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Commit b1b6f7f3 authored by Santiago Seifert's avatar Santiago Seifert
Browse files

Simplify MediaSessionRecord callback invocations 

And add a comment about thread safety for the callback holders.

This change doesn't make user-impacting functional changes.

Bug: 205124386
Test: atest CtsMediaBetterTogetherTestCases CtsMediaHostTestCases
Change-Id: Ifbc97b3e7fdb958922a794afd2416dce62df9cc2
parent 7d782bbb

services/core/java/com/android/server/media/MediaSessionRecord.java

+54 −151
Original line number Diff line number Diff line
@@ -63,7 +63,6 @@ import android.net.Uri; 
import android.os.Binder;

import android.os.Build;

import android.os.Bundle;

import android.os.DeadObjectException;

import android.os.Handler;

import android.os.IBinder;

import android.os.Looper;
@@ -85,7 +84,6 @@ import com.android.server.uri.UriGrantsManagerInternal; 
import java.io.PrintWriter;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.List;

import java.util.NoSuchElementException;

import java.util.concurrent.CopyOnWriteArrayList;
@@ -183,6 +181,9 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
    private final boolean mVolumeAdjustmentForRemoteGroupSessions;



    private final Object mLock = new Object();

    // This field is partially guarded by mLock. Writes and non-atomic iterations (for example:

    // index-based-iterations) must be guarded by mLock. But it is safe to acquire an iterator

    // without acquiring mLock.

    private final CopyOnWriteArrayList<ISessionControllerCallbackHolder>

            mControllerCallbackHolders = new CopyOnWriteArrayList<>();
@@ -770,24 +771,9 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
            }

            playbackState = mPlaybackState;

        }

        Collection<ISessionControllerCallbackHolder> deadCallbackHolders = null;

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

                holder.mCallback.onPlaybackStateChanged(playbackState);

            } catch (DeadObjectException e) {

                if (deadCallbackHolders == null) {

                    deadCallbackHolders = new ArrayList<>();

                }

                deadCallbackHolders.add(holder);

                logCallbackException("Removing dead callback in pushPlaybackStateUpdate", holder,

                        e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushPlaybackStateUpdate", holder, e);

            }

        }

        if (deadCallbackHolders != null) {

            removeControllerHoldersSafely(deadCallbackHolders);

        }

        performOnCallbackHolders(

                "pushPlaybackStateUpdate",

                holder -> holder.mCallback.onPlaybackStateChanged(playbackState));

    }



    private void pushMetadataUpdate() {
@@ -798,23 +784,8 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
            }

            metadata = mMetadata;

        }

        Collection<ISessionControllerCallbackHolder> deadCallbackHolders = null;

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

                holder.mCallback.onMetadataChanged(metadata);

            } catch (DeadObjectException e) {

                if (deadCallbackHolders == null) {

                    deadCallbackHolders = new ArrayList<>();

                }

                deadCallbackHolders.add(holder);

                logCallbackException("Removing dead callback in pushMetadataUpdate", holder, e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushMetadataUpdate", holder, e);

            }

        }

        if (deadCallbackHolders != null) {

            removeControllerHoldersSafely(deadCallbackHolders);

        }

        performOnCallbackHolders(

                "pushMetadataUpdate", holder -> holder.mCallback.onMetadataChanged(metadata));

    }



    private void pushQueueUpdate() {
@@ -825,8 +796,9 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
            }

            toSend = mQueue == null ? null : new ArrayList<>(mQueue);

        }

        Collection<ISessionControllerCallbackHolder> deadCallbackHolders = null;

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

        performOnCallbackHolders(

                "pushQueueUpdate",

                holder -> {

                    ParceledListSlice<QueueItem> parcelableQueue = null;

                    if (toSend != null) {

                        parcelableQueue = new ParceledListSlice<>(toSend);
@@ -834,22 +806,8 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
                        // as onQueueChanged is an async binder call.

                        parcelableQueue.setInlineCountLimit(1);

                    }



            try {

                    holder.mCallback.onQueueChanged(parcelableQueue);

            } catch (DeadObjectException e) {

                if (deadCallbackHolders == null) {

                    deadCallbackHolders = new ArrayList<>();

                }

                deadCallbackHolders.add(holder);

                logCallbackException("Removing dead callback in pushQueueUpdate", holder, e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushQueueUpdate", holder, e);

            }

        }

        if (deadCallbackHolders != null) {

            removeControllerHoldersSafely(deadCallbackHolders);

        }

                });

    }



    private void pushQueueTitleUpdate() {
@@ -860,23 +818,8 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
            }

            queueTitle = mQueueTitle;

        }

        Collection<ISessionControllerCallbackHolder> deadCallbackHolders = null;

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

                holder.mCallback.onQueueTitleChanged(queueTitle);

            } catch (DeadObjectException e) {

                if (deadCallbackHolders == null) {

                    deadCallbackHolders = new ArrayList<>();

                }

                deadCallbackHolders.add(holder);

                logCallbackException("Removing dead callback in pushQueueTitleUpdate", holder, e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushQueueTitleUpdate", holder, e);

            }

        }

        if (deadCallbackHolders != null) {

            removeControllerHoldersSafely(deadCallbackHolders);

        }

        performOnCallbackHolders(

                "pushQueueTitleUpdate", holder -> holder.mCallback.onQueueTitleChanged(queueTitle));

    }



    private void pushExtrasUpdate() {
@@ -887,23 +830,8 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
            }

            extras = mExtras;

        }

        Collection<ISessionControllerCallbackHolder> deadCallbackHolders = null;

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

                holder.mCallback.onExtrasChanged(extras);

            } catch (DeadObjectException e) {

                if (deadCallbackHolders == null) {

                    deadCallbackHolders = new ArrayList<>();

                }

                deadCallbackHolders.add(holder);

                logCallbackException("Removing dead callback in pushExtrasUpdate", holder, e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushExtrasUpdate", holder, e);

            }

        }

        if (deadCallbackHolders != null) {

            removeControllerHoldersSafely(deadCallbackHolders);

        }

        performOnCallbackHolders(

                "pushExtrasUpdate", holder -> holder.mCallback.onExtrasChanged(extras));

    }



    private void pushVolumeUpdate() {
@@ -914,23 +842,8 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
            }

            info = getVolumeAttributes();

        }

        Collection<ISessionControllerCallbackHolder> deadCallbackHolders = null;

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

                holder.mCallback.onVolumeInfoChanged(info);

            } catch (DeadObjectException e) {

                if (deadCallbackHolders == null) {

                    deadCallbackHolders = new ArrayList<>();

                }

                deadCallbackHolders.add(holder);

                logCallbackException("Removing dead callback in pushVolumeUpdate", holder, e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushVolumeUpdate", holder, e);

            }

        }

        if (deadCallbackHolders != null) {

            removeControllerHoldersSafely(deadCallbackHolders);

        }

        performOnCallbackHolders(

                "pushVolumeUpdate", holder -> holder.mCallback.onVolumeInfoChanged(info));

    }



    private void pushEvent(String event, Bundle data) {
@@ -939,23 +852,7 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
                return;

            }

        }

        Collection<ISessionControllerCallbackHolder> deadCallbackHolders = null;

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

                holder.mCallback.onEvent(event, data);

            } catch (DeadObjectException e) {

                if (deadCallbackHolders == null) {

                    deadCallbackHolders = new ArrayList<>();

                }

                deadCallbackHolders.add(holder);

                logCallbackException("Removing dead callback in pushEvent", holder, e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushEvent", holder, e);

            }

        }

        if (deadCallbackHolders != null) {

            removeControllerHoldersSafely(deadCallbackHolders);

        }

        performOnCallbackHolders("pushEvent", holder -> holder.mCallback.onEvent(event, data));

    }



    private void pushSessionDestroyed() {
@@ -966,20 +863,37 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
                return;

            }

        }

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

        performOnCallbackHolders(

                "pushSessionDestroyed",

                holder -> {

                    holder.mCallback.asBinder().unlinkToDeath(holder.mDeathMonitor, 0);

                    holder.mCallback.onSessionDestroyed();

            } catch (NoSuchElementException e) {

                logCallbackException("error unlinking to binder death", holder, e);

            } catch (DeadObjectException e) {

                logCallbackException("Removing dead callback in pushSessionDestroyed", holder, e);

            } catch (RemoteException e) {

                logCallbackException("unexpected exception in pushSessionDestroyed", holder, e);

                });

        // After notifying clear all listeners

        synchronized (mLock) {

            mControllerCallbackHolders.clear();

        }

    }

        // After notifying clear all listeners

        removeControllerHoldersSafely(null);



    private interface ControllerCallbackCall {



        void performOn(ISessionControllerCallbackHolder holder) throws RemoteException;

    }



    private void performOnCallbackHolders(String operationName, ControllerCallbackCall call) {

        ArrayList<ISessionControllerCallbackHolder> deadCallbackHolders = new ArrayList<>();

        for (ISessionControllerCallbackHolder holder : mControllerCallbackHolders) {

            try {

                call.performOn(holder);

            } catch (RemoteException | NoSuchElementException exception) {

                deadCallbackHolders.add(holder);

                logCallbackException(

                        "Exception while executing: " + operationName, holder, exception);

            }

        }

        synchronized (mLock) {

            mControllerCallbackHolders.removeAll(deadCallbackHolders);

        }

    }



    private PlaybackState getStateWithUpdatedPosition() {
@@ -1027,17 +941,6 @@ public class MediaSessionRecord implements IBinder.DeathRecipient, MediaSessionR 
        return -1;

    }



    private void removeControllerHoldersSafely(

            Collection<ISessionControllerCallbackHolder> holders) {

        synchronized (mLock) {

            if (holders == null) {

                mControllerCallbackHolders.clear();

            } else {

                mControllerCallbackHolders.removeAll(holders);

            }

        }

    }



    private PlaybackInfo getVolumeAttributes() {

        int volumeType;

        AudioAttributes attributes;