From 43549dee0a8214c1bb02c874dcfd7ba37a8ef310 Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Fri, 22 Nov 2024 12:02:08 -0500
Subject: ReliableUnicastSender

---
 src/main/java/derms/net/runicast/ReceiveAcks.java | 59 +++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 src/main/java/derms/net/runicast/ReceiveAcks.java

(limited to 'src/main/java/derms/net/runicast/ReceiveAcks.java')

diff --git a/src/main/java/derms/net/runicast/ReceiveAcks.java b/src/main/java/derms/net/runicast/ReceiveAcks.java
new file mode 100644
index 0000000..0f585ff
--- /dev/null
+++ b/src/main/java/derms/net/runicast/ReceiveAcks.java
@@ -0,0 +1,59 @@
+package derms.net.runicast;
+
+import derms.net.ConcurrentDatagramSocket;
+import derms.net.MessagePayload;
+import derms.net.Packet;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.SocketTimeoutException;
+import java.util.Queue;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.logging.Logger;
+
+/** Receive acknowledgements. Remove messages from the sent queue once they are acknowledged. */
+class ReceiveAcks<T extends MessagePayload> implements Runnable {
+    private static final int bufSize = 8192;
+
+    private final AtomicLong unacked;
+    private final Queue<Message<T>> sent;
+    private final ConcurrentDatagramSocket sock;
+    private final Logger log;
+
+    ReceiveAcks(AtomicLong unacked, Queue<Message<T>> sent, ConcurrentDatagramSocket sock) {
+        this.unacked = unacked;
+        this.sent = sent;
+        this.sock = sock;
+        this.log = Logger.getLogger(getClass().getName());
+    }
+
+    @Override
+    public void run() {
+        DatagramPacket pkt = new DatagramPacket(new byte[bufSize], bufSize);
+        for (;;) {
+            try {
+                sock.receive(pkt);
+                Ack ack = Packet.decode(pkt, Ack.class);
+                recvAck(ack.seq);
+            } catch (SocketTimeoutException e) {
+                if (Thread.interrupted()) {
+                    log.info("Interrupted.");
+                    return;
+                }
+            } catch (IOException | ClassNotFoundException | ClassCastException e) {
+                log.warning(e.getMessage());
+            }
+        }
+    }
+
+    private void recvAck(long ack) {
+        unacked.updateAndGet((unacked) -> {
+            if (ack >= unacked)
+                return ack+1;
+            return unacked;
+        });
+
+        while (!sent.isEmpty() && sent.peek().seq <= ack)
+            sent.remove();
+    }
+}
-- 
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