use std::ops::Range;
use super::{MmapFile, read_bytes};
use crate::common::ext::aligned_vec::ACow;
use crate::common::generic_consts::{AccessPattern, Random, Sequential};
use crate::common::universal_io::{
BorrowedReadPipeline, OwnedReadPipeline, Result, UniversalIoError, UniversalRead, UserData,
};
pub struct BorrowedMmapReadPipeline<'file, U> {
result: Option<(U, &'file [u8])>,
}
impl<'file, U> BorrowedReadPipeline<'file, U> for BorrowedMmapReadPipeline<'file, U>
where
U: UserData,
{
type File = MmapFile;
fn new() -> Result<Self> {
Ok(Self { result: None })
}
fn can_schedule(&mut self) -> bool {
self.result.is_none()
}
fn schedule<P: AccessPattern>(
&mut self,
user_data: U,
file: &'file MmapFile,
range: Range<u64>,
_align: usize,
) -> Result<()> {
if self.result.is_some() {
return Err(UniversalIoError::QueueIsFull);
}
self.result = Some((user_data, read_bytes(file.as_bytes::<P>(), range)?));
Ok(())
}
fn wait(&mut self) -> Result<Option<(U, ACow<'file>)>> {
let result = self.result.take();
Ok(result.map(|(user_data, bytes)| (user_data, ACow::Borrowed(bytes))))
}
}
#[derive(Debug)]
pub struct OwnedMmapReadPipeline<U> {
file: MmapFile,
pending: Option<(U, Range<u64>, bool)>,
}
impl<U> OwnedReadPipeline<U> for OwnedMmapReadPipeline<U>
where
U: UserData,
{
type File = MmapFile;
fn new(file: MmapFile) -> Result<Self> {
Ok(Self {
file,
pending: None,
})
}
fn can_schedule(&mut self) -> bool {
self.pending.is_none()
}
fn schedule<P: AccessPattern>(
&mut self,
user_data: U,
range: Range<u64>,
_align: usize,
) -> Result<()> {
if self.pending.is_some() {
return Err(UniversalIoError::QueueIsFull);
}
self.pending = Some((user_data, range, P::IS_SEQUENTIAL));
Ok(())
}
fn schedule_whole(&mut self, user_data: U) -> Result<()> {
let length = self.file.len::<u8>()?;
self.schedule::<Sequential>(user_data, 0..length, 1)
}
fn wait(&mut self) -> Result<Option<(U, ACow<'_>)>> {
let Some((user_data, range, is_sequential)) = self.pending.take() else {
return Ok(None);
};
let bytes = if is_sequential {
self.file.as_bytes::<Sequential>()
} else {
self.file.as_bytes::<Random>()
};
let slice = read_bytes(bytes, range)?;
Ok(Some((user_data, ACow::Borrowed(slice))))
}
}