forked from klauspost/json
/
indent.go
232 lines (212 loc) · 5.11 KB
/
indent.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package json
import (
"bufio"
"bytes"
"io"
)
// Compact appends to dst the JSON-encoded src with
// insignificant space characters elided.
func Compact(dst *bytes.Buffer, src []byte) error {
return compact(dst, src, false)
}
func compact(dst *bytes.Buffer, src []byte, escape bool) error {
origLen := dst.Len()
var scan scanner
scan.reset()
start := 0
for i, c := range src {
if escape && (c == '<' || c == '>' || c == '&') {
if start < i {
dst.Write(src[start:i])
}
dst.WriteString(`\u00`)
dst.WriteByte(hex[c>>4])
dst.WriteByte(hex[c&0xF])
start = i + 1
}
// Convert U+2028 and U+2029 (E2 80 A8 and E2 80 A9).
if c == 0xE2 && i+2 < len(src) && src[i+1] == 0x80 && src[i+2]&^1 == 0xA8 {
if start < i {
dst.Write(src[start:i])
}
dst.WriteString(`\u202`)
dst.WriteByte(hex[src[i+2]&0xF])
start = i + 3
}
v := scan.step(&scan, int(c))
if v >= scanSkipSpace {
if v == scanError {
break
}
if start < i {
dst.Write(src[start:i])
}
start = i + 1
}
}
if scan.eof() == scanError {
dst.Truncate(origLen)
return scan.err
}
if start < len(src) {
dst.Write(src[start:])
}
return nil
}
func newline(dst *bytes.Buffer, prefix, indent string, depth int) {
dst.WriteByte('\n')
dst.WriteString(prefix)
for i := 0; i < depth; i++ {
dst.WriteString(indent)
}
}
// Indent appends to dst an indented form of the JSON-encoded src.
// Each element in a JSON object or array begins on a new,
// indented line beginning with prefix followed by one or more
// copies of indent according to the indentation nesting.
// The data appended to dst does not begin with the prefix nor
// any indentation, and has no trailing newline, to make it
// easier to embed inside other formatted JSON data.
func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) error {
origLen := dst.Len()
var scan scanner
scan.reset()
needIndent := false
depth := 0
for _, c := range src {
scan.bytes++
v := scan.step(&scan, int(c))
if v == scanSkipSpace {
continue
}
if v == scanError {
break
}
if needIndent && v != scanEndObject && v != scanEndArray {
needIndent = false
depth++
newline(dst, prefix, indent, depth)
}
// Emit semantically uninteresting bytes
// (in particular, punctuation in strings) unmodified.
if v == scanContinue {
dst.WriteByte(c)
continue
}
// Add spacing around real punctuation.
switch c {
case '{', '[':
// delay indent so that empty object and array are formatted as {} and [].
needIndent = true
dst.WriteByte(c)
case ',':
dst.WriteByte(c)
newline(dst, prefix, indent, depth)
case ':':
dst.WriteByte(c)
dst.WriteByte(' ')
case '}', ']':
if needIndent {
// suppress indent in empty object/array
needIndent = false
} else {
depth--
newline(dst, prefix, indent, depth)
}
dst.WriteByte(c)
default:
dst.WriteByte(c)
}
}
if scan.eof() == scanError {
dst.Truncate(origLen)
return scan.err
}
return nil
}
func newlineStream(dst *bufio.Writer, prefix, indent string, depth int) {
dst.WriteByte('\n')
dst.WriteString(prefix)
for i := 0; i < depth; i++ {
dst.WriteString(indent)
}
}
// IndentStream appends to dst an indented form of the JSON-encoded src.
// Each element in a JSON object or array begins on a new,
// indented line beginning with prefix followed by one or more
// copies of indent according to the indentation nesting.
// The data appended to dst does not begin with the prefix nor
// any indentation, and has no trailing newline, to make it
// easier to embed inside other formatted JSON data.
func IndentStream(d io.Writer, src io.Reader, prefix, indent string) error {
dst := bufio.NewWriter(d)
defer dst.Flush()
var scan scanner
scan.reset()
needIndent := false
depth := 0
buf := make([]byte, 1)
for {
n, err := src.Read(buf)
if err != nil && err != io.EOF {
return err
}
if err != nil {
return nil
}
if n == 0 {
continue
}
c := buf[0]
scan.bytes++
v := scan.step(&scan, int(c))
if v == scanSkipSpace {
continue
}
if v == scanError {
break
}
if needIndent && v != scanEndObject && v != scanEndArray {
needIndent = false
depth++
newlineStream(dst, prefix, indent, depth)
}
// Emit semantically uninteresting bytes
// (in particular, punctuation in strings) unmodified.
if v == scanContinue {
dst.WriteByte(c)
continue
}
// Add spacing around real punctuation.
switch c {
case '{', '[':
// delay indent so that empty object and array are formatted as {} and [].
needIndent = true
dst.WriteByte(c)
case ',':
dst.WriteByte(c)
newlineStream(dst, prefix, indent, depth)
case ':':
dst.WriteByte(c)
dst.WriteByte(' ')
case '}', ']':
if needIndent {
// suppress indent in empty object/array
needIndent = false
} else {
depth--
newlineStream(dst, prefix, indent, depth)
}
dst.WriteByte(c)
default:
dst.WriteByte(c)
}
}
if scan.eof() == scanError {
return scan.err
}
return nil
}