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Update docs & minor error handling code changes

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This commit is contained in:
Alex Orlenko 2021-05-11 14:18:22 +01:00
parent fe39ae09bf
commit b610a79d66
2 changed files with 20 additions and 28 deletions
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45
src/ffi/shim/shim.c
View file

@ -47,9 +47,21 @@ typedef struct {
size_t len;
} StringArg;
static void handle_wrapped_error(lua_State *L) {
if (lua_checkstack(L, LUA_TRACEBACK_STACK) != 0) {
luaL_traceback(L, L, NULL, 0);
// Convert to CallbackError and attach traceback
wrapped_error_traceback(L, -2, -1);
lua_pop(L, 1);
} else {
// Convert to CallbackError with error message as a traceback
wrapped_error_traceback(L, -1, 0);
}
}
// A wrapper around Rust function to protect from triggering longjmp in Rust.
// Rust callback expected to return -1 in case of errors or number of output
// values.
// Rust callback expected to return positive number of output values or
// -1 in case of error, -2 in case of panic.
static int lua_call_rust(lua_State *L) {
int nargs = lua_gettop(L);
@ -73,15 +85,7 @@ static int lua_call_rust(lua_State *L) {
int ret = rust_callback(L);
if (ret < 0) {
if (ret == -1 /* WrappedError */) {
if (lua_checkstack(L, LUA_TRACEBACK_STACK) != 0) {
luaL_traceback(L, L, NULL, 0);
// Convert to CallbackError and attach traceback
wrapped_error_traceback(L, -2, -1);
lua_pop(L, 1);
} else {
// Convert to CallbackError with error message as a traceback
wrapped_error_traceback(L, -1, 0);
}
handle_wrapped_error(L);
}
lua_error(L);
}
@ -96,15 +100,7 @@ void lua_call_mlua_hook_proc(lua_State *L, lua_Debug *ar) {
int ret = mlua_hook_proc(L, ar);
if (ret < 0) {
if (ret == -1 /* WrappedError */) {
if (lua_checkstack(L, LUA_TRACEBACK_STACK) != 0) {
luaL_traceback(L, L, NULL, 0);
// Convert to CallbackError and attach traceback
wrapped_error_traceback(L, -2, -1);
lua_pop(L, 1);
} else {
// Convert to CallbackError with error message as a traceback
wrapped_error_traceback(L, -1, 0);
}
handle_wrapped_error(L);
}
lua_error(L);
}
@ -419,13 +415,10 @@ int is_wrapped_struct(lua_State *state, int index, const void *key) {
return res;
}
// Takes an error at the top of the stack, and if it is a WrappedError, converts
// it to an Error::CallbackError with a traceback, if it is some lua type,
// prints the error along with a traceback, and if it is a WrappedPanic, does
// Takes an error at the top of the stack and converts Lua errors into a string
// with attached traceback. If the error is a WrappedError or WrappedPanic, does
// not modify it. This function does its best to avoid triggering another error
// and shadowing previous rust errors, but it may trigger Lua errors that shadow
// rust errors under certain memory conditions. This function ensures that such
// behavior will *never* occur with a rust panic, however.
// and shadowing previous rust errors.
int error_traceback(lua_State *state) {
if (lua_checkstack(state, 2) == 0) {
// If we don't have enough stack space to even check the error type, do

3
src/util.rs
View file

@ -331,8 +331,7 @@ where
// A part of the C shim for errors handling.
// Receives indexes of error and traceback (optional) in the stack.
// Depending on `convert_to_callback_error` flag attaches traceback to the error or
// converts error into a `CallbackError` (using previously attached traceback).
// Converts error into a `CallbackError` and attaches the traceback provided.
#[no_mangle]
pub unsafe extern "C" fn wrapped_error_traceback(
state: *mut ffi::lua_State,