From: Daniel Berger <djberg96@...>
Date: 2006-02-08T15:23:23+09:00
Subject: Re: Help: File.file?, ftype fails oddly

Chris wrote:
> Hello all,
>
> I've been working on a class+script to crawl through my directories and
> thought I had it working just right, when it crashed some 13 minutes into
> running.  I included the stack at the bottom, in case it gives a better
> hint to anyone here.
>
> The code where it fails is this method - the if checks fail to see that
> filename is a file, and even errors out on the else's File.ftype(filename)
> call:
>
> def get_dir_info_recursive change_into_dir, write_to_file, put_in_container
> Dir.chdir( change_into_dir )
> Dir.foreach(".") {|filename|
>   if File.directory?(filename) then
>     # write_to_file.puts stuff
>     # .. recursively call this method
>   elsif File.file?(filename) then
>     # write_to_file.puts stuff
>     # .. simple gather info and add to collection
>   else
>     puts "ERROR: TYPE=#{File.ftype(filename)} for #{filename} in
> #{put_in_container.path}"
>   end
> }
> Dir.chdir('..')
> end
>
>
> My problem solving skills came up with a few alternatives:
>
> 1. Maybe the filename/directory path is too long.  After all the path +
> filename end up being right about 255 characters long.
>     NOPE: Tried starting the loop right in the directory where the file
> errors out, even at earlier directories, the error doesn't happen -
> the file is correctly identified as a file!

YEP.  You're hitting the MAX_PATH character limit.  Try the following
sample code to see what I mean:

#initial = "\\\\\?\\C:\\really_long_test_path_to_be_deleted"
initial = "C:\\really_long_test_path_to_be_deleted"
Dir.mkdir(initial)
Dir.chdir(initial)

1.upto(40){ |n|
   dir = "this_is_long_dir_number_#{n}"
   file = "_some_really_long_file_#{n}.bogus"

   File.open(file, "w+"){} # touch
   puts "Created file: #{file}"

   Dir.mkdir(dir)
   puts "Created dir: #{dir}"

   Dir.chdir(dir)
   puts "Changed into dir: #{dir}"

   puts "Current dir length: " + Dir.pwd.length.to_s
   puts
}

And here's the output:

C:\eclipse\workspace\ruby-foo>ruby deepdir.rb
Created file: _some_really_long_file_1.bogus
Created dir: this_is_long_dir_number_1
Changed into dir: this_is_long_dir_number_1
Current dir length: 68

Created file: _some_really_long_file_2.bogus
Created dir: this_is_long_dir_number_2
Changed into dir: this_is_long_dir_number_2
Current dir length: 94

Created file: _some_really_long_file_3.bogus
Created dir: this_is_long_dir_number_3
Changed into dir: this_is_long_dir_number_3
Current dir length: 120

Created file: _some_really_long_file_4.bogus
Created dir: this_is_long_dir_number_4
Changed into dir: this_is_long_dir_number_4
Current dir length: 146

Created file: _some_really_long_file_5.bogus
Created dir: this_is_long_dir_number_5
Changed into dir: this_is_long_dir_number_5
Current dir length: 172

Created file: _some_really_long_file_6.bogus
Created dir: this_is_long_dir_number_6
Changed into dir: this_is_long_dir_number_6
Current dir length: 198

Created file: _some_really_long_file_7.bogus
Created dir: this_is_long_dir_number_7
Changed into dir: this_is_long_dir_number_7
Current dir length: 224

Created file: _some_really_long_file_8.bogus
deepdir.rb:14:in `mkdir': No such file or directory -
this_is_long_dir_number_8 (Errno::ENOENT)
        from deepdir.rb:14
        from deepdir.rb:7:in `upto'
        from deepdir.rb:7

Note that even adding the leading "\\?\" to the directory doesn't seem
to help (though it should).

This isn't the best error message, but that could be Microsoft's fault
- I haven't checked to see what error is returned for this case using C
and GetLastError().

Regards,

Dan