Wildan M
89 lines
2.6 KiB
Rust
89 lines
2.6 KiB
Rust
use alloc::collections::VecDeque;
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use spin::Mutex;
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use syscall::{EAGAIN, EINTR};
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use crate::{
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sync::{CleanLockToken, LockToken, WaitCondition, L1},
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syscall::{
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error::{Error, Result, EINVAL},
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usercopy::UserSliceWo,
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},
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};
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#[derive(Debug)]
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pub struct WaitQueue<T> {
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pub inner: Mutex<VecDeque<T>>,
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pub condition: WaitCondition,
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}
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impl<T> WaitQueue<T> {
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pub const fn new() -> WaitQueue<T> {
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WaitQueue {
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inner: Mutex::new(VecDeque::new()),
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condition: WaitCondition::new(),
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}
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}
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pub fn is_currently_empty(&self) -> bool {
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self.inner.lock().is_empty()
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}
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pub fn receive_into_user(
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&self,
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buf: UserSliceWo,
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block: bool,
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reason: &'static str,
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token: &mut CleanLockToken,
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) -> Result<usize> {
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loop {
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let mut inner = self.inner.lock();
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if inner.is_empty() {
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if block {
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if !self.condition.wait(inner, reason, token) {
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return Err(Error::new(EINTR));
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}
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continue;
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} else if buf.is_empty() {
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return Ok(0);
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} else if buf.len() < core::mem::size_of::<T>() {
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return Err(Error::new(EINVAL));
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} else {
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// TODO: EWOULDBLOCK?
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return Err(Error::new(EAGAIN));
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}
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}
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let (s1, s2) = inner.as_slices();
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let s1_bytes = unsafe {
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core::slice::from_raw_parts(s1.as_ptr().cast::<u8>(), core::mem::size_of_val(s1))
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};
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let s2_bytes = unsafe {
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core::slice::from_raw_parts(s2.as_ptr().cast::<u8>(), core::mem::size_of_val(s2))
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};
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let mut bytes_copied = buf.copy_common_bytes_from_slice(s1_bytes)?;
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if let Some(buf_for_s2) = buf.advance(s1_bytes.len()) {
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bytes_copied += buf_for_s2.copy_common_bytes_from_slice(s2_bytes)?;
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}
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let _ = inner.drain(..bytes_copied / core::mem::size_of::<T>());
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return Ok(bytes_copied);
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}
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}
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pub fn send(&self, value: T, token: &mut CleanLockToken) -> usize {
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self.send_locked(value, token.token().downgrade())
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}
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pub fn send_locked(&self, value: T, token: LockToken<'_, L1>) -> usize {
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let len = {
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let mut inner = self.inner.lock();
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inner.push_back(value);
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inner.len()
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};
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self.condition.notify_locked(token);
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len
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}
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}
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