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
// Copyright 2019 Google LLC // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // https://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. use std::any::{type_name, TypeId}; use std::ptr::NonNull; use std::{fmt, mem}; use crate::archetype::TypeInfo; use crate::Component; /// A dynamically typed collection of components pub trait DynamicBundle { #[doc(hidden)] fn with_ids<T>(&self, f: impl FnOnce(&[TypeId]) -> T) -> T; #[doc(hidden)] fn type_info(&self) -> Vec<TypeInfo>; /// Allow a callback to move all components out of the bundle /// /// Must invoke `f` only with a valid pointer, its type, and the pointee's size. A `false` /// return value indicates that the value was not moved and should be dropped. #[doc(hidden)] unsafe fn put(self, f: impl FnMut(*mut u8, TypeId, usize) -> bool); } /// A statically typed collection of components pub trait Bundle: DynamicBundle { #[doc(hidden)] fn with_static_ids<T>(f: impl FnOnce(&[TypeId]) -> T) -> T; /// Construct `Self` by moving components out of pointers fetched by `f` #[doc(hidden)] unsafe fn get( f: impl FnMut(TypeId, usize) -> Option<NonNull<u8>>, ) -> Result<Self, MissingComponent> where Self: Sized; } /// Error indicating that an entity did not have a required component #[derive(Debug, Clone, Eq, PartialEq, Hash)] pub struct MissingComponent(&'static str); impl MissingComponent { /// Construct an error representing a missing `T` pub fn new<T: Component>() -> Self { Self(type_name::<T>()) } } impl fmt::Display for MissingComponent { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "missing {} component", self.0) } } impl std::error::Error for MissingComponent {} macro_rules! tuple_impl { ($($name: ident),*) => { impl<$($name: Component),*> DynamicBundle for ($($name,)*) { fn with_ids<T>(&self, f: impl FnOnce(&[TypeId]) -> T) -> T { Self::with_static_ids(f) } fn type_info(&self) -> Vec<TypeInfo> { let mut xs = vec![$(TypeInfo::of::<$name>()),*]; xs.sort_unstable(); xs } #[allow(unused_variables, unused_mut)] unsafe fn put(self, mut f: impl FnMut(*mut u8, TypeId, usize) -> bool) { #[allow(non_snake_case)] let ($(mut $name,)*) = self; $( if f( (&mut $name as *mut $name).cast::<u8>(), TypeId::of::<$name>(), mem::size_of::<$name>() ) { mem::forget($name) } )* } } impl<$($name: Component),*> Bundle for ($($name,)*) { fn with_static_ids<T>(f: impl FnOnce(&[TypeId]) -> T) -> T { const N: usize = count!($($name),*); let mut xs: [(usize, TypeId); N] = [$((std::mem::align_of::<$name>(), TypeId::of::<$name>())),*]; xs.sort_unstable_by(|x, y| x.0.cmp(&y.0).reverse().then(x.1.cmp(&y.1))); let mut ids = [TypeId::of::<()>(); N]; for (slot, &(_, id)) in ids.iter_mut().zip(xs.iter()) { *slot = id; } f(&ids) } #[allow(unused_variables, unused_mut)] unsafe fn get(mut f: impl FnMut(TypeId, usize) -> Option<NonNull<u8>>) -> Result<Self, MissingComponent> { Ok(($( f(TypeId::of::<$name>(), mem::size_of::<$name>()) .ok_or_else(MissingComponent::new::<$name>)? .as_ptr() .cast::<$name>() .read(), )*)) } } } } macro_rules! count { () => { 0 }; ($x: ident $(, $rest: ident)*) => { 1 + count!($($rest),*) }; } tuple_impl!(); tuple_impl!(A); tuple_impl!(A, B); tuple_impl!(A, B, C); tuple_impl!(A, B, C, D); tuple_impl!(A, B, C, D, E); tuple_impl!(A, B, C, D, E, F); tuple_impl!(A, B, C, D, E, F, G); tuple_impl!(A, B, C, D, E, F, G, H); tuple_impl!(A, B, C, D, E, F, G, H, I); tuple_impl!(A, B, C, D, E, F, G, H, I, J); tuple_impl!(A, B, C, D, E, F, G, H, I, J, K); tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L); tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M); tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N); tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA, AB); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA, AB, AC); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA, AB, AC, AD); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA, AB, AC, AD, AE); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA, AB, AC, AD, AE, AF); // tuple_impl!(A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA, AB, AC, AD, AE, AF, AG);