diff options
Diffstat (limited to 'src/com/trilead/ssh2/StreamGobbler.java')
-rw-r--r-- | src/com/trilead/ssh2/StreamGobbler.java | 229 |
1 files changed, 0 insertions, 229 deletions
diff --git a/src/com/trilead/ssh2/StreamGobbler.java b/src/com/trilead/ssh2/StreamGobbler.java deleted file mode 100644 index e93c388..0000000 --- a/src/com/trilead/ssh2/StreamGobbler.java +++ /dev/null @@ -1,229 +0,0 @@ - -package com.trilead.ssh2; - -import java.io.IOException; -import java.io.InputStream; - -/** - * 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, plattner@trilead.com - * @version $Id: StreamGobbler.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $ - */ - -public class StreamGobbler extends InputStream -{ - class GobblerThread extends Thread - { - 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 GobblerThread t; - - private 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; - t = new GobblerThread(); - t.setDaemon(true); - t.start(); - } - - 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) - { - } - } - - int b = buffer[read_pos++] & 0xff; - - return b; - } - } - - public int available() throws IOException - { - synchronized (synchronizer) - { - if (isClosed) - throw new IOException("This StreamGobbler is closed."); - - return write_pos - read_pos; - } - } - - public int read(byte[] b) throws IOException - { - return read(b, 0, b.length); - } - - public void close() throws IOException - { - synchronized (synchronizer) - { - if (isClosed) - return; - isClosed = true; - isEOF = true; - synchronizer.notifyAll(); - is.close(); - } - } - - 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) - { - } - } - - int avail = write_pos - read_pos; - - avail = (avail > len) ? len : avail; - - System.arraycopy(buffer, read_pos, b, off, avail); - - read_pos += avail; - - return avail; - } - } -} |