Extract FileUtils updates by @ericvergnaud in antlr#4027 then he can …

…rebase after we merge this into dev. All tests pass locally (didn't check python2 actually but python3 works).

Signed-off-by: Terence Parr <[email protected]>

runtime-testsuite/test/org/antlr/v4/test/runtime/FileUtils.java

@@ -8,9 +8,15 @@
 
 import org.antlr.v4.runtime.misc.Utils;
 
-import java.io.*;
+import java.io.File;
+import java.io.IOException;
+import java.io.PrintWriter;
 import java.nio.charset.StandardCharsets;
-import java.nio.file.*;
+import java.nio.file.Files;
+import java.nio.file.LinkOption;
+import java.nio.file.Path;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.nio.file.attribute.DosFileAttributes;
 
 import static org.antlr.v4.test.runtime.RuntimeTestUtils.FileSeparator;
 
@@ -55,7 +61,7 @@ public static void mkdir(String dir) {
 	}
 
 	public static void deleteDirectory(File f) throws IOException {
-		if (f.isDirectory()) {
+		if (f.isDirectory() && !isLink(f.toPath())) {
 			File[] files = f.listFiles();
 			if (files != null) {
 				for (File c : files)
@@ -65,4 +71,13 @@ public static void deleteDirectory(File f) throws IOException {
 		if (!f.delete())
 			throw new IOException("Failed to delete file: " + f);
 	}
+
+	public static boolean isLink(Path path) throws IOException {
+		try {
+			BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
+			return attrs.isSymbolicLink() || (attrs instanceof DosFileAttributes && attrs.isOther());
+		} catch (IOException ignored) {
+			return false;
+		}
+	}
 }