path, win32: redo user configfile path handling

Remove the ifdef hell from mp_find_user_config_file(). Move the win32
specific code (for MinGW and Cygwin) to path-win.c. The behavior should
be about the same, but I can't be sure due to lack of testing and
because the old path.c code was hard to follow. (I expect those who care
about windows will fix things, should issues pop up - sorry.)

One difference is that the new code will always force MPV_HOME. It looks
like the old code preferred the mpv config dir in the exe dir if it
exists.

Also, make sure MP_PATH_MAX has enough space, even if the equivalent
wchar_t string is not 0-terminated with PATH_MAX (because apparently the
winapi doesn't require this). (Actually, maybe we should just kill all
uses of PATH_MAX/MP_PATH_MAX.)

Makefile

@@ -54,6 +54,7 @@ SOURCES-$(MPG123)               += audio/decode/ad_mpg123.c
 
 SOURCES-$(NEED_GETTIMEOFDAY)    += osdep/gettimeofday.c
 SOURCES-$(NEED_GLOB)            += osdep/glob-win.c
+SOURCES-$(WIN32)                += osdep/path-win.c
 
 SOURCES-$(PRIORITY)             += osdep/priority.c
 SOURCES-$(PVR)                  += stream/stream_pvr.c

mpvcore/path.c

@@ -37,14 +37,7 @@
 #include "mpvcore/path.h"
 #include "talloc.h"
 #include "osdep/io.h"
-
-#if defined(__MINGW32__)
-#include <windows.h>
-#include <shlobj.h>
-#elif defined(__CYGWIN__)
-#include <windows.h>
-#include <sys/cygwin.h>
-#endif
+#include "osdep/path.h"
 
 #ifdef CONFIG_COCOA
 #include "osdep/macosx_bundle.h"
@@ -77,75 +70,27 @@ char *mp_find_config_file(const char *filename)
 
 char *mp_find_user_config_file(const char *filename)
 {
-    char *homedir = NULL, *buff = NULL;
-    char *homepath = NULL;
-#ifdef __MINGW32__
-    char *config_dir = "mpv";
-    char buf[MAX_PATH];
+    char *homedir = getenv("MPV_HOME");
+    char *configdir = NULL;
+    char *result = NULL;
 
-    if (homepath == NULL) {
-        if (SHGetFolderPathA(NULL, CSIDL_LOCAL_APPDATA|CSIDL_FLAG_CREATE, NULL,
-            SHGFP_TYPE_CURRENT, buf) == S_OK) {
-
-            homepath = buf;
-        }
-    }
-#else
-    char *config_dir = ".mpv";
-
-    if (homepath == NULL) {
-        homepath = getenv("HOME");
-    }
+    if (!homedir) {
+#ifdef _WIN32
+        result = mp_get_win_config_path(filename);
 #endif
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-    char *temp = NULL;
-    char exedir[260];
-    /* Hack to get fonts etc. loaded outside of Cygwin environment. */
-    int i, imax = 0;
-    int len = (int)GetModuleFileNameA(NULL, exedir, 260);
-
-    for (i = 0; i < len; i++) {
-        if (exedir[i] == '\\') {
-            exedir[i] = '/';
-            imax = i;
-        }
+        homedir = getenv("HOME");
+        configdir = ".mpv";
     }
 
-    exedir[imax] = '\0';
-
-    if (filename) {
-        temp = mp_path_join(NULL, bstr0(exedir), bstr0(filename));
-    }
-
-    if (temp && mp_path_exists(temp) && !mp_path_isdir(temp)) {
-        homedir = exedir;
-        config_dir = "";
-    }
-    else
-#endif
-    if ((homedir = getenv("MPV_HOME")) != NULL) {
-        config_dir = "";
-    } else if ((homedir = homepath) == NULL) {
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-        homedir = exedir;
-#else
-        return NULL;
-#endif
-    }
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-    talloc_free(temp);
-#endif
-
-    if (filename) {
-        char * temp = mp_path_join(NULL, bstr0(homedir), bstr0(config_dir));
-        buff = mp_path_join(NULL, bstr0(temp), bstr0(filename));
+    if (!result && homedir) {
+        char *temp = mp_path_join(NULL, bstr0(homedir), bstr0(configdir));
+        result = mp_path_join(NULL, bstr0(temp), bstr0(filename));
         talloc_free(temp);
-    } else {
-        buff = mp_path_join(NULL, bstr0(homedir), bstr0(config_dir));
     }
 
-    mp_msg(MSGT_GLOBAL, MSGL_V, "get_path('%s') -> '%s'\n", filename, buff);
-    return buff;
+    mp_msg(MSGT_GLOBAL, MSGL_V, "mp_find_user_config_file('%s') -> '%s'\n",
+           filename ? filename : "(NULL)", result ? result : "(NULL)");
+    return result;
 }
 
 char *mp_find_global_config_file(const char *filename)

osdep/io.h

@@ -43,9 +43,11 @@ char *mp_to_utf8(void *talloc_ctx, const wchar_t *s);
 // applies to unicode paths encoded with wchar_t (2 bytes on Windows). The UTF-8
 // version could end up bigger in memory. In the worst case each wchar_t is
 // encoded to 3 bytes in UTF-8, so in the worst case we have:
-//      wcslen(wpath) <= strlen(utf8path) * 3
+//      wcslen(wpath) * 3 <= strlen(utf8path)
 // Thus we need MP_PATH_MAX as the UTF-8/char version of PATH_MAX.
-#define MP_PATH_MAX (FILENAME_MAX * 3)
+// Also make sure there's free space for the terminating \0.
+// (For codepoints encoded as UTF-16 surrogate pairs, UTF-8 has the same length.)
+#define MP_PATH_MAX (FILENAME_MAX * 3 + 1)
 
 void mp_get_converted_argv(int *argc, char ***argv);
 

osdep/path-win.c

@@ -0,0 +1,74 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mpv 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <windows.h>
+#include <shlobj.h>
+
+#include "osdep/path.h"
+#include "osdep/io.h"
+#include "mpvcore/path.h"
+
+// Warning: do not use PATH_MAX. Cygwin messed it up.
+
+static void get_exe_dir(wchar_t path[MAX_PATH + 1])
+{
+    int len = (int)GetModuleFileNameW(NULL, path, MAX_PATH);
+    int imax = 0;
+    for (int i = 0; i < len; i++) {
+        if (path[i] == '\\') {
+            path[i] = '/';
+            imax = i;
+        }
+    }
+
+    path[imax] = '\0';
+}
+
+char *mp_get_win_config_path(const char *filename)
+{
+    wchar_t w_appdir[MAX_PATH + 1] = {0};
+    wchar_t w_exedir[MAX_PATH + 1] = {0};
+    char *res = NULL;
+    void *tmp = talloc_new(NULL);
+
+#ifndef __CYGWIN__
+    if (SHGetFolderPathW(NULL, CSIDL_LOCAL_APPDATA|CSIDL_FLAG_CREATE, NULL,
+        SHGFP_TYPE_CURRENT, w_appdir) != S_OK)
+        w_appdir[0] = '\0';
+#endif
+
+    get_exe_dir(w_exedir);
+
+    if (filename && filename[0] && w_exedir[0]) {
+        char *dir = mp_to_utf8(tmp, w_exedir);
+        char *temp = mp_path_join(tmp, bstr0(dir), bstr0("mpv"));
+        res = mp_path_join(NULL, bstr0(temp), bstr0(filename));
+        if (!mp_path_exists(res) || mp_path_isdir(res)) {
+            talloc_free(res);
+            res = NULL;
+        }
+    }
+
+    if (!res && w_appdir[0]) {
+        char *dir = mp_to_utf8(tmp, w_appdir);
+        char *temp = mp_path_join(tmp, bstr0(dir), bstr0("mpv"));
+        res = mp_path_join(NULL, bstr0(temp), bstr0(filename));
+    }
+
+    talloc_free(tmp);
+    return res;
+}

osdep/path.h

@@ -0,0 +1,8 @@
+#ifndef OSDEP_PATH_H
+#define OSDEP_PATH_H
+
+#ifdef _WIN32
+char *mp_get_win_config_path(const char *filename);
+#endif
+
+#endif