go1.3: add rtype.zero, Value.scalar

ZxxLang · Feb 14, 2015 · cde17ff · cde17ff
1 parent e523a04
commit cde17ff
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Showing 5 changed files with 19 additions and 8 deletions.
diff --git a/reflect.go b/reflect.go
@@ -12,8 +12,9 @@ func (k Kind) String() string {
 }
 
 type reflectValue struct {
-	typ *Type //*rtype
-	val unsafe.Pointer
+	typ    *Type //*rtype
+	val    unsafe.Pointer
+	scalar uintptr // go1.3
 	flag
 }
 
@@ -23,6 +24,7 @@ func FromValue(v reflect.Value) Value {
 		rv.typ,
 		sur{
 			rv.val,
+			rv.scalar,
 			rv.flag,
 			unsafe.Pointer(rv.typ),
 		},

diff --git a/surface.go b/surface.go
@@ -80,6 +80,12 @@ type sur struct {
 	// knows that val could be a pointer.
 	val unsafe.Pointer
 
+	// Non-pointer-valued data.  When the data is smaller
+	// than a word, it begins at the first byte (in the memory
+	// address sense) of this field.
+	// Valid when flagIndir is not set and typ.pointers() is false.
+	scalar uintptr // go1.3
+
 	// flag holds metadata about the value.
 	// The lowest bits are flag bits:
 	//	- flagRO: obtained via unexported field, so read-only

diff --git a/surface_test.go b/surface_test.go
@@ -46,7 +46,7 @@ func TestStructAndFields(t *testing.T) {
 		wt.Equal(rt.String(), sv.Type.String())
 		wt.Equal(rt.PkgPath(), sv.Type.PkgPath())
 
-		wt.Equal(rt.NumField(), st.NumField())
+		wt.Equal(rt.NumField(), st.NumField(), i, s)
 		wt.Equal(rv.Interface(), sv.Interface())
 
 		wt.Equal(rv.CanSet(), sv.CanSet())

diff --git a/type.go b/type.go
@@ -67,6 +67,8 @@ type Type struct {
 	string        *string        // string form; unnecessary but undeniably useful
 	*uncommonType                // (relatively) uncommon fields
 	PtrToThis     *Type          // type for pointer to this type, if used in binary or has methods
+	// go 1.3
+	zero unsafe.Pointer // pointer to zero value
 }
 
 // uncommonType is present only for types with names or methods

diff --git a/value.go b/value.go
@@ -128,7 +128,7 @@ func (v Value) Surface() Interface {
 	if typ != nil && typ.Size > ptrSize {
 		fl |= flagIndir
 	}
-	return Interface{ifacetype, sur{val, fl, v.typ}, typ}
+	return Interface{ifacetype, sur{val, v.scalar, fl, v.typ}, typ}
 }
 
 func (v Interface) InterfaceData() [2]uintptr {
@@ -155,7 +155,7 @@ func (v Ptr) Elem() Value {
 	fl := v.flag&flagRO | flagIndir | flagAddr
 	fl |= flag(typ.Kind() << flagKindShift)
 
-	return Value{typ, sur{val, fl, unsafe.Pointer(tt.Elem)}}
+	return Value{typ, sur{val, v.scalar, fl, unsafe.Pointer(tt.Elem)}}
 }
 
 // Indirect returns the value that v points to.
@@ -238,7 +238,7 @@ func (v Array) Index(i int) Value {
 		// Direct.  Discard leading bytes.
 		val = unsafe.Pointer(uintptr(v.val) >> (offset * 8))
 	}
-	return Value{typ, sur{val, fl, unsafe.Pointer(tt.Elem)}}
+	return Value{typ, sur{val, v.scalar, fl, unsafe.Pointer(tt.Elem)}}
 
 }
 func (v Slice) Index(i int) Value {
@@ -252,7 +252,7 @@ func (v Slice) Index(i int) Value {
 	typ := v.Type.Elem
 	fl |= flag(typ.Kind()) << flagKindShift
 	val := unsafe.Pointer(s.Data + uintptr(i)*typ.Size)
-	return Value{typ, sur{val, fl, unsafe.Pointer(v.Type.Elem)}}
+	return Value{typ, sur{val, v.scalar, fl, unsafe.Pointer(v.Type.Elem)}}
 }
 
 func (v Struct) Field(i int) Value {
@@ -286,7 +286,7 @@ func (v Struct) field(i int) Value {
 		val = unsafe.Pointer(uintptr(v.val) >> (field.offset * 8))
 	}
 
-	return Value{typ, sur{val, fl, unsafe.Pointer(field.Type)}}
+	return Value{typ, sur{val, v.scalar, fl, unsafe.Pointer(field.Type)}}
 }
 
 // FieldByIndex returns the nested field corresponding to index.
@@ -340,6 +340,7 @@ func ValueOf(i interface{}) Value {
 		typ,
 		sur{
 			unsafe.Pointer(eface.word),
+			uintptr(eface.word),
 			fl,
 			unsafe.Pointer(eface.Type),
 		},