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Combine WrappedError and WrappedPanic structs to WrappedFailure enum

This commit is contained in:
Alex Orlenko 2021-07-09 00:05:29 +01:00
parent 582b2c585f
commit 3bffe1d7c3
No known key found for this signature in database
GPG Key ID: 4C150C250863B96D
2 changed files with 159 additions and 167 deletions
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93
src/lua.rs
View File

@ -27,10 +27,10 @@ use crate::userdata::{
};
use crate::util::{
self, assert_stack, callback_error, check_stack, get_destructed_userdata_metatable,
get_gc_metatable, get_gc_userdata, get_main_state, get_userdata, get_wrapped_error,
init_error_registry, init_gc_metatable, init_userdata_metatable, pop_error, protect_lua,
push_gc_userdata, push_string, push_table, push_userdata, push_wrapped_error, rawset_field,
safe_pcall, safe_xpcall, StackGuard, WrappedError, WrappedPanic,
get_gc_metatable, get_gc_userdata, get_main_state, get_userdata, init_error_registry,
init_gc_metatable, init_userdata_metatable, pop_error, protect_lua, push_gc_userdata,
push_string, push_table, push_userdata, rawset_field, safe_pcall, safe_xpcall, StackGuard,
WrappedFailure,
};
use crate::value::{FromLua, FromLuaMulti, MultiValue, Nil, ToLua, ToLuaMulti, Value};
@ -77,9 +77,9 @@ struct ExtraData {
ref_stack_top: c_int,
ref_free: Vec<c_int>,
// Vec of preallocated WrappedError/WrappedPanic structs
// Vec of preallocated WrappedFailure enums
// Used for callback optimization
prealloc_wrapped_errors: Vec<c_int>,
prealloc_wrapped_failures: Vec<c_int>,
hook_callback: Option<HookCallback>,
}
@ -164,7 +164,7 @@ impl Drop for Lua {
unsafe {
if !self.ephemeral {
let extra = &mut *self.extra;
for index in extra.prealloc_wrapped_errors.clone() {
for index in extra.prealloc_wrapped_failures.clone() {
ffi::lua_pushnil(extra.ref_thread);
ffi::lua_replace(extra.ref_thread, index);
extra.ref_free.push(index);
@ -446,7 +446,7 @@ impl Lua {
ref_stack_size: ffi::LUA_MINSTACK - 1,
ref_stack_top: 0,
ref_free: Vec::new(),
prealloc_wrapped_errors: Vec::new(),
prealloc_wrapped_failures: Vec::new(),
hook_callback: None,
}));
@ -1558,8 +1558,8 @@ impl Lua {
self.push_ref(&ud.0);
}
Value::Error(e) => {
push_wrapped_error(self.state, e)?;
Value::Error(err) => {
push_gc_userdata(self.state, WrappedFailure::Error(err))?;
}
}
@ -1608,20 +1608,22 @@ impl Lua {
ffi::LUA_TUSERDATA => {
// We must prevent interaction with userdata types other than UserData OR a WrappedError.
// WrappedPanics are automatically resumed.
if let Some(err) = get_wrapped_error(state, -1).as_ref() {
match get_gc_userdata::<WrappedFailure>(state, -1).as_mut() {
Some(WrappedFailure::Error(err)) => {
let err = err.clone();
ffi::lua_pop(state, 1);
Value::Error(err)
} else if let Some(panic) = get_gc_userdata::<WrappedPanic>(state, -1).as_mut() {
if let Some(panic) = (*panic).0.take() {
}
Some(WrappedFailure::Panic(panic)) => {
if let Some(panic) = panic.take() {
ffi::lua_pop(state, 1);
resume_unwind(panic);
}
// Previously resumed panic?
ffi::lua_pop(state, 1);
Nil
} else {
Value::UserData(AnyUserData(self.pop_ref()))
}
_ => Value::UserData(AnyUserData(self.pop_ref())),
}
}
@ -2334,7 +2336,7 @@ impl<'lua, T: AsRef<[u8]> + ?Sized> AsChunk<'lua> for T {
}
}
// An optimized version of `callback_error` that does not allocate `WrappedError+Panic` userdata
// An optimized version of `callback_error` that does not allocate `WrappedFailure` userdata
// and instead reuses unsed and cached values from previous calls (or allocates new).
// It requires `get_extra` function to return `ExtraData` value.
unsafe fn callback_error_ext<E, F, R>(state: *mut ffi::lua_State, get_extra: E, f: F) -> R
@ -2357,59 +2359,60 @@ where
cstr!("not enough stack space for callback error handling"),
);
enum PreallocatedError {
New(*mut c_void),
enum PreallocatedFailure {
New(*mut WrappedFailure),
Cached(i32),
}
// We cannot shadow Rust errors with Lua ones, so we need to obtain pre-allocated memory
// to store a wrapped error or panic *before* we proceed.
let extra = &mut *get_extra(state);
let prealloc_err = {
match extra.prealloc_wrapped_errors.pop() {
Some(index) => PreallocatedError::Cached(index),
let prealloc_failure = {
match extra.prealloc_wrapped_failures.pop() {
Some(index) => PreallocatedFailure::Cached(index),
None => {
let size = mem::size_of::<WrappedError>().max(mem::size_of::<WrappedPanic>());
let ud = ffi::lua_newuserdata(state, size);
let ud = ffi::lua_newuserdata(state, mem::size_of::<WrappedFailure>());
ffi::lua_rotate(state, 1, 1);
PreallocatedError::New(ud)
PreallocatedFailure::New(ud as *mut WrappedFailure)
}
}
};
let mut get_prealloc_err = || match prealloc_err {
PreallocatedError::New(ud) => {
let mut get_prealloc_failure = || match prealloc_failure {
PreallocatedFailure::New(ud) => {
ffi::lua_settop(state, 1);
ud
}
PreallocatedError::Cached(index) => {
PreallocatedFailure::Cached(index) => {
ffi::lua_settop(state, 0);
ffi::lua_pushvalue(extra.ref_thread, index);
ffi::lua_xmove(extra.ref_thread, state, 1);
ffi::lua_pushnil(extra.ref_thread);
ffi::lua_replace(extra.ref_thread, index);
extra.ref_free.push(index);
ffi::lua_touserdata(state, -1)
ffi::lua_touserdata(state, -1) as *mut WrappedFailure
}
};
match catch_unwind(AssertUnwindSafe(|| f(nargs))) {
Ok(Ok(r)) => {
// Return unused WrappedError+Panic to the cache
match prealloc_err {
PreallocatedError::New(_) if extra.prealloc_wrapped_errors.len() < 16 => {
// Return unused WrappedFailure to the cache
match prealloc_failure {
PreallocatedFailure::New(_) if extra.prealloc_wrapped_failures.len() < 16 => {
ffi::lua_rotate(state, 1, -1);
ffi::lua_xmove(state, extra.ref_thread, 1);
let index = ref_stack_pop(extra);
extra.prealloc_wrapped_errors.push(index);
extra.prealloc_wrapped_failures.push(index);
}
PreallocatedError::New(_) => {
PreallocatedFailure::New(_) => {
ffi::lua_remove(state, 1);
}
PreallocatedError::Cached(index) if extra.prealloc_wrapped_errors.len() < 16 => {
extra.prealloc_wrapped_errors.push(index);
PreallocatedFailure::Cached(index)
if extra.prealloc_wrapped_failures.len() < 16 =>
{
extra.prealloc_wrapped_failures.push(index);
}
PreallocatedError::Cached(index) => {
PreallocatedFailure::Cached(index) => {
ffi::lua_pushnil(extra.ref_thread);
ffi::lua_replace(extra.ref_thread, index);
extra.ref_free.push(index);
@ -2418,9 +2421,9 @@ where
r
}
Ok(Err(err)) => {
let wrapped_error = get_prealloc_err() as *mut WrappedError;
ptr::write(wrapped_error, WrappedError(err));
get_gc_metatable::<WrappedError>(state);
let wrapped_error = get_prealloc_failure();
ptr::write(wrapped_error, WrappedFailure::Error(err));
get_gc_metatable::<WrappedFailure>(state);
ffi::lua_setmetatable(state, -2);
// Convert to CallbackError and attach traceback
@ -2432,15 +2435,17 @@ where
} else {
"<not enough stack space for traceback>".to_string()
};
let cause = Arc::new((*wrapped_error).0.clone());
(*wrapped_error).0 = Error::CallbackError { traceback, cause };
if let WrappedFailure::Error(ref mut err) = *wrapped_error {
let cause = Arc::new(err.clone());
*err = Error::CallbackError { traceback, cause };
}
ffi::lua_error(state)
}
Err(p) => {
let wrapped_panic = get_prealloc_err() as *mut WrappedPanic;
ptr::write(wrapped_panic, WrappedPanic(Some(p)));
get_gc_metatable::<WrappedPanic>(state);
let wrapped_panic = get_prealloc_failure();
ptr::write(wrapped_panic, WrappedFailure::Panic(Some(p)));
get_gc_metatable::<WrappedFailure>(state);
ffi::lua_setmetatable(state, -2);
ffi::lua_error(state)
}

107
src/util.rs
View File

@ -167,16 +167,19 @@ pub unsafe fn pop_error(state: *mut ffi::lua_State, err_code: c_int) -> Error {
"pop_error called with non-error return code"
);
if let Some(err) = get_wrapped_error(state, -1).as_ref() {
match get_gc_userdata::<WrappedFailure>(state, -1).as_mut() {
Some(WrappedFailure::Error(err)) => {
ffi::lua_pop(state, 1);
err.clone()
} else if let Some(panic) = get_gc_userdata::<WrappedPanic>(state, -1).as_mut() {
if let Some(p) = (*panic).0.take() {
}
Some(WrappedFailure::Panic(panic)) => {
if let Some(p) = panic.take() {
resume_unwind(p);
} else {
Error::PreviouslyResumedPanic
}
} else {
}
_ => {
let err_string = to_string(state, -1);
ffi::lua_pop(state, 1);
@ -204,6 +207,7 @@ pub unsafe fn pop_error(state: *mut ffi::lua_State, err_code: c_int) -> Error {
_ => mlua_panic!("unrecognized lua error code"),
}
}
}
}
// Uses 3 stack spaces
@ -480,10 +484,7 @@ where
// We cannot shadow Rust errors with Lua ones, we pre-allocate enough memory
// to store a wrapped error or panic *before* we proceed.
let ud = ffi::lua_newuserdata(
state,
mem::size_of::<WrappedError>().max(mem::size_of::<WrappedPanic>()),
);
let ud = ffi::lua_newuserdata(state, mem::size_of::<WrappedFailure>());
ffi::lua_rotate(state, 1, 1);
match catch_unwind(AssertUnwindSafe(|| f(nargs))) {
@ -494,9 +495,9 @@ where
Ok(Err(err)) => {
ffi::lua_settop(state, 1);
let wrapped_error = ud as *mut WrappedError;
ptr::write(wrapped_error, WrappedError(err));
get_gc_metatable::<WrappedError>(state);
let wrapped_error = ud as *mut WrappedFailure;
ptr::write(wrapped_error, WrappedFailure::Error(err));
get_gc_metatable::<WrappedFailure>(state);
ffi::lua_setmetatable(state, -2);
// Convert to CallbackError and attach traceback
@ -508,15 +509,17 @@ where
} else {
"<not enough stack space for traceback>".to_string()
};
let cause = Arc::new((*wrapped_error).0.clone());
(*wrapped_error).0 = Error::CallbackError { traceback, cause };
if let WrappedFailure::Error(ref mut err) = *wrapped_error {
let cause = Arc::new(err.clone());
*err = Error::CallbackError { traceback, cause };
}
ffi::lua_error(state)
}
Err(p) => {
ffi::lua_settop(state, 1);
ptr::write(ud as *mut WrappedPanic, WrappedPanic(Some(p)));
get_gc_metatable::<WrappedPanic>(state);
ptr::write(ud as *mut WrappedFailure, WrappedFailure::Panic(Some(p)));
get_gc_metatable::<WrappedFailure>(state);
ffi::lua_setmetatable(state, -2);
ffi::lua_error(state)
}
@ -530,9 +533,7 @@ pub unsafe extern "C" fn error_traceback(state: *mut ffi::lua_State) -> c_int {
return 1;
}
if get_gc_userdata::<WrappedError>(state, -1).is_null()
&& get_gc_userdata::<WrappedPanic>(state, -1).is_null()
{
if get_gc_userdata::<WrappedFailure>(state, -1).is_null() {
let s = ffi::luaL_tolstring(state, -1, ptr::null_mut());
if ffi::lua_checkstack(state, ffi::LUA_TRACEBACK_STACK) != 0 {
ffi::luaL_traceback(state, state, s, 1);
@ -558,7 +559,9 @@ pub unsafe extern "C" fn safe_pcall(state: *mut ffi::lua_State) -> c_int {
ffi::lua_insert(state, 1);
ffi::lua_gettop(state)
} else {
if !get_gc_userdata::<WrappedPanic>(state, -1).is_null() {
if let Some(WrappedFailure::Panic(_)) =
get_gc_userdata::<WrappedFailure>(state, -1).as_ref()
{
ffi::lua_error(state);
}
ffi::lua_pushboolean(state, 0);
@ -572,7 +575,9 @@ pub unsafe extern "C" fn safe_xpcall(state: *mut ffi::lua_State) -> c_int {
unsafe extern "C" fn xpcall_msgh(state: *mut ffi::lua_State) -> c_int {
ffi::luaL_checkstack(state, 2, ptr::null());
if !get_gc_userdata::<WrappedPanic>(state, -1).is_null() {
if let Some(WrappedFailure::Panic(_)) =
get_gc_userdata::<WrappedFailure>(state, -1).as_ref()
{
1
} else {
ffi::lua_pushvalue(state, ffi::lua_upvalueindex(1));
@ -600,7 +605,9 @@ pub unsafe extern "C" fn safe_xpcall(state: *mut ffi::lua_State) -> c_int {
ffi::lua_insert(state, 2);
ffi::lua_gettop(state) - 1
} else {
if !get_gc_userdata::<WrappedPanic>(state, -1).is_null() {
if let Some(WrappedFailure::Panic(_)) =
get_gc_userdata::<WrappedFailure>(state, -1).as_ref()
{
ffi::lua_error(state);
}
ffi::lua_pushboolean(state, 0);
@ -632,23 +639,6 @@ pub unsafe fn get_main_state(state: *mut ffi::lua_State) -> Option<*mut ffi::lua
}
}
// Pushes a WrappedError to the top of the stack.
// Uses 3 stack spaces and does not call 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 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 method) metatable for a type T.
// Uses 6 stack spaces and calls checkstack.
pub unsafe fn init_gc_metatable<T: Any>(
@ -697,7 +687,6 @@ pub unsafe fn get_gc_metatable<T: Any>(state: *mut ffi::lua_State) {
}
// Initialize the error, panic, and destructed userdata metatables.
// Returns address of WrappedError and WrappedPanic metatables in Lua registry.
pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
check_stack(state, 7)?;
@ -707,7 +696,8 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
callback_error(state, |_| {
check_stack(state, 3)?;
let err_buf = if let Some(error) = get_wrapped_error(state, -1).as_ref() {
let err_buf = match get_gc_userdata::<WrappedFailure>(state, -1).as_ref() {
Some(WrappedFailure::Error(error)) => {
let err_buf_key = &ERROR_PRINT_BUFFER_KEY as *const u8 as *const c_void;
ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, err_buf_key);
let err_buf = ffi::lua_touserdata(state, -1) as *mut String;
@ -726,14 +716,17 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
source0 = Some(source);
}
match (source1, source0) {
(_, Some(error0)) if error0.to_string().contains("\nstack traceback:\n") => {
(_, Some(error0))
if error0.to_string().contains("\nstack traceback:\n") =>
{
let _ = write!(&mut (*err_buf), "\ncaused by: {}", error0);
}
(Some(error1), Some(error0)) => {
let _ = write!(&mut (*err_buf), "\ncaused by: {}", error0);
let s = error1.to_string();
if let Some(traceback) = s.splitn(2, "\nstack traceback:\n").nth(1) {
let _ = write!(&mut (*err_buf), "\nstack traceback:\n{}", traceback);
let _ =
write!(&mut (*err_buf), "\nstack traceback:\n{}", traceback);
}
}
(Some(error1), None) => {
@ -742,28 +735,28 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
_ => {}
}
Ok(err_buf)
} else if let Some(panic) = get_gc_userdata::<WrappedPanic>(state, -1).as_ref() {
if let Some(ref p) = (*panic).0 {
}
Some(WrappedFailure::Panic(Some(ref panic))) => {
let err_buf_key = &ERROR_PRINT_BUFFER_KEY as *const u8 as *const c_void;
ffi::lua_rawgetp(state, ffi::LUA_REGISTRYINDEX, err_buf_key);
let err_buf = ffi::lua_touserdata(state, -1) as *mut String;
(*err_buf).clear();
ffi::lua_pop(state, 2);
if let Some(msg) = p.downcast_ref::<&str>() {
if let Some(msg) = panic.downcast_ref::<&str>() {
let _ = write!(&mut (*err_buf), "{}", msg);
} else if let Some(msg) = p.downcast_ref::<String>() {
} else if let Some(msg) = panic.downcast_ref::<String>() {
let _ = write!(&mut (*err_buf), "{}", msg);
} else {
let _ = write!(&mut (*err_buf), "<panic>");
};
Ok(err_buf)
} else {
Err(Error::PreviouslyResumedPanic)
}
} else {
Some(WrappedFailure::Panic(None)) => Err(Error::PreviouslyResumedPanic),
_ => {
// I'm not sure whether this is possible to trigger without bugs in mlua?
Err(Error::UserDataTypeMismatch)
}
}?;
push_string(state, &*err_buf)?;
@ -773,15 +766,7 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
})
}
init_gc_metatable::<WrappedError>(
state,
Some(|state| {
ffi::lua_pushcfunction(state, error_tostring);
rawset_field(state, -2, "__tostring")
}),
)?;
init_gc_metatable::<WrappedPanic>(
init_gc_metatable::<WrappedFailure>(
state,
Some(|state| {
ffi::lua_pushcfunction(state, error_tostring);
@ -856,8 +841,10 @@ pub unsafe fn init_error_registry(state: *mut ffi::lua_State) -> Result<()> {
Ok(())
}
pub(crate) struct WrappedError(pub Error);
pub(crate) struct WrappedPanic(pub Option<Box<dyn Any + Send + 'static>>);
pub(crate) enum WrappedFailure {
Error(Error),
Panic(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.