1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966
use std::cell::{Ref, RefCell, RefMut}; use std::fmt; use std::hash::{Hash, Hasher}; use std::ops::Deref; use std::string::String as StdString; use std::sync::Arc; #[cfg(feature = "async")] use std::future::Future; #[cfg(feature = "serialize")] use { serde::ser::{self, Serialize, Serializer}, std::result::Result as StdResult, }; use crate::error::{Error, Result}; use crate::ffi; use crate::function::Function; use crate::lua::Lua; use crate::table::{Table, TablePairs}; use crate::types::{LuaRef, MaybeSend}; use crate::util::{check_stack, get_destructed_userdata_metatable, get_userdata, StackGuard}; use crate::value::{FromLua, FromLuaMulti, ToLua, ToLuaMulti, Value}; /// Kinds of metamethods that can be overridden. /// /// Currently, this mechanism does not allow overriding the `__gc` metamethod, since there is /// generally no need to do so: [`UserData`] implementors can instead just implement `Drop`. /// /// [`UserData`]: trait.UserData.html #[derive(Debug, Clone)] pub enum MetaMethod { /// The `+` operator. Add, /// The `-` operator. Sub, /// The `*` operator. Mul, /// The `/` operator. Div, /// The `%` operator. Mod, /// The `^` operator. Pow, /// The unary minus (`-`) operator. Unm, /// The floor division (//) operator. /// Requires `feature = "lua54/lua53"` #[cfg(any(feature = "lua54", feature = "lua53", doc))] IDiv, /// The bitwise AND (&) operator. /// Requires `feature = "lua54/lua53"` #[cfg(any(feature = "lua54", feature = "lua53", doc))] BAnd, /// The bitwise OR (|) operator. /// Requires `feature = "lua54/lua53"` #[cfg(any(feature = "lua54", feature = "lua53", doc))] BOr, /// The bitwise XOR (binary ~) operator. /// Requires `feature = "lua54/lua53"` #[cfg(any(feature = "lua54", feature = "lua53", doc))] BXor, /// The bitwise NOT (unary ~) operator. /// Requires `feature = "lua54/lua53"` #[cfg(any(feature = "lua54", feature = "lua53", doc))] BNot, /// The bitwise left shift (<<) operator. #[cfg(any(feature = "lua54", feature = "lua53", doc))] Shl, /// The bitwise right shift (>>) operator. #[cfg(any(feature = "lua54", feature = "lua53", doc))] Shr, /// The string concatenation operator `..`. Concat, /// The length operator `#`. Len, /// The `==` operator. Eq, /// The `<` operator. Lt, /// The `<=` operator. Le, /// Index access `obj[key]`. Index, /// Index write access `obj[key] = value`. NewIndex, /// The call "operator" `obj(arg1, args2, ...)`. Call, /// The `__tostring` metamethod. /// /// This is not an operator, but will be called by methods such as `tostring` and `print`. ToString, /// The `__pairs` metamethod. /// /// This is not an operator, but it will be called by the built-in `pairs` function. /// /// Requires `feature = "lua54/lua53/lua52"` #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52", doc))] Pairs, /// The `__close` metamethod. /// /// Executed when a variable, that marked as to-be-closed, goes out of scope. /// /// More information about to-be-closed variabled can be found in the Lua 5.4 /// [documentation][lua_doc]. /// /// Requires `feature = "lua54"` /// /// [lua_doc]: https://www.lua.org/manual/5.4/manual.html#3.3.8 #[cfg(any(feature = "lua54", doc))] Close, /// A custom metamethod. /// /// Must not be in the protected list: `__gc`, `__metatable`, `__mlua*`. Custom(StdString), } impl PartialEq for MetaMethod { fn eq(&self, other: &Self) -> bool { self.name() == other.name() } } impl Eq for MetaMethod {} impl Hash for MetaMethod { fn hash<H: Hasher>(&self, state: &mut H) { self.name().hash(state); } } impl fmt::Display for MetaMethod { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { write!(fmt, "{}", self.name()) } } impl MetaMethod { /// Returns Lua metamethod name, usually prefixed by two underscores. pub fn name(&self) -> &str { match self { MetaMethod::Add => "__add", MetaMethod::Sub => "__sub", MetaMethod::Mul => "__mul", MetaMethod::Div => "__div", MetaMethod::Mod => "__mod", MetaMethod::Pow => "__pow", MetaMethod::Unm => "__unm", #[cfg(any(feature = "lua54", feature = "lua53"))] MetaMethod::IDiv => "__idiv", #[cfg(any(feature = "lua54", feature = "lua53"))] MetaMethod::BAnd => "__band", #[cfg(any(feature = "lua54", feature = "lua53"))] MetaMethod::BOr => "__bor", #[cfg(any(feature = "lua54", feature = "lua53"))] MetaMethod::BXor => "__bxor", #[cfg(any(feature = "lua54", feature = "lua53"))] MetaMethod::BNot => "__bnot", #[cfg(any(feature = "lua54", feature = "lua53"))] MetaMethod::Shl => "__shl", #[cfg(any(feature = "lua54", feature = "lua53"))] MetaMethod::Shr => "__shr", MetaMethod::Concat => "__concat", MetaMethod::Len => "__len", MetaMethod::Eq => "__eq", MetaMethod::Lt => "__lt", MetaMethod::Le => "__le", MetaMethod::Index => "__index", MetaMethod::NewIndex => "__newindex", MetaMethod::Call => "__call", MetaMethod::ToString => "__tostring", #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))] MetaMethod::Pairs => "__pairs", #[cfg(feature = "lua54")] MetaMethod::Close => "__close", MetaMethod::Custom(ref name) => name, } } pub(crate) fn validate(self) -> Result<Self> { match self { MetaMethod::Custom(name) if name == "__gc" => Err(Error::MetaMethodRestricted(name)), MetaMethod::Custom(name) if name == "__metatable" => { Err(Error::MetaMethodRestricted(name)) } MetaMethod::Custom(name) if name.starts_with("__mlua") => { Err(Error::MetaMethodRestricted(name)) } _ => Ok(self), } } } impl From<StdString> for MetaMethod { fn from(name: StdString) -> Self { match name.as_str() { "__add" => MetaMethod::Add, "__sub" => MetaMethod::Sub, "__mul" => MetaMethod::Mul, "__div" => MetaMethod::Div, "__mod" => MetaMethod::Mod, "__pow" => MetaMethod::Pow, "__unm" => MetaMethod::Unm, #[cfg(any(feature = "lua54", feature = "lua53"))] "__idiv" => MetaMethod::IDiv, #[cfg(any(feature = "lua54", feature = "lua53"))] "__band" => MetaMethod::BAnd, #[cfg(any(feature = "lua54", feature = "lua53"))] "__bor" => MetaMethod::BOr, #[cfg(any(feature = "lua54", feature = "lua53"))] "__bxor" => MetaMethod::BXor, #[cfg(any(feature = "lua54", feature = "lua53"))] "__bnot" => MetaMethod::BNot, #[cfg(any(feature = "lua54", feature = "lua53"))] "__shl" => MetaMethod::Shl, #[cfg(any(feature = "lua54", feature = "lua53"))] "__shr" => MetaMethod::Shr, "__concat" => MetaMethod::Concat, "__len" => MetaMethod::Len, "__eq" => MetaMethod::Eq, "__lt" => MetaMethod::Lt, "__le" => MetaMethod::Le, "__index" => MetaMethod::Index, "__newindex" => MetaMethod::NewIndex, "__call" => MetaMethod::Call, "__tostring" => MetaMethod::ToString, #[cfg(any(feature = "lua54", feature = "lua53", feature = "lua52"))] "__pairs" => MetaMethod::Pairs, #[cfg(feature = "lua54")] "__close" => MetaMethod::Close, _ => MetaMethod::Custom(name), } } } impl From<&str> for MetaMethod { fn from(name: &str) -> Self { MetaMethod::from(name.to_owned()) } } /// Method registry for [`UserData`] implementors. /// /// [`UserData`]: trait.UserData.html pub trait UserDataMethods<'lua, T: UserData> { /// Add a regular method which accepts a `&T` as the first parameter. /// /// Regular methods are implemented by overriding the `__index` metamethod and returning the /// accessed method. This allows them to be used with the expected `userdata:method()` syntax. /// /// If `add_meta_method` is used to set the `__index` metamethod, the `__index` metamethod will /// be used as a fall-back if no regular method is found. fn add_method<S, A, R, M>(&mut self, name: &S, method: M) where S: AsRef<[u8]> + ?Sized, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, M: 'static + MaybeSend + Fn(&'lua Lua, &T, A) -> Result<R>; /// Add a regular method which accepts a `&mut T` as the first parameter. /// /// Refer to [`add_method`] for more information about the implementation. /// /// [`add_method`]: #method.add_method fn add_method_mut<S, A, R, M>(&mut self, name: &S, method: M) where S: AsRef<[u8]> + ?Sized, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, M: 'static + MaybeSend + FnMut(&'lua Lua, &mut T, A) -> Result<R>; /// Add an async method which accepts a `T` as the first parameter and returns Future. /// The passed `T` is cloned from the original value. /// /// Refer to [`add_method`] for more information about the implementation. /// /// Requires `feature = "async"` /// /// [`add_method`]: #method.add_method #[cfg(feature = "async")] #[cfg_attr(docsrs, doc(cfg(feature = "async")))] fn add_async_method<S, A, R, M, MR>(&mut self, name: &S, method: M) where T: Clone, S: AsRef<[u8]> + ?Sized, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, M: 'static + MaybeSend + Fn(&'lua Lua, T, A) -> MR, MR: 'lua + Future<Output = Result<R>>; /// Add a regular method as a function which accepts generic arguments, the first argument will /// be a [`AnyUserData`] of type `T` if the method is called with Lua method syntax: /// `my_userdata:my_method(arg1, arg2)`, or it is passed in as the first argument: /// `my_userdata.my_method(my_userdata, arg1, arg2)`. /// /// Prefer to use [`add_method`] or [`add_method_mut`] as they are easier to use. /// /// [`AnyUserData`]: struct.AnyUserData.html /// [`add_method`]: #method.add_method /// [`add_method_mut`]: #method.add_method_mut fn add_function<S, A, R, F>(&mut self, name: &S, function: F) where S: AsRef<[u8]> + ?Sized, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>; /// Add a regular method as a mutable function which accepts generic arguments. /// /// This is a version of [`add_function`] that accepts a FnMut argument. /// /// [`add_function`]: #method.add_function fn add_function_mut<S, A, R, F>(&mut self, name: &S, function: F) where S: AsRef<[u8]> + ?Sized, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, F: 'static + MaybeSend + FnMut(&'lua Lua, A) -> Result<R>; /// Add a regular method as an async function which accepts generic arguments /// and returns Future. /// /// This is an async version of [`add_function`]. /// /// Requires `feature = "async"` /// /// [`add_function`]: #method.add_function #[cfg(feature = "async")] #[cfg_attr(docsrs, doc(cfg(feature = "async")))] fn add_async_function<S, A, R, F, FR>(&mut self, name: &S, function: F) where T: Clone, S: AsRef<[u8]> + ?Sized, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, F: 'static + MaybeSend + Fn(&'lua Lua, A) -> FR, FR: 'lua + Future<Output = Result<R>>; /// Add a metamethod which accepts a `&T` as the first parameter. /// /// # Note /// /// This can cause an error with certain binary metamethods that can trigger if only the right /// side has a metatable. To prevent this, use [`add_meta_function`]. /// /// [`add_meta_function`]: #method.add_meta_function fn add_meta_method<S, A, R, M>(&mut self, meta: S, method: M) where S: Into<MetaMethod>, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, M: 'static + MaybeSend + Fn(&'lua Lua, &T, A) -> Result<R>; /// Add a metamethod as a function which accepts a `&mut T` as the first parameter. /// /// # Note /// /// This can cause an error with certain binary metamethods that can trigger if only the right /// side has a metatable. To prevent this, use [`add_meta_function`]. /// /// [`add_meta_function`]: #method.add_meta_function fn add_meta_method_mut<S, A, R, M>(&mut self, meta: S, method: M) where S: Into<MetaMethod>, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, M: 'static + MaybeSend + FnMut(&'lua Lua, &mut T, A) -> Result<R>; /// Add a metamethod which accepts generic arguments. /// /// Metamethods for binary operators can be triggered if either the left or right argument to /// the binary operator has a metatable, so the first argument here is not necessarily a /// userdata of type `T`. fn add_meta_function<S, A, R, F>(&mut self, meta: S, function: F) where S: Into<MetaMethod>, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, F: 'static + MaybeSend + Fn(&'lua Lua, A) -> Result<R>; /// Add a metamethod as a mutable function which accepts generic arguments. /// /// This is a version of [`add_meta_function`] that accepts a FnMut argument. /// /// [`add_meta_function`]: #method.add_meta_function fn add_meta_function_mut<S, A, R, F>(&mut self, meta: S, function: F) where S: Into<MetaMethod>, A: FromLuaMulti<'lua>, R: ToLuaMulti<'lua>, F: 'static + MaybeSend + FnMut(&'lua Lua, A) -> Result<R>; } /// Field registry for [`UserData`] implementors. /// /// [`UserData`]: trait.UserData.html pub trait UserDataFields<'lua, T: UserData> { /// Add a regular field getter as a method which accepts a `&T` as the parameter. /// /// Regular field getters are implemented by overriding the `__index` metamethod and returning the /// accessed field. This allows them to be used with the expected `userdata.field` syntax. /// /// If `add_meta_method` is used to set the `__index` metamethod, the `__index` metamethod will /// be used as a fall-back if no regular field or method are found. fn add_field_method_get<S, R, M>(&mut self, name: &S, method: M) where S: AsRef<[u8]> + ?Sized, R: ToLua<'lua>, M: 'static + MaybeSend + Fn(&'lua Lua, &T) -> Result<R>; /// Add a regular field setter as a method which accepts a `&mut T` as the first parameter. /// /// Regular field setters are implemented by overriding the `__newindex` metamethod and setting the /// accessed field. This allows them to be used with the expected `userdata.field = value` syntax. /// /// If `add_meta_method` is used to set the `__newindex` metamethod, the `__newindex` metamethod will /// be used as a fall-back if no regular field is found. fn add_field_method_set<S, A, M>(&mut self, name: &S, method: M) where S: AsRef<[u8]> + ?Sized, A: FromLua<'lua>, M: 'static + MaybeSend + FnMut(&'lua Lua, &mut T, A) -> Result<()>; /// Add a regular field getter as a function which accepts a generic [`AnyUserData`] of type `T` /// argument. /// /// Prefer to use [`add_field_method_get`] as it is easier to use. /// /// [`AnyUserData`]: struct.AnyUserData.html /// [`add_field_method_get`]: #method.add_field_method_get fn add_field_function_get<S, R, F>(&mut self, name: &S, function: F) where S: AsRef<[u8]> + ?Sized, R: ToLua<'lua>, F: 'static + MaybeSend + Fn(&'lua Lua, AnyUserData<'lua>) -> Result<R>; /// Add a regular field setter as a function which accepts a generic [`AnyUserData`] of type `T` /// first argument. /// /// Prefer to use [`add_field_method_set`] as it is easier to use. /// /// [`AnyUserData`]: struct.AnyUserData.html /// [`add_field_method_set`]: #method.add_field_method_set fn add_field_function_set<S, A, F>(&mut self, name: &S, function: F) where S: AsRef<[u8]> + ?Sized, A: FromLua<'lua>, F: 'static + MaybeSend + FnMut(&'lua Lua, AnyUserData<'lua>, A) -> Result<()>; /// Add a metamethod value computed from `f`. /// /// This will initialize the metamethod value from `f` on `UserData` creation. /// /// # Note /// /// `mlua` will trigger an error on an attempt to define a protected metamethod, /// like `__gc` or `__metatable`. fn add_meta_field_with<S, R, F>(&mut self, meta: S, f: F) where S: Into<MetaMethod>, F: 'static + MaybeSend + Fn(&'lua Lua) -> Result<R>, R: ToLua<'lua>; } /// Trait for custom userdata types. /// /// By implementing this trait, a struct becomes eligible for use inside Lua code. Implementations /// of [`ToLua`] and [`FromLua`] are automatically provided. /// /// # Examples /// /// ``` /// # use mlua::{Lua, Result, UserData}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// struct MyUserData(i32); /// /// impl UserData for MyUserData {} /// /// // `MyUserData` now implements `ToLua`: /// lua.globals().set("myobject", MyUserData(123))?; /// /// lua.load("assert(type(myobject) == 'userdata')").exec()?; /// # Ok(()) /// # } /// ``` /// /// Custom fields, methods and operators can be provided by implementing `add_fields` or `add_methods` /// (refer to [`UserDataFields`] and [`UserDataMethods`] for more information): /// /// ``` /// # use mlua::{Lua, MetaMethod, Result, UserData, UserDataFields, UserDataMethods}; /// # fn main() -> Result<()> { /// # let lua = Lua::new(); /// struct MyUserData(i32); /// /// impl UserData for MyUserData { /// fn add_fields<'lua, F: UserDataFields<'lua, Self>>(fields: &mut F) { /// fields.add_field_method_get("val", |_, this| Ok(this.0)); /// } /// /// fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(methods: &mut M) { /// methods.add_method_mut("add", |_, this, value: i32| { /// this.0 += value; /// Ok(()) /// }); /// /// methods.add_meta_method(MetaMethod::Add, |_, this, value: i32| { /// Ok(this.0 + value) /// }); /// } /// } /// /// lua.globals().set("myobject", MyUserData(123))?; /// /// lua.load(r#" /// assert(myobject.val == 123) /// myobject:add(7) /// assert(myobject.val == 130) /// assert(myobject + 10 == 140) /// "#).exec()?; /// # Ok(()) /// # } /// ``` /// /// [`ToLua`]: trait.ToLua.html /// [`FromLua`]: trait.FromLua.html /// [`UserDataFields`]: trait.UserDataFields.html /// [`UserDataMethods`]: trait.UserDataMethods.html pub trait UserData: Sized { /// Adds custom fields specific to this userdata. fn add_fields<'lua, F: UserDataFields<'lua, Self>>(_fields: &mut F) {} /// Adds custom methods and operators specific to this userdata. fn add_methods<'lua, M: UserDataMethods<'lua, Self>>(_methods: &mut M) {} } // Wraps UserData in a way to always implement `serde::Serialize` trait. pub(crate) enum UserDataCell<T> { Arc(Arc<RefCell<UserDataWrapped<T>>>), Plain(RefCell<UserDataWrapped<T>>), } impl<T> UserDataCell<T> { pub(crate) fn new(data: T) -> Self { UserDataCell::Plain(RefCell::new(UserDataWrapped { data: Box::into_raw(Box::new(data)), #[cfg(feature = "serialize")] ser: Box::into_raw(Box::new(UserDataSerializeError)), })) } pub(crate) fn new_arc(data: T) -> Self { UserDataCell::Arc(Arc::new(RefCell::new(UserDataWrapped { data: Box::into_raw(Box::new(data)), #[cfg(feature = "serialize")] ser: Box::into_raw(Box::new(UserDataSerializeError)), }))) } #[cfg(feature = "serialize")] pub(crate) fn new_ser(data: T) -> Self where T: 'static + Serialize, { let data_raw = Box::into_raw(Box::new(data)); UserDataCell::Plain(RefCell::new(UserDataWrapped { data: data_raw, ser: data_raw, })) } } impl<T> Deref for UserDataCell<T> { type Target = RefCell<UserDataWrapped<T>>; fn deref(&self) -> &Self::Target { match self { UserDataCell::Arc(t) => &*t, UserDataCell::Plain(t) => &*t, } } } impl<T> Clone for UserDataCell<T> { fn clone(&self) -> Self { match self { UserDataCell::Arc(t) => UserDataCell::Arc(t.clone()), UserDataCell::Plain(_) => mlua_panic!("cannot clone non-arc userdata"), } } } pub(crate) struct UserDataWrapped<T> { pub(crate) data: *mut T, #[cfg(feature = "serialize")] ser: *mut dyn erased_serde::Serialize, } impl<T> Drop for UserDataWrapped<T> { fn drop(&mut self) { unsafe { drop(Box::from_raw(self.data)); #[cfg(feature = "serialize")] if self.data as *mut () != self.ser as *mut () { drop(Box::from_raw(self.ser)); } } } } impl<T> AsRef<T> for UserDataWrapped<T> { fn as_ref(&self) -> &T { unsafe { &*self.data } } } impl<T> AsMut<T> for UserDataWrapped<T> { fn as_mut(&mut self) -> &mut T { unsafe { &mut *self.data } } } #[cfg(feature = "serialize")] pub(crate) struct UserDataSerializeError; #[cfg(feature = "serialize")] impl Serialize for UserDataSerializeError { fn serialize<S>(&self, _serializer: S) -> StdResult<S::Ok, S::Error> where S: Serializer, { Err(ser::Error::custom("cannot serialize <userdata>")) } } /// Handle to an internal Lua userdata for any type that implements [`UserData`]. /// /// Similar to `std::any::Any`, this provides an interface for dynamic type checking via the [`is`] /// and [`borrow`] methods. /// /// Internally, instances are stored in a `RefCell`, to best match the mutable semantics of the Lua /// language. /// /// # Note /// /// This API should only be used when necessary. Implementing [`UserData`] already allows defining /// methods which check the type and acquire a borrow behind the scenes. /// /// [`UserData`]: trait.UserData.html /// [`is`]: #method.is /// [`borrow`]: #method.borrow #[derive(Clone, Debug)] pub struct AnyUserData<'lua>(pub(crate) LuaRef<'lua>); impl<'lua> AnyUserData<'lua> { /// Checks whether the type of this userdata is `T`. pub fn is<T: 'static + UserData>(&self) -> bool { match self.inspect(|_: &UserDataCell<T>| Ok(())) { Ok(()) => true, Err(Error::UserDataTypeMismatch) => false, Err(_) => unreachable!(), } } /// Borrow this userdata immutably if it is of type `T`. /// /// # Errors /// /// Returns a `UserDataBorrowError` if the userdata is already mutably borrowed. Returns a /// `UserDataTypeMismatch` if the userdata is not of type `T`. pub fn borrow<T: 'static + UserData>(&self) -> Result<Ref<T>> { self.inspect(|cell| { let cell_ref = cell.try_borrow().map_err(|_| Error::UserDataBorrowError)?; Ok(Ref::map(cell_ref, |x| unsafe { &*x.data })) }) } /// Borrow this userdata mutably if it is of type `T`. /// /// # Errors /// /// Returns a `UserDataBorrowMutError` if the userdata is already borrowed. Returns a /// `UserDataTypeMismatch` if the userdata is not of type `T`. pub fn borrow_mut<T: 'static + UserData>(&self) -> Result<RefMut<T>> { self.inspect(|cell| { let cell_ref = cell .try_borrow_mut() .map_err(|_| Error::UserDataBorrowMutError)?; Ok(RefMut::map(cell_ref, |x| unsafe { &mut *x.data })) }) } /// Sets an associated value to this `AnyUserData`. /// /// The value may be any Lua value whatsoever, and can be retrieved with [`get_user_value`]. /// As Lua < 5.3 allows to store only tables, the value will be stored in a table at index 1. /// /// [`get_user_value`]: #method.get_user_value pub fn set_user_value<V: ToLua<'lua>>(&self, v: V) -> Result<()> { let lua = self.0.lua; #[cfg(any(feature = "lua52", feature = "lua51", feature = "luajit"))] let v = { // Lua <= 5.2 allows to store only a table. Then we will wrap the value. let t = lua.create_table_with_capacity(1, 0)?; t.raw_set(1, v)?; Value::Table(t) }; #[cfg(any(feature = "lua54", feature = "lua53"))] let v = v.to_lua(lua)?; unsafe { let _sg = StackGuard::new(lua.state); check_stack(lua.state, 3)?; lua.push_userdata_ref(&self.0)?; lua.push_value(v)?; ffi::lua_setuservalue(lua.state, -2); Ok(()) } } /// Returns an associated value set by [`set_user_value`]. /// /// For Lua < 5.3 the value will be automatically extracted from the table wrapper from index 1. /// /// [`set_user_value`]: #method.set_user_value pub fn get_user_value<V: FromLua<'lua>>(&self) -> Result<V> { let lua = self.0.lua; let res = unsafe { let _sg = StackGuard::new(lua.state); check_stack(lua.state, 3)?; lua.push_userdata_ref(&self.0)?; ffi::lua_getuservalue(lua.state, -1); lua.pop_value() }; #[cfg(any(feature = "lua52", feature = "lua51", feature = "luajit"))] return match <Option<Table>>::from_lua(res, lua)? { Some(t) => t.get(1), None => V::from_lua(Value::Nil, lua), }; #[cfg(any(feature = "lua54", feature = "lua53"))] V::from_lua(res, lua) } /// Returns a metatable of this `UserData`. /// /// Returned [`UserDataMetatable`] object wraps the original metatable and /// provides safe access to it methods. /// /// For `T: UserData + 'static` returned metatable is shared among all instances of type `T`. /// /// [`UserDataMetatable`]: struct.UserDataMetatable.html pub fn get_metatable(&self) -> Result<UserDataMetatable<'lua>> { self.get_raw_metatable().map(UserDataMetatable) } /// Checks for a metamethod in this `AnyUserData`. /// /// This function is deprecated and will be removed in v0.7. /// Please use [`get_metatable`] function instead. /// /// [`get_metatable`]: #method.get_metatable #[deprecated( since = "0.6.0", note = "Please use the get_metatable function instead" )] pub fn has_metamethod(&self, method: MetaMethod) -> Result<bool> { match self.get_raw_metatable() { Ok(mt) => { let name = self.0.lua.create_string(method.validate()?.name())?; if let Value::Nil = mt.raw_get(name)? { Ok(false) } else { Ok(true) } } Err(Error::UserDataTypeMismatch) => Ok(false), Err(e) => Err(e), } } fn get_raw_metatable(&self) -> Result<Table<'lua>> { unsafe { let lua = self.0.lua; let _sg = StackGuard::new(lua.state); check_stack(lua.state, 3)?; lua.push_userdata_ref(&self.0)?; ffi::lua_getmetatable(lua.state, -1); // Checked that non-empty on the previous call Ok(Table(lua.pop_ref())) } } pub(crate) fn equals<T: AsRef<Self>>(&self, other: T) -> Result<bool> { let other = other.as_ref(); // Uses lua_rawequal() under the hood if self == other { return Ok(true); } let mt = self.get_raw_metatable()?; if mt != other.get_raw_metatable()? { return Ok(false); } if mt.contains_key("__eq")? { return mt .get::<_, Function>("__eq")? .call((self.clone(), other.clone())); } Ok(false) } fn inspect<'a, T, R, F>(&'a self, func: F) -> Result<R> where T: 'static + UserData, F: FnOnce(&'a UserDataCell<T>) -> Result<R>, { let lua = self.0.lua; unsafe { let _sg = StackGuard::new(lua.state); check_stack(lua.state, 3)?; lua.push_ref(&self.0); if ffi::lua_getmetatable(lua.state, -1) == 0 { return Err(Error::UserDataTypeMismatch); } lua.push_userdata_metatable::<T>()?; if ffi::lua_rawequal(lua.state, -1, -2) == 0 { // Maybe UserData destructed? ffi::lua_pop(lua.state, 1); get_destructed_userdata_metatable(lua.state); if ffi::lua_rawequal(lua.state, -1, -2) == 1 { Err(Error::UserDataDestructed) } else { Err(Error::UserDataTypeMismatch) } } else { func(&*get_userdata::<UserDataCell<T>>(lua.state, -3)) } } } } impl<'lua> PartialEq for AnyUserData<'lua> { fn eq(&self, other: &Self) -> bool { self.0 == other.0 } } impl<'lua> AsRef<AnyUserData<'lua>> for AnyUserData<'lua> { #[inline] fn as_ref(&self) -> &Self { self } } /// Handle to a `UserData` metatable. #[derive(Clone, Debug)] pub struct UserDataMetatable<'lua>(pub(crate) Table<'lua>); impl<'lua> UserDataMetatable<'lua> { /// Gets the value associated to `key` from the metatable. /// /// If no value is associated to `key`, returns the `Nil` value. /// Access to restricted metamethods such as `__gc` or `__metatable` will cause an error. pub fn get<K: Into<MetaMethod>, V: FromLua<'lua>>(&self, key: K) -> Result<V> { self.0.raw_get(key.into().validate()?.name()) } /// Sets a key-value pair in the metatable. /// /// If the value is `Nil`, this will effectively remove the `key`. /// Access to restricted metamethods such as `__gc` or `__metatable` will cause an error. /// Setting `__index` or `__newindex` metamethods is also restricted because their values are cached /// for `mlua` internal usage. pub fn set<K: Into<MetaMethod>, V: ToLua<'lua>>(&self, key: K, value: V) -> Result<()> { let key = key.into().validate()?; // `__index` and `__newindex` cannot be changed in runtime, because values are cached if key == MetaMethod::Index || key == MetaMethod::NewIndex { return Err(Error::MetaMethodRestricted(key.to_string())); } self.0.raw_set(key.name(), value) } /// Checks whether the metatable contains a non-nil value for `key`. pub fn contains<K: Into<MetaMethod>>(&self, key: K) -> Result<bool> { self.0.contains_key(key.into().validate()?.name()) } /// Consumes this metatable and returns an iterator over the pairs of the metatable. /// /// The pairs are wrapped in a [`Result`], since they are lazily converted to `V` type. /// /// [`Result`]: type.Result.html pub fn pairs<V: FromLua<'lua>>(self) -> UserDataMetatablePairs<'lua, V> { UserDataMetatablePairs(self.0.pairs()) } } /// An iterator over the pairs of a [`UserData`] metatable. /// /// It skips restricted metamethods, such as `__gc` or `__metatable`. /// /// This struct is created by the [`UserDataMetatable::pairs`] method. /// /// [`UserData`]: trait.UserData.html /// [`UserDataMetatable::pairs`]: struct.UserDataMetatable.html#method.pairs pub struct UserDataMetatablePairs<'lua, V>(TablePairs<'lua, StdString, V>); impl<'lua, V> Iterator for UserDataMetatablePairs<'lua, V> where V: FromLua<'lua>, { type Item = Result<(MetaMethod, V)>; fn next(&mut self) -> Option<Self::Item> { loop { match self.0.next()? { Ok((key, value)) => { // Skip restricted metamethods if let Ok(metamethod) = MetaMethod::from(key).validate() { break Some(Ok((metamethod, value))); } } Err(e) => break Some(Err(e)), } } } } #[cfg(feature = "serialize")] impl<'lua> Serialize for AnyUserData<'lua> { fn serialize<S>(&self, serializer: S) -> StdResult<S::Ok, S::Error> where S: Serializer, { let res = (|| unsafe { let lua = self.0.lua; let _sg = StackGuard::new(lua.state); check_stack(lua.state, 3)?; lua.push_userdata_ref(&self.0)?; let ud = &*get_userdata::<UserDataCell<()>>(lua.state, -1); (*ud.try_borrow().map_err(|_| Error::UserDataBorrowError)?.ser) .serialize(serializer) .map_err(|err| Error::SerializeError(err.to_string())) })(); res.map_err(ser::Error::custom) } }