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Issue #3018 synchronize in BundleReflections to avoid shutdown deadlock

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Former-commit-id: 781ec3ecd6 [formerly a085b71c81] [formerly c362af04f3 [formerly 7384a2d32ef554362a0693038e9b60a589afb86a]]
Former-commit-id: c362af04f3
Former-commit-id: e1caa66625
This commit is contained in:
Nate Jensen 2014-04-16 16:59:53 -05:00
parent 736c2cc764
commit 1a40bc4824
1 changed files with 49 additions and 1 deletions
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50
cave/com.raytheon.uf.viz.core/src/com/raytheon/uf/viz/core/reflect/BundleReflections.java
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@ -20,11 +20,15 @@
package com.raytheon.uf.viz.core.reflect;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import org.eclipse.core.runtime.FileLocator;
import org.eclipse.osgi.framework.internal.core.AbstractBundle;
import org.eclipse.osgi.framework.internal.core.BundleRepository;
import org.eclipse.osgi.framework.internal.core.Framework;
import org.osgi.framework.Bundle;
import org.osgi.framework.wiring.BundleWiring;
import org.reflections.Reflections;
@ -47,6 +51,7 @@ import org.reflections.util.ConfigurationBuilder;
* ------------- -------- ----------- --------------------------
* Oct 21, 2013 2491 bsteffen Initial creation
* Jan 22, 2014 2062 bsteffen Handle bundles with no wiring.
* Apr 16, 2014 3018 njensen Synchronize against BundleRepository
*
* </pre>
*
@ -58,11 +63,53 @@ public class BundleReflections {
private final Reflections reflections;
@SuppressWarnings("restriction")
public BundleReflections(Bundle bundle, Scanner scanner) throws IOException {
ConfigurationBuilder cb = new ConfigurationBuilder();
BundleWiring bundleWiring = bundle.adapt(BundleWiring.class);
/*
* If BundleReflection's constructor is invoked on a thread other than
* main/UI thread, then there is a possible deadlock if the application
* shuts down while the bundleWiring.getClassloader() call below is
* still going. The BundleRepository of the Framework is the primary
* resource that is in contention in this deadlock scenario, due to the
* BundleRepository being used as a synchronization lock both deep in
* bundleWiring.getClassloader() and in Framework shutdown code.
*
* Therefore to avoid this deadlock, we attempt to get the
* BundleRepository and synchronize against it, ensuring the call to
* getClassLoader() can finish and then release synchronization locks.
*
* If we fail to get the BundleRepository due to access restrictions,
* then we proceed onwards anyway because the odds of the application
* shutting down at the same time as this is still running is low, and
* even if that occurs, the odds are further reduced that the two
* threads will synchronize against the BundleRepository at the same
* time and deadlock.
*/
BundleRepository bundleRepo = null;
if (bundle instanceof AbstractBundle) {
try {
AbstractBundle ab = (AbstractBundle) bundle;
Field bundleRepoField = Framework.getField(Framework.class,
BundleRepository.class, true);
bundleRepo = (BundleRepository) bundleRepoField.get(ab
.getFramework());
} catch (Throwable t) {
// intentionally log to console and proceed anyway
t.printStackTrace();
}
}
if (bundleWiring != null) {
cb.addClassLoader(bundleWiring.getClassLoader());
if (bundleRepo != null) {
synchronized (bundleRepo) {
cb.addClassLoader(bundleWiring.getClassLoader());
}
} else {
cb.addClassLoader(bundleWiring.getClassLoader());
}
cb.addUrls(FileLocator.getBundleFile(bundle).toURI().toURL());
cb.setScanners(scanner);
reflections = cb.build();
@ -87,4 +134,5 @@ public class BundleReflections {
}
return subTypes;
}
}