| /* |
| * Copyright (C) 2016 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.net.util; |
| |
| import android.annotation.Nullable; |
| import android.system.ErrnoException; |
| import android.system.Os; |
| import android.system.OsConstants; |
| |
| import libcore.io.IoBridge; |
| |
| import java.io.FileDescriptor; |
| import java.io.InterruptedIOException; |
| import java.io.IOException; |
| |
| |
| /** |
| * A thread that reads from a socket and passes the received packets to a |
| * subclass's handlePacket() method. The packet receive buffer is recycled |
| * on every read call, so subclasses should make any copies they would like |
| * inside their handlePacket() implementation. |
| * |
| * All public methods may be called from any thread. |
| * |
| * @hide |
| */ |
| public abstract class BlockingSocketReader { |
| public static final int DEFAULT_RECV_BUF_SIZE = 2 * 1024; |
| |
| private final byte[] mPacket; |
| private final Thread mThread; |
| private volatile FileDescriptor mSocket; |
| private volatile boolean mRunning; |
| private volatile long mPacketsReceived; |
| |
| // Make it slightly easier for subclasses to properly close a socket |
| // without having to know this incantation. |
| public static final void closeSocket(@Nullable FileDescriptor fd) { |
| try { |
| IoBridge.closeAndSignalBlockedThreads(fd); |
| } catch (IOException ignored) {} |
| } |
| |
| protected BlockingSocketReader() { |
| this(DEFAULT_RECV_BUF_SIZE); |
| } |
| |
| protected BlockingSocketReader(int recvbufsize) { |
| if (recvbufsize < DEFAULT_RECV_BUF_SIZE) { |
| recvbufsize = DEFAULT_RECV_BUF_SIZE; |
| } |
| mPacket = new byte[recvbufsize]; |
| mThread = new Thread(() -> { mainLoop(); }); |
| } |
| |
| public final boolean start() { |
| if (mSocket != null) return false; |
| |
| try { |
| mSocket = createSocket(); |
| } catch (Exception e) { |
| logError("Failed to create socket: ", e); |
| return false; |
| } |
| |
| if (mSocket == null) return false; |
| |
| mRunning = true; |
| mThread.start(); |
| return true; |
| } |
| |
| public final void stop() { |
| mRunning = false; |
| closeSocket(mSocket); |
| mSocket = null; |
| } |
| |
| public final boolean isRunning() { return mRunning; } |
| |
| public final long numPacketsReceived() { return mPacketsReceived; } |
| |
| /** |
| * Subclasses MUST create the listening socket here, including setting |
| * all desired socket options, interface or address/port binding, etc. |
| */ |
| protected abstract FileDescriptor createSocket(); |
| |
| /** |
| * Called by the main loop for every packet. Any desired copies of |
| * |recvbuf| should be made in here, and the underlying byte array is |
| * reused across all reads. |
| */ |
| protected void handlePacket(byte[] recvbuf, int length) {} |
| |
| /** |
| * Called by the main loop to log errors. In some cases |e| may be null. |
| */ |
| protected void logError(String msg, Exception e) {} |
| |
| /** |
| * Called by the main loop just prior to exiting. |
| */ |
| protected void onExit() {} |
| |
| private final void mainLoop() { |
| while (isRunning()) { |
| final int bytesRead; |
| |
| try { |
| // Blocking read. |
| // TODO: See if this can be converted to recvfrom. |
| bytesRead = Os.read(mSocket, mPacket, 0, mPacket.length); |
| if (bytesRead < 1) { |
| if (isRunning()) logError("Socket closed, exiting", null); |
| break; |
| } |
| mPacketsReceived++; |
| } catch (ErrnoException e) { |
| if (e.errno != OsConstants.EINTR) { |
| if (isRunning()) logError("read error: ", e); |
| break; |
| } |
| continue; |
| } catch (IOException ioe) { |
| if (isRunning()) logError("read error: ", ioe); |
| continue; |
| } |
| |
| try { |
| handlePacket(mPacket, bytesRead); |
| } catch (Exception e) { |
| logError("Unexpected exception: ", e); |
| break; |
| } |
| } |
| |
| stop(); |
| onExit(); |
| } |
| } |