Move utilities to libs/net
These files used to be in the network stack directory, but the libs
directory is a much more suitable place for them.
Also fix a typo : ConcurrentIntepreter → ConcurrentInterpreter
Also move {FdEvents,Packet}Reader to internal annotations. That's
what they should have been using in the first place anyway.
Note that this does not fix preupload issues reported by
checkstyle to make review easier. The fixes are in a followup
patch to this one.
Test: checkbuild
Change-Id: I675077fd42cbb092c0e6bd56571f2fc022e582fd
diff --git a/staticlibs/device/android/net/util/FdEventsReader.java b/staticlibs/device/android/net/util/FdEventsReader.java
new file mode 100644
index 0000000..a5714aa
--- /dev/null
+++ b/staticlibs/device/android/net/util/FdEventsReader.java
@@ -0,0 +1,269 @@
+/*
+ * 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.
+ */
+
+// TODO : move this and PacketReader to com.android.net.module.util.
+package android.net.util;
+
+import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_ERROR;
+import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT;
+
+import android.os.Handler;
+import android.os.Looper;
+import android.os.MessageQueue;
+import android.system.ErrnoException;
+import android.system.OsConstants;
+import android.util.Log;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+
+
+/**
+ * This class encapsulates the mechanics of registering a file descriptor
+ * with a thread's Looper and handling read events (and errors).
+ *
+ * Subclasses MUST implement createFd() and SHOULD override handlePacket(). They MAY override
+ * onStop() and onStart().
+ *
+ * Subclasses can expect a call life-cycle like the following:
+ *
+ * [1] when a client calls start(), createFd() is called, followed by the onStart() hook if all
+ * goes well. Implementations may override onStart() for additional initialization.
+ *
+ * [2] yield, waiting for read event or error notification:
+ *
+ * [a] readPacket() && handlePacket()
+ *
+ * [b] if (no error):
+ * goto 2
+ * else:
+ * goto 3
+ *
+ * [3] when a client calls stop(), the onStop() hook is called (unless already stopped or never
+ * started). Implementations may override onStop() for additional cleanup.
+ *
+ * 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 MUST only be called from the same thread with which
+ * the Handler constructor argument is associated.
+ *
+ * @param <BufferType> the type of the buffer used to read data.
+ */
+public abstract class FdEventsReader<BufferType> {
+ private static final int FD_EVENTS = EVENT_INPUT | EVENT_ERROR;
+ private static final int UNREGISTER_THIS_FD = 0;
+
+ @NonNull
+ private final Handler mHandler;
+ @NonNull
+ private final MessageQueue mQueue;
+ @NonNull
+ private final BufferType mBuffer;
+ @Nullable
+ private FileDescriptor mFd;
+ private long mPacketsReceived;
+
+ protected static void closeFd(FileDescriptor fd) {
+ try {
+ SocketUtils.closeSocket(fd);
+ } catch (IOException ignored) {
+ }
+ }
+
+ protected FdEventsReader(@NonNull Handler h, @NonNull BufferType buffer) {
+ mHandler = h;
+ mQueue = mHandler.getLooper().getQueue();
+ mBuffer = buffer;
+ }
+
+ @VisibleForTesting
+ @NonNull
+ protected MessageQueue getMessageQueue() {
+ return mQueue;
+ }
+
+ /** Start this FdEventsReader. */
+ public boolean start() {
+ if (!onCorrectThread()) {
+ throw new IllegalStateException("start() called from off-thread");
+ }
+
+ return createAndRegisterFd();
+ }
+
+ /** Stop this FdEventsReader and destroy the file descriptor. */
+ public void stop() {
+ if (!onCorrectThread()) {
+ throw new IllegalStateException("stop() called from off-thread");
+ }
+
+ unregisterAndDestroyFd();
+ }
+
+ @NonNull
+ public Handler getHandler() {
+ return mHandler;
+ }
+
+ protected abstract int recvBufSize(@NonNull BufferType buffer);
+
+ /** Returns the size of the receive buffer. */
+ public int recvBufSize() {
+ return recvBufSize(mBuffer);
+ }
+
+ /**
+ * Get the number of successful calls to {@link #readPacket(FileDescriptor, Object)}.
+ *
+ * <p>A call was successful if {@link #readPacket(FileDescriptor, Object)} returned a value > 0.
+ */
+ 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. The socket MUST be created nonblocking.
+ */
+ @Nullable
+ protected abstract FileDescriptor createFd();
+
+ /**
+ * Implementations MUST return the bytes read or throw an Exception.
+ *
+ * <p>The caller may throw a {@link ErrnoException} with {@link OsConstants#EAGAIN} or
+ * {@link OsConstants#EINTR}, in which case {@link FdEventsReader} will ignore the buffer
+ * contents and respectively wait for further input or retry the read immediately. For all other
+ * exceptions, the {@link FdEventsReader} will be stopped with no more interactions with this
+ * method.
+ */
+ protected abstract int readPacket(@NonNull FileDescriptor fd, @NonNull BufferType buffer)
+ throws Exception;
+
+ /**
+ * Called by the main loop for every packet. Any desired copies of
+ * |recvbuf| should be made in here, as the underlying byte array is
+ * reused across all reads.
+ */
+ protected void handlePacket(@NonNull BufferType recvbuf, int length) {}
+
+ /**
+ * Called by the main loop to log errors. In some cases |e| may be null.
+ */
+ protected void logError(@NonNull String msg, @Nullable Exception e) {}
+
+ /**
+ * Called by start(), if successful, just prior to returning.
+ */
+ protected void onStart() {}
+
+ /**
+ * Called by stop() just prior to returning.
+ */
+ protected void onStop() {}
+
+ private boolean createAndRegisterFd() {
+ if (mFd != null) return true;
+
+ try {
+ mFd = createFd();
+ } catch (Exception e) {
+ logError("Failed to create socket: ", e);
+ closeFd(mFd);
+ mFd = null;
+ }
+
+ if (mFd == null) return false;
+
+ getMessageQueue().addOnFileDescriptorEventListener(
+ mFd,
+ FD_EVENTS,
+ (fd, events) -> {
+ // Always call handleInput() so read/recvfrom are given
+ // a proper chance to encounter a meaningful errno and
+ // perhaps log a useful error message.
+ if (!isRunning() || !handleInput()) {
+ unregisterAndDestroyFd();
+ return UNREGISTER_THIS_FD;
+ }
+ return FD_EVENTS;
+ });
+ onStart();
+ return true;
+ }
+
+ private boolean isRunning() {
+ return (mFd != null) && mFd.valid();
+ }
+
+ // Keep trying to read until we get EAGAIN/EWOULDBLOCK or some fatal error.
+ private boolean handleInput() {
+ while (isRunning()) {
+ final int bytesRead;
+
+ try {
+ bytesRead = readPacket(mFd, mBuffer);
+ if (bytesRead < 1) {
+ if (isRunning()) logError("Socket closed, exiting", null);
+ break;
+ }
+ mPacketsReceived++;
+ } catch (ErrnoException e) {
+ if (e.errno == OsConstants.EAGAIN) {
+ // We've read everything there is to read this time around.
+ return true;
+ } else if (e.errno == OsConstants.EINTR) {
+ continue;
+ } else {
+ if (isRunning()) logError("readPacket error: ", e);
+ break;
+ }
+ } catch (Exception e) {
+ if (isRunning()) logError("readPacket error: ", e);
+ break;
+ }
+
+ try {
+ handlePacket(mBuffer, bytesRead);
+ } catch (Exception e) {
+ logError("handlePacket error: ", e);
+ Log.wtf(FdEventsReader.class.getSimpleName(), "Error handling packet", e);
+ }
+ }
+
+ return false;
+ }
+
+ private void unregisterAndDestroyFd() {
+ if (mFd == null) return;
+
+ getMessageQueue().removeOnFileDescriptorEventListener(mFd);
+ closeFd(mFd);
+ mFd = null;
+ onStop();
+ }
+
+ private boolean onCorrectThread() {
+ return (mHandler.getLooper() == Looper.myLooper());
+ }
+}