PoC - Use Foreign Function & Memory API for GTK3 OS Support

Author: ptziegler

org.eclipse.wb.os.linux/.classpath

@@ -1,7 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-21"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-24">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="src" path="src_java25">
+		<attributes>
+			<attribute name="release" value="25"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

org.eclipse.wb.os.linux/.settings/org.eclipse.jdt.core.prefs

@@ -1,8 +1,8 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
-org.eclipse.jdt.core.compiler.codegen.targetPlatform=21
+org.eclipse.jdt.core.compiler.codegen.targetPlatform=24
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
-org.eclipse.jdt.core.compiler.compliance=21
+org.eclipse.jdt.core.compiler.compliance=24
 org.eclipse.jdt.core.compiler.debug.lineNumber=generate
 org.eclipse.jdt.core.compiler.debug.localVariable=generate
 org.eclipse.jdt.core.compiler.debug.sourceFile=generate
@@ -65,7 +65,7 @@ org.eclipse.jdt.core.compiler.problem.unusedParameterWhenOverridingConcrete=disa
 org.eclipse.jdt.core.compiler.problem.unusedPrivateMember=warning
 org.eclipse.jdt.core.compiler.problem.varargsArgumentNeedCast=warning
 org.eclipse.jdt.core.compiler.release=enabled
-org.eclipse.jdt.core.compiler.source=21
+org.eclipse.jdt.core.compiler.source=24
 org.eclipse.jdt.core.formatter.align_assignment_statements_on_columns=false
 org.eclipse.jdt.core.formatter.align_fields_grouping_blank_lines=2147483647
 org.eclipse.jdt.core.formatter.align_selector_in_method_invocation_on_expression_first_line=true

org.eclipse.wb.os.linux/META-INF/MANIFEST.MF

@@ -4,7 +4,7 @@ Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.wb.os.linux;singleton:=true
 Bundle-Version: 1.10.300.qualifier
 Bundle-Vendor: %providerName
-Bundle-RequiredExecutionEnvironment: JavaSE-21
+Bundle-RequiredExecutionEnvironment: JavaSE-24
 Eclipse-PlatformFilter: (& (osgi.ws=gtk) (osgi.os=linux))
 Require-Bundle: org.eclipse.swt;bundle-version="[3.126.0,4.0.0)",
  org.eclipse.core.runtime;bundle-version="[3.31.100,4.0.0)",
@@ -18,6 +18,7 @@ Bundle-ActivationPolicy: lazy
 Bundle-Localization: plugin
 Import-Package: org.apache.commons.io;version="[2.16.1,3.0.0)",
  org.apache.commons.lang3;version="[3.14.0,4.0.0)",
+ org.apache.commons.lang3.function;version="[3.14.0,4.0.0)",
  org.eclipse.wb.os
 Automatic-Module-Name: org.eclipse.wb.os.linux
 Provide-Capability: wbp;type=os

org.eclipse.wb.os.linux/src/org/eclipse/wb/internal/os/linux/OSSupportLinux.java

@@ -35,6 +35,7 @@
 import org.eclipse.swt.widgets.Menu;
 import org.eclipse.swt.widgets.MenuItem;
 import org.eclipse.swt.widgets.Shell;
+import org.eclipse.swt.widgets.TabItem;
 import org.eclipse.swt.widgets.Tree;
 import org.eclipse.swt.widgets.Widget;
 
@@ -518,7 +519,7 @@ public final int getDefaultMenuBarHeight() {
 	//
 	////////////////////////////////////////////////////////////////////////////
 	@Override
-	public final Rectangle getTabItemBounds(Object tabItem) {
+	public final Rectangle getTabItemBounds(TabItem tabItem) {
 		return getWidgetBounds(tabItem);
 	}
 

org.eclipse.wb.os.linux/src_java25/org/eclipse/wb/internal/os/linux/GdkRectangle.java

@@ -0,0 +1,70 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Patrick Ziegler and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which 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.wb.internal.os.linux;
+
+import java.lang.foreign.Arena;
+import java.lang.foreign.MemoryLayout;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.StructLayout;
+import java.lang.foreign.ValueLayout;
+
+/**
+ * A GdkRectangle data type for representing rectangles.
+ *
+ * GdkRectangle is identical to cairo_rectangle_t. Together with Cairo’s
+ * cairo_region_t data type, these are the central types for representing sets
+ * of pixels.
+ *
+ * The intersection of two rectangles can be computed with
+ * gdk_rectangle_intersect(); to find the union of two rectangles use
+ * gdk_rectangle_union().
+ *
+ * The cairo_region_t type provided by Cairo is usually used for managing
+ * non-rectangular clipping of graphical operations.
+ *
+ * The Graphene library has a number of other data types for regions and volumes
+ * in 2D and 3D.
+ */
+public sealed class GdkRectangle permits GtkAllocation {
+	private static final StructLayout LAYOUT = MemoryLayout.structLayout( //
+			ValueLayout.JAVA_INT.withName("x"), //
+			ValueLayout.JAVA_INT.withName("y"), //
+			ValueLayout.JAVA_INT.withName("width"), //
+			ValueLayout.JAVA_INT.withName("height"));
+
+	private final MemorySegment segment;
+
+	public GdkRectangle(Arena arena) {
+		segment = arena.allocate(LAYOUT);
+	}
+
+	public final int x() {
+		return segment.get(ValueLayout.JAVA_INT, 0);
+	}
+
+	public final int y() {
+		return segment.get(ValueLayout.JAVA_INT, 4);
+	}
+
+	public final int width() {
+		return segment.get(ValueLayout.JAVA_INT, 8);
+	}
+
+	public final int height() {
+		return segment.get(ValueLayout.JAVA_INT, 12);
+	}
+
+	public final MemorySegment segment() {
+		return segment;
+	}
+}

org.eclipse.wb.os.linux/src_java25/org/eclipse/wb/internal/os/linux/GtkAllocation.java

@@ -0,0 +1,25 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Patrick Ziegler and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which 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.wb.internal.os.linux;
+
+import java.lang.foreign.Arena;
+
+/**
+ * A GtkAllocation-struct of a widget represents region which has been allocated
+ * to the widget by its parent. It is a subregion of its parents allocation.
+ */
+public final class GtkAllocation extends GdkRectangle {
+	public GtkAllocation(Arena arena) {
+		super(arena);
+	}
+}

org.eclipse.wb.os.linux/src_java25/org/eclipse/wb/internal/os/linux/GtkRuntimeException.java

@@ -0,0 +1,26 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Patrick Ziegler and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which 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.wb.internal.os.linux;
+
+import org.eclipse.wb.os.OSRuntimeException;
+
+/**
+ * Wrapper for all exceptions thrown while accessing native code.
+ */
+public class GtkRuntimeException extends OSRuntimeException {
+	private static final long serialVersionUID = 1L;
+
+	public GtkRuntimeException(Throwable t) {
+		super(t);
+	}
+}

org.eclipse.wb.os.linux/src_java25/org/eclipse/wb/internal/os/linux/GtkWidget.java

@@ -0,0 +1,64 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Patrick Ziegler and others.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which 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.wb.internal.os.linux;
+
+import org.eclipse.wb.internal.core.utils.reflect.ReflectionUtils;
+
+import org.eclipse.swt.widgets.Shell;
+import org.eclipse.swt.widgets.Widget;
+
+/**
+ * GtkWidget is the base class all widgets in GTK+ derive from. It manages the
+ * widget lifecycle, states and style.
+ */
+public record GtkWidget(long handle) {
+
+	public GtkWidget(Shell shell) {
+		this(getShellHandle(shell));
+	}
+
+	public GtkWidget(Widget widget) {
+		this(getHandle(widget));
+	}
+
+	/**
+	 * @return the handle value of the {@link Shell} using reflection.
+	 */
+	private static long getShellHandle(Shell shell) {
+		long widgetHandle = getHandleValue(shell, "fixedHandle");
+		if (widgetHandle == 0) {
+			// may be null, roll back to "shellHandle"
+			widgetHandle = getHandleValue(shell, "shellHandle");
+		}
+		return widgetHandle;
+	}
+
+	/**
+	 * @return the handle value of the {@link Widget} using reflection.
+	 */
+	private static long getHandle(Widget widget) {
+		return getHandleValue(widget, "handle");
+	}
+
+	/**
+	 * @return the widget as native pointer for native handles. Note: returns 0 if
+	 *         handle cannot be obtained.
+	 */
+	private static long getHandleValue(Object widget, String fieldName) {
+		if (ReflectionUtils.getFieldObject(widget, fieldName) instanceof Long longValue) {
+			return longValue;
+		}
+		// field might be shadowed (e.g. in ImageBasedFrame)
+		return 0L;
+	}
+}