parse: ignore leading whitespace for comments

Comments were only ignored if the string parsed
started with "#". This commit trims leading whitespace
and tab characters to make sure all lines with "#" being the
first non-whitespace character are ignored.

Signed-off-by: Stephen Chung <schung@redhat.com>

check_test.go

@@ -139,3 +139,69 @@ func TestTimeComparison(t *testing.T) {
 		t.Fatal(res.Failures)
 	}
 }
+
+func TestIgnoreComments(t *testing.T) {
+	dir, err := ioutil.TempDir("", "test-comments.")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+
+	// This is the format of time from FreeBSD
+	spec := `
+/set type=file time=5.000000000
+.               type=dir
+    file1       time=5.000000000
+..
+`
+
+	fh, err := os.Create(filepath.Join(dir, "file1"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	// This is what mode we're checking for. Round integer of epoch seconds
+	epoch := time.Unix(5, 0)
+	if err := os.Chtimes(fh.Name(), epoch, epoch); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chtimes(dir, epoch, epoch); err != nil {
+		t.Fatal(err)
+	}
+	if err := fh.Close(); err != nil {
+		t.Error(err)
+	}
+
+	dh, err := ParseSpec(bytes.NewBufferString(spec))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	res, err := Check(dir, dh, nil)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if len(res.Failures) > 0 {
+		t.Fatal(res.Failures)
+	}
+
+	// now change the spec to a comment that looks like an actual Entry but has
+	// whitespace in front of it
+	spec = `
+/set type=file time=5.000000000
+.               type=dir
+    file1       time=5.000000000
+	#file2 		time=5.000000000
+..
+`
+	dh, err = ParseSpec(bytes.NewBufferString(spec))
+
+	res, err = Check(dir, dh, nil)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if len(res.Failures) > 0 {
+		t.Fatal(res.Failures)
+	}
+}

parse.go

@@ -16,11 +16,14 @@ func ParseSpec(r io.Reader) (*DirectoryHierarchy, error) {
 	}
 	for s.Scan() {
 		str := s.Text()
+		trimmedStr := strings.TrimLeftFunc(str, func(c rune) bool {
+			return c == ' ' || c == '\t'
+		})
 		e := Entry{Pos: i}
 		switch {
-		case strings.HasPrefix(str, "#"):
+		case strings.HasPrefix(trimmedStr, "#"):
 			e.Raw = str
-			if strings.HasPrefix(str, "#mtree") {
+			if strings.HasPrefix(trimmedStr, "#mtree") {
 				e.Type = SignatureType
 			} else {
 				e.Type = CommentType