
-- when both operands have the same metamethod. For our purposes, that
-- means both operands are setdtor_refs userdata objects.
__eq = function(lhs, rhs)
return (lhs._target == rhs._target)
end,
__lt = function(lhs, rhs)
return (lhs._target < rhs._target)
end,
__le = function(lhs, rhs)
return (lhs._target <= rhs._target)
end,
__newindex = function(t, key, value)
assert(key ~= '_target',
"Don't try to replace a setdtor() proxy's _target")
t._target[key] = value
end,
__call = function(func, ...)
return func._target(...)
end,
__tostring = function(arg)
-- don't fret about arg._target's __tostring metamethod,
-- if any, because built-in tostring() deals with that
return tostring(arg._target)
end,
__iter = function(arg)
local iter = (getmetatable(arg._target) or {}).__iter
if iter then
return iter(arg._target)
else
return next, arg._target
end
end
}
)-",
binop("add", "+"),
binop("sub", "-"),
binop("mul", "*"),
binop("div", "/"),
binop("idiv", "//"),
binop("mod", "%"),
binop("pow", "^"),
binop("concat", ".."),
R"-(
return meta
)-");
// only needed for debugging binop()
// LL_DEBUGS("Lua") << setdtor_meta << LL_ENDL;
if (lluau::dostring(L, LL_PRETTY_FUNCTION, setdtor_meta) != LUA_OK)
{
// stack: error message string
lua_error(L);
}
llassert(lua_gettop(L) > 0);
llassert(lua_type(L, -1) == LUA_TTABLE);
// stack: Lua metatable compiled from setdtor_meta source
// Inject our C++ __index metamethod.
lua_rawsetfield(L, -1, "__index"sv, &setdtor_refs::meta__index);
}
// In the definition of setdtor_meta above, binary arithmethic and
// concatenation metamethods are a little funny in that we don't know a
// priori which operand is the userdata with our metatable: the metamethod
// can be invoked either way. So every such metamethod must check, which
// leads to lots of redundancy. Hence this helper function. Call it a Lua
// macro.
std::string setdtor_refs::binop(const std::string& name, const std::string& op)
{
return stringize(
" meta.__", name, " = function(lhs, rhs)\n"
" if getmetatable(lhs) == meta then\n"
" return lhs._target ", op, " rhs\n"
" else\n"
" return lhs ", op, " rhs._target\n"
" end\n"
" end\n");
}
// setdtor_refs __index() metamethod
int setdtor_refs::meta__index(lua_State* L)
{
// called with (setdtor_refs userdata, key), returns retrieved object
lua_checkdelta(L, -1);
lluau_checkstack(L, 2);
// stack: proxy, key
// get ptr to the C++ struct data
auto ptr = lua_toclass<setdtor_refs>(L, -2);
// meta__index() should NEVER be called with anything but setdtor_refs!
llassert(ptr);
// push the wrapped object
lua_getref(L, ptr->objref);
// stack: proxy, key, _target
// replace userdata with _target
lua_replace(L, -3);
// stack: _target, key
// Duplicate key because lua_tostring() converts number to string:
// if the key is (e.g.) 1, don't try to retrieve _target["1"]!
lua_pushvalue(L, -1);
// stack: _target, key, key
// recognize the special _target field
if (lua_tostdstring(L, -1) == "_target")
{
// okay, ditch both copies of "_target" string key
lua_pop(L, 2);
// stack: _target
}
else // any key but _target
{
// ditch stringized key
lua_pop(L, 1);
// stack: _target, key
// replace key with _target[key], invoking metamethod if any
lua_gettable(L, -2);
// stack: _target, _target[key]
// discard _target
lua_remove(L, -2);
// stack: _target[key]
}
return 1;
}
// replacement for global next():
// its lua_upvalueindex(1) is the original function it's replacing
int lua_proxydrill(lua_State* L)
{
// Accept however many arguments the original function normally accepts.
// If our first arg is a userdata, check if it's a setdtor_refs proxy.
// Drill through as many levels of proxy wrapper as needed.
while (const setdtor_refs* ptr = lua_toclass<setdtor_refs>(L, 1))
{
// push original object
lua_getref(L, ptr->objref);
// replace first argument with that
lua_replace(L, 1);
}
// We've reached a first argument that's not a setdtor() proxy.
// How many arguments were we passed, anyway?
int args = lua_gettop(L);
// Push the original function, captured as our upvalue.
lua_pushvalue(L, lua_upvalueindex(1));
// Shift the stack so the original function is first.
lua_insert(L, 1);
// Call the original function with all original args, no error checking.
// Don't truncate however many values that function returns.
lua_call(L, args, LUA_MULTRET);
// Return as many values as the original function returned.
return lua_gettop(L);
}
// When Lua destroys a setdtor_refs userdata object, either from garbage
// collection or from LL.atexit(lua_destroybounduserdata), it's time to keep
// its promise to call the specified Lua destructor function with the
// specified Lua object. Of course we must also delete the captured
// "references" to both objects.
setdtor_refs::~setdtor_refs()
{
lua_checkdelta(L);
lluau_checkstack(L, 2);
// push Registry[dtorref]
lua_getref(L, dtorref);
// push Registry[objref]
lua_getref(L, objref);
// free Registry[dtorref]
lua_unref(L, dtorref);
// free Registry[objref]
lua_unref(L, objref);
// call dtor(obj): one arg, no result, no error function
int rc = lua_pcall(L, 1, 0, 0);
if (rc != LUA_OK)
{
// TODO: we don't really want to propagate the error here.
// If this setdtor_refs instance is being destroyed by
// LL.atexit(), we want to continue cleanup. If it's being
// garbage-collected, the call is completely unpredictable from
// the consuming script's point of view. But what to do about this
// error?? For now, just log it.
LL_WARNS("Lua") << LLCoros::getName()
<< ": setdtor(" << std::quoted(desc) << ") error: "
<< lua_tostring(L, -1) << LL_ENDL;
lua_pop(L, 1);
}
}
} // anonymous namespace
/*****************************************************************************
* lua_what
*****************************************************************************/
std::ostream& operator<<(std::ostream& out, const lua_what& self)
{
switch (lua_type(self.L, self.index))
{
case LUA_TNONE:
// distinguish acceptable but non-valid index
out << "none";
break;
case LUA_TNIL:
out << "nil";
break;
case LUA_TBOOLEAN:
{
auto oldflags { out.flags() };
out << std::boolalpha << lua_toboolean(self.L, self.index);
out.flags(oldflags);
break;
}
case LUA_TNUMBER:
out << lua_tonumber(self.L, self.index);
break;
case LUA_TSTRING:
out << std::quoted(lua_tostdstring(self.L, self.index));
break;
case LUA_TUSERDATA:
{
const S32 maxlen = 20;
S32 binlen{ lua_rawlen(self.L, self.index) };
LLSD::Binary binary(std::min(maxlen, binlen));
std::memcpy(binary.data(), lua_touserdata(self.L, self.index), binary.size());
out << LL::hexdump(binary);
if (binlen > maxlen)
{
out << "...(" << (binlen - maxlen) << " more)";
}
break;
}
case LUA_TLIGHTUSERDATA:
out << lua_touserdata(self.L, self.index);
break;
case LUA_TFUNCTION:
{
// Try for the function's name, at the cost of a few more stack
// entries.
lua_checkdelta(self.L);
lluau_checkstack(self.L, 3);
lua_getglobal(self.L, "debug");
// stack: ..., debug
lua_getfield(self.L, -1, "info");
// stack: ..., debug, debug.info
lua_remove(self.L, -2);
// stack: ..., debug.info
lua_pushvalue(self.L, self.index);
// stack: ..., debug.info, this function
lua_pushstring(self.L, "n");
// stack: ..., debug.info, this function, "n"
// 2 arguments, 1 return value (or error message), no error handler
lua_pcall(self.L, 2, 1, 0);
// stack: ..., function name (or error) from debug.info()
out << "function " << lua_tostdstring(self.L, -1);
lua_pop(self.L, 1);
// stack: ...
break;
}
default:
// anything else, don't bother trying to report value, just type
out << lua_typename(self.L, lua_type(self.L, self.index));
break;
}
return out;
}
/*****************************************************************************
* lua_stack
*****************************************************************************/
std::ostream& operator<<(std::ostream& out, const lua_stack& self)
{
out << "stack: [";
const char* sep = "";
for (int index = 1; index <= lua_gettop(self.L); ++index)
{
out << sep << lua_what(self.L, index);
sep = ", ";
}
out << ']';
return out;
}
/*****************************************************************************
* LuaStackDelta
*****************************************************************************/
LuaStackDelta::LuaStackDelta(lua_State* L, const std::string& where, int delta):
L(L),
mWhere(where),
mDepth(lua_gettop(L)),
mDelta(delta)
{}
LuaStackDelta::~LuaStackDelta()
{
auto depth{ lua_gettop(L) };
// If we're unwinding the stack due to an exception, then of course we
// can't expect the logic in the block containing this LuaStackDelta
// instance to keep its contract wrt the Lua data stack.
if (std::uncaught_exceptions() == 0 && mDepth + mDelta != depth)
{
LL_ERRS("Lua") << LLCoros::getName() << ": " << mWhere
<< ": Lua stack went from " << mDepth << " to " << depth;
if (mDelta)
{
LL_CONT << ", rather than expected " << (mDepth + mDelta) << " (" << mDelta << ")";
}
LL_ENDL;
}
}
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