#![doc(hidden)]
use std::{any::TypeId, marker::PhantomData};
use super::{DefaultFilter, Fetch, IntoIndexableIter, IntoView, ReadOnly, ReadOnlyFetch, View};
use crate::internals::{
iter::indexed::{IndexedIter, TrustedRandomAccess},
permissions::Permissions,
query::{
filter::{passthrough::Passthrough, try_component::TryComponentFilter, EntityFilterTuple},
QueryResult,
},
storage::{
archetype::{Archetype, ArchetypeIndex},
component::{Component, ComponentTypeId},
ComponentSlice, ComponentStorage, Components,
},
subworld::ComponentAccess,
};
#[derive(Debug, Copy, Clone)]
pub struct TryRead<T>(PhantomData<*const T>);
impl<T> Default for TryRead<T> {
fn default() -> Self {
Self(PhantomData)
}
}
unsafe impl<T> Send for TryRead<T> {}
unsafe impl<T: Sync> Sync for TryRead<T> {}
unsafe impl<T> ReadOnly for TryRead<T> {}
impl<T: Component> DefaultFilter for TryRead<T> {
type Filter = EntityFilterTuple<TryComponentFilter<T>, Passthrough>;
}
impl<T: Component> IntoView for TryRead<T> {
type View = Self;
}
impl<'data, T: Component> View<'data> for TryRead<T> {
type Element = <Self::Fetch as IntoIndexableIter>::Item;
type Fetch = Slice<'data, T>;
type Iter = TryReadIter<'data, T>;
type Read = [ComponentTypeId; 1];
type Write = [ComponentTypeId; 0];
#[inline]
fn validate() {}
#[inline]
fn validate_access(access: &ComponentAccess) -> bool {
access.allows_read(ComponentTypeId::of::<T>())
}
#[inline]
fn reads_types() -> Self::Read {
[ComponentTypeId::of::<T>()]
}
#[inline]
fn writes_types() -> Self::Write {
[]
}
#[inline]
fn reads<D: Component>() -> bool {
TypeId::of::<T>() == TypeId::of::<D>()
}
#[inline]
fn writes<D: Component>() -> bool {
false
}
#[inline]
fn requires_permissions() -> Permissions<ComponentTypeId> {
let mut permissions = Permissions::default();
permissions.push_read(ComponentTypeId::of::<T>());
permissions
}
unsafe fn fetch(
components: &'data Components,
archetypes: &'data [Archetype],
query: QueryResult<'data>,
) -> Self::Iter {
let components = components.get_downcast::<T>();
let archetype_indexes = query.index().iter();
TryReadIter {
components,
archetypes,
archetype_indexes,
}
}
}
#[doc(hidden)]
pub struct TryReadIter<'a, T: Component> {
components: Option<&'a T::Storage>,
archetype_indexes: std::slice::Iter<'a, ArchetypeIndex>,
archetypes: &'a [Archetype],
}
impl<'a, T: Component> Iterator for TryReadIter<'a, T> {
type Item = Option<Slice<'a, T>>;
#[inline]
fn next(&mut self) -> Option<Self::Item> {
self.archetype_indexes.next().map(|i| {
let slice = self
.components
.and_then(|components| components.get(*i))
.map_or_else(
|| Slice::Empty(self.archetypes[*i].entities().len()),
|c| c.into(),
);
Some(slice)
})
}
}
#[doc(hidden)]
pub enum Slice<'a, T: Component> {
Occupied {
version: &'a u64,
components: &'a [T],
},
Empty(usize),
}
impl<'a, T: Component> From<ComponentSlice<'a, T>> for Slice<'a, T> {
fn from(slice: ComponentSlice<'a, T>) -> Self {
Slice::Occupied {
components: slice.components,
version: slice.version,
}
}
}
impl<'a, T: Component> IntoIndexableIter for Slice<'a, T> {
type Item = Option<&'a T>;
type IntoIter = IndexedIter<Data<'a, T>>;
fn into_indexable_iter(self) -> Self::IntoIter {
let data = match self {
Self::Occupied { components, .. } => Data::Occupied(components),
Self::Empty(count) => Data::Empty(count),
};
IndexedIter::new(data)
}
}
impl<'a, T: Component> IntoIterator for Slice<'a, T> {
type Item = <Self as IntoIndexableIter>::Item;
type IntoIter = <Self as IntoIndexableIter>::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.into_indexable_iter()
}
}
unsafe impl<'a, T: Component> ReadOnlyFetch for Slice<'a, T> {
fn get_components(&self) -> Self::Data {
match self {
Self::Occupied { components, .. } => Some(components),
Self::Empty(_) => None,
}
}
}
impl<'a, T: Component> Fetch for Slice<'a, T> {
type Data = Option<&'a [T]>;
#[inline]
fn into_components(self) -> Self::Data {
match self {
Self::Occupied { components, .. } => Some(components),
Self::Empty(_) => None,
}
}
#[inline]
fn find<C: 'static>(&self) -> Option<&[C]> {
if TypeId::of::<C>() == TypeId::of::<T>() {
match self {
Self::Occupied { components, .. } => {
Some(unsafe {
std::slice::from_raw_parts(
components.as_ptr() as *const C,
components.len(),
)
})
}
Self::Empty(_) => None,
}
} else {
None
}
}
#[inline]
fn find_mut<C: 'static>(&mut self) -> Option<&mut [C]> {
None
}
#[inline]
fn version<C: Component>(&self) -> Option<u64> {
if TypeId::of::<C>() == TypeId::of::<T>() {
match self {
Self::Occupied { version, .. } => Some(**version),
Self::Empty(_) => None,
}
} else {
None
}
}
#[inline]
fn accepted(&mut self) {}
}
#[doc(hidden)]
pub enum Data<'a, T: Component> {
Occupied(&'a [T]),
Empty(usize),
}
unsafe impl<'a, T: Component> TrustedRandomAccess for Data<'a, T> {
type Item = Option<&'a T>;
#[inline]
fn len(&self) -> usize {
match self {
Self::Occupied(slice) => slice.len(),
Self::Empty(len) => *len,
}
}
#[inline]
unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
match self {
Self::Occupied(slice) => Some(slice.get_unchecked(i)),
Self::Empty(_) => None,
}
}
#[inline]
fn split_at(self, index: usize) -> (Self, Self) {
match self {
Self::Occupied(slice) => {
let (left, right) = slice.split_at(index);
(Self::Occupied(left), Self::Occupied(right))
}
Self::Empty(count) => {
debug_assert!(index < count);
(Self::Empty(index), Self::Empty(count - index))
}
}
}
}