Hello,

I've written a script to print the Process Tree. To be able to print it nicely I decided to use Data::TreeDumper.

Here you can see the code:

#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper;
use Tree::Simple;
use Tree::Simple::View::HTML;
use Data::TreeDumper;
use Win32::Process::Info;

use 5.010;
use feature qw(say);

############################################################
# Get Subprocesses
############################################################
my $pi = Win32::Process::Info->new();
my %sub_pids = $pi->Subprocesses();

remove_win32_subprocess_recursion(\%sub_pids);
add_win32_subprocess_root_entry(\%sub_pids);


# e.g. 'ROOT' => [204,5944,3824,0]
sub add_win32_subprocess_root_entry
{
    my( $ref_subs ) = @_;

    my @total_sub_pid_list;
    for my $ref_sub_pid_list (values %$ref_subs)
    {
        for my $sub_pid (@$ref_sub_pid_list)
        {
            push(@total_sub_pid_list, $sub_pid);
        }
    }

    my @root_pid_list;
    for my $pid (keys %$ref_subs)
    {
        unless( $pid ~~ @total_sub_pid_list )
        {
            push(@root_pid_list, $pid);
        }
    }

    $ref_subs->{'ROOT'} = [@root_pid_list];
}

# remove win32 subprocess recursions
# e.g. '0' => [0,4]
# -->  '0' => [4]
sub remove_win32_subprocess_recursion
{
    my( $ref_subs ) = @_;

    while( my ($pid, $ref_sub_pid_list) = each %$ref_subs )
    {
        if( $pid ~~ $ref_sub_pid_list )
        {
            @$ref_sub_pid_list = grep(!/$pid/, @$ref_sub_pid_list); 
        }
    }
}

############################################################
# Create Process Tree
############################################################
my $root_pid = 'ROOT';
my $pid_tree = Tree::Simple->new($root_pid, Tree::Simple->ROOT);
build_pid_tree($root_pid, $pid_tree);
$pid_tree->DESTROY();

sub build_pid_tree
{
    my ($pid, $pid_tree) = @_;

    if( scalar @{ $sub_pids{$pid} } == 0 )
    {        
        return;        
    }
    
    for my $item (  @{ $sub_pids{$pid} } )
    {        
        build_pid_tree( $item, Tree::Simple->new($item, $pid_tree) );
    }    
}

############################################################
# TRAVERSE TREE
############################################################
print "Relevant Information:\n";
$pid_tree->traverse( \&print_tree );
print "\n";

sub print_tree
{
    my ($tree) = @_;
    print (("\t" x $tree->getDepth()), $tree->getNodeValue(), "\n");
}

############################################################
# View Tree (Data::TreeDumper)
############################################################
print "Unfiltered Tree:Simple tree:\n";
print DumpTree($pid_tree, 'Win32 Process Tree');
print "\n";

print "Filtered Tree::Simple tree:\n";
print DumpTree($pid_tree, 'Win32 Process Tree', FILTER => sub
{
    my $s = shift;

    if('Tree::Simple' eq ref $s)
    {
        # TODO
    }
    
    return(Data::TreeDumper::DefaultNodesToDisplay($s)) ;
});
[download]

The script is detecting all running processes. Then all PIDs are put into a tree (by using Tree::Simple).

To show you what I want to have I traversed the tree and printed it.

Now I want to do the same printing with Data::TreeDumper. But I am not getting it. I do not really understand the filters. I read the help, but I don't get it.

The input is a Tree::Simple process tree. But this tree has of course a lot of more information in which I am NOT interested. You can see this tree by looking at the output directly behind print "Unfiltered Tree:Simple tree:\n";.

After the print "Filtered Tree::Simple tree:\n"; I try to only print the content of the nodes. But I do not understand the filter.

I know that the return value of the filter is consisting of three parts. A node type, an eventual new structure and a list of 'keys' to display.

For example I tried the following to only get the nodes:

print DumpTree($pid_tree, 'Win32 Process Tree', FILTER => sub
{
    my $s = shift;

    if('Tree::Simple' eq ref $s)
    {
        return( 'SCALAR', undef, $_{'node'} );
    }
    
    return(Data::TreeDumper::DefaultNodesToDisplay($s)) ;
});
[download]

But I get a weird result and some warnings:

Filtered Tree::Simple tree:
Win32 Process Tree blessed in 'Tree::Simple'
`-  = undef  [S1]
[download]

I also tried it with an array instead of the scalar. But I also get weird results.

Thanks for your help.

Greetings,

Dirk