/
composite.go
214 lines (191 loc) · 4.76 KB
/
composite.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
/*
* Copyright (c) 2023 Juice Technologies, Inc. All Rights Reserved.
*/
package postgres
import (
"bytes"
"database/sql"
"errors"
"fmt"
"reflect"
"strconv"
)
var (
errNotPtr = errors.New("destination not a pointer")
errNilPtr = errors.New("destination pointer is nil")
)
type Composite []byte
func (composite Composite) Scan(dest ...any) error {
columns, err := parseComposite(composite)
if err != nil {
return err
}
if len(columns) != len(dest) {
return fmt.Errorf("Composite: expected %d destination arguments in Scan, not %d", len(columns), len(dest))
}
for i, column := range columns {
err := convertColumn(dest[i], column)
if err != nil {
return fmt.Errorf("Composite: Scan error on column index %d, %w", i, err)
}
}
return nil
}
// The following was pulled largely from github.com/lib/pq/array.go:parseArray
func parseComposite(src []byte) ([][]byte, error) {
if len(src) < 1 || src[0] != '(' {
return nil, fmt.Errorf("Composite: unable to parse composite, expected %q at offset %d", '(', 0)
}
i := 1
elems := make([][]byte, 0)
Element:
for i < len(src) {
switch src[i] {
case '"':
elem := []byte{}
escape := false
QuoteSearch:
for i++; i < len(src); i++ {
if escape {
elem = append(elem, src[i])
escape = false
} else {
switch src[i] {
default:
elem = append(elem, src[i])
case '\\':
escape = true
case '"':
i++
// Double double-quotes is an escape
if i < len(src) && src[i] == '"' {
elem = append(elem, src[i])
} else {
elems = append(elems, elem)
break QuoteSearch
}
}
}
}
default:
for start := i; i < len(src); i++ {
if src[i] == ',' || src[i] == ')' {
elem := src[start:i]
if len(elem) == 0 || bytes.Equal(elem, []byte("NULL")) {
elem = nil
}
elems = append(elems, elem)
break
}
}
}
switch src[i] {
case ',':
i++
case ')':
break Element
}
}
if i >= len(src) {
return nil, errors.New("Composite: unable to parse array; unexpected end")
}
if src[i] != ')' {
return nil, fmt.Errorf("Composite: unable to parse array, unexpected %q at offset %d", src[i], i)
}
return elems, nil
}
// The following was pulled largely from database/sql/convert.go:convertAssignRows
func strconvErr(err error) error {
if ne, ok := err.(*strconv.NumError); ok {
return ne.Err
}
return err
}
func convertColumn(dest any, src []byte) error {
if dest == nil {
return errNilPtr
}
switch d := dest.(type) {
case *string:
*d = string(src)
return nil
case *[]byte:
*d = bytes.Clone(src)
return nil
case *bool:
value, err := strconv.ParseBool(string(src))
if err != nil {
return err
}
*d = value
return nil
}
if scanner, ok := dest.(sql.Scanner); ok {
return scanner.Scan(src)
}
dpv := reflect.ValueOf(dest)
if dpv.Kind() != reflect.Pointer {
return errNotPtr
}
if dpv.IsNil() {
return errNilPtr
}
// The following conversions use a string value as an intermediate representation
// to convert between various numeric types.
//
// This also allows scanning into user defined types such as "type Int int64".
// For symmetry, also check for string destination types.
dv := reflect.Indirect(dpv)
switch dv.Kind() {
case reflect.Pointer:
if src == nil {
dv.Set(reflect.Zero(dv.Type()))
return nil
}
dv.Set(reflect.New(dv.Type().Elem()))
return convertColumn(dv.Interface(), src)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if src == nil {
return fmt.Errorf("converting NULL to %s is unsupported", dv.Kind())
}
s := string(src)
i64, err := strconv.ParseInt(s, 10, dv.Type().Bits())
if err != nil {
err = strconvErr(err)
return fmt.Errorf("converting '%q' to a %s: %v", s, dv.Kind(), err)
}
dv.SetInt(i64)
return nil
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if src == nil {
return fmt.Errorf("converting NULL to %s is unsupported", dv.Kind())
}
s := string(src)
u64, err := strconv.ParseUint(s, 10, dv.Type().Bits())
if err != nil {
err = strconvErr(err)
return fmt.Errorf("converting '%q' to a %s: %v", s, dv.Kind(), err)
}
dv.SetUint(u64)
return nil
case reflect.Float32, reflect.Float64:
if src == nil {
return fmt.Errorf("converting NULL to %s is unsupported", dv.Kind())
}
s := string(src)
f64, err := strconv.ParseFloat(s, dv.Type().Bits())
if err != nil {
err = strconvErr(err)
return fmt.Errorf("converting '%q' to a %s: %v", s, dv.Kind(), err)
}
dv.SetFloat(f64)
return nil
case reflect.String:
if src == nil {
return fmt.Errorf("converting NULL to %s is unsupported", dv.Kind())
}
dv.SetString(string(src))
return nil
}
return fmt.Errorf("unsupported Scan, storing %T into type %T", src, dest)
}