michael/mlua
michael
/
mlua
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Reduce error_guard code to as little as possible 

Also ensure that on error in error_guard the stack is in a predictable place.
This commit is contained in:
kyren 2017-07-23 02:08:32 -04:00
parent 36134e6373
commit 2bd7a2ee8c
3 changed files with 67 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

89
src/lua.rs
View File

@ -223,12 +223,13 @@ impl<'lua> LuaTable<'lua> {
let key = key.to_lua(lua)?; let key = key.to_lua(lua)?;
let value = value.to_lua(lua)?; let value = value.to_lua(lua)?;
unsafe { unsafe {
check_stack(lua.state, 3); check_stack(lua.state, 5);
lua.push_ref(lua.state, &self.0); lua.push_ref(lua.state, &self.0);
lua.push_value(lua.state, key); lua.push_value(lua.state, key);
lua.push_value(lua.state, value); lua.push_value(lua.state, value);
error_guard(lua.state, 3, 0, |state| { error_guard(lua.state, 3, |state| {
ffi::lua_settable(state, -3); ffi::lua_settable(state, -3);
ffi::lua_pop(state, 1);
Ok(()) Ok(())
}) })
} }
@ -243,15 +244,15 @@ impl<'lua> LuaTable<'lua> {
let lua = self.0.lua; let lua = self.0.lua;
let key = key.to_lua(lua)?; let key = key.to_lua(lua)?;
unsafe { unsafe {
check_stack(lua.state, 2); check_stack(lua.state, 4);
lua.push_ref(lua.state, &self.0); lua.push_ref(lua.state, &self.0);
lua.push_value(lua.state, key.to_lua(lua)?); lua.push_value(lua.state, key.to_lua(lua)?);
let res = error_guard(lua.state, 2, 0, |state| { error_guard(lua.state, 2, |state| {
ffi::lua_gettable(state, -2); ffi::lua_gettable(state, -2);
let res = lua.pop_value(state); Ok(())
ffi::lua_pop(state, 1);
Ok(res)
})?; })?;
let res = lua.pop_value(lua.state);
ffi::lua_pop(lua.state, 1);
V::from_lua(res, lua) V::from_lua(res, lua)
} }
} }
@ -261,15 +262,16 @@ impl<'lua> LuaTable<'lua> {
let lua = self.0.lua; let lua = self.0.lua;
let key = key.to_lua(lua)?; let key = key.to_lua(lua)?;
unsafe { unsafe {
check_stack(lua.state, 2); check_stack(lua.state, 4);
lua.push_ref(lua.state, &self.0); lua.push_ref(lua.state, &self.0);
lua.push_value(lua.state, key); lua.push_value(lua.state, key);
error_guard(lua.state, 2, 0, |state| { error_guard(lua.state, 2, |state| {
ffi::lua_gettable(state, -2); ffi::lua_gettable(state, -2);
let has = ffi::lua_isnil(state, -1) == 0; Ok(())
ffi::lua_pop(state, 2); })?;
let has = ffi::lua_isnil(lua.state, -1) == 0;
ffi::lua_pop(lua.state, 2);
Ok(has) Ok(has)
})
} }
} }
@ -311,10 +313,12 @@ impl<'lua> LuaTable<'lua> {
pub fn len(&self) -> LuaResult<LuaInteger> { pub fn len(&self) -> LuaResult<LuaInteger> {
let lua = self.0.lua; let lua = self.0.lua;
unsafe { unsafe {
error_guard(lua.state, 0, 0, |state| { check_stack(lua.state, 3);
check_stack(state, 1); lua.push_ref(lua.state, &self.0);
lua.push_ref(state, &self.0); error_guard(lua.state, 1, |state| {
Ok(ffi::luaL_len(state, -1)) let len = ffi::luaL_len(state, -1);
ffi::lua_pop(state, 1);
Ok(len)
}) })
} }
} }
@ -381,31 +385,29 @@ where
let lua = self.table.lua; let lua = self.table.lua;
unsafe { unsafe {
check_stack(lua.state, 4); check_stack(lua.state, 6);
lua.push_ref(lua.state, &self.table); lua.push_ref(lua.state, &self.table);
lua.push_ref(lua.state, &next_key); lua.push_ref(lua.state, &next_key);
match error_guard(lua.state, 2, 0, |state| if ffi::lua_next(state, -2) != 0 { match error_guard(lua.state, 2, |state| Ok(ffi::lua_next(state, -2) != 0)) {
ffi::lua_pushvalue(state, -2); Ok(true) => {
let key = lua.pop_value(state); ffi::lua_pushvalue(lua.state, -2);
let value = lua.pop_value(state); let key = lua.pop_value(lua.state);
let next_key = lua.pop_ref(lua.state); let value = lua.pop_value(lua.state);
self.next_key = Some(lua.pop_ref(lua.state));
ffi::lua_pop(lua.state, 1); ffi::lua_pop(lua.state, 1);
Ok(Some((key, value, next_key)))
} else {
ffi::lua_pop(lua.state, 1);
Ok(None)
}) {
Ok(Some((key, value, next_key))) => {
self.next_key = Some(next_key);
Some((|| { Some((|| {
let key = K::from_lua(key, lua)?; let key = K::from_lua(key, lua)?;
let value = V::from_lua(value, lua)?; let value = V::from_lua(value, lua)?;
Ok((key, value)) Ok((key, value))
})()) })())
} }
Ok(None) => None, Ok(false) => {
ffi::lua_pop(lua.state, 1);
None
}
Err(e) => Some(Err(e)), Err(e) => Some(Err(e)),
} }
} }
@ -436,27 +438,20 @@ where
let lua = self.table.lua; let lua = self.table.lua;
unsafe { unsafe {
check_stack(lua.state, 2); check_stack(lua.state, 4);
lua.push_ref(lua.state, &self.table); lua.push_ref(lua.state, &self.table);
match error_guard( match error_guard(lua.state, 1, |state| Ok(ffi::lua_geti(state, -1, index) != ffi::LUA_TNIL)) {
lua.state, Ok(true) => {
1, let value = lua.pop_value(lua.state);
0, ffi::lua_pop(lua.state, 1);
|state| if ffi::lua_geti(state, -1, index) != ffi::LUA_TNIL {
let value = lua.pop_value(state);
ffi::lua_pop(state, 1);
Ok(Some(value))
} else {
ffi::lua_pop(state, 2);
Ok(None)
},
) {
Ok(Some(r)) => {
self.index = Some(index + 1); self.index = Some(index + 1);
Some(V::from_lua(r, lua)) Some(V::from_lua(value, lua))
} }
Ok(None) => None, Ok(false) => {
ffi::lua_pop(lua.state, 2);
None
},
Err(e) => Some(Err(e)), Err(e) => Some(Err(e)),
} }
} }

8
src/tests.rs
View File

@ -810,16 +810,10 @@ fn test_expired_userdata() {
id: u8, id: u8,
} }
impl Drop for Userdata {
fn drop(&mut self) {
println!("dropping {}", self.id);
}
}
impl LuaUserDataType for Userdata { impl LuaUserDataType for Userdata {
fn add_methods(methods: &mut LuaUserDataMethods<Self>) { fn add_methods(methods: &mut LuaUserDataMethods<Self>) {
methods.add_method("access", |lua, this, _| { methods.add_method("access", |lua, this, _| {
println!("accessing userdata {}", this.id); assert!(this.id == 123);
lua.pack(()) lua.pack(())
}); });
} }

30
src/util.rs
View File

@ -20,7 +20,7 @@ macro_rules! cstr {
macro_rules! lua_panic { macro_rules! lua_panic {
($state:expr) => { ($state:expr) => {
{ {
$crate::ffi::lua_settop($state, 0); $crate::ffi::lua_settor($state, 0);
panic!("rlua internal error"); panic!("rlua internal error");
} }
}; };
@ -151,16 +151,15 @@ where
res res
} }
// Call the given rust function in a protected lua context, similar to pcall. // Call the given rust function in a protected lua context, similar to pcall. The stack given to
// The stack given to the protected function is a separate protected stack. This // the protected function is a separate protected stack. This catches all calls to lua_error, but
// catches all calls to lua_error, but ffi functions that can call lua_error are // ffi functions that can call lua_error are still longjmps, and have all the same dangers as
// still longjmps, and have all the same dangers as longjmps, so extreme care // longjmps, so extreme care must still be taken in code that uses this function. Does not call
// must still be taken in code that uses this function. Does not call // lua_checkstack, and uses 2 extra stack spaces. On error, the stack position is set to just below
// lua_checkstack, and uses 2 extra stack spaces. // the given arguments.
pub unsafe fn error_guard<F, R>( pub unsafe fn error_guard<F, R>(
state: *mut ffi::lua_State, state: *mut ffi::lua_State,
nargs: c_int, nargs: c_int,
nresults: c_int,
func: F, func: F,
) -> LuaResult<R> ) -> LuaResult<R>
where where
@ -179,7 +178,6 @@ where
unsafe fn cpcall<F>( unsafe fn cpcall<F>(
state: *mut ffi::lua_State, state: *mut ffi::lua_State,
nargs: c_int, nargs: c_int,
nresults: c_int,
mut func: F, mut func: F,
) -> LuaResult<()> ) -> LuaResult<()>
where where
@ -189,16 +187,22 @@ where
ffi::lua_insert(state, -(nargs + 1)); ffi::lua_insert(state, -(nargs + 1));
ffi::lua_pushlightuserdata(state, &mut func as *mut F as *mut c_void); ffi::lua_pushlightuserdata(state, &mut func as *mut F as *mut c_void);
mem::forget(func); mem::forget(func);
handle_error(state, pcall_with_traceback(state, nargs + 1, nresults)) handle_error(state, pcall_with_traceback(state, nargs + 1, ffi::LUA_MULTRET))
} }
let mut res = None; let mut res = None;
cpcall(state, nargs, nresults, |state| { let top = ffi::lua_gettop(state);
if let Err(err) = cpcall(state, nargs, |state| {
res = Some(callback_error(state, || func(state))); res = Some(callback_error(state, || func(state)));
ffi::lua_gettop(state) let c = ffi::lua_gettop(state);
})?; c
}) {
ffi::lua_settop(state, top - nargs);
Err(err)
} else {
Ok(res.unwrap()) Ok(res.unwrap())
} }
}
// If the return code indicates an error, pops the error off of the stack and // If the return code indicates an error, pops the error off of the stack and
// returns Err. If the error is actually a WrappedPaic, clears the current lua // returns Err. If the error is actually a WrappedPaic, clears the current lua