make a description of the slice header public

R=rsc
DELTA=18  (3 added, 0 deleted, 15 changed)
OCL=31086
CL=31094

diff --git a/src/pkg/reflect/value.go b/src/pkg/reflect/value.go
index f59e3a27292f3161db73d6f49cafd9e779cc7c80..26ba6cb6b493df126a8cbbab0140f31af138840f 100644 (file)
--- a/src/pkg/reflect/value.go
+++ b/src/pkg/reflect/value.go
@@ -563,17 +563,20 @@ func copyArray(dst ArrayValue, src ArrayValue, n int);
                        uint32  cap;
                };
 */
-type runtimeSlice struct {
-       data    Addr;
-       len     uint32;
-       cap     uint32;
+
+// A published version of the Slice header so that clients don't have a separate copy of the definition.
+// SliceHeader is not useful to clients unless they use unsafe.Pointer.
+type SliceHeader struct {
+       Data    uintptr;
+       Len     uint32;
+       Cap     uint32;
 }
 
 type sliceValueStruct struct {
        commonValue;
        elemtype        Type;
        elemsize        int;
-       slice *runtimeSlice;
+       slice *SliceHeader;
 }
 
 func (v *sliceValueStruct) IsSlice() bool {
@@ -581,18 +584,18 @@ func (v *sliceValueStruct) IsSlice() bool {
 }
 
 func (v *sliceValueStruct) Len() int {
-       return int(v.slice.len);
+       return int(v.slice.Len);
 }
 
 func (v *sliceValueStruct) Cap() int {
-       return int(v.slice.cap);
+       return int(v.slice.Cap);
 }
 
 func (v *sliceValueStruct) SetLen(len int) {
        if len > v.Cap() {
                panicln("reflect: sliceValueStruct.SetLen", len, v.Cap());
        }
-       v.slice.len = uint32(len);
+       v.slice.Len = uint32(len);
 }
 
 func (v *sliceValueStruct) Set(src ArrayValue) {
@@ -607,7 +610,7 @@ func (v *sliceValueStruct) Set(src ArrayValue) {
 }
 
 func (v *sliceValueStruct) Elem(i int) Value {
-       data_uint := uintptr(v.slice.data) + uintptr(i * v.elemsize);
+       data_uint := v.slice.Data + uintptr(i * v.elemsize);
        return newValueAddr(v.elemtype, Addr(data_uint));
 }
 
@@ -616,7 +619,7 @@ func (v *sliceValueStruct) CopyFrom(src ArrayValue, n int) {
 }
 
 func (v *sliceValueStruct) IsNil() bool {
-       return uintptr(v.slice.data) == 0
+       return v.slice.Data == 0
 }
 
 type arrayValueStruct struct {
@@ -668,7 +671,7 @@ func arrayCreator(typ Type, addr Addr) Value {
                v.typ = typ;
                v.elemtype = arraytype.Elem();
                v.elemsize = v.elemtype.Size();
-               v.slice = (*runtimeSlice)(addr);
+               v.slice = (*SliceHeader)(addr);
                return v;
        }
        v := new(arrayValueStruct);
@@ -897,15 +900,15 @@ func NewSliceValue(typ ArrayType, len, cap int) ArrayValue {
                return nil
        }
 
-       array := new(runtimeSlice);
+       array := new(SliceHeader);
        size := typ.Elem().Size() * cap;
        if size == 0 {
                size = 1;
        }
        data := make([]uint8, size);
-       array.data = Addr(&data[0]);
-       array.len = uint32(len);
-       array.cap = uint32(cap);
+       array.Data = uintptr(Addr(&data[0]));
+       array.Len = uint32(len);
+       array.Cap = uint32(cap);
 
        return newValueAddr(typ, Addr(array)).(ArrayValue);
 }