internal/impl: allow reflection on typed nil pointers
Similar to how generated messages allow you to call Get methods on a
nil pointer, we permit similar functionality when protobuf reflection
is used on a nil pointer.
Change-Id: Ie2f596d39105c191073b42d7d689525c3b715240
Reviewed-on: https://go-review.googlesource.com/c/152021
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/internal/impl/message_field.go b/internal/impl/message_field.go
index 681c918..c55cbc8 100644
--- a/internal/impl/message_field.go
+++ b/internal/impl/message_field.go
@@ -51,25 +51,28 @@
// typed nil pointer to one of the wrapper structs.
has: func(p pointer) bool {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return false
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot {
return false
}
return true
},
get: func(p pointer) pref.Value {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return defaultValueOf(fd)
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot {
- if fd.Kind() == pref.MessageKind || fd.Kind() == pref.GroupKind {
- return pref.Value{}
- }
- return fd.Default()
+ return defaultValueOf(fd)
}
rv = rv.Elem().Elem().Field(0)
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot {
rv.Set(reflect.New(ot))
}
@@ -77,7 +80,7 @@
rv.Set(conv.GoValueOf(v))
},
clear: func(p pointer) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot {
return
}
@@ -85,7 +88,7 @@
},
mutable: func(p pointer) pref.Mutable {
// Mutable is only valid for messages and panics for other kinds.
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() || rv.Elem().Type().Elem() != ot {
rv.Set(reflect.New(ot))
}
@@ -110,23 +113,30 @@
// TODO: Implement unsafe fast path?
return fieldInfo{
has: func(p pointer) bool {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return false
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return rv.Len() > 0
},
get: func(p pointer) pref.Value {
- v := p.apply(fieldOffset).asType(fs.Type).Interface()
+ if p.IsNil() {
+ v := reflect.Zero(reflect.PtrTo(fs.Type)).Interface()
+ return pref.ValueOf(pvalue.MapOf(v, keyConv, valConv))
+ }
+ v := p.Apply(fieldOffset).AsIfaceOf(fs.Type)
return pref.ValueOf(pvalue.MapOf(v, keyConv, valConv))
},
set: func(p pointer, v pref.Value) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.ValueOf(v.Map().(pvalue.Unwrapper).ProtoUnwrap()).Elem())
},
clear: func(p pointer) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
mutable: func(p pointer) pref.Mutable {
- v := p.apply(fieldOffset).asType(fs.Type).Interface()
+ v := p.Apply(fieldOffset).AsIfaceOf(fs.Type)
return pvalue.MapOf(v, keyConv, valConv)
},
}
@@ -142,23 +152,30 @@
// TODO: Implement unsafe fast path?
return fieldInfo{
has: func(p pointer) bool {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return false
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return rv.Len() > 0
},
get: func(p pointer) pref.Value {
- v := p.apply(fieldOffset).asType(fs.Type).Interface()
+ if p.IsNil() {
+ v := reflect.Zero(reflect.PtrTo(fs.Type)).Interface()
+ return pref.ValueOf(pvalue.ListOf(v, conv))
+ }
+ v := p.Apply(fieldOffset).AsIfaceOf(fs.Type)
return pref.ValueOf(pvalue.ListOf(v, conv))
},
set: func(p pointer, v pref.Value) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.ValueOf(v.List().(pvalue.Unwrapper).ProtoUnwrap()).Elem())
},
clear: func(p pointer) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
mutable: func(p pointer) pref.Mutable {
- v := p.apply(fieldOffset).asType(fs.Type).Interface()
+ v := p.Apply(fieldOffset).AsIfaceOf(fs.Type)
return pvalue.ListOf(v, conv)
},
}
@@ -182,7 +199,10 @@
// TODO: Implement unsafe fast path?
return fieldInfo{
has: func(p pointer) bool {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return false
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if nullable {
return !rv.IsNil()
}
@@ -202,14 +222,13 @@
}
},
get: func(p pointer) pref.Value {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return defaultValueOf(fd)
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if nullable {
if rv.IsNil() {
- pv := fd.Default()
- if fd.Kind() == pref.BytesKind && len(pv.Bytes()) > 0 {
- return pref.ValueOf(append([]byte(nil), pv.Bytes()...)) // copy default bytes for safety
- }
- return pv
+ return defaultValueOf(fd)
}
if rv.Kind() == reflect.Ptr {
rv = rv.Elem()
@@ -218,7 +237,7 @@
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if nullable && rv.Kind() == reflect.Ptr {
if rv.IsNil() {
rv.Set(reflect.New(ft))
@@ -231,7 +250,7 @@
}
},
clear: func(p pointer) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
mutable: func(p pointer) pref.Mutable {
@@ -247,30 +266,36 @@
// TODO: Implement unsafe fast path?
return fieldInfo{
has: func(p pointer) bool {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return false
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
return !rv.IsNil()
},
get: func(p pointer) pref.Value {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ if p.IsNil() {
+ return pref.Value{}
+ }
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() {
return pref.Value{}
}
return conv.PBValueOf(rv)
},
set: func(p pointer, v pref.Value) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(conv.GoValueOf(v))
if rv.IsNil() {
panic("invalid nil pointer")
}
},
clear: func(p pointer) {
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
rv.Set(reflect.Zero(rv.Type()))
},
mutable: func(p pointer) pref.Mutable {
// Mutable is only valid for messages and panics for other kinds.
- rv := p.apply(fieldOffset).asType(fs.Type).Elem()
+ rv := p.Apply(fieldOffset).AsValueOf(fs.Type).Elem()
if rv.IsNil() {
pv := pref.ValueOf(conv.MessageType.New().ProtoReflect())
rv.Set(conv.GoValueOf(pv))
@@ -279,3 +304,15 @@
},
}
}
+
+// defaultValueOf returns the default value for the field.
+func defaultValueOf(fd pref.FieldDescriptor) pref.Value {
+ if fd == nil {
+ return pref.Value{}
+ }
+ pv := fd.Default() // invalid Value for messages and repeated fields
+ if fd.Kind() == pref.BytesKind && pv.IsValid() && len(pv.Bytes()) > 0 {
+ return pref.ValueOf(append([]byte(nil), pv.Bytes()...)) // copy default bytes for safety
+ }
+ return pv
+}