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reflect: adjust access to unexported embedded structs

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This CL changes reflect to allow access to exported fields and
methods in unexported embedded structs for gccgo and after gc
has been adjusted to disallow access to embedded unexported structs.

Adresses #12367, #7363, #11007, and #7247.

Change-Id: If80536eab35abcd25300d8ddc2d27d5c42d7e78e
Reviewed-on: https://go-review.googlesource.com/14010
Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Marcel van Lohuizen 2015-08-28 09:33:51 +02:00
parent fb7178e7cc
commit adf9b30e55
3 changed files with 20 additions and 13 deletions
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4
src/reflect/export_test.go
View File

@ -8,13 +8,13 @@ import "unsafe"
// MakeRO returns a copy of v with the read-only flag set. // MakeRO returns a copy of v with the read-only flag set.
func MakeRO(v Value) Value { func MakeRO(v Value) Value {
v.flag |= flagRO v.flag |= flagStickyRO
return v return v
} }
// IsRO reports whether v's read-only flag is set. // IsRO reports whether v's read-only flag is set.
func IsRO(v Value) bool { func IsRO(v Value) bool {
return v.flag&flagRO != 0 return v.flag&flagStickyRO != 0
} }
var CallGC = &callGC var CallGC = &callGC

2
src/reflect/type.go
View File

@ -496,7 +496,7 @@ func (t *uncommonType) Method(i int) (m Method) {
fl := flag(Func) fl := flag(Func)
if p.pkgPath != nil { if p.pkgPath != nil {
m.PkgPath = *p.pkgPath m.PkgPath = *p.pkgPath
fl |= flagRO fl |= flagStickyRO
} }
mt := p.typ mt := p.typ
m.Type = mt m.Type = mt

27
src/reflect/value.go
View File

@ -44,7 +44,8 @@ type Value struct {
// flag holds metadata about the value. // flag holds metadata about the value.
// The lowest bits are flag bits: // The lowest bits are flag bits:
// - flagRO: obtained via unexported field, so read-only // - flagStickyRO: obtained via unexported not embedded field, so read-only
// - flagEmbedRO: obtained via unexported embedded field, so read-only
// - flagIndir: val holds a pointer to the data // - flagIndir: val holds a pointer to the data
// - flagAddr: v.CanAddr is true (implies flagIndir) // - flagAddr: v.CanAddr is true (implies flagIndir)
// - flagMethod: v is a method value. // - flagMethod: v is a method value.
@ -67,11 +68,13 @@ type flag uintptr
const ( const (
flagKindWidth = 5 // there are 27 kinds flagKindWidth = 5 // there are 27 kinds
flagKindMask flag = 1<<flagKindWidth - 1 flagKindMask flag = 1<<flagKindWidth - 1
flagRO flag = 1 << 5 flagStickyRO flag = 1 << 5
flagIndir flag = 1 << 6 flagEmbedRO flag = 1 << 6
flagAddr flag = 1 << 7 flagIndir flag = 1 << 7
flagMethod flag = 1 << 8 flagAddr flag = 1 << 8
flagMethodShift = 9 flagMethod flag = 1 << 9
flagMethodShift = 10
flagRO flag = flagStickyRO | flagEmbedRO
) )
func (f flag) kind() Kind { func (f flag) kind() Kind {
@ -745,11 +748,15 @@ func (v Value) Field(i int) Value {
field := &tt.fields[i] field := &tt.fields[i]
typ := field.typ typ := field.typ
// Inherit permission bits from v. // Inherit permission bits from v, but clear flagEmbedRO.
fl := v.flag&(flagRO|flagIndir|flagAddr) | flag(typ.Kind()) fl := v.flag&(flagStickyRO|flagIndir|flagAddr) | flag(typ.Kind())
// Using an unexported field forces flagRO. // Using an unexported field forces flagRO.
if field.pkgPath != nil { if field.pkgPath != nil {
fl |= flagRO if field.name == nil {
fl |= flagEmbedRO
} else {
fl |= flagStickyRO
}
} }
// Either flagIndir is set and v.ptr points at struct, // Either flagIndir is set and v.ptr points at struct,
// or flagIndir is not set and v.ptr is the actual struct data. // or flagIndir is not set and v.ptr is the actual struct data.
@ -1104,7 +1111,7 @@ func (v Value) Method(i int) Value {
if v.typ.Kind() == Interface && v.IsNil() { if v.typ.Kind() == Interface && v.IsNil() {
panic("reflect: Method on nil interface value") panic("reflect: Method on nil interface value")
} }
fl := v.flag & (flagRO | flagIndir) fl := v.flag & (flagStickyRO | flagIndir) // Clear flagEmbedRO
fl |= flag(Func) fl |= flag(Func)
fl |= flag(i)<<flagMethodShift | flagMethod fl |= flag(i)<<flagMethodShift | flagMethod
return Value{v.typ, v.ptr, fl} return Value{v.typ, v.ptr, fl}