mingw-w64: Add basic mingw-w64 support

Copied the compat stuff from libmicrodns
a 6th grader could probably do better, this is some copying from stack overflow quality code.
Signed-off-by: Christopher Degawa <ccom@randomderp.com>

compat/poll.c

+/**
+ * Copyright © 2014-2015 VideoLabs SAS
+ *
+ * Author: Jonathan Calmels <jbjcalmels@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#ifndef HAVE_POLL
+#include <winsock2.h>
+static int poll(struct pollfd *fds, unsigned nfds, int timeout) {
+    DWORD to = (timeout >= 0) ? (DWORD)timeout : INFINITE;
+
+    if (nfds == 0) { /* WSAWaitForMultipleEvents() does not allow zero events */
+        if (SleepEx(to, TRUE)) {
+            errno = EINTR;
+            return -1;
+        }
+        return 0;
+    }
+
+    WSAEVENT *evts = malloc(nfds * sizeof(WSAEVENT));
+    if (evts == NULL) return -1; /* ENOMEM */
+
+    DWORD ret = WSA_WAIT_FAILED;
+    for (unsigned i = 0; i < nfds; i++) {
+        SOCKET fd = fds[i].fd;
+        long mask = FD_CLOSE;
+        fd_set rdset, wrset, exset;
+
+        FD_ZERO(&rdset);
+        FD_ZERO(&wrset);
+        FD_ZERO(&exset);
+        FD_SET(fd, &exset);
+
+        if (fds[i].events & POLLRDNORM) {
+            mask |= FD_READ | FD_ACCEPT;
+            FD_SET(fd, &rdset);
+        }
+        if (fds[i].events & POLLWRNORM) {
+            mask |= FD_WRITE | FD_CONNECT;
+            FD_SET(fd, &wrset);
+        }
+        if (fds[i].events & POLLPRI) mask |= FD_OOB;
+
+        fds[i].revents = 0;
+
+        evts[i] = WSACreateEvent();
+        if (evts[i] == WSA_INVALID_EVENT) {
+            while (i > 0) WSACloseEvent(evts[--i]);
+            free(evts);
+            errno = ENOMEM;
+            return -1;
+        }
+
+        if (WSAEventSelect(fds[i].fd, evts[i], mask) &&
+            WSAGetLastError() == WSAENOTSOCK)
+            fds[i].revents |= POLLNVAL;
+
+        struct timeval tv = {0, 0};
+        /* By its horrible design, WSAEnumNetworkEvents() only enumerates
+         * events that were not already signaled (i.e. it is edge-triggered).
+         * WSAPoll() would be better in this respect, but worse in others.
+         * So use WSAEnumNetworkEvents() after manually checking for pending
+         * events. */
+        if (select(0, &rdset, &wrset, &exset, &tv) > 0) {
+            if (FD_ISSET(fd, &rdset))
+                fds[i].revents |= fds[i].events & POLLRDNORM;
+            if (FD_ISSET(fd, &wrset))
+                fds[i].revents |= fds[i].events & POLLWRNORM;
+            if (FD_ISSET(fd, &exset))
+                /* To add pain to injury, POLLERR and POLLPRI cannot be
+                 * distinguished here. */
+                fds[i].revents |= POLLERR | (fds[i].events & POLLPRI);
+        }
+
+        if (fds[i].revents != 0 && ret == WSA_WAIT_FAILED)
+            ret = WSA_WAIT_EVENT_0 + i;
+    }
+
+    if (ret == WSA_WAIT_FAILED)
+        ret = WSAWaitForMultipleEvents(nfds, evts, FALSE, to, TRUE);
+
+    unsigned count = 0;
+    for (unsigned i = 0; i < nfds; i++) {
+        WSANETWORKEVENTS ne;
+
+        if (WSAEnumNetworkEvents(fds[i].fd, evts[i], &ne))
+            memset(&ne, 0, sizeof(ne));
+        WSAEventSelect(fds[i].fd, evts[i], 0);
+        WSACloseEvent(evts[i]);
+
+        if (ne.lNetworkEvents & FD_CONNECT) {
+            fds[i].revents |= POLLWRNORM;
+            if (ne.iErrorCode[FD_CONNECT_BIT] != 0) fds[i].revents |= POLLERR;
+        }
+        if (ne.lNetworkEvents & FD_CLOSE) {
+            fds[i].revents |= (fds[i].events & POLLRDNORM) | POLLHUP;
+            if (ne.iErrorCode[FD_CLOSE_BIT] != 0) fds[i].revents |= POLLERR;
+        }
+        if (ne.lNetworkEvents & FD_ACCEPT) {
+            fds[i].revents |= POLLRDNORM;
+            if (ne.iErrorCode[FD_ACCEPT_BIT] != 0) fds[i].revents |= POLLERR;
+        }
+        if (ne.lNetworkEvents & FD_OOB) {
+            fds[i].revents |= POLLPRI;
+            if (ne.iErrorCode[FD_OOB_BIT] != 0) fds[i].revents |= POLLERR;
+        }
+        if (ne.lNetworkEvents & FD_READ) {
+            fds[i].revents |= POLLRDNORM;
+            if (ne.iErrorCode[FD_READ_BIT] != 0) fds[i].revents |= POLLERR;
+        }
+        if (ne.lNetworkEvents & FD_WRITE) {
+            fds[i].revents |= POLLWRNORM;
+            if (ne.iErrorCode[FD_WRITE_BIT] != 0) fds[i].revents |= POLLERR;
+        }
+        count += fds[i].revents != 0;
+    }
+
+    free(evts);
+
+    if (count == 0 && ret == WSA_WAIT_IO_COMPLETION) {
+        errno = EINTR;
+        return -1;
+    }
+    return count;
+}
+
+#endif

libndi.c

@@ -25,9 +25,19 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 #include <time.h>
 
 #include <sys/types.h>
+#ifdef _WIN32
+#include <ws2tcpip.h>
+#include <winsock2.h>
+#else
 #include <sys/socket.h>
 #include <netdb.h>
+#endif
+
+#ifdef HAVE_POLL
 #include <poll.h>
+#else
+#include "compat/poll.c"
+#endif
 
 #include <libavutil/common.h>
 #include <libavutil/frame.h>
@@ -392,7 +402,7 @@ static int receive_ndi_packet(ndi_ctx *ndi_ctx)
     uint8_t tmp[5000];
 
     /* TODO: Zero copy */
-    int len = recv(ndi_ctx->socket_fd, tmp, 5000, 0);
+    int len = recv(ndi_ctx->socket_fd, (void *)tmp, 5000, 0);
     if(len < 0)
         printf("bad \n");
 
@@ -417,7 +427,7 @@ static int request_ndi_data(ndi_ctx *ndi_ctx)
     for(int i = 0; i < 4; i++) {
         ndi_message *ndi_request = &ndi_ctx->ndi_request[i];
         // XXX: Check failure
-        send(ndi_ctx->socket_fd, ndi_request->buf, ndi_request->len, 0);
+        send(ndi_ctx->socket_fd, (void *)ndi_request->buf, ndi_request->len, 0);
         free(ndi_request->buf);
         ndi_request->buf = NULL;
         ndi_ctx->pending_requests--;
@@ -500,6 +510,26 @@ int libndi_setup(ndi_ctx *ndi_ctx, ndi_opts *ndi_opts)
     return 0;
 }
 
+#ifdef _WIN32
+static int system_InitWSA(int hi, int lo) {
+    WSADATA data;
+
+    if (WSAStartup(MAKEWORD(hi, lo), &data) == 0) {
+        if (LOBYTE(data.wVersion) == 2 && HIBYTE(data.wVersion) == 2) return 0;
+        /* Winsock DLL is not usable */
+        WSACleanup();
+    }
+    return -1;
+}
+
+static void system_Init(void) {
+    if (system_InitWSA(2, 2) && system_InitWSA(1, 1))
+        fputs("Error: cannot initialize Winsocks\n", stderr);
+}
+#else
+static void system_Init(void) { return; }
+#endif
+
 void libndi_receive_data(ndi_ctx *ndi_ctx, ndi_data_callback callback)
 {
     ndi_ctx->callback = callback;
@@ -511,6 +541,8 @@ void libndi_receive_data(ndi_ctx *ndi_ctx, ndi_data_callback callback)
     hints.ai_family = AF_UNSPEC;
     hints.ai_socktype = SOCK_STREAM;
 
+    system_Init();
+
     if ((ret = getaddrinfo(ndi_ctx->ip, ndi_ctx->port, &hints, &res)) != 0) {
         fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ret));
         goto end;

meson.build

@@ -6,6 +6,8 @@ project('libndi', 'c',
                       'b_ndebug=if-release'],
   meson_version: '>= 0.47.0')
 
+cc = meson.get_compiler('c')
+
 # API/ABI version (soversion) for the library
 ndi_soname_version       = '0.0.1'
 
@@ -17,6 +19,30 @@ add_project_arguments('-D_POSIX_C_SOURCE=200809L', language : 'c')
 
 libavutil_dep = dependency('libavutil', required: true)
 
+
+poll_src = '''
+#include <stddef.h>
+#ifdef _WIN32
+#include <winsock2.h>
+#include <windows.h>
+# if _WIN32_WINNT < 0x600
+#  error Needs vista+
+# endif
+# if defined(_MSC_VER)
+#   error
+# endif
+#else
+#include <poll.h>
+#endif
+int main() {
+  poll(NULL, 0, 0);
+}
+'''
+
+if cc.links(poll_src)
+    add_project_arguments('-DHAVE_POLL=1', language: 'c')
+endif
+
 # mDNS discovery specifics
 ndi_discovery_sources = []
 ndi_discovery_deps = []

ndi.c

@@ -25,9 +25,14 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 #include <unistd.h>
 
 #include <sys/types.h>
+#ifdef _WIN32
+#include <wspiapi.h>
+#define sleep(x) Sleep((x) * 1000)
+#else
+#include <poll.h>
 #include <sys/socket.h>
 #include <netdb.h>
-#include <poll.h>
+#endif
 
 #include <libavutil/common.h>
 #include <libavutil/frame.h>