forked from minus5/gofreetds
-
Notifications
You must be signed in to change notification settings - Fork 0
/
convert.go
248 lines (231 loc) · 5.64 KB
/
convert.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
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
// This is code from http://golang.org/src/pkg/database/sql/convert.go
// Copyright 2011 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 freetds
import (
"database/sql"
"database/sql/driver"
"errors"
"fmt"
"reflect"
"strconv"
"time"
)
var errNilPtr = errors.New("destination pointer is nil") // embedded in descriptive error
// RawBytes is a byte slice that holds a reference to memory owned by
// the database itself. After a Scan into a RawBytes, the slice is only
// valid until the next call to Next, Scan, or Close.
type RawBytes []byte
// convertAssign copies to dest the value in src, converting it if possible.
// An error is returned if the copy would result in loss of information.
// dest should be a pointer type.
func convertAssign(dest, src interface{}) error {
// Common cases, without reflect.
switch s := src.(type) {
case string:
switch d := dest.(type) {
case *string:
if d == nil {
return errNilPtr
}
*d = s
return nil
case *[]byte:
if d == nil {
return errNilPtr
}
*d = []byte(s)
return nil
}
case []byte:
switch d := dest.(type) {
case *string:
if d == nil {
return errNilPtr
}
*d = string(s)
return nil
case *interface{}:
if d == nil {
return errNilPtr
}
*d = cloneBytes(s)
return nil
case *[]byte:
if d == nil {
return errNilPtr
}
*d = cloneBytes(s)
return nil
case *RawBytes:
if d == nil {
return errNilPtr
}
*d = s
return nil
}
case nil:
switch d := dest.(type) {
case *interface{}:
if d == nil {
return errNilPtr
}
*d = nil
return nil
case *[]byte:
if d == nil {
return errNilPtr
}
*d = nil
return nil
case *RawBytes:
if d == nil {
return errNilPtr
}
*d = nil
return nil
case *time.Time:
return nil
}
}
var sv reflect.Value
switch d := dest.(type) {
case *string:
sv = reflect.ValueOf(src)
switch sv.Kind() {
case reflect.Bool,
reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
reflect.Float32, reflect.Float64:
*d = fmt.Sprintf("%v", src)
return nil
}
case *[]byte:
sv = reflect.ValueOf(src)
switch sv.Kind() {
case reflect.Bool,
reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
reflect.Float32, reflect.Float64:
*d = []byte(fmt.Sprintf("%v", src))
return nil
}
case *RawBytes:
sv = reflect.ValueOf(src)
switch sv.Kind() {
case reflect.Bool,
reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
reflect.Float32, reflect.Float64:
*d = RawBytes(fmt.Sprintf("%v", src))
return nil
}
case *bool:
bv, err := driver.Bool.ConvertValue(src)
if err == nil {
*d = bv.(bool)
}
return err
case *interface{}:
*d = src
return nil
}
if scanner, ok := dest.(sql.Scanner); ok {
return scanner.Scan(src)
}
dpv := reflect.ValueOf(dest)
if dpv.Kind() != reflect.Ptr {
return errors.New("destination not a pointer")
}
if dpv.IsNil() {
return errNilPtr
}
if !sv.IsValid() {
sv = reflect.ValueOf(src)
}
//if types are the same
dv := reflect.Indirect(dpv)
if dv.Kind() == sv.Kind() {
dv.Set(sv)
return nil
}
//My addition.
//This is added to the original implementation from go source
//Intention is to skip string conversion for most common cases.
//Types are almost the same e.g. int -> int32
switch dv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
switch sv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
dv.SetInt(sv.Int())
return nil
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
switch sv.Kind() {
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
dv.SetUint(sv.Uint())
return nil
}
case reflect.Float32, reflect.Float64:
switch sv.Kind() {
case reflect.Float32, reflect.Float64:
dv.SetFloat(sv.Float())
return nil
}
}
//convert to string than back
switch dv.Kind() {
case reflect.Ptr:
if src == nil {
dv.Set(reflect.Zero(dv.Type()))
return nil
} else {
dv.Set(reflect.New(dv.Type().Elem()))
return convertAssign(dv.Interface(), src)
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
s := asString(src)
i64, err := strconv.ParseInt(s, 10, dv.Type().Bits())
if err != nil {
return fmt.Errorf("converting string %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:
s := asString(src)
u64, err := strconv.ParseUint(s, 10, dv.Type().Bits())
if err != nil {
return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err)
}
dv.SetUint(u64)
return nil
case reflect.Float32, reflect.Float64:
s := asString(src)
f64, err := strconv.ParseFloat(s, dv.Type().Bits())
if err != nil {
return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err)
}
dv.SetFloat(f64)
return nil
}
return fmt.Errorf("unsupported driver -> Scan pair: %T -> %T", src, dest)
}
func cloneBytes(b []byte) []byte {
if b == nil {
return nil
} else {
c := make([]byte, len(b))
copy(c, b)
return c
}
}
func asString(src interface{}) string {
switch v := src.(type) {
case string:
return v
case []byte:
return string(v)
}
return fmt.Sprintf("%v", src)
}