sdk/lib/fidl/cpp/wire/unknown_interactions.cc

// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <lib/fidl/cpp/transaction_header.h>
#include <lib/fidl/cpp/wire/internal/transport_channel.h>
#include <lib/fidl/cpp/wire/message.h>
#include <lib/fidl/cpp/wire/unknown_interactions.h>

#include <cstring>

namespace fidl::internal {

UnknownMethodReply UnknownMethodReply::MakeReplyFor(uint64_t method_ordinal,
                                                    ::fidl::MessageDynamicFlags dynamic_flags) {
  const fidl_union_tag_t kFrameworkErrTag = 3;
  const zx_status_t kUnknownMethodStatus = ZX_ERR_NOT_SUPPORTED;
  UnknownMethodReply reply{
      .body{
          .tag = kFrameworkErrTag,
          .envelope =
              {
                  .num_handles = 0,
                  .flags = FIDL_ENVELOPE_FLAGS_INLINING_MASK,
              },
      },
  };
  InitTxnHeader(&reply.header, 0, method_ordinal, dynamic_flags);

  static_assert(sizeof(reply.body.envelope.inline_value) == sizeof(kUnknownMethodStatus));
  ::std::memcpy(reply.body.envelope.inline_value, &kUnknownMethodStatus,
                sizeof(kUnknownMethodStatus));

  return reply;
}

void SendChannelUnknownMethodReply(UnknownMethodReply reply, ::fidl::Transaction *txn) {
  zx_channel_iovec_t iovecs[] = {
      {
          .buffer = &reply,
          .capacity = sizeof(reply),
      },
  };
  auto message = ::fidl::OutgoingMessage::Create_InternalMayBreak({
      .transport_vtable = &ChannelTransport::VTable,
      .iovecs = iovecs,
      .num_iovecs = std::size(iovecs),
      .handles = nullptr,
      .handle_metadata = nullptr,
      .num_handles = 0,
      .is_transactional = true,
  });
  txn->Reply(&message, {});
}

}  // namespace fidl::internal