From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-10-14T00:11:54+09:00
Subject: Re: threading in win32

On Thu, 13 Oct 2005, Shea Martin wrote:

>>> Only version 1 allows teh gui to remain responsive.  Unfortunately it does 
>>> not capture the output of the copy command.  I would like to something 
>>> with a fork, though win32 ruby does not seem to support it.
>>> 
>>> Any ideas.
>> 
>> 
>> i think reading from pipes should not block the whole process in windows, 
>> at
>> least this works fine on my win system:
>> 
>>   Thread::abort_on_exception = true
>>   t = Thread::new{ IO::popen("tree c:").read }
>>   (4 << 2).times{ p 42; sleep 0.42 }
>>   puts t.value
>> 
>> does it work on yours?
>> 
>> perhaps you need something like
>> 
>>   #version 4
>>   def runCommand( cmd )
>>     Thread::new do
>>       IO::popen("#{ cmd 2>&1 }"){|pipe| pipe.each{|line| addText line}}
>>     end
>>   end
>> 
>> which is to say spawn the thread and let it go.  you'll need to prevent two
>> commands being run at once too...
>> 
>> hth.
>> 
>> -a
>
>
> Everything works for fine when cmd = "tree C:\ /F". The text area is 
> updating, with gobs of output, and I can still use the scroll bars, etc.
> But when cmd = "copy /Y 1GB_FILE.BIG BAK_1GB_FILE.BIG", the problem occurrs. 
> Scrollbars don't work, etc. I guess this must be a windows limitation.  This 
> is a 3.2 GHz machine with H/T enabled, and 2GB of RAM, so I don't think it is 
> a h/w limitation (though it is only IDE).  Also, if I use the system( cmd ), 
> version it does not happen, and it does not happen if I just copy the file 
> (manually) while running the gui.  I'll have to try it when I get home 
> tonight on my solaris and linux boxen.
>
> What happens when you try cmd = "copy /Y 1GB_FILE.BIG BAK_1GB_FILE.BIG"?

it hangs.  but this is no fault of ruby - it is some crappy detail of copy
and/or the way windows interacts with it.  for instance, this program manages
to copy huge files just fine while background threads/processes continue to
run, new ones can be started, and the gui works all the while:

     require "tk"
     require "fileutils"

     gb = 2 ** 30
     mb = 2 ** 20
     kb = 2 ** 10

     unless test ?e, 'gb'
       puts "writing file 'gb'. be patient..."
       buf = "\0" * mb
       open('gb', 'w'){|f| kb.times{ f.write buf }}
       puts "wrote 'gb'"
     end

     FileUtils::rm_rf 'gb2'

     Thread::abort_on_exception = true

     thread_runner = lambda do
       Thread::new do
         program = <<-ruby
           STDERR.reopen STDOUT
           STDOUT.sync = true
           loop{ p [Process::pid, Time::now]; sleep 0.42 }
         ruby
         pipe = IO::popen "ruby", "rb+"
         pipe.write program
         pipe.close_write
         pipe.each do |line|
           puts line
         end
       end
     end

     thread_runner2 = lambda do
       Thread::new do
         loop do
           if test ?e, 'gb2'
             size = File::stat('gb2').size
             p 'gb2' => size
             break if size == gb
           end
           sleep 0.42
         end
       end
       Thread::new do
         FileUtils::cp 'gb', 'gb2'
       end
     end

     TkButton::new(nil,
       "text" => "start thread/process",
       "command" => thread_runner).pack( "fill" =>"x")

     TkButton::new(nil,
       "text" => "huge copy",
       "command" => thread_runner2).pack( "fill" =>"x")

     TkButton::new(nil,
       "text" => "say hello",
       "command" => lambda{puts "HELLO"}).pack( "fill" =>"x")


     TkButton::new(nil,
       "text" => 'quit',
       "command" => lambda{exit}).pack("fill" => "x")


     Tk::mainloop


hth.


-a
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