From 3fbf67e217fb489fe7318a9e43d8ae86646eb4cc Mon Sep 17 00:00:00 2001
From: Jean-Michel Trivi <jmtrivi@google.com>
Date: Tue, 9 Apr 2013 11:10:18 -0700
Subject: [PATCH] Handle seek requests in AudioService

AudioService handles seek requests to RemoteControlClients.
Discard old or unprocessed seek requests when handling a new one.
Update javadoc for OnPlaybackPositionUpdateListener interface.

bug 8120740

Change-Id: Id17c2852b24d4b8af85e472a177484b98cfeba05
---
 media/java/android/media/AudioService.java        | 14 +++++++++++++-
 media/java/android/media/RemoteControlClient.java |  5 ++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/media/java/android/media/AudioService.java b/media/java/android/media/AudioService.java
index fd71d79b13f11..a000cdd0f156b 100644
--- a/media/java/android/media/AudioService.java
+++ b/media/java/android/media/AudioService.java
@@ -3535,6 +3535,9 @@ public class AudioService extends IAudioService.Stub implements OnFinished {
                     onNewPlaybackStateForRcc(msg.arg1 /* rccId */, msg.arg2 /* state */,
                             (RccPlaybackState)msg.obj /* newState */);
                     break;
+                case MSG_RCC_SEEK_REQUEST:
+                    onSetRemoteControlClientPlaybackPosition(msg.arg1 /* generationId */,
+                            ((Long)msg.obj).longValue() /* timeMs */);
 
                 case MSG_SET_RSX_CONNECTION_STATE:
                     onSetRsxConnectionState(msg.arg1/*available*/, msg.arg2/*address*/);
@@ -5820,7 +5823,16 @@ public class AudioService extends IAudioService.Stub implements OnFinished {
     }
 
     public void setRemoteControlClientPlaybackPosition(int generationId, long timeMs) {
-        sendMsg(mAudioHandler, MSG_RCC_SEEK_REQUEST, SENDMSG_QUEUE, generationId /* arg1 */,
+        // ignore position change requests if invalid generation ID
+        synchronized(mRCStack) {
+            synchronized(mCurrentRcLock) {
+                if (mCurrentRcClientGen != generationId) {
+                    return;
+                }
+            }
+        }
+        // discard any unprocessed seek request in the message queue, and replace with latest
+        sendMsg(mAudioHandler, MSG_RCC_SEEK_REQUEST, SENDMSG_REPLACE, generationId /* arg1 */,
                 0 /* arg2 ignored*/, new Long(timeMs) /* obj */, 0 /* delay */);
     }
 
diff --git a/media/java/android/media/RemoteControlClient.java b/media/java/android/media/RemoteControlClient.java
index e076ef0044d79..93bcf03bb4635 100644
--- a/media/java/android/media/RemoteControlClient.java
+++ b/media/java/android/media/RemoteControlClient.java
@@ -683,9 +683,12 @@ public class RemoteControlClient
         /**
          * Called on the implementer to notify it that the playback head should be set at the given
          * position. If the position can be changed from its current value, the implementor of
-         * the interface should also update the playback position using
+         * the interface must also update the playback position using
          * {@link RemoteControlClient#setPlaybackState(int, long, int)} to reflect the actual new
          * position being used, regardless of whether it differs from the requested position.
+         * Failure to do so would cause the system to not know the new actual playback position,
+         * and user interface components would fail to show the user where playback resumed after
+         * the position was updated.
          * @param newPositionMs the new requested position in the current media, expressed in ms.
          */
         void onPlaybackPositionUpdate(long newPositionMs);