Create timesync JNI for testing client (#1433)

2026-06-20 00:51:41 +00:00 · 2024-10-31 08:27:19 -07:00
parent 937bafa8e2
commit 37aaa49b32
69 changed files with 2252 additions and 368 deletions
--- a/photon-targeting/src/main/java/org/photonvision/jni/TimeSyncClient.java
+++ b/photon-targeting/src/main/java/org/photonvision/jni/TimeSyncClient.java
@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) Photon Vision.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package org.photonvision.jni;
+
+import edu.wpi.first.networktables.NetworkTablesJNI;
+
+/**
+ * Send ping-pongs to estimate server time, relative to nt::Now. The underlying implementation does
+ * technically allow us to provide a different source, but all photon code assumes nt::Now is used
+ */
+public class TimeSyncClient {
+    public static class PingMetadata {
+        // offset, us
+        public long offset;
+        // outgoing count
+        public long pingsSent;
+        // incoming count
+        public long pongsReceived;
+        // when we last heard back from the server
+        public long lastPongTime;
+        // RTT2, time from ping send to pong recieve at the client
+        public long rtt2;
+
+        public PingMetadata(
+                long offset, long pingsSent, long pongsReceived, long lastPongTime, long rtt2) {
+            this.offset = offset;
+            this.pingsSent = pingsSent;
+            this.pongsReceived = pongsReceived;
+            this.lastPongTime = lastPongTime;
+            this.rtt2 = rtt2;
+        }
+
+        @Override
+        public String toString() {
+            return "PingMetadata [offset="
+                    + offset
+                    + ", pingsSent="
+                    + pingsSent
+                    + ", pongsReceived="
+                    + pongsReceived
+                    + ", lastPongTime="
+                    + lastPongTime
+                    + ", rtt2="
+                    + rtt2
+                    + "]";
+        }
+
+        /**
+         * How long, in us, since we last heard back from the server
+         *
+         * @return Time between last pong RX and now, or Long.MAX_VALUE if we have heard zero pongs
+         */
+        public long timeSinceLastPong() {
+            // If no pongs, it's been forever
+            if (pongsReceived < 1) {
+                return Long.MAX_VALUE;
+            }
+
+            return NetworkTablesJNI.now() - lastPongTime;
+        }
+    }
+
+    private final Object mutex = new Object();
+
+    private long handle;
+    private String server;
+    private int port;
+    private double interval;
+
+    public TimeSyncClient(String server, int port, double interval) {
+        this.server = server;
+        this.port = port;
+        this.interval = interval;
+
+        synchronized (mutex) {
+            this.handle = TimeSyncClient.create(server, port, interval);
+            TimeSyncClient.start(handle);
+        }
+    }
+
+    public void setServer(String newServer) {
+        if (!server.equals(newServer)) {
+            synchronized (mutex) {
+                stop();
+                this.handle = TimeSyncClient.create(newServer, port, interval);
+                TimeSyncClient.start(handle);
+                this.server = newServer;
+            }
+        }
+    }
+
+    public void stop() {
+        synchronized (mutex) {
+            if (handle > 0) {
+                TimeSyncClient.stop(handle);
+                handle = 0;
+            }
+        }
+    }
+
+    /**
+     * This offset, when added to the current value of nt::now(), yields the timestamp in the timebase
+     * of the TSP Server
+     *
+     * @return
+     */
+    public long getOffset() {
+        synchronized (mutex) {
+            return TimeSyncClient.getOffset(handle);
+        }
+    }
+
+    /**
+     * Best estimate of the current timestamp at the TSP server
+     *
+     * @return The current time estimate, in microseconds, at the TSP server
+     */
+    public long currentServerTimestamp() {
+        return NetworkTablesJNI.now() + getOffset();
+    }
+
+    public PingMetadata getPingMetadata() {
+        synchronized (mutex) {
+            return TimeSyncClient.getLatestMetadata(handle);
+        }
+    }
+
+    public String getServer() {
+        return server;
+    }
+
+    private static native long create(String serverIP, int serverPort, double pingIntervalSeconds);
+
+    private static native void start(long handle);
+
+    private static native void stop(long handle);
+
+    private static native long getOffset(long handle);
+
+    private static native PingMetadata getLatestMetadata(long handle);
+}