Restore correct URL/URI handling in URLImageDescriptor

The changes done with cee4631 cause an
exception when URL is passed as an argument which contains improperly
escaped characters (most noticeably whitespaces) and therefore causes an
URISyntaxException when calling URL.toURI().

This does not occur when using IPath.fromOSString(), which is the
approach that was done previously. But instead of converting this path
back to an OS-dependent string, it is instead converted to a file, to
check whether it exists and to only then convert it back to its String
representation.

A test case with an ill-formed URL has been added to avoid a similar
problem in the future.

Author: pzi

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

@@ -19,19 +19,18 @@
 
 
 import java.io.BufferedInputStream;
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.MalformedURLException;
-import java.net.URISyntaxException;
 import java.net.URL;
-import java.nio.file.Files;
-import java.nio.file.Path;
 import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import org.eclipse.core.runtime.FileLocator;
 import org.eclipse.core.runtime.IAdaptable;
+import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.internal.InternalPolicy;
 import org.eclipse.jface.util.Policy;
@@ -254,7 +253,7 @@ private static String getFilePath(URL url, boolean logException) {
 			url = resolvePathVariables(url);
 			URL locatedURL = FileLocator.toFileURL(url);
 			return getFilePath(locatedURL);
-		} catch (IOException | URISyntaxException e) {
+		} catch (IOException e) {
 			if (logException) {
 				Policy.logException(e);
 			} else if (InternalPolicy.DEBUG_LOG_URL_IMAGE_DESCRIPTOR_MISSING_2x) {
@@ -267,11 +266,11 @@ private static String getFilePath(URL url, boolean logException) {
 		}
 	}
 
-	private static String getFilePath(URL url) throws URISyntaxException {
+	private static String getFilePath(URL url) {
 		if (FILE_PROTOCOL.equalsIgnoreCase(url.getProtocol())) {
-			Path filePath = Path.of(url.toURI());
-			if (Files.exists(filePath)) {
-				return filePath.toString();
+			File file = IPath.fromOSString(url.getPath()).toFile();
+			if (file.exists()) {
+				return file.getPath();
 			}
 		}
 		return null;

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

@@ -21,6 +21,7 @@
 import static org.junit.Assert.assertNotSame;
 import static org.junit.Assert.assertNull;
 
+import java.io.File;
 import java.io.IOException;
 import java.net.URL;
 
@@ -154,6 +155,24 @@ private void testImageFileNameProviderGetxName_forFileURL(boolean osgiAvailable)
 		}
 	}
 
+	@Test
+	public void testImageFileNameProviderGetxName_forFileURL_WhiteSpace() throws IOException {
+		File imageFolder = tempFolder.newFolder("folder with spaces");
+		File imageFile = new File(imageFolder, "image with spaces.png");
+		imageFile.createNewFile();
+
+		// This is an invalid URL because the whitespace characters are not properly
+		// encoded
+		URL imageFileURL = new URL("file", null, imageFile.getPath());
+		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);
+	}
+
 	@Test
 	public void testAdaptToURL() {
 		ImageDescriptor descriptor = ImageDescriptor