fftools: Stop using av_fopen_utf8

Provide a header based inline reimplementation of it.

Using av_fopen_utf8 doesn't work outside of the libraries when built
with MSVC as shared libraries (in the default configuration, where
each DLL gets a separate statically linked CRT).

Signed-off-by: Martin Storsjö <martin@martin.st>

fftools/ffmpeg_opt.c

@@ -28,6 +28,7 @@
 #endif
 
 #include "ffmpeg.h"
+#include "fopen_utf8.h"
 #include "cmdutils.h"
 #include "opt_common.h"
 
@@ -1882,7 +1883,7 @@ static OutputStream *new_video_stream(OptionsContext *o, AVFormatContext *oc, in
                     video_enc->stats_in = logbuffer;
                 }
                 if (video_enc->flags & AV_CODEC_FLAG_PASS1) {
-                    f = av_fopen_utf8(logfilename, "wb");
+                    f = fopen_utf8(logfilename, "wb");
                     if (!f) {
                         av_log(NULL, AV_LOG_FATAL,
                                "Cannot write log file '%s' for pass-1 encoding: %s\n",

fftools/fopen_utf8.h

@@ -0,0 +1,71 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef FFTOOLS_FOPEN_UTF8_H
+#define FFTOOLS_FOPEN_UTF8_H
+
+#include <stdio.h>
+
+/* The fopen_utf8 function here is essentially equivalent to av_fopen_utf8,
+ * except that it doesn't set O_CLOEXEC, and that it isn't exported
+ * from a different library. (On Windows, each DLL might use a different
+ * CRT, and FILE* handles can't be shared across them.) */
+
+#ifdef _WIN32
+#include "libavutil/wchar_filename.h"
+
+static inline FILE *fopen_utf8(const char *path_utf8, const char *mode)
+{
+    wchar_t *path_w, *mode_w;
+    FILE *f;
+
+    /* convert UTF-8 to wide chars */
+    if (utf8towchar(path_utf8, &path_w)) /* This sets errno on error. */
+        return NULL;
+    if (!path_w)
+        goto fallback;
+
+    if (utf8towchar(mode, &mode_w))
+        return NULL;
+    if (!mode_w) {
+        /* If failing to interpret the mode string as utf8, it is an invalid
+         * parameter. */
+        av_freep(&path_w);
+        errno = EINVAL;
+        return NULL;
+    }
+
+    f = _wfopen(path_w, mode_w);
+    av_freep(&path_w);
+    av_freep(&mode_w);
+
+    return f;
+fallback:
+    /* path may be in CP_ACP */
+    return fopen(path_utf8, mode);
+}
+
+#else
+
+static inline FILE *fopen_utf8(const char *path, const char *mode)
+{
+    return fopen(path, mode);
+}
+#endif
+
+#endif /* FFTOOLS_FOPEN_UTF8_H */