1 /* 2 * Copyright (C) 2023 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 com.android.net.module.util.async; 18 19 import android.os.ParcelFileDescriptor; 20 import android.system.StructPollfd; 21 22 import java.io.FileDescriptor; 23 import java.io.IOException; 24 25 /** 26 * Provides access to all relevant OS functions.. 27 * 28 * @hide 29 */ 30 public abstract class OsAccess { 31 /** Closes the given file, suppressing IO exceptions. */ close(ParcelFileDescriptor fd)32 public abstract void close(ParcelFileDescriptor fd); 33 34 /** Returns file name for debugging purposes. */ getFileDebugName(ParcelFileDescriptor fd)35 public abstract String getFileDebugName(ParcelFileDescriptor fd); 36 37 /** Returns inner FileDescriptor instance. */ getInnerFileDescriptor(ParcelFileDescriptor fd)38 public abstract FileDescriptor getInnerFileDescriptor(ParcelFileDescriptor fd); 39 40 /** 41 * Reads available data from the given non-blocking file descriptor. 42 * 43 * Returns zero if there's no data to read at this moment. 44 * Returns -1 if the file has reached its end or the input stream has been closed. 45 * Otherwise returns the number of bytes read. 46 */ read(FileDescriptor fd, byte[] buffer, int pos, int len)47 public abstract int read(FileDescriptor fd, byte[] buffer, int pos, int len) 48 throws IOException; 49 50 /** 51 * Writes data into the given non-blocking file descriptor. 52 * 53 * Returns zero if there's no buffer space to write to at this moment. 54 * Otherwise returns the number of bytes written. 55 */ write(FileDescriptor fd, byte[] buffer, int pos, int len)56 public abstract int write(FileDescriptor fd, byte[] buffer, int pos, int len) 57 throws IOException; 58 monotonicTimeMillis()59 public abstract long monotonicTimeMillis(); setNonBlocking(FileDescriptor fd)60 public abstract void setNonBlocking(FileDescriptor fd) throws IOException; pipe()61 public abstract ParcelFileDescriptor[] pipe() throws IOException; 62 poll(StructPollfd[] fds, int timeoutMs)63 public abstract int poll(StructPollfd[] fds, int timeoutMs) throws IOException; getPollInMask()64 public abstract short getPollInMask(); getPollOutMask()65 public abstract short getPollOutMask(); 66 } 67