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// 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.
// Type conversions for Scan.
package sql
import (
"errors"
"fmt"
"reflect"
"strconv"
)
// 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. Fall through.
switch s := src.(type) {
case string:
switch d := dest.(type) {
case *string:
*d = s
return nil
}
case []byte:
switch d := dest.(type) {
case *string:
*d = string(s)
return nil
case *[]byte:
*d = s
return nil
}
}
sv := reflect.ValueOf(src)
switch d := dest.(type) {
case *string:
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
}
}
if scanner, ok := dest.(ScannerInto); ok {
return scanner.ScanInto(src)
}
dpv := reflect.ValueOf(dest)
if dpv.Kind() != reflect.Ptr {
return errors.New("destination not a pointer")
}
dv := reflect.Indirect(dpv)
if dv.Kind() == sv.Kind() {
dv.Set(sv)
return nil
}
switch dv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if s, ok := asString(src); ok {
i64, err := strconv.Atoi64(s)
if err != nil {
return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err)
}
if dv.OverflowInt(i64) {
return fmt.Errorf("string %q overflows %s", s, dv.Kind())
}
dv.SetInt(i64)
return nil
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if s, ok := asString(src); ok {
u64, err := strconv.Atoui64(s)
if err != nil {
return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err)
}
if dv.OverflowUint(u64) {
return fmt.Errorf("string %q overflows %s", s, dv.Kind())
}
dv.SetUint(u64)
return nil
}
}
return fmt.Errorf("unsupported driver -> Scan pair: %T -> %T", src, dest)
}
func asString(src interface{}) (s string, ok bool) {
switch v := src.(type) {
case string:
return v, true
case []byte:
return string(v), true
}
return "", false
}
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