4lDO2
93 lines
2.3 KiB
Rust
93 lines
2.3 KiB
Rust
use alloc::{sync::Arc, vec::Vec};
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use spin::{Mutex, MutexGuard};
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use spinning_top::RwSpinlock;
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use crate::context::{self, Context};
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#[derive(Debug)]
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pub struct WaitCondition {
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contexts: Mutex<Vec<Arc<RwSpinlock<Context>>>>,
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}
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impl WaitCondition {
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pub const fn new() -> WaitCondition {
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WaitCondition {
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contexts: Mutex::new(Vec::new()),
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}
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}
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// Notify all waiters
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pub fn notify(&self) -> usize {
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let mut contexts = self.contexts.lock();
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let len = contexts.len();
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while let Some(context_lock) = contexts.pop() {
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context_lock.write().unblock();
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}
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len
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}
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// Notify as though a signal woke the waiters
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pub unsafe fn notify_signal(&self) -> usize {
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let contexts = self.contexts.lock();
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let len = contexts.len();
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for context_lock in contexts.iter() {
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context_lock.write().unblock();
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}
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len
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}
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// Wait until notified. Unlocks guard when blocking is ready. Returns false if resumed by a signal or the notify_signal function
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pub fn wait<T>(&self, guard: MutexGuard<T>, reason: &'static str) -> bool {
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let id;
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{
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let context_lock = {
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let contexts = context::contexts();
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let context_lock = contexts.current().expect("WaitCondition::wait: no context");
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Arc::clone(context_lock)
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};
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{
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let mut context = context_lock.write();
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id = context.id;
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context.block(reason);
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}
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self.contexts.lock().push(context_lock);
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drop(guard);
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}
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context::switch();
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let mut waited = true;
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{
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let mut contexts = self.contexts.lock();
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let mut i = 0;
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while i < contexts.len() {
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let remove = {
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let context = contexts[i].read();
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context.id == id
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};
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if remove {
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contexts.remove(i);
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waited = false;
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break;
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} else {
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i += 1;
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}
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}
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}
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waited
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}
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}
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impl Drop for WaitCondition {
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fn drop(&mut self) {
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unsafe { self.notify_signal() };
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}
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}
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