From ac3e1dfd9075f049b6af7e0a6efe658f8853960d Mon Sep 17 00:00:00 2001
From: Martin Oberhuber < martin.oberhuber@windriver.com>
Date: Thu, 10 Aug 2006 16:16:55 +0000
Subject: [PATCH] Fix bug 149179 - use Mutex to serialize parallel sftp
requests where necessary
---
.../eclipse/rse/services/ssh/files/Mutex.java | 148 ++++++++++++
.../services/ssh/files/SftpFileService.java | 227 ++++++++++--------
2 files changed, 275 insertions(+), 100 deletions(-)
create mode 100644 rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/Mutex.java
diff --git a/rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/Mutex.java b/rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/Mutex.java
new file mode 100644
index 00000000000..416c914b483
--- /dev/null
+++ b/rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/Mutex.java
@@ -0,0 +1,148 @@
+/*******************************************************************************
+ * Copyright (c) 2006 Wind River Systems, Inc.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ * Martin Oberhuber (Wind River) - initial API and implementation
+ *******************************************************************************/
+
+package org.eclipse.rse.services.ssh.files;
+
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.eclipse.core.runtime.IProgressMonitor;
+
+import org.eclipse.rse.services.ssh.Activator;
+
+/**
+ * A Mutual Exclusion Lock for Threads that need to access a resource
+ * in a serialized manner.
+ *
+ * Usage Example:
+ *
+ * private Mutex fooMutex;
+ * boolean doFooSerialized()(IProgressMonitor monitor) {
+ * if (fooMutex.waitForLock(monitor, 1000)) {
+ * try {
+ * return doFoo();
+ * } finally {
+ * fooMutex.release();
+ * }
+ * }
+ * return false;
+ * }
+ *
+ */
+public class Mutex {
+
+ private boolean fLocked = false;
+ private List fWaitQueue = new LinkedList();
+
+ /**
+ * Try to acquire the lock maintained by this mutex.
+ *
+ * If the thread needs to wait before it can acquire the mutex, it
+ * will wait in a first-come-first-serve fashion. In case a progress
+ * monitor was given, it will be updated and checked for cancel every
+ * second.
+ *
+ * @param monitor Eclipse Progress Monitor. May be null.
+ * @param timeout Maximum wait time given in milliseconds.
+ * @return true if the lock was obtained successfully.
+ */
+ public synchronized boolean waitForLock(IProgressMonitor monitor, long timeout) {
+ if (Thread.interrupted()) {
+ return false;
+ }
+ if (fLocked) {
+ //need to wait for the lock.
+ boolean canceled = false;
+ final Thread myself = Thread.currentThread();
+ try {
+ fWaitQueue.add(myself);
+ Activator.trace("Mutex: added "+myself+", size="+fWaitQueue.size()); //$NON-NLS-1$ //$NON-NLS-2$
+ long start = System.currentTimeMillis();
+ long timeLeft = timeout;
+ long pollTime = (monitor!=null) ? 1000 : timeLeft;
+ long nextProgressUpdate = start+500;
+ while (timeLeft>0 && !canceled) {
+ try {
+ wait(timeLeft > pollTime ? pollTime : timeLeft);
+ Activator.trace("Mutex: wakeup "+myself+" ?"); //$NON-NLS-1$ //$NON-NLS-2$
+ //I'm still in the list, nobody is allowed to take me out!
+ assert !fWaitQueue.isEmpty();
+ if (!fLocked && fWaitQueue.get(0) == myself) {
+ break; //gee it's my turn!
+ }
+ long curTime = System.currentTimeMillis();
+ timeLeft = start + timeout - curTime;
+ if (monitor!=null) {
+ canceled = monitor.isCanceled();
+ if (!canceled && (curTime>nextProgressUpdate)) {
+ monitor.worked(1);
+ nextProgressUpdate+=1000;
+ }
+ }
+ } catch(InterruptedException e) {
+ canceled = true;
+ }
+ }
+ } finally {
+ fWaitQueue.remove(myself);
+ Activator.trace("Mutex: removed "+myself+", size="+fWaitQueue.size()); //$NON-NLS-1$ //$NON-NLS-2$
+ }
+ if (fLocked || canceled) {
+ //we were not able to acquire the lock due to an exception,
+ //or because the wait was canceled.
+ return false;
+ }
+ }
+ //acquire the lock myself now.
+ fLocked = true;
+ return true;
+ }
+
+ /**
+ * Release this mutex's lock.
+ *
+ * May only be called by the same thread that originally acquired
+ * the Mutex.
+ */
+ public synchronized void release() {
+ fLocked=false;
+ if (!fWaitQueue.isEmpty()) {
+ Object nextOneInQueue = fWaitQueue.get(0);
+ Activator.trace("Mutex: releasing "+nextOneInQueue); //$NON-NLS-1$
+ notifyAll();
+ }
+ }
+
+ /**
+ * Return this Mutex's lock status.
+ * @return true if this mutex is currently acquired by a thread.
+ */
+ public synchronized boolean isLocked() {
+ return fLocked;
+ }
+
+ /**
+ * Interrupt all threads waiting for the Lock, causing their
+ * {@link #waitForLock(IProgressMonitor, long)} method to return
+ * false.
+ * This should be called if the resource that the Threads are
+ * contending for, becomes unavailable for some other reason.
+ */
+ public void interruptAll() {
+ Iterator it = fWaitQueue.iterator();
+ while (it.hasNext()) {
+ Thread aThread = (Thread)it.next();
+ aThread.interrupt();
+ }
+ }
+
+}
diff --git a/rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/SftpFileService.java b/rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/SftpFileService.java
index 024f3fa6c3f..9e717c50281 100644
--- a/rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/SftpFileService.java
+++ b/rse/plugins/org.eclipse.rse.services.ssh/src/org/eclipse/rse/services/ssh/files/SftpFileService.java
@@ -49,6 +49,8 @@ public class SftpFileService extends AbstractFileService implements IFileService
private ISshSessionProvider fSessionProvider;
private ChannelSftp fChannelSftp;
private String fUserHome;
+ private Mutex fDirChannelMutex = new Mutex();
+ private long fDirChannelTimeout = 5000; //max.5 seconds to obtain dir channel
// public SftpFileService(SshConnectorService conn) {
// fConnector = conn;
@@ -130,6 +132,7 @@ public class SftpFileService extends AbstractFileService implements IFileService
if (fChannelSftp!=null && fChannelSftp.isConnected()) {
fChannelSftp.disconnect();
}
+ fDirChannelMutex.interruptAll();
fChannelSftp = null;
}
@@ -140,11 +143,15 @@ public class SftpFileService extends AbstractFileService implements IFileService
//the API docs.
SftpHostFile node = null;
SftpATTRS attrs = null;
- try {
- attrs = getChannel("SftpFileService.getFile").stat(remoteParent+'/'+fileName); //$NON-NLS-1$
- Activator.trace("SftpFileService.getFile done"); //$NON-NLS-1$
- } catch(Exception e) {
- Activator.trace("SftpFileService.getFile failed: "+e.toString()); //$NON-NLS-1$
+ if (fDirChannelMutex.waitForLock(monitor, fDirChannelTimeout)) {
+ try {
+ attrs = getChannel("SftpFileService.getFile").stat(remoteParent+'/'+fileName); //$NON-NLS-1$
+ Activator.trace("SftpFileService.getFile done"); //$NON-NLS-1$
+ } catch(Exception e) {
+ Activator.trace("SftpFileService.getFile failed: "+e.toString()); //$NON-NLS-1$
+ } finally {
+ fDirChannelMutex.release();
+ }
}
if (attrs!=null) {
node = makeHostFile(remoteParent, fileName, attrs);
@@ -171,48 +178,52 @@ public class SftpFileService extends AbstractFileService implements IFileService
}
NamePatternMatcher filematcher = new NamePatternMatcher(fileFilter, true, true);
List results = new ArrayList();
- try {
- java.util.Vector vv=getChannel("SftpFileService.internalFetch").ls(parentPath); //$NON-NLS-1$
- for(int ii=0; ii