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use std::marker::PhantomData; use std::os::raw::c_int; use crate::error::{Error, Result}; use crate::ffi; use crate::function::Function; use crate::types::{Integer, LuaRef}; use crate::util::{assert_stack, protect_lua, protect_lua_closure, StackGuard}; use crate::value::{FromLua, FromLuaMulti, Nil, ToLua, ToLuaMulti, Value}; /// Handle to an internal Lua table. #[derive(Clone, Debug)] pub struct Table<'lua>(pub(crate) LuaRef<'lua>); impl<'lua> Table<'lua> { /// Sets a key-value pair in the table. /// /// If the value is `nil`, this will effectively remove the pair. /// /// This might invoke the `__newindex` metamethod. Use the [`raw_set`] method if that is not /// desired. /// /// # Examples /// /// Export a value as a global to make it usable from Lua: /// /// ``` /// # use mlua::{Lua, Result}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// let globals = lua.globals(); /// /// globals.set("assertions", cfg!(debug_assertions))?; /// /// lua.load(r#" /// if assertions == true then /// -- ... /// elseif assertions == false then /// -- ... /// else /// error("assertions neither on nor off?") /// end /// "#).exec()?; /// # Ok(()) /// # } /// ``` /// /// [`raw_set`]: #method.raw_set pub fn set<K: ToLua<'lua>, V: ToLua<'lua>>(&self, key: K, value: V) -> Result<()> { let lua = self.0.lua; let key = key.to_lua(lua)?; let value = value.to_lua(lua)?; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 6); lua.push_ref(&self.0); lua.push_value(key)?; lua.push_value(value)?; unsafe extern "C" fn set_table(state: *mut ffi::lua_State) -> c_int { ffi::lua_settable(state, -3); 1 } protect_lua(lua.state, 3, set_table) } } /// Gets the value associated to `key` from the table. /// /// If no value is associated to `key`, returns the `nil` value. /// /// This might invoke the `__index` metamethod. Use the [`raw_get`] method if that is not /// desired. /// /// # Examples /// /// Query the version of the Lua interpreter: /// /// ``` /// # use mlua::{Lua, Result}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// let globals = lua.globals(); /// /// let version: String = globals.get("_VERSION")?; /// println!("Lua version: {}", version); /// # Ok(()) /// # } /// ``` /// /// [`raw_get`]: #method.raw_get pub fn get<K: ToLua<'lua>, V: FromLua<'lua>>(&self, key: K) -> Result<V> { let lua = self.0.lua; let key = key.to_lua(lua)?; let value = unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 5); lua.push_ref(&self.0); lua.push_value(key)?; unsafe extern "C" fn get_table(state: *mut ffi::lua_State) -> c_int { ffi::lua_gettable(state, -2); 1 } protect_lua(lua.state, 2, get_table)?; lua.pop_value() }; V::from_lua(value, lua) } /// Checks whether the table contains a non-nil value for `key`. pub fn contains_key<K: ToLua<'lua>>(&self, key: K) -> Result<bool> { let lua = self.0.lua; let key = key.to_lua(lua)?; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 5); lua.push_ref(&self.0); lua.push_value(key)?; unsafe extern "C" fn get_table(state: *mut ffi::lua_State) -> c_int { ffi::lua_gettable(state, -2); 1 } protect_lua(lua.state, 2, get_table)?; let has = ffi::lua_isnil(lua.state, -1) == 0; Ok(has) } } /// Gets the function associated to `key` from the table and executes it, /// passing the table itself as the first argument. /// /// # Examples /// /// Execute the table method with name "concat": /// /// ``` /// # use mlua::{Lua, Result, Table}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// # let object = lua.create_table()?; /// # let concat = lua.create_function(|_, (_, a, b): (Table, String, String)| Ok(a + &b))?; /// # object.set("concat", concat)?; /// // simiar to: object:concat("param1", "param2") /// object.call("concat", ("param1", "param2"))?; /// # Ok(()) /// # } /// ``` /// /// This might invoke the `__index` metamethod. pub fn call<K, A, R>(&self, key: K, args: A) -> Result<R> where K: ToLua<'lua>, A: ToLuaMulti<'lua>, R: FromLuaMulti<'lua>, { let lua = self.0.lua; let mut args = args.to_lua_multi(lua)?; args.push_front(Value::Table(self.clone())); self.get::<_, Function>(key)?.call(args) } /// Compares two tables for equality. /// /// Tables are compared by reference first. /// If they are not primitively equals, then mlua will try to invoke the `__eq` metamethod. /// mlua will check `self` first for the metamethod, then `other` if not found. /// /// # Examples /// /// Compare two tables using `__eq` metamethod: /// /// ``` /// # use mlua::{Lua, Result, Table}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// let table1 = lua.create_table()?; /// table1.set(1, "value")?; /// /// let table2 = lua.create_table()?; /// table2.set(2, "value")?; /// /// let always_equals_mt = lua.create_table()?; /// always_equals_mt.set("__eq", lua.create_function(|_, (_t1, _t2): (Table, Table)| Ok(true))?)?; /// table2.set_metatable(Some(always_equals_mt)); /// /// assert!(table1.equals(&table1.clone())?); /// assert!(table1.equals(&table2)?); /// # Ok(()) /// # } /// ``` pub fn equals<T: AsRef<Self>>(&self, other: T) -> Result<bool> { let other = other.as_ref(); if self == other { return Ok(true); } // Compare using __eq metamethod if exists // First, check the self for the metamethod. // If self does not define it, then check the other table. if let Some(mt) = self.get_metatable() { if mt.contains_key("__eq")? { return mt .get::<_, Function>("__eq")? .call((self.clone(), other.clone())); } } if let Some(mt) = other.get_metatable() { if mt.contains_key("__eq")? { return mt .get::<_, Function>("__eq")? .call((self.clone(), other.clone())); } } Ok(false) } /// Sets a key-value pair without invoking metamethods. pub fn raw_set<K: ToLua<'lua>, V: ToLua<'lua>>(&self, key: K, value: V) -> Result<()> { let lua = self.0.lua; let key = key.to_lua(lua)?; let value = value.to_lua(lua)?; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 6); lua.push_ref(&self.0); lua.push_value(key)?; lua.push_value(value)?; unsafe extern "C" fn raw_set(state: *mut ffi::lua_State) -> c_int { ffi::lua_rawset(state, -3); 0 } protect_lua(lua.state, 3, raw_set)?; Ok(()) } } /// Gets the value associated to `key` without invoking metamethods. pub fn raw_get<K: ToLua<'lua>, V: FromLua<'lua>>(&self, key: K) -> Result<V> { let lua = self.0.lua; let key = key.to_lua(lua)?; let value = unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 3); lua.push_ref(&self.0); lua.push_value(key)?; ffi::lua_rawget(lua.state, -2); lua.pop_value() }; V::from_lua(value, lua) } /// Inserts element value at position idx to the table, shifting up the elements from table[idx]. /// The worst case complexity is O(n), where n is the table length. pub fn raw_insert<V: ToLua<'lua>>(&self, idx: Integer, value: V) -> Result<()> { let lua = self.0.lua; let size = self.raw_len(); if idx < 1 || idx > size + 1 { return Err(Error::RuntimeError("index out of bounds".to_string())); } let value = value.to_lua(lua)?; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 6); lua.push_ref(&self.0); lua.push_value(value)?; protect_lua_closure(lua.state, 2, 0, |state| { for i in (idx..size + 1).rev() { // table[i+1] = table[i] ffi::lua_rawgeti(state, -2, i); ffi::lua_rawseti(state, -3, i + 1); } ffi::lua_rawseti(state, -2, idx); }) } } /// Removes a key from the table. /// /// If `key` is an integer, mlua shifts down the elements from table[key+1], /// and erases element table[key]. The complexity is O(n) in worst case, /// where n is the table length. /// /// For othey key types this is equivalent to setting table[key] = nil. pub fn raw_remove<K: ToLua<'lua>>(&self, key: K) -> Result<()> { let lua = self.0.lua; let key = key.to_lua(lua)?; match key { Value::Integer(idx) => { let size = self.raw_len(); if idx < 1 || idx > size { return Err(Error::RuntimeError("index out of bounds".to_string())); } unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 6); lua.push_ref(&self.0); protect_lua_closure(lua.state, 1, 0, |state| { for i in idx..size { ffi::lua_rawgeti(state, -1, i + 1); ffi::lua_rawseti(state, -2, i); } ffi::lua_pushnil(state); ffi::lua_rawseti(state, -2, size); }) } } _ => self.raw_set(key, Nil), } } /// Returns the result of the Lua `#` operator. /// /// This might invoke the `__len` metamethod. Use the [`raw_len`] method if that is not desired. /// /// [`raw_len`]: #method.raw_len pub fn len(&self) -> Result<Integer> { let lua = self.0.lua; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 4); lua.push_ref(&self.0); protect_lua_closure(lua.state, 1, 0, |state| ffi::luaL_len(state, -1)) } } /// Returns the result of the Lua `#` operator, without invoking the `__len` metamethod. pub fn raw_len(&self) -> Integer { let lua = self.0.lua; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 1); lua.push_ref(&self.0); let len = ffi::lua_rawlen(lua.state, -1); len as Integer } } /// Returns a reference to the metatable of this table, or `None` if no metatable is set. /// /// Unlike the `getmetatable` Lua function, this method ignores the `__metatable` field. pub fn get_metatable(&self) -> Option<Table<'lua>> { let lua = self.0.lua; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 1); lua.push_ref(&self.0); if ffi::lua_getmetatable(lua.state, -1) == 0 { None } else { let table = Table(lua.pop_ref()); Some(table) } } } /// Sets or removes the metatable of this table. /// /// If `metatable` is `None`, the metatable is removed (if no metatable is set, this does /// nothing). pub fn set_metatable(&self, metatable: Option<Table<'lua>>) { let lua = self.0.lua; unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 1); lua.push_ref(&self.0); if let Some(metatable) = metatable { lua.push_ref(&metatable.0); } else { ffi::lua_pushnil(lua.state); } ffi::lua_setmetatable(lua.state, -2); } } /// Consume this table and return an iterator over the pairs of the table. /// /// This works like the Lua `pairs` function, but does not invoke the `__pairs` metamethod. /// /// The pairs are wrapped in a [`Result`], since they are lazily converted to `K` and `V` types. /// /// # Note /// /// While this method consumes the `Table` object, it can not prevent code from mutating the /// table while the iteration is in progress. Refer to the [Lua manual] for information about /// the consequences of such mutation. /// /// # Examples /// /// Iterate over all globals: /// /// ``` /// # use mlua::{Lua, Result, Value}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// let globals = lua.globals(); /// /// for pair in globals.pairs::<Value, Value>() { /// let (key, value) = pair?; /// # let _ = (key, value); // used /// // ... /// } /// # Ok(()) /// # } /// ``` /// /// [`Result`]: type.Result.html /// [Lua manual]: http://www.lua.org/manual/5.3/manual.html#pdf-next pub fn pairs<K: FromLua<'lua>, V: FromLua<'lua>>(self) -> TablePairs<'lua, K, V> { TablePairs { table: self.0, next_key: Some(Nil), _phantom: PhantomData, } } /// Consume this table and return an iterator over all values in the sequence part of the table. /// /// The iterator will yield all values `t[1]`, `t[2]`, and so on, until a `nil` value is /// encountered. This mirrors the behaviour of Lua's `ipairs` function and will invoke the /// `__index` metamethod according to the usual rules. However, the deprecated `__ipairs` /// metatable will not be called. /// /// Just like [`pairs`], the values are wrapped in a [`Result`]. /// /// # Note /// /// While this method consumes the `Table` object, it can not prevent code from mutating the /// table while the iteration is in progress. Refer to the [Lua manual] for information about /// the consequences of such mutation. /// /// # Examples /// /// ``` /// # use mlua::{Lua, Result, Table}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// let my_table: Table = lua.load(r#" /// { /// [1] = 4, /// [2] = 5, /// [4] = 7, /// key = 2 /// } /// "#).eval()?; /// /// let expected = [4, 5]; /// for (&expected, got) in expected.iter().zip(my_table.sequence_values::<u32>()) { /// assert_eq!(expected, got?); /// } /// # Ok(()) /// # } /// ``` /// /// [`pairs`]: #method.pairs /// [`Result`]: type.Result.html /// [Lua manual]: http://www.lua.org/manual/5.3/manual.html#pdf-next pub fn sequence_values<V: FromLua<'lua>>(self) -> TableSequence<'lua, V> { TableSequence { table: self.0, index: Some(1), _phantom: PhantomData, } } } impl<'lua> PartialEq for Table<'lua> { fn eq(&self, other: &Self) -> bool { self.0 == other.0 } } impl<'lua> AsRef<Table<'lua>> for Table<'lua> { #[inline] fn as_ref(&self) -> &Self { self } } /// An iterator over the pairs of a Lua table. /// /// This struct is created by the [`Table::pairs`] method. /// /// [`Table::pairs`]: struct.Table.html#method.pairs pub struct TablePairs<'lua, K, V> { table: LuaRef<'lua>, next_key: Option<Value<'lua>>, _phantom: PhantomData<(K, V)>, } impl<'lua, K, V> Iterator for TablePairs<'lua, K, V> where K: FromLua<'lua>, V: FromLua<'lua>, { type Item = Result<(K, V)>; fn next(&mut self) -> Option<Self::Item> { if let Some(next_key) = self.next_key.take() { let lua = self.table.lua; let res = (|| { let res = unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 6); lua.push_ref(&self.table); lua.push_value(next_key)?; if protect_lua_closure(lua.state, 2, ffi::LUA_MULTRET, |state| { ffi::lua_next(state, -2) != 0 })? { ffi::lua_pushvalue(lua.state, -2); let key = lua.pop_value(); let value = lua.pop_value(); self.next_key = Some(lua.pop_value()); Some((key, value)) } else { None } }; Ok(if let Some((key, value)) = res { Some((K::from_lua(key, lua)?, V::from_lua(value, lua)?)) } else { None }) })(); match res { Ok(Some((key, value))) => Some(Ok((key, value))), Ok(None) => None, Err(e) => Some(Err(e)), } } else { None } } } /// An iterator over the sequence part of a Lua table. /// /// This struct is created by the [`Table::sequence_values`] method. /// /// [`Table::sequence_values`]: struct.Table.html#method.sequence_values pub struct TableSequence<'lua, V> { table: LuaRef<'lua>, index: Option<Integer>, _phantom: PhantomData<V>, } impl<'lua, V> Iterator for TableSequence<'lua, V> where V: FromLua<'lua>, { type Item = Result<V>; fn next(&mut self) -> Option<Self::Item> { if let Some(index) = self.index.take() { let lua = self.table.lua; let res = unsafe { let _sg = StackGuard::new(lua.state); assert_stack(lua.state, 5); lua.push_ref(&self.table); match protect_lua_closure(lua.state, 1, 1, |state| ffi::lua_geti(state, -1, index)) { Ok(ffi::LUA_TNIL) => None, Ok(_) => { let value = lua.pop_value(); self.index = Some(index + 1); Some(Ok(value)) } Err(err) => Some(Err(err)), } }; match res { Some(Ok(r)) => Some(V::from_lua(r, lua)), Some(Err(err)) => Some(Err(err)), None => None, } } else { None } } }