in reply to Re: Tk::ExecuteCommand - GUI not responding by executing longer running script
in thread Tk::ExecuteCommand - GUI not responding by executing longer running script

for my application would be really better, if I could just change the Tk::ExecuteCommand and not use threads

I think the change is needed somewhere in these 2 functions in Tk::ExecuteCommand (http://search.cpan.org/src/LUSOL/tkjuke-1.0.6/Tk/ExecuteCommand.pm): 
sub _read_stdout {

    # Called when input is available for the output window.  Also chec
+ks
    # to see if the user has clicked Cancel.

    my($self) = @_;

    if ($self->{-finish}) {
    $self->kill_command;
    } else {
    my $h = $self->{-handle};
    if ( sysread $h, $_, 4096 ) {
        my $t = $self->Subwidget('text');
        $t->insert('end', $_);
        $t->yview('end');
    } else {
        $self->{-finish} = 1;
    }
    }
    
} # end _read_stdout

sub execute_command {

    # Execute the command and capture stdout/stderr.

    my($self) = @_;
    
    my $h = IO::Handle->new;
    die "IO::Handle->new failed." unless defined $h;
    $self->{-handle} = $h;

    $self->{-pid} = open $h, $self->{-command} . ' 2>&1 |';
    if (not defined $self->{-pid}) {
    $self->Subwidget('text')->insert('end',
            "'" . $self->{-command} . "' : $!\n");
    $self->kill_command;
    return;
    }
    $h->autoflush(1);
    $self->fileevent($h, 'readable' => [\&_read_stdout, $self]);

    my $doit = $self->Subwidget('doit');
    $doit->configure(
        -text    => 'Cancel',
        -relief  => 'raised',
        -state   => 'normal',
        -command => [\&kill_command, $self],
    );

    my $doit_bg = ($doit->configure(-background))[3];
    $self->_flash_doit(-background => $doit_bg, qw/cyan 500/);

    $self->waitVariable(\$self->{-finish});
    
} # end execute_command

[download]
... is it actually possible to solve my problem so easily - just with changing this module (replace somehow the fileevent, which could be the problem)?
  • Comment on Re^2: Tk::ExecuteCommand - GUI not responding by executing longer running script
  • Download Code

Replies are listed 'Best First'.
Re^3: Tk::ExecuteCommand - GUI not responding by executing longer running script
by zentara (Cardinal) on Feb 05, 2008 at 21:12 UTC
    Hi, see Perl/Tk App and Interprocess Communication for how someone else solved it on win32. You can "roll-your-own" Tk::ExecuteCommand by just popping a text widget in a toplevel windoow, and feed results into from a thread. You will need a timer to constantly pull (read the pipe) instead of a fileevent. You setup the timer to run very fast, like 5 ms, and in the callback, read the pipe. Using the Win32::Pipe module may also help. You can use the timer to read a shared variable from a thread, as an alternative using threads.
    I'm not really a human, but I play one on earth. Cogito ergo sum a bum
[reply]
      Thank you for your help!

      finally I solved it with threads: 
      #!/usr/bin/perl
use threads;
use threads::shared;
require Thread::Queue;

$Q = new Thread::Queue;

share $Script;
share $Terminate;
share $start_work;

$Terminate =0;
$start_work = 0;

threads->new(\&worker)->detach;

use Tk;
require Tk::ROText;
$top = MainWindow->new;
$text = $top->Scrolled('ROText');
    $text->pack(qw/-expand 1 -fill both/);

$b_startdir = $top->Button(
    -text    => "Start command",
    -width   => 12,
    -command => sub {
        $Script = "ping example.org";
        $start_work = 1;
        }
)->pack( -side => 'right' );


my $repeat;
$repeat = $top->repeat( 300 => sub {
    eval {
    while ($Q->pending) {
      my $buffer = $Q->dequeue;
      return unless $buffer;
      
      $text->insert('end', $buffer);
      $text->see('end');
    }
    };
    if ($@) {
      warn "$@";
      $repeat->cancel;
    }
} );

MainLoop;
$Terminate = 1;

sub worker {
  while(!$Terminate){
    if ($Script && $start_work) {
      open PROC, "$Script 2>&1 |" or die "ERR: unable to start $Script
+\n";
      while (sysread(PROC, my $buffer, 1024) > 0) {
        $Q->enqueue($buffer);
        if (!$start_work) {last;}
      }
      close PROC;
      $Script = undef;
      $start_work = 0;
    } else {
      sleep 1;
    }
  }
}

      [download]
[reply]
[d/l]
        So after all I've got still a small problem here:
        When I insert the command output into the text window, it writes squares at the end of some lines (probalby instead of some non-printable end-of-line character)

        -> do you know how could I format the string to remove such non-printable characters?

        UPDATE:
        I solved it with a small character replace before I insert it in the ROText widget in the repeat loop:
        $buffer =~ s/\x0D\x0A/\n/g;
[reply]
[d/l]

In Section Seekers of Perl Wisdom