Introduce 'user' preference scope located in <user.home>/.eclipse

bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/PreferencesService.java

@@ -39,6 +39,7 @@ public class PreferencesService implements IPreferencesService {
 	private static List<String> DEFAULT_DEFAULT_LOOKUP_ORDER = List.of( //
 			InstanceScope.SCOPE, //
 			ConfigurationScope.SCOPE, //
+			UserScope.SCOPE, //
 			DefaultScope.SCOPE);
 	private static final char EXPORT_ROOT_PREFIX = '!';
 	private static final char BUNDLE_VERSION_PREFIX = '@';
@@ -339,6 +340,8 @@ private void initializeDefaultScopes() {
 		root.addChild(InstanceScope.SCOPE, null);
 		defaultScopes.put(ConfigurationScope.SCOPE, new ConfigurationPreferences());
 		root.addChild(ConfigurationScope.SCOPE, null);
+		defaultScopes.put(UserScope.SCOPE, new UserPreferences());
+		root.addChild(UserScope.SCOPE, null);
 	}
 
 	public IEclipsePreferences createNode(String key) {

bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/UserPreferences.java

@@ -0,0 +1,48 @@
+/*******************************************************************************
+ * Copyright (c) 2023, 2023 Hannes Wellmann and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Hannes Wellmann - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.internal.preferences;
+
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicBoolean;
+import org.eclipse.core.runtime.IPath;
+import org.eclipse.core.runtime.preferences.UserScope;
+
+public class UserPreferences extends SingletonEclipsePreferences {
+
+	// cache which nodes have been loaded from disk
+	private static final Set<String> LOADED_NODES = ConcurrentHashMap.newKeySet();
+	private static final AtomicBoolean INITIALIZED = new AtomicBoolean();
+
+	/**
+	 * Default constructor. Should only be called by #createExecutableExtension.
+	 */
+	public UserPreferences() {
+		this(null, null);
+	}
+
+	private UserPreferences(EclipsePreferences parent, String name) {
+		super(parent, name, LOADED_NODES, INITIALIZED);
+	}
+
+	@Override
+	IPath getBaseLocation() {
+		return UserScope.INSTANCE.getLocation();
+	}
+
+	@Override
+	protected EclipsePreferences internalCreate(EclipsePreferences nodeParent, String nodeName, Object context) {
+		return new UserPreferences(nodeParent, nodeName);
+	}
+}

bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/UserScope.java

@@ -0,0 +1,57 @@
+/*******************************************************************************
+ * Copyright (c) 2023, 2023 Hannes Wellmann and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Hannes Wellmann - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.runtime.preferences;
+
+import org.eclipse.core.internal.preferences.AbstractScope;
+import org.eclipse.core.runtime.IPath;
+
+/**
+ * @since 3.11
+ */
+public class UserScope extends AbstractScope {
+
+	/**
+	 * String constant (value of <code>"user"</code>) used for the scope name for
+	 * the user preference scope.
+	 */
+	public static final String SCOPE = "user"; //$NON-NLS-1$
+
+	private static final IPath USER_HOME_PREFERENCE_LOCATION;
+	static {
+		String userHome = System.getProperty("user.home"); //$NON-NLS-1$
+		USER_HOME_PREFERENCE_LOCATION = IPath.forWindows(userHome).append(".eclipse"); //$NON-NLS-1$
+	}
+
+	/**
+	 * Singleton instance of a User Scope object. Typical usage is:
+	 * <code>UserScope.INSTANCE.getNode(...);</code>
+	 *
+	 * @since 3.4
+	 */
+	public static final IScopeContext INSTANCE = new UserScope();
+
+	private UserScope() { // static use only via INSTANCE
+	}
+
+	@Override
+	public String getName() {
+		return SCOPE;
+	}
+
+	@Override
+	public IPath getLocation() {
+		return USER_HOME_PREFERENCE_LOCATION;
+	}
+
+}