close.hpp

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// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef __STOUT_OS_WINDOWS_CLOSE_HPP__
#define __STOUT_OS_WINDOWS_CLOSE_HPP__

#include <stout/error.hpp>
#include <stout/nothing.hpp>
#include <stout/try.hpp>

#include <stout/os/int_fd.hpp>

#include <stout/os/windows/socket.hpp>

namespace os {

inline Try<Nothing> close(const int_fd& fd)
{
  switch (fd.type()) {
    case WindowsFD::Type::HANDLE: {
      if (!fd.is_valid()) {
        // NOTE: We return early here because
        // `CloseHandle(INVALID_HANDLE_VALUE)` will not return an error, but
        // instead (sometimes) triggers the invalid parameter handler, thus
        // throwing an exception. We'd rather return an error.
        return WindowsError(ERROR_INVALID_HANDLE);
      }

      if (::CloseHandle(fd) == FALSE) {
        return WindowsError();
      }

      return Nothing();
    }
    case WindowsFD::Type::SOCKET: {
      // NOTE: Since closing an unconnected socket is not an error in POSIX,
      // we simply ignore it here.
      if (::shutdown(fd, SD_BOTH) == SOCKET_ERROR &&
          WSAGetLastError() != WSAENOTCONN) {
        return WindowsSocketError("Failed to shutdown a socket");
      }

      if (::closesocket(fd) == SOCKET_ERROR) {
        return WindowsSocketError("Failed to close a socket");
      }

      return Nothing();
    }
  }

  UNREACHABLE();
}

} // namespace os {

#endif // __STOUT_OS_WINDOWS_CLOSE_HPP__