1// Copyright 2014 Google LLC
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// This file provides error functions for common API failure modes.
16
17package datastore
18
19import (
20	"fmt"
21)
22
23// MultiError is returned by batch operations when there are errors with
24// particular elements. Errors will be in a one-to-one correspondence with
25// the input elements; successful elements will have a nil entry.
26type MultiError []error
27
28func (m MultiError) Error() string {
29	s, n := "", 0
30	for _, e := range m {
31		if e != nil {
32			if n == 0 {
33				s = e.Error()
34			}
35			n++
36		}
37	}
38	switch n {
39	case 0:
40		return "(0 errors)"
41	case 1:
42		return s
43	case 2:
44		return s + " (and 1 other error)"
45	}
46	return fmt.Sprintf("%s (and %d other errors)", s, n-1)
47}
48