Allow leading/trailing spaces in ignore rules

According to [1] leading spaces are allowed in ignore rules and trailing
spaces are allowed too if they are escaped via backslash.

[1] https://www.kernel.org/pub/software/scm/git/docs/gitignore.html

Bug: 472762
Change-Id: I5e3ae5599cb9e5d80072f38c82c20cbc9475a18a
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>

org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/IgnoreNodeTest.java

@@ -374,6 +374,67 @@ public class IgnoreNodeTest extends RepositoryTestCase {
 		endWalk();
 	}
 
+	@Test
+	public void testLeadingSpaces() throws IOException {
+		writeTrashFile("  a/  a", "");
+		writeTrashFile("  a/ a", "");
+		writeTrashFile("  a/a", "");
+		writeTrashFile(" a/  a", "");
+		writeTrashFile(" a/ a", "");
+		writeTrashFile(" a/a", "");
+		writeIgnoreFile(".gitignore", " a", "  a");
+		writeTrashFile("a/  a", "");
+		writeTrashFile("a/ a", "");
+		writeTrashFile("a/a", "");
+
+		beginWalk();
+		assertEntry(D, ignored, "  a");
+		assertEntry(F, ignored, "  a/  a");
+		assertEntry(F, ignored, "  a/ a");
+		assertEntry(F, ignored, "  a/a");
+		assertEntry(D, ignored, " a");
+		assertEntry(F, ignored, " a/  a");
+		assertEntry(F, ignored, " a/ a");
+		assertEntry(F, ignored, " a/a");
+		assertEntry(F, tracked, ".gitignore");
+		assertEntry(D, tracked, "a");
+		assertEntry(F, ignored, "a/  a");
+		assertEntry(F, ignored, "a/ a");
+		assertEntry(F, tracked, "a/a");
+		endWalk();
+	}
+
+	@Test
+	public void testTrailingSpaces() throws IOException {
+		writeTrashFile("a  /a", "");
+		writeTrashFile("a  /a ", "");
+		writeTrashFile("a  /a  ", "");
+		writeTrashFile("a /a", "");
+		writeTrashFile("a /a ", "");
+		writeTrashFile("a /a  ", "");
+		writeTrashFile("a/a", "");
+		writeTrashFile("a/a ", "");
+		writeTrashFile("a/a  ", "");
+
+		writeIgnoreFile(".gitignore", "a\\ ", "a \\ ");
+
+		beginWalk();
+		assertEntry(F, tracked, ".gitignore");
+		assertEntry(D, ignored, "a  ");
+		assertEntry(F, ignored, "a  /a");
+		assertEntry(F, ignored, "a  /a ");
+		assertEntry(F, ignored, "a  /a  ");
+		assertEntry(D, ignored, "a ");
+		assertEntry(F, ignored, "a /a");
+		assertEntry(F, ignored, "a /a ");
+		assertEntry(F, ignored, "a /a  ");
+		assertEntry(D, tracked, "a");
+		assertEntry(F, tracked, "a/a");
+		assertEntry(F, ignored, "a/a ");
+		assertEntry(F, ignored, "a/a  ");
+		endWalk();
+	}
+
 	@Test
 	public void testToString() throws Exception {
 		assertEquals(Arrays.asList("").toString(), new IgnoreNode().toString());

org.eclipse.jgit/src/org/eclipse/jgit/ignore/IgnoreNode.java

@@ -109,9 +109,9 @@ public class IgnoreNode {
 		BufferedReader br = asReader(in);
 		String txt;
 		while ((txt = br.readLine()) != null) {
-			txt = txt.trim();
+			if (txt.length() > 0 && !txt.startsWith("#") && !txt.equals("/")) { //$NON-NLS-1$ //$NON-NLS-2$
-			if (txt.length() > 0 && !txt.startsWith("#") && !txt.equals("/")) //$NON-NLS-1$ //$NON-NLS-2$
 				rules.add(new FastIgnoreRule(txt));
+			}
 		}
 	}