/usr/share/perl5/XML/Filter/Reindent.pm is in libxml-filter-reindent-perl 0.03-7.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 | package XML::Filter::Reindent;
use strict;
use XML::Filter::DetectWS;
use vars qw{ $VERSION @ISA };
$VERSION = '0.03';
@ISA = qw{ XML::Filter::DetectWS };
sub MAYBE (%) { 2 }
sub new
{
my $class = shift;
my $self = $class->SUPER::new (@_);
# Use one space per indent level (by default)
$self->{Tab} = " " unless defined $self->{Tab};
# Note that this is a PerlSAX filter so we use the XML newline ("\x0A"),
# not the Perl output newline ("\n"), by default.
$self->{Newline} = "\x0A" unless defined $self->{Newline};
$self;
}
# Indent the element if its parent element says so
sub indent_element
{
my ($self, $event, $parent_says_indent) = @_;
return $parent_says_indent;
}
# Always indent children unless element (or its ancestor) has
# xml:space="preserve" attribute
sub indent_children
{
my ($self, $event) = @_;
return $event->{PreserveWS} ? 0 : MAYBE;
}
sub start_element
{
my ($self, $event) = @_;
my $parent = $self->{ParentStack}->[-1];
my $level = $self->{Level}++;
$self->SUPER::start_element ($event);
my $parent_says_indent = $parent->{IndentChildren} ? 1 : 0;
# init with 1 if parent says MAYBE
$event->{Indent} = $self->indent_element ($event, $parent_says_indent) ?
$level : undef;
$event->{IndentChildren} = $self->indent_children ($event);
}
sub end_element
{
my ($self, $event) = @_;
my $start_element = $self->{ParentStack}->[-1];
if ($start_element->{IndentChildren} == MAYBE)
{
my $q = $self->{EventQ};
my $prev = $q->[-1];
if ($prev == $start_element)
{
# End tag follows start tag: compress tag
$start_element->{Compress} = 1;
$event->{Compress} = 1;
#?? could detect if it contains only ignorable_ws
}
elsif ($prev->{EventType} eq 'characters')
{
if ($q->[-2] == $start_element)
{
# Element has only one child, a text node.
# Print element as: <a>text here</a>
delete $prev->{Indent};
$start_element->{IndentChildren} = 0;
}
}
}
my $level = --$self->{Level};
$event->{Indent} = $start_element->{IndentChildren} ? $level : undef;
my $compress = $start_element->{Compress};
if ($compress)
{
$event->{Compress} = $compress;
delete $event->{Indent};
}
$self->SUPER::end_element ($event);
}
sub end_document
{
my ($self, $event) = @_;
$self->push_event ('end_document', $event || {});
$self->flush (0); # send remaining events
}
sub push_event
{
my ($self, $type, $event) = @_;
$event->{EventType} = $type;
if ($type =~ /^(characters|comment|processing_instruction|entity_reference|cdata)$/)
{
my $indent_kids = $self->{ParentStack}->[-1]->{IndentChildren} ? 1 : 0;
$event->{Indent} = $indent_kids ? $self->{Level} : undef;
}
my $q = $self->{EventQ};
push @$q, $event;
$self->flush (4); # keep 4 events on the stack (maybe 3 is enough)
}
sub flush
{
my ($self, $keep) = @_;
my $q = $self->{EventQ};
my $result;
while (@$q > $keep)
{
my $head = $q->[0];
# print "head=" . $head->{EventType} . " indent=" . $head->{Indent} . "\n";
if ($head->{EventType} =~ /ws|ignorable/)
{
my $next = $q->[1];
my $indent = $next->{Indent};
if (defined $indent) # fix existing indent
{
$head->{Data} = $self->{Newline} . ($self->{Tab} x $indent);
$result = $self->send (2);
}
else # remove existing indent
{
shift @$q;
$result = $self->send (1);
}
#?? remove keys: Indent, ...
}
else
{
my $indent = $head->{Indent};
if (defined $indent) # insert indent
{
unshift @$q, { EventType => 'ws',
Data => $self->{Newline} . ($self->{Tab} x $indent) };
$result = $self->send (2);
}
else # no indent - leave as is
{
$result = $self->send (1);
}
}
}
return $result;
}
sub send
{
my ($self, $i) = @_;
my $q = $self->{EventQ};
my $result;
while ($i--)
{
my $event = shift @$q;
my $type = $event->{EventType};
delete $event->{EventType};
#print "TYPE=$type " . join(",", map { "$_=" . $event->{$_} } keys %$event) . "\n";
$result = $self->{Callback}->{$type}->($event);
}
return $result;
}
1; # package return code
=head1 NAME
XML::Filter::Reindent - Reformats whitespace for pretty printing XML
=head1 SYNOPSIS
use XML::Handler::Composer;
use XML::Filter::Reindent;
my $composer = new XML::Handler::Composer (%OPTIONS);
my $indent = new XML::Filter::Reindent (Handler => $composer, %OPTIONS);
=head1 DESCRIPTION
XML::Filter::Reindent is a sub class of L<XML::Filter::DetectWS>.
XML::Filter::Reindent can be used as a PerlSAX filter to reformat an
XML document before sending it to a PerlSAX handler that prints it
(like L<XML::Handler::Composer>.)
Like L<XML::Filter::DetectWS>, it detects ignorable whitespace and blocks of
whitespace characters in certain places. It uses this information and
information supplied by the user to determine where whitespace may be
modified, deleted or inserted.
Based on the indent settings, it then modifies, inserts and deletes characters
and ignorable_whitespace events accordingly.
This is just a first stab at the implementation.
It may be buggy and may change completely!
=head1 Constructor Options
=over 4
=item * Handler
The PerlSAX handler (or filter) that will receive the PerlSAX events from this
filter.
=item * Tab (Default: one space)
The number of spaces per indent level for elements etc. in document content.
=item * Newline (Default: "\x0A")
The newline to use when re-indenting.
The default is the internal newline used by L<XML::Parser>, L<XML::DOM> etc.,
and should be fine when used in combination with L<XML::Handler::Composer>.
=back
=head1 $self->indent_children ($start_element_event)
This method determines whether children of a certain element
may be reformatted.
The default implementation checks the PreserveWS parameter of the specified
start_element event and returns 0 if it is set or MAYBE otherwise.
The value MAYBE (2) indicates that further investigation is needed, e.g.
by examining the element contents. A value of 1 means yes, indent the
child nodes, no further investigation is needed.
NOTE: the PreserveWS parameter is set by the parent class,
L<XML::Filter::DetectWS>, when the element or one of its ancestors has
the attribute xml:space="preserve".
Override this method to tweak the behavior of this class.
=head1 $self->indent_element ($start_element_event, $parent_says_indent)
This method determines whether a certain element may be re-indented.
The default implementation returns the value of the $parent_says_indent
parameter, which was set to the value returned by indent_children for the
parent element. In other words, the element will be re-indented if the
parent element allows it.
Override this method to tweak the behavior of this class.
I'm not sure how useful this hook is. Please provide feedback!
=head1 Current Implementation
The current implementation puts all incoming Perl SAX events in a queue for
further processing. When determining which nodes should be re-indented,
it sometimes needs information from previous events, hence the use of the
queue.
The parameter (Compress => 1) is added to
matching start_element and end_element events with no events in between
This indicates to an XML printer that a compressed notation can be used,
e.g <foo/>.
If an element allows reformatting of its contents (xml:space="preserve" was
not active and indent_children returned MAYBE), the element
contents will be reformatted unless it only has one child node and that
child is a regular text node (characters event.)
In that case, the element will be printed as <foo>text contents</foo>.
If you want element nodes with just one text child to be reindented as well,
simply override indent_children to return 1 instead of MAYBE (2.)
This behavior may be changed or extended in the future.
=head1 CAVEATS
This code is highly experimental!
It has not been tested well and the API may change.
The code that detects blocks of whitespace at potential indent positions
may need some work.
=head1 AUTHOR
Original Author is Enno Derksen.
Send bug reports, hints, tips, suggestions to T.J. Mather at
<F<tjmather@tjmather.com>>.
=cut
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