// 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 ( "database/sql/driver" "errors" "fmt" "reflect" "strconv") var errNilPtr = errors.New("destination pointer is nil") // embedded in descriptive error // driverArgs converts arguments from callers of Stmt.Exec and// Stmt.Query into driver Values.//// The statement ds may be nil, if no statement is available.func driverArgs(ds *driverStmt, args []interface{}) ([]driver.Value, error) { dargs := make([]driver.Value, len(args)) var si driver.Stmt if ds != nil { si = ds.si } cc, ok := si.(driver.ColumnConverter) // Normal path, for a driver.Stmt that is not a ColumnConverter. if !ok { for n, arg := range args { var err error dargs[n], err = driver.DefaultParameterConverter.ConvertValue(arg) if err != nil { return nil, fmt.Errorf("sql: converting Exec argument #%d's type: %v", n, err) } } return dargs, nil } // Let the Stmt convert its own arguments. for n, arg := range args { // First, see if the value itself knows how to convert // itself to a driver type. For example, a NullString // struct changing into a string or nil. if svi, ok := arg.(driver.Valuer); ok { sv, err := svi.Value() if err != nil { return nil, fmt.Errorf("sql: argument index %d from Value: %v", n, err) } if !driver.IsValue(sv) { return nil, fmt.Errorf("sql: argument index %d: non-subset type %T returned from Value", n, sv) } arg = sv } // Second, ask the column to sanity check itself. For // example, drivers might use this to make sure that // an int64 values being inserted into a 16-bit // integer field is in range (before getting // truncated), or that a nil can't go into a NOT NULL // column before going across the network to get the // same error. var err error ds.Lock() dargs[n], err = cc.ColumnConverter(n).ConvertValue(arg) ds.Unlock() if err != nil { return nil, fmt.Errorf("sql: converting argument #%d's type: %v", n, err) } if !driver.IsValue(dargs[n]) { return nil, fmt.Errorf("sql: driver ColumnConverter error converted %T to unsupported type %T", arg, dargs[n]) } } return dargs, nil} // 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 } } 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 = asString(src) return nil } case *[]byte: sv = reflect.ValueOf(src) if b, ok := asBytes(nil, sv); ok { *d = b return nil } case *RawBytes: sv = reflect.ValueOf(src) if b, ok := asBytes([]byte(*d)[:0], sv); ok { *d = RawBytes(b) 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.(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) } dv := reflect.Indirect(dpv) if sv.IsValid() && sv.Type().AssignableTo(dv.Type()) { dv.Set(sv) return nil } if dv.Kind() == sv.Kind() && sv.Type().ConvertibleTo(dv.Type()) { dv.Set(sv.Convert(dv.Type())) return nil } 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) } rv := reflect.ValueOf(src) switch rv.Kind() { case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: return strconv.FormatInt(rv.Int(), 10) case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: return strconv.FormatUint(rv.Uint(), 10) case reflect.Float64: return strconv.FormatFloat(rv.Float(), 'g', -1, 64) case reflect.Float32: return strconv.FormatFloat(rv.Float(), 'g', -1, 32) case reflect.Bool: return strconv.FormatBool(rv.Bool()) } return fmt.Sprintf("%v", src)} func asBytes(buf []byte, rv reflect.Value) (b []byte, ok bool) { switch rv.Kind() { case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: return strconv.AppendInt(buf, rv.Int(), 10), true case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: return strconv.AppendUint(buf, rv.Uint(), 10), true case reflect.Float32: return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 32), true case reflect.Float64: return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 64), true case reflect.Bool: return strconv.AppendBool(buf, rv.Bool()), true case reflect.String: s := rv.String() return append(buf, s...), true } return}
// 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 (
"database/sql/driver"
"errors"
"fmt"
"reflect"
"strconv"
)
var errNilPtr = errors.New("destination pointer is nil") // embedded in descriptive error
// driverArgs converts arguments from callers of Stmt.Exec and
// Stmt.Query into driver Values.
//
// The statement ds may be nil, if no statement is available.
func driverArgs(ds *driverStmt, args []interface{}) ([]driver.Value, error) {
dargs := make([]driver.Value, len(args))
var si driver.Stmt
if ds != nil {
si = ds.si
}
cc, ok := si.(driver.ColumnConverter)
// Normal path, for a driver.Stmt that is not a ColumnConverter.
if !ok {
for n, arg := range args {
var err error
dargs[n], err = driver.DefaultParameterConverter.ConvertValue(arg)
if err != nil {
return nil, fmt.Errorf("sql: converting Exec argument #%d's type: %v", n, err)
}
}
return dargs, nil
}
// Let the Stmt convert its own arguments.
for n, arg := range args {
// First, see if the value itself knows how to convert
// itself to a driver type. For example, a NullString
// struct changing into a string or nil.
if svi, ok := arg.(driver.Valuer); ok {
sv, err := svi.Value()
if err != nil {
return nil, fmt.Errorf("sql: argument index %d from Value: %v", n, err)
}
if !driver.IsValue(sv) {
return nil, fmt.Errorf("sql: argument index %d: non-subset type %T returned from Value", n, sv)
}
arg = sv
}
// Second, ask the column to sanity check itself. For
// example, drivers might use this to make sure that
// an int64 values being inserted into a 16-bit
// integer field is in range (before getting
// truncated), or that a nil can't go into a NOT NULL
// column before going across the network to get the
// same error.
var err error
ds.Lock()
dargs[n], err = cc.ColumnConverter(n).ConvertValue(arg)
ds.Unlock()
if err != nil {
return nil, fmt.Errorf("sql: converting argument #%d's type: %v", n, err)
}
if !driver.IsValue(dargs[n]) {
return nil, fmt.Errorf("sql: driver ColumnConverter error converted %T to unsupported type %T",
arg, dargs[n])
}
}
return dargs, nil
}
// 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
}
}
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 = asString(src)
return nil
}
case *[]byte:
sv = reflect.ValueOf(src)
if b, ok := asBytes(nil, sv); ok {
*d = b
return nil
}
case *RawBytes:
sv = reflect.ValueOf(src)
if b, ok := asBytes([]byte(*d)[:0], sv); ok {
*d = RawBytes(b)
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.(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)
}
dv := reflect.Indirect(dpv)
if sv.IsValid() && sv.Type().AssignableTo(dv.Type()) {
dv.Set(sv)
return nil
}
if dv.Kind() == sv.Kind() && sv.Type().ConvertibleTo(dv.Type()) {
dv.Set(sv.Convert(dv.Type()))
return nil
}
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)
}
rv := reflect.ValueOf(src)
switch rv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return strconv.FormatInt(rv.Int(), 10)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return strconv.FormatUint(rv.Uint(), 10)
case reflect.Float64:
return strconv.FormatFloat(rv.Float(), 'g', -1, 64)
case reflect.Float32:
return strconv.FormatFloat(rv.Float(), 'g', -1, 32)
case reflect.Bool:
return strconv.FormatBool(rv.Bool())
}
return fmt.Sprintf("%v", src)
}
func asBytes(buf []byte, rv reflect.Value) (b []byte, ok bool) {
switch rv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return strconv.AppendInt(buf, rv.Int(), 10), true
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return strconv.AppendUint(buf, rv.Uint(), 10), true
case reflect.Float32:
return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 32), true
case reflect.Float64:
return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 64), true
case reflect.Bool:
return strconv.AppendBool(buf, rv.Bool()), true
case reflect.String:
s := rv.String()
return append(buf, s...), true
}
return
}