Hide MediaSession details from MediaSessions clients

This will enable us to use MediaSessions for other streams that also
support volume adjustment (e.g. mirroring sessions), and not just media
sessions. We can later consider renaming the MediaSessions class to
something like VolumeSessions.

Bug: b/362507305
Test: Presubmit, build and verifying regular volume adjustment
Test: funcionality while casting.
Test: adb shell dumpsys activity service SystemUI | grep -A 100 "VolumeDialogControllerImpl state:"
Flag: EXEMPT Non-functional change
Change-Id: I51739d930d7cdb5b93c58394c699d4b6c3c8567c

1 files changed, 43 insertions, 21 deletions

diff --git a/packages/SettingsLib/src/com/android/settingslib/volume/MediaSessions.kt b/packages/SettingsLib/src/com/android/settingslib/volume/MediaSessions.kt
index 10156c404ebf..bac564c7d0f4 100644
--- a/packages/SettingsLib/src/com/android/settingslib/volume/MediaSessions.kt
+++ b/packages/SettingsLib/src/com/android/settingslib/volume/MediaSessions.kt
@@ -20,6 +20,7 @@ import android.content.Intent
 import android.content.pm.PackageManager
 import android.media.MediaMetadata
 import android.media.session.MediaController
+import android.media.session.MediaController.PlaybackInfo
 import android.media.session.MediaSession
 import android.media.session.MediaSessionManager
 import android.media.session.PlaybackState
@@ -98,16 +99,22 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
     }
 
     /** Set volume `level` to remote media `token` */
-    fun setVolume(token: MediaSession.Token, level: Int) {
+    fun setVolume(sessionId: SessionId, volumeLevel: Int) {
+        when (sessionId) {
+            is SessionId.Media -> setMediaSessionVolume(sessionId.token, volumeLevel)
+        }
+    }
+
+    private fun setMediaSessionVolume(token: MediaSession.Token, volumeLevel: Int) {
         val record = mRecords[token]
         if (record == null) {
             Log.w(TAG, "setVolume: No record found for token $token")
             return
         }
         if (D.BUG) {
-            Log.d(TAG, "Setting level to $level")
+            Log.d(TAG, "Setting level to $volumeLevel")
         }
-        record.controller.setVolumeTo(level, 0)
+        record.controller.setVolumeTo(volumeLevel, 0)
     }
 
     private fun onRemoteVolumeChangedH(sessionToken: MediaSession.Token, flags: Int) {
@@ -122,7 +129,7 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
             )
         }
         val token = controller.sessionToken
-        mCallbacks.onRemoteVolumeChanged(token, flags)
+        mCallbacks.onRemoteVolumeChanged(SessionId.from(token), flags)
     }
 
     private fun onUpdateRemoteSessionListH(sessionToken: MediaSession.Token?) {
@@ -158,7 +165,7 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
                 controller.registerCallback(record, mHandler)
             }
             val record = mRecords[token]
-            val remote = isRemote(playbackInfo)
+            val remote = playbackInfo.isRemote()
             if (remote) {
                 updateRemoteH(token, record!!.name, playbackInfo)
                 record.sentRemote = true
@@ -172,7 +179,7 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
                 Log.d(TAG, "Removing " + record.name + " sentRemote=" + record.sentRemote)
             }
             if (record.sentRemote) {
-                mCallbacks.onRemoteRemoved(token)
+                mCallbacks.onRemoteRemoved(SessionId.from(token))
                 record.sentRemote = false
             }
         }
@@ -213,8 +220,8 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
     private fun updateRemoteH(
         token: MediaSession.Token,
         name: String?,
-        pi: MediaController.PlaybackInfo,
-    ) = mCallbacks.onRemoteUpdate(token, name, pi)
+        playbackInfo: PlaybackInfo,
+    ) = mCallbacks.onRemoteUpdate(SessionId.from(token), name, VolumeInfo.from(playbackInfo))
 
     private inner class MediaControllerRecord(val controller: MediaController) :
         MediaController.Callback() {
@@ -225,7 +232,7 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
             return method + " " + controller.packageName + " "
         }
 
-        override fun onAudioInfoChanged(info: MediaController.PlaybackInfo) {
+        override fun onAudioInfoChanged(info: PlaybackInfo) {
             if (D.BUG) {
                 Log.d(
                     TAG,
@@ -235,9 +242,9 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
                         sentRemote),
                 )
             }
-            val remote = isRemote(info)
+            val remote = info.isRemote()
             if (!remote && sentRemote) {
-                mCallbacks.onRemoteRemoved(controller.sessionToken)
+                mCallbacks.onRemoteRemoved(SessionId.from(controller.sessionToken))
                 sentRemote = false
             } else if (remote) {
                 updateRemoteH(controller.sessionToken, name, info)
@@ -301,20 +308,36 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
         }
     }
 
+    /** Opaque id for ongoing sessions that support volume adjustment. */
+    sealed interface SessionId {
+
+        companion object {
+            fun from(token: MediaSession.Token) = Media(token)
+        }
+
+        data class Media(val token: MediaSession.Token) : SessionId
+    }
+
+    /** Holds session volume information. */
+    data class VolumeInfo(val currentVolume: Int, val maxVolume: Int) {
+
+        companion object {
+
+            fun from(playbackInfo: PlaybackInfo) =
+                VolumeInfo(playbackInfo.currentVolume, playbackInfo.maxVolume)
+        }
+    }
+
     /** Callback for remote media sessions */
     interface Callbacks {
         /** Invoked when remote media session is updated */
-        fun onRemoteUpdate(
-            token: MediaSession.Token?,
-            name: String?,
-            pi: MediaController.PlaybackInfo?,
-        )
+        fun onRemoteUpdate(token: SessionId?, name: String?, volumeInfo: VolumeInfo?)
 
         /** Invoked when remote media session is removed */
-        fun onRemoteRemoved(token: MediaSession.Token?)
+        fun onRemoteRemoved(token: SessionId?)
 
         /** Invoked when remote volume is changed */
-        fun onRemoteVolumeChanged(token: MediaSession.Token?, flags: Int)
+        fun onRemoteVolumeChanged(token: SessionId?, flags: Int)
     }
 
     companion object {
@@ -325,12 +348,11 @@ class MediaSessions(context: Context, looper: Looper, callbacks: Callbacks) {
         const val UPDATE_REMOTE_SESSION_LIST: Int = 3
 
         private const val USE_SERVICE_LABEL = false
-
-        private fun isRemote(pi: MediaController.PlaybackInfo?): Boolean =
-            pi != null && pi.playbackType == MediaController.PlaybackInfo.PLAYBACK_TYPE_REMOTE
     }
 }
 
+private fun PlaybackInfo?.isRemote() = this?.playbackType == PlaybackInfo.PLAYBACK_TYPE_REMOTE
+
 private fun MediaController.dump(n: Int, writer: PrintWriter) {
     writer.println("  Controller $n: $packageName")