[IO-727] FilenameUtils directoryContains() should handle files with the

same prefix #217.

Apply a modified PR #217 from trungPa to resolve conflicts.

Author: Gary Gregory

src/changes/changes.xml

@@ -59,6 +59,9 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="fix" due-to="Davide Angelocola">
         Fix usage of assertNotNull #269.
       </action>
+      <action issue="IO-727" dev="ggregory" type="fix" due-to="trungPa, Gary Gregory">
+        FilenameUtils directoryContains() should handle files with the same prefix #217.
+      </action>
       <!-- ADD -->
       <action dev="ggregory" type="add" due-to="Gary Gregory">
         Add BrokenReader.INSTANCE.

src/main/java/org/apache/commons/io/FilenameUtils.java

@@ -23,7 +23,6 @@
 import java.util.Collection;
 import java.util.Deque;
 import java.util.List;
-import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -539,17 +538,22 @@ public static String concat(final String basePath, final String fullFileNameToAd
      * @see FileUtils#directoryContains(File, File)
      */
     public static boolean directoryContains(final String canonicalParent, final String canonicalChild) {
-        Objects.requireNonNull(canonicalParent, "canonicalParent");
-
-        if (canonicalChild == null) {
+        if (isEmpty(canonicalParent) || isEmpty(canonicalChild)) {
             return false;
         }
 
         if (IOCase.SYSTEM.checkEquals(canonicalParent, canonicalChild)) {
             return false;
         }
 
-        return IOCase.SYSTEM.checkStartsWith(canonicalChild, canonicalParent);
+        final char separator = canonicalParent.charAt(0) == UNIX_SEPARATOR ? UNIX_SEPARATOR : WINDOWS_SEPARATOR;
+        final String parentWithEndSeparator = canonicalParent.charAt(canonicalParent.length() - 1) == separator ? canonicalParent : canonicalParent + separator;
+
+        return IOCase.SYSTEM.checkStartsWith(canonicalChild, parentWithEndSeparator);
+    }
+
+    private static boolean isEmpty(final String string) {
+        return string == null || string.isEmpty();
     }
 
     /**
@@ -1235,7 +1239,7 @@ public static boolean isExtension(final String fileName, final String extension)
         }
         requireNonNullChars(fileName);
 
-        if (extension == null || extension.isEmpty()) {
+        if (isEmpty(extension)) {
             return indexOfExtension(fileName) == NOT_FOUND;
         }
         final String fileExt = getExtension(fileName);

src/test/java/org/apache/commons/io/FileUtilsDirectoryContainsTestCase.java

@@ -139,6 +139,19 @@ public void testIO466() throws IOException {
             assertFalse(FileUtils.directoryContains(directory1, fooFile));
     }
 
+    @Test
+    public void testFileHavingSamePrefixBug() throws IOException {
+        final File foo = new File(top, "foo");
+        final File foobar = new File(top, "foobar");
+        final File fooTxt = new File(top, "foo.txt");
+        foo.mkdir();
+        foobar.mkdir();
+        FileUtils.touch(fooTxt);
+
+        assertFalse(FileUtils.directoryContains(foo, foobar));
+        assertFalse(FileUtils.directoryContains(foo, fooTxt));
+    }
+
     @Test
     public void testFileDoesNotExist() throws IOException {
         assertFalse(FileUtils.directoryContains(top, null));

src/test/java/org/apache/commons/io/FilenameUtilsTestCase.java

@@ -1184,4 +1184,21 @@ public void testIsExtensionCollection() {
         assertFalse(FilenameUtils.isExtension("a.b\\file.txt", new ArrayList<>(Arrays.asList("TXT"))));
         assertFalse(FilenameUtils.isExtension("a.b\\file.txt", new ArrayList<>(Arrays.asList("TXT", "RTF"))));
     }
+
+    //-----------------------------------------------------------------------
+    @Test
+    public void testDirectoryContains() throws IOException {
+        assertTrue(FilenameUtils.directoryContains("/foo", "/foo/bar"));
+        assertTrue(FilenameUtils.directoryContains("/foo/", "/foo/bar"));
+        assertTrue(FilenameUtils.directoryContains("C:\\foo", "C:\\foo\\bar"));
+        assertTrue(FilenameUtils.directoryContains("C:\\foo\\", "C:\\foo\\bar"));
+
+        assertFalse(FilenameUtils.directoryContains("/foo", "/foo"));
+        assertFalse(FilenameUtils.directoryContains("/foo", "/foobar"));
+        assertFalse(FilenameUtils.directoryContains("C:\\foo", "C:\\foobar"));
+        assertFalse(FilenameUtils.directoryContains("/foo", null));
+        assertFalse(FilenameUtils.directoryContains("", ""));
+        assertFalse(FilenameUtils.directoryContains("", "/foo"));
+        assertFalse(FilenameUtils.directoryContains("/foo", ""));
+    }
 }