Mercurial > 510Connectbot
view src/ch/ethz/ssh2/StreamGobbler.java @ 304:abad243cb341 ganymed
add ecdsa key support everywhere
author | Carl Byington <carl@five-ten-sg.com> |
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date | Tue, 29 Jul 2014 20:28:01 -0700 |
parents | 91a31873c42a |
children | 071eccdff8ea |
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/* * Copyright (c) 2006-2011 Christian Plattner. All rights reserved. * Please refer to the LICENSE.txt for licensing details. */ package ch.ethz.ssh2; import java.io.IOException; import java.io.InputStream; import java.io.InterruptedIOException; /** * A <code>StreamGobbler</code> is an InputStream that uses an internal worker * thread to constantly consume input from another InputStream. It uses a buffer * to store the consumed data. The buffer size is automatically adjusted, if needed. * <p/> * This class is sometimes very convenient - if you wrap a session's STDOUT and STDERR * InputStreams with instances of this class, then you don't have to bother about * the shared window of STDOUT and STDERR in the low level SSH-2 protocol, * since all arriving data will be immediatelly consumed by the worker threads. * Also, as a side effect, the streams will be buffered (e.g., single byte * read() operations are faster). * <p/> * Other SSH for Java libraries include this functionality by default in * their STDOUT and STDERR InputStream implementations, however, please be aware * that this approach has also a downside: * <p/> * If you do not call the StreamGobbler's <code>read()</code> method often enough * and the peer is constantly sending huge amounts of data, then you will sooner or later * encounter a low memory situation due to the aggregated data (well, it also depends on the Java heap size). * Joe Average will like this class anyway - a paranoid programmer would never use such an approach. * <p/> * The term "StreamGobbler" was taken from an article called "When Runtime.exec() won't", * see http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html. * * @author Christian Plattner * @version 2.50, 03/15/10 */ public class StreamGobbler extends InputStream { class GobblerThread extends Thread { @Override public void run() { byte[] buff = new byte[8192]; while (true) { try { int avail = is.read(buff); synchronized (synchronizer) { if (avail <= 0) { isEOF = true; synchronizer.notifyAll(); break; } int space_available = buffer.length - write_pos; if (space_available < avail) { /* compact/resize buffer */ int unread_size = write_pos - read_pos; int need_space = unread_size + avail; byte[] new_buffer = buffer; if (need_space > buffer.length) { int inc = need_space / 3; inc = (inc < 256) ? 256 : inc; inc = (inc > 8192) ? 8192 : inc; new_buffer = new byte[need_space + inc]; } if (unread_size > 0) System.arraycopy(buffer, read_pos, new_buffer, 0, unread_size); buffer = new_buffer; read_pos = 0; write_pos = unread_size; } System.arraycopy(buff, 0, buffer, write_pos, avail); write_pos += avail; synchronizer.notifyAll(); } } catch (IOException e) { synchronized (synchronizer) { exception = e; synchronizer.notifyAll(); break; } } } } } private InputStream is; private final Object synchronizer = new Object(); private boolean isEOF = false; private boolean isClosed = false; private IOException exception = null; private byte[] buffer = new byte[2048]; private int read_pos = 0; private int write_pos = 0; public StreamGobbler(InputStream is) { this.is = is; GobblerThread t = new GobblerThread(); t.setDaemon(true); t.start(); } @Override public int read() throws IOException { synchronized (synchronizer) { if (isClosed) throw new IOException("This StreamGobbler is closed."); while (read_pos == write_pos) { if (exception != null) throw exception; if (isEOF) return -1; try { synchronizer.wait(); } catch (InterruptedException e) { throw new InterruptedIOException(); } } return buffer[read_pos++] & 0xff; } } @Override public int available() throws IOException { synchronized (synchronizer) { if (isClosed) throw new IOException("This StreamGobbler is closed."); return write_pos - read_pos; } } @Override public int read(byte[] b) throws IOException { return read(b, 0, b.length); } @Override public void close() throws IOException { synchronized (synchronizer) { if (isClosed) return; isClosed = true; isEOF = true; synchronizer.notifyAll(); is.close(); } } @Override public int read(byte[] b, int off, int len) throws IOException { if (b == null) throw new NullPointerException(); if ((off < 0) || (len < 0) || ((off + len) > b.length) || ((off + len) < 0) || (off > b.length)) throw new IndexOutOfBoundsException(); if (len == 0) return 0; synchronized (synchronizer) { if (isClosed) throw new IOException("This StreamGobbler is closed."); while (read_pos == write_pos) { if (exception != null) throw exception; if (isEOF) return -1; try { synchronizer.wait(); } catch (InterruptedException e) { throw new InterruptedIOException(); } } int avail = write_pos - read_pos; avail = (avail > len) ? len : avail; System.arraycopy(buffer, read_pos, b, off, avail); read_pos += avail; return avail; } } }