/usr/share/perl5/Tree/Simple/Visitor/FromNestedHash.pm is in libtree-simple-visitorfactory-perl 0.15-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 | package Tree::Simple::Visitor::FromNestedHash;
use strict;
use warnings;
our $VERSION = '0.15';
use Scalar::Util qw(blessed);
use base qw(Tree::Simple::Visitor);
sub new {
my ($_class) = @_;
my $class = ref($_class) || $_class;
my $visitor = {};
bless($visitor, $class);
$visitor->_init();
return $visitor;
}
sub _init {
my ($self) = @_;
$self->{hash_tree} = undef;
$self->SUPER::_init();
}
sub setHashTree {
my ($self, $hash_tree) = @_;
(defined($hash_tree) && ref($hash_tree) eq 'HASH')
|| die "Insufficient Arguments : You must supply a valid HASH reference";
# validate the tree ...
# it must not be empty
(scalar keys %{$hash_tree} == 1)
|| die "Insufficient Arguments : The hash tree provided must be a single rooted tree";
$self->{hash_tree} = $hash_tree;
}
sub visit {
my ($self, $tree) = @_;
(blessed($tree) && $tree->isa("Tree::Simple"))
|| die "Insufficient Arguments : You must supply a valid Tree::Simple object";
$self->_buildTree(
$tree,
$self->{hash_tree},
$self->getNodeFilter(),
$self->includeTrunk()
);
}
sub _buildTree {
my ($self, $tree, $hash, $node_filter, $include_trunk) = @_;
foreach my $key (sort keys %{$hash}) {
my $node = $key;
$node = $node_filter->($node) if $node_filter;
my $new_tree;
if ($include_trunk) {
$tree->setNodeValue($node);
$new_tree = $tree;
}
else {
$new_tree = Tree::Simple->new($node);
$tree->addChild($new_tree);
}
$self->_buildTree($new_tree, $hash->{$key}, $node_filter)
if ref($hash->{$key}) eq 'HASH';
}
}
1;
__END__
=head1 NAME
Tree::Simple::Visitor::FromNestedHash - A Visitor for creating Tree::Simple objects from nested hash trees.
=head1 SYNOPSIS
use Tree::Simple::Visitor::FromNestedHash;
my $visitor = Tree::Simple::Visitor::FromNestedHash->new();
# given this nested hash tree
my $hash_tree = {
Root => {
Child1 => {
GrandChild1 => {},
GrandChild2 => {}
},
Child2 => {}
}
};
# set the array tree we
# are going to convert
$visitor->setHashTree($hash_tree);
$tree->accept($visitor);
# this then creates the equivalent Tree::Simple object:
# Tree::Simple->new("Root")
# ->addChildren(
# Tree::Simple->new("Child1")
# ->addChildren(
# Tree::Simple->new("GrandChild1"),
# Tree::Simple->new("GrandChild2")
# ),
# Tree::Simple->new("Child2"),
# );
=head1 DESCRIPTION
Given a tree constructed from nested hashes, this Visitor will create the equivalent Tree::Simple hierarchy.
=head1 METHODS
=over 4
=item B<new>
There are no arguments to the constructor the object will be in its default state. You can use the C<setNodeFilter> methods to customize its behavior.
=item B<setNodeFilter ($filter_function)>
This method accepts a CODE reference as its C<$filter_function> argument and throws an exception if it is not a code reference. This code reference is used to filter the tree nodes as they are created, the C<$filter_function> is passed the node value extracted from the hash prior to it being inserted into the tree being built. The C<$filter_function> is expected to return the value desired for inclusion into the tree.
=item B<setHashTree ($hash_tree)>
This method is used to set the C<$hash_tree> that our Tree::Simple hierarchy will be constructed from. It must be in the following form:
{
Root => {
Child1 => {
GrandChild1 => {},
GrandChild2 => {}
},
Child2 => {}
}
}
Basically each key in the hash is considered a node, values are ignored unless it is a hash reference with at least one key in it, in which case it is interpreted as containing the children of the node created from the key.
The tree is validated prior being accepted, if it fails validation an exception will be thrown. The rules are as follows;
=over 4
=item The hash tree must not be empty.
It makes not sense to create a tree out of nothing, so it is assumed that this is a sign of something wrong.
=item The hash tree must be a single rooted tree.
The hash tree should have only one key in it's first level, if it has more than one, then it is not a single rooted tree.
=back
B<NOTE:> Hash keys are sorted ascii-betically before being added to the tree, this results in a somewhat more predictable hierarchy.
=item B<visit ($tree)>
This is the method that is used by Tree::Simple's C<accept> method. It can also be used on its own, it requires the C<$tree> argument to be a Tree::Simple object (or derived from a Tree::Simple object), and will throw and exception otherwise.
=back
=head1 BUGS
None that I am aware of. Of course, if you find a bug, let me know, and I will be sure to fix it.
=head1 CODE COVERAGE
See the B<CODE COVERAGE> section in L<Tree::Simple::VisitorFactory> for more information.
=head1 SEE ALSO
These Visitor classes are all subclasses of B<Tree::Simple::Visitor>, which can be found in the B<Tree::Simple> module, you should refer to that module for more information.
=head1 AUTHOR
stevan little, E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2004, 2005 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
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