1 /* 2 * Copyright (C) 2021 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.car.builtin.os; 18 19 import android.annotation.NonNull; 20 import android.annotation.SystemApi; 21 import android.car.builtin.annotation.AddedIn; 22 import android.car.builtin.annotation.PlatformVersion; 23 import android.os.ParcelFileDescriptor; 24 import android.os.SharedMemory; 25 26 import java.io.IOException; 27 28 /** 29 * Helper for {@link SharedMemory}. 30 * 31 * @hide 32 */ 33 @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES) 34 public final class SharedMemoryHelper { SharedMemoryHelper()35 private SharedMemoryHelper() { 36 throw new UnsupportedOperationException(); 37 } 38 39 /** Returns the backing file for the shared memory wrapped in {@code ParcelFileDescriptor}*/ 40 @NonNull 41 @AddedIn(PlatformVersion.TIRAMISU_0) createParcelFileDescriptor( @onNull SharedMemory memory)42 public static ParcelFileDescriptor createParcelFileDescriptor( 43 @NonNull SharedMemory memory) throws IOException { 44 // Must duplicate the file descriptor because it is currently owned by memory, and we also 45 // want the returned ParcelFileDescriptor to own it. 46 return memory.getFdDup(); 47 } 48 } 49