1 files changed, 40 insertions, 0 deletions
diff --git a/jsonrpc/src/server/response_queue.rs b/jsonrpc/src/server/response_queue.rs
new file mode 100644
index 0000000..0d70503
--- /dev/null
+++ b/jsonrpc/src/server/response_queue.rs
@@ -0,0 +1,40 @@
+use std::{collections::VecDeque, sync::Arc};
+
+use karyon_core::{async_runtime::lock::Mutex, async_util::CondVar};
+
+/// A queue for handling responses
+pub(super) struct ResponseQueue<T> {
+    queue: Mutex<VecDeque<T>>,
+    condvar: CondVar,
+}
+
+impl<T: std::fmt::Debug> ResponseQueue<T> {
+    pub(super) fn new() -> Arc<Self> {
+        Arc::new(Self {
+            queue: Mutex::new(VecDeque::new()),
+            condvar: CondVar::new(),
+        })
+    }
+
+    /// Wait while the queue is empty, remove and return the item from the queue,
+    /// panicking if empty (shouldn't happen)
+    pub(super) async fn recv(&self) -> T {
+        let mut queue = self.queue.lock().await;
+
+        while queue.is_empty() {
+            queue = self.condvar.wait(queue).await;
+        }
+
+        match queue.pop_front() {
+            Some(v) => v,
+            None => unreachable!(),
+        }
+    }
+
+    /// Push an item into the queue, notify all waiting tasks that the
+    /// condvar has changed
+    pub(super) async fn push(&self, res: T) {
+        self.queue.lock().await.push_back(res);
+        self.condvar.signal();
+    }
+}