Another fix for handling of file names on Windows 9X.

 src/w32.c (pMultiByteToWideChar, pWideCharToMultiByte): New
 variables: pointers through which to call the respective APIs.
 (filename_to_utf16, filename_from_utf16, filename_to_ansi)
 (filename_from_ansi, sys_link, check_windows_init_file): Call
 MultiByteToWideChar and WideCharToMultiByte through pointers.
 This is required on Windows 9X, where we dynamically load
 UNICOWS.DLL which has their non-stub implementations.
 (maybe_load_unicows_dll): Assign addresses to these 2 function
 pointers after loading UNICOWS.DLL.
 src/w32fns.c (Fx_file_dialog, Fw32_shell_execute) [!CYGWIN]: Call
 MultiByteToWideChar and WideCharToMultiByte through function
 pointers.
 src/w32.h (pMultiByteToWideChar, pWideCharToMultiByte): New
 declarations.

1 files changed, 40 insertions, 20 deletions

diff --git a/src/w32.c b/src/w32.c
index ebd1dff0b4d..11fb2a72f69 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -478,6 +478,9 @@ typedef DWORD (WINAPI *GetAdaptersInfo_Proc) (
     PIP_ADAPTER_INFO pAdapterInfo,
     PULONG pOutBufLen);
 
+int (WINAPI *pMultiByteToWideChar)(UINT,DWORD,LPCSTR,int,LPWSTR,int);
+int (WINAPI *pWideCharToMultiByte)(UINT,DWORD,LPCWSTR,int,LPSTR,int,LPCSTR,LPBOOL);
+
   /* ** A utility function ** */
 static BOOL
 is_windows_9x (void)
@@ -1543,8 +1546,8 @@ codepage_for_filenames (CPINFO *cp_info)
 int
 filename_to_utf16 (const char *fn_in, wchar_t *fn_out)
 {
-  int result = MultiByteToWideChar (CP_UTF8, MB_ERR_INVALID_CHARS, fn_in, -1,
-                                    fn_out, MAX_PATH);
+  int result = pMultiByteToWideChar (CP_UTF8, MB_ERR_INVALID_CHARS, fn_in, -1,
+                                     fn_out, MAX_PATH);
 
   if (!result)
     {
@@ -1570,8 +1573,8 @@ filename_to_utf16 (const char *fn_in, wchar_t *fn_out)
 int
 filename_from_utf16 (const wchar_t *fn_in, char *fn_out)
 {
-  int result = WideCharToMultiByte (CP_UTF8, 0, fn_in, -1,
-                                    fn_out, MAX_UTF8_PATH, NULL, NULL);
+  int result = pWideCharToMultiByte (CP_UTF8, 0, fn_in, -1,
+                                     fn_out, MAX_UTF8_PATH, NULL, NULL);
 
   if (!result)
     {
@@ -1604,8 +1607,8 @@ filename_to_ansi (const char *fn_in, char *fn_out)
       int result;
       int codepage = codepage_for_filenames (NULL);
 
-      result  = WideCharToMultiByte (codepage, 0, fn_utf16, -1,
-                                     fn_out, MAX_PATH, NULL, NULL);
+      result  = pWideCharToMultiByte (codepage, 0, fn_utf16, -1,
+                                      fn_out, MAX_PATH, NULL, NULL);
       if (!result)
         {
           DWORD err = GetLastError ();
@@ -1634,8 +1637,8 @@ filename_from_ansi (const char *fn_in, char *fn_out)
 {
   wchar_t fn_utf16[MAX_PATH];
   int codepage = codepage_for_filenames (NULL);
-  int result = MultiByteToWideChar (codepage, MB_ERR_INVALID_CHARS, fn_in, -1,
-                                    fn_utf16, MAX_PATH);
+  int result = pMultiByteToWideChar (codepage, MB_ERR_INVALID_CHARS, fn_in, -1,
+                                     fn_utf16, MAX_PATH);
 
   if (!result)
     {
@@ -4033,8 +4036,8 @@ sys_link (const char * old, const char * new)
       /* We used to pass MB_PRECOMPOSED as the 2nd arg here, but MSDN
          indicates that flag is unsupported for CP_UTF8, and OTOH says
          it is the default anyway.  */
-      wlen = MultiByteToWideChar (CP_UTF8, 0, newname, -1,
-                                  data.wid.cStreamName, MAX_PATH);
+      wlen = pMultiByteToWideChar (CP_UTF8, 0, newname, -1,
+                                   data.wid.cStreamName, MAX_PATH);
       if (wlen > 0)
         {
           LPVOID context = NULL;
@@ -8749,22 +8752,22 @@ check_windows_init_file (void)
                    "not unpacked properly.\nSee the README.W32 file in the "
                    "top-level Emacs directory for more information.",
                    init_file_name, load_path);
-          needed = MultiByteToWideChar (CP_UTF8, MB_ERR_INVALID_CHARS, buffer,
-                                        -1, NULL, 0);
+          needed = pMultiByteToWideChar (CP_UTF8, MB_ERR_INVALID_CHARS, buffer,
+                                         -1, NULL, 0);
           if (needed > 0)
             {
               wchar_t *msg_w = alloca ((needed + 1) * sizeof (wchar_t));
 
-              MultiByteToWideChar (CP_UTF8, MB_ERR_INVALID_CHARS, buffer, -1,
-                                   msg_w, needed);
-              needed = WideCharToMultiByte (CP_ACP, 0, msg_w, -1,
-                                            NULL, 0, NULL, NULL);
+              pMultiByteToWideChar (CP_UTF8, MB_ERR_INVALID_CHARS, buffer, -1,
+                                    msg_w, needed);
+              needed = pWideCharToMultiByte (CP_ACP, 0, msg_w, -1,
+                                             NULL, 0, NULL, NULL);
               if (needed > 0)
                 {
                   char *msg_a = alloca (needed + 1);
 
-                  WideCharToMultiByte (CP_ACP, 0, msg_w, -1, msg_a, needed,
-                                       NULL, NULL);
+                  pWideCharToMultiByte (CP_ACP, 0, msg_w, -1, msg_a, needed,
+                                        NULL, NULL);
                   msg = msg_a;
                 }
             }
@@ -8932,7 +8935,17 @@ maybe_load_unicows_dll (void)
     {
       HANDLE ret = LoadLibrary ("Unicows.dll");
       if (ret)
-        return ret;
+        {
+          /* These two functions are present on Windows 9X as stubs
+             that always fail.  We need the real implementations from
+             UNICOWS.DLL, so we must call these functions through
+             pointers, and assign the correct addresses to these
+             pointers at program startup (see emacs.c, which calls
+             this function early on).  */
+          pMultiByteToWideChar = GetProcAddress (ret, "MultiByteToWideChar");
+          pWideCharToMultiByte = GetProcAddress (ret, "WideCharToMultiByte");
+          return ret;
+        }
       else
         {
           int button;
@@ -8954,7 +8967,14 @@ maybe_load_unicows_dll (void)
         }
     }
   else
-    return LoadLibrary ("Gdi32.dll");
+    {
+      /* On NT family of Windows, these two functions are always
+         linked in, so we just assign their addresses to the 2
+         pointers; no need for the LoadLibrary dance.  */
+      pMultiByteToWideChar = MultiByteToWideChar;
+      pWideCharToMultiByte = WideCharToMultiByte;
+      return LoadLibrary ("Gdi32.dll");
+    }
 }
 
 /*