protobuf/ruby/ext/google/protobuf_c/shared_message.c

// Protocol Buffers - Google's data interchange format
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// -----------------------------------------------------------------------------
// Ruby Message functions. Strictly free of dependencies on
// Ruby interpreter internals.

#include "shared_message.h"

// Support function for Message_Hash. Returns a hash value for the given
// message.
uint64_t shared_Message_Hash(const upb_Message* msg, const upb_MessageDef* m,
                             uint64_t seed, upb_Status* status) {
  upb_Arena* arena = upb_Arena_New();
  char* data;
  size_t size;

  // Hash a deterministically serialized payloads with no unknown fields.
  upb_EncodeStatus encode_status = upb_Encode(
      msg, upb_MessageDef_MiniTable(m),
      kUpb_EncodeOption_SkipUnknown | kUpb_EncodeOption_Deterministic, arena,
      &data, &size);

  if (encode_status == kUpb_EncodeStatus_Ok) {
    uint64_t ret = _upb_Hash(data, size, seed);
    upb_Arena_Free(arena);
    return ret;
  } else {
    upb_Arena_Free(arena);
    upb_Status_SetErrorMessage(status, "Error calculating hash");
  }
}

// Support function for Message_Equal
bool shared_Message_Equal(const upb_Message* m1, const upb_Message* m2,
                          const upb_MessageDef* m, upb_Status* status) {
  if (m1 == m2) return true;

  size_t size1, size2;
  int encode_opts =
      kUpb_EncodeOption_SkipUnknown | kUpb_EncodeOption_Deterministic;
  upb_Arena* arena_tmp = upb_Arena_New();
  const upb_MiniTable* layout = upb_MessageDef_MiniTable(m);

  // Compare deterministically serialized payloads with no unknown fields.
  char* data1;
  char* data2;
  upb_EncodeStatus status1 =
      upb_Encode(m1, layout, encode_opts, arena_tmp, &data1, &size1);
  upb_EncodeStatus status2 =
      upb_Encode(m2, layout, encode_opts, arena_tmp, &data2, &size2);

  if (status1 == kUpb_EncodeStatus_Ok && status2 == kUpb_EncodeStatus_Ok) {
    bool ret = (size1 == size2) && (memcmp(data1, data2, size1) == 0);
    upb_Arena_Free(arena_tmp);
    return ret;
  } else {
    upb_Arena_Free(arena_tmp);
    upb_Status_SetErrorMessage(status, "Error comparing messages");
  }
}