772 lines
28 KiB
Rust
772 lines
28 KiB
Rust
use std::any::{Any, TypeId};
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use std::borrow::Cow;
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use std::collections::HashMap;
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use std::fmt::Write;
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use std::os::raw::{c_char, c_int, c_void};
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use std::panic::{catch_unwind, resume_unwind, AssertUnwindSafe};
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use std::sync::{Arc, Mutex};
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use std::{mem, ptr, slice};
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use crate::error::{Error, Result};
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use crate::ffi;
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lazy_static::lazy_static! {
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// The capacity must(!) be greater than number of stored keys
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static ref METATABLE_CACHE: Mutex<HashMap<TypeId, u8>> = Mutex::new(HashMap::with_capacity(32));
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}
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// Checks that Lua has enough free stack space for future stack operations. On failure, this will
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// panic with an internal error message.
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pub unsafe fn assert_stack(state: *mut ffi::lua_State, amount: c_int) {
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// TODO: This should only be triggered when there is a logic error in `mlua`. In the future,
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// when there is a way to be confident about stack safety and test it, this could be enabled
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// only when `cfg!(debug_assertions)` is true.
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mlua_assert!(
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ffi::lua_checkstack(state, amount) != 0,
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"out of stack space"
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);
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}
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// Checks that Lua has enough free stack space and returns `Error::StackError` on failure.
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pub unsafe fn check_stack(state: *mut ffi::lua_State, amount: c_int) -> Result<()> {
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if ffi::lua_checkstack(state, amount) == 0 {
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Err(Error::StackError)
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} else {
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Ok(())
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}
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}
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pub struct StackGuard {
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state: *mut ffi::lua_State,
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top: c_int,
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}
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impl StackGuard {
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// Creates a StackGuard instance with wa record of the stack size, and on Drop will check the
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// stack size and drop any extra elements. If the stack size at the end is *smaller* than at
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// the beginning, this is considered a fatal logic error and will result in a panic.
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pub unsafe fn new(state: *mut ffi::lua_State) -> StackGuard {
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StackGuard {
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state,
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top: ffi::lua_gettop(state),
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}
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}
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}
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impl Drop for StackGuard {
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fn drop(&mut self) {
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unsafe {
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let top = ffi::lua_gettop(self.state);
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if top < self.top {
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mlua_panic!("{} too many stack values popped", self.top - top)
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}
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if top > self.top {
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ffi::lua_settop(self.state, self.top);
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}
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}
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}
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}
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// Call a function that calls into the Lua API and may trigger a Lua error (longjmp) in a safe way.
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// Wraps the inner function in a call to `lua_pcall`, so the inner function only has access to a
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// limited lua stack. `nargs` is the same as the the parameter to `lua_pcall`, and `nresults` is
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// always LUA_MULTRET. Internally uses 2 extra stack spaces, and does not call checkstack.
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// Provided function must *never* panic.
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pub unsafe fn protect_lua(
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state: *mut ffi::lua_State,
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nargs: c_int,
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f: unsafe extern "C" fn(*mut ffi::lua_State) -> c_int,
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) -> Result<()> {
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let stack_start = ffi::lua_gettop(state) - nargs;
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ffi::lua_pushcfunction(state, error_traceback);
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ffi::lua_pushcfunction(state, f);
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if nargs > 0 {
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ffi::lua_rotate(state, stack_start + 1, 2);
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}
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let ret = ffi::lua_pcall(state, nargs, ffi::LUA_MULTRET, stack_start + 1);
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ffi::lua_remove(state, stack_start + 1);
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if ret == ffi::LUA_OK {
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Ok(())
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} else {
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Err(pop_error(state, ret))
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}
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}
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// Call a function that calls into the Lua API and may trigger a Lua error (longjmp) in a safe way.
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// Wraps the inner function in a call to `lua_pcall`, so the inner function only has access to a
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// limited lua stack. `nargs` and `nresults` are similar to the parameters of `lua_pcall`, but the
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// given function return type is not the return value count, instead the inner function return
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// values are assumed to match the `nresults` param. Internally uses 3 extra stack spaces, and does
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// not call checkstack. Provided function must *not* panic, and since it will generally be
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// lonjmping, should not contain any values that implement Drop.
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pub unsafe fn protect_lua_closure<F, R>(
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state: *mut ffi::lua_State,
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nargs: c_int,
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nresults: c_int,
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f: F,
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) -> Result<R>
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where
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F: Fn(*mut ffi::lua_State) -> R,
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R: Copy,
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{
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union URes<R: Copy> {
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uninit: (),
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init: R,
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}
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struct Params<F, R: Copy> {
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function: F,
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result: URes<R>,
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nresults: c_int,
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}
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unsafe extern "C" fn do_call<F, R>(state: *mut ffi::lua_State) -> c_int
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where
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R: Copy,
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F: Fn(*mut ffi::lua_State) -> R,
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{
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let params = ffi::lua_touserdata(state, -1) as *mut Params<F, R>;
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ffi::lua_pop(state, 1);
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(*params).result.init = ((*params).function)(state);
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if (*params).nresults == ffi::LUA_MULTRET {
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ffi::lua_gettop(state)
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} else {
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(*params).nresults
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}
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}
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let stack_start = ffi::lua_gettop(state) - nargs;
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ffi::lua_pushcfunction(state, error_traceback);
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ffi::lua_pushcfunction(state, do_call::<F, R>);
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if nargs > 0 {
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ffi::lua_rotate(state, stack_start + 1, 2);
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}
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let mut params = Params {
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function: f,
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result: URes { uninit: () },
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nresults,
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};
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ffi::lua_pushlightuserdata(state, &mut params as *mut Params<F, R> as *mut c_void);
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let ret = ffi::lua_pcall(state, nargs + 1, nresults, stack_start + 1);
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ffi::lua_remove(state, stack_start + 1);
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if ret == ffi::LUA_OK {
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// LUA_OK is only returned when the do_call function has completed successfully, so
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// params.result is definitely initialized.
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Ok(params.result.init)
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} else {
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Err(pop_error(state, ret))
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}
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}
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// Pops an error off of the stack and returns it. The specific behavior depends on the type of the
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// error at the top of the stack:
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// 1) If the error is actually a WrappedPanic, this will continue the panic.
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// 2) If the error on the top of the stack is actually a WrappedError, just returns it.
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// 3) Otherwise, interprets the error as the appropriate lua error.
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// Uses 2 stack spaces, does not call lua_checkstack.
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pub unsafe fn pop_error(state: *mut ffi::lua_State, err_code: c_int) -> Error {
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mlua_debug_assert!(
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err_code != ffi::LUA_OK && err_code != ffi::LUA_YIELD,
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"pop_error called with non-error return code"
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);
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if let Some(err) = get_wrapped_error(state, -1).as_ref() {
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ffi::lua_pop(state, 1);
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err.clone()
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} else if let Some(panic) = get_gc_userdata::<WrappedPanic>(state, -1).as_mut() {
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if let Some(p) = (*panic).0.take() {
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resume_unwind(p);
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} else {
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mlua_panic!("error during panic handling, panic was resumed twice")
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}
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} else {
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let err_string = to_string(state, -1).into_owned();
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ffi::lua_pop(state, 1);
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match err_code {
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ffi::LUA_ERRRUN => Error::RuntimeError(err_string),
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ffi::LUA_ERRSYNTAX => {
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Error::SyntaxError {
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// This seems terrible, but as far as I can tell, this is exactly what the
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// stock Lua REPL does.
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incomplete_input: err_string.ends_with("<eof>")
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|| err_string.ends_with("'<eof>'"),
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message: err_string,
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}
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}
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ffi::LUA_ERRERR => {
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// This error is raised when the error handler raises an error too many times
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// recursively, and continuing to trigger the error handler would cause a stack
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// overflow. It is not very useful to differentiate between this and "ordinary"
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// runtime errors, so we handle them the same way.
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Error::RuntimeError(err_string)
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}
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ffi::LUA_ERRMEM => Error::MemoryError(err_string),
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#[cfg(any(feature = "lua53", feature = "lua52"))]
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ffi::LUA_ERRGCMM => Error::GarbageCollectorError(err_string),
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_ => mlua_panic!("unrecognized lua error code"),
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}
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}
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}
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// Internally uses 4 stack spaces, does not call checkstack
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pub unsafe fn push_string<S: ?Sized + AsRef<[u8]>>(
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state: *mut ffi::lua_State,
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s: &S,
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) -> Result<()> {
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protect_lua_closure(state, 0, 1, |state| {
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let s = s.as_ref();
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ffi::lua_pushlstring(state, s.as_ptr() as *const c_char, s.len());
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})
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}
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// Internally uses 4 stack spaces, does not call checkstack
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pub unsafe fn push_userdata<T>(state: *mut ffi::lua_State, t: T) -> Result<()> {
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let ud = protect_lua_closure(state, 0, 1, move |state| {
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ffi::lua_newuserdata(state, mem::size_of::<T>()) as *mut T
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})?;
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ptr::write(ud, t);
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Ok(())
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}
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pub unsafe fn get_userdata<T>(state: *mut ffi::lua_State, index: c_int) -> *mut T {
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let ud = ffi::lua_touserdata(state, index) as *mut T;
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mlua_debug_assert!(!ud.is_null(), "userdata pointer is null");
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ud
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}
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// Pops the userdata off of the top of the stack and returns it to rust, invalidating the lua
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// userdata and gives it the special "destructed" userdata metatable. Userdata must not have been
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// previously invalidated, and this method does not check for this. Uses 1 extra stack space and
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// does not call checkstack
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pub unsafe fn take_userdata<T>(state: *mut ffi::lua_State) -> T {
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// We set the metatable of userdata on __gc to a special table with no __gc method and with
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// metamethods that trigger an error on access. We do this so that it will not be double
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// dropped, and also so that it cannot be used or identified as any particular userdata type
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// after the first call to __gc.
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get_destructed_userdata_metatable(state);
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ffi::lua_setmetatable(state, -2);
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let ud = ffi::lua_touserdata(state, -1) as *mut T;
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mlua_debug_assert!(!ud.is_null(), "userdata pointer is null");
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ffi::lua_pop(state, 1);
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ptr::read(ud)
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}
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// Pushes the userdata and attaches a metatable with __gc method
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// Internally uses 5 stack spaces, does not call checkstack
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pub unsafe fn push_gc_userdata<T: Any>(state: *mut ffi::lua_State, t: T) -> Result<()> {
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push_meta_gc_userdata::<T, T>(state, t)
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}
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pub unsafe fn push_meta_gc_userdata<MT: Any, T>(state: *mut ffi::lua_State, t: T) -> Result<()> {
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let ud = protect_lua_closure(state, 0, 1, move |state| {
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ffi::lua_newuserdata(state, mem::size_of::<T>()) as *mut T
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})?;
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ptr::write(ud, t);
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get_gc_metatable_for::<MT>(state);
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ffi::lua_setmetatable(state, -2);
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Ok(())
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}
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// Uses 2 stack spaces, does not call checkstack
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pub unsafe fn get_gc_userdata<T: Any>(state: *mut ffi::lua_State, index: c_int) -> *mut T {
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get_meta_gc_userdata::<T, T>(state, index)
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}
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pub unsafe fn get_meta_gc_userdata<MT: Any, T>(state: *mut ffi::lua_State, index: c_int) -> *mut T {
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let ud = ffi::lua_touserdata(state, index) as *mut T;
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if ud.is_null() || ffi::lua_getmetatable(state, index) == 0 {
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return ptr::null_mut();
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}
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get_gc_metatable_for::<MT>(state);
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let res = ffi::lua_rawequal(state, -1, -2) != 0;
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ffi::lua_pop(state, 2);
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if !res {
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return ptr::null_mut();
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}
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ud
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}
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// Populates the given table with the appropriate members to be a userdata metatable for the given
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// type. This function takes the given table at the `metatable` index, and adds an appropriate __gc
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// member to it for the given type and a __metatable entry to protect the table from script access.
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// The function also, if given a `members` table index, will set up an __index metamethod to return
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// the appropriate member on __index. Additionally, if there is already an __index entry on the
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// given metatable, instead of simply overwriting the __index, instead the created __index method
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// will capture the previous one, and use it as a fallback only if the given key is not found in the
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// provided members table. Internally uses 6 stack spaces and does not call checkstack.
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pub unsafe fn init_userdata_metatable<T>(
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state: *mut ffi::lua_State,
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metatable: c_int,
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members: Option<c_int>,
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) -> Result<()> {
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// Used if both an __index metamethod is set and regular methods, checks methods table
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// first, then __index metamethod.
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unsafe extern "C" fn meta_index_impl(state: *mut ffi::lua_State) -> c_int {
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ffi::luaL_checkstack(state, 2, ptr::null());
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ffi::lua_pushvalue(state, -1);
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ffi::lua_gettable(state, ffi::lua_upvalueindex(2));
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if ffi::lua_isnil(state, -1) == 0 {
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ffi::lua_insert(state, -3);
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ffi::lua_pop(state, 2);
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1
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} else {
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ffi::lua_pop(state, 1);
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ffi::lua_pushvalue(state, ffi::lua_upvalueindex(1));
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ffi::lua_insert(state, -3);
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ffi::lua_call(state, 2, 1);
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1
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}
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}
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let members = members.map(|i| ffi::lua_absindex(state, i));
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ffi::lua_pushvalue(state, metatable);
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if let Some(members) = members {
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push_string(state, "__index")?;
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ffi::lua_pushvalue(state, -1);
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let index_type = ffi::lua_rawget(state, -3);
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if index_type == ffi::LUA_TNIL {
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ffi::lua_pop(state, 1);
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ffi::lua_pushvalue(state, members);
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} else if index_type == ffi::LUA_TFUNCTION {
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ffi::lua_pushvalue(state, members);
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protect_lua_closure(state, 2, 1, |state| {
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ffi::lua_pushcclosure(state, meta_index_impl, 2);
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})?;
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} else {
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mlua_panic!("improper __index type {}", index_type);
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}
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protect_lua_closure(state, 3, 1, |state| {
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ffi::lua_rawset(state, -3);
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})?;
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}
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push_string(state, "__gc")?;
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ffi::lua_pushcfunction(state, userdata_destructor::<T>);
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protect_lua_closure(state, 3, 1, |state| {
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ffi::lua_rawset(state, -3);
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})?;
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push_string(state, "__metatable")?;
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ffi::lua_pushboolean(state, 0);
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protect_lua_closure(state, 3, 1, |state| {
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ffi::lua_rawset(state, -3);
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})?;
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ffi::lua_pop(state, 1);
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Ok(())
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}
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pub unsafe extern "C" fn userdata_destructor<T>(state: *mut ffi::lua_State) -> c_int {
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callback_error(state, |_| {
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check_stack(state, 1)?;
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take_userdata::<T>(state);
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Ok(0)
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})
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}
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// In the context of a lua callback, this will call the given function and if the given function
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// returns an error, *or if the given function panics*, this will result in a call to lua_error (a
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// longjmp). The error or panic is wrapped in such a way that when calling pop_error back on
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// the rust side, it will resume the panic.
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//
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// This function assumes the structure of the stack at the beginning of a callback, that the only
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// elements on the stack are the arguments to the callback.
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//
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// This function uses some of the bottom of the stack for error handling, the given callback will be
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// given the number of arguments available as an argument, and should return the number of returns
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// as normal, but cannot assume that the arguments available start at 0.
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pub unsafe fn callback_error<R, F>(state: *mut ffi::lua_State, f: F) -> R
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where
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F: FnOnce(c_int) -> Result<R>,
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{
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let nargs = ffi::lua_gettop(state);
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// We need one extra stack space to store preallocated memory, and at least 3 stack spaces
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// overall for handling error metatables
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let extra_stack = if nargs < 3 { 3 - nargs } else { 1 };
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ffi::luaL_checkstack(
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state,
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extra_stack,
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cstr!("not enough stack space for callback error handling"),
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);
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// We cannot shadow rust errors with Lua ones, we pre-allocate enough memory to store a wrapped
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// error or panic *before* we proceed.
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let ud = ffi::lua_newuserdata(
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state,
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mem::size_of::<WrappedError>().max(mem::size_of::<WrappedPanic>()),
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);
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ffi::lua_rotate(state, 1, 1);
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match catch_unwind(AssertUnwindSafe(|| f(nargs))) {
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Ok(Ok(r)) => {
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ffi::lua_remove(state, 1);
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r
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}
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Ok(Err(err)) => {
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ffi::lua_settop(state, 1);
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ptr::write(ud as *mut WrappedError, WrappedError(err));
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get_gc_metatable_for::<WrappedError>(state);
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ffi::lua_setmetatable(state, -2);
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ffi::lua_error(state)
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}
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Err(p) => {
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ffi::lua_settop(state, 1);
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ptr::write(ud as *mut WrappedPanic, WrappedPanic(Some(p)));
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get_gc_metatable_for::<WrappedPanic>(state);
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ffi::lua_setmetatable(state, -2);
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ffi::lua_error(state)
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}
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}
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}
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// Takes an error at the top of the stack, and if it is a WrappedError, converts it to an
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// Error::CallbackError with a traceback, if it is some lua type, prints the error along with a
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// traceback, and if it is a WrappedPanic, does not modify it. This function does its best to avoid
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// triggering another error and shadowing previous rust errors, but it may trigger Lua errors that
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// shadow rust errors under certain memory conditions. This function ensures that such behavior
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|
// will *never* occur with a rust panic, however.
|
|
pub unsafe extern "C" fn error_traceback(state: *mut ffi::lua_State) -> c_int {
|
|
// I believe luaL_traceback requires this much free stack to not error.
|
|
const LUA_TRACEBACK_STACK: c_int = 11;
|
|
|
|
if ffi::lua_checkstack(state, 2) == 0 {
|
|
// If we don't have enough stack space to even check the error type, do nothing so we don't
|
|
// risk shadowing a rust panic.
|
|
} else if let Some(error) = get_wrapped_error(state, -1).as_ref() {
|
|
// lua_newuserdata and luaL_traceback may error, but nothing that implements Drop should be
|
|
// on the rust stack at this time.
|
|
let ud = ffi::lua_newuserdata(state, mem::size_of::<WrappedError>()) as *mut WrappedError;
|
|
let traceback = if ffi::lua_checkstack(state, LUA_TRACEBACK_STACK) != 0 {
|
|
ffi::luaL_traceback(state, state, ptr::null(), 0);
|
|
|
|
let traceback = to_string(state, -1).into_owned();
|
|
ffi::lua_pop(state, 1);
|
|
traceback
|
|
} else {
|
|
"<not enough stack space for traceback>".to_owned()
|
|
};
|
|
|
|
let error = error.clone();
|
|
ffi::lua_remove(state, -2);
|
|
|
|
ptr::write(
|
|
ud,
|
|
WrappedError(Error::CallbackError {
|
|
traceback,
|
|
cause: Arc::new(error),
|
|
}),
|
|
);
|
|
get_gc_metatable_for::<WrappedError>(state);
|
|
ffi::lua_setmetatable(state, -2);
|
|
} else if get_gc_userdata::<WrappedPanic>(state, -1).is_null()
|
|
&& ffi::lua_checkstack(state, LUA_TRACEBACK_STACK) != 0
|
|
{
|
|
let s = ffi::luaL_tolstring(state, -1, ptr::null_mut());
|
|
ffi::luaL_traceback(state, state, s, 0);
|
|
ffi::lua_remove(state, -2);
|
|
}
|
|
1
|
|
}
|
|
|
|
// Does not call lua_checkstack, uses 1 stack space.
|
|
pub unsafe fn get_main_state(state: *mut ffi::lua_State) -> Option<*mut ffi::lua_State> {
|
|
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
|
|
{
|
|
ffi::lua_rawgeti(state, ffi::LUA_REGISTRYINDEX, ffi::LUA_RIDX_MAINTHREAD);
|
|
let main_state = ffi::lua_tothread(state, -1);
|
|
ffi::lua_pop(state, 1);
|
|
Some(main_state)
|
|
}
|
|
#[cfg(any(feature = "lua51", feature = "luajit"))]
|
|
{
|
|
// Check the current state first
|
|
let is_main_state = ffi::lua_pushthread(state) == 1;
|
|
ffi::lua_pop(state, 1);
|
|
if is_main_state {
|
|
Some(state)
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
// Pushes a WrappedError to the top of the stack. Uses two stack spaces and does not call
|
|
// lua_checkstack.
|
|
pub unsafe fn push_wrapped_error(state: *mut ffi::lua_State, err: Error) -> Result<()> {
|
|
push_gc_userdata::<WrappedError>(state, WrappedError(err))
|
|
}
|
|
|
|
// Checks if the value at the given index is a WrappedError, and if it is returns a pointer to it,
|
|
// otherwise returns null. Uses 2 stack spaces and does not call lua_checkstack.
|
|
pub unsafe fn get_wrapped_error(state: *mut ffi::lua_State, index: c_int) -> *const Error {
|
|
let ud = get_gc_userdata::<WrappedError>(state, index);
|
|
if ud.is_null() {
|
|
return ptr::null();
|
|
}
|
|
&(*ud).0
|
|
}
|
|
|
|
// Initialize the internal (with __gc) metatable for a type T
|
|
pub unsafe fn init_gc_metatable_for<T: Any>(
|
|
state: *mut ffi::lua_State,
|
|
customize_fn: Option<fn(*mut ffi::lua_State)>,
|
|
) {
|
|
let type_id = TypeId::of::<T>();
|
|
|
|
let ref_addr = {
|
|
let mut mt_cache = mlua_expect!(METATABLE_CACHE.lock(), "cannot lock metatable cache");
|
|
mlua_assert!(
|
|
mt_cache.capacity() - mt_cache.len() > 0,
|
|
"out of metatable cache capacity"
|
|
);
|
|
mt_cache.insert(type_id, 0);
|
|
&mt_cache[&type_id] as *const u8
|
|
};
|
|
|
|
ffi::lua_newtable(state);
|
|
|
|
ffi::lua_pushstring(state, cstr!("__gc"));
|
|
ffi::lua_pushcfunction(state, userdata_destructor::<T>);
|
|
ffi::lua_rawset(state, -3);
|
|
|
|
ffi::lua_pushstring(state, cstr!("__metatable"));
|
|
ffi::lua_pushboolean(state, 0);
|
|
ffi::lua_rawset(state, -3);
|
|
|
|
if let Some(f) = customize_fn {
|
|
f(state)
|
|
}
|
|
|
|
ffi::lua_rawsetp(state, ffi::LUA_REGISTRYINDEX, ref_addr as *mut c_void);
|
|
}
|
|
|
|
pub unsafe fn get_gc_metatable_for<T: Any>(state: *mut ffi::lua_State) {
|
|
let type_id = TypeId::of::<T>();
|
|
let ref_addr = {
|
|
let mt_cache = mlua_expect!(METATABLE_CACHE.lock(), "cannot lock metatable cache");
|
|
mlua_expect!(mt_cache.get(&type_id), "gc metatable does not exist") as *const u8
|
|
};
|
|
ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, ref_addr as *mut c_void);
|
|
}
|
|
|
|
// Initialize the error, panic, and destructed userdata metatables.
|
|
pub unsafe fn init_error_registry(state: *mut ffi::lua_State) {
|
|
assert_stack(state, 8);
|
|
|
|
// Create error and panic metatables
|
|
|
|
unsafe extern "C" fn error_tostring(state: *mut ffi::lua_State) -> c_int {
|
|
let err_buf = callback_error(state, |_| {
|
|
check_stack(state, 3)?;
|
|
if let Some(error) = get_wrapped_error(state, -1).as_ref() {
|
|
ffi::lua_pushlightuserdata(
|
|
state,
|
|
&ERROR_PRINT_BUFFER_KEY as *const u8 as *mut c_void,
|
|
);
|
|
ffi::lua_rawget(state, ffi::LUA_REGISTRYINDEX);
|
|
let err_buf = ffi::lua_touserdata(state, -1) as *mut String;
|
|
ffi::lua_pop(state, 2);
|
|
|
|
(*err_buf).clear();
|
|
// Depending on how the API is used and what error types scripts are given, it may
|
|
// be possible to make this consume arbitrary amounts of memory (for example, some
|
|
// kind of recursive error structure?)
|
|
let _ = write!(&mut (*err_buf), "{}", error);
|
|
Ok(err_buf)
|
|
} else if let Some(panic) = get_gc_userdata::<WrappedPanic>(state, -1).as_ref() {
|
|
if let Some(ref p) = (*panic).0 {
|
|
ffi::lua_pushlightuserdata(
|
|
state,
|
|
&ERROR_PRINT_BUFFER_KEY as *const u8 as *mut c_void,
|
|
);
|
|
ffi::lua_rawget(state, ffi::LUA_REGISTRYINDEX);
|
|
let err_buf = ffi::lua_touserdata(state, -1) as *mut String;
|
|
ffi::lua_pop(state, 2);
|
|
|
|
let error = if let Some(x) = p.downcast_ref::<&str>() {
|
|
x.to_string()
|
|
} else if let Some(x) = p.downcast_ref::<String>() {
|
|
x.to_string()
|
|
} else {
|
|
"panic".to_string()
|
|
};
|
|
|
|
(*err_buf).clear();
|
|
let _ = write!(&mut (*err_buf), "{}", error);
|
|
Ok(err_buf)
|
|
} else {
|
|
mlua_panic!("error during panic handling, panic was resumed")
|
|
}
|
|
} else {
|
|
// I'm not sure whether this is possible to trigger without bugs in mlua?
|
|
Err(Error::UserDataTypeMismatch)
|
|
}
|
|
});
|
|
|
|
ffi::lua_pushlstring(
|
|
state,
|
|
(*err_buf).as_ptr() as *const c_char,
|
|
(*err_buf).len(),
|
|
);
|
|
(*err_buf).clear();
|
|
1
|
|
}
|
|
|
|
init_gc_metatable_for::<WrappedError>(
|
|
state,
|
|
Some(|state| {
|
|
ffi::lua_pushstring(state, cstr!("__tostring"));
|
|
ffi::lua_pushcfunction(state, error_tostring);
|
|
ffi::lua_rawset(state, -3);
|
|
}),
|
|
);
|
|
|
|
init_gc_metatable_for::<WrappedPanic>(
|
|
state,
|
|
Some(|state| {
|
|
ffi::lua_pushstring(state, cstr!("__tostring"));
|
|
ffi::lua_pushcfunction(state, error_tostring);
|
|
ffi::lua_rawset(state, -3);
|
|
}),
|
|
);
|
|
|
|
// Create destructed userdata metatable
|
|
|
|
unsafe extern "C" fn destructed_error(state: *mut ffi::lua_State) -> c_int {
|
|
ffi::luaL_checkstack(state, 2, ptr::null());
|
|
let ud = ffi::lua_newuserdata(state, mem::size_of::<WrappedError>()) as *mut WrappedError;
|
|
ptr::write(ud, WrappedError(Error::CallbackDestructed));
|
|
get_gc_metatable_for::<WrappedError>(state);
|
|
ffi::lua_setmetatable(state, -2);
|
|
ffi::lua_error(state)
|
|
}
|
|
|
|
ffi::lua_pushlightuserdata(
|
|
state,
|
|
&DESTRUCTED_USERDATA_METATABLE as *const u8 as *mut c_void,
|
|
);
|
|
ffi::lua_newtable(state);
|
|
|
|
for &method in &[
|
|
cstr!("__add"),
|
|
cstr!("__sub"),
|
|
cstr!("__mul"),
|
|
cstr!("__div"),
|
|
cstr!("__mod"),
|
|
cstr!("__pow"),
|
|
cstr!("__unm"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53"))]
|
|
cstr!("__idiv"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53"))]
|
|
cstr!("__band"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53"))]
|
|
cstr!("__bor"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53"))]
|
|
cstr!("__bxor"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53"))]
|
|
cstr!("__bnot"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53"))]
|
|
cstr!("__shl"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53"))]
|
|
cstr!("__shr"),
|
|
cstr!("__concat"),
|
|
cstr!("__len"),
|
|
cstr!("__eq"),
|
|
cstr!("__lt"),
|
|
cstr!("__le"),
|
|
cstr!("__index"),
|
|
cstr!("__newindex"),
|
|
cstr!("__call"),
|
|
cstr!("__tostring"),
|
|
#[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))]
|
|
cstr!("__pairs"),
|
|
#[cfg(any(feature = "lua53", feature = "lua52"))]
|
|
cstr!("__ipairs"),
|
|
#[cfg(feature = "lua54")]
|
|
cstr!("__close"),
|
|
] {
|
|
ffi::lua_pushstring(state, method);
|
|
ffi::lua_pushcfunction(state, destructed_error);
|
|
ffi::lua_rawset(state, -3);
|
|
}
|
|
|
|
ffi::lua_rawset(state, ffi::LUA_REGISTRYINDEX);
|
|
|
|
// Create error print buffer
|
|
|
|
ffi::lua_pushlightuserdata(state, &ERROR_PRINT_BUFFER_KEY as *const u8 as *mut c_void);
|
|
|
|
let ud = ffi::lua_newuserdata(state, mem::size_of::<String>()) as *mut String;
|
|
ptr::write(ud, String::new());
|
|
|
|
ffi::lua_newtable(state);
|
|
ffi::lua_pushstring(state, cstr!("__gc"));
|
|
ffi::lua_pushcfunction(state, userdata_destructor::<String>);
|
|
ffi::lua_rawset(state, -3);
|
|
ffi::lua_setmetatable(state, -2);
|
|
|
|
ffi::lua_rawset(state, ffi::LUA_REGISTRYINDEX);
|
|
}
|
|
|
|
struct WrappedError(pub Error);
|
|
struct WrappedPanic(pub Option<Box<dyn Any + Send + 'static>>);
|
|
|
|
// Converts the given lua value to a string in a reasonable format without causing a Lua error or
|
|
// panicking.
|
|
unsafe fn to_string<'a>(state: *mut ffi::lua_State, index: c_int) -> Cow<'a, str> {
|
|
match ffi::lua_type(state, index) {
|
|
ffi::LUA_TNONE => "<none>".into(),
|
|
ffi::LUA_TNIL => "<nil>".into(),
|
|
ffi::LUA_TBOOLEAN => (ffi::lua_toboolean(state, index) != 1).to_string().into(),
|
|
ffi::LUA_TLIGHTUSERDATA => {
|
|
format!("<lightuserdata {:?}>", ffi::lua_topointer(state, index)).into()
|
|
}
|
|
ffi::LUA_TNUMBER => {
|
|
let mut isint = 0;
|
|
let i = ffi::lua_tointegerx(state, -1, &mut isint);
|
|
if isint == 0 {
|
|
ffi::lua_tonumber(state, index).to_string().into()
|
|
} else {
|
|
i.to_string().into()
|
|
}
|
|
}
|
|
ffi::LUA_TSTRING => {
|
|
let mut size = 0;
|
|
let data = ffi::lua_tolstring(state, index, &mut size);
|
|
String::from_utf8_lossy(slice::from_raw_parts(data as *const u8, size))
|
|
}
|
|
ffi::LUA_TTABLE => format!("<table {:?}>", ffi::lua_topointer(state, index)).into(),
|
|
ffi::LUA_TFUNCTION => format!("<function {:?}>", ffi::lua_topointer(state, index)).into(),
|
|
ffi::LUA_TUSERDATA => format!("<userdata {:?}>", ffi::lua_topointer(state, index)).into(),
|
|
ffi::LUA_TTHREAD => format!("<thread {:?}>", ffi::lua_topointer(state, index)).into(),
|
|
_ => "<unknown>".into(),
|
|
}
|
|
}
|
|
|
|
unsafe fn get_destructed_userdata_metatable(state: *mut ffi::lua_State) {
|
|
ffi::lua_pushlightuserdata(
|
|
state,
|
|
&DESTRUCTED_USERDATA_METATABLE as *const u8 as *mut c_void,
|
|
);
|
|
ffi::lua_rawget(state, ffi::LUA_REGISTRYINDEX);
|
|
}
|
|
|
|
static DESTRUCTED_USERDATA_METATABLE: u8 = 0;
|
|
static ERROR_PRINT_BUFFER_KEY: u8 = 0;
|