1 package graphql
2
3 import (
4 "encoding/json"
5 "fmt"
6 "io"
7 "strconv"
8 )
9
10 const encodeHex = "0123456789ABCDEF"
11
12 func MarshalString(s string) Marshaler {
13 return WriterFunc(func(w io.Writer) {
14 writeQuotedString(w, s)
15 })
16 }
17
18 func writeQuotedString(w io.Writer, s string) {
19 start := 0
20 io.WriteString(w, `"`)
21
22 for i, c := range s {
23 if c < 0x20 || c == '\\' || c == '"' {
24 io.WriteString(w, s[start:i])
25
26 switch c {
27 case '\t':
28 io.WriteString(w, `\t`)
29 case '\r':
30 io.WriteString(w, `\r`)
31 case '\n':
32 io.WriteString(w, `\n`)
33 case '\\':
34 io.WriteString(w, `\\`)
35 case '"':
36 io.WriteString(w, `\"`)
37 default:
38 io.WriteString(w, `\u00`)
39 w.Write([]byte{encodeHex[c>>4], encodeHex[c&0xf]})
40 }
41
42 start = i + 1
43 }
44 }
45
46 io.WriteString(w, s[start:])
47 io.WriteString(w, `"`)
48 }
49
50 func UnmarshalString(v interface{}) (string, error) {
51 switch v := v.(type) {
52 case string:
53 return v, nil
54 case int:
55 return strconv.Itoa(v), nil
56 case int64:
57 return strconv.FormatInt(v, 10), nil
58 case float64:
59 return strconv.FormatFloat(v, 'f', -1, 64), nil
60 case json.Number:
61 return string(v), nil
62 case bool:
63 if v {
64 return "true", nil
65 } else {
66 return "false", nil
67 }
68 case nil:
69 return "null", nil
70 default:
71 return "", fmt.Errorf("%T is not a string", v)
72 }
73 }
74
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