Add bucket lifecycle expiry feature (#7834)

cmd/utils.go

@@ -475,3 +475,36 @@ func reverseStringSlice(input []string) {
 		input[left], input[right] = input[right], input[left]
 	}
 }
+
+// lcp finds the longest common prefix of the input strings.
+// It compares by bytes instead of runes (Unicode code points).
+// It's up to the caller to do Unicode normalization if desired
+// (e.g. see golang.org/x/text/unicode/norm).
+func lcp(l []string) string {
+	// Special cases first
+	switch len(l) {
+	case 0:
+		return ""
+	case 1:
+		return l[0]
+	}
+	// LCP of min and max (lexigraphically)
+	// is the LCP of the whole set.
+	min, max := l[0], l[0]
+	for _, s := range l[1:] {
+		switch {
+		case s < min:
+			min = s
+		case s > max:
+			max = s
+		}
+	}
+	for i := 0; i < len(min) && i < len(max); i++ {
+		if min[i] != max[i] {
+			return min[:i]
+		}
+	}
+	// In the case where lengths are not equal but all bytes
+	// are equal, min is the answer ("foo" < "foobar").
+	return min
+}