Cleanup Redox repo, update Rust, remove old target

src/sync/wait_condition.rs

@@ -0,0 +1,48 @@
+use alloc::arc::Arc;
+use collections::Vec;
+use spin::{Mutex, RwLock};
+
+use context::{self, Context};
+
+#[derive(Debug)]
+pub struct WaitCondition {
+    contexts: Mutex<Vec<Arc<RwLock<Context>>>>
+}
+
+impl WaitCondition {
+    pub fn new() -> WaitCondition {
+        WaitCondition {
+            contexts: Mutex::new(Vec::with_capacity(16))
+        }
+    }
+
+    pub fn notify(&self) -> usize {
+        let mut contexts = self.contexts.lock();
+        let len = contexts.len();
+        while let Some(context_lock) = contexts.pop() {
+            context_lock.write().unblock();
+        }
+        len
+    }
+
+    pub fn wait(&self) {
+        {
+            let context_lock = {
+                let contexts = context::contexts();
+                let context_lock = contexts.current().expect("WaitCondition::wait: no context");
+                context_lock.clone()
+            };
+
+            context_lock.write().block();
+
+            self.contexts.lock().push(context_lock);
+        }
+        unsafe { context::switch(); }
+    }
+}
+
+impl Drop for WaitCondition {
+    fn drop(&mut self){
+        self.notify();
+    }
+}