Extend existence check in URLImageDescriptor when running without OSGi

This extends the check added in cff785d
to also consider the case when OSGi isn't running. Otherwise a path to a
non-existent file is returned, thus breaking the contract specified in
the JavaDoc.

Author: ptziegler

bundles/org.eclipse.jface/META-INF/MANIFEST.MF

@@ -18,7 +18,7 @@ Export-Package: org.eclipse.jface,
  org.eclipse.jface.fieldassist,
  org.eclipse.jface.fieldassist.images,
  org.eclipse.jface.images,
- org.eclipse.jface.internal;x-friends:="org.eclipse.ui.workbench,org.eclipse.e4.ui.workbench.renderers.swt",
+ org.eclipse.jface.internal;x-friends:="org.eclipse.ui.workbench,org.eclipse.e4.ui.workbench.renderers.swt,org.eclipse.jface.tests",
  org.eclipse.jface.internal.provisional.action;x-friends:="org.eclipse.ui.workbench,org.eclipse.ui.ide",
  org.eclipse.jface.layout,
  org.eclipse.jface.menus,

bundles/org.eclipse.jface/src/org/eclipse/jface/resource/URLImageDescriptor.java

@@ -249,8 +249,12 @@ private static String getxPath(String name, int zoom) {
 	private static String getFilePath(URL url, boolean logIOException) {
 		try {
 			if (!InternalPolicy.OSGI_AVAILABLE) {
-				if (FILE_PROTOCOL.equalsIgnoreCase(url.getProtocol()))
-					return IPath.fromOSString(url.getFile()).toOSString();
+				if (FILE_PROTOCOL.equalsIgnoreCase(url.getProtocol())) {
+					String filePath = IPath.fromOSString(url.getFile()).toOSString();
+					if (Files.exists(Path.of(filePath))) {
+						return filePath;
+					}
+				}
 				return null;
 			}
 			url = resolvePathVariables(url);

tests/org.eclipse.jface.tests/src/org/eclipse/jface/tests/images/UrlImageDescriptorTest.java

@@ -26,6 +26,7 @@
 
 import org.eclipse.core.runtime.Adapters;
 import org.eclipse.core.runtime.IPath;
+import org.eclipse.jface.internal.InternalPolicy;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.ImageData;
@@ -122,20 +123,35 @@ public void testImageFileNameProviderGetxName() {
 
 	@Test
 	public void testImageFileNameProviderGetxName_forFileURL() throws IOException {
-		URL imageFileURL = tempFolder.newFile("image.png").toURI().toURL();
-		tempFolder.newFile("[email protected]");
-		ImageDescriptor descriptor = ImageDescriptor.createFromURL(imageFileURL);
+		testImageFileNameProviderGetxName_forFileURL(true);
+	}
 
-		ImageFileNameProvider fileNameProvider = Adapters.adapt(descriptor, ImageFileNameProvider.class);
-		assertNotNull("URLImageDescriptor does not adapt to ImageFileNameProvider", fileNameProvider);
-		String imagePath100 = fileNameProvider.getImagePath(100);
-		assertNotNull("URLImageDescriptor ImageFileNameProvider does not return the 100% path", imagePath100);
-		assertEquals(IPath.fromOSString(imagePath100).lastSegment(), "image.png");
-		String imagePath200 = fileNameProvider.getImagePath(200);
-		assertNotNull("URLImageDescriptor ImageFileNameProvider does not return the @2x path", imagePath200);
-		assertEquals(IPath.fromOSString(imagePath200).lastSegment(), "[email protected]");
-		String imagePath150 = fileNameProvider.getImagePath(150);
-		assertNull("URLImageDescriptor's ImageFileNameProvider does return a @1.5x path", imagePath150);
+	@Test
+	public void testImageFileNameProviderGetxName_forFileURL_noOSGi() throws IOException {
+		testImageFileNameProviderGetxName_forFileURL(false);
+	}
+
+	private void testImageFileNameProviderGetxName_forFileURL(boolean osgiAvailable) throws IOException {
+		boolean oldOsgiAvailable = InternalPolicy.OSGI_AVAILABLE;
+		InternalPolicy.OSGI_AVAILABLE = osgiAvailable;
+		try {
+			URL imageFileURL = tempFolder.newFile("image.png").toURI().toURL();
+			tempFolder.newFile("[email protected]");
+			ImageDescriptor descriptor = ImageDescriptor.createFromURL(imageFileURL);
+
+			ImageFileNameProvider fileNameProvider = Adapters.adapt(descriptor, ImageFileNameProvider.class);
+			assertNotNull("URLImageDescriptor does not adapt to ImageFileNameProvider", fileNameProvider);
+			String imagePath100 = fileNameProvider.getImagePath(100);
+			assertNotNull("URLImageDescriptor ImageFileNameProvider does not return the 100% path", imagePath100);
+			assertEquals(IPath.fromOSString(imagePath100).lastSegment(), "image.png");
+			String imagePath200 = fileNameProvider.getImagePath(200);
+			assertNotNull("URLImageDescriptor ImageFileNameProvider does not return the @2x path", imagePath200);
+			assertEquals(IPath.fromOSString(imagePath200).lastSegment(), "[email protected]");
+			String imagePath150 = fileNameProvider.getImagePath(150);
+			assertNull("URLImageDescriptor's ImageFileNameProvider does return a @1.5x path", imagePath150);
+		} finally {
+			InternalPolicy.OSGI_AVAILABLE = oldOsgiAvailable;
+		}
 	}
 
 	@Test