Re: directory caching anomalies in win32

[Aaron Shatters]

>> Date: Mon, 23 Apr 2007 07:45:03 -0700 (PDT)
>> From: Aaron Shatters <address@hidden>
>> Cc: address@hidden
>> 
>> >> Date: Fri, 20 Apr 2007 13:53:31 -0700 (PDT)
>> >> From: Aaron Shatters <address@hidden>
>> >> 
>> >> What was the reason for rehashing the directory contents for windows if 
>> >> the file was not found in the directory cache and the directory has been 
>> >> modified... but not on any other platforms?
>> >
>> >Could you please point to the code fragment(s) where you see this
>> >difference?
>> 
>> In dir.c -->
>> 
>>   if (dir->dirstream == 0)
>>   {
>> #ifdef WINDOWS32
>>     /*
>>      * Check to see if directory has changed since last read. FAT
>>      * filesystems force a rehash always as mtime does not change
>>      * on directories (ugh!).
>>      */
>>      if (dir->path_key)
>>      {
>>        if ((dir->fs_flags & FS_FAT) != 0)
>>        {
>>          dir->mtime = time ((time_t *) 0);
>>          rehash = 1;
>>        }
>>        else if (stat(dir->path_key, &st) == 0 && st.st_mtime > dir->mtime)
>>        {
>>          /* reset date stamp to show most recent re-process.  */
>>          dir->mtime = st.st_mtime;
>>          rehash = 1;
>>        }
>>        /* If it has been already read in, all done.  */
>>        if (!rehash)
>>          return 0;
>>        /* make sure directory can still be opened; if not return.  */
>>        dir->dirstream = opendir(dir->path_key);
>>        if (!dir->dirstream)
>>          return 0;
>>      }
>>      else
>> #endif
>
vThis fragment handles the problem that inode emulation on Windows
>filesystems are not reliable.  It replaces the inode check by
>`stat'ing the directory whose normalized file name is stored in
>dir->path_key.
>
>Does this code really get run when you invoke $wildcard, and why?

Yes, it does.  "func_wildcard" calls "string_glob".  "string_glob" calls 
"file_exists_p".  "file_exists_p" calls "dir_file_exists_p".  
"dir_file_exists_p" calls "dir_contents_file_exists_p"... and there you have 
it.  The code above gets run if the $(wildcard...) argument doesn't contain any 
wildcard characters (for example: file.o), and the file did not exist when the 
directory contents was cached.

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