database/sql: treat pointers as nullable types like encoding/json
- convert from nil pointers to the nil interface{}
- dereference non-nil pointers
- convert from nil interface{}s to nil pointers
- allocate pointers for non-nil interface{}s
- tests for all of the above
R=golang-dev, bradfitz, rsc, rogpeppe
CC=golang-dev
https://golang.org/cl/5630052
diff --git a/src/pkg/database/sql/convert.go b/src/pkg/database/sql/convert.go
index 4924ac1..31ff47f 100644
--- a/src/pkg/database/sql/convert.go
+++ b/src/pkg/database/sql/convert.go
@@ -110,6 +110,14 @@
}
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())
diff --git a/src/pkg/database/sql/convert_test.go b/src/pkg/database/sql/convert_test.go
index 34ee939..9c362d7 100644
--- a/src/pkg/database/sql/convert_test.go
+++ b/src/pkg/database/sql/convert_test.go
@@ -13,6 +13,7 @@
)
var someTime = time.Unix(123, 0)
+var answer int64 = 42
type conversionTest struct {
s, d interface{} // source and destination
@@ -27,6 +28,8 @@
wantbool bool // used if d is of type *bool
wanterr string
wantiface interface{}
+ wantptr *int64 // if non-nil, *d's pointed value must be equal to *wantptr
+ wantnil bool // if true, *d must be *int64(nil)
}
// Target variables for scanning into.
@@ -42,6 +45,7 @@
scanf32 float32
scanf64 float64
scantime time.Time
+ scanptr *int64
scaniface interface{}
)
@@ -98,6 +102,10 @@
{s: "1.5", d: &scanf32, wantf32: float32(1.5)},
{s: "1.5", d: &scanf64, wantf64: float64(1.5)},
+ // Pointers
+ {s: interface{}(nil), d: &scanptr, wantnil: true},
+ {s: int64(42), d: &scanptr, wantptr: &answer},
+
// To interface{}
{s: float64(1.5), d: &scaniface, wantiface: float64(1.5)},
{s: int64(1), d: &scaniface, wantiface: int64(1)},
@@ -107,6 +115,10 @@
{s: nil, d: &scaniface},
}
+func intPtrValue(intptr interface{}) interface{} {
+ return reflect.Indirect(reflect.Indirect(reflect.ValueOf(intptr))).Int()
+}
+
func intValue(intptr interface{}) int64 {
return reflect.Indirect(reflect.ValueOf(intptr)).Int()
}
@@ -162,6 +174,16 @@
if !ct.wanttime.IsZero() && !ct.wanttime.Equal(timeValue(ct.d)) {
errf("want time %v, got %v", ct.wanttime, timeValue(ct.d))
}
+ if ct.wantnil && *ct.d.(**int64) != nil {
+ errf("want nil, got %v", intPtrValue(ct.d))
+ }
+ if ct.wantptr != nil {
+ if *ct.d.(**int64) == nil {
+ errf("want pointer to %v, got nil", *ct.wantptr)
+ } else if *ct.wantptr != intPtrValue(ct.d) {
+ errf("want pointer to %v, got %v", *ct.wantptr, intPtrValue(ct.d))
+ }
+ }
if ifptr, ok := ct.d.(*interface{}); ok {
if !reflect.DeepEqual(ct.wantiface, scaniface) {
errf("want interface %#v, got %#v", ct.wantiface, scaniface)
diff --git a/src/pkg/database/sql/driver/types.go b/src/pkg/database/sql/driver/types.go
index f383885..ce3c943 100644
--- a/src/pkg/database/sql/driver/types.go
+++ b/src/pkg/database/sql/driver/types.go
@@ -248,6 +248,13 @@
rv := reflect.ValueOf(v)
switch rv.Kind() {
+ case reflect.Ptr:
+ // indirect pointers
+ if rv.IsNil() {
+ return nil, nil
+ } else {
+ return defaultConverter{}.ConvertValue(rv.Elem().Interface())
+ }
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return rv.Int(), nil
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32:
diff --git a/src/pkg/database/sql/driver/types_test.go b/src/pkg/database/sql/driver/types_test.go
index 966bc6b..ab82bca 100644
--- a/src/pkg/database/sql/driver/types_test.go
+++ b/src/pkg/database/sql/driver/types_test.go
@@ -18,6 +18,7 @@
}
var now = time.Now()
+var answer int64 = 42
var valueConverterTests = []valueConverterTest{
{Bool, "true", true, ""},
@@ -37,6 +38,9 @@
{c: Bool, in: "foo", err: "sql/driver: couldn't convert \"foo\" into type bool"},
{c: Bool, in: 2, err: "sql/driver: couldn't convert 2 into type bool"},
{DefaultParameterConverter, now, now, ""},
+ {DefaultParameterConverter, (*int64)(nil), nil, ""},
+ {DefaultParameterConverter, &answer, answer, ""},
+ {DefaultParameterConverter, &now, now, ""},
}
func TestValueConverters(t *testing.T) {
