Allow UTF-8 paths on Windows

A paths trouble appears on Windows OS when program which uses luajit is placed in a path which contains non-ASCII characters.
Usually on Linux, OS X and other posix and unix-like platforms paths are encoded as UTF-8, therefore no troubles with fopen() function.
On modern Windows versions all paths are encoded as UTF-16LE and also fopen() function on Windows always accepts ANSI-encoded paths,
therefore because a codepage mismatch, fopen() think that file is not exists.
To resolve this trouble need to convert accepted path into UTF-16 from UTF-8 and use _wfopen() which accepts UTF-16 paths.

_lua_fopen() and _lua_freopen() functions are made to allow support of UTF-8 paths
on Windows, on any other platforms there are a macros over standard fopen/freopen functions.

src/Makefile

@@ -486,7 +486,7 @@ LJCORE_O= lj_gc.o lj_err.o lj_char.o lj_bc.o lj_obj.o lj_buf.o \
 	  lj_asm.o lj_trace.o lj_gdbjit.o \
 	  lj_ctype.o lj_cdata.o lj_cconv.o lj_ccall.o lj_ccallback.o \
 	  lj_carith.o lj_clib.o lj_cparse.o \
-	  lj_lib.o lj_alloc.o lib_aux.o \
+	  lj_lib.o lj_alloc.o lib_aux.o lj_fopen.o \
 	  $(LJLIB_O) lib_init.o
 
 LJVMCORE_O= $(LJVM_O) $(LJCORE_O)

src/lib_io.c

@@ -25,6 +25,7 @@
 #include "lj_strfmt.h"
 #include "lj_ff.h"
 #include "lj_lib.h"
+#include "lj_fopen.h"
 
 /* Userdata payload for I/O file. */
 typedef struct IOFileUD {
@@ -84,7 +85,7 @@ static IOFileUD *io_file_open(lua_State *L, const char *mode)
 {
   const char *fname = strdata(lj_lib_checkstr(L, 1));
   IOFileUD *iof = io_file_new(L);
-  iof->fp = fopen(fname, mode);
+  iof->fp = _lua_fopen(fname, mode);
   if (iof->fp == NULL)
     luaL_argerror(L, 1, lj_strfmt_pushf(L, "%s: %s", fname, strerror(errno)));
   return iof;
@@ -401,7 +402,7 @@ LJLIB_CF(io_open)
   GCstr *s = lj_lib_optstr(L, 2);
   const char *mode = s ? strdata(s) : "r";
   IOFileUD *iof = io_file_new(L);
-  iof->fp = fopen(fname, mode);
+  iof->fp = _lua_fopen(fname, mode);
   return iof->fp != NULL ? 1 : luaL_fileresult(L, 0, fname);
 }
 

src/lib_package.c

@@ -16,6 +16,7 @@
 #include "lj_obj.h"
 #include "lj_err.h"
 #include "lj_lib.h"
+#include "lj_fopen.h"
 
 /* ------------------------------------------------------------------------ */
 
@@ -270,7 +271,7 @@ static int lj_cf_package_unloadlib(lua_State *L)
 
 static int readable(const char *filename)
 {
-  FILE *f = fopen(filename, "r");  /* try to open file */
+  FILE *f = _lua_fopen(filename, "r");  /* try to open file */
   if (f == NULL) return 0;  /* open failed */
   fclose(f);
   return 1;

src/lj_clib.c

@@ -17,6 +17,7 @@
 #include "lj_cdata.h"
 #include "lj_clib.h"
 #include "lj_strfmt.h"
+#include "lj_fopen.h"
 
 /* -- OS-specific functions ----------------------------------------------- */
 
@@ -94,7 +95,7 @@ static const char *clib_check_lds(lua_State *L, const char *buf)
 /* Quick and dirty solution to resolve shared library name from ld script. */
 static const char *clib_resolve_lds(lua_State *L, const char *name)
 {
-  FILE *fp = fopen(name, "r");
+  FILE *fp = _lua_fopen(name, "r");
   const char *p = NULL;
   if (fp) {
     char buf[256];

src/lj_fopen.c

@@ -0,0 +1,46 @@
+#include "lj_fopen.h"
+/*
+ * Forces to look for unicode paths on Windows
+ */
+#ifdef _WIN32
+#include <windows.h>
+
+FILE *_lua_fopen(const char *filename, const char *mode)
+{
+    int fn_len_s=strlen(filename);
+    if(fn_len_s==0) return NULL;
+    int m_len_s=strlen(mode);
+    if(m_len_s==0) return NULL;
+    wchar_t path[MAX_PATH];
+    wchar_t wmode[MAX_PATH];
+    int new_Len1 = MultiByteToWideChar(CP_UTF8, 0, filename, fn_len_s, path, fn_len_s);
+    if(new_Len1>=MAX_PATH) return NULL;
+    path[new_Len1] = L'\0';
+    int new_Len2 = MultiByteToWideChar(CP_UTF8, 0, mode, m_len_s, wmode, m_len_s);
+    if(new_Len2>=MAX_PATH) return NULL;
+    wmode[new_Len2] = L'\0';
+    FILE *f = _wfopen(path, wmode);
+    return f;
+}
+
+FILE *_lua_freopen(const char *filename, const char *mode, FILE * oldfile)
+{
+    int fn_len_s=strlen(filename);
+    if(fn_len_s==0) return NULL;
+    int m_len_s=strlen(filename);
+    if(m_len_s==0) return NULL;
+    wchar_t path[MAX_PATH];
+    wchar_t wmode[MAX_PATH];
+    int new_Len1 = MultiByteToWideChar(CP_UTF8, 0, filename, fn_len_s, path, fn_len_s);
+    if(new_Len1>=MAX_PATH) return NULL;
+    path[new_Len1] = L'\0';
+    int new_Len2 = MultiByteToWideChar(CP_UTF8, 0, mode, m_len_s, wmode, m_len_s);
+    if(new_Len2>=MAX_PATH) return NULL;
+    wmode[new_Len2] = L'\0';
+    FILE *f = _wfreopen(path, wmode, oldfile);
+    LocalFree(path);
+    LocalFree(wmode);
+    return f;
+}
+
+#endif

src/lj_fopen.h

@@ -0,0 +1,14 @@
+#ifndef LJ_FILE_OPEN_H
+#define LJ_FILE_OPEN_H
+
+#include <stdio.h>
+
+#ifdef _WIN32
+FILE *_lua_fopen(const char *filename, const char *mode);
+FILE *_lua_freopen(const char *filename, const char *mode, FILE *oldfile);
+#else
+#define _lua_fopen(file, mode) fopen(file, mode)
+#define _lua_freopen(file, mode, oldfile) freopen(file, mode, oldfile)
+#endif
+
+#endif // LJ_FILE_OPEN_H

src/lj_load.c

@@ -22,6 +22,7 @@
 #include "lj_lex.h"
 #include "lj_bcdump.h"
 #include "lj_parse.h"
+#include "lj_fopen.h"
 
 /* -- Load Lua source code and bytecode ----------------------------------- */
 
@@ -88,7 +89,7 @@ LUALIB_API int luaL_loadfilex(lua_State *L, const char *filename,
   int status;
   const char *chunkname;
   if (filename) {
-    ctx.fp = fopen(filename, "rb");
+    ctx.fp = _lua_fopen(filename, "rb");
     if (ctx.fp == NULL) {
       lua_pushfstring(L, "cannot open %s: %s", filename, strerror(errno));
       return LUA_ERRFILE;

src/lj_trace.c

@@ -30,6 +30,7 @@
 #include "lj_vm.h"
 #include "lj_vmevent.h"
 #include "lj_target.h"
+#include "lj_fopen.h"
 
 /* -- Error handling ------------------------------------------------------ */
 
@@ -109,7 +110,7 @@ static void perftools_addtrace(GCtrace *T)
   if (!fp) {
     char fname[40];
     sprintf(fname, "/tmp/perf-%d.map", getpid());
-    if (!(fp = fopen(fname, "w"))) return;
+    if (!(fp = _lua_fopen(fname, "w"))) return;
     setlinebuf(fp);
   }
   fprintf(fp, "%lx %x TRACE_%d::%s:%u\n",