From c60baabb1c0b6b2f700ec605cb309d5704b30b66 Mon Sep 17 00:00:00 2001
From: rohks <rohks@google.com>
Date: Mon, 15 Jul 2024 12:33:25 -0700
Subject: [PATCH] Allow changing SNTP client timeout

Added a method to set the timeout for the SNTP request.

Also changed the default timeout to 5s instead of 10s as it seemed quite high.

Issue: androidx/media#1540
PiperOrigin-RevId: 652566008
---
 RELEASENOTES.md                               |  2 ++
 .../media3/exoplayer/util/SntpClient.java     | 34 +++++++++++++++++--
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 855d04aaa2..625741f3b2 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -24,6 +24,8 @@
     *   `MediaCodecVideoRenderer` avoids decoding samples that are neither
         rendered nor used as reference by other samples.
     *   Add `BasePreloadManager.Listener` to propagate preload events to apps.
+    *   Allow changing SNTP client timeout
+        ([#1540](https://github.com/androidx/media/issues/1540)).
 *   Transformer:
     *   Add `SurfaceAssetLoader`, which supports queueing video data to
         Transformer via a `Surface`.
diff --git a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/util/SntpClient.java b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/util/SntpClient.java
index 2aa5112ec2..629c919134 100644
--- a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/util/SntpClient.java
+++ b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/util/SntpClient.java
@@ -43,6 +43,9 @@ public final class SntpClient {
   /** The default NTP host address used to retrieve {@link #getElapsedRealtimeOffsetMs()}. */
   public static final String DEFAULT_NTP_HOST = "time.android.com";
 
+  /** The default maximum time, in milliseconds, to wait for the SNTP request to complete. */
+  public static final int DEFAULT_TIMEOUT_MS = 5_000;
+
   /** Callback for calls to {@link #initialize(Loader, InitializationCallback)}. */
   public interface InitializationCallback {
 
@@ -57,8 +60,6 @@ public final class SntpClient {
     void onInitializationFailed(IOException error);
   }
 
-  private static final int TIMEOUT_MS = 10_000;
-
   private static final int ORIGINATE_TIME_OFFSET = 24;
   private static final int RECEIVE_TIME_OFFSET = 32;
   private static final int TRANSMIT_TIME_OFFSET = 40;
@@ -88,6 +89,9 @@ public final class SntpClient {
   @GuardedBy("valueLock")
   private static String ntpHost = DEFAULT_NTP_HOST;
 
+  @GuardedBy("valueLock")
+  private static int timeoutMs = DEFAULT_TIMEOUT_MS;
+
   private SntpClient() {}
 
   /** Returns the NTP host address used to retrieve {@link #getElapsedRealtimeOffsetMs()}. */
@@ -116,6 +120,30 @@ public final class SntpClient {
     }
   }
 
+  /** Returns the maximum time to wait for the SNTP request to complete, in milliseconds. */
+  public static int getTimeoutMs() {
+    synchronized (valueLock) {
+      return timeoutMs;
+    }
+  }
+
+  /**
+   * Sets the maximum time to wait for the SNTP request to complete, in milliseconds.
+   *
+   * <p>The default is {@link #DEFAULT_TIMEOUT_MS}.
+   *
+   * <p>If the new timeout is different from the previous one, the NTP client will be {@link
+   * #isInitialized()} uninitialized} again.
+   */
+  public static void setTimeoutMs(int timeoutMs) {
+    synchronized (valueLock) {
+      if (SntpClient.timeoutMs != timeoutMs) {
+        SntpClient.timeoutMs = timeoutMs;
+        isInitialized = false;
+      }
+    }
+  }
+
   /**
    * Returns whether the device time offset has already been loaded.
    *
@@ -165,7 +193,7 @@ public final class SntpClient {
   private static long loadNtpTimeOffsetMs() throws IOException {
     InetAddress address = InetAddress.getByName(getNtpHost());
     try (DatagramSocket socket = new DatagramSocket()) {
-      socket.setSoTimeout(TIMEOUT_MS);
+      socket.setSoTimeout(getTimeoutMs());
       byte[] buffer = new byte[NTP_PACKET_SIZE];
       DatagramPacket request = new DatagramPacket(buffer, buffer.length, address, NTP_PORT);