Bug 444188: Fix concurrent access to listener collectionsI20180515-0800

EclipsePreferences is now thread-safe.

A new test bundle is created to test org.eclipse.equinox.preferences
Moving tests from
org.eclipse.core.tests.internal.preferences.EclipsePreferencesTest is
not done here.


Signed-off-by: Vasili Gulevich <vasili.gulevich@xored.com>
Signed-off-by: Michelle Stolwyk <Michelle.Stolwyk@intersystems.com>
Change-Id: Ie3f264a2b7766e574bf65ca0cba3648ce76ac458

1 files changed, 142 insertions, 0 deletions

diff --git a/bundles/org.eclipse.equinox.preferences.tests/src/org/eclipse/equinox/preferences/tests/EclipsePreferencesTest.java b/bundles/org.eclipse.equinox.preferences.tests/src/org/eclipse/equinox/preferences/tests/EclipsePreferencesTest.java
new file mode 100644
index 000000000..accbd2dcb
--- /dev/null
+++ b/bundles/org.eclipse.equinox.preferences.tests/src/org/eclipse/equinox/preferences/tests/EclipsePreferencesTest.java
@@ -0,0 +1,142 @@
+/*******************************************************************************
+ * Copyright (c) 2018 InterSystems Corporation and others.
+ * 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:
+ *     InterSystems Corporation - tests for Bug 444188
+ *******************************************************************************/
+package org.eclipse.equinox.preferences.tests;
+
+import static org.junit.Assert.assertNotNull;
+
+import java.util.concurrent.CountDownLatch;
+
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.ICoreRunnable;
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.IStatus;
+import org.eclipse.core.runtime.NullProgressMonitor;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.Status;
+import org.eclipse.core.runtime.jobs.Job;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.INodeChangeListener;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.NodeChangeEvent;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences.PreferenceChangeEvent;
+import org.junit.After;
+import org.junit.Test;
+import org.osgi.service.prefs.BackingStoreException;
+import org.osgi.service.prefs.Preferences;
+
+/**
+ * Test suite for class org.eclipse.core.internal.preferences.EclipsePreferences
+ * WARNING: many tests are still located in org.eclipse.core.tests.internal.preferences.EclipsePreferencesTest from eclipse.platform.runtime
+ */
+public class EclipsePreferencesTest {
+
+	/** 
+	 * Concurrent access to listener collection should not lead to exceptions
+	 * @see https://bugs.eclipse.org/bugs/show_bug.cgi?id=444188
+	 */
+	@Test
+	public void testConcurrentPreferenceChangeListener() throws InterruptedException, CoreException {
+		final IEclipsePreferences node = createTestNode();
+		final int runSize = 100000;
+		
+		executeInTwoThreads(new ICoreRunnable() {
+			@Override
+			public void run(IProgressMonitor monitor) throws CoreException {
+				IPreferenceChangeListener listener = new IPreferenceChangeListener() {
+					@Override
+					public void preferenceChange(PreferenceChangeEvent event) {
+					}
+				};
+				for (int i = 0; i < runSize && !monitor.isCanceled(); i++) {
+					node.addPreferenceChangeListener(listener); // Should not throw
+					node.put("x", "y"); // Should not throw
+					node.remove("x"); // Should not throw
+					node.removePreferenceChangeListener(listener); // Should not throw
+				}
+			}
+		});
+	}
+
+	/** 
+	 * Concurrent access to listener collection should not lead to exceptions
+	 * @see https://bugs.eclipse.org/bugs/show_bug.cgi?id=444188
+	 */
+	@Test
+	public void testConcurrentNodeChangeListener() throws InterruptedException, CoreException {
+		final IEclipsePreferences node = createTestNode();
+		final int runSize = 100000;
+		executeInTwoThreads(new ICoreRunnable() {
+			@Override
+			public void run(IProgressMonitor monitor) throws CoreException {
+				INodeChangeListener listener = new INodeChangeListener() {
+
+					@Override
+					public void removed(NodeChangeEvent event) {
+					}
+
+					@Override
+					public void added(NodeChangeEvent event) {
+					}
+				};
+				for (int i = 0; i < runSize && !monitor.isCanceled(); i++) {
+					node.addNodeChangeListener(listener); // Should not throw
+					try {
+						node.node(Thread.currentThread().getName()).removeNode(); // Should not throw
+					} catch (BackingStoreException e) {
+						throw new CoreException(new Status(IStatus.ERROR, "org.eclipse.core.tests.runtime", 0, "", null));
+					}
+					node.removeNodeChangeListener(listener); // Should not throw
+				}
+			}
+		});
+	}
+
+	private static void executeInTwoThreads(final ICoreRunnable runnable) throws InterruptedException, CoreException {
+		final CountDownLatch latch = new CountDownLatch(1);
+		Job job = Job.create("", new ICoreRunnable() {
+			@Override
+			public void run(IProgressMonitor monitor) throws CoreException {
+				latch.countDown();
+				runnable.run(monitor);
+			}
+		});
+		job.schedule();
+		try {
+			latch.await();
+				runnable.run(new NullProgressMonitor());
+		} finally {
+			job.cancel();
+			job.join();
+			IStatus result = job.getResult();
+			assertNotNull("Job is expected to complete", result);
+			if (!result.isOK()) {
+				throw new CoreException(result);
+			}
+		}
+	}
+	
+	@After
+	public void after() throws BackingStoreException {
+		getScopeRoot().removeNode();
+	}
+	
+	private static String getUniqueString() {
+		return System.currentTimeMillis() + "-" + Math.random();
+	}
+
+	private static IEclipsePreferences createTestNode() {
+		return (IEclipsePreferences) getScopeRoot().node(getUniqueString());
+	}
+	
+	private static IEclipsePreferences getScopeRoot() {
+		return (IEclipsePreferences) Platform.getPreferencesService().getRootNode().node("EclipsePreferencesTest");
+	}
+}