[#342] use default editor to open external file (#343)

[#342] use default editor to open external file

...when no other editor is opened to inherit editor type from

Author: ghentschke

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

@@ -49,7 +49,7 @@ public IEditorDescriptor[] overrideEditors(IEditorInput editorInput, IContentTyp
 		if (isNoCElement(contentType)) {
 			return editorDescriptors;
 		}
-		if (isEnabledFor(editorInput)) {
+		if (isEnabledFor(editorInput, contentType)) {
 			return editorFilter(LspPlugin.C_EDITOR_ID, editorDescriptors); // remove CDT C-Editor
 		}
 		return editorFilter(LspPlugin.LSP_C_EDITOR_ID, editorDescriptors); // remove LSP based C-Editor
@@ -82,7 +82,7 @@ public IEditorDescriptor overrideDefaultEditor(String fileName, IContentType con
 		return editorDescriptor;
 	}
 
-	private boolean isEnabledFor(IEditorInput editorInput) {
+	private boolean isEnabledFor(IEditorInput editorInput, IContentType contentType) {
 		if (cLanguageServerProvider == null)
 			return false;
 		IResource resource = editorInput.getAdapter(IResource.class);
@@ -94,7 +94,7 @@ private boolean isEnabledFor(IEditorInput editorInput) {
 			return enabled;
 		}
 		// When resource == null it's an external file: Check if the file is already opened, if not check the active editor:
-		return LspUtils.isFileOpenedInLspEditor(editorInput);
+		return LspUtils.isFileOpenedInLspEditor(editorInput, contentType);
 	}
 
 	private void deleteCodanMarkers(IResource resource) {
@@ -141,7 +141,7 @@ private IEditorDescriptor getEditorDescriptor(IEditorInput editorInput, IContent
 		if (isNoCElement(contentType))
 			return null;
 
-		if (isEnabledFor(editorInput)) {
+		if (isEnabledFor(editorInput, contentType)) {
 			return getEditorDescriptorById(editorInput.getName(), LspPlugin.LSP_C_EDITOR_ID, contentType); // return LSP based C/C++ Editor
 		}
 		// TODO: return null; when either https://github.com/eclipse-cdt/cdt/pull/310 or

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

@@ -24,6 +24,7 @@
 import org.eclipse.core.resources.IWorkspace;
 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;
@@ -79,7 +80,7 @@ public static boolean isFileOpenedInLspEditor(URI uri) {
 		return false;
 	}
 
-	public static boolean isFileOpenedInLspEditor(IEditorInput editorInput) {
+	public static boolean isFileOpenedInLspEditor(IEditorInput editorInput, IContentType contentType) {
 		if (editorInput == null) {
 			return false;
 		}
@@ -100,7 +101,9 @@ public static boolean isFileOpenedInLspEditor(IEditorInput editorInput) {
 			// the file has not been opened yet:
 			return isLspEditorActive();
 		}
-		return false;
+		// check defaults:
+		var desc = PlatformUI.getWorkbench().getEditorRegistry().getDefaultEditor(editorInput.getName(), contentType);
+		return desc != null ? LspPlugin.LSP_C_EDITOR_ID.equals(desc.getId()) : false;
 	}
 
 	public static List<IEditorReference> getEditors() {