Add AF_UNIX support on windows (#2115)

Signed-off-by: Piotr Stankiewicz <[email protected]>

Author: Piotr

httplib.h

@@ -187,6 +187,7 @@ using ssize_t = long;
 #include <io.h>
 #include <winsock2.h>
 #include <ws2tcpip.h>
+#include <afunix.h>
 
 #ifndef WSA_FLAG_NO_HANDLE_INHERIT
 #define WSA_FLAG_NO_HANDLE_INHERIT 0x80
@@ -3538,7 +3539,6 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
     hints.ai_flags = socket_flags;
   }
 
-#ifndef _WIN32
   if (hints.ai_family == AF_UNIX) {
     const auto addrlen = host.length();
     if (addrlen > sizeof(sockaddr_un::sun_path)) { return INVALID_SOCKET; }
@@ -3562,11 +3562,19 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
           sizeof(addr) - sizeof(addr.sun_path) + addrlen);
 
 #ifndef SOCK_CLOEXEC
+#ifndef _WIN32
       fcntl(sock, F_SETFD, FD_CLOEXEC);
+#endif
 #endif
 
       if (socket_options) { socket_options(sock); }
 
+#ifdef _WIN32
+      // Setting SO_REUSEADDR seems not to work well with AF_UNIX on windows, so avoid
+      // setting default_socket_options.
+      detail::set_socket_opt(sock, SOL_SOCKET, SO_REUSEADDR, 0);
+#endif
+
       bool dummy;
       if (!bind_or_connect(sock, hints, dummy)) {
         close_socket(sock);
@@ -3575,7 +3583,6 @@ socket_t create_socket(const std::string &host, const std::string &ip, int port,
     }
     return sock;
   }
-#endif
 
   auto service = std::to_string(port);
 

test/test.cc

@@ -70,7 +70,6 @@ static void read_file(const std::string &path, std::string &out) {
   fs.read(&out[0], static_cast<std::streamsize>(size));
 }
 
-#ifndef _WIN32
 class UnixSocketTest : public ::testing::Test {
 protected:
   void TearDown() override { std::remove(pathname_.c_str()); }
@@ -167,6 +166,7 @@ TEST_F(UnixSocketTest, abstract) {
 }
 #endif
 
+#ifndef _WIN32
 TEST(SocketStream, wait_writable_UNIX) {
   int fds[2];
   ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM, 0, fds));