Merge "Simplify synchronized code and add comments" am: 9791b54b88 am: b57f32e68a am: 9760c42784

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1416212

Change-Id: Ic8a04251bb1d6b35b0516525fc8ac6eea06c537e

1 files changed, 8 insertions, 9 deletions

diff --git a/media/java/android/media/AudioSystem.java b/media/java/android/media/AudioSystem.java
index 90ec39d1a708..20905380a2f1 100644
--- a/media/java/android/media/AudioSystem.java
+++ b/media/java/android/media/AudioSystem.java
@@ -523,6 +523,7 @@ public class AudioSystem
     /** @hide Media server died. see ErrorCallback */
     public static final int AUDIO_STATUS_SERVER_DIED = 100;
 
+    // all accesses must be synchronized (AudioSystem.class)
     private static ErrorCallback sErrorCallback;
 
     /** @hide
@@ -559,11 +560,9 @@ public class AudioSystem
     @UnsupportedAppUsage
     private static void errorCallbackFromNative(int error)
     {
-        ErrorCallback errorCallback = null;
+        ErrorCallback errorCallback;
         synchronized (AudioSystem.class) {
-            if (sErrorCallback != null) {
-                errorCallback = sErrorCallback;
-            }
+            errorCallback = sErrorCallback;
         }
         if (errorCallback != null) {
             errorCallback.onError(error);
@@ -583,6 +582,7 @@ public class AudioSystem
     //keep in sync with include/media/AudioPolicy.h
     private final static int DYNAMIC_POLICY_EVENT_MIX_STATE_UPDATE = 0;
 
+    // all accesses must be synchronized (AudioSystem.class)
     private static DynamicPolicyCallback sDynPolicyCallback;
 
     /** @hide */
@@ -597,11 +597,9 @@ public class AudioSystem
     @UnsupportedAppUsage
     private static void dynamicPolicyCallbackFromNative(int event, String regId, int val)
     {
-        DynamicPolicyCallback cb = null;
+        DynamicPolicyCallback cb;
         synchronized (AudioSystem.class) {
-            if (sDynPolicyCallback != null) {
-                cb = sDynPolicyCallback;
-            }
+            cb = sDynPolicyCallback;
         }
         if (cb != null) {
             switch(event) {
@@ -645,6 +643,7 @@ public class AudioSystem
                         int activeSource, String packName);
     }
 
+    // all accesses must be synchronized (AudioSystem.class)
     private static AudioRecordingCallback sRecordingCallback;
 
     /** @hide */
@@ -677,7 +676,7 @@ public class AudioSystem
                           int source, int portId, boolean silenced, int[] recordingFormat,
                           AudioEffect.Descriptor[] clientEffects, AudioEffect.Descriptor[] effects,
                           int activeSource) {
-        AudioRecordingCallback cb = null;
+        AudioRecordingCallback cb;
         synchronized (AudioSystem.class) {
             cb = sRecordingCallback;
         }