| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.guacamole.tunnel; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Map-like storage for intercepted Guacamole streams. |
| * |
| * @param <T> |
| * The type of object which will produce or consume the data sent over the |
| * intercepted Guacamole stream. Usually, this will be either InputStream |
| * or OutputStream. |
| */ |
| public class InterceptedStreamMap<T extends Closeable> { |
| |
| /** |
| * Logger for this class. |
| */ |
| private static final Logger logger = LoggerFactory.getLogger(InterceptedStreamMap.class); |
| |
| /** |
| * The maximum number of milliseconds to wait for notification that a |
| * stream has closed before explicitly checking for closure ourselves. |
| */ |
| private static final long STREAM_WAIT_TIMEOUT = 1000; |
| |
| /** |
| * Mapping of the indexes of all streams whose associated "blob" and "end" |
| * instructions should be intercepted. |
| */ |
| private final ConcurrentMap<String, InterceptedStream<T>> streams = |
| new ConcurrentHashMap<String, InterceptedStream<T>>(); |
| |
| /** |
| * Closes the given stream, logging any errors that occur during closure. |
| * The monitor of the stream is notified via a single call to notify() once |
| * the attempt to close has been made. |
| * |
| * @param stream |
| * The stream to close and notify. |
| */ |
| private void close(T stream) { |
| |
| // Attempt to close stream |
| try { |
| stream.close(); |
| } |
| catch (IOException e) { |
| logger.warn("Unable to close intercepted stream: {}", e.getMessage()); |
| logger.debug("I/O error prevented closure of intercepted stream.", e); |
| } |
| |
| // Notify waiting threads that the stream has ended |
| synchronized (stream) { |
| stream.notify(); |
| } |
| |
| } |
| |
| /** |
| * Closes the stream object associated with the stream having the given |
| * index, if any, removing it from the map, logging any errors that occur |
| * during closure, and unblocking any in-progress calls to waitFor() for |
| * that stream. If no such stream exists within this map, then this |
| * function has no effect. |
| * |
| * @param index |
| * The index of the stream whose associated stream object should be |
| * closed. |
| * |
| * @return |
| * The stream associated with the given index, if the stream was stored |
| * within this map, or null if no such stream exists. |
| */ |
| public InterceptedStream<T> close(String index) { |
| |
| // Remove associated stream |
| InterceptedStream<T> stream = streams.remove(index); |
| if (stream == null) |
| return null; |
| |
| // Close stream if it exists |
| close(stream.getStream()); |
| return stream; |
| |
| } |
| |
| /** |
| * Closes the given stream, logging any errors that occur during closure, |
| * and unblocking any in-progress calls to waitFor() for the given stream. |
| * If the given stream is stored within this map, it will also be removed. |
| * |
| * @param stream |
| * The stream to close. |
| * |
| * @return |
| * true if the given stream was stored within this map, false |
| * otherwise. |
| */ |
| public boolean close(InterceptedStream<T> stream) { |
| |
| // Remove stream if present |
| boolean wasRemoved = streams.remove(stream.getIndex(), stream); |
| |
| // Close provided stream |
| close(stream.getStream()); |
| |
| return wasRemoved; |
| |
| } |
| |
| /** |
| * Removes and closes all streams stored within this map, logging any errors |
| * that occur during closure, and unblocking any in-progress calls to |
| * waitFor(). |
| */ |
| public void closeAll() { |
| |
| // Close any active streams |
| for (InterceptedStream<T> stream : streams.values()) |
| close(stream.getStream()); |
| |
| // Remove now-useless references |
| streams.clear(); |
| |
| } |
| |
| /** |
| * Blocks until the given stream is closed, or until another stream with |
| * the same index replaces it. |
| * |
| * @param stream |
| * The stream to wait for. |
| */ |
| public void waitFor(InterceptedStream<T> stream) { |
| |
| T underlyingStream = stream.getStream(); |
| |
| // Wait for stream to close |
| synchronized (underlyingStream) { |
| while (streams.get(stream.getIndex()) == stream) { |
| try { |
| underlyingStream.wait(STREAM_WAIT_TIMEOUT); |
| } |
| catch (InterruptedException e) { |
| // Ignore |
| } |
| } |
| } |
| |
| } |
| |
| /** |
| * Returns the stream stored in this map under the given index. |
| * |
| * @param index |
| * The index of the stream to return. |
| * |
| * @return |
| * The stream having the given index, or null if no such stream is |
| * stored within this map. |
| */ |
| public InterceptedStream<T> get(String index) { |
| return streams.get(index); |
| } |
| |
| /** |
| * Adds the given stream to this map, storing it under its associated |
| * index. If another stream already exists within this map having the same |
| * index, that stream will be closed and replaced. |
| * |
| * @param stream |
| * The stream to store within this map. |
| */ |
| public void put(InterceptedStream<T> stream) { |
| |
| // Add given stream to map |
| InterceptedStream<T> oldStream = |
| streams.put(stream.getIndex(), stream); |
| |
| // If a previous stream DID exist, close it |
| if (oldStream != null) |
| close(oldStream.getStream()); |
| |
| } |
| |
| } |