[GTK4] Cleanup execution of non-blocking dialog calls

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/internal/AsyncReadyCallback.java

@@ -0,0 +1,38 @@
+/*******************************************************************************
+ * Copyright (c) 2024 Patrick Ziegler 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:
+ *     Patrick Ziegler - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.internal;
+
+/**
+ * This class implements the GIO AsyncReadyCallback type and is used to
+ * transform an asynchronous {@code async} and synchronous {@code await}
+ * operation into a single synchronous {@code run} operation.
+ */
+public interface AsyncReadyCallback {
+	/**
+	 * This method is responsible for initializes the asynchronous operation
+	 *
+	 * @param callback The callback address to execute when the operation is
+	 *                 complete.
+	 */
+	void async(long callback);
+
+	/**
+	 * This method is called from within the callback function in order to
+	 * finish the executed operation and to return the result.
+	 *
+	 * @param result The generic, asynchronous function result.
+	 * @return The specific result of the operation.
+	 */
+	long await(long result);
+}

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/internal/SyncDialogUtil.java

@@ -48,11 +48,11 @@ public class SyncDialogUtil {
 	 * therefore essential that callers use the address of the {@link Callback}
 	 * as address for the {@code AsyncReadyCallback} object.
 	 */
-	static public long run(Display display, Consumer<Long> asyncOpen, Function<Long, Long> asyncFinish) {
+	static public long run(Display display, AsyncReadyCallback callback) {
 		initializeResponseCallback();
 
-		dialogAsyncFinish = asyncFinish;
-		asyncOpen.accept(dialogResponseCallback.getAddress());
+		dialogAsyncFinish = callback::await;
+		callback.async(dialogResponseCallback.getAddress());
 
 		while (!display.isDisposed()) {
 			if (dialogAsyncValue != null) {

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/DirectoryDialog.java

@@ -214,9 +214,17 @@ Optional<String> openNativeChooserDialog () {
 	int response;
 	long file = 0;
 	if (GTK.GTK4) {
-		file = SyncDialogUtil.run(display,
-				asyncCallback -> GTK4.gtk_file_dialog_select_folder(handle, shellHandle, 0, asyncCallback, 0),
-				asyncResult -> GTK4.gtk_file_dialog_select_folder_finish(handle, asyncResult, null));
+		file = SyncDialogUtil.run(display, new AsyncReadyCallback() {
+			@Override
+			public void async(long result) {
+				GTK4.gtk_file_dialog_select_folder(handle, shellHandle, 0, result, 0);
+			}
+
+			@Override
+			public long await(long result) {
+				return GTK4.gtk_file_dialog_select_folder_finish(handle, result, null);
+			}
+		});
 		response = file != 0 ? GTK.GTK_RESPONSE_ACCEPT : GTK.GTK_RESPONSE_CANCEL;
 	} else {
 		display.externalEventLoop = true;

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/FileDialog.java

@@ -404,18 +404,42 @@ Optional<String> openNativeChooserDialog () {
 	long file = 0;
 	if (GTK.GTK4) {
 		if ((style & SWT.MULTI) != 0) {
-			file = SyncDialogUtil.run(display,
-					asyncCallback -> GTK4.gtk_file_dialog_open_multiple(handle, shellHandle, 0, asyncCallback, 0),
-					asyncResult -> GTK4.gtk_file_dialog_open_multiple_finish(handle, asyncResult, null));
+			file = SyncDialogUtil.run(display, new AsyncReadyCallback() {
+				@Override
+				public void async(long callback) {
+					GTK4.gtk_file_dialog_open_multiple(handle, shellHandle, 0, callback, 0);
+				}
+
+				@Override
+				public long await(long result) {
+					return GTK4.gtk_file_dialog_open_multiple_finish(handle, result, null);
+				}
+			});
 		} else {
 			if ((style & SWT.SAVE) != 0) {
-				file = SyncDialogUtil.run(display,
-						asyncCallback -> GTK4.gtk_file_dialog_save(handle, shellHandle, 0, asyncCallback, 0),
-						asyncResult -> GTK4.gtk_file_dialog_save_finish(handle, asyncResult, null));
+				file = SyncDialogUtil.run(display, new AsyncReadyCallback() {
+					@Override
+					public void async(long callback) {
+						GTK4.gtk_file_dialog_save(handle, shellHandle, 0, callback, 0);
+					}
+
+					@Override
+					public long await(long result) {
+						return GTK4.gtk_file_dialog_save_finish(handle, result, null);
+					}
+				});
 			} else {
-				file = SyncDialogUtil.run(display,
-						asyncCallback -> GTK4.gtk_file_dialog_open(handle, shellHandle, 0, asyncCallback, 0),
-						asyncResult -> GTK4.gtk_file_dialog_open_finish(handle, asyncResult, null));
+				file = SyncDialogUtil.run(display, new AsyncReadyCallback() {
+					@Override
+					public void async(long callback) {
+						GTK4.gtk_file_dialog_open(handle, shellHandle, 0, callback, 0);
+					}
+
+					@Override
+					public long await(long result) {
+						return GTK4.gtk_file_dialog_open_finish(handle, result, null);
+					}
+				});
 			}
 		}
 		response = file != 0 ? GTK.GTK_RESPONSE_ACCEPT : GTK.GTK_RESPONSE_CANCEL;