/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
package sun.net.www.http;
import java.net.URL;
import java.net.HttpURLConnection;
import java.io.*;
import java.util.StringTokenizer;
import sun.net.ProgressSource;
import sun.net.www.MeteredStream;
/**
* A stream that has the property of being able to be kept alive for
* multiple downloads from the same server.
*
* @author Stephen R. Pietrowicz (NCSA)
* @author Dave Brown
*/
public
class KeepAliveStream extends MeteredStream implements Hurryable {
// instance variables
HttpClient hc;
boolean hurried;
// has this KeepAliveStream been put on the queue for asynchronous cleanup.
protected boolean queuedForCleanup = false;
private static KeepAliveStreamCleaner queue = new KeepAliveStreamCleaner();
private static Thread cleanerThread = null;
private static boolean startCleanupThread;
/**
* Constructor
*/
public KeepAliveStream(InputStream is, ProgressSource pi, int expected, HttpClient hc) {
super(is, pi, expected);
this.hc = hc;
}
/**
* Attempt to cache this connection
*/
public void close() throws IOException {
// If the inputstream is closed already, just return.
if (closed) {
return;
}
// If this stream has already been queued for cleanup.
if (queuedForCleanup) {
return;
}
// Skip past the data that's left in the Inputstream because
// some sort of error may have occurred.
// Do this ONLY if the skip won't block. The stream may have
// been closed at the beginning of a big file and we don't want
// to hang around for nothing. So if we can't skip without blocking
// we just close the socket and, therefore, terminate the keepAlive
// NOTE: Don't close super class
try {
if (expected > count) {
long nskip = (long) (expected - count);
if (nskip <= available()) {
long n = 0;
while (n < nskip) {
nskip = nskip - n;
n = skip(nskip);
}
} else if (expected <= KeepAliveStreamCleaner.MAX_DATA_REMAINING && !hurried) {
//put this KeepAliveStream on the queue so that the data remaining
//on the socket can be cleanup asyncronously.
queueForCleanup(new KeepAliveCleanerEntry(this, hc));
} else {
hc.closeServer();
}
}
if (!closed && !hurried && !queuedForCleanup) {
hc.finished();
}
} finally {
if (pi != null)
pi.finishTracking();
if (!queuedForCleanup) {
// nulling out the underlying inputstream as well as
// httpClient to let gc collect the memories faster
in = null;
hc = null;
closed = true;
}
}
}
/* we explicitly do not support mark/reset */
public boolean markSupported() {
return false;
}
public void mark(int limit) {}
public void reset() throws IOException {
throw new IOException("mark/reset not supported");
}
public synchronized boolean hurry() {
try {
/* CASE 0: we're actually already done */
if (closed || count >= expected) {
return false;
} else if (in.available() < (expected - count)) {
/* CASE I: can't meet the demand */
return false;
} else {
/* CASE II: fill our internal buffer
* Remind: possibly check memory here
*/
byte[] buf = new byte[expected - count];
DataInputStream dis = new DataInputStream(in);
dis.readFully(buf);
in = new ByteArrayInputStream(buf);
hurried = true;
return true;
}
} catch (IOException e) {
// e.printStackTrace();
return false;
}
}
private static synchronized void queueForCleanup(KeepAliveCleanerEntry kace) {
if(queue != null && !kace.getQueuedForCleanup()) {
if (!queue.offer(kace)) {
kace.getHttpClient().closeServer();
return;
}
kace.setQueuedForCleanup();
}
startCleanupThread = (cleanerThread == null);
if (!startCleanupThread) {
if (!cleanerThread.isAlive()) {
startCleanupThread = true;
}
}
if (startCleanupThread) {
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction() {
public Object run() {
// We want to create the Keep-Alive-SocketCleaner in the
// system threadgroup
ThreadGroup grp = Thread.currentThread().getThreadGroup();
ThreadGroup parent = null;
while ((parent = grp.getParent()) != null) {
grp = parent;
}
cleanerThread = new Thread(grp, queue, "Keep-Alive-SocketCleaner");
cleanerThread.setDaemon(true);
cleanerThread.setPriority(Thread.MAX_PRIORITY - 2);
cleanerThread.start();
return null;
}
});
}
}
protected int remainingToRead() {
return expected - count;
}
protected void setClosed() {
in = null;
hc = null;
closed = true;
}
}
class KeepAliveCleanerEntry
{
KeepAliveStream kas;
HttpClient hc;
public KeepAliveCleanerEntry(KeepAliveStream kas, HttpClient hc) {
this.kas = kas;
this.hc = hc;
}
protected KeepAliveStream getKeepAliveStream() {
return kas;
}
protected HttpClient getHttpClient() {
return hc;
}
protected void setQueuedForCleanup() {
kas.queuedForCleanup = true;
}
protected boolean getQueuedForCleanup() {
return kas.queuedForCleanup;
}
}