1// Copyright 2009 The Go Authors. All rights reserved.
2// Copyright 2019 Dominik Honnef. All rights reserved.
3
4package staticcheck
5
6import "strconv"
7
8func parseStructTag(tag string) (map[string][]string, error) {
9	// FIXME(dh): detect missing closing quote
10	out := map[string][]string{}
11
12	for tag != "" {
13		// Skip leading space.
14		i := 0
15		for i < len(tag) && tag[i] == ' ' {
16			i++
17		}
18		tag = tag[i:]
19		if tag == "" {
20			break
21		}
22
23		// Scan to colon. A space, a quote or a control character is a syntax error.
24		// Strictly speaking, control chars include the range [0x7f, 0x9f], not just
25		// [0x00, 0x1f], but in practice, we ignore the multi-byte control characters
26		// as it is simpler to inspect the tag's bytes than the tag's runes.
27		i = 0
28		for i < len(tag) && tag[i] > ' ' && tag[i] != ':' && tag[i] != '"' && tag[i] != 0x7f {
29			i++
30		}
31		if i == 0 || i+1 >= len(tag) || tag[i] != ':' || tag[i+1] != '"' {
32			break
33		}
34		name := string(tag[:i])
35		tag = tag[i+1:]
36
37		// Scan quoted string to find value.
38		i = 1
39		for i < len(tag) && tag[i] != '"' {
40			if tag[i] == '\\' {
41				i++
42			}
43			i++
44		}
45		if i >= len(tag) {
46			break
47		}
48		qvalue := string(tag[:i+1])
49		tag = tag[i+1:]
50
51		value, err := strconv.Unquote(qvalue)
52		if err != nil {
53			return nil, err
54		}
55		out[name] = append(out[name], value)
56	}
57	return out, nil
58}
59