Bug 293331 - API to determine when preference settings have been overridden

4 files changed, 271 insertions, 7 deletions

diff --git a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/BundleDefaultPreferences.java b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/BundleDefaultPreferences.java
new file mode 100644
index 000000000..acbf2cd94
--- /dev/null
+++ b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/BundleDefaultPreferences.java
@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright (c) 2009 IBM 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:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.internal.preferences;
+
+import java.util.*;
+import org.eclipse.core.runtime.IPath;
+import org.eclipse.core.runtime.Path;
+import org.eclipse.core.runtime.preferences.*;
+
+/**
+ * This class represents a preference node in the "bundle_defaults" scope. This scope is
+ * used to represent default values which are set by the bundle in either its preference
+ * initializer or in a file included with the bundle. 
+ * 
+ * This differs from the regular default scope because it does not contain values set
+ * by the product preference customization or the command-line.
+ * 
+ * @since 3.3
+ */
+public class BundleDefaultPreferences extends EclipsePreferences {
+
+	private static Set loadedNodes = Collections.synchronizedSet(new HashSet());
+	private String qualifier;
+	private int segmentCount;
+	private IEclipsePreferences loadLevel;
+
+	/*
+	 * Default constructor.
+	 */
+	public BundleDefaultPreferences() {
+		this(null, null);
+	}
+
+	private BundleDefaultPreferences(EclipsePreferences parent, String name) {
+		super(parent, name);
+		// cache the segment count
+		IPath path = new Path(absolutePath());
+		segmentCount = path.segmentCount();
+		if (segmentCount < 2)
+			return;
+
+		// cache the qualifier
+		String scope = path.segment(0);
+		if (BundleDefaultsScope.SCOPE.equals(scope))
+			qualifier = path.segment(1);
+
+		// cache the location
+		if (qualifier == null)
+			return;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.internal.preferences.EclipsePreferences#getLoadLevel()
+	 */
+	protected IEclipsePreferences getLoadLevel() {
+		if (loadLevel == null) {
+			if (qualifier == null)
+				return null;
+			// Make it relative to this node rather than navigating to it from the root.
+			// Walk backwards up the tree starting at this node.
+			// This is important to avoid a chicken/egg thing on startup.
+			IEclipsePreferences node = this;
+			for (int i = 2; i < segmentCount; i++)
+				node = (IEclipsePreferences) node.parent();
+			loadLevel = node;
+		}
+		return loadLevel;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.internal.preferences.EclipsePreferences#isAlreadyLoaded(org.eclipse.core.runtime.preferences.IEclipsePreferences)
+	 */
+	protected boolean isAlreadyLoaded(IEclipsePreferences node) {
+		return loadedNodes.contains(node.name());
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.internal.preferences.EclipsePreferences#loaded()
+	 */
+	protected void loaded() {
+		loadedNodes.add(name());
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.internal.preferences.EclipsePreferences#load()
+	 */
+	protected void load() {
+		// ensure that the same node in the "default" scope is loaded so this one is 
+		// initialized properly
+		String relativePath = DefaultPreferences.getScopeRelativePath(absolutePath());
+		if (relativePath != null) {
+			// touch the node to force a load
+			PreferencesService.getDefault().getRootNode().node(DefaultScope.SCOPE).node(relativePath);
+		}
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.internal.preferences.EclipsePreferences#internalCreate(org.eclipse.core.internal.preferences.EclipsePreferences, java.lang.String, java.lang.Object)
+	 */
+	protected EclipsePreferences internalCreate(EclipsePreferences nodeParent, String nodeName, Object context) {
+		return new BundleDefaultPreferences(nodeParent, nodeName);
+	}
+}
diff --git a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/DefaultPreferences.java b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/DefaultPreferences.java
index c42f904b2..d96f1ab88 100644
--- a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/DefaultPreferences.java
+++ b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/DefaultPreferences.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2004, 2008 IBM Corporation and others.
+ * Copyright (c) 2004, 2009 IBM 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
@@ -18,10 +18,12 @@ import java.util.*;
 import org.eclipse.core.internal.preferences.exchange.IProductPreferencesService;
 import org.eclipse.core.internal.runtime.RuntimeLog;
 import org.eclipse.core.runtime.*;
+import org.eclipse.core.runtime.preferences.BundleDefaultsScope;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
 import org.eclipse.osgi.util.NLS;
 import org.osgi.framework.Bundle;
 import org.osgi.framework.BundleContext;
+import org.osgi.service.prefs.Preferences;
 import org.osgi.util.tracker.ServiceTracker;
 
 /**
@@ -39,6 +41,7 @@ public class DefaultPreferences extends EclipsePreferences {
 	private static Properties productTranslation;
 	private static Properties commandLineCustomization;
 	private EclipsePreferences loadLevel;
+	private Thread initializingThread;
 
 	// cached values
 	private String qualifier;
@@ -229,16 +232,90 @@ public class DefaultPreferences extends EclipsePreferences {
 	 * @see org.eclipse.core.internal.preferences.EclipsePreferences#load()
 	 */
 	protected void load() {
-		loadDefaults();
-	}
-
-	private void loadDefaults() {
-		applyRuntimeDefaults();
-		applyBundleDefaults();
+		setInitializingBundleDefaults();
+		try {
+			applyRuntimeDefaults();
+			applyBundleDefaults();
+		} finally {
+			clearInitializingBundleDefaults();
+		}
 		applyProductDefaults();
 		applyCommandLineDefaults();
 	}
 
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.internal.preferences.EclipsePreferences#internalPut(java.lang.String, java.lang.String)
+	 */
+	protected String internalPut(String key, String newValue) {
+		// set the value in this node
+		String result = super.internalPut(key, newValue);
+
+		// if we are setting the bundle defaults, then set the corresponding value in
+		// the bundle_defaults scope
+		if (isInitializingBundleDefaults()) {
+			String relativePath = getScopeRelativePath(absolutePath());
+			if (relativePath != null) {
+				Preferences node = PreferencesService.getDefault().getRootNode().node(BundleDefaultsScope.SCOPE).node(relativePath);
+				node.put(key, newValue);
+			}
+		}
+		return result;
+	}
+
+	/*
+	 * Set that we are in the middle of initializing the bundle defaults.
+	 * This is stored on the load level so we know where to look when
+	 * we are setting values on sub-nodes.
+	 */
+	private void setInitializingBundleDefaults() {
+		IEclipsePreferences node = getLoadLevel();
+		if (node instanceof DefaultPreferences) {
+			DefaultPreferences loader = (DefaultPreferences) node;
+			loader.initializingThread = Thread.currentThread();
+		}
+	}
+
+	/*
+	 * Clear the bit saying we are in the middle of initializing the bundle defaults.
+	 * This is stored on the load level so we know where to look when
+	 * we are setting values on sub-nodes.
+	 */
+	private void clearInitializingBundleDefaults() {
+		IEclipsePreferences node = getLoadLevel();
+		if (node instanceof DefaultPreferences) {
+			DefaultPreferences loader = (DefaultPreferences) node;
+			loader.initializingThread = null;
+		}
+	}
+
+	/*
+	 * Are we in the middle of initializing defaults from the bundle 
+	 * initializer or found in the bundle itself? Look on the load level in
+	 * case we are in a sub-node.
+	 */
+	private boolean isInitializingBundleDefaults() {
+		IEclipsePreferences node = getLoadLevel();
+		if (node instanceof DefaultPreferences) {
+			DefaultPreferences loader = (DefaultPreferences) node;
+			return loader.initializingThread == Thread.currentThread();
+		}
+		return false;
+	}
+
+	/*
+	 * Return a path which is relative to the scope of this node. 
+	 * e.g. com.example.foo for /instance/com.example.foo
+	 */
+	protected static String getScopeRelativePath(String absolutePath) {
+		// shouldn't happen but handle empty or root
+		if (absolutePath.length() < 2)
+			return null;
+		int index = absolutePath.indexOf('/', 1);
+		if (index == -1 || index + 1 >= absolutePath.length())
+			return null;
+		return absolutePath.substring(index + 1);
+	}
+
 	private Properties loadProperties(URL url) {
 		Properties result = new Properties();
 		if (url == null)
diff --git a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/PreferencesService.java b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/PreferencesService.java
index a563f9876..62df2fc7d 100644
--- a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/PreferencesService.java
+++ b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/PreferencesService.java
@@ -370,6 +370,8 @@ public class PreferencesService implements IPreferencesService {
 	}
 
 	private void initializeDefaultScopes() {
+		defaultScopes.put(BundleDefaultsScope.SCOPE, new BundleDefaultPreferences());
+		root.addChild(BundleDefaultsScope.SCOPE, null);
 		defaultScopes.put(DefaultScope.SCOPE, new DefaultPreferences());
 		root.addChild(DefaultScope.SCOPE, null);
 		defaultScopes.put(InstanceScope.SCOPE, new InstancePreferences());
diff --git a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/BundleDefaultsScope.java b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/BundleDefaultsScope.java
new file mode 100644
index 000000000..bbeb9ab6b
--- /dev/null
+++ b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/BundleDefaultsScope.java
@@ -0,0 +1,74 @@
+/*******************************************************************************
+ * Copyright (c) 2009 IBM 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:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.runtime.preferences;
+
+import org.eclipse.core.internal.preferences.AbstractScope;
+import org.eclipse.core.runtime.IPath;
+
+/**
+ * Object representing the bundle defaults scope in the Eclipse preferences
+ * hierarchy. Can be used as a context for searching for preference
+ * values (in the IPreferencesService APIs) or for determining the 
+ * correct preference node to set values in the store.
+ * <p>
+ * The bundle defaults are the defaults are default values which have
+ * been set either by the bundle's preference initializer or by a customization
+ * file supplied with the bundle.
+ * <p>
+ * Bundle default preferences are not persisted to disk.
+ * </p>
+ * <p>
+ * The path for preferences defined in the bundle defaults scope hierarchy
+ * is as follows: <code>/bundle_defaults/&lt;qualifier&gt;</code>
+ * </p>
+ * <p>
+ * This class is not intended to be subclassed. This class may be instantiated.
+ * </p>
+ * @since 3.3
+ * @noextend This class is not intended to be subclassed by clients.
+ */
+public final class BundleDefaultsScope extends AbstractScope implements IScopeContext {
+
+	/**
+	 * String constant (value of <code>"default"</code>) used for the 
+	 * scope name for the default preference scope.
+	 */
+	public static final String SCOPE = "bundle_defaults"; //$NON-NLS-1$
+
+	/**
+	 * Create and return a new default scope instance.
+	 */
+	public BundleDefaultsScope() {
+		super();
+	}
+
+	/*
+	 * @see org.eclipse.core.runtime.preferences.IScopeContext#getName()
+	 */
+	public String getName() {
+		return SCOPE;
+	}
+
+	/* (non-Javadoc)
+	 * @see org.eclipse.core.runtime.preferences.IScopeContext#getNode(java.lang.String)
+	 */
+	public IEclipsePreferences getNode(String qualifier) {
+		return super.getNode(qualifier);
+	}
+
+	/*
+	 * @see org.eclipse.core.runtime.preferences.IScopeContext#getLocation()
+	 */
+	public IPath getLocation() {
+		// We don't persist defaults so return null.
+		return null;
+	}
+}