MediaSessionRecord: Clean up codes

This includes following changes
- Remove unused public methods.
- Change the public method signatures not to share internal members
  when it's unncessary.

This is the initial step towards handling media key events via Media2.

Bug: TBD
Test: Build and flash manually
Change-Id: I4140abf26a1ccbc215a9a80ae0ff7636ae5fd698

3 files changed, 34 insertions, 133 deletions

diff --git a/services/core/java/com/android/server/media/MediaSessionRecord.java b/services/core/java/com/android/server/media/MediaSessionRecord.java
index efc7d6fa5560..aa24ed26023a 100644
--- a/services/core/java/com/android/server/media/MediaSessionRecord.java
+++ b/services/core/java/com/android/server/media/MediaSessionRecord.java
@@ -62,7 +62,7 @@ import java.util.List;
  * This is the system implementation of a Session. Apps will interact with the
  * MediaSession wrapper class instead.
  */
-public class MediaSessionRecord implements IBinder.DeathRecipient {
+public class MediaSessionRecord implements IBinder.DeathRecipient, AutoCloseable {
     private static final String TAG = "MediaSessionRecord";
     private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
 
@@ -125,7 +125,7 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
 
     public MediaSessionRecord(int ownerPid, int ownerUid, int userId, String ownerPackageName,
             ISessionCallback cb, String tag, Bundle sessionInfo,
-            MediaSessionService service, Looper handlerLooper) {
+            MediaSessionService service, Looper handlerLooper) throws RemoteException {
         mOwnerPid = ownerPid;
         mOwnerUid = ownerUid;
         mUserId = userId;
@@ -142,6 +142,9 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
         mAudioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);
         mAudioManagerInternal = LocalServices.getService(AudioManagerInternal.class);
         mAudioAttrs = new AudioAttributes.Builder().setUsage(AudioAttributes.USAGE_MEDIA).build();
+
+        // May throw RemoteException if the session app is killed.
+        mSessionCb.mCb.asBinder().linkToDeath(this, 0);
     }
 
     /**
@@ -154,15 +157,6 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
     }
 
     /**
-     * Get the controller binder for the {@link MediaController}.
-     *
-     * @return The controller binder apps talk to.
-     */
-    public ISessionController getControllerBinder() {
-        return mController;
-    }
-
-    /**
      * Get the session token for creating {@link MediaController}.
      *
      * @return The session token.
@@ -181,15 +175,6 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
     }
 
     /**
-     * Get the tag for the session.
-     *
-     * @return The session's tag.
-     */
-    public String getTag() {
-        return mTag;
-    }
-
-    /**
      * Get the intent the app set for their media button receiver.
      *
      * @return The pending intent set by the app or null.
@@ -199,25 +184,6 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
     }
 
     /**
-     * Get this session's flags.
-     *
-     * @return The flags for this session.
-     */
-    public long getFlags() {
-        return mFlags;
-    }
-
-    /**
-     * Check if this session has the specified flag.
-     *
-     * @param flag The flag to check.
-     * @return True if this session has that flag set, false otherwise.
-     */
-    public boolean hasFlag(int flag) {
-        return (mFlags & flag) != 0;
-    }
-
-    /**
      * Get the UID this session was created for.
      *
      * @return The UID for this session.
@@ -267,7 +233,7 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
     public void adjustVolume(String packageName, String opPackageName, int pid, int uid,
             boolean asSystemService, int direction, int flags, boolean useSuggested) {
         int previousFlagPlaySound = flags & AudioManager.FLAG_PLAY_SOUND;
-        if (isPlaybackActive() || hasFlag(MediaSession.FLAG_EXCLUSIVE_GLOBAL_PRIORITY)) {
+        if (checkPlaybackActiveState(true) || isSystemPriority()) {
             flags &= ~AudioManager.FLAG_PLAY_SOUND;
         }
         if (mVolumeType == PlaybackInfo.PLAYBACK_TYPE_LOCAL) {
@@ -360,84 +326,27 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
     }
 
     /**
-     * Get the playback state.
-     *
-     * @return The current playback state.
-     */
-    public PlaybackState getPlaybackState() {
-        return mPlaybackState;
-    }
-
-    /**
-     * Check if the session is currently performing playback.
-     *
-     * @return True if the session is performing playback, false otherwise.
-     */
-    public boolean isPlaybackActive() {
-        int state = mPlaybackState == null ? PlaybackState.STATE_NONE : mPlaybackState.getState();
-        return MediaSession.isActiveState(state);
-    }
-
-    /**
-     * Get the type of playback, either local or remote.
-     *
-     * @return The current type of playback.
-     */
-    public int getPlaybackType() {
-        return mVolumeType;
-    }
-
-    /**
-     * Get the local audio stream being used. Only valid if playback type is
-     * local.
+     * Check if the session's playback active state matches with the expectation. This always return
+     * {@code false} if the playback state is {@code null}, where we cannot know the actual playback
+     * state associated with the session.
      *
-     * @return The audio stream the session is using.
+     * @param expected True if playback is expected to be active. false otherwise.
+     * @return True if the session's playback matches with the expectation. false otherwise.
      */
-    public AudioAttributes getAudioAttributes() {
-        return mAudioAttrs;
-    }
-
-    /**
-     * Get the type of volume control. Only valid if playback type is remote.
-     *
-     * @return The volume control type being used.
-     */
-    public int getVolumeControl() {
-        return mVolumeControlType;
-    }
-
-    /**
-     * Get the max volume that can be set. Only valid if playback type is
-     * remote.
-     *
-     * @return The max volume that can be set.
-     */
-    public int getMaxVolume() {
-        return mMaxVolume;
-    }
-
-    /**
-     * Get the current volume for this session. Only valid if playback type is
-     * remote.
-     *
-     * @return The current volume of the remote playback.
-     */
-    public int getCurrentVolume() {
-        return mCurrentVolume;
+    public boolean checkPlaybackActiveState(boolean expected) {
+        if (mPlaybackState == null) {
+            return false;
+        }
+        return MediaSession.isActiveState(mPlaybackState.getState()) == expected;
     }
 
     /**
-     * Get the volume we'd like it to be set to. This is only valid for a short
-     * while after a call to adjust or set volume.
+     * Get whether the playback is local.
      *
-     * @return The current optimistic volume or -1.
+     * @return {@code true} if the playback is local.
      */
-    public int getOptimisticVolume() {
-        return mOptimisticVolume;
-    }
-
-    public boolean isTransportControlEnabled() {
-        return hasFlag(MediaSession.FLAG_HANDLES_TRANSPORT_CONTROLS);
+    public boolean isPlaybackLocal() {
+        return mVolumeType == PlaybackInfo.PLAYBACK_TYPE_LOCAL;
     }
 
     @Override
@@ -449,21 +358,19 @@ public class MediaSessionRecord implements IBinder.DeathRecipient {
      * Finish cleaning up this session, including disconnecting if connected and
      * removing the death observer from the callback binder.
      */
-    public void onDestroy() {
+    @Override
+    public void close() {
         synchronized (mLock) {
             if (mDestroyed) {
                 return;
             }
+            mSessionCb.mCb.asBinder().unlinkToDeath(this, 0);
             mDestroyed = true;
             mPlaybackState = null;
             mHandler.post(MessageHandler.MSG_DESTROYED);
         }
     }
 
-    public ISessionCallback getCallback() {
-        return mSessionCb.mCb;
-    }
-
     /**
      * Sends media button.
      *
diff --git a/services/core/java/com/android/server/media/MediaSessionService.java b/services/core/java/com/android/server/media/MediaSessionService.java
index 2986dee79143..0f059dba5274 100644
--- a/services/core/java/com/android/server/media/MediaSessionService.java
+++ b/services/core/java/com/android/server/media/MediaSessionService.java
@@ -205,7 +205,7 @@ public class MediaSessionService extends SystemService implements Monitor {
                 Log.w(TAG, "Unknown session updated. Ignoring.");
                 return;
             }
-            if ((record.getFlags() & MediaSession.FLAG_EXCLUSIVE_GLOBAL_PRIORITY) != 0) {
+            if (record.isSystemPriority()) {
                 if (DEBUG_KEY_EVENT) {
                     Log.d(TAG, "Global priority session is updated, active=" + record.isActive());
                 }
@@ -460,12 +460,7 @@ public class MediaSessionService extends SystemService implements Monitor {
             }
         }
 
-        try {
-            session.getCallback().asBinder().unlinkToDeath(session, 0);
-        } catch (Exception e) {
-            // ignore exceptions while destroying a session.
-        }
-        session.onDestroy();
+        session.close();
         mHandler.postSessionsChanged(session.getUserId());
     }
 
@@ -570,10 +565,10 @@ public class MediaSessionService extends SystemService implements Monitor {
             throw new RuntimeException("Session request from invalid user.");
         }
 
-        final MediaSessionRecord session = new MediaSessionRecord(callerPid, callerUid, userId,
-                callerPackageName, cb, tag, sessionInfo, this, mHandler.getLooper());
+        final MediaSessionRecord session;
         try {
-            cb.asBinder().linkToDeath(session, 0);
+            session = new MediaSessionRecord(callerPid, callerUid, userId,
+                    callerPackageName, cb, tag, sessionInfo, this, mHandler.getLooper());
         } catch (RemoteException e) {
             throw new RuntimeException("Media Session owner died prematurely.", e);
         }
diff --git a/services/core/java/com/android/server/media/MediaSessionStack.java b/services/core/java/com/android/server/media/MediaSessionStack.java
index a5e7d8e18005..732563f6e05e 100644
--- a/services/core/java/com/android/server/media/MediaSessionStack.java
+++ b/services/core/java/com/android/server/media/MediaSessionStack.java
@@ -16,7 +16,6 @@
 
 package com.android.server.media;
 
-import android.media.session.MediaController.PlaybackInfo;
 import android.media.session.MediaSession;
 import android.media.session.PlaybackState;
 import android.os.Debug;
@@ -144,7 +143,7 @@ class MediaSessionStack {
      */
     public MediaSessionRecord getMediaSessionRecord(MediaSession.Token sessionToken) {
         for (MediaSessionRecord record : mSessions) {
-            if (Objects.equals(record.getControllerBinder(), sessionToken.getBinder())) {
+            if (Objects.equals(record.getSessionToken(), sessionToken)) {
                 return record;
             }
         }
@@ -230,8 +229,8 @@ class MediaSessionStack {
         MediaSessionRecord mediaButtonSession = null;
         for (MediaSessionRecord session : mSessions) {
             if (uid == session.getUid()) {
-                if (session.getPlaybackState() != null && session.isPlaybackActive() ==
-                        mAudioPlayerStateMonitor.isPlaybackActive(session.getUid())) {
+                if (session.checkPlaybackActiveState(
+                        mAudioPlayerStateMonitor.isPlaybackActive(session.getUid()))) {
                     // If there's a media session whose PlaybackState matches
                     // the audio playback state, return it immediately.
                     return session;
@@ -287,7 +286,7 @@ class MediaSessionStack {
         int size = records.size();
         for (int i = 0; i < size; i++) {
             MediaSessionRecord record = records.get(i);
-            if (record.isPlaybackActive()) {
+            if (record.checkPlaybackActiveState(true)) {
                 mCachedVolumeDefault = record;
                 return record;
             }
@@ -301,7 +300,7 @@ class MediaSessionStack {
         int size = records.size();
         for (int i = 0; i < size; i++) {
             MediaSessionRecord record = records.get(i);
-            if (record.getPlaybackType() == PlaybackInfo.PLAYBACK_TYPE_REMOTE) {
+            if (!record.isPlaybackLocal()) {
                 return record;
             }
         }
@@ -359,7 +358,7 @@ class MediaSessionStack {
                 continue;
             }
 
-            if (session.isPlaybackActive()) {
+            if (session.checkPlaybackActiveState(true)) {
                 result.add(lastPlaybackActiveIndex++, session);
                 lastActiveIndex++;
             } else {