Introduce upb_EncodeStatus_String and upb_DecodeStatus_String

Wrapper languages can now use these helpers to get human-friendly
error codes as opposed to manually re-mapping.

PiperOrigin-RevId: 634112262

upb/wire/decode.c

@@ -1429,5 +1429,26 @@ upb_DecodeStatus upb_DecodeLengthPrefixed(const char* buf, size_t size,
   return upb_Decode(buf, msg_len, msg, mt, extreg, options, arena);
 }
 
+const char* upb_DecodeStatus_String(upb_DecodeStatus status) {
+  switch (status) {
+    case kUpb_DecodeStatus_Ok:
+      return "Ok";
+    case kUpb_DecodeStatus_Malformed:
+      return "Wire format was corrupt";
+    case kUpb_DecodeStatus_OutOfMemory:
+      return "Arena alloc failed";
+    case kUpb_DecodeStatus_BadUtf8:
+      return "String field had bad UTF-8";
+    case kUpb_DecodeStatus_MaxDepthExceeded:
+      return "Exceeded upb_DecodeOptions_MaxDepth";
+    case kUpb_DecodeStatus_MissingRequired:
+      return "Missing required field";
+    case kUpb_DecodeStatus_UnlinkedSubMessage:
+      return "Unlinked sub-message field was present";
+    default:
+      return "Unknown decode status";
+  }
+}
+
 #undef OP_FIXPCK_LG2
 #undef OP_VARPCK_LG2

upb/wire/decode.h

@@ -143,6 +143,9 @@ UPB_API upb_DecodeStatus upb_DecodeLengthPrefixed(
     const upb_MiniTable* mt, const upb_ExtensionRegistry* extreg, int options,
     upb_Arena* arena);
 
+// Utility function for wrapper languages to get an error string from a
+// upb_DecodeStatus.
+UPB_API const char* upb_DecodeStatus_String(upb_DecodeStatus status);
 #ifdef __cplusplus
 } /* extern "C" */
 #endif

upb/wire/encode.c

@@ -668,3 +668,18 @@ upb_EncodeStatus upb_EncodeLengthPrefixed(const upb_Message* msg,
                                           size_t* size) {
   return _upb_Encode(msg, l, options, arena, buf, size, true);
 }
+
+const char* upb_EncodeStatus_String(upb_EncodeStatus status) {
+  switch (status) {
+    case kUpb_EncodeStatus_Ok:
+      return "Ok";
+    case kUpb_EncodeStatus_MissingRequired:
+      return "Missing required field";
+    case kUpb_EncodeStatus_MaxDepthExceeded:
+      return "Max depth exceeded";
+    case kUpb_EncodeStatus_OutOfMemory:
+      return "Arena alloc failed";
+    default:
+      return "Unknown encode status";
+  }
+}

upb/wire/encode.h

@@ -75,6 +75,9 @@ UPB_API upb_EncodeStatus upb_EncodeLengthPrefixed(const upb_Message* msg,
                                                   const upb_MiniTable* l,
                                                   int options, upb_Arena* arena,
                                                   char** buf, size_t* size);
+// Utility function for wrapper languages to get an error string from a
+// upb_EncodeStatus.
+UPB_API const char* upb_EncodeStatus_String(upb_EncodeStatus status);
 
 #ifdef __cplusplus
 } /* extern "C" */