re PR go/66138 (json decoder Decode function fails for some structure return values)

	PR go/66138
    reflect, encoding/json, encoding/xml: fix unexported embedded structs
    
    Bring in three changes from the master Go repository.  These changes
    will be in Go 1.6, but they are appropriate for gccgo now because they
    resolve a long-standing discrepancy between how gc and gccgo handle the
    PkgPath field for embedded unexported struct fields.  The core issue is
    described at https://golang.org/cl/7247.  This has been reported against
    gccgo as https://gcc.gnu.org/PR66138.
    
    The three changes being brought over are:
    
    https://golang.org/cl/14010
    
    reflect: adjust access to unexported embedded structs
    
    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.
    
    https://golang.org/cl/14011
    
    encoding/json: check for exported fields in embedded structs
    
    Addresses issue #12367.
    
    https://golang.org/cl/14012
    
    encoding/xml: check for exported fields in embedded structs
    
    Addresses issue #12367.
    
    Reviewed-on: https://go-review.googlesource.com/16723

From-SVN: r229907

1 files changed, 18 insertions, 11 deletions

diff --git a/libgo/go/reflect/value.go b/libgo/go/reflect/value.go
index a924d86..8374370 100644
--- a/libgo/go/reflect/value.go
+++ b/libgo/go/reflect/value.go
@@ -44,7 +44,8 @@ type Value struct {
 
 	// flag holds metadata about the value.
 	// 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
 	//	- flagAddr: v.CanAddr is true (implies flagIndir)
 	//	- flagMethod: v is a method value.
@@ -67,12 +68,14 @@ type flag uintptr
 const (
 	flagKindWidth        = 5 // there are 27 kinds
 	flagKindMask    flag = 1<<flagKindWidth - 1
-	flagRO          flag = 1 << 5
-	flagIndir       flag = 1 << 6
-	flagAddr        flag = 1 << 7
-	flagMethod      flag = 1 << 8
-	flagMethodFn    flag = 1 << 9 // gccgo: first fn parameter is always pointer
-	flagMethodShift      = 10
+	flagStickyRO    flag = 1 << 5
+	flagEmbedRO     flag = 1 << 6
+	flagIndir       flag = 1 << 7
+	flagAddr        flag = 1 << 8
+	flagMethod      flag = 1 << 9
+	flagMethodFn    flag = 1 << 10 // gccgo: first fn parameter is always pointer
+	flagMethodShift      = 11
+	flagRO          flag = flagStickyRO | flagEmbedRO
 )
 
 func (f flag) kind() Kind {
@@ -617,11 +620,15 @@ func (v Value) Field(i int) Value {
 	field := &tt.fields[i]
 	typ := field.typ
 
-	// Inherit permission bits from v.
-	fl := v.flag&(flagRO|flagIndir|flagAddr) | flag(typ.Kind())
+	// Inherit permission bits from v, but clear flagEmbedRO.
+	fl := v.flag&(flagStickyRO|flagIndir|flagAddr) | flag(typ.Kind())
 	// Using an unexported field forces flagRO.
 	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,
 	// or flagIndir is not set and v.ptr is the actual struct data.
@@ -986,7 +993,7 @@ func (v Value) Method(i int) Value {
 	if v.typ.Kind() == Interface && v.IsNil() {
 		panic("reflect: Method on nil interface value")
 	}
-	fl := v.flag & (flagRO | flagIndir)
+	fl := v.flag & (flagStickyRO | flagIndir) // Clear flagEmbedRO
 	fl |= flag(Func)
 	fl |= flag(i)<<flagMethodShift | flagMethod
 	return Value{v.typ, v.ptr, fl}