Introduce MessageSession, for keeping track of messages to send to clients

server/src/message_session.rs

@@ -0,0 +1,57 @@
+use std::collections::HashMap;
+use std::sync::{mpsc, Arc, RwLock, Mutex};
+
+use id::{Id, get_id};
+
+#[derive(Debug, Clone, Serialize)]
+pub enum Message {
+    Something,
+}
+
+#[derive(Clone)]
+pub struct MessageSession {
+   pub messages: Arc<RwLock<Vec<Message>>>,
+   pub message_listeners: Arc<Mutex<HashMap<Id, mpsc::Sender<()>>>>,
+}
+
+impl MessageSession {
+    pub fn new() -> MessageSession {
+        MessageSession {
+            messages: Arc::new(RwLock::new(Vec::new())),
+            message_listeners: Arc::new(Mutex::new(HashMap::new())),
+        }
+    }
+
+    pub fn push_messages(&self, new_messages: &[Message]) {
+        {
+            let mut messages = self.messages.write().unwrap();
+            messages.extend_from_slice(new_messages);
+        }
+
+        {
+            let message_listeners = self.message_listeners.lock().unwrap();
+
+            for listener in message_listeners.values() {
+                listener.send(()).unwrap();
+            }
+        }
+    }
+
+    pub fn subscribe(&self, sender: mpsc::Sender<()>) -> Id {
+        let id = get_id();
+
+        {
+            let mut message_listeners = self.message_listeners.lock().unwrap();
+            message_listeners.insert(id, sender);
+        }
+
+        id
+    }
+
+    pub fn unsubscribe(&self, id: Id) {
+        {
+            let mut message_listeners = self.message_listeners.lock().unwrap();
+            message_listeners.remove(&id);
+        }
+    }
+}