| /* |
| * Copyright 2020 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.media.session; |
| |
| import android.annotation.NonNull; |
| import android.os.Binder; |
| import android.os.IBinder; |
| import android.os.Parcel; |
| import android.os.Parcelable; |
| import android.os.RemoteException; |
| |
| import com.android.internal.annotations.GuardedBy; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.function.Consumer; |
| |
| /** |
| * Binder to receive a list that has a large number of {@link Parcelable} items. |
| * |
| * It's similar to {@link android.content.pm.ParceledListSlice}, but transactions are performed in |
| * the opposite direction. |
| * |
| * @param <T> the type of {@link Parcelable} |
| * @hide |
| */ |
| public class ParcelableListBinder<T extends Parcelable> extends Binder { |
| |
| private static final int SUGGESTED_MAX_IPC_SIZE = IBinder.getSuggestedMaxIpcSizeBytes(); |
| |
| private static final int END_OF_PARCEL = 0; |
| private static final int ITEM_CONTINUED = 1; |
| |
| private final Consumer<List<T>> mConsumer; |
| |
| private final Object mLock = new Object(); |
| |
| @GuardedBy("mLock") |
| private final List<T> mList = new ArrayList<>(); |
| |
| @GuardedBy("mLock") |
| private int mCount; |
| |
| @GuardedBy("mLock") |
| private boolean mConsumed; |
| |
| /** |
| * Creates an instance. |
| * |
| * @param consumer a consumer that consumes the list received |
| */ |
| public ParcelableListBinder(@NonNull Consumer<List<T>> consumer) { |
| mConsumer = consumer; |
| } |
| |
| @Override |
| protected boolean onTransact(int code, Parcel data, Parcel reply, int flags) |
| throws RemoteException { |
| if (code != FIRST_CALL_TRANSACTION) { |
| return super.onTransact(code, data, reply, flags); |
| } |
| List<T> listToBeConsumed; |
| synchronized (mLock) { |
| if (mConsumed) { |
| return false; |
| } |
| int i = mList.size(); |
| if (i == 0) { |
| mCount = data.readInt(); |
| } |
| while (i < mCount && data.readInt() != END_OF_PARCEL) { |
| mList.add(data.readParcelable(null)); |
| i++; |
| } |
| if (i >= mCount) { |
| listToBeConsumed = mList; |
| mConsumed = true; |
| } else { |
| listToBeConsumed = null; |
| } |
| } |
| if (listToBeConsumed != null) { |
| mConsumer.accept(listToBeConsumed); |
| } |
| return true; |
| } |
| |
| /** |
| * Sends a list of {@link Parcelable} to a binder. |
| * |
| * @param binder a binder interface backed by {@link ParcelableListBinder} |
| * @param list a list to send |
| */ |
| public static <T extends Parcelable> void send(@NonNull IBinder binder, @NonNull List<T> list) |
| throws RemoteException { |
| int count = list.size(); |
| int i = 0; |
| do { |
| Parcel data = Parcel.obtain(); |
| Parcel reply = Parcel.obtain(); |
| if (i == 0) { |
| data.writeInt(count); |
| } |
| while (i < count && data.dataSize() < SUGGESTED_MAX_IPC_SIZE) { |
| data.writeInt(ITEM_CONTINUED); |
| data.writeParcelable(list.get(i), 0); |
| i++; |
| } |
| if (i < count) { |
| data.writeInt(END_OF_PARCEL); |
| } |
| binder.transact(FIRST_CALL_TRANSACTION, data, reply, 0); |
| reply.recycle(); |
| data.recycle(); |
| } while (i < count); |
| } |
| } |