add quote meta func

glob.go

@@ -60,7 +60,7 @@ func MustCompile(pattern string, separators ...rune) Glob {
 func QuoteMeta(s string) string {
 	b := make([]byte, 2*len(s))
 
-	// A byte loop is correct because all metacharacters are ASCII.
+	// a byte loop is correct because all meta characters are ASCII
 	j := 0
 	for i := 0; i < len(s); i++ {
 		if special(s[i]) {

glob_test.go

@@ -151,6 +151,12 @@ func TestGlob(t *testing.T) {
 }
 
 func TestQuoteMeta(t *testing.T) {
+	specialsQuoted := make([]byte, len(specials)*2)
+	for i, j := 0, 0; i < len(specials); i, j = i+1, j+2 {
+		specialsQuoted[j] = '\\'
+		specialsQuoted[j+1] = specials[i]
+	}
+
 	for id, test := range []struct {
 		in, out string
 	}{
@@ -158,11 +164,22 @@ func TestQuoteMeta(t *testing.T) {
 			in:  `[foo*]`,
 			out: `\[foo\*\]`,
 		},
+		{
+			in:  string(specials),
+			out: string(specialsQuoted),
+		},
+		{
+			in:  string(append([]byte("some text and"), specials...)),
+			out: string(append([]byte("some text and"), specialsQuoted...)),
+		},
 	} {
 		act := QuoteMeta(test.in)
 		if act != test.out {
 			t.Errorf("#%d QuoteMeta(%q) = %q; want %q", id, test.in, act, test.out)
 		}
+		if _, err := Compile(act); err != nil {
+			t.Errorf("#%d _, err := Compile(QuoteMeta(%q) = %q); err = %q", id, test.in, act, err)
+		}
 	}
 }