/*
* @(#)StreamDemultiplexor.java 0.3-2 18/06/1999
*
* This file is part of the HTTPClient package
* Copyright (C) 1996-1999 Ronald Tschalr
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307, USA
*
* For questions, suggestions, bug-reports, enhancement-requests etc.
* I may be contacted at:
*
* ronald@innovation.ch
*
*/
package HTTPClient;
import java.io.*;
import java.net.Socket;
import java.util.Vector;
import java.util.Enumeration;
/**
* This class handles the demultiplexing of input stream. This is needed
* for things like keep-alive in HTTP/1.0, persist in HTTP/1.1 and in HTTP-NG.
*
* @version 0.3-2 18/06/1999
* @author Ronald Tschalr
*/
class StreamDemultiplexor implements GlobalConstants
{
/** the protocol were handling request for */
private int Protocol;
/** the connection we're working for */
private HTTPConnection Connection;
/** the input stream to demultiplex */
private ExtBufferedInputStream Stream;
/** the socket this hangs off */
private Socket Sock = null;
/** signals after the closing of which stream to close the socket */
private ResponseHandler MarkedForClose;
/** timer used to close the socket if unused for a given time */
private SocketTimeout.TimeoutEntry Timer = null;
/** timer thread which implements the timers */
private static SocketTimeout TimerThread = null;
/** a Vector to hold the list of response handlers were serving */
private LinkedList RespHandlerList;
/** number of unread bytes in current chunk (if transf-enc == chunked) */
private int chunk_len;
/** the currently set timeout for the socket */
private int cur_timeout = 0;
static
{
TimerThread = new SocketTimeout(60);
TimerThread.start();
}
// Constructors
/**
* a simple contructor.
*
* @param protocol the protocol used on this stream.
* @param sock the socket which we're to demux.
* @param connection the http-connection this socket belongs to.
*/
StreamDemultiplexor(int protocol, Socket sock, HTTPConnection connection)
throws IOException
{
this.Protocol = protocol;
this.Connection = connection;
RespHandlerList = new LinkedList();
init(sock);
}
/**
* Initializes the demultiplexor with a new socket.
*
* @param stream the stream to demultiplex
*/
private void init(Socket sock) throws IOException
{
if (DebugDemux)
System.err.println("Demux: Initializing Stream Demultiplexor (" +
this.hashCode() + ")");
this.Sock = sock;
this.Stream = new ExtBufferedInputStream(sock.getInputStream());
MarkedForClose = null;
chunk_len = -1;
// start a timer to close the socket after 60 seconds
Timer = TimerThread.setTimeout(this);
}
// Methods
/**
* Each Response must register with us.
*/
void register(Response resp_handler, Request req) throws RetryException
{
synchronized(RespHandlerList)
{
if (Sock == null)
throw new RetryException();
RespHandlerList.addToEnd(
new ResponseHandler(resp_handler, req, this));
}
}
/**
* creates an input stream for the response.
*
* @param resp the response structure requesting the stream
* @return an InputStream
*/
RespInputStream getStream(Response resp)
{
ResponseHandler resph;
for (resph = (ResponseHandler) RespHandlerList.enumerate();
resph != null; resph = (ResponseHandler) RespHandlerList.next())
{
if (resph.resp == resp) break;
}
if (resph != null)
return resph.stream;
else
return null;
}
/**
* Restarts the timer thread that will close an unused socket after
* 60 seconds.
*/
void restartTimer()
{
if (Timer != null) Timer.reset();
}
/**
* reads an array of bytes from the master stream.
*/
int read(byte[] b, int off, int len, ResponseHandler resph, int timeout)
throws IOException
{
if (resph.exception != null)
throw (IOException) resph.exception.fillInStackTrace();
if (resph.eof)
return -1;
// read the headers and data for all responses preceding us.
ResponseHandler head;
while ((head = (ResponseHandler) RespHandlerList.getFirst()) != null &&
head != resph)
{
try
{ head.stream.readAll(timeout); }
catch (IOException ioe)
{
if (ioe instanceof InterruptedIOException)
throw ioe;
else
throw (IOException) resph.exception.fillInStackTrace();
}
}
// Now we can read from the stream.
synchronized(this)
{
if (resph.exception != null)
throw (IOException) resph.exception.fillInStackTrace();
if (DebugDemux)
{
if (resph.resp.cd_type != CD_HDRS)
System.err.println("Demux: Reading for stream " +
resph.stream.hashCode() +
" (" + Thread.currentThread() + ")");
}
if (Timer != null) Timer.hyber();
try
{
int rcvd = -1;
if (timeout != cur_timeout)
{
if (DebugDemux)
{
System.err.println("Demux: Setting timeout to " +
timeout + " ms");
}
try
{ Sock.setSoTimeout(timeout); }
catch (Throwable t)
{ }
cur_timeout = timeout;
}
switch (resph.resp.cd_type)
{
case CD_HDRS:
rcvd = Stream.read(b, off, len);
if (rcvd == -1)
throw new EOFException("Premature EOF encountered");
break;
case CD_0:
rcvd = -1;
close(resph);
break;
case CD_CLOSE:
rcvd = Stream.read(b, off, len);
if (rcvd == -1)
close(resph);
break;
case CD_CONTLEN:
int cl = resph.resp.ContentLength;
if (len > cl - resph.stream.count)
len = cl - resph.stream.count;
rcvd = Stream.read(b, off, len);
if (rcvd == -1)
throw new EOFException("Premature EOF encountered");
if (resph.stream.count+rcvd == cl)
close(resph);
break;
case CD_CHUNKED:
if (chunk_len == -1) // it's a new chunk
chunk_len = Codecs.getChunkLength(Stream);
if (chunk_len > 0) // it's data
{
if (len > chunk_len) len = chunk_len;
rcvd = Stream.read(b, off, len);
if (rcvd == -1)
throw new EOFException("Premature EOF encountered");
chunk_len -= rcvd;
if (chunk_len == 0) // got the whole chunk
{
Stream.read(); // CR
Stream.read(); // LF
chunk_len = -1;
}
}
else // the footers (trailers)
{
resph.resp.readTrailers(Stream);
rcvd = -1;
close(resph);
chunk_len = -1;
}
break;
case CD_MP_BR:
byte[] endbndry = resph.getEndBoundary(Stream);
int[] end_cmp = resph.getEndCompiled(Stream);
rcvd = Stream.read(b, off, len);
if (rcvd == -1)
throw new EOFException("Premature EOF encountered");
int ovf = Stream.pastEnd(endbndry, end_cmp);
if (ovf != -1)
{
rcvd -= ovf;
Stream.reset();
close(resph);
}
break;
default:
throw new Error("Internal Error in StreamDemultiplexor: " +
"Invalid cd_type " + resph.resp.cd_type);
}
restartTimer();
return rcvd;
}
catch (InterruptedIOException ie) // don't intercept this one
{
restartTimer();
throw ie;
}
catch (IOException ioe)
{
if (DebugDemux)
{
System.err.print("Demux: (" + Thread.currentThread() + ") ");
ioe.printStackTrace();
}
close(ioe, true);
throw resph.exception; // set by retry_requests
}
catch (ParseException pe)
{
if (DebugDemux)
{
System.err.print("Demux: (" + Thread.currentThread() + ") ");
pe.printStackTrace();
}
close(new IOException(pe.toString()), true);
throw resph.exception; // set by retry_requests
}
}
}
/**
* skips a number of bytes in the master stream. This is done via a
* dummy read, as the socket input stream doesn't like skip()'s.
*/
synchronized long skip(long num, ResponseHandler resph) throws IOException
{
if (resph.exception != null)
throw (IOException) resph.exception.fillInStackTrace();
if (resph.eof)
return 0;
byte[] dummy = new byte[(int) num];
int rcvd = read(dummy, 0, (int) num, resph, 0);
if (rcvd == -1)
return 0;
else
return rcvd;
}
/**
* Determines the number of available bytes.
*/
synchronized int available(ResponseHandler resph) throws IOException
{
int avail = Stream.available();
if (resph == null) return avail;
if (resph.exception != null)
throw (IOException) resph.exception.fillInStackTrace();
if (resph.eof)
return 0;
switch (resph.resp.cd_type)
{
case CD_0:
return 0;
case CD_HDRS:
// this is something of a hack; I could return 0, but then
// if you were waiting for something on a response that
// wasn't first in line (and you didn't try to read the
// other response) you'd wait forever. On the other hand,
// we might be making a false promise here...
return (avail > 0 ? 1 : 0);
case CD_CLOSE:
return avail;
case CD_CONTLEN:
int cl = resph.resp.ContentLength;
cl -= resph.stream.count;
return (avail < cl ? avail : cl);
case CD_CHUNKED:
return avail; // not perfect...
case CD_MP_BR:
return avail; // not perfect...
default:
throw new Error("Internal Error in StreamDemultiplexor: " +
"Invalid cd_type " + resph.resp.cd_type);
}
}
/**
* Closes the socket and all associated streams. If <var>exception</var>
* is not null then all active requests are retried.
*
* <P>There are five ways this method may be activated. 1) if an exception
* occurs during read or write. 2) if the stream is marked for close but
* no responses are outstanding (e.g. due to a timeout). 3) when the
* markedForClose response is closed. 4) if all response streams up until
* and including the markedForClose response have been closed. 5) if this
* demux is finalized.
*
* @param exception the IOException to be sent to the streams.
* @param was_reset if true then the exception is due to a connection
* reset; otherwise it means we generated the exception
* ourselves and this is a "normal" close.
*/
synchronized void close(IOException exception, boolean was_reset)
{
if (Sock == null) // already cleaned up
return;
if (DebugDemux)
System.err.println("Demux: Closing all streams and socket (" +
this.hashCode() + ")");
try
{ Stream.close(); }
catch (IOException ioe) { }
try
{ Sock.close(); }
catch (IOException ioe) { }
Sock = null;
if (Timer != null)
{
Timer.kill();
Timer = null;
}
Connection.DemuxList.remove(this);
// Here comes the tricky part: redo outstanding requests!
if (exception != null)
synchronized(RespHandlerList)
{ retry_requests(exception, was_reset); }
}
/**
* Retries outstanding requests. Well, actually the RetryModule does
* that. Here we just throw a RetryException for each request so that
* the RetryModule can catch and handle them.
*
* @param exception the exception that led to this call.
* @param was_reset this flag is passed to the RetryException and is
* used by the RetryModule to distinguish abnormal closes
* from expected closes.
*/
private void retry_requests(IOException exception, boolean was_reset)
{
RetryException first = null,
prev = null;
ResponseHandler resph = (ResponseHandler) RespHandlerList.enumerate();
while (resph != null)
{
/* if the application is already reading the data then the
* response has already been handled. In this case we must
* throw the real exception.
*/
if (resph.resp.got_headers)
{
resph.exception = exception;
}
else
{
RetryException tmp = new RetryException(exception.getMessage());
if (first == null) first = tmp;
tmp.request = resph.request;
tmp.response = resph.resp;
tmp.exception = exception;
tmp.conn_reset = was_reset;
tmp.first = first;
tmp.addToListAfter(prev);
prev = tmp;
resph.exception = tmp;
}
RespHandlerList.remove(resph);
resph = (ResponseHandler) RespHandlerList.next();
}
}
/**
* Closes the associated stream. If this one has been markedForClose then
* the socket is closed; else closeSocketIfAllStreamsClosed is invoked.
*/
synchronized void close(ResponseHandler resph)
{
if (resph != (ResponseHandler) RespHandlerList.getFirst())
return;
if (DebugDemux)
System.err.println("Demux: Closing stream " +
resph.stream.hashCode() +
" (" + Thread.currentThread() + ")");
resph.eof = true;
RespHandlerList.remove(resph);
if (resph == MarkedForClose)
close(new IOException("Premature end of Keep-Alive"), false);
else
closeSocketIfAllStreamsClosed();
}
/**
* Close the socket if all the streams have been closed.
*
* <P>When a stream reaches eof it is removed from the response handler
* list, but when somebody close()'s the response stream it is just
* marked as such. This means that all responses in the list have either
* not been read at all or only partially read, but they might have been
* close()'d meaning that nobody is interested in the data. So If all the
* response streams up till and including the one markedForClose have
* been close()'d then we can remove them from our list and close the
* socket.
*
* <P>Note: if the response list is emtpy or if no response is
* markedForClose then this method does nothing. Specifically it does
* not close the socket. We only want to close the socket if we've been
* told to do so.
*
* <P>Also note that there might still be responses in the list after
* the markedForClose one. These are due to us having pipelined more
* requests to the server than it's willing to serve on a single
* connection. These requests will be retried if possible.
*/
synchronized void closeSocketIfAllStreamsClosed()
{
synchronized(RespHandlerList)
{
ResponseHandler resph = (ResponseHandler) RespHandlerList.enumerate();
while (resph != null && resph.stream.closed)
{
if (resph == MarkedForClose)
{
// remove all response handlers first
ResponseHandler tmp;
do
{
tmp = (ResponseHandler) RespHandlerList.getFirst();
RespHandlerList.remove(tmp);
}
while (tmp != resph);
// close the socket
close(new IOException("Premature end of Keep-Alive"), false);
return;
}
resph = (ResponseHandler) RespHandlerList.next();
}
}
}
/**
* returns the socket associated with this demux
*/
synchronized Socket getSocket()
{
if (MarkedForClose != null)
return null;
if (Timer != null) Timer.hyber();
return Sock;
}
/**
* Mark this demux to not accept any more request and to close the
* stream after this <var>resp</var>onse or all requests have been
* processed, or close immediately if no requests are registered.
*
* @param response the Response after which the connection should
* be closed.
*/
synchronized void markForClose(Response resp)
{
synchronized(RespHandlerList)
{
if (RespHandlerList.getFirst() == null) // no active request,
{ // so close the socket
close(new IOException("Premature end of Keep-Alive"), false);
return;
}
}
if (Timer != null)
{
Timer.kill();
Timer = null;
}
ResponseHandler resph, lasth = null;
for (resph = (ResponseHandler) RespHandlerList.enumerate();
resph != null; resph = (ResponseHandler) RespHandlerList.next())
{
if (resph.resp == resp) // new resp precedes any others
{
MarkedForClose = resph;
if (DebugDemux)
System.err.println("Demux: stream " +
resp.inp_stream.hashCode() +
" marked for close (" +
Thread.currentThread() + ")");
closeSocketIfAllStreamsClosed();
return;
}
if (MarkedForClose == resph)
return; // already marked for closing after an earlier resp
lasth = resph;
}
if (lasth == null)
return;
MarkedForClose = lasth; // resp == null, so use last resph
closeSocketIfAllStreamsClosed();
if (DebugDemux)
System.err.println("Demux: stream " + lasth.stream.hashCode() +
" marked for close (" +
Thread.currentThread() + ")");
}
/**
* Emergency stop. Closes the socket and notifies the responses that
* the requests are aborted.
*
* @since V0.3
*/
void abort()
{
if (DebugDemux)
System.err.println("Demux: Aborting socket (" +
this.hashCode() + ")");
// notify all responses of abort
synchronized(RespHandlerList)
{
for (ResponseHandler resph =
(ResponseHandler) RespHandlerList.enumerate();
resph != null;
resph = (ResponseHandler) RespHandlerList.next())
{
if (resph.resp.http_resp != null)
resph.resp.http_resp.markAborted();
if (resph.exception == null)
resph.exception = new IOException("Request aborted by user");
}
/* Close the socket.
* Note: this duplicates most of close(IOException, boolean). We
* do *not* call close() because that is synchronized, but we want
* abort() to be asynch.
*/
if (Sock != null)
{
try
{
try
{ Sock.setSoLinger(false, 0); }
catch (Throwable t)
{ }
try
{ Stream.close(); }
catch (IOException ioe) { }
try
{ Sock.close(); }
catch (IOException ioe) { }
Sock = null;
if (Timer != null)
{
Timer.kill();
Timer = null;
}
}
catch (NullPointerException npe)
{ }
Connection.DemuxList.remove(this);
}
}
}
/**
* A safety net to close the connection.
*/
protected void finalize() throws Throwable
{
close((IOException) null, false);
super.finalize();
}
/**
* produces a string.
* @return a string containing the class name and protocol number
*/
public String toString()
{
String prot;
switch (Protocol)
{
case HTTP:
prot = "HTTP"; break;
case HTTPS:
prot = "HTTPS"; break;
case SHTTP:
prot = "SHTTP"; break;
case HTTP_NG:
prot = "HTTP_NG"; break;
default:
throw new Error("HTTPClient Internal Error: invalid protocol " +
Protocol);
}
return getClass().getName() + "[Protocol=" + prot + "]";
}
}
/**
* This thread is used to implement socket timeouts. It keeps a list of
* timer entries and expries them after a given time.
*/
class SocketTimeout extends Thread implements GlobalConstants
{
/**
* This class represents a timer entry. It is used to close an
* inactive socket after n seconds. Once running, the timer may be
* suspended (hyber()), restarted (reset()), or aborted (kill()).
* When the timer expires it invokes markForClose() on the
* associated stream demultipexer.
*/
class TimeoutEntry
{
boolean restart = false,
hyber = false,
alive = true;
StreamDemultiplexor demux;
TimeoutEntry next = null,
prev = null;
TimeoutEntry(StreamDemultiplexor demux)
{
this.demux = demux;
}
void reset()
{
hyber = false;
if (restart) return;
restart = true;
synchronized(time_list)
{
if (!alive) return;
// remove from current position
next.prev = prev;
prev.next = next;
// and add to end of timeout list
next = time_list[current];
prev = time_list[current].prev;
prev.next = this;
next.prev = this;
}
}
void hyber()
{
if (alive) hyber = true;
}
void kill()
{
alive = false;
restart = false;
hyber = false;
synchronized(time_list)
{
if (prev == null) return;
next.prev = prev;
prev.next = next;
prev = null;
}
}
}
private TimeoutEntry[] time_list;
private int current;
SocketTimeout(int secs)
{
super("SocketTimeout");
try { setDaemon(true); }
catch (SecurityException se) { } // Oh well...
setPriority(MAX_PRIORITY);
time_list = new TimeoutEntry[secs];
for (int idx=0; idx<secs; idx++)
{
time_list[idx] = new TimeoutEntry(null);
time_list[idx].next = time_list[idx].prev = time_list[idx];
}
current = 0;
}
public TimeoutEntry setTimeout(StreamDemultiplexor demux)
{
TimeoutEntry entry = new TimeoutEntry(demux);
synchronized(time_list)
{
entry.next = time_list[current];
entry.prev = time_list[current].prev;
entry.prev.next = entry;
entry.next.prev = entry;
}
return entry;
}
/**
* This timer is implemented by sleeping for 1 second and then
* checking the timer list.
*/
public void run()
{
TimeoutEntry marked = null;
while (true)
{
try { sleep(1000L); } catch (InterruptedException ie) { }
synchronized(time_list)
{
// reset all restart flags
for (TimeoutEntry entry = time_list[current].next;
entry != time_list[current];
entry = entry.next)
{
entry.restart = false;
}
current++;
if (current >= time_list.length)
current = 0;
// remove all expired timers
for (TimeoutEntry entry = time_list[current].next;
entry != time_list[current];
entry = entry.next)
{
if (entry.alive && !entry.hyber)
{
TimeoutEntry prev = entry.prev;
entry.kill();
/* put on death row. Note: we must not invoke
* markForClose() here because it is synch'd
* and can therefore lead to a deadlock if that
* thread is trying to do a reset() or kill()
*/
entry.next = marked;
marked = entry;
entry = prev;
}
}
}
while (marked != null)
{
marked.demux.markForClose(null);
marked = marked.next;
}
}
}
}
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