tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 1 | package org.onlab.nio; |
| 2 | |
tom | 2d6d397 | 2014-09-25 22:38:57 -0700 | [diff] [blame] | 3 | import org.onlab.util.Counter; |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 4 | import org.slf4j.Logger; |
| 5 | import org.slf4j.LoggerFactory; |
| 6 | |
| 7 | import java.io.IOException; |
| 8 | import java.nio.ByteBuffer; |
| 9 | import java.nio.channels.ByteChannel; |
| 10 | import java.nio.channels.SelectionKey; |
| 11 | import java.util.ArrayList; |
| 12 | import java.util.List; |
| 13 | |
| 14 | import static com.google.common.base.Preconditions.checkArgument; |
| 15 | import static com.google.common.base.Preconditions.checkNotNull; |
| 16 | import static java.lang.System.currentTimeMillis; |
| 17 | import static java.nio.ByteBuffer.allocateDirect; |
| 18 | |
| 19 | /** |
| 20 | * Bi-directional message stream for transferring messages to & from the |
| 21 | * network via two byte buffers. |
| 22 | * |
| 23 | * @param <M> message type |
| 24 | */ |
| 25 | public abstract class MessageStream<M extends Message> { |
| 26 | |
| 27 | protected Logger log = LoggerFactory.getLogger(getClass()); |
| 28 | |
| 29 | private final IOLoop<M, ?> loop; |
| 30 | private final ByteChannel channel; |
| 31 | private final int maxIdleMillis; |
| 32 | |
| 33 | private final ByteBuffer inbound; |
| 34 | private ByteBuffer outbound; |
| 35 | private SelectionKey key; |
| 36 | |
| 37 | private volatile boolean closed = false; |
| 38 | private volatile boolean writePending; |
| 39 | private volatile boolean writeOccurred; |
| 40 | |
| 41 | private Exception ioError; |
| 42 | private long lastActiveTime; |
| 43 | |
tom | 2d6d397 | 2014-09-25 22:38:57 -0700 | [diff] [blame] | 44 | private final Counter bytesIn = new Counter(); |
| 45 | private final Counter messagesIn = new Counter(); |
| 46 | private final Counter bytesOut = new Counter(); |
| 47 | private final Counter messagesOut = new Counter(); |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 48 | |
| 49 | /** |
| 50 | * Creates a message stream associated with the specified IO loop and |
| 51 | * backed by the given byte channel. |
| 52 | * |
| 53 | * @param loop IO loop |
| 54 | * @param byteChannel backing byte channel |
| 55 | * @param bufferSize size of the backing byte buffers |
| 56 | * @param maxIdleMillis maximum number of millis the stream can be idle |
| 57 | * before it will be closed |
| 58 | */ |
| 59 | protected MessageStream(IOLoop<M, ?> loop, ByteChannel byteChannel, |
| 60 | int bufferSize, int maxIdleMillis) { |
| 61 | this.loop = checkNotNull(loop, "Loop cannot be null"); |
| 62 | this.channel = checkNotNull(byteChannel, "Byte channel cannot be null"); |
| 63 | |
| 64 | checkArgument(maxIdleMillis > 0, "Idle time must be positive"); |
| 65 | this.maxIdleMillis = maxIdleMillis; |
| 66 | |
| 67 | inbound = allocateDirect(bufferSize); |
| 68 | outbound = allocateDirect(bufferSize); |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * Gets a single message from the specified byte buffer; this is |
| 73 | * to be done without manipulating the buffer via flip, reset or clear. |
| 74 | * |
| 75 | * @param buffer byte buffer |
| 76 | * @return read message or null if there are not enough bytes to read |
| 77 | * a complete message |
| 78 | */ |
| 79 | protected abstract M read(ByteBuffer buffer); |
| 80 | |
| 81 | /** |
| 82 | * Puts the specified message into the specified byte buffer; this is |
| 83 | * to be done without manipulating the buffer via flip, reset or clear. |
| 84 | * |
| 85 | * @param message message to be write into the buffer |
| 86 | * @param buffer byte buffer |
| 87 | */ |
| 88 | protected abstract void write(M message, ByteBuffer buffer); |
| 89 | |
| 90 | /** |
| 91 | * Closes the message buffer. |
| 92 | */ |
| 93 | public void close() { |
| 94 | synchronized (this) { |
| 95 | if (closed) { |
| 96 | return; |
| 97 | } |
| 98 | closed = true; |
| 99 | } |
| 100 | |
tom | 2d6d397 | 2014-09-25 22:38:57 -0700 | [diff] [blame] | 101 | bytesIn.freeze(); |
| 102 | bytesOut.freeze(); |
| 103 | messagesIn.freeze(); |
| 104 | messagesOut.freeze(); |
| 105 | |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 106 | loop.removeStream(this); |
| 107 | if (key != null) { |
| 108 | try { |
| 109 | key.cancel(); |
| 110 | key.channel().close(); |
| 111 | } catch (IOException e) { |
| 112 | log.warn("Unable to close stream", e); |
| 113 | } |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | /** |
| 118 | * Indicates whether this buffer has been closed. |
| 119 | * |
| 120 | * @return true if this stream has been closed |
| 121 | */ |
| 122 | public synchronized boolean isClosed() { |
| 123 | return closed; |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Returns the stream IO selection key. |
| 128 | * |
| 129 | * @return socket channel registration selection key |
| 130 | */ |
| 131 | public SelectionKey key() { |
| 132 | return key; |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Binds the selection key to be used for driving IO operations on the stream. |
| 137 | * |
| 138 | * @param key IO selection key |
| 139 | */ |
| 140 | public void setKey(SelectionKey key) { |
| 141 | this.key = key; |
| 142 | this.lastActiveTime = currentTimeMillis(); |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * Returns the IO loop to which this stream is bound. |
| 147 | * |
| 148 | * @return I/O loop used to drive this stream |
| 149 | */ |
| 150 | public IOLoop<M, ?> loop() { |
| 151 | return loop; |
| 152 | } |
| 153 | |
| 154 | /** |
| 155 | * Indicates whether the any prior IO encountered an error. |
| 156 | * |
| 157 | * @return true if a write failed |
| 158 | */ |
| 159 | public boolean hadError() { |
| 160 | return ioError != null; |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * Gets the prior IO error, if one occurred. |
| 165 | * |
| 166 | * @return IO error; null if none occurred |
| 167 | */ |
| 168 | public Exception getError() { |
| 169 | return ioError; |
| 170 | } |
| 171 | |
| 172 | /** |
tom | 7309483 | 2014-09-29 13:47:08 -0700 | [diff] [blame^] | 173 | * Reads, without blocking, a list of messages from the stream. |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 174 | * The list will be empty if there were not messages pending. |
| 175 | * |
| 176 | * @return list of messages or null if backing channel has been closed |
| 177 | * @throws IOException if messages could not be read |
| 178 | */ |
| 179 | public List<M> read() throws IOException { |
| 180 | try { |
| 181 | int read = channel.read(inbound); |
| 182 | if (read != -1) { |
| 183 | // Read the messages one-by-one and add them to the list. |
| 184 | List<M> messages = new ArrayList<>(); |
| 185 | M message; |
| 186 | inbound.flip(); |
| 187 | while ((message = read(inbound)) != null) { |
| 188 | messages.add(message); |
tom | 2d6d397 | 2014-09-25 22:38:57 -0700 | [diff] [blame] | 189 | messagesIn.add(1); |
| 190 | bytesIn.add(message.length()); |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 191 | } |
| 192 | inbound.compact(); |
| 193 | |
| 194 | // Mark the stream with current time to indicate liveness. |
| 195 | lastActiveTime = currentTimeMillis(); |
| 196 | return messages; |
| 197 | } |
| 198 | return null; |
| 199 | |
| 200 | } catch (Exception e) { |
| 201 | throw new IOException("Unable to read messages", e); |
| 202 | } |
| 203 | } |
| 204 | |
| 205 | /** |
| 206 | * Writes the specified list of messages to the stream. |
| 207 | * |
| 208 | * @param messages list of messages to write |
| 209 | * @throws IOException if error occurred while writing the data |
| 210 | */ |
| 211 | public void write(List<M> messages) throws IOException { |
| 212 | synchronized (this) { |
| 213 | // First write all messages. |
| 214 | for (M m : messages) { |
| 215 | append(m); |
| 216 | } |
| 217 | flushUnlessAlreadyPlanningTo(); |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | /** |
| 222 | * Writes the given message to the stream. |
| 223 | * |
| 224 | * @param message message to write |
| 225 | * @throws IOException if error occurred while writing the data |
| 226 | */ |
| 227 | public void write(M message) throws IOException { |
| 228 | synchronized (this) { |
| 229 | append(message); |
| 230 | flushUnlessAlreadyPlanningTo(); |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | // Appends the specified message into the internal buffer, growing the |
| 235 | // buffer if required. |
| 236 | private void append(M message) { |
| 237 | // If the buffer does not have sufficient length double it. |
| 238 | while (outbound.remaining() < message.length()) { |
| 239 | doubleSize(); |
| 240 | } |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 241 | write(message, outbound); |
tom | 2d6d397 | 2014-09-25 22:38:57 -0700 | [diff] [blame] | 242 | messagesOut.add(1); |
| 243 | bytesOut.add(message.length()); |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 244 | } |
| 245 | |
| 246 | // Forces a flush, unless one is planned already. |
| 247 | private void flushUnlessAlreadyPlanningTo() throws IOException { |
| 248 | if (!writeOccurred && !writePending) { |
| 249 | flush(); |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | /** |
| 254 | * Flushes any pending writes. |
| 255 | * |
| 256 | * @throws IOException if flush failed |
| 257 | */ |
| 258 | public void flush() throws IOException { |
| 259 | synchronized (this) { |
| 260 | if (!writeOccurred && !writePending) { |
| 261 | outbound.flip(); |
| 262 | try { |
| 263 | channel.write(outbound); |
| 264 | } catch (IOException e) { |
| 265 | if (!closed && !e.getMessage().equals("Broken pipe")) { |
| 266 | log.warn("Unable to write data", e); |
| 267 | ioError = e; |
| 268 | } |
| 269 | } |
| 270 | lastActiveTime = currentTimeMillis(); |
| 271 | writeOccurred = true; |
| 272 | writePending = outbound.hasRemaining(); |
| 273 | outbound.compact(); |
| 274 | } |
| 275 | } |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * Indicates whether the stream has bytes to be written to the channel. |
| 280 | * |
| 281 | * @return true if there are bytes to be written |
| 282 | */ |
| 283 | boolean isWritePending() { |
| 284 | synchronized (this) { |
| 285 | return writePending; |
| 286 | } |
| 287 | } |
| 288 | |
tom | 2d6d397 | 2014-09-25 22:38:57 -0700 | [diff] [blame] | 289 | |
| 290 | /** |
| 291 | * Indicates whether data has been written but not flushed yet. |
| 292 | * |
| 293 | * @return true if flush is required |
| 294 | */ |
| 295 | boolean isFlushRequired() { |
| 296 | synchronized (this) { |
| 297 | return outbound.position() > 0; |
| 298 | } |
| 299 | } |
| 300 | |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 301 | /** |
| 302 | * Attempts to flush data, internal stream state and channel availability |
| 303 | * permitting. Invoked by the driver I/O loop during handling of writable |
| 304 | * selection key. |
| 305 | * <p/> |
| 306 | * Resets the internal state flags {@code writeOccurred} and |
| 307 | * {@code writePending}. |
| 308 | * |
| 309 | * @throws IOException if implicit flush failed |
| 310 | */ |
| 311 | void flushIfPossible() throws IOException { |
| 312 | synchronized (this) { |
| 313 | writePending = false; |
| 314 | writeOccurred = false; |
| 315 | if (outbound.position() > 0) { |
| 316 | flush(); |
| 317 | } |
| 318 | } |
| 319 | key.interestOps(SelectionKey.OP_READ); |
| 320 | } |
| 321 | |
| 322 | /** |
| 323 | * Attempts to flush data, internal stream state and channel availability |
| 324 | * permitting and if other writes are not pending. Invoked by the driver |
| 325 | * I/O loop prior to entering select wait. Resets the internal |
| 326 | * {@code writeOccurred} state flag. |
| 327 | * |
| 328 | * @throws IOException if implicit flush failed |
| 329 | */ |
| 330 | void flushIfWriteNotPending() throws IOException { |
| 331 | synchronized (this) { |
| 332 | writeOccurred = false; |
| 333 | if (!writePending && outbound.position() > 0) { |
| 334 | flush(); |
| 335 | } |
| 336 | } |
| 337 | if (isWritePending()) { |
| 338 | key.interestOps(key.interestOps() | SelectionKey.OP_WRITE); |
| 339 | } |
| 340 | } |
| 341 | |
| 342 | /** |
| 343 | * Doubles the size of the outbound buffer. |
| 344 | */ |
| 345 | private void doubleSize() { |
| 346 | ByteBuffer newBuffer = allocateDirect(outbound.capacity() * 2); |
| 347 | outbound.flip(); |
| 348 | newBuffer.put(outbound); |
| 349 | outbound = newBuffer; |
| 350 | } |
| 351 | |
| 352 | /** |
| 353 | * Returns the maximum number of milliseconds the stream is allowed |
| 354 | * without any read/write operations. |
| 355 | * |
| 356 | * @return number if millis of permissible idle time |
| 357 | */ |
| 358 | protected int maxIdleMillis() { |
| 359 | return maxIdleMillis; |
| 360 | } |
| 361 | |
| 362 | |
| 363 | /** |
| 364 | * Returns true if the given stream has gone stale. |
| 365 | * |
| 366 | * @return true if the stream is stale |
| 367 | */ |
| 368 | boolean isStale() { |
| 369 | return currentTimeMillis() - lastActiveTime > maxIdleMillis() && key != null; |
| 370 | } |
| 371 | |
tom | 2d6d397 | 2014-09-25 22:38:57 -0700 | [diff] [blame] | 372 | /** |
| 373 | * Returns the inbound bytes counter. |
| 374 | * |
| 375 | * @return inbound bytes counter |
| 376 | */ |
| 377 | public Counter bytesIn() { |
| 378 | return bytesIn; |
| 379 | } |
| 380 | |
| 381 | /** |
| 382 | * Returns the outbound bytes counter. |
| 383 | * |
| 384 | * @return outbound bytes counter |
| 385 | */ |
| 386 | public Counter bytesOut() { |
| 387 | return bytesOut; |
| 388 | } |
| 389 | |
| 390 | /** |
| 391 | * Returns the inbound messages counter. |
| 392 | * |
| 393 | * @return inbound messages counter |
| 394 | */ |
| 395 | public Counter messagesIn() { |
| 396 | return messagesIn; |
| 397 | } |
| 398 | |
| 399 | /** |
| 400 | * Returns the outbound messages counter. |
| 401 | * |
| 402 | * @return outbound messages counter |
| 403 | */ |
| 404 | public Counter messagesOut() { |
| 405 | return messagesOut; |
| 406 | } |
| 407 | |
tom | a708318 | 2014-09-25 21:38:03 -0700 | [diff] [blame] | 408 | } |