Adding upstream version 0.3.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

levels.go

@@ -0,0 +1,58 @@
+package logr
+
+import (
+	"errors"
+	"strings"
+)
+
+type Level string
+
+const (
+	LevelDebug Level = "DEBUG"
+	LevelInfo  Level = "INFO"
+	LevelWarn  Level = "WARN"
+	LevelError Level = "ERROR"
+	LevelFatal Level = "FATAL"
+)
+
+var (
+	ErrInvalidLevelString = errors.New("invalid level, must be one of DEBUG, INFO, WARN, ERROR or FATAL")
+)
+
+func (level Level) Value() int {
+	switch level {
+	case LevelDebug:
+		return 0
+	case LevelInfo:
+		return 1
+	case LevelWarn:
+		return 2
+	case LevelError:
+		return 3
+	case LevelFatal:
+		return 4
+	default:
+		return -1
+	}
+}
+
+func (level Level) IsValid() bool {
+	return level.Value() != -1
+}
+
+func LevelFromString(level string) (Level, error) {
+	switch strings.ToUpper(level) {
+	case "DEBUG":
+		return LevelDebug, nil
+	case "INFO":
+		return LevelInfo, nil
+	case "WARN":
+		return LevelWarn, nil
+	case "ERROR":
+		return LevelError, nil
+	case "FATAL":
+		return LevelFatal, nil
+	default:
+		return LevelDebug, ErrInvalidLevelString
+	}
+}