Add missing files

include/tao/pq/poll.hpp

@@ -0,0 +1,29 @@
+// Copyright (c) 2023 Daniel Frey and Dr. Colin Hirsch
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef TAO_PQ_POLL_HPP
+#define TAO_PQ_POLL_HPP
+
+namespace tao::pq::poll
+{
+   enum class status
+   {
+      timeout,
+      readable,
+      writable,
+      again
+   };
+
+   using callback = status( const int socket, const bool wait_for_write, const int timeout );
+
+   namespace internal
+   {
+      callback default_poll;
+      // status default_poll( const int socket, const bool wait_for_write, const int timeout );
+
+   }  // namespace internal
+
+}  // namespace tao::pq::poll
+
+#endif

src/lib/pq/poll.cpp

@@ -0,0 +1,110 @@
+// Copyright (c) 2023 Daniel Frey and Dr. Colin Hirsch
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
+
+#include <tao/pq/poll.hpp>
+
+#include <cctype>
+#include <cerrno>
+#include <cstring>
+#include <string>
+
+#if defined( _WIN32 )
+#include <winsock2.h>
+#else
+#include <poll.h>
+#endif
+
+#include <tao/pq/exception.hpp>
+#include <tao/pq/internal/printf.hpp>
+#include <tao/pq/internal/unreachable.hpp>
+
+namespace tao::pq::poll::internal
+{
+   // LCOV_EXCL_START
+   [[nodiscard, maybe_unused]] auto errno_result_to_string( const int e, char* buffer, int result ) -> std::string
+   {
+      if( result == 0 ) {
+         return buffer;
+      }
+      return pq::internal::printf( "unknown error code %d", e );
+   }
+
+   [[nodiscard, maybe_unused]] auto errno_result_to_string( const int /*unused*/, char* /*unused*/, char* result ) -> std::string
+   {
+      return result;
+   }
+
+   [[nodiscard]] auto errno_to_string( const int e ) -> std::string
+   {
+      char buffer[ 256 ];
+#if defined( _WIN32 )
+#ifdef _MSC_VER
+      return errno_result_to_string( e, buffer, strerror_s( buffer, e ) );
+#else
+      return errno_result_to_string( e, buffer, strerror_s( buffer, sizeof( buffer ), e ) );
+#endif
+#else
+      return errno_result_to_string( e, buffer, strerror_r( e, buffer, sizeof( buffer ) ) );
+#endif
+   }
+   // LCOV_EXCL_STOP
+
+   status default_poll( const int socket, const bool wait_for_write, const int timeout )
+   {
+#if defined( _WIN32 )
+
+      const short events = POLLIN | ( wait_for_write ? POLLOUT : 0 );
+      WSAPOLLFD pfd = { static_cast< SOCKET >( socket ), events, 0 };
+      const auto result = WSAPoll( &pfd, 1, timeout );
+      switch( result ) {
+         case 0:
+            return status::timeout;
+
+         case 1:
+            if( ( pfd.revents & events ) == 0 ) {
+               throw network_error( pq::internal::printf( "WSAPoll() failed, events %hd, revents %hd", events, pfd.revents ) );
+            }
+            return ( ( pfd.revents & POLLIN ) != 0 ) ? status::readable : status::writable;
+
+         case SOCKET_ERROR:
+            const int e = WSAGetLastError();
+            throw network_error( "WSAPoll() failed: " + internal::errno_to_string( e ) );
+
+         default:
+            TAO_PQ_UNREACHABLE;
+      }
+
+#else
+
+      const short events = POLLIN | ( wait_for_write ? POLLOUT : 0 );
+      pollfd pfd = { socket, events, 0 };
+      errno = 0;
+      const auto result = ::poll( &pfd, 1, timeout );
+      switch( result ) {
+         case 0:
+            return status::timeout;
+
+         case 1:
+            if( ( pfd.revents & events ) == 0 ) {
+               throw network_error( pq::internal::printf( "poll() failed, events %hd, revents %hd", events, pfd.revents ) );  // LCOV_EXCL_LINE
+            }
+            return ( ( pfd.revents & POLLIN ) != 0 ) ? status::readable : status::writable;
+
+            // LCOV_EXCL_START
+         case -1: {
+            const int e = errno;
+            if( ( e != EINTR ) && ( e != EAGAIN ) ) {
+               throw network_error( "poll() failed: " + internal::errno_to_string( e ) );
+            }
+            return status::again;
+         }
+
+         default:
+            TAO_PQ_UNREACHABLE;
+      }
+         // LCOV_EXCL_STOP
+#endif
+   }
+
+}  // namespace tao::pq::poll::internal