[ISSUE #1125]🔊Implementing functionality similar to Java's LinkedBloc…

…kingQueue in Rust using Tokio🚀 (#1126)

rocketmq/src/blocking_queue.rs

@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use std::collections::VecDeque;
+
+use tokio::sync::Mutex;
+use tokio::sync::Notify;
+use tokio::time;
+
+pub struct BlockingQueue<T> {
+    queue: Mutex<VecDeque<T>>,
+    capacity: usize,
+    notify: Notify,
+}
+
+impl<T> BlockingQueue<T> {
+    pub fn new(capacity: usize) -> Self {
+        BlockingQueue {
+            queue: Mutex::new(VecDeque::with_capacity(capacity)),
+            capacity,
+            notify: Notify::new(),
+        }
+    }
+
+    pub async fn put(&self, item: T) {
+        loop {
+            {
+                let mut queue = self.queue.lock().await;
+                if queue.len() < self.capacity {
+                    queue.push_back(item);
+                    self.notify.notify_one(); // Notify only after successful push
+                    return;
+                }
+            }
+            self.notify.notified().await;
+        }
+    }
+
+    pub async fn offer(&self, item: T, timeout: std::time::Duration) -> bool {
+        time::timeout(timeout, self.put(item)).await.is_ok()
+    }
+
+    pub async fn take(&self) -> T {
+        loop {
+            {
+                let mut queue = self.queue.lock().await;
+                if let Some(item) = queue.pop_front() {
+                    self.notify.notify_one(); // Notify only after successful pop
+                    return item;
+                }
+            }
+            self.notify.notified().await;
+        }
+    }
+
+    pub async fn poll(&self, timeout: std::time::Duration) -> Option<T> {
+        time::timeout(timeout, self.take()).await.ok()
+    }
+}

rocketmq/src/lib.rs

@@ -17,13 +17,15 @@
 #![feature(sync_unsafe_cell)]
 
 mod arc_mut;
+mod blocking_queue;
 pub mod count_down_latch;
 pub mod rocketmq_tokio_lock;
 mod shutdown;
 
 pub use arc_mut::ArcMut;
 pub use arc_mut::SyncUnsafeCellWrapper;
 pub use arc_mut::WeakArcMut;
+pub use blocking_queue::BlockingQueue as RocketMQBlockingQueue;
 pub use count_down_latch::CountDownLatch;
 /// Re-export rocketmq main.
 pub use rocketmq::main;