added ErrorString and MultiError

errors/multierror.go

@@ -0,0 +1,56 @@
+package errors
+
+import (
+	"bytes"
+	"fmt"
+)
+
+type ErrorString string
+
+func (es ErrorString) Error() string {
+	return string(es)
+}
+
+type MultiError struct {
+	Errors []error
+}
+
+func (me *MultiError) Append(err interface{}) (added bool) {
+	added = true
+	switch err := err.(type) {
+	case error:
+		me.Errors = append(me.Errors, err)
+	case string:
+		me.Errors = append(me.Errors, ErrorString(err))
+	case []byte:
+		me.Errors = append(me.Errors, ErrorString(err))
+	case *MultiError:
+		me.Errors = append(me.Errors, err.Errors...)
+	case MultiError:
+		me.Errors = append(me.Errors, err.Errors...)
+	case []error:
+		me.Errors = append(me.Errors, err...)
+	case nil:
+		added = false
+	default:
+		added = false
+	}
+	return
+}
+
+func (me *MultiError) Len() int {
+	return len(me.Errors)
+}
+
+func (me *MultiError) Error() string {
+	if len(me.Errors) == 1 {
+		return me.Errors[0].Error()
+	}
+
+	buf := &bytes.Buffer{}
+	buf.WriteString("Multiple Errors Found:\n")
+	for i, e := range me.Errors {
+		fmt.Fprintf(buf, "\t[%d] %s\n", i, e.Error())
+	}
+	return buf.String()[:buf.Len()-1] // skip the last \n
+}