[WIP] Remove filesystem plugin

Linked resource for .project works more reliably

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/FixDotProjectPathResourceListener.java

@@ -0,0 +1,103 @@
+/*******************************************************************************
+ * Copyright (c) 2023 Red Hat Inc. and others.
+ * All rights reserved. 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
+ *******************************************************************************/
+package org.eclipse.jdt.ls.core.internal;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.BasicFileAttributeView;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.time.Instant;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.eclipse.core.internal.events.ILifecycleListener;
+import org.eclipse.core.internal.events.LifecycleEvent;
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.resources.IProject;
+import org.eclipse.core.resources.IProjectDescription;
+import org.eclipse.core.resources.IResource;
+import org.eclipse.core.resources.IResourceChangeEvent;
+import org.eclipse.core.resources.IResourceChangeListener;
+import org.eclipse.core.resources.WorkspaceJob;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.ICoreRunnable;
+import org.eclipse.jdt.ls.core.internal.managers.ProjectsManager;
+
+public class FixDotProjectPathResourceListener implements IResourceChangeListener, ILifecycleListener {
+
+	private Map<IProject, Instant> createdProjects = new HashMap<>();
+
+	@Override
+	public void resourceChanged(IResourceChangeEvent event) {
+		if (ProjectsManager.generatesMetadataFilesAtProjectRoot() || event.getDelta() == null) {
+			return;
+		}
+		try {
+			event.getDelta().accept(delta -> {
+				if (delta.getResource() instanceof IProject project && //
+					project.isOpen() && //
+					createdProjects.containsKey(project)) {
+					Instant projectCreation = createdProjects.remove(project);
+					Path dotProjectOnDisk = project.getLocation().append(IProjectDescription.DESCRIPTION_FILE_NAME).toPath();
+					try {
+						BasicFileAttributes attributes = Files.getFileAttributeView(dotProjectOnDisk, BasicFileAttributeView.class).readAttributes();
+						if (attributes.creationTime().toInstant().isAfter(projectCreation)) {
+							// cannot link to resource in current workspace task, plan it next
+							WorkspaceJob.createSystem("Use linked .project for " + project, (ICoreRunnable) (monitor -> {
+								ProjectsManager.linkDotProject(project);
+								ProjectsManager.linkResources(project);
+							})).schedule();
+						}
+					} catch (IOException ex) {
+						JavaLanguageServerPlugin.logException(ex);
+					}
+				}
+				return delta.getResource().getType() == IResource.ROOT;
+			});
+		} catch (CoreException e) {
+			JavaLanguageServerPlugin.logException(e);
+		}
+	}
+
+	@Override
+	public void handleEvent(LifecycleEvent event) throws CoreException {
+		if (event.kind == LifecycleEvent.PRE_PROJECT_CREATE) {
+			if (event.resource instanceof IProject project) {
+				createdProjects.put(project, Instant.now());
+			}
+		} else if (event.kind == LifecycleEvent.PRE_REFRESH) {
+			unlinkIfLocal(event.resource);
+		}
+	}
+
+	private void unlinkIfLocal(IResource resource) {
+		if (resource instanceof IProject project && project.isOpen()) { 
+			try {
+				Arrays.stream(project.members())
+					.filter(IFile.class::isInstance)
+					.map(IFile.class::cast)
+					.filter(IFile::isLinked)
+					.filter(file -> file.getProject().getLocation().append(file.getProjectRelativePath()).toFile().isFile())
+					.forEach(file -> {
+						try {
+							file.delete(false, false, null);
+						} catch (CoreException e) {
+							JavaLanguageServerPlugin.logException(e);
+						}
+					});
+			} catch (CoreException e) {
+				JavaLanguageServerPlugin.logException(e);
+			}
+		}
+	}
+
+}

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JavaLanguageServerPlugin.java

@@ -28,8 +28,10 @@
 
 import org.apache.commons.lang3.StringUtils;
 import org.eclipse.core.internal.net.ProxySelector;
+import org.eclipse.core.internal.resources.Workspace;
 import org.eclipse.core.net.proxy.IProxyData;
 import org.eclipse.core.net.proxy.IProxyService;
+import org.eclipse.core.resources.IResourceChangeEvent;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IStatus;
@@ -113,7 +115,7 @@ public class JavaLanguageServerPlugin extends Plugin {
 	private ProjectsManager projectsManager;
 	private DigestStore digestStore;
 	private ContentProviderManager contentProviderManager;
-
+	private FixDotProjectPathResourceListener fixDotProjectListener;
 	private BaseJDTLanguageServer protocol;
 
 	private PreferenceManager preferenceManager;
@@ -155,6 +157,9 @@ public void start(BundleContext bundleContext) throws Exception {
 			preferenceManager = new StandardPreferenceManager();
 			projectsManager = new StandardProjectsManager(preferenceManager);
 		}
+		fixDotProjectListener = new FixDotProjectPathResourceListener();
+		ResourcesPlugin.getWorkspace().addResourceChangeListener(fixDotProjectListener, IResourceChangeEvent.POST_CHANGE);
+		((Workspace)ResourcesPlugin.getWorkspace()).addLifecycleListener(fixDotProjectListener);
 		digestStore = new DigestStore(getStateLocation().toFile());
 		try {
 			ResourcesPlugin.getWorkspace().addSaveParticipant(IConstants.PLUGIN_ID, projectsManager);
@@ -365,6 +370,7 @@ public void stop(BundleContext bundleContext) throws Exception {
 		JavaLanguageServerPlugin.pluginInstance = null;
 		JavaLanguageServerPlugin.context = null;
 		ResourcesPlugin.getWorkspace().removeSaveParticipant(IConstants.PLUGIN_ID);
+		ResourcesPlugin.getWorkspace().removeResourceChangeListener(fixDotProjectListener);
 		projectsManager = null;
 		contentProviderManager = null;
 		languageServer = null;

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/managers/ProjectsManager.java

@@ -19,6 +19,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.net.URI;
+import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -486,6 +487,25 @@ public static void linkResources(IProject project) throws CoreException {
 		}
 	}
 
+	public static void linkDotProject(IProject project) throws CoreException {
+		IFile dotProject = project.getFile(IProjectDescription.DESCRIPTION_FILE_NAME);
+		if (dotProject.isLinked()) {
+			return;
+		}
+		File targetDiskFile = getMetaDataFilePath(project.getName(), dotProject.getProjectRelativePath()).toFile();
+		if (!targetDiskFile.exists()) {
+			try {
+				targetDiskFile.getParentFile().mkdirs();
+				Files.copy(dotProject.getLocation().toPath(), targetDiskFile.toPath());
+			} catch (Exception ex) {
+				throw new CoreException(Status.error(targetDiskFile + " cannot be created", ex)); //$NON-NLS-1$
+			}
+		}
+		File sourceDiskFile = dotProject.getLocation().toFile();
+		dotProject.createLink(IPath.fromFile(targetDiskFile), IResource.FORCE | IResource.REPLACE, null);
+		sourceDiskFile.delete();
+	}
+
 	@Override
 	public Job updateProject(IProject project, boolean force) {
 		if (project == null || ProjectUtils.isInternalBuildSupport(BuildSupportManager.find(project).orElse(null))) {