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use crate::alloc::collections::BinaryHeap;
use core::{any::TypeId, fmt, mem::MaybeUninit, slice};
use crate::{
archetype::{TypeIdMap, TypeInfo},
Archetype, Component,
};
#[derive(Debug, Clone, Default)]
pub struct ColumnBatchType {
types: BinaryHeap<TypeInfo>,
}
impl ColumnBatchType {
pub fn new() -> Self {
Self::default()
}
pub fn add<T: Component>(&mut self) -> &mut Self {
self.types.push(TypeInfo::of::<T>());
self
}
pub fn into_batch(self, size: u32) -> ColumnBatchBuilder {
let mut types = self.types.into_sorted_vec();
types.dedup();
let fill = TypeIdMap::with_capacity_and_hasher(types.len(), Default::default());
let mut arch = Archetype::new(types);
arch.reserve(size);
ColumnBatchBuilder {
fill,
target_fill: size,
archetype: Some(arch),
}
}
}
pub struct ColumnBatchBuilder {
fill: TypeIdMap<u32>,
target_fill: u32,
pub(crate) archetype: Option<Archetype>,
}
unsafe impl Send for ColumnBatchBuilder {}
unsafe impl Sync for ColumnBatchBuilder {}
impl ColumnBatchBuilder {
pub fn new(ty: ColumnBatchType, size: u32) -> Self {
ty.into_batch(size)
}
pub fn writer<T: Component>(&mut self) -> Option<BatchWriter<'_, T>> {
let archetype = self.archetype.as_mut().unwrap();
let state = archetype.get_state::<T>()?;
let base = archetype.get_base::<T>(state);
Some(BatchWriter {
fill: self.fill.entry(TypeId::of::<T>()).or_insert(0),
storage: unsafe {
slice::from_raw_parts_mut(base.as_ptr().cast(), self.target_fill as usize)
.iter_mut()
},
})
}
pub fn build(mut self) -> Result<ColumnBatch, BatchIncomplete> {
let mut archetype = self.archetype.take().unwrap();
if archetype
.types()
.iter()
.any(|ty| self.fill.get(&ty.id()).copied().unwrap_or(0) != self.target_fill)
{
return Err(BatchIncomplete { _opaque: () });
}
unsafe {
archetype.set_len(self.target_fill);
}
Ok(ColumnBatch(archetype))
}
}
impl Drop for ColumnBatchBuilder {
fn drop(&mut self) {
if let Some(archetype) = self.archetype.take() {
for ty in archetype.types() {
let fill = self.fill.get(&ty.id()).copied().unwrap_or(0);
unsafe {
let base = archetype.get_dynamic(ty.id(), 0, 0).unwrap();
for i in 0..fill {
base.as_ptr().add(i as usize).drop_in_place()
}
}
}
}
}
}
pub struct ColumnBatch(pub(crate) Archetype);
pub struct BatchWriter<'a, T> {
fill: &'a mut u32,
storage: core::slice::IterMut<'a, MaybeUninit<T>>,
}
impl<T> BatchWriter<'_, T> {
pub fn push(&mut self, x: T) -> Result<(), T> {
match self.storage.next() {
None => Err(x),
Some(slot) => {
*slot = MaybeUninit::new(x);
*self.fill += 1;
Ok(())
}
}
}
pub fn fill(&self) -> u32 {
*self.fill
}
}
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct BatchIncomplete {
_opaque: (),
}
#[cfg(feature = "std")]
impl std::error::Error for BatchIncomplete {}
impl fmt::Display for BatchIncomplete {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("batch incomplete")
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn empty_batch() {
let mut types = ColumnBatchType::new();
types.add::<usize>();
let mut builder = types.into_batch(0);
let mut writer = builder.writer::<usize>().unwrap();
assert!(writer.push(42).is_err());
}
}