Added kNuErrFileAccessDenied. Return it when OpenRW fails with an

access permission problem, so that an application can follow it with
an OpenRO call for read-only files.

nufxlib-0/Archive.c

@@ -769,6 +769,9 @@ bail:
 /*
  * Open a temp file.  If "fileName" contains six Xs ("XXXXXX"), it will
  * be treated as a mktemp-style template, and modified before use.
+ *
+ * Thought for the day: consider using Win32 SetFileAttributes() to make
+ * temp files hidden.  We will need to un-hide it before rolling it over.
  */
 static NuError
 Nu_OpenTempFile(char* fileName, FILE** pFp)
@@ -914,8 +917,11 @@ Nu_OpenRW(const char* archivePathname, const char* tmpPathname, ulong flags,
     }
 
     if (fp == nil) {
+        if (errno == EACCES)
+            err = kNuErrFileAccessDenied;
+        else
+            err = kNuErrFileOpen;
         Nu_ReportError(NU_BLOB, errno, "Unable to open '%s'", archivePathname);
-        err = kNuErrFileOpen;
         goto bail;
     }
 

nufxlib-0/MiscUtils.c

@@ -104,6 +104,8 @@ Nu_StrError(NuError err)
         return "Unable to set file date";
     case kNuErrFileSetAccess:
         return "Unable to set file access";
+    case kNuErrFileAccessDenied:
+        return "Access denied";
 
     case kNuErrNotNuFX:
         return "Input is not a NuFX archive";

nufxlib-0/NufxLib.h

@@ -84,6 +84,7 @@ typedef enum NuError {
     kNuErrReadDir       = -35,      /* error reading directory */
     kNuErrFileSetDate   = -36,      /* unable to set file date */
     kNuErrFileSetAccess = -37,      /* unable to set file access permissions */
+    kNuErrFileAccessDenied = -38,   /* equivalent to EACCES */
 
     kNuErrNotNuFX       = -40,      /* 'NuFile' missing; not a NuFX archive? */
     kNuErrBadMHVersion  = -41,      /* bad master header version */