rename to CLanguageServerEnableCache and enable on opening

bundles/org.eclipse.cdt.lsp/src/org/eclipse/cdt/lsp/internal/editor/EditorPreferredOptions.java

@@ -18,7 +18,7 @@
 import org.eclipse.cdt.lsp.editor.EditorMetadata;
 import org.eclipse.cdt.lsp.editor.EditorOptions;
 import org.eclipse.cdt.lsp.editor.LanguageServerEnable;
-import org.eclipse.cdt.lsp.internal.server.URICache;
+import org.eclipse.cdt.lsp.internal.server.CLanguageServerEnableCache;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences.IPreferenceChangeListener;
 import org.eclipse.core.runtime.preferences.IScopeContext;
@@ -30,7 +30,7 @@ public EditorPreferredOptions(EditorMetadata metadata, String qualifier, IScopeC
 			LanguageServerEnable enable) {
 		super(metadata, qualifier, scopes);
 		this.enable = enable;
-		this.addPreferenceChangedListener(URICache.getInstance());
+		this.addPreferenceChangedListener(CLanguageServerEnableCache.getInstance());
 	}
 
 	@Override

bundles/org.eclipse.cdt.lsp/src/org/eclipse/cdt/lsp/internal/server/URICache.java → bundles/org.eclipse.cdt.lsp/src/org/eclipse/cdt/lsp/internal/server/CLanguageServerEnableCache.java

@@ -20,6 +20,7 @@
 
 import org.eclipse.cdt.internal.core.LRUCache;
 import org.eclipse.cdt.lsp.editor.EditorMetadata;
+import org.eclipse.cdt.lsp.util.LspUtils;
 import org.eclipse.core.internal.content.ContentTypeManager;
 import org.eclipse.core.runtime.content.IContentTypeManager.ContentTypeChangeEvent;
 import org.eclipse.core.runtime.content.IContentTypeManager.IContentTypeChangeListener;
@@ -31,23 +32,28 @@
 import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.editors.text.TextEditor;
 import org.eclipse.ui.internal.genericeditor.ExtensionBasedTextEditor;
 
 /**
- * Caches the enable status for a given resource URI. Used by {@link HasLanguageServerPropertyTester#test(Object, String, Object[], Object)}
- * The cache is getting cleared: on changes in the C/C++ content types or the prefer LSP editor option has been changed (workspace or project level).
+ * Caches the Language Server enable for a given resource URI. Used by {@link HasLanguageServerPropertyTester#test(Object, String, Object[], Object)}
+ * The cache is getting cleared:
+ * - on changes in the C/C++ related content types or
+ * - the prefer LSP editor option has been changed (workspace or project level) or
+ * - the LS has been stopped.
  * A resource URI shall be removed from the cache if it's getting closed in the editor.
+ * The enable Language Server is cached when the file has been opened in the LSP based C/C++ editor.
  */
-public final class URICache
+public final class CLanguageServerEnableCache
 		implements IPreferenceChangeListener, IContentTypeChangeListener, IPartListener, IWindowListener {
 	private static final String C_SOURCE = "org.eclipse.cdt.core.cSource"; //$NON-NLS-1$
 	private static final String CXX_SOURCE = "org.eclipse.cdt.core.cxxSource"; //$NON-NLS-1$
 	private static final String C_HEADER = "org.eclipse.cdt.core.cHeader"; //$NON-NLS-1$
 	private static final String CXX_HEADER = "org.eclipse.cdt.core.cxxHeader"; //$NON-NLS-1$
 	private static final Map<URI, Boolean> cache = Collections.synchronizedMap(new LRUCache<>(100));
-	private static URICache instance = null;
+	private static CLanguageServerEnableCache instance = null;
 
-	private URICache() {
+	private CLanguageServerEnableCache() {
 		ContentTypeManager.getInstance().addContentTypeChangeListener(this);
 		if (PlatformUI.isWorkbenchRunning()) {
 			var workbench = PlatformUI.getWorkbench();
@@ -72,9 +78,9 @@ public static void clear() {
 		cache.clear();
 	}
 
-	public static synchronized URICache getInstance() {
+	public static synchronized CLanguageServerEnableCache getInstance() {
 		if (instance == null) {
-			instance = new URICache();
+			instance = new CLanguageServerEnableCache();
 		}
 		return instance;
 	}
@@ -115,7 +121,7 @@ public void partBroughtToTop(IWorkbenchPart part) {
 
 	@Override
 	public void partClosed(IWorkbenchPart part) {
-		if (part instanceof ExtensionBasedTextEditor editor) {
+		if (part instanceof TextEditor editor) {
 			Optional.ofNullable(LSPEclipseUtils.toUri(editor.getEditorInput())).ifPresent(uri -> cache.remove(uri));
 		}
 	}
@@ -127,7 +133,10 @@ public void partDeactivated(IWorkbenchPart part) {
 
 	@Override
 	public void partOpened(IWorkbenchPart part) {
-		// do nothing
+		if (part instanceof ExtensionBasedTextEditor editor
+				&& LspUtils.isCContentType(LspUtils.getContentType(editor.getEditorInput()))) {
+			Optional.ofNullable(LSPEclipseUtils.toUri(editor.getEditorInput())).ifPresent(uri -> cache.put(uri, true));
+		}
 	}
 
 	@Override

bundles/org.eclipse.cdt.lsp/src/org/eclipse/cdt/lsp/internal/server/CLanguageServerStreamConnectionProvider.java

@@ -89,7 +89,7 @@ public void stop() {
 		super.stop();
 		// then close output stream.
 		getLogProvider().ifPresent(lp -> lp.close());
-		URICache.clear();
+		CLanguageServerEnableCache.clear();
 	}
 
 	private boolean logEnabled() {

bundles/org.eclipse.cdt.lsp/src/org/eclipse/cdt/lsp/internal/server/HasLanguageServerPropertyTester.java

@@ -37,7 +37,7 @@ public class HasLanguageServerPropertyTester extends PropertyTester {
 	private final ICLanguageServerProvider cLanguageServerProvider;
 	private final ServiceCaller<InitialUri> initial;
 	private final ServiceCaller<IWorkspace> workspace;
-	private final URICache cache = URICache.getInstance();
+	private final CLanguageServerEnableCache cache = CLanguageServerEnableCache.getInstance();
 	private Optional<IProject> project;
 
 	public HasLanguageServerPropertyTester() {
@@ -62,7 +62,6 @@ public boolean test(Object receiver, String property, Object[] args, Object expe
 				}
 				// when getProject is empty, it's an external file: Check if the file is already opened, if not check the active editor:
 				var isEnabled = enabledFor(uri);
-				cache.put(uri, isEnabled);
 				if (isEnabled) {
 					initial.call(iu -> iu.register(uri));
 				}

bundles/org.eclipse.cdt.lsp/src/org/eclipse/cdt/lsp/plugin/LspPlugin.java

@@ -17,7 +17,7 @@
 import java.util.logging.Logger;
 
 import org.eclipse.cdt.lsp.internal.server.CLanguageServerRegistry;
-import org.eclipse.cdt.lsp.internal.server.URICache;
+import org.eclipse.cdt.lsp.internal.server.CLanguageServerEnableCache;
 import org.eclipse.cdt.lsp.server.ICLanguageServerProvider;
 import org.eclipse.ui.plugin.AbstractUIPlugin;
 import org.osgi.framework.BundleContext;
@@ -59,7 +59,7 @@ public void start(BundleContext context) throws Exception {
 
 	@Override
 	public void stop(BundleContext context) throws Exception {
-		URICache.stop();
+		CLanguageServerEnableCache.stop();
 		plugin = null;
 		super.stop(context);
 	}

bundles/org.eclipse.cdt.lsp/src/org/eclipse/cdt/lsp/util/LspUtils.java

@@ -21,19 +21,22 @@
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IWorkspace;
+import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.ServiceCaller;
 import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.lsp4e.LanguageServerWrapper;
 import org.eclipse.lsp4e.LanguageServiceAccessor;
 import org.eclipse.ui.IEditorInput;
 import org.eclipse.ui.IEditorReference;
+import org.eclipse.ui.IFileEditorInput;
 import org.eclipse.ui.IURIEditorInput;
 import org.eclipse.ui.PartInitException;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.part.FileEditorInput;
 
 public class LspUtils {
+	private static final String EMPTY = ""; //$NON-NLS-1$
 
 	/**
 	 * Checks if given ContentType id matches the content types for C/C++ files.
@@ -128,6 +131,18 @@ private static boolean isLspEditorActive() {
 		return false;
 	}
 
+	public static String getContentType(IEditorInput editorInput) {
+		if (editorInput instanceof IFileEditorInput fileEditorInput) {
+			try {
+				return Optional.ofNullable(fileEditorInput.getFile().getContentDescription())
+						.map(cd -> cd.getContentType()).map(ct -> ct.getId()).orElse(EMPTY);
+			} catch (CoreException e) {
+				// do nothing
+			}
+		}
+		return EMPTY;
+	}
+
 	//FIXME: AF: consider removing, since it doesn't recognize containers, use UriResource instead
 	public static Optional<IProject> getProject(URI uri) {
 		return getFile(uri).map(file -> file.getProject());