440 lines
13 KiB
Rust
440 lines
13 KiB
Rust
use std::marker::PhantomData;
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use std::os::raw::c_int;
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use crate::error::Result;
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use crate::ffi;
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use crate::types::{Integer, LuaRef};
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use crate::util::{assert_stack, protect_lua, protect_lua_closure, StackGuard};
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use crate::value::{FromLua, Nil, ToLua, Value};
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/// Handle to an internal Lua table.
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#[derive(Clone, Debug)]
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pub struct Table<'lua>(pub(crate) LuaRef<'lua>);
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impl<'lua> Table<'lua> {
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/// Sets a key-value pair in the table.
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///
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/// If the value is `nil`, this will effectively remove the pair.
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///
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/// This might invoke the `__newindex` metamethod. Use the [`raw_set`] method if that is not
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/// desired.
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///
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/// # Examples
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///
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/// Export a value as a global to make it usable from Lua:
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///
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/// ```
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/// # use rlua::{Lua, Result};
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/// # fn main() -> Result<()> {
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/// let lua = Lua::new();
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/// let globals = lua.globals();
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///
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/// globals.set("assertions", cfg!(debug_assertions))?;
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///
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/// lua.exec::<_, ()>(r#"
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/// if assertions == true then
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/// -- ...
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/// elseif assertions == false then
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/// -- ...
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/// else
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/// error("assertions neither on nor off?")
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/// end
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/// "#, None)?;
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/// # Ok(())
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/// # }
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/// ```
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///
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/// [`raw_set`]: #method.raw_set
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pub fn set<K: ToLua<'lua>, V: ToLua<'lua>>(&self, key: K, value: V) -> Result<()> {
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let lua = self.0.lua;
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let key = key.to_lua(lua)?;
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let value = value.to_lua(lua)?;
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unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 6);
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lua.push_ref(&self.0);
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lua.push_value(key)?;
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lua.push_value(value)?;
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unsafe extern "C" fn set_table(state: *mut ffi::lua_State) -> c_int {
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ffi::lua_settable(state, -3);
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1
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}
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protect_lua(lua.state, 3, set_table)
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}
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}
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/// Gets the value associated to `key` from the table.
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///
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/// If no value is associated to `key`, returns the `nil` value.
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///
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/// This might invoke the `__index` metamethod. Use the [`raw_get`] method if that is not
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/// desired.
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///
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/// # Examples
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///
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/// Query the version of the Lua interpreter:
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///
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/// ```
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/// # use rlua::{Lua, Result};
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/// # fn main() -> Result<()> {
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/// let lua = Lua::new();
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/// let globals = lua.globals();
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///
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/// let version: String = globals.get("_VERSION")?;
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/// println!("Lua version: {}", version);
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/// # Ok(())
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/// # }
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/// ```
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///
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/// [`raw_get`]: #method.raw_get
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pub fn get<K: ToLua<'lua>, V: FromLua<'lua>>(&self, key: K) -> Result<V> {
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let lua = self.0.lua;
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let key = key.to_lua(lua)?;
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let value = unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 5);
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lua.push_ref(&self.0);
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lua.push_value(key)?;
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unsafe extern "C" fn get_table(state: *mut ffi::lua_State) -> c_int {
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ffi::lua_gettable(state, -2);
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1
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}
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protect_lua(lua.state, 2, get_table)?;
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lua.pop_value()
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};
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V::from_lua(value, lua)
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}
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/// Checks whether the table contains a non-nil value for `key`.
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pub fn contains_key<K: ToLua<'lua>>(&self, key: K) -> Result<bool> {
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let lua = self.0.lua;
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let key = key.to_lua(lua)?;
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unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 5);
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lua.push_ref(&self.0);
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lua.push_value(key)?;
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unsafe extern "C" fn get_table(state: *mut ffi::lua_State) -> c_int {
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ffi::lua_gettable(state, -2);
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1
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}
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protect_lua(lua.state, 2, get_table)?;
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let has = ffi::lua_isnil(lua.state, -1) == 0;
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Ok(has)
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}
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}
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/// Sets a key-value pair without invoking metamethods.
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pub fn raw_set<K: ToLua<'lua>, V: ToLua<'lua>>(&self, key: K, value: V) -> Result<()> {
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let lua = self.0.lua;
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let key = key.to_lua(lua)?;
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let value = value.to_lua(lua)?;
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unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 6);
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lua.push_ref(&self.0);
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lua.push_value(key)?;
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lua.push_value(value)?;
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unsafe extern "C" fn raw_set(state: *mut ffi::lua_State) -> c_int {
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ffi::lua_rawset(state, -3);
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0
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}
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protect_lua(lua.state, 3, raw_set)?;
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Ok(())
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}
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}
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/// Gets the value associated to `key` without invoking metamethods.
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pub fn raw_get<K: ToLua<'lua>, V: FromLua<'lua>>(&self, key: K) -> Result<V> {
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let lua = self.0.lua;
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let key = key.to_lua(lua)?;
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let value = unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 3);
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lua.push_ref(&self.0);
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lua.push_value(key)?;
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ffi::lua_rawget(lua.state, -2);
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lua.pop_value()
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};
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V::from_lua(value, lua)
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}
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/// Returns the result of the Lua `#` operator.
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///
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/// This might invoke the `__len` metamethod. Use the [`raw_len`] method if that is not desired.
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///
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/// [`raw_len`]: #method.raw_len
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pub fn len(&self) -> Result<Integer> {
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let lua = self.0.lua;
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unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 4);
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lua.push_ref(&self.0);
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protect_lua_closure(lua.state, 1, 0, |state| ffi::luaL_len(state, -1))
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}
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}
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/// Returns the result of the Lua `#` operator, without invoking the `__len` metamethod.
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pub fn raw_len(&self) -> Integer {
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let lua = self.0.lua;
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unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 1);
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lua.push_ref(&self.0);
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let len = ffi::lua_rawlen(lua.state, -1);
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len as Integer
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}
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}
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/// Returns a reference to the metatable of this table, or `None` if no metatable is set.
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///
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/// Unlike the `getmetatable` Lua function, this method ignores the `__metatable` field.
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pub fn get_metatable(&self) -> Option<Table<'lua>> {
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let lua = self.0.lua;
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unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 1);
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lua.push_ref(&self.0);
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if ffi::lua_getmetatable(lua.state, -1) == 0 {
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None
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} else {
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let table = Table(lua.pop_ref());
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Some(table)
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}
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}
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}
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/// Sets or removes the metatable of this table.
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///
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/// If `metatable` is `None`, the metatable is removed (if no metatable is set, this does
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/// nothing).
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pub fn set_metatable(&self, metatable: Option<Table<'lua>>) {
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let lua = self.0.lua;
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unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 1);
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lua.push_ref(&self.0);
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if let Some(metatable) = metatable {
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lua.push_ref(&metatable.0);
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} else {
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ffi::lua_pushnil(lua.state);
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}
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ffi::lua_setmetatable(lua.state, -2);
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}
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}
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/// Consume this table and return an iterator over the pairs of the table.
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///
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/// This works like the Lua `pairs` function, but does not invoke the `__pairs` metamethod.
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///
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/// The pairs are wrapped in a [`Result`], since they are lazily converted to `K` and `V` types.
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///
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/// # Note
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///
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/// While this method consumes the `Table` object, it can not prevent code from mutating the
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/// table while the iteration is in progress. Refer to the [Lua manual] for information about
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/// the consequences of such mutation.
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///
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/// # Examples
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///
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/// Iterate over all globals:
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///
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/// ```
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/// # use rlua::{Lua, Result, Value};
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/// # fn main() -> Result<()> {
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/// let lua = Lua::new();
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/// let globals = lua.globals();
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///
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/// for pair in globals.pairs::<Value, Value>() {
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/// let (key, value) = pair?;
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/// # let _ = (key, value); // used
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/// // ...
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/// }
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/// # Ok(())
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/// # }
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/// ```
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///
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/// [`Result`]: type.Result.html
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/// [Lua manual]: http://www.lua.org/manual/5.3/manual.html#pdf-next
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pub fn pairs<K: FromLua<'lua>, V: FromLua<'lua>>(self) -> TablePairs<'lua, K, V> {
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TablePairs {
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table: self.0,
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next_key: Some(Nil),
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_phantom: PhantomData,
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}
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}
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/// Consume this table and return an iterator over all values in the sequence part of the table.
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///
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/// The iterator will yield all values `t[1]`, `t[2]`, and so on, until a `nil` value is
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/// encountered. This mirrors the behaviour of Lua's `ipairs` function and will invoke the
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/// `__index` metamethod according to the usual rules. However, the deprecated `__ipairs`
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/// metatable will not be called.
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///
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/// Just like [`pairs`], the values are wrapped in a [`Result`].
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///
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/// # Note
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///
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/// While this method consumes the `Table` object, it can not prevent code from mutating the
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/// table while the iteration is in progress. Refer to the [Lua manual] for information about
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/// the consequences of such mutation.
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///
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/// # Examples
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///
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/// ```
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/// # use rlua::{Lua, Result, Table};
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/// # fn main() -> Result<()> {
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/// let lua = Lua::new();
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/// let my_table: Table = lua.load(r#"
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/// {
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/// [1] = 4,
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/// [2] = 5,
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/// [4] = 7,
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/// key = 2
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/// }
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/// "#).eval()?;
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///
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/// let expected = [4, 5];
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/// for (&expected, got) in expected.iter().zip(my_table.sequence_values::<u32>()) {
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/// assert_eq!(expected, got?);
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/// }
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/// # Ok(())
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/// # }
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/// ```
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///
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/// [`pairs`]: #method.pairs
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/// [`Result`]: type.Result.html
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/// [Lua manual]: http://www.lua.org/manual/5.3/manual.html#pdf-next
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pub fn sequence_values<V: FromLua<'lua>>(self) -> TableSequence<'lua, V> {
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TableSequence {
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table: self.0,
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index: Some(1),
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_phantom: PhantomData,
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}
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}
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}
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/// An iterator over the pairs of a Lua table.
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///
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/// This struct is created by the [`Table::pairs`] method.
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///
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/// [`Table::pairs`]: struct.Table.html#method.pairs
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pub struct TablePairs<'lua, K, V> {
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table: LuaRef<'lua>,
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next_key: Option<Value<'lua>>,
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_phantom: PhantomData<(K, V)>,
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}
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impl<'lua, K, V> Iterator for TablePairs<'lua, K, V>
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where
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K: FromLua<'lua>,
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V: FromLua<'lua>,
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{
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type Item = Result<(K, V)>;
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fn next(&mut self) -> Option<Self::Item> {
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if let Some(next_key) = self.next_key.take() {
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let lua = self.table.lua;
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let res = (|| {
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let res = unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 6);
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lua.push_ref(&self.table);
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lua.push_value(next_key)?;
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if protect_lua_closure(lua.state, 2, ffi::LUA_MULTRET, |state| {
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ffi::lua_next(state, -2) != 0
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})? {
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ffi::lua_pushvalue(lua.state, -2);
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let key = lua.pop_value();
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let value = lua.pop_value();
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self.next_key = Some(lua.pop_value());
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Some((key, value))
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} else {
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None
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}
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};
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Ok(if let Some((key, value)) = res {
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Some((K::from_lua(key, lua)?, V::from_lua(value, lua)?))
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} else {
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None
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})
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})();
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match res {
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Ok(Some((key, value))) => Some(Ok((key, value))),
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Ok(None) => None,
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Err(e) => Some(Err(e)),
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}
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} else {
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None
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}
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}
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}
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/// An iterator over the sequence part of a Lua table.
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///
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/// This struct is created by the [`Table::sequence_values`] method.
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///
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/// [`Table::sequence_values`]: struct.Table.html#method.sequence_values
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pub struct TableSequence<'lua, V> {
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table: LuaRef<'lua>,
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index: Option<Integer>,
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_phantom: PhantomData<V>,
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}
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impl<'lua, V> Iterator for TableSequence<'lua, V>
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where
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V: FromLua<'lua>,
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{
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type Item = Result<V>;
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fn next(&mut self) -> Option<Self::Item> {
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if let Some(index) = self.index.take() {
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let lua = self.table.lua;
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let res = unsafe {
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let _sg = StackGuard::new(lua.state);
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assert_stack(lua.state, 5);
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lua.push_ref(&self.table);
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match protect_lua_closure(lua.state, 1, 1, |state| ffi::lua_geti(state, -1, index))
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{
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Ok(ffi::LUA_TNIL) => None,
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Ok(_) => {
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let value = lua.pop_value();
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self.index = Some(index + 1);
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Some(Ok(value))
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}
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Err(err) => Some(Err(err)),
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}
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};
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match res {
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Some(Ok(r)) => Some(V::from_lua(r, lua)),
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Some(Err(err)) => Some(Err(err)),
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None => None,
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}
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} else {
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None
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}
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}
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}
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