Make FileUtils.resolveFile more robust - modelled after File(File, String).

This avoids the explicit checks for null directories in
SourceFileScanner as well.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@269755 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/util/FileUtils.java

@@ -299,7 +299,9 @@ public class FileUtils {
      * @param file the "reference" file for relative paths. This
      * instance must be an absolute file and must not contain
      * "./" or "../" sequences (same for \ instead
-     * of /).
+     * of /).  If it is null, this call is equivalent to
+     * <code>new java.io.File(filename)</code>.
+     *
      * @param filename a file name
      *
      * @return an absolute file that doesn't contain &quot;./&quot; or
@@ -327,6 +329,10 @@ public class FileUtils {
             return normalize(filename);
         }
 
+        if (file == null) {
+            return new File(filename);
+        }
+
         File helpFile = new File(file.getAbsolutePath());
         StringTokenizer tok = new StringTokenizer(filename, File.separator);
         while (tok.hasMoreTokens()) {
@@ -361,6 +367,9 @@ public class FileUtils {
      *   <li>DOS style paths that start with a drive letter will have
      *     \ as the separator.</li> 
      * </ul>
+     *
+     * @throws java.lang.NullPointerException if the file path is
+     * equal to null.
      */
     public File normalize(String path) {
         String orig = path;

src/main/org/apache/tools/ant/util/SourceFileScanner.java

@@ -121,12 +121,7 @@ public class SourceFileScanner {
                 continue;
             }
 
-            File src = null;
-            if (srcDir == null) {
-                src = new File(files[i]);
-            } else {
-                src = fileUtils.resolveFile(srcDir, files[i]);
-            }
+            File src = fileUtils.resolveFile(srcDir, files[i]);
 
             if (src.lastModified() > now) {
                 task.log("Warning: "+files[i]+" modified in the future.", 
@@ -136,12 +131,7 @@ public class SourceFileScanner {
             boolean added = false;
             targetList.setLength(0);
             for (int j=0; !added && j<targets.length; j++) {
-                File dest = null;
-                if (destDir == null) {
-                    dest = new File(targets[j]);
-                } else {
-                    dest = fileUtils.resolveFile(destDir, targets[j]);
-                }
+                File dest = fileUtils.resolveFile(destDir, targets[j]);
                 
                 if (!dest.exists()) {
                     task.log(files[i]+" added as "+dest.getAbsolutePath()+" doesn\'t exist.",

src/testcases/org/apache/tools/ant/util/FileUtilsTest.java

@@ -258,6 +258,21 @@ public class FileUtilsTest extends TestCase {
         }
     }
 
+    /**
+     * Test handling of null arguments.
+     */
+    public void testNullArgs() {
+        try {
+            fu.normalize(null);
+            fail("successfully normalized a null-file");
+        } catch (NullPointerException npe) {
+            // Expected exception caught
+        }
+        
+        File f = fu.resolveFile(null, "a");
+        assertEquals(f, new File("a"));
+    }
+
     /**
      * adapt file separators to local conventions
      */