Update compat extension APIs to something that does not assume contiguous storage

PiperOrigin-RevId: 696346042

csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs

@@ -1,17 +0,0 @@
-#region Copyright notice and license
-// Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
-#endregion
-
-namespace Google.Protobuf.Reflection;
-
-internal sealed partial class FeatureSetDescriptor
-{
-    // Canonical serialized form of the edition defaults, generated by embed_edition_defaults.
-    private const string DefaultsBase64 =
-        "ChMYhAciACoMCAEQAhgCIAMoATACChMY5wciACoMCAIQARgBIAIoATABChMY6AciDAgBEAEYASACKAEwASoAIOYHKOgH";
-}

upb/message/compat.c

@@ -17,13 +17,19 @@
 // Must be last.
 #include "upb/port/def.inc"
 
-const upb_MiniTableExtension* upb_Message_ExtensionByIndex(
-    const upb_Message* msg, size_t index) {
+bool upb_Message_NextExtension(const upb_Message* msg,
+                               const upb_MiniTableExtension** result,
+                               uintptr_t* iter) {
   size_t count;
   const upb_Extension* ext = UPB_PRIVATE(_upb_Message_Getexts)(msg, &count);
-
-  UPB_ASSERT(index < count);
-  return ext[index].ext;
+  size_t i = *iter;
+  if (i >= count) {
+    return false;
+    *result = NULL;
+  }
+  *result = ext[i].ext;
+  *iter = i + 1;
+  return true;
 }
 
 const upb_MiniTableExtension* upb_Message_FindExtensionByNumber(

upb/message/compat.h

@@ -25,9 +25,11 @@
 extern "C" {
 #endif
 
-const upb_MiniTableExtension* upb_Message_ExtensionByIndex(
-    const upb_Message* msg, size_t index);
+#define kUpb_Message_ExtensionBegin 0;
 
+bool upb_Message_NextExtension(const upb_Message* msg,
+                               const upb_MiniTableExtension** result,
+                               uintptr_t* iter);
 // Returns the minitable with the given field number, or NULL on failure.
 const upb_MiniTableExtension* upb_Message_FindExtensionByNumber(
     const upb_Message* msg, uint32_t field_number);