upb: use upb_MessageValue in upb_Extension

PiperOrigin-RevId: 602785269

upb/message/BUILD

@@ -56,6 +56,7 @@ cc_library(
     srcs = [
         "internal/extension.c",
         "internal/message.c",
+        "value.h",
     ],
     hdrs = [
         "internal/accessors.h",

upb/message/copy.c

@@ -265,7 +265,7 @@ upb_Message* _upb_Message_Copy(upb_Message* dst, const upb_Message* src,
         return NULL;
       }
     } else {
-      upb_Array* msg_array = (upb_Array*)msg_ext->data.ptr;
+      upb_Array* msg_array = (upb_Array*)msg_ext->data.array_val;
       UPB_ASSERT(msg_array);
       upb_Array* cloned_array = upb_Array_DeepClone(
           msg_array, upb_MiniTableField_CType(field),
@@ -273,7 +273,7 @@ upb_Message* _upb_Message_Copy(upb_Message* dst, const upb_Message* src,
       if (!cloned_array) {
         return NULL;
       }
-      dst_ext->data.ptr = (void*)cloned_array;
+      dst_ext->data.array_val = cloned_array;
     }
   }
 

upb/message/internal/extension.h

@@ -8,9 +8,10 @@
 #ifndef UPB_MESSAGE_INTERNAL_EXTENSION_H_
 #define UPB_MESSAGE_INTERNAL_EXTENSION_H_
 
-#include "upb/base/string_view.h"
+#include <stddef.h>
+
 #include "upb/mem/arena.h"
-#include "upb/message/internal/message.h"
+#include "upb/message/value.h"
 #include "upb/mini_table/extension.h"
 
 // Must be last.
@@ -26,11 +27,7 @@
 // the most common extension type.
 typedef struct {
   const upb_MiniTableExtension* ext;
-  union {
-    upb_StringView str;
-    void* ptr;
-    char scalar_data[8];
-  } data;
+  upb_MessageValue data;
 } upb_Extension;
 
 #ifdef __cplusplus

upb/message/promote.c

@@ -106,7 +106,7 @@ upb_GetExtension_Status upb_Message_GetOrPromoteExtension(
   if (!ext) {
     return kUpb_GetExtension_OutOfMemory;
   }
-  ext->data.ptr = extension_msg;
+  ext->data.msg_val = extension_msg;
   value->msg_val = extension_msg;
   const char* delete_ptr = upb_Message_GetUnknown(msg, &len) + ofs;
   upb_Message_DeleteUnknown(msg, delete_ptr, result.len);

upb/message/promote.h

@@ -10,6 +10,7 @@
 
 #include "upb/message/array.h"
 #include "upb/message/map.h"
+#include "upb/message/value.h"
 #include "upb/wire/decode.h"
 
 // Must be last.

upb/wire/encode.c

@@ -525,7 +525,7 @@ static void encode_field(upb_encstate* e, const upb_Message* msg,
 static void encode_msgset_item(upb_encstate* e, const upb_Extension* ext) {
   size_t size;
   encode_tag(e, kUpb_MsgSet_Item, kUpb_WireType_EndGroup);
-  encode_message(e, ext->data.ptr,
+  encode_message(e, ext->data.msg_val,
                  upb_MiniTableExtension_GetSubMessage(ext->ext), &size);
   encode_varint(e, size);
   encode_tag(e, kUpb_MsgSet_Message, kUpb_WireType_Delimited);