replyErrBytes method

void replyErrBytes(ZBytes payload, { Encoding? encoding, })

Sends an error reply to this query with a ZBytes payload.

The payload is consumed by this call (ownership transferred to zenoh). Optionally specify an encoding for the payload. Error replies carry a payload + encoding ONLY -- there is no attachment parameter (zenoh-c's z_query_reply_err_options_t has no attachment field).

Throws StateError if the query has been disposed. Throws ZenohException if the reply fails.

Implementation

void replyErrBytes(ZBytes payload, {Encoding? encoding}) {
  // PRE-move early-return guard: a disposed query throws StateError here,
  // BEFORE any z_bytes_move, so the caller retains ownership of payload and
  // we must NOT mark it consumed on this path (mirrors replyBytes).
  _ensureNotDisposed();

  // Two INDEPENDENT length-carried channels (R-2), from the RAW pair (R-3a).
  final (mime, schema) = encoding != null
      ? encodingWireChannels(encoding)
      : (null, null);
  final encodingBuf = allocLengthCarriedUtf8(mime);
  final schemaBuf = allocLengthCarriedUtf8(schema);

  try {
    final rc = bindings.zd_query_reply_err(
      Pointer.fromAddress(_handle).cast(),
      payload.nativePtr.cast(),
      encodingBuf.ptr,
      encodingBuf.len,
      schemaBuf.ptr,
      schemaBuf.len,
    );

    // Mark the payload ZBytes consumed UNCONDITIONALLY: once we reach this
    // FFI call the pre-move guard above has passed, so zd_query_reply_err has
    // moved the payload into zenoh-c regardless of the return code (its
    // encoding-error path drops the already-moved bytes). Marking before the
    // rc-throw prevents a later use-after-move. The encoding is a MIME string
    // (not a caller-owned ZBytes), so it needs no Dart-side markConsumed.
    payload.markConsumed();

    if (rc != 0) {
      throw ZenohException('Failed to send error reply to query', rc);
    }
  } finally {
    if (encodingBuf.ptr != nullptr) calloc.free(encodingBuf.ptr);
    if (schemaBuf.ptr != nullptr) calloc.free(schemaBuf.ptr);
  }
}