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/MissionCockpit/tags/V0.2.5/perl/lib/Thread/Queue.pm
0,0 → 1,481
package Thread::Queue;
use strict;
use warnings;
our $VERSION = '2.11';
use threads::shared 1.21;
use Scalar::Util 1.10 qw(looks_like_number blessed reftype refaddr);
# Carp errors from threads::shared calls should complain about caller
our @CARP_NOT = ("threads::shared");
# Predeclarations for internal functions
my ($validate_count, $validate_index);
# Create a new queue possibly pre-populated with items
sub new
{
my $class = shift;
my @queue :shared = map { shared_clone($_) } @_;
return bless(\@queue, $class);
}
# Add items to the tail of a queue
sub enqueue
{
my $queue = shift;
lock(@$queue);
push(@$queue, map { shared_clone($_) } @_)
and cond_signal(@$queue);
}
# Return a count of the number of items on a queue
sub pending
{
my $queue = shift;
lock(@$queue);
return scalar(@$queue);
}
# Return 1 or more items from the head of a queue, blocking if needed
sub dequeue
{
my $queue = shift;
lock(@$queue);
my $count = @_ ? $validate_count->(shift) : 1;
# Wait for requisite number of items
cond_wait(@$queue) until (@$queue >= $count);
cond_signal(@$queue) if (@$queue > $count);
# Return single item
return shift(@$queue) if ($count == 1);
# Return multiple items
my @items;
push(@items, shift(@$queue)) for (1..$count);
return @items;
}
# Return items from the head of a queue with no blocking
sub dequeue_nb
{
my $queue = shift;
lock(@$queue);
my $count = @_ ? $validate_count->(shift) : 1;
# Return single item
return shift(@$queue) if ($count == 1);
# Return multiple items
my @items;
for (1..$count) {
last if (! @$queue);
push(@items, shift(@$queue));
}
return @items;
}
# Return an item without removing it from a queue
sub peek
{
my $queue = shift;
lock(@$queue);
my $index = @_ ? $validate_index->(shift) : 0;
return $$queue[$index];
}
# Insert items anywhere into a queue
sub insert
{
my $queue = shift;
lock(@$queue);
my $index = $validate_index->(shift);
return if (! @_); # Nothing to insert
# Support negative indices
if ($index < 0) {
$index += @$queue;
if ($index < 0) {
$index = 0;
}
}
# Dequeue items from $index onward
my @tmp;
while (@$queue > $index) {
unshift(@tmp, pop(@$queue))
}
# Add new items to the queue
push(@$queue, map { shared_clone($_) } @_);
# Add previous items back onto the queue
push(@$queue, @tmp);
# Soup's up
cond_signal(@$queue);
}
# Remove items from anywhere in a queue
sub extract
{
my $queue = shift;
lock(@$queue);
my $index = @_ ? $validate_index->(shift) : 0;
my $count = @_ ? $validate_count->(shift) : 1;
# Support negative indices
if ($index < 0) {
$index += @$queue;
if ($index < 0) {
$count += $index;
return if ($count <= 0); # Beyond the head of the queue
return $queue->dequeue_nb($count); # Extract from the head
}
}
# Dequeue items from $index+$count onward
my @tmp;
while (@$queue > ($index+$count)) {
unshift(@tmp, pop(@$queue))
}
# Extract desired items
my @items;
unshift(@items, pop(@$queue)) while (@$queue > $index);
# Add back any removed items
push(@$queue, @tmp);
# Return single item
return $items[0] if ($count == 1);
# Return multiple items
return @items;
}
### Internal Functions ###
# Check value of the requested index
$validate_index = sub {
my $index = shift;
if (! defined($index) ||
! looks_like_number($index) ||
(int($index) != $index))
{
require Carp;
my ($method) = (caller(1))[3];
$method =~ s/Thread::Queue:://;
$index = 'undef' if (! defined($index));
Carp::croak("Invalid 'index' argument ($index) to '$method' method");
}
return $index;
};
# Check value of the requested count
$validate_count = sub {
my $count = shift;
if (! defined($count) ||
! looks_like_number($count) ||
(int($count) != $count) ||
($count < 1))
{
require Carp;
my ($method) = (caller(1))[3];
$method =~ s/Thread::Queue:://;
$count = 'undef' if (! defined($count));
Carp::croak("Invalid 'count' argument ($count) to '$method' method");
}
return $count;
};
1;
=head1 NAME
Thread::Queue - Thread-safe queues
=head1 VERSION
This document describes Thread::Queue version 2.11
=head1 SYNOPSIS
use strict;
use warnings;
use threads;
use Thread::Queue;
my $q = Thread::Queue->new(); # A new empty queue
# Worker thread
my $thr = threads->create(sub {
while (my $item = $q->dequeue()) {
# Do work on $item
}
})->detach();
# Send work to the thread
$q->enqueue($item1, ...);
# Count of items in the queue
my $left = $q->pending();
# Non-blocking dequeue
if (defined(my $item = $q->dequeue_nb())) {
# Work on $item
}
# Get the second item in the queue without dequeuing anything
my $item = $q->peek(1);
# Insert two items into the queue just behind the head
$q->insert(1, $item1, $item2);
# Extract the last two items on the queue
my ($item1, $item2) = $q->extract(-2, 2);
=head1 DESCRIPTION
This module provides thread-safe FIFO queues that can be accessed safely by
any number of threads.
Any data types supported by L<threads::shared> can be passed via queues:
=over
=item Ordinary scalars
=item Array refs
=item Hash refs
=item Scalar refs
=item Objects based on the above
=back
Ordinary scalars are added to queues as they are.
If not already thread-shared, the other complex data types will be cloned
(recursively, if needed, and including any C<bless>ings and read-only
settings) into thread-shared structures before being placed onto a queue.
For example, the following would cause L<Thread::Queue> to create a empty,
shared array reference via C<&shared([])>, copy the elements 'foo', 'bar'
and 'baz' from C<@ary> into it, and then place that shared reference onto
the queue:
my @ary = qw/foo bar baz/;
$q->enqueue(\@ary);
However, for the following, the items are already shared, so their references
are added directly to the queue, and no cloning takes place:
my @ary :shared = qw/foo bar baz/;
$q->enqueue(\@ary);
my $obj = &shared({});
$$obj{'foo'} = 'bar';
$$obj{'qux'} = 99;
bless($obj, 'My::Class');
$q->enqueue($obj);
See L</"LIMITATIONS"> for caveats related to passing objects via queues.
=head1 QUEUE CREATION
=over
=item ->new()
Creates a new empty queue.
=item ->new(LIST)
Creates a new queue pre-populated with the provided list of items.
=back
=head1 BASIC METHODS
The following methods deal with queues on a FIFO basis.
=over
=item ->enqueue(LIST)
Adds a list of items onto the end of the queue.
=item ->dequeue()
=item ->dequeue(COUNT)
Removes the requested number of items (default is 1) from the head of the
queue, and returns them. If the queue contains fewer than the requested
number of items, then the thread will be blocked until the requisite number
of items are available (i.e., until other threads <enqueue> more items).
=item ->dequeue_nb()
=item ->dequeue_nb(COUNT)
Removes the requested number of items (default is 1) from the head of the
queue, and returns them. If the queue contains fewer than the requested
number of items, then it immediately (i.e., non-blocking) returns whatever
items there are on the queue. If the queue is empty, then C<undef> is
returned.
=item ->pending()
Returns the number of items still in the queue.
=back
=head1 ADVANCED METHODS
The following methods can be used to manipulate items anywhere in a queue.
To prevent the contents of a queue from being modified by another thread
while it is being examined and/or changed, L<lock|threads::shared/"lock
VARIABLE"> the queue inside a local block:
{
lock($q); # Keep other threads from changing the queue's contents
my $item = $q->peek();
if ($item ...) {
...
}
}
# Queue is now unlocked
=over
=item ->peek()
=item ->peek(INDEX)
Returns an item from the queue without dequeuing anything. Defaults to the
the head of queue (at index position 0) if no index is specified. Negative
index values are supported as with L<arrays|perldata/"Subscripts"> (i.e., -1
is the end of the queue, -2 is next to last, and so on).
If no items exists at the specified index (i.e., the queue is empty, or the
index is beyond the number of items on the queue), then C<undef> is returned.
Remember, the returned item is not removed from the queue, so manipulating a
C<peek>ed at reference affects the item on the queue.
=item ->insert(INDEX, LIST)
Adds the list of items to the queue at the specified index position (0
is the head of the list). Any existing items at and beyond that position are
pushed back past the newly added items:
$q->enqueue(1, 2, 3, 4);
$q->insert(1, qw/foo bar/);
# Queue now contains: 1, foo, bar, 2, 3, 4
Specifying an index position greater than the number of items in the queue
just adds the list to the end.
Negative index positions are supported:
$q->enqueue(1, 2, 3, 4);
$q->insert(-2, qw/foo bar/);
# Queue now contains: 1, 2, foo, bar, 3, 4
Specifying a negative index position greater than the number of items in the
queue adds the list to the head of the queue.
=item ->extract()
=item ->extract(INDEX)
=item ->extract(INDEX, COUNT)
Removes and returns the specified number of items (defaults to 1) from the
specified index position in the queue (0 is the head of the queue). When
called with no arguments, C<extract> operates the same as C<dequeue_nb>.
This method is non-blocking, and will return only as many items as are
available to fulfill the request:
$q->enqueue(1, 2, 3, 4);
my $item = $q->extract(2) # Returns 3
# Queue now contains: 1, 2, 4
my @items = $q->extract(1, 3) # Returns (2, 4)
# Queue now contains: 1
Specifying an index position greater than the number of items in the
queue results in C<undef> or an empty list being returned.
$q->enqueue('foo');
my $nada = $q->extract(3) # Returns undef
my @nada = $q->extract(1, 3) # Returns ()
Negative index positions are supported. Specifying a negative index position
greater than the number of items in the queue may return items from the head
of the queue (similar to C<dequeue_nb>) if the count overlaps the head of the
queue from the specified position (i.e. if queue size + index + count is
greater than zero):
$q->enqueue(qw/foo bar baz/);
my @nada = $q->extract(-6, 2); # Returns () - (3+(-6)+2) <= 0
my @some = $q->extract(-6, 4); # Returns (foo) - (3+(-6)+4) > 0
# Queue now contains: bar, baz
my @rest = $q->extract(-3, 4); # Returns (bar, baz) - (2+(-3)+4) > 0
=back
=head1 NOTES
Queues created by L<Thread::Queue> can be used in both threaded and
non-threaded applications.
=head1 LIMITATIONS
Passing objects on queues may not work if the objects' classes do not support
sharing. See L<threads::shared/"BUGS AND LIMITATIONS"> for more.
Passing array/hash refs that contain objects may not work for Perl prior to
5.10.0.
=head1 SEE ALSO
Thread::Queue Discussion Forum on CPAN:
L<http://www.cpanforum.com/dist/Thread-Queue>
Annotated POD for Thread::Queue:
L<http://annocpan.org/~JDHEDDEN/Thread-Queue-2.11/lib/Thread/Queue.pm>
Source repository:
L<http://code.google.com/p/thread-queue/>
L<threads>, L<threads::shared>
=head1 MAINTAINER
Jerry D. Hedden, S<E<lt>jdhedden AT cpan DOT orgE<gt>>
=head1 LICENSE
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.
=cut

/MissionCockpit/tags/V0.2.5/perl/lib/XML/Simple.pm
0,0 → 1,3284
# $Id: Simple.pm,v 1.40 2007/08/15 10:36:48 grantm Exp $
package XML::Simple;
=head1 NAME
XML::Simple - Easy API to maintain XML (esp config files)
=head1 SYNOPSIS
use XML::Simple;
my $ref = XMLin([<xml file or string>] [, <options>]);
my $xml = XMLout($hashref [, <options>]);
Or the object oriented way:
require XML::Simple;
my $xs = XML::Simple->new(options);
my $ref = $xs->XMLin([<xml file or string>] [, <options>]);
my $xml = $xs->XMLout($hashref [, <options>]);
(or see L<"SAX SUPPORT"> for 'the SAX way').
To catch common errors:
use XML::Simple qw(:strict);
(see L<"STRICT MODE"> for more details).
=cut
# See after __END__ for more POD documentation
# Load essentials here, other modules loaded on demand later
use strict;
use Carp;
require Exporter;
##############################################################################
# Define some constants
#
use vars qw($VERSION @ISA @EXPORT @EXPORT_OK $PREFERRED_PARSER);
@ISA = qw(Exporter);
@EXPORT = qw(XMLin XMLout);
@EXPORT_OK = qw(xml_in xml_out);
$VERSION = '2.18';
$PREFERRED_PARSER = undef;
my $StrictMode = 0;
my @KnownOptIn = qw(keyattr keeproot forcecontent contentkey noattr
searchpath forcearray cache suppressempty parseropts
grouptags nsexpand datahandler varattr variables
normalisespace normalizespace valueattr);
my @KnownOptOut = qw(keyattr keeproot contentkey noattr
rootname xmldecl outputfile noescape suppressempty
grouptags nsexpand handler noindent attrindent nosort
valueattr numericescape);
my @DefKeyAttr = qw(name key id);
my $DefRootName = qq(opt);
my $DefContentKey = qq(content);
my $DefXmlDecl = qq(<?xml version='1.0' standalone='yes'?>);
my $xmlns_ns = 'http://www.w3.org/2000/xmlns/';
my $bad_def_ns_jcn = '{' . $xmlns_ns . '}'; # LibXML::SAX workaround
##############################################################################
# Globals for use by caching routines
#
my %MemShareCache = ();
my %MemCopyCache = ();
##############################################################################
# Wrapper for Exporter - handles ':strict'
#
sub import {
# Handle the :strict tag
$StrictMode = 1 if grep(/^:strict$/, @_);
# Pass everything else to Exporter.pm
@_ = grep(!/^:strict$/, @_);
goto &Exporter::import;
}
##############################################################################
# Constructor for optional object interface.
#
sub new {
my $class = shift;
if(@_ % 2) {
croak "Default options must be name=>value pairs (odd number supplied)";
}
my %known_opt;
@known_opt{@KnownOptIn, @KnownOptOut} = (undef) x 100;
my %raw_opt = @_;
my %def_opt;
while(my($key, $val) = each %raw_opt) {
my $lkey = lc($key);
$lkey =~ s/_//g;
croak "Unrecognised option: $key" unless(exists($known_opt{$lkey}));
$def_opt{$lkey} = $val;
}
my $self = { def_opt => \%def_opt };
return(bless($self, $class));
}
##############################################################################
# Sub: _get_object()
#
# Helper routine called from XMLin() and XMLout() to create an object if none
# was provided. Note, this routine does mess with the caller's @_ array.
#
sub _get_object {
my $self;
if($_[0] and UNIVERSAL::isa($_[0], 'XML::Simple')) {
$self = shift;
}
else {
$self = XML::Simple->new();
}
return $self;
}
##############################################################################
# Sub/Method: XMLin()
#
# Exported routine for slurping XML into a hashref - see pod for info.
#
# May be called as object method or as a plain function.
#
# Expects one arg for the source XML, optionally followed by a number of
# name => value option pairs.
#
sub XMLin {
my $self = &_get_object; # note, @_ is passed implicitly
my $target = shift;
# Work out whether to parse a string, a file or a filehandle
if(not defined $target) {
return $self->parse_file(undef, @_);
}
elsif($target eq '-') {
local($/) = undef;
$target = <STDIN>;
return $self->parse_string(\$target, @_);
}
elsif(my $type = ref($target)) {
if($type eq 'SCALAR') {
return $self->parse_string($target, @_);
}
else {
return $self->parse_fh($target, @_);
}
}
elsif($target =~ m{<.*?>}s) {
return $self->parse_string(\$target, @_);
}
else {
return $self->parse_file($target, @_);
}
}
##############################################################################
# Sub/Method: parse_file()
#
# Same as XMLin, but only parses from a named file.
#
sub parse_file {
my $self = &_get_object; # note, @_ is passed implicitly
my $filename = shift;
$self->handle_options('in', @_);
$filename = $self->default_config_file if not defined $filename;
$filename = $self->find_xml_file($filename, @{$self->{opt}->{searchpath}});
# Check cache for previous parse
if($self->{opt}->{cache}) {
foreach my $scheme (@{$self->{opt}->{cache}}) {
my $method = 'cache_read_' . $scheme;
my $opt = $self->$method($filename);
return($opt) if($opt);
}
}
my $ref = $self->build_simple_tree($filename, undef);
if($self->{opt}->{cache}) {
my $method = 'cache_write_' . $self->{opt}->{cache}->[0];
$self->$method($ref, $filename);
}
return $ref;
}
##############################################################################
# Sub/Method: parse_fh()
#
# Same as XMLin, but only parses from a filehandle.
#
sub parse_fh {
my $self = &_get_object; # note, @_ is passed implicitly
my $fh = shift;
croak "Can't use " . (defined $fh ? qq{string ("$fh")} : 'undef') .
" as a filehandle" unless ref $fh;
$self->handle_options('in', @_);
return $self->build_simple_tree(undef, $fh);
}
##############################################################################
# Sub/Method: parse_string()
#
# Same as XMLin, but only parses from a string or a reference to a string.
#
sub parse_string {
my $self = &_get_object; # note, @_ is passed implicitly
my $string = shift;
$self->handle_options('in', @_);
return $self->build_simple_tree(undef, ref $string ? $string : \$string);
}
##############################################################################
# Method: default_config_file()
#
# Returns the name of the XML file to parse if no filename (or XML string)
# was provided.
#
sub default_config_file {
my $self = shift;
require File::Basename;
my($basename, $script_dir, $ext) = File::Basename::fileparse($0, '\.[^\.]+');
# Add script directory to searchpath
if($script_dir) {
unshift(@{$self->{opt}->{searchpath}}, $script_dir);
}
return $basename . '.xml';
}
##############################################################################
# Method: build_simple_tree()
#
# Builds a 'tree' data structure as provided by XML::Parser and then
# 'simplifies' it as specified by the various options in effect.
#
sub build_simple_tree {
my $self = shift;
my $tree = $self->build_tree(@_);
return $self->{opt}->{keeproot}
? $self->collapse({}, @$tree)
: $self->collapse(@{$tree->[1]});
}
##############################################################################
# Method: build_tree()
#
# This routine will be called if there is no suitable pre-parsed tree in a
# cache. It parses the XML and returns an XML::Parser 'Tree' style data
# structure (summarised in the comments for the collapse() routine below).
#
# XML::Simple requires the services of another module that knows how to parse
# XML. If XML::SAX is installed, the default SAX parser will be used,
# otherwise XML::Parser will be used.
#
# This routine expects to be passed a filename as argument 1 or a 'string' as
# argument 2. The 'string' might be a string of XML (passed by reference to
# save memory) or it might be a reference to an IO::Handle. (This
# non-intuitive mess results in part from the way XML::Parser works but that's
# really no excuse).
#
sub build_tree {
my $self = shift;
my $filename = shift;
my $string = shift;
my $preferred_parser = $PREFERRED_PARSER;
unless(defined($preferred_parser)) {
$preferred_parser = $ENV{XML_SIMPLE_PREFERRED_PARSER} || '';
}
if($preferred_parser eq 'XML::Parser') {
return($self->build_tree_xml_parser($filename, $string));
}
eval { require XML::SAX; }; # We didn't need it until now
if($@) { # No XML::SAX - fall back to XML::Parser
if($preferred_parser) { # unless a SAX parser was expressly requested
croak "XMLin() could not load XML::SAX";
}
return($self->build_tree_xml_parser($filename, $string));
}
$XML::SAX::ParserPackage = $preferred_parser if($preferred_parser);
my $sp = XML::SAX::ParserFactory->parser(Handler => $self);
$self->{nocollapse} = 1;
my($tree);
if($filename) {
$tree = $sp->parse_uri($filename);
}
else {
if(ref($string) && ref($string) ne 'SCALAR') {
$tree = $sp->parse_file($string);
}
else {
$tree = $sp->parse_string($$string);
}
}
return($tree);
}
##############################################################################
# Method: build_tree_xml_parser()
#
# This routine will be called if XML::SAX is not installed, or if XML::Parser
# was specifically requested. It takes the same arguments as build_tree() and
# returns the same data structure (XML::Parser 'Tree' style).
#
sub build_tree_xml_parser {
my $self = shift;
my $filename = shift;
my $string = shift;
eval {
local($^W) = 0; # Suppress warning from Expat.pm re File::Spec::load()
require XML::Parser; # We didn't need it until now
};
if($@) {
croak "XMLin() requires either XML::SAX or XML::Parser";
}
if($self->{opt}->{nsexpand}) {
carp "'nsexpand' option requires XML::SAX";
}
my $xp = XML::Parser->new(Style => 'Tree', @{$self->{opt}->{parseropts}});
my($tree);
if($filename) {
# $tree = $xp->parsefile($filename); # Changed due to prob w/mod_perl
local(*XML_FILE);
open(XML_FILE, '<', $filename) || croak qq($filename - $!);
$tree = $xp->parse(*XML_FILE);
close(XML_FILE);
}
else {
$tree = $xp->parse($$string);
}
return($tree);
}
##############################################################################
# Method: cache_write_storable()
#
# Wrapper routine for invoking Storable::nstore() to cache a parsed data
# structure.
#
sub cache_write_storable {
my($self, $data, $filename) = @_;
my $cachefile = $self->storable_filename($filename);
require Storable; # We didn't need it until now
if ('VMS' eq $^O) {
Storable::nstore($data, $cachefile);
}
else {
# If the following line fails for you, your Storable.pm is old - upgrade
Storable::lock_nstore($data, $cachefile);
}
}
##############################################################################
# Method: cache_read_storable()
#
# Wrapper routine for invoking Storable::retrieve() to read a cached parsed
# data structure. Only returns cached data if the cache file exists and is
# newer than the source XML file.
#
sub cache_read_storable {
my($self, $filename) = @_;
my $cachefile = $self->storable_filename($filename);
return unless(-r $cachefile);
return unless((stat($cachefile))[9] > (stat($filename))[9]);
require Storable; # We didn't need it until now
if ('VMS' eq $^O) {
return(Storable::retrieve($cachefile));
}
else {
return(Storable::lock_retrieve($cachefile));
}
}
##############################################################################
# Method: storable_filename()
#
# Translates the supplied source XML filename into a filename for the storable
# cached data. A '.stor' suffix is added after stripping an optional '.xml'
# suffix.
#
sub storable_filename {
my($self, $cachefile) = @_;
$cachefile =~ s{(\.xml)?$}{.stor};
return $cachefile;
}
##############################################################################
# Method: cache_write_memshare()
#
# Takes the supplied data structure reference and stores it away in a global
# hash structure.
#
sub cache_write_memshare {
my($self, $data, $filename) = @_;
$MemShareCache{$filename} = [time(), $data];
}
##############################################################################
# Method: cache_read_memshare()
#
# Takes a filename and looks in a global hash for a cached parsed version.
#
sub cache_read_memshare {
my($self, $filename) = @_;
return unless($MemShareCache{$filename});
return unless($MemShareCache{$filename}->[0] > (stat($filename))[9]);
return($MemShareCache{$filename}->[1]);
}
##############################################################################
# Method: cache_write_memcopy()
#
# Takes the supplied data structure and stores a copy of it in a global hash
# structure.
#
sub cache_write_memcopy {
my($self, $data, $filename) = @_;
require Storable; # We didn't need it until now
$MemCopyCache{$filename} = [time(), Storable::dclone($data)];
}
##############################################################################
# Method: cache_read_memcopy()
#
# Takes a filename and looks in a global hash for a cached parsed version.
# Returns a reference to a copy of that data structure.
#
sub cache_read_memcopy {
my($self, $filename) = @_;
return unless($MemCopyCache{$filename});
return unless($MemCopyCache{$filename}->[0] > (stat($filename))[9]);
return(Storable::dclone($MemCopyCache{$filename}->[1]));
}
##############################################################################
# Sub/Method: XMLout()
#
# Exported routine for 'unslurping' a data structure out to XML.
#
# Expects a reference to a data structure and an optional list of option
# name => value pairs.
#
sub XMLout {
my $self = &_get_object; # note, @_ is passed implicitly
croak "XMLout() requires at least one argument" unless(@_);
my $ref = shift;
$self->handle_options('out', @_);
# If namespace expansion is set, XML::NamespaceSupport is required
if($self->{opt}->{nsexpand}) {
require XML::NamespaceSupport;
$self->{nsup} = XML::NamespaceSupport->new();
$self->{ns_prefix} = 'aaa';
}
# Wrap top level arrayref in a hash
if(UNIVERSAL::isa($ref, 'ARRAY')) {
$ref = { anon => $ref };
}
# Extract rootname from top level hash if keeproot enabled
if($self->{opt}->{keeproot}) {
my(@keys) = keys(%$ref);
if(@keys == 1) {
$ref = $ref->{$keys[0]};
$self->{opt}->{rootname} = $keys[0];
}
}
# Ensure there are no top level attributes if we're not adding root elements
elsif($self->{opt}->{rootname} eq '') {
if(UNIVERSAL::isa($ref, 'HASH')) {
my $refsave = $ref;
$ref = {};
foreach (keys(%$refsave)) {
if(ref($refsave->{$_})) {
$ref->{$_} = $refsave->{$_};
}
else {
$ref->{$_} = [ $refsave->{$_} ];
}
}
}
}
# Encode the hashref and write to file if necessary
$self->{_ancestors} = [];
my $xml = $self->value_to_xml($ref, $self->{opt}->{rootname}, '');
delete $self->{_ancestors};
if($self->{opt}->{xmldecl}) {
$xml = $self->{opt}->{xmldecl} . "\n" . $xml;
}
if($self->{opt}->{outputfile}) {
if(ref($self->{opt}->{outputfile})) {
my $fh = $self->{opt}->{outputfile};
if(UNIVERSAL::isa($fh, 'GLOB') and !UNIVERSAL::can($fh, 'print')) {
eval { require IO::Handle; };
croak $@ if $@;
}
return($fh->print($xml));
}
else {
local(*OUT);
open(OUT, '>', "$self->{opt}->{outputfile}") ||
croak "open($self->{opt}->{outputfile}): $!";
binmode(OUT, ':utf8') if($] >= 5.008);
print OUT $xml || croak "print: $!";
close(OUT);
}
}
elsif($self->{opt}->{handler}) {
require XML::SAX;
my $sp = XML::SAX::ParserFactory->parser(
Handler => $self->{opt}->{handler}
);
return($sp->parse_string($xml));
}
else {
return($xml);
}
}
##############################################################################
# Method: handle_options()
#
# Helper routine for both XMLin() and XMLout(). Both routines handle their
# first argument and assume all other args are options handled by this routine.
# Saves a hash of options in $self->{opt}.
#
# If default options were passed to the constructor, they will be retrieved
# here and merged with options supplied to the method call.
#
# First argument should be the string 'in' or the string 'out'.
#
# Remaining arguments should be name=>value pairs. Sets up default values
# for options not supplied. Unrecognised options are a fatal error.
#
sub handle_options {
my $self = shift;
my $dirn = shift;
# Determine valid options based on context
my %known_opt;
if($dirn eq 'in') {
@known_opt{@KnownOptIn} = @KnownOptIn;
}
else {
@known_opt{@KnownOptOut} = @KnownOptOut;
}
# Store supplied options in hashref and weed out invalid ones
if(@_ % 2) {
croak "Options must be name=>value pairs (odd number supplied)";
}
my %raw_opt = @_;
my $opt = {};
$self->{opt} = $opt;
while(my($key, $val) = each %raw_opt) {
my $lkey = lc($key);
$lkey =~ s/_//g;
croak "Unrecognised option: $key" unless($known_opt{$lkey});
$opt->{$lkey} = $val;
}
# Merge in options passed to constructor
foreach (keys(%known_opt)) {
unless(exists($opt->{$_})) {
if(exists($self->{def_opt}->{$_})) {
$opt->{$_} = $self->{def_opt}->{$_};
}
}
}
# Set sensible defaults if not supplied
if(exists($opt->{rootname})) {
unless(defined($opt->{rootname})) {
$opt->{rootname} = '';
}
}
else {
$opt->{rootname} = $DefRootName;
}
if($opt->{xmldecl} and $opt->{xmldecl} eq '1') {
$opt->{xmldecl} = $DefXmlDecl;
}
if(exists($opt->{contentkey})) {
if($opt->{contentkey} =~ m{^-(.*)$}) {
$opt->{contentkey} = $1;
$opt->{collapseagain} = 1;
}
}
else {
$opt->{contentkey} = $DefContentKey;
}
unless(exists($opt->{normalisespace})) {
$opt->{normalisespace} = $opt->{normalizespace};
}
$opt->{normalisespace} = 0 unless(defined($opt->{normalisespace}));
# Cleanups for values assumed to be arrays later
if($opt->{searchpath}) {
unless(ref($opt->{searchpath})) {
$opt->{searchpath} = [ $opt->{searchpath} ];
}
}
else {
$opt->{searchpath} = [ ];
}
if($opt->{cache} and !ref($opt->{cache})) {
$opt->{cache} = [ $opt->{cache} ];
}
if($opt->{cache}) {
$_ = lc($_) foreach (@{$opt->{cache}});
foreach my $scheme (@{$opt->{cache}}) {
my $method = 'cache_read_' . $scheme;
croak "Unsupported caching scheme: $scheme"
unless($self->can($method));
}
}
if(exists($opt->{parseropts})) {
if($^W) {
carp "Warning: " .
"'ParserOpts' is deprecated, contact the author if you need it";
}
}
else {
$opt->{parseropts} = [ ];
}
# Special cleanup for {forcearray} which could be regex, arrayref or boolean
# or left to default to 0
if(exists($opt->{forcearray})) {
if(ref($opt->{forcearray}) eq 'Regexp') {
$opt->{forcearray} = [ $opt->{forcearray} ];
}
if(ref($opt->{forcearray}) eq 'ARRAY') {
my @force_list = @{$opt->{forcearray}};
if(@force_list) {
$opt->{forcearray} = {};
foreach my $tag (@force_list) {
if(ref($tag) eq 'Regexp') {
push @{$opt->{forcearray}->{_regex}}, $tag;
}
else {
$opt->{forcearray}->{$tag} = 1;
}
}
}
else {
$opt->{forcearray} = 0;
}
}
else {
$opt->{forcearray} = ( $opt->{forcearray} ? 1 : 0 );
}
}
else {
if($StrictMode and $dirn eq 'in') {
croak "No value specified for 'ForceArray' option in call to XML$dirn()";
}
$opt->{forcearray} = 0;
}
# Special cleanup for {keyattr} which could be arrayref or hashref or left
# to default to arrayref
if(exists($opt->{keyattr})) {
if(ref($opt->{keyattr})) {
if(ref($opt->{keyattr}) eq 'HASH') {
# Make a copy so we can mess with it
$opt->{keyattr} = { %{$opt->{keyattr}} };
# Convert keyattr => { elem => '+attr' }
# to keyattr => { elem => [ 'attr', '+' ] }
foreach my $el (keys(%{$opt->{keyattr}})) {
if($opt->{keyattr}->{$el} =~ /^(\+|-)?(.*)$/) {
$opt->{keyattr}->{$el} = [ $2, ($1 ? $1 : '') ];
if($StrictMode and $dirn eq 'in') {
next if($opt->{forcearray} == 1);
next if(ref($opt->{forcearray}) eq 'HASH'
and $opt->{forcearray}->{$el});
croak "<$el> set in KeyAttr but not in ForceArray";
}
}
else {
delete($opt->{keyattr}->{$el}); # Never reached (famous last words?)
}
}
}
else {
if(@{$opt->{keyattr}} == 0) {
delete($opt->{keyattr});
}
}
}
else {
$opt->{keyattr} = [ $opt->{keyattr} ];
}
}
else {
if($StrictMode) {
croak "No value specified for 'KeyAttr' option in call to XML$dirn()";
}
$opt->{keyattr} = [ @DefKeyAttr ];
}
# Special cleanup for {valueattr} which could be arrayref or hashref
if(exists($opt->{valueattr})) {
if(ref($opt->{valueattr}) eq 'ARRAY') {
$opt->{valueattrlist} = {};
$opt->{valueattrlist}->{$_} = 1 foreach(@{ delete $opt->{valueattr} });
}
}
# make sure there's nothing weird in {grouptags}
if($opt->{grouptags}) {
croak "Illegal value for 'GroupTags' option - expected a hashref"
unless UNIVERSAL::isa($opt->{grouptags}, 'HASH');
while(my($key, $val) = each %{$opt->{grouptags}}) {
next if $key ne $val;
croak "Bad value in GroupTags: '$key' => '$val'";
}
}
# Check the {variables} option is valid and initialise variables hash
if($opt->{variables} and !UNIVERSAL::isa($opt->{variables}, 'HASH')) {
croak "Illegal value for 'Variables' option - expected a hashref";
}
if($opt->{variables}) {
$self->{_var_values} = { %{$opt->{variables}} };
}
elsif($opt->{varattr}) {
$self->{_var_values} = {};
}
}
##############################################################################
# Method: find_xml_file()
#
# Helper routine for XMLin().
# Takes a filename, and a list of directories, attempts to locate the file in
# the directories listed.
# Returns a full pathname on success; croaks on failure.
#
sub find_xml_file {
my $self = shift;
my $file = shift;
my @search_path = @_;
require File::Basename;
require File::Spec;
my($filename, $filedir) = File::Basename::fileparse($file);
if($filename ne $file) { # Ignore searchpath if dir component
return($file) if(-e $file);
}
else {
my($path);
foreach $path (@search_path) {
my $fullpath = File::Spec->catfile($path, $file);
return($fullpath) if(-e $fullpath);
}
}
# If user did not supply a search path, default to current directory
if(!@search_path) {
return($file) if(-e $file);
croak "File does not exist: $file";
}
croak "Could not find $file in ", join(':', @search_path);
}
##############################################################################
# Method: collapse()
#
# Helper routine for XMLin(). This routine really comprises the 'smarts' (or
# value add) of this module.
#
# Takes the parse tree that XML::Parser produced from the supplied XML and
# recurses through it 'collapsing' unnecessary levels of indirection (nested
# arrays etc) to produce a data structure that is easier to work with.
#
# Elements in the original parser tree are represented as an element name
# followed by an arrayref. The first element of the array is a hashref
# containing the attributes. The rest of the array contains a list of any
# nested elements as name+arrayref pairs:
#
# <element name>, [ { <attribute hashref> }, <element name>, [ ... ], ... ]
#
# The special element name '0' (zero) flags text content.
#
# This routine cuts down the noise by discarding any text content consisting of
# only whitespace and then moves the nested elements into the attribute hash
# using the name of the nested element as the hash key and the collapsed
# version of the nested element as the value. Multiple nested elements with
# the same name will initially be represented as an arrayref, but this may be
# 'folded' into a hashref depending on the value of the keyattr option.
#
sub collapse {
my $self = shift;
# Start with the hash of attributes
my $attr = shift;
if($self->{opt}->{noattr}) { # Discard if 'noattr' set
$attr = {};
}
elsif($self->{opt}->{normalisespace} == 2) {
while(my($key, $value) = each %$attr) {
$attr->{$key} = $self->normalise_space($value)
}
}
# Do variable substitutions
if(my $var = $self->{_var_values}) {
while(my($key, $val) = each(%$attr)) {
$val =~ s{\$\{([\w.]+)\}}{ $self->get_var($1) }ge;
$attr->{$key} = $val;
}
}
# Roll up 'value' attributes (but only if no nested elements)
if(!@_ and keys %$attr == 1) {
my($k) = keys %$attr;
if($self->{opt}->{valueattrlist} and $self->{opt}->{valueattrlist}->{$k}) {
return $attr->{$k};
}
}
# Add any nested elements
my($key, $val);
while(@_) {
$key = shift;
$val = shift;
if(ref($val)) {
$val = $self->collapse(@$val);
next if(!defined($val) and $self->{opt}->{suppressempty});
}
elsif($key eq '0') {
next if($val =~ m{^\s*$}s); # Skip all whitespace content
$val = $self->normalise_space($val)
if($self->{opt}->{normalisespace} == 2);
# do variable substitutions
if(my $var = $self->{_var_values}) {
$val =~ s{\$\{(\w+)\}}{ $self->get_var($1) }ge;
}
# look for variable definitions
if(my $var = $self->{opt}->{varattr}) {
if(exists $attr->{$var}) {
$self->set_var($attr->{$var}, $val);
}
}
# Collapse text content in element with no attributes to a string
if(!%$attr and !@_) {
return($self->{opt}->{forcecontent} ?
{ $self->{opt}->{contentkey} => $val } : $val
);
}
$key = $self->{opt}->{contentkey};
}
# Combine duplicate attributes into arrayref if required
if(exists($attr->{$key})) {
if(UNIVERSAL::isa($attr->{$key}, 'ARRAY')) {
push(@{$attr->{$key}}, $val);
}
else {
$attr->{$key} = [ $attr->{$key}, $val ];
}
}
elsif(defined($val) and UNIVERSAL::isa($val, 'ARRAY')) {
$attr->{$key} = [ $val ];
}
else {
if( $key ne $self->{opt}->{contentkey}
and (
($self->{opt}->{forcearray} == 1)
or (
(ref($self->{opt}->{forcearray}) eq 'HASH')
and (
$self->{opt}->{forcearray}->{$key}
or (grep $key =~ $_, @{$self->{opt}->{forcearray}->{_regex}})
)
)
)
) {
$attr->{$key} = [ $val ];
}
else {
$attr->{$key} = $val;
}
}
}
# Turn arrayrefs into hashrefs if key fields present
if($self->{opt}->{keyattr}) {
while(($key,$val) = each %$attr) {
if(defined($val) and UNIVERSAL::isa($val, 'ARRAY')) {
$attr->{$key} = $self->array_to_hash($key, $val);
}
}
}
# disintermediate grouped tags
if($self->{opt}->{grouptags}) {
while(my($key, $val) = each(%$attr)) {
next unless(UNIVERSAL::isa($val, 'HASH') and (keys %$val == 1));
next unless(exists($self->{opt}->{grouptags}->{$key}));
my($child_key, $child_val) = %$val;
if($self->{opt}->{grouptags}->{$key} eq $child_key) {
$attr->{$key}= $child_val;
}
}
}
# Fold hashes containing a single anonymous array up into just the array
my $count = scalar keys %$attr;
if($count == 1
and exists $attr->{anon}
and UNIVERSAL::isa($attr->{anon}, 'ARRAY')
) {
return($attr->{anon});
}
# Do the right thing if hash is empty, otherwise just return it
if(!%$attr and exists($self->{opt}->{suppressempty})) {
if(defined($self->{opt}->{suppressempty}) and
$self->{opt}->{suppressempty} eq '') {
return('');
}
return(undef);
}
# Roll up named elements with named nested 'value' attributes
if($self->{opt}->{valueattr}) {
while(my($key, $val) = each(%$attr)) {
next unless($self->{opt}->{valueattr}->{$key});
next unless(UNIVERSAL::isa($val, 'HASH') and (keys %$val == 1));
my($k) = keys %$val;
next unless($k eq $self->{opt}->{valueattr}->{$key});
$attr->{$key} = $val->{$k};
}
}
return($attr)
}
##############################################################################
# Method: set_var()
#
# Called when a variable definition is encountered in the XML. (A variable
# definition looks like <element attrname="name">value</element> where attrname
# matches the varattr setting).
#
sub set_var {
my($self, $name, $value) = @_;
$self->{_var_values}->{$name} = $value;
}
##############################################################################
# Method: get_var()
#
# Called during variable substitution to get the value for the named variable.
#
sub get_var {
my($self, $name) = @_;
my $value = $self->{_var_values}->{$name};
return $value if(defined($value));
return '${' . $name . '}';
}
##############################################################################
# Method: normalise_space()
#
# Strips leading and trailing whitespace and collapses sequences of whitespace
# characters to a single space.
#
sub normalise_space {
my($self, $text) = @_;
$text =~ s/^\s+//s;
$text =~ s/\s+$//s;
$text =~ s/\s\s+/ /sg;
return $text;
}
##############################################################################
# Method: array_to_hash()
#
# Helper routine for collapse().
# Attempts to 'fold' an array of hashes into an hash of hashes. Returns a
# reference to the hash on success or the original array if folding is
# not possible. Behaviour is controlled by 'keyattr' option.
#
sub array_to_hash {
my $self = shift;
my $name = shift;
my $arrayref = shift;
my $hashref = $self->new_hashref;
my($i, $key, $val, $flag);
# Handle keyattr => { .... }
if(ref($self->{opt}->{keyattr}) eq 'HASH') {
return($arrayref) unless(exists($self->{opt}->{keyattr}->{$name}));
($key, $flag) = @{$self->{opt}->{keyattr}->{$name}};
for($i = 0; $i < @$arrayref; $i++) {
if(UNIVERSAL::isa($arrayref->[$i], 'HASH') and
exists($arrayref->[$i]->{$key})
) {
$val = $arrayref->[$i]->{$key};
if(ref($val)) {
$self->die_or_warn("<$name> element has non-scalar '$key' key attribute");
return($arrayref);
}
$val = $self->normalise_space($val)
if($self->{opt}->{normalisespace} == 1);
$self->die_or_warn("<$name> element has non-unique value in '$key' key attribute: $val")
if(exists($hashref->{$val}));
$hashref->{$val} = { %{$arrayref->[$i]} };
$hashref->{$val}->{"-$key"} = $hashref->{$val}->{$key} if($flag eq '-');
delete $hashref->{$val}->{$key} unless($flag eq '+');
}
else {
$self->die_or_warn("<$name> element has no '$key' key attribute");
return($arrayref);
}
}
}
# Or assume keyattr => [ .... ]
else {
my $default_keys =
join(',', @DefKeyAttr) eq join(',', @{$self->{opt}->{keyattr}});
ELEMENT: for($i = 0; $i < @$arrayref; $i++) {
return($arrayref) unless(UNIVERSAL::isa($arrayref->[$i], 'HASH'));
foreach $key (@{$self->{opt}->{keyattr}}) {
if(defined($arrayref->[$i]->{$key})) {
$val = $arrayref->[$i]->{$key};
if(ref($val)) {
$self->die_or_warn("<$name> element has non-scalar '$key' key attribute")
if not $default_keys;
return($arrayref);
}
$val = $self->normalise_space($val)
if($self->{opt}->{normalisespace} == 1);
$self->die_or_warn("<$name> element has non-unique value in '$key' key attribute: $val")
if(exists($hashref->{$val}));
$hashref->{$val} = { %{$arrayref->[$i]} };
delete $hashref->{$val}->{$key};
next ELEMENT;
}
}
return($arrayref); # No keyfield matched
}
}
# collapse any hashes which now only have a 'content' key
if($self->{opt}->{collapseagain}) {
$hashref = $self->collapse_content($hashref);
}
return($hashref);
}
##############################################################################
# Method: die_or_warn()
#
# Takes a diagnostic message and does one of three things:
# 1. dies if strict mode is enabled
# 2. warns if warnings are enabled but strict mode is not
# 3. ignores message and resturns silently if neither strict mode nor warnings
# are enabled
#
sub die_or_warn {
my $self = shift;
my $msg = shift;
croak $msg if($StrictMode);
carp "Warning: $msg" if($^W);
}
##############################################################################
# Method: new_hashref()
#
# This is a hook routine for overriding in a sub-class. Some people believe
# that using Tie::IxHash here will solve order-loss problems.
#
sub new_hashref {
my $self = shift;
return { @_ };
}
##############################################################################
# Method: collapse_content()
#
# Helper routine for array_to_hash
#
# Arguments expected are:
# - an XML::Simple object
# - a hasref
# the hashref is a former array, turned into a hash by array_to_hash because
# of the presence of key attributes
# at this point collapse_content avoids over-complicated structures like
# dir => { libexecdir => { content => '$exec_prefix/libexec' },
# localstatedir => { content => '$prefix' },
# }
# into
# dir => { libexecdir => '$exec_prefix/libexec',
# localstatedir => '$prefix',
# }
sub collapse_content {
my $self = shift;
my $hashref = shift;
my $contentkey = $self->{opt}->{contentkey};
# first go through the values,checking that they are fit to collapse
foreach my $val (values %$hashref) {
return $hashref unless ( (ref($val) eq 'HASH')
and (keys %$val == 1)
and (exists $val->{$contentkey})
);
}
# now collapse them
foreach my $key (keys %$hashref) {
$hashref->{$key}= $hashref->{$key}->{$contentkey};
}
return $hashref;
}
##############################################################################
# Method: value_to_xml()
#
# Helper routine for XMLout() - recurses through a data structure building up
# and returning an XML representation of that structure as a string.
#
# Arguments expected are:
# - the data structure to be encoded (usually a reference)
# - the XML tag name to use for this item
# - a string of spaces for use as the current indent level
#
sub value_to_xml {
my $self = shift;;
# Grab the other arguments
my($ref, $name, $indent) = @_;
my $named = (defined($name) and $name ne '' ? 1 : 0);
my $nl = "\n";
my $is_root = $indent eq '' ? 1 : 0; # Warning, dirty hack!
if($self->{opt}->{noindent}) {
$indent = '';
$nl = '';
}
# Convert to XML
if(ref($ref)) {
croak "circular data structures not supported"
if(grep($_ == $ref, @{$self->{_ancestors}}));
push @{$self->{_ancestors}}, $ref;
}
else {
if($named) {
return(join('',
$indent, '<', $name, '>',
($self->{opt}->{noescape} ? $ref : $self->escape_value($ref)),
'</', $name, ">", $nl
));
}
else {
return("$ref$nl");
}
}
# Unfold hash to array if possible
if(UNIVERSAL::isa($ref, 'HASH') # It is a hash
and keys %$ref # and it's not empty
and $self->{opt}->{keyattr} # and folding is enabled
and !$is_root # and its not the root element
) {
$ref = $self->hash_to_array($name, $ref);
}
my @result = ();
my($key, $value);
# Handle hashrefs
if(UNIVERSAL::isa($ref, 'HASH')) {
# Reintermediate grouped values if applicable
if($self->{opt}->{grouptags}) {
$ref = $self->copy_hash($ref);
while(my($key, $val) = each %$ref) {
if($self->{opt}->{grouptags}->{$key}) {
$ref->{$key} = { $self->{opt}->{grouptags}->{$key} => $val };
}
}
}
# Scan for namespace declaration attributes
my $nsdecls = '';
my $default_ns_uri;
if($self->{nsup}) {
$ref = $self->copy_hash($ref);
$self->{nsup}->push_context();
# Look for default namespace declaration first
if(exists($ref->{xmlns})) {
$self->{nsup}->declare_prefix('', $ref->{xmlns});
$nsdecls .= qq( xmlns="$ref->{xmlns}");
delete($ref->{xmlns});
}
$default_ns_uri = $self->{nsup}->get_uri('');
# Then check all the other keys
foreach my $qname (keys(%$ref)) {
my($uri, $lname) = $self->{nsup}->parse_jclark_notation($qname);
if($uri) {
if($uri eq $xmlns_ns) {
$self->{nsup}->declare_prefix($lname, $ref->{$qname});
$nsdecls .= qq( xmlns:$lname="$ref->{$qname}");
delete($ref->{$qname});
}
}
}
# Translate any remaining Clarkian names
foreach my $qname (keys(%$ref)) {
my($uri, $lname) = $self->{nsup}->parse_jclark_notation($qname);
if($uri) {
if($default_ns_uri and $uri eq $default_ns_uri) {
$ref->{$lname} = $ref->{$qname};
delete($ref->{$qname});
}
else {
my $prefix = $self->{nsup}->get_prefix($uri);
unless($prefix) {
# $self->{nsup}->declare_prefix(undef, $uri);
# $prefix = $self->{nsup}->get_prefix($uri);
$prefix = $self->{ns_prefix}++;
$self->{nsup}->declare_prefix($prefix, $uri);
$nsdecls .= qq( xmlns:$prefix="$uri");
}
$ref->{"$prefix:$lname"} = $ref->{$qname};
delete($ref->{$qname});
}
}
}
}
my @nested = ();
my $text_content = undef;
if($named) {
push @result, $indent, '<', $name, $nsdecls;
}
if(keys %$ref) {
my $first_arg = 1;
foreach my $key ($self->sorted_keys($name, $ref)) {
my $value = $ref->{$key};
next if(substr($key, 0, 1) eq '-');
if(!defined($value)) {
next if $self->{opt}->{suppressempty};
unless(exists($self->{opt}->{suppressempty})
and !defined($self->{opt}->{suppressempty})
) {
carp 'Use of uninitialized value' if($^W);
}
if($key eq $self->{opt}->{contentkey}) {
$text_content = '';
}
else {
$value = exists($self->{opt}->{suppressempty}) ? {} : '';
}
}
if(!ref($value)
and $self->{opt}->{valueattr}
and $self->{opt}->{valueattr}->{$key}
) {
$value = { $self->{opt}->{valueattr}->{$key} => $value };
}
if(ref($value) or $self->{opt}->{noattr}) {
push @nested,
$self->value_to_xml($value, $key, "$indent ");
}
else {
$value = $self->escape_value($value) unless($self->{opt}->{noescape});
if($key eq $self->{opt}->{contentkey}) {
$text_content = $value;
}
else {
push @result, "\n$indent " . ' ' x length($name)
if($self->{opt}->{attrindent} and !$first_arg);
push @result, ' ', $key, '="', $value , '"';
$first_arg = 0;
}
}
}
}
else {
$text_content = '';
}
if(@nested or defined($text_content)) {
if($named) {
push @result, ">";
if(defined($text_content)) {
push @result, $text_content;
$nested[0] =~ s/^\s+// if(@nested);
}
else {
push @result, $nl;
}
if(@nested) {
push @result, @nested, $indent;
}
push @result, '</', $name, ">", $nl;
}
else {
push @result, @nested; # Special case if no root elements
}
}
else {
push @result, " />", $nl;
}
$self->{nsup}->pop_context() if($self->{nsup});
}
# Handle arrayrefs
elsif(UNIVERSAL::isa($ref, 'ARRAY')) {
foreach $value (@$ref) {
next if !defined($value) and $self->{opt}->{suppressempty};
if(!ref($value)) {
push @result,
$indent, '<', $name, '>',
($self->{opt}->{noescape} ? $value : $self->escape_value($value)),
'</', $name, ">$nl";
}
elsif(UNIVERSAL::isa($value, 'HASH')) {
push @result, $self->value_to_xml($value, $name, $indent);
}
else {
push @result,
$indent, '<', $name, ">$nl",
$self->value_to_xml($value, 'anon', "$indent "),
$indent, '</', $name, ">$nl";
}
}
}
else {
croak "Can't encode a value of type: " . ref($ref);
}
pop @{$self->{_ancestors}} if(ref($ref));
return(join('', @result));
}
##############################################################################
# Method: sorted_keys()
#
# Returns the keys of the referenced hash sorted into alphabetical order, but
# with the 'key' key (as in KeyAttr) first, if there is one.
#
sub sorted_keys {
my($self, $name, $ref) = @_;
return keys %$ref if $self->{opt}->{nosort};
my %hash = %$ref;
my $keyattr = $self->{opt}->{keyattr};
my @key;
if(ref $keyattr eq 'HASH') {
if(exists $keyattr->{$name} and exists $hash{$keyattr->{$name}->[0]}) {
push @key, $keyattr->{$name}->[0];
delete $hash{$keyattr->{$name}->[0]};
}
}
elsif(ref $keyattr eq 'ARRAY') {
foreach (@{$keyattr}) {
if(exists $hash{$_}) {
push @key, $_;
delete $hash{$_};
last;
}
}
}
return(@key, sort keys %hash);
}
##############################################################################
# Method: escape_value()
#
# Helper routine for automatically escaping values for XMLout().
# Expects a scalar data value. Returns escaped version.
#
sub escape_value {
my($self, $data) = @_;
return '' unless(defined($data));
$data =~ s/&/&amp;/sg;
$data =~ s/</&lt;/sg;
$data =~ s/>/&gt;/sg;
$data =~ s/"/&quot;/sg;
my $level = $self->{opt}->{numericescape} or return $data;
return $self->numeric_escape($data, $level);
}
sub numeric_escape {
my($self, $data, $level) = @_;
use utf8; # required for 5.6
if($self->{opt}->{numericescape} eq '2') {
$data =~ s/([^\x00-\x7F])/'&#' . ord($1) . ';'/gse;
}
else {
$data =~ s/([^\x00-\xFF])/'&#' . ord($1) . ';'/gse;
}
return $data;
}
##############################################################################
# Method: hash_to_array()
#
# Helper routine for value_to_xml().
# Attempts to 'unfold' a hash of hashes into an array of hashes. Returns a
# reference to the array on success or the original hash if unfolding is
# not possible.
#
sub hash_to_array {
my $self = shift;
my $parent = shift;
my $hashref = shift;
my $arrayref = [];
my($key, $value);
my @keys = $self->{opt}->{nosort} ? keys %$hashref : sort keys %$hashref;
foreach $key (@keys) {
$value = $hashref->{$key};
return($hashref) unless(UNIVERSAL::isa($value, 'HASH'));
if(ref($self->{opt}->{keyattr}) eq 'HASH') {
return($hashref) unless(defined($self->{opt}->{keyattr}->{$parent}));
push @$arrayref, $self->copy_hash(
$value, $self->{opt}->{keyattr}->{$parent}->[0] => $key
);
}
else {
push(@$arrayref, { $self->{opt}->{keyattr}->[0] => $key, %$value });
}
}
return($arrayref);
}
##############################################################################
# Method: copy_hash()
#
# Helper routine for hash_to_array(). When unfolding a hash of hashes into
# an array of hashes, we need to copy the key from the outer hash into the
# inner hash. This routine makes a copy of the original hash so we don't
# destroy the original data structure. You might wish to override this
# method if you're using tied hashes and don't want them to get untied.
#
sub copy_hash {
my($self, $orig, @extra) = @_;
return { @extra, %$orig };
}
##############################################################################
# Methods required for building trees from SAX events
##############################################################################
sub start_document {
my $self = shift;
$self->handle_options('in') unless($self->{opt});
$self->{lists} = [];
$self->{curlist} = $self->{tree} = [];
}
sub start_element {
my $self = shift;
my $element = shift;
my $name = $element->{Name};
if($self->{opt}->{nsexpand}) {
$name = $element->{LocalName} || '';
if($element->{NamespaceURI}) {
$name = '{' . $element->{NamespaceURI} . '}' . $name;
}
}
my $attributes = {};
if($element->{Attributes}) { # Might be undef
foreach my $attr (values %{$element->{Attributes}}) {
if($self->{opt}->{nsexpand}) {
my $name = $attr->{LocalName} || '';
if($attr->{NamespaceURI}) {
$name = '{' . $attr->{NamespaceURI} . '}' . $name
}
$name = 'xmlns' if($name eq $bad_def_ns_jcn);
$attributes->{$name} = $attr->{Value};
}
else {
$attributes->{$attr->{Name}} = $attr->{Value};
}
}
}
my $newlist = [ $attributes ];
push @{ $self->{lists} }, $self->{curlist};
push @{ $self->{curlist} }, $name => $newlist;
$self->{curlist} = $newlist;
}
sub characters {
my $self = shift;
my $chars = shift;
my $text = $chars->{Data};
my $clist = $self->{curlist};
my $pos = $#$clist;
if ($pos > 0 and $clist->[$pos - 1] eq '0') {
$clist->[$pos] .= $text;
}
else {
push @$clist, 0 => $text;
}
}
sub end_element {
my $self = shift;
$self->{curlist} = pop @{ $self->{lists} };
}
sub end_document {
my $self = shift;
delete($self->{curlist});
delete($self->{lists});
my $tree = $self->{tree};
delete($self->{tree});
# Return tree as-is to XMLin()
return($tree) if($self->{nocollapse});
# Or collapse it before returning it to SAX parser class
if($self->{opt}->{keeproot}) {
$tree = $self->collapse({}, @$tree);
}
else {
$tree = $self->collapse(@{$tree->[1]});
}
if($self->{opt}->{datahandler}) {
return($self->{opt}->{datahandler}->($self, $tree));
}
return($tree);
}
*xml_in = \&XMLin;
*xml_out = \&XMLout;
1;
__END__
=head1 QUICK START
Say you have a script called B<foo> and a file of configuration options
called B<foo.xml> containing this:
<config logdir="/var/log/foo/" debugfile="/tmp/foo.debug">
<server name="sahara" osname="solaris" osversion="2.6">
<address>10.0.0.101</address>
<address>10.0.1.101</address>
</server>
<server name="gobi" osname="irix" osversion="6.5">
<address>10.0.0.102</address>
</server>
<server name="kalahari" osname="linux" osversion="2.0.34">
<address>10.0.0.103</address>
<address>10.0.1.103</address>
</server>
</config>
The following lines of code in B<foo>:
use XML::Simple;
my $config = XMLin();
will 'slurp' the configuration options into the hashref $config (because no
arguments are passed to C<XMLin()> the name and location of the XML file will
be inferred from name and location of the script). You can dump out the
contents of the hashref using Data::Dumper:
use Data::Dumper;
print Dumper($config);
which will produce something like this (formatting has been adjusted for
brevity):
{
'logdir' => '/var/log/foo/',
'debugfile' => '/tmp/foo.debug',
'server' => {
'sahara' => {
'osversion' => '2.6',
'osname' => 'solaris',
'address' => [ '10.0.0.101', '10.0.1.101' ]
},
'gobi' => {
'osversion' => '6.5',
'osname' => 'irix',
'address' => '10.0.0.102'
},
'kalahari' => {
'osversion' => '2.0.34',
'osname' => 'linux',
'address' => [ '10.0.0.103', '10.0.1.103' ]
}
}
}
Your script could then access the name of the log directory like this:
print $config->{logdir};
similarly, the second address on the server 'kalahari' could be referenced as:
print $config->{server}->{kalahari}->{address}->[1];
What could be simpler? (Rhetorical).
For simple requirements, that's really all there is to it. If you want to
store your XML in a different directory or file, or pass it in as a string or
even pass it in via some derivative of an IO::Handle, you'll need to check out
L<"OPTIONS">. If you want to turn off or tweak the array folding feature (that
neat little transformation that produced $config->{server}) you'll find options
for that as well.
If you want to generate XML (for example to write a modified version of
$config back out as XML), check out C<XMLout()>.
If your needs are not so simple, this may not be the module for you. In that
case, you might want to read L<"WHERE TO FROM HERE?">.
=head1 DESCRIPTION
The XML::Simple module provides a simple API layer on top of an underlying XML
parsing module (either XML::Parser or one of the SAX2 parser modules). Two
functions are exported: C<XMLin()> and C<XMLout()>. Note: you can explicity
request the lower case versions of the function names: C<xml_in()> and
C<xml_out()>.
The simplest approach is to call these two functions directly, but an
optional object oriented interface (see L<"OPTIONAL OO INTERFACE"> below)
allows them to be called as methods of an B<XML::Simple> object. The object
interface can also be used at either end of a SAX pipeline.
=head2 XMLin()
Parses XML formatted data and returns a reference to a data structure which
contains the same information in a more readily accessible form. (Skip
down to L<"EXAMPLES"> below, for more sample code).
C<XMLin()> accepts an optional XML specifier followed by zero or more 'name =>
value' option pairs. The XML specifier can be one of the following:
=over 4
=item A filename
If the filename contains no directory components C<XMLin()> will look for the
file in each directory in the SearchPath (see L<"OPTIONS"> below) or in the
current directory if the SearchPath option is not defined. eg:
$ref = XMLin('/etc/params.xml');
Note, the filename '-' can be used to parse from STDIN.
=item undef
If there is no XML specifier, C<XMLin()> will check the script directory and
each of the SearchPath directories for a file with the same name as the script
but with the extension '.xml'. Note: if you wish to specify options, you
must specify the value 'undef'. eg:
$ref = XMLin(undef, ForceArray => 1);
=item A string of XML
A string containing XML (recognised by the presence of '<' and '>' characters)
will be parsed directly. eg:
$ref = XMLin('<opt username="bob" password="flurp" />');
=item An IO::Handle object
An IO::Handle object will be read to EOF and its contents parsed. eg:
$fh = IO::File->new('/etc/params.xml');
$ref = XMLin($fh);
=back
=head2 XMLout()
Takes a data structure (generally a hashref) and returns an XML encoding of
that structure. If the resulting XML is parsed using C<XMLin()>, it should
return a data structure equivalent to the original (see caveats below).
The C<XMLout()> function can also be used to output the XML as SAX events
see the C<Handler> option and L<"SAX SUPPORT"> for more details).
When translating hashes to XML, hash keys which have a leading '-' will be
silently skipped. This is the approved method for marking elements of a
data structure which should be ignored by C<XMLout>. (Note: If these items
were not skipped the key names would be emitted as element or attribute names
with a leading '-' which would not be valid XML).
=head2 Caveats
Some care is required in creating data structures which will be passed to
C<XMLout()>. Hash keys from the data structure will be encoded as either XML
element names or attribute names. Therefore, you should use hash key names
which conform to the relatively strict XML naming rules:
Names in XML must begin with a letter. The remaining characters may be
letters, digits, hyphens (-), underscores (_) or full stops (.). It is also
allowable to include one colon (:) in an element name but this should only be
used when working with namespaces (B<XML::Simple> can only usefully work with
namespaces when teamed with a SAX Parser).
You can use other punctuation characters in hash values (just not in hash
keys) however B<XML::Simple> does not support dumping binary data.
If you break these rules, the current implementation of C<XMLout()> will
simply emit non-compliant XML which will be rejected if you try to read it
back in. (A later version of B<XML::Simple> might take a more proactive
approach).
Note also that although you can nest hashes and arrays to arbitrary levels,
circular data structures are not supported and will cause C<XMLout()> to die.
If you wish to 'round-trip' arbitrary data structures from Perl to XML and back
to Perl, then you should probably disable array folding (using the KeyAttr
option) both with C<XMLout()> and with C<XMLin()>. If you still don't get the
expected results, you may prefer to use L<XML::Dumper> which is designed for
exactly that purpose.
Refer to L<"WHERE TO FROM HERE?"> if C<XMLout()> is too simple for your needs.
=head1 OPTIONS
B<XML::Simple> supports a number of options (in fact as each release of
B<XML::Simple> adds more options, the module's claim to the name 'Simple'
becomes increasingly tenuous). If you find yourself repeatedly having to
specify the same options, you might like to investigate L<"OPTIONAL OO
INTERFACE"> below.
If you can't be bothered reading the documentation, refer to
L<"STRICT MODE"> to automatically catch common mistakes.
Because there are so many options, it's hard for new users to know which ones
are important, so here are the two you really need to know about:
=over 4
=item *
check out C<ForceArray> because you'll almost certainly want to turn it on
=item *
make sure you know what the C<KeyAttr> option does and what its default value is
because it may surprise you otherwise (note in particular that 'KeyAttr'
affects both C<XMLin> and C<XMLout>)
=back
The option name headings below have a trailing 'comment' - a hash followed by
two pieces of metadata:
=over 4
=item *
Options are marked with 'I<in>' if they are recognised by C<XMLin()> and
'I<out>' if they are recognised by C<XMLout()>.
=item *
Each option is also flagged to indicate whether it is:
'important' - don't use the module until you understand this one
'handy' - you can skip this on the first time through
'advanced' - you can skip this on the second time through
'SAX only' - don't worry about this unless you're using SAX (or
alternatively if you need this, you also need SAX)
'seldom used' - you'll probably never use this unless you were the
person that requested the feature
=back
The options are listed alphabetically:
Note: option names are no longer case sensitive so you can use the mixed case
versions shown here; all lower case as required by versions 2.03 and earlier;
or you can add underscores between the words (eg: key_attr).
=head2 AttrIndent => 1 I<# out - handy>
When you are using C<XMLout()>, enable this option to have attributes printed
one-per-line with sensible indentation rather than all on one line.
=head2 Cache => [ cache schemes ] I<# in - advanced>
Because loading the B<XML::Parser> module and parsing an XML file can consume a
significant number of CPU cycles, it is often desirable to cache the output of
C<XMLin()> for later reuse.
When parsing from a named file, B<XML::Simple> supports a number of caching
schemes. The 'Cache' option may be used to specify one or more schemes (using
an anonymous array). Each scheme will be tried in turn in the hope of finding
a cached pre-parsed representation of the XML file. If no cached copy is
found, the file will be parsed and the first cache scheme in the list will be
used to save a copy of the results. The following cache schemes have been
implemented:
=over 4
=item storable
Utilises B<Storable.pm> to read/write a cache file with the same name as the
XML file but with the extension .stor
=item memshare
When a file is first parsed, a copy of the resulting data structure is retained
in memory in the B<XML::Simple> module's namespace. Subsequent calls to parse
the same file will return a reference to this structure. This cached version
will persist only for the life of the Perl interpreter (which in the case of
mod_perl for example, may be some significant time).
Because each caller receives a reference to the same data structure, a change
made by one caller will be visible to all. For this reason, the reference
returned should be treated as read-only.
=item memcopy
This scheme works identically to 'memshare' (above) except that each caller
receives a reference to a new data structure which is a copy of the cached
version. Copying the data structure will add a little processing overhead,
therefore this scheme should only be used where the caller intends to modify
the data structure (or wishes to protect itself from others who might). This
scheme uses B<Storable.pm> to perform the copy.
=back
Warning! The memory-based caching schemes compare the timestamp on the file to
the time when it was last parsed. If the file is stored on an NFS filesystem
(or other network share) and the clock on the file server is not exactly
synchronised with the clock where your script is run, updates to the source XML
file may appear to be ignored.
=head2 ContentKey => 'keyname' I<# in+out - seldom used>
When text content is parsed to a hash value, this option let's you specify a
name for the hash key to override the default 'content'. So for example:
XMLin('<opt one="1">Text</opt>', ContentKey => 'text')
will parse to:
{ 'one' => 1, 'text' => 'Text' }
instead of:
{ 'one' => 1, 'content' => 'Text' }
C<XMLout()> will also honour the value of this option when converting a hashref
to XML.
You can also prefix your selected key name with a '-' character to have
C<XMLin()> try a little harder to eliminate unnecessary 'content' keys after
array folding. For example:
XMLin(
'<opt><item name="one">First</item><item name="two">Second</item></opt>',
KeyAttr => {item => 'name'},
ForceArray => [ 'item' ],
ContentKey => '-content'
)
will parse to:
{
'item' => {
'one' => 'First'
'two' => 'Second'
}
}
rather than this (without the '-'):
{
'item' => {
'one' => { 'content' => 'First' }
'two' => { 'content' => 'Second' }
}
}
=head2 DataHandler => code_ref I<# in - SAX only>
When you use an B<XML::Simple> object as a SAX handler, it will return a
'simple tree' data structure in the same format as C<XMLin()> would return. If
this option is set (to a subroutine reference), then when the tree is built the
subroutine will be called and passed two arguments: a reference to the
B<XML::Simple> object and a reference to the data tree. The return value from
the subroutine will be returned to the SAX driver. (See L<"SAX SUPPORT"> for
more details).
=head2 ForceArray => 1 I<# in - important>
This option should be set to '1' to force nested elements to be represented
as arrays even when there is only one. Eg, with ForceArray enabled, this
XML:
<opt>
<name>value</name>
</opt>
would parse to this:
{
'name' => [
'value'
]
}
instead of this (the default):
{
'name' => 'value'
}
This option is especially useful if the data structure is likely to be written
back out as XML and the default behaviour of rolling single nested elements up
into attributes is not desirable.
If you are using the array folding feature, you should almost certainly enable
this option. If you do not, single nested elements will not be parsed to
arrays and therefore will not be candidates for folding to a hash. (Given that
the default value of 'KeyAttr' enables array folding, the default value of this
option should probably also have been enabled too - sorry).
=head2 ForceArray => [ names ] I<# in - important>
This alternative (and preferred) form of the 'ForceArray' option allows you to
specify a list of element names which should always be forced into an array
representation, rather than the 'all or nothing' approach above.
It is also possible (since version 2.05) to include compiled regular
expressions in the list - any element names which match the pattern will be
forced to arrays. If the list contains only a single regex, then it is not
necessary to enclose it in an arrayref. Eg:
ForceArray => qr/_list$/
=head2 ForceContent => 1 I<# in - seldom used>
When C<XMLin()> parses elements which have text content as well as attributes,
the text content must be represented as a hash value rather than a simple
scalar. This option allows you to force text content to always parse to
a hash value even when there are no attributes. So for example:
XMLin('<opt><x>text1</x><y a="2">text2</y></opt>', ForceContent => 1)
will parse to:
{
'x' => { 'content' => 'text1' },
'y' => { 'a' => 2, 'content' => 'text2' }
}
instead of:
{
'x' => 'text1',
'y' => { 'a' => 2, 'content' => 'text2' }
}
=head2 GroupTags => { grouping tag => grouped tag } I<# in+out - handy>
You can use this option to eliminate extra levels of indirection in your Perl
data structure. For example this XML:
<opt>
<searchpath>
<dir>/usr/bin</dir>
<dir>/usr/local/bin</dir>
<dir>/usr/X11/bin</dir>
</searchpath>
</opt>
Would normally be read into a structure like this:
{
searchpath => {
dir => [ '/usr/bin', '/usr/local/bin', '/usr/X11/bin' ]
}
}
But when read in with the appropriate value for 'GroupTags':
my $opt = XMLin($xml, GroupTags => { searchpath => 'dir' });
It will return this simpler structure:
{
searchpath => [ '/usr/bin', '/usr/local/bin', '/usr/X11/bin' ]
}
The grouping element (C<< <searchpath> >> in the example) must not contain any
attributes or elements other than the grouped element.
You can specify multiple 'grouping element' to 'grouped element' mappings in
the same hashref. If this option is combined with C<KeyAttr>, the array
folding will occur first and then the grouped element names will be eliminated.
C<XMLout> will also use the grouptag mappings to re-introduce the tags around
the grouped elements. Beware though that this will occur in all places that
the 'grouping tag' name occurs - you probably don't want to use the same name
for elements as well as attributes.
=head2 Handler => object_ref I<# out - SAX only>
Use the 'Handler' option to have C<XMLout()> generate SAX events rather than
returning a string of XML. For more details see L<"SAX SUPPORT"> below.
Note: the current implementation of this option generates a string of XML
and uses a SAX parser to translate it into SAX events. The normal encoding
rules apply here - your data must be UTF8 encoded unless you specify an
alternative encoding via the 'XMLDecl' option; and by the time the data reaches
the handler object, it will be in UTF8 form regardless of the encoding you
supply. A future implementation of this option may generate the events
directly.
=head2 KeepRoot => 1 I<# in+out - handy>
In its attempt to return a data structure free of superfluous detail and
unnecessary levels of indirection, C<XMLin()> normally discards the root
element name. Setting the 'KeepRoot' option to '1' will cause the root element
name to be retained. So after executing this code:
$config = XMLin('<config tempdir="/tmp" />', KeepRoot => 1)
You'll be able to reference the tempdir as
C<$config-E<gt>{config}-E<gt>{tempdir}> instead of the default
C<$config-E<gt>{tempdir}>.
Similarly, setting the 'KeepRoot' option to '1' will tell C<XMLout()> that the
data structure already contains a root element name and it is not necessary to
add another.
=head2 KeyAttr => [ list ] I<# in+out - important>
This option controls the 'array folding' feature which translates nested
elements from an array to a hash. It also controls the 'unfolding' of hashes
to arrays.
For example, this XML:
<opt>
<user login="grep" fullname="Gary R Epstein" />
<user login="stty" fullname="Simon T Tyson" />
</opt>
would, by default, parse to this:
{
'user' => [
{
'login' => 'grep',
'fullname' => 'Gary R Epstein'
},
{
'login' => 'stty',
'fullname' => 'Simon T Tyson'
}
]
}
If the option 'KeyAttr => "login"' were used to specify that the 'login'
attribute is a key, the same XML would parse to:
{
'user' => {
'stty' => {
'fullname' => 'Simon T Tyson'
},
'grep' => {
'fullname' => 'Gary R Epstein'
}
}
}
The key attribute names should be supplied in an arrayref if there is more
than one. C<XMLin()> will attempt to match attribute names in the order
supplied. C<XMLout()> will use the first attribute name supplied when
'unfolding' a hash into an array.
Note 1: The default value for 'KeyAttr' is ['name', 'key', 'id']. If you do
not want folding on input or unfolding on output you must setting this option
to an empty list to disable the feature.
Note 2: If you wish to use this option, you should also enable the
C<ForceArray> option. Without 'ForceArray', a single nested element will be
rolled up into a scalar rather than an array and therefore will not be folded
(since only arrays get folded).
=head2 KeyAttr => { list } I<# in+out - important>
This alternative (and preferred) method of specifiying the key attributes
allows more fine grained control over which elements are folded and on which
attributes. For example the option 'KeyAttr => { package => 'id' } will cause
any package elements to be folded on the 'id' attribute. No other elements
which have an 'id' attribute will be folded at all.
Note: C<XMLin()> will generate a warning (or a fatal error in L<"STRICT MODE">)
if this syntax is used and an element which does not have the specified key
attribute is encountered (eg: a 'package' element without an 'id' attribute, to
use the example above). Warnings will only be generated if B<-w> is in force.
Two further variations are made possible by prefixing a '+' or a '-' character
to the attribute name:
The option 'KeyAttr => { user => "+login" }' will cause this XML:
<opt>
<user login="grep" fullname="Gary R Epstein" />
<user login="stty" fullname="Simon T Tyson" />
</opt>
to parse to this data structure:
{
'user' => {
'stty' => {
'fullname' => 'Simon T Tyson',
'login' => 'stty'
},
'grep' => {
'fullname' => 'Gary R Epstein',
'login' => 'grep'
}
}
}
The '+' indicates that the value of the key attribute should be copied rather
than moved to the folded hash key.
A '-' prefix would produce this result:
{
'user' => {
'stty' => {
'fullname' => 'Simon T Tyson',
'-login' => 'stty'
},
'grep' => {
'fullname' => 'Gary R Epstein',
'-login' => 'grep'
}
}
}
As described earlier, C<XMLout> will ignore hash keys starting with a '-'.
=head2 NoAttr => 1 I<# in+out - handy>
When used with C<XMLout()>, the generated XML will contain no attributes.
All hash key/values will be represented as nested elements instead.
When used with C<XMLin()>, any attributes in the XML will be ignored.
=head2 NoEscape => 1 I<# out - seldom used>
By default, C<XMLout()> will translate the characters 'E<lt>', 'E<gt>', '&' and
'"' to '&lt;', '&gt;', '&amp;' and '&quot' respectively. Use this option to
suppress escaping (presumably because you've already escaped the data in some
more sophisticated manner).
=head2 NoIndent => 1 I<# out - seldom used>
Set this option to 1 to disable C<XMLout()>'s default 'pretty printing' mode.
With this option enabled, the XML output will all be on one line (unless there
are newlines in the data) - this may be easier for downstream processing.
=head2 NoSort => 1 I<# out - seldom used>
Newer versions of XML::Simple sort elements and attributes alphabetically (*),
by default. Enable this option to suppress the sorting - possibly for
backwards compatibility.
* Actually, sorting is alphabetical but 'key' attribute or element names (as in
'KeyAttr') sort first. Also, when a hash of hashes is 'unfolded', the elements
are sorted alphabetically by the value of the key field.
=head2 NormaliseSpace => 0 | 1 | 2 I<# in - handy>
This option controls how whitespace in text content is handled. Recognised
values for the option are:
=over 4
=item *
0 = (default) whitespace is passed through unaltered (except of course for the
normalisation of whitespace in attribute values which is mandated by the XML
recommendation)
=item *
1 = whitespace is normalised in any value used as a hash key (normalising means
removing leading and trailing whitespace and collapsing sequences of whitespace
characters to a single space)
=item *
2 = whitespace is normalised in all text content
=back
Note: you can spell this option with a 'z' if that is more natural for you.
=head2 NSExpand => 1 I<# in+out handy - SAX only>
This option controls namespace expansion - the translation of element and
attribute names of the form 'prefix:name' to '{uri}name'. For example the
element name 'xsl:template' might be expanded to:
'{http://www.w3.org/1999/XSL/Transform}template'.
By default, C<XMLin()> will return element names and attribute names exactly as
they appear in the XML. Setting this option to 1 will cause all element and
attribute names to be expanded to include their namespace prefix.
I<Note: You must be using a SAX parser for this option to work (ie: it does not
work with XML::Parser)>.
This option also controls whether C<XMLout()> performs the reverse translation
from '{uri}name' back to 'prefix:name'. The default is no translation. If
your data contains expanded names, you should set this option to 1 otherwise
C<XMLout> will emit XML which is not well formed.
I<Note: You must have the XML::NamespaceSupport module installed if you want
C<XMLout()> to translate URIs back to prefixes>.
=head2 NumericEscape => 0 | 1 | 2 I<# out - handy>
Use this option to have 'high' (non-ASCII) characters in your Perl data
structure converted to numeric entities (eg: &#8364;) in the XML output. Three
levels are possible:
0 - default: no numeric escaping (OK if you're writing out UTF8)
1 - only characters above 0xFF are escaped (ie: characters in the 0x80-FF range are not escaped), possibly useful with ISO8859-1 output
2 - all characters above 0x7F are escaped (good for plain ASCII output)
=head2 OutputFile => <file specifier> I<# out - handy>
The default behaviour of C<XMLout()> is to return the XML as a string. If you
wish to write the XML to a file, simply supply the filename using the
'OutputFile' option.
This option also accepts an IO handle object - especially useful in Perl 5.8.0
and later for output using an encoding other than UTF-8, eg:
open my $fh, '>:encoding(iso-8859-1)', $path or die "open($path): $!";
XMLout($ref, OutputFile => $fh);
Note, XML::Simple does not require that the object you pass in to the
OutputFile option inherits from L<IO::Handle> - it simply assumes the object
supports a C<print> method.
=head2 ParserOpts => [ XML::Parser Options ] I<# in - don't use this>
I<Note: This option is now officially deprecated. If you find it useful, email
the author with an example of what you use it for. Do not use this option to
set the ProtocolEncoding, that's just plain wrong - fix the XML>.
This option allows you to pass parameters to the constructor of the underlying
XML::Parser object (which of course assumes you're not using SAX).
=head2 RootName => 'string' I<# out - handy>
By default, when C<XMLout()> generates XML, the root element will be named
'opt'. This option allows you to specify an alternative name.
Specifying either undef or the empty string for the RootName option will
produce XML with no root elements. In most cases the resulting XML fragment
will not be 'well formed' and therefore could not be read back in by C<XMLin()>.
Nevertheless, the option has been found to be useful in certain circumstances.
=head2 SearchPath => [ list ] I<# in - handy>
If you pass C<XMLin()> a filename, but the filename include no directory
component, you can use this option to specify which directories should be
searched to locate the file. You might use this option to search first in the
user's home directory, then in a global directory such as /etc.
If a filename is provided to C<XMLin()> but SearchPath is not defined, the
file is assumed to be in the current directory.
If the first parameter to C<XMLin()> is undefined, the default SearchPath
will contain only the directory in which the script itself is located.
Otherwise the default SearchPath will be empty.
=head2 SuppressEmpty => 1 | '' | undef I<# in+out - handy>
This option controls what C<XMLin()> should do with empty elements (no
attributes and no content). The default behaviour is to represent them as
empty hashes. Setting this option to a true value (eg: 1) will cause empty
elements to be skipped altogether. Setting the option to 'undef' or the empty
string will cause empty elements to be represented as the undefined value or
the empty string respectively. The latter two alternatives are a little
easier to test for in your code than a hash with no keys.
The option also controls what C<XMLout()> does with undefined values. Setting
the option to undef causes undefined values to be output as empty elements
(rather than empty attributes), it also suppresses the generation of warnings
about undefined values. Setting the option to a true value (eg: 1) causes
undefined values to be skipped altogether on output.
=head2 ValueAttr => [ names ] I<# in - handy>
Use this option to deal elements which always have a single attribute and no
content. Eg:
<opt>
<colour value="red" />
<size value="XXL" />
</opt>
Setting C<< ValueAttr => [ 'value' ] >> will cause the above XML to parse to:
{
colour => 'red',
size => 'XXL'
}
instead of this (the default):
{
colour => { value => 'red' },
size => { value => 'XXL' }
}
Note: This form of the ValueAttr option is not compatible with C<XMLout()> -
since the attribute name is discarded at parse time, the original XML cannot be
reconstructed.
=head2 ValueAttr => { element => attribute, ... } I<# in+out - handy>
This (preferred) form of the ValueAttr option requires you to specify both
the element and the attribute names. This is not only safer, it also allows
the original XML to be reconstructed by C<XMLout()>.
Note: You probably don't want to use this option and the NoAttr option at the
same time.
=head2 Variables => { name => value } I<# in - handy>
This option allows variables in the XML to be expanded when the file is read.
(there is no facility for putting the variable names back if you regenerate
XML using C<XMLout>).
A 'variable' is any text of the form C<${name}> which occurs in an attribute
value or in the text content of an element. If 'name' matches a key in the
supplied hashref, C<${name}> will be replaced with the corresponding value from
the hashref. If no matching key is found, the variable will not be replaced.
Names must match the regex: C<[\w.]+> (ie: only 'word' characters and dots are
allowed).
=head2 VarAttr => 'attr_name' I<# in - handy>
In addition to the variables defined using C<Variables>, this option allows
variables to be defined in the XML. A variable definition consists of an
element with an attribute called 'attr_name' (the value of the C<VarAttr>
option). The value of the attribute will be used as the variable name and the
text content of the element will be used as the value. A variable defined in
this way will override a variable defined using the C<Variables> option. For
example:
XMLin( '<opt>
<dir name="prefix">/usr/local/apache</dir>
<dir name="exec_prefix">${prefix}</dir>
<dir name="bindir">${exec_prefix}/bin</dir>
</opt>',
VarAttr => 'name', ContentKey => '-content'
);
produces the following data structure:
{
dir => {
prefix => '/usr/local/apache',
exec_prefix => '/usr/local/apache',
bindir => '/usr/local/apache/bin',
}
}
=head2 XMLDecl => 1 or XMLDecl => 'string' I<# out - handy>
If you want the output from C<XMLout()> to start with the optional XML
declaration, simply set the option to '1'. The default XML declaration is:
<?xml version='1.0' standalone='yes'?>
If you want some other string (for example to declare an encoding value), set
the value of this option to the complete string you require.
=head1 OPTIONAL OO INTERFACE
The procedural interface is both simple and convenient however there are a
couple of reasons why you might prefer to use the object oriented (OO)
interface:
=over 4
=item *
to define a set of default values which should be used on all subsequent calls
to C<XMLin()> or C<XMLout()>
=item *
to override methods in B<XML::Simple> to provide customised behaviour
=back
The default values for the options described above are unlikely to suit
everyone. The OO interface allows you to effectively override B<XML::Simple>'s
defaults with your preferred values. It works like this:
First create an XML::Simple parser object with your preferred defaults:
my $xs = XML::Simple->new(ForceArray => 1, KeepRoot => 1);
then call C<XMLin()> or C<XMLout()> as a method of that object:
my $ref = $xs->XMLin($xml);
my $xml = $xs->XMLout($ref);
You can also specify options when you make the method calls and these values
will be merged with the values specified when the object was created. Values
specified in a method call take precedence.
Note: when called as methods, the C<XMLin()> and C<XMLout()> routines may be
called as C<xml_in()> or C<xml_out()>. The method names are aliased so the
only difference is the aesthetics.
=head2 Parsing Methods
You can explicitly call one of the following methods rather than rely on the
C<xml_in()> method automatically determining whether the target to be parsed is
a string, a file or a filehandle:
=over 4
=item parse_string(text)
Works exactly like the C<xml_in()> method but assumes the first argument is
a string of XML (or a reference to a scalar containing a string of XML).
=item parse_file(filename)
Works exactly like the C<xml_in()> method but assumes the first argument is
the name of a file containing XML.
=item parse_fh(file_handle)
Works exactly like the C<xml_in()> method but assumes the first argument is
a filehandle which can be read to get XML.
=back
=head2 Hook Methods
You can make your own class which inherits from XML::Simple and overrides
certain behaviours. The following methods may provide useful 'hooks' upon
which to hang your modified behaviour. You may find other undocumented methods
by examining the source, but those may be subject to change in future releases.
=over 4
=item handle_options(direction, name => value ...)
This method will be called when one of the parsing methods or the C<XMLout()>
method is called. The initial argument will be a string (either 'in' or 'out')
and the remaining arguments will be name value pairs.
=item default_config_file()
Calculates and returns the name of the file which should be parsed if no
filename is passed to C<XMLin()> (default: C<$0.xml>).
=item build_simple_tree(filename, string)
Called from C<XMLin()> or any of the parsing methods. Takes either a file name
as the first argument or C<undef> followed by a 'string' as the second
argument. Returns a simple tree data structure. You could override this
method to apply your own transformations before the data structure is returned
to the caller.
=item new_hashref()
When the 'simple tree' data structure is being built, this method will be
called to create any required anonymous hashrefs.
=item sorted_keys(name, hashref)
Called when C<XMLout()> is translating a hashref to XML. This routine returns
a list of hash keys in the order that the corresponding attributes/elements
should appear in the output.
=item escape_value(string)
Called from C<XMLout()>, takes a string and returns a copy of the string with
XML character escaping rules applied.
=item numeric_escape(string)
Called from C<escape_value()>, to handle non-ASCII characters (depending on the
value of the NumericEscape option).
=item copy_hash(hashref, extra_key => value, ...)
Called from C<XMLout()>, when 'unfolding' a hash of hashes into an array of
hashes. You might wish to override this method if you're using tied hashes and
don't want them to get untied.
=back
=head2 Cache Methods
XML::Simple implements three caching schemes ('storable', 'memshare' and
'memcopy'). You can implement a custom caching scheme by implementing
two methods - one for reading from the cache and one for writing to it.
For example, you might implement a new 'dbm' scheme that stores cached data
structures using the L<MLDBM> module. First, you would add a
C<cache_read_dbm()> method which accepted a filename for use as a lookup key
and returned a data structure on success, or undef on failure. Then, you would
implement a C<cache_read_dbm()> method which accepted a data structure and a
filename.
You would use this caching scheme by specifying the option:
Cache => [ 'dbm' ]
=head1 STRICT MODE
If you import the B<XML::Simple> routines like this:
use XML::Simple qw(:strict);
the following common mistakes will be detected and treated as fatal errors
=over 4
=item *
Failing to explicitly set the C<KeyAttr> option - if you can't be bothered
reading about this option, turn it off with: KeyAttr => [ ]
=item *
Failing to explicitly set the C<ForceArray> option - if you can't be bothered
reading about this option, set it to the safest mode with: ForceArray => 1
=item *
Setting ForceArray to an array, but failing to list all the elements from the
KeyAttr hash.
=item *
Data error - KeyAttr is set to say { part => 'partnum' } but the XML contains
one or more E<lt>partE<gt> elements without a 'partnum' attribute (or nested
element). Note: if strict mode is not set but -w is, this condition triggers a
warning.
=item *
Data error - as above, but non-unique values are present in the key attribute
(eg: more than one E<lt>partE<gt> element with the same partnum). This will
also trigger a warning if strict mode is not enabled.
=item *
Data error - as above, but value of key attribute (eg: partnum) is not a
scalar string (due to nested elements etc). This will also trigger a warning
if strict mode is not enabled.
=back
=head1 SAX SUPPORT
From version 1.08_01, B<XML::Simple> includes support for SAX (the Simple API
for XML) - specifically SAX2.
In a typical SAX application, an XML parser (or SAX 'driver') module generates
SAX events (start of element, character data, end of element, etc) as it parses
an XML document and a 'handler' module processes the events to extract the
required data. This simple model allows for some interesting and powerful
possibilities:
=over 4
=item *
Applications written to the SAX API can extract data from huge XML documents
without the memory overheads of a DOM or tree API.
=item *
The SAX API allows for plug and play interchange of parser modules without
having to change your code to fit a new module's API. A number of SAX parsers
are available with capabilities ranging from extreme portability to blazing
performance.
=item *
A SAX 'filter' module can implement both a handler interface for receiving
data and a generator interface for passing modified data on to a downstream
handler. Filters can be chained together in 'pipelines'.
=item *
One filter module might split a data stream to direct data to two or more
downstream handlers.
=item *
Generating SAX events is not the exclusive preserve of XML parsing modules.
For example, a module might extract data from a relational database using DBI
and pass it on to a SAX pipeline for filtering and formatting.
=back
B<XML::Simple> can operate at either end of a SAX pipeline. For example,
you can take a data structure in the form of a hashref and pass it into a
SAX pipeline using the 'Handler' option on C<XMLout()>:
use XML::Simple;
use Some::SAX::Filter;
use XML::SAX::Writer;
my $ref = {
.... # your data here
};
my $writer = XML::SAX::Writer->new();
my $filter = Some::SAX::Filter->new(Handler => $writer);
my $simple = XML::Simple->new(Handler => $filter);
$simple->XMLout($ref);
You can also put B<XML::Simple> at the opposite end of the pipeline to take
advantage of the simple 'tree' data structure once the relevant data has been
isolated through filtering:
use XML::SAX;
use Some::SAX::Filter;
use XML::Simple;
my $simple = XML::Simple->new(ForceArray => 1, KeyAttr => ['partnum']);
my $filter = Some::SAX::Filter->new(Handler => $simple);
my $parser = XML::SAX::ParserFactory->parser(Handler => $filter);
my $ref = $parser->parse_uri('some_huge_file.xml');
print $ref->{part}->{'555-1234'};
You can build a filter by using an XML::Simple object as a handler and setting
its DataHandler option to point to a routine which takes the resulting tree,
modifies it and sends it off as SAX events to a downstream handler:
my $writer = XML::SAX::Writer->new();
my $filter = XML::Simple->new(
DataHandler => sub {
my $simple = shift;
my $data = shift;
# Modify $data here
$simple->XMLout($data, Handler => $writer);
}
);
my $parser = XML::SAX::ParserFactory->parser(Handler => $filter);
$parser->parse_uri($filename);
I<Note: In this last example, the 'Handler' option was specified in the call to
C<XMLout()> but it could also have been specified in the constructor>.
=head1 ENVIRONMENT
If you don't care which parser module B<XML::Simple> uses then skip this
section entirely (it looks more complicated than it really is).
B<XML::Simple> will default to using a B<SAX> parser if one is available or
B<XML::Parser> if SAX is not available.
You can dictate which parser module is used by setting either the environment
variable 'XML_SIMPLE_PREFERRED_PARSER' or the package variable
$XML::Simple::PREFERRED_PARSER to contain the module name. The following rules
are used:
=over 4
=item *
The package variable takes precedence over the environment variable if both are defined. To force B<XML::Simple> to ignore the environment settings and use
its default rules, you can set the package variable to an empty string.
=item *
If the 'preferred parser' is set to the string 'XML::Parser', then
L<XML::Parser> will be used (or C<XMLin()> will die if L<XML::Parser> is not
installed).
=item *
If the 'preferred parser' is set to some other value, then it is assumed to be
the name of a SAX parser module and is passed to L<XML::SAX::ParserFactory.>
If L<XML::SAX> is not installed, or the requested parser module is not
installed, then C<XMLin()> will die.
=item *
If the 'preferred parser' is not defined at all (the normal default
state), an attempt will be made to load L<XML::SAX>. If L<XML::SAX> is
installed, then a parser module will be selected according to
L<XML::SAX::ParserFactory>'s normal rules (which typically means the last SAX
parser installed).
=item *
if the 'preferred parser' is not defined and B<XML::SAX> is not
installed, then B<XML::Parser> will be used. C<XMLin()> will die if
L<XML::Parser> is not installed.
=back
Note: The B<XML::SAX> distribution includes an XML parser written entirely in
Perl. It is very portable but it is not very fast. You should consider
installing L<XML::LibXML> or L<XML::SAX::Expat> if they are available for your
platform.
=head1 ERROR HANDLING
The XML standard is very clear on the issue of non-compliant documents. An
error in parsing any single element (for example a missing end tag) must cause
the whole document to be rejected. B<XML::Simple> will die with an appropriate
message if it encounters a parsing error.
If dying is not appropriate for your application, you should arrange to call
C<XMLin()> in an eval block and look for errors in $@. eg:
my $config = eval { XMLin() };
PopUpMessage($@) if($@);
Note, there is a common misconception that use of B<eval> will significantly
slow down a script. While that may be true when the code being eval'd is in a
string, it is not true of code like the sample above.
=head1 EXAMPLES
When C<XMLin()> reads the following very simple piece of XML:
<opt username="testuser" password="frodo"></opt>
it returns the following data structure:
{
'username' => 'testuser',
'password' => 'frodo'
}
The identical result could have been produced with this alternative XML:
<opt username="testuser" password="frodo" />
Or this (although see 'ForceArray' option for variations):
<opt>
<username>testuser</username>
<password>frodo</password>
</opt>
Repeated nested elements are represented as anonymous arrays:
<opt>
<person firstname="Joe" lastname="Smith">
<email>joe@smith.com</email>
<email>jsmith@yahoo.com</email>
</person>
<person firstname="Bob" lastname="Smith">
<email>bob@smith.com</email>
</person>
</opt>
{
'person' => [
{
'email' => [
'joe@smith.com',
'jsmith@yahoo.com'
],
'firstname' => 'Joe',
'lastname' => 'Smith'
},
{
'email' => 'bob@smith.com',
'firstname' => 'Bob',
'lastname' => 'Smith'
}
]
}
Nested elements with a recognised key attribute are transformed (folded) from
an array into a hash keyed on the value of that attribute (see the C<KeyAttr>
option):
<opt>
<person key="jsmith" firstname="Joe" lastname="Smith" />
<person key="tsmith" firstname="Tom" lastname="Smith" />
<person key="jbloggs" firstname="Joe" lastname="Bloggs" />
</opt>
{
'person' => {
'jbloggs' => {
'firstname' => 'Joe',
'lastname' => 'Bloggs'
},
'tsmith' => {
'firstname' => 'Tom',
'lastname' => 'Smith'
},
'jsmith' => {
'firstname' => 'Joe',
'lastname' => 'Smith'
}
}
}
The <anon> tag can be used to form anonymous arrays:
<opt>
<head><anon>Col 1</anon><anon>Col 2</anon><anon>Col 3</anon></head>
<data><anon>R1C1</anon><anon>R1C2</anon><anon>R1C3</anon></data>
<data><anon>R2C1</anon><anon>R2C2</anon><anon>R2C3</anon></data>
<data><anon>R3C1</anon><anon>R3C2</anon><anon>R3C3</anon></data>
</opt>
{
'head' => [
[ 'Col 1', 'Col 2', 'Col 3' ]
],
'data' => [
[ 'R1C1', 'R1C2', 'R1C3' ],
[ 'R2C1', 'R2C2', 'R2C3' ],
[ 'R3C1', 'R3C2', 'R3C3' ]
]
}
Anonymous arrays can be nested to arbirtrary levels and as a special case, if
the surrounding tags for an XML document contain only an anonymous array the
arrayref will be returned directly rather than the usual hashref:
<opt>
<anon><anon>Col 1</anon><anon>Col 2</anon></anon>
<anon><anon>R1C1</anon><anon>R1C2</anon></anon>
<anon><anon>R2C1</anon><anon>R2C2</anon></anon>
</opt>
[
[ 'Col 1', 'Col 2' ],
[ 'R1C1', 'R1C2' ],
[ 'R2C1', 'R2C2' ]
]
Elements which only contain text content will simply be represented as a
scalar. Where an element has both attributes and text content, the element
will be represented as a hashref with the text content in the 'content' key
(see the C<ContentKey> option):
<opt>
<one>first</one>
<two attr="value">second</two>
</opt>
{
'one' => 'first',
'two' => { 'attr' => 'value', 'content' => 'second' }
}
Mixed content (elements which contain both text content and nested elements)
will be not be represented in a useful way - element order and significant
whitespace will be lost. If you need to work with mixed content, then
XML::Simple is not the right tool for your job - check out the next section.
=head1 WHERE TO FROM HERE?
B<XML::Simple> is able to present a simple API because it makes some
assumptions on your behalf. These include:
=over 4
=item *
You're not interested in text content consisting only of whitespace
=item *
You don't mind that when things get slurped into a hash the order is lost
=item *
You don't want fine-grained control of the formatting of generated XML
=item *
You would never use a hash key that was not a legal XML element name
=item *
You don't need help converting between different encodings
=back
In a serious XML project, you'll probably outgrow these assumptions fairly
quickly. This section of the document used to offer some advice on chosing a
more powerful option. That advice has now grown into the 'Perl-XML FAQ'
document which you can find at: L<http://perl-xml.sourceforge.net/faq/>
The advice in the FAQ boils down to a quick explanation of tree versus
event based parsers and then recommends:
For event based parsing, use SAX (do not set out to write any new code for
XML::Parser's handler API - it is obselete).
For tree-based parsing, you could choose between the 'Perlish' approach of
L<XML::Twig> and more standards based DOM implementations - preferably one with
XPath support.
=head1 SEE ALSO
B<XML::Simple> requires either L<XML::Parser> or L<XML::SAX>.
To generate documents with namespaces, L<XML::NamespaceSupport> is required.
The optional caching functions require L<Storable>.
Answers to Frequently Asked Questions about XML::Simple are bundled with this
distribution as: L<XML::Simple::FAQ>
=head1 COPYRIGHT
Copyright 1999-2004 Grant McLean E<lt>grantm@cpan.orgE<gt>
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
=cut

/MissionCockpit/tags/V0.2.5/perl/lib/threads.pm
0,0 → 1,1056
package threads;
use 5.008;
use strict;
use warnings;
our $VERSION = '1.71';
my $XS_VERSION = $VERSION;
$VERSION = eval $VERSION;
# Verify this Perl supports threads
require Config;
if (! $Config::Config{useithreads}) {
die("This Perl not built to support threads\n");
}
# Complain if 'threads' is loaded after 'threads::shared'
if ($threads::shared::threads_shared) {
warn <<'_MSG_';
Warning, threads::shared has already been loaded. To
enable shared variables, 'use threads' must be called
before threads::shared or any module that uses it.
_MSG_
}
# Declare that we have been loaded
$threads::threads = 1;
# Load the XS code
require XSLoader;
XSLoader::load('threads', $XS_VERSION);
### Export ###
sub import
{
my $class = shift; # Not used
# Exported subroutines
my @EXPORT = qw(async);
# Handle args
while (my $sym = shift) {
if ($sym =~ /^(?:stack|exit)/i) {
if (defined(my $arg = shift)) {
if ($sym =~ /^stack/i) {
threads->set_stack_size($arg);
} else {
$threads::thread_exit_only = $arg =~ /^thread/i;
}
} else {
require Carp;
Carp::croak("threads: Missing argument for option: $sym");
}
} elsif ($sym =~ /^str/i) {
import overload ('""' => \&tid);
} elsif ($sym =~ /^(?::all|yield)$/) {
push(@EXPORT, qw(yield));
} else {
require Carp;
Carp::croak("threads: Unknown import option: $sym");
}
}
# Export subroutine names
my $caller = caller();
foreach my $sym (@EXPORT) {
no strict 'refs';
*{$caller.'::'.$sym} = \&{$sym};
}
# Set stack size via environment variable
if (exists($ENV{'PERL5_ITHREADS_STACK_SIZE'})) {
threads->set_stack_size($ENV{'PERL5_ITHREADS_STACK_SIZE'});
}
}
### Methods, etc. ###
# Exit from a thread (only)
sub exit
{
my ($class, $status) = @_;
if (! defined($status)) {
$status = 0;
}
# Class method only
if (ref($class)) {
require Carp;
Carp::croak('Usage: threads->exit(status)');
}
$class->set_thread_exit_only(1);
CORE::exit($status);
}
# 'Constant' args for threads->list()
sub threads::all { }
sub threads::running { 1 }
sub threads::joinable { 0 }
# 'new' is an alias for 'create'
*new = \&create;
# 'async' is a function alias for the 'threads->create()' method
sub async (&;@)
{
unshift(@_, 'threads');
# Use "goto" trick to avoid pad problems from 5.8.1 (fixed in 5.8.2)
goto &create;
}
# Thread object equality checking
use overload (
'==' => \&equal,
'!=' => sub { ! equal(@_) },
'fallback' => 1
);
1;
__END__
=head1 NAME
threads - Perl interpreter-based threads
=head1 VERSION
This document describes threads version 1.71
=head1 SYNOPSIS
use threads ('yield',
'stack_size' => 64*4096,
'exit' => 'threads_only',
'stringify');
sub start_thread {
my @args = @_;
print('Thread started: ', join(' ', @args), "\n");
}
my $thr = threads->create('start_thread', 'argument');
$thr->join();
threads->create(sub { print("I am a thread\n"); })->join();
my $thr2 = async { foreach (@files) { ... } };
$thr2->join();
if (my $err = $thr2->error()) {
warn("Thread error: $err\n");
}
# Invoke thread in list context (implicit) so it can return a list
my ($thr) = threads->create(sub { return (qw/a b c/); });
# or specify list context explicitly
my $thr = threads->create({'context' => 'list'},
sub { return (qw/a b c/); });
my @results = $thr->join();
$thr->detach();
# Get a thread's object
$thr = threads->self();
$thr = threads->object($tid);
# Get a thread's ID
$tid = threads->tid();
$tid = $thr->tid();
$tid = "$thr";
# Give other threads a chance to run
threads->yield();
yield();
# Lists of non-detached threads
my @threads = threads->list();
my $thread_count = threads->list();
my @running = threads->list(threads::running);
my @joinable = threads->list(threads::joinable);
# Test thread objects
if ($thr1 == $thr2) {
...
}
# Manage thread stack size
$stack_size = threads->get_stack_size();
$old_size = threads->set_stack_size(32*4096);
# Create a thread with a specific context and stack size
my $thr = threads->create({ 'context' => 'list',
'stack_size' => 32*4096,
'exit' => 'thread_only' },
\&foo);
# Get thread's context
my $wantarray = $thr->wantarray();
# Check thread's state
if ($thr->is_running()) {
sleep(1);
}
if ($thr->is_joinable()) {
$thr->join();
}
# Send a signal to a thread
$thr->kill('SIGUSR1');
# Exit a thread
threads->exit();
=head1 DESCRIPTION
Perl 5.6 introduced something called interpreter threads. Interpreter threads
are different from I<5005threads> (the thread model of Perl 5.005) by creating
a new Perl interpreter per thread, and not sharing any data or state between
threads by default.
Prior to Perl 5.8, this has only been available to people embedding Perl, and
for emulating fork() on Windows.
The I<threads> API is loosely based on the old Thread.pm API. It is very
important to note that variables are not shared between threads, all variables
are by default thread local. To use shared variables one must also use
L<threads::shared>:
use threads;
use threads::shared;
It is also important to note that you must enable threads by doing C<use
threads> as early as possible in the script itself, and that it is not
possible to enable threading inside an C<eval "">, C<do>, C<require>, or
C<use>. In particular, if you are intending to share variables with
L<threads::shared>, you must C<use threads> before you C<use threads::shared>.
(C<threads> will emit a warning if you do it the other way around.)
=over
=item $thr = threads->create(FUNCTION, ARGS)
This will create a new thread that will begin execution with the specified
entry point function, and give it the I<ARGS> list as parameters. It will
return the corresponding threads object, or C<undef> if thread creation failed.
I<FUNCTION> may either be the name of a function, an anonymous subroutine, or
a code ref.
my $thr = threads->create('func_name', ...);
# or
my $thr = threads->create(sub { ... }, ...);
# or
my $thr = threads->create(\&func, ...);
The C<-E<gt>new()> method is an alias for C<-E<gt>create()>.
=item $thr->join()
This will wait for the corresponding thread to complete its execution. When
the thread finishes, C<-E<gt>join()> will return the return value(s) of the
entry point function.
The context (void, scalar or list) for the return value(s) for C<-E<gt>join()>
is determined at the time of thread creation.
# Create thread in list context (implicit)
my ($thr1) = threads->create(sub {
my @results = qw(a b c);
return (@results);
});
# or (explicit)
my $thr1 = threads->create({'context' => 'list'},
sub {
my @results = qw(a b c);
return (@results);
});
# Retrieve list results from thread
my @res1 = $thr1->join();
# Create thread in scalar context (implicit)
my $thr2 = threads->create(sub {
my $result = 42;
return ($result);
});
# Retrieve scalar result from thread
my $res2 = $thr2->join();
# Create a thread in void context (explicit)
my $thr3 = threads->create({'void' => 1},
sub { print("Hello, world\n"); });
# Join the thread in void context (i.e., no return value)
$thr3->join();
See L</"THREAD CONTEXT"> for more details.
If the program exits without all threads having either been joined or
detached, then a warning will be issued.
Calling C<-E<gt>join()> or C<-E<gt>detach()> on an already joined thread will
cause an error to be thrown.
=item $thr->detach()
Makes the thread unjoinable, and causes any eventual return value to be
discarded. When the program exits, any detached threads that are still
running are silently terminated.
If the program exits without all threads having either been joined or
detached, then a warning will be issued.
Calling C<-E<gt>join()> or C<-E<gt>detach()> on an already detached thread
will cause an error to be thrown.
=item threads->detach()
Class method that allows a thread to detach itself.
=item threads->self()
Class method that allows a thread to obtain its own I<threads> object.
=item $thr->tid()
Returns the ID of the thread. Thread IDs are unique integers with the main
thread in a program being 0, and incrementing by 1 for every thread created.
=item threads->tid()
Class method that allows a thread to obtain its own ID.
=item "$thr"
If you add the C<stringify> import option to your C<use threads> declaration,
then using a threads object in a string or a string context (e.g., as a hash
key) will cause its ID to be used as the value:
use threads qw(stringify);
my $thr = threads->create(...);
print("Thread $thr started...\n"); # Prints out: Thread 1 started...
=item threads->object($tid)
This will return the I<threads> object for the I<active> thread associated
with the specified thread ID. Returns C<undef> if there is no thread
associated with the TID, if the thread is joined or detached, if no TID is
specified or if the specified TID is undef.
=item threads->yield()
This is a suggestion to the OS to let this thread yield CPU time to other
threads. What actually happens is highly dependent upon the underlying
thread implementation.
You may do C<use threads qw(yield)>, and then just use C<yield()> in your
code.
=item threads->list()
=item threads->list(threads::all)
=item threads->list(threads::running)
=item threads->list(threads::joinable)
With no arguments (or using C<threads::all>) and in a list context, returns a
list of all non-joined, non-detached I<threads> objects. In a scalar context,
returns a count of the same.
With a I<true> argument (using C<threads::running>), returns a list of all
non-joined, non-detached I<threads> objects that are still running.
With a I<false> argument (using C<threads::joinable>), returns a list of all
non-joined, non-detached I<threads> objects that have finished running (i.e.,
for which C<-E<gt>join()> will not I<block>).
=item $thr1->equal($thr2)
Tests if two threads objects are the same thread or not. This is overloaded
to the more natural forms:
if ($thr1 == $thr2) {
print("Threads are the same\n");
}
# or
if ($thr1 != $thr2) {
print("Threads differ\n");
}
(Thread comparison is based on thread IDs.)
=item async BLOCK;
C<async> creates a thread to execute the block immediately following
it. This block is treated as an anonymous subroutine, and so must have a
semicolon after the closing brace. Like C<threads-E<gt>create()>, C<async>
returns a I<threads> object.
=item $thr->error()
Threads are executed in an C<eval> context. This method will return C<undef>
if the thread terminates I<normally>. Otherwise, it returns the value of
C<$@> associated with the thread's execution status in its C<eval> context.
=item $thr->_handle()
This I<private> method returns the memory location of the internal thread
structure associated with a threads object. For Win32, this is a pointer to
the C<HANDLE> value returned by C<CreateThread> (i.e., C<HANDLE *>); for other
platforms, it is a pointer to the C<pthread_t> structure used in the
C<pthread_create> call (i.e., C<pthread_t *>).
This method is of no use for general Perl threads programming. Its intent is
to provide other (XS-based) thread modules with the capability to access, and
possibly manipulate, the underlying thread structure associated with a Perl
thread.
=item threads->_handle()
Class method that allows a thread to obtain its own I<handle>.
=back
=head1 EXITING A THREAD
The usual method for terminating a thread is to
L<return()|perlfunc/"return EXPR"> from the entry point function with the
appropriate return value(s).
=over
=item threads->exit()
If needed, a thread can be exited at any time by calling
C<threads-E<gt>exit()>. This will cause the thread to return C<undef> in a
scalar context, or the empty list in a list context.
When called from the I<main> thread, this behaves the same as C<exit(0)>.
=item threads->exit(status)
When called from a thread, this behaves like C<threads-E<gt>exit()> (i.e., the
exit status code is ignored).
When called from the I<main> thread, this behaves the same as C<exit(status)>.
=item die()
Calling C<die()> in a thread indicates an abnormal exit for the thread. Any
C<$SIG{__DIE__}> handler in the thread will be called first, and then the
thread will exit with a warning message that will contain any arguments passed
in the C<die()> call.
=item exit(status)
Calling L<exit()|perlfunc/"exit EXPR"> inside a thread causes the whole
application to terminate. Because of this, the use of C<exit()> inside
threaded code, or in modules that might be used in threaded applications, is
strongly discouraged.
If C<exit()> really is needed, then consider using the following:
threads->exit() if threads->can('exit'); # Thread friendly
exit(status);
=item use threads 'exit' => 'threads_only'
This globally overrides the default behavior of calling C<exit()> inside a
thread, and effectively causes such calls to behave the same as
C<threads-E<gt>exit()>. In other words, with this setting, calling C<exit()>
causes only the thread to terminate.
Because of its global effect, this setting should not be used inside modules
or the like.
The I<main> thread is unaffected by this setting.
=item threads->create({'exit' => 'thread_only'}, ...)
This overrides the default behavior of C<exit()> inside the newly created
thread only.
=item $thr->set_thread_exit_only(boolean)
This can be used to change the I<exit thread only> behavior for a thread after
it has been created. With a I<true> argument, C<exit()> will cause only the
thread to exit. With a I<false> argument, C<exit()> will terminate the
application.
The I<main> thread is unaffected by this call.
=item threads->set_thread_exit_only(boolean)
Class method for use inside a thread to change its own behavior for C<exit()>.
The I<main> thread is unaffected by this call.
=back
=head1 THREAD STATE
The following boolean methods are useful in determining the I<state> of a
thread.
=over
=item $thr->is_running()
Returns true if a thread is still running (i.e., if its entry point function
has not yet finished or exited).
=item $thr->is_joinable()
Returns true if the thread has finished running, is not detached and has not
yet been joined. In other words, the thread is ready to be joined, and a call
to C<$thr-E<gt>join()> will not I<block>.
=item $thr->is_detached()
Returns true if the thread has been detached.
=item threads->is_detached()
Class method that allows a thread to determine whether or not it is detached.
=back
=head1 THREAD CONTEXT
As with subroutines, the type of value returned from a thread's entry point
function may be determined by the thread's I<context>: list, scalar or void.
The thread's context is determined at thread creation. This is necessary so
that the context is available to the entry point function via
L<wantarray()|perlfunc/"wantarray">. The thread may then specify a value of
the appropriate type to be returned from C<-E<gt>join()>.
=head2 Explicit context
Because thread creation and thread joining may occur in different contexts, it
may be desirable to state the context explicitly to the thread's entry point
function. This may be done by calling C<-E<gt>create()> with a hash reference
as the first argument:
my $thr = threads->create({'context' => 'list'}, \&foo);
...
my @results = $thr->join();
In the above, the threads object is returned to the parent thread in scalar
context, and the thread's entry point function C<foo> will be called in list
(array) context such that the parent thread can receive a list (array) from
the C<-E<gt>join()> call. (C<'array'> is synonymous with C<'list'>.)
Similarly, if you need the threads object, but your thread will not be
returning a value (i.e., I<void> context), you would do the following:
my $thr = threads->create({'context' => 'void'}, \&foo);
...
$thr->join();
The context type may also be used as the I<key> in the hash reference followed
by a I<true> value:
threads->create({'scalar' => 1}, \&foo);
...
my ($thr) = threads->list();
my $result = $thr->join();
=head2 Implicit context
If not explicitly stated, the thread's context is implied from the context
of the C<-E<gt>create()> call:
# Create thread in list context
my ($thr) = threads->create(...);
# Create thread in scalar context
my $thr = threads->create(...);
# Create thread in void context
threads->create(...);
=head2 $thr->wantarray()
This returns the thread's context in the same manner as
L<wantarray()|perlfunc/"wantarray">.
=head2 threads->wantarray()
Class method to return the current thread's context. This returns the same
value as running L<wantarray()|perlfunc/"wantarray"> inside the current
thread's entry point function.
=head1 THREAD STACK SIZE
The default per-thread stack size for different platforms varies
significantly, and is almost always far more than is needed for most
applications. On Win32, Perl's makefile explicitly sets the default stack to
16 MB; on most other platforms, the system default is used, which again may be
much larger than is needed.
By tuning the stack size to more accurately reflect your application's needs,
you may significantly reduce your application's memory usage, and increase the
number of simultaneously running threads.
Note that on Windows, address space allocation granularity is 64 KB,
therefore, setting the stack smaller than that on Win32 Perl will not save any
more memory.
=over
=item threads->get_stack_size();
Returns the current default per-thread stack size. The default is zero, which
means the system default stack size is currently in use.
=item $size = $thr->get_stack_size();
Returns the stack size for a particular thread. A return value of zero
indicates the system default stack size was used for the thread.
=item $old_size = threads->set_stack_size($new_size);
Sets a new default per-thread stack size, and returns the previous setting.
Some platforms have a minimum thread stack size. Trying to set the stack size
below this value will result in a warning, and the minimum stack size will be
used.
Some Linux platforms have a maximum stack size. Setting too large of a stack
size will cause thread creation to fail.
If needed, C<$new_size> will be rounded up to the next multiple of the memory
page size (usually 4096 or 8192).
Threads created after the stack size is set will then either call
C<pthread_attr_setstacksize()> I<(for pthreads platforms)>, or supply the
stack size to C<CreateThread()> I<(for Win32 Perl)>.
(Obviously, this call does not affect any currently extant threads.)
=item use threads ('stack_size' => VALUE);
This sets the default per-thread stack size at the start of the application.
=item $ENV{'PERL5_ITHREADS_STACK_SIZE'}
The default per-thread stack size may be set at the start of the application
through the use of the environment variable C<PERL5_ITHREADS_STACK_SIZE>:
PERL5_ITHREADS_STACK_SIZE=1048576
export PERL5_ITHREADS_STACK_SIZE
perl -e'use threads; print(threads->get_stack_size(), "\n")'
This value overrides any C<stack_size> parameter given to C<use threads>. Its
primary purpose is to permit setting the per-thread stack size for legacy
threaded applications.
=item threads->create({'stack_size' => VALUE}, FUNCTION, ARGS)
To specify a particular stack size for any individual thread, call
C<-E<gt>create()> with a hash reference as the first argument:
my $thr = threads->create({'stack_size' => 32*4096}, \&foo, @args);
=item $thr2 = $thr1->create(FUNCTION, ARGS)
This creates a new thread (C<$thr2>) that inherits the stack size from an
existing thread (C<$thr1>). This is shorthand for the following:
my $stack_size = $thr1->get_stack_size();
my $thr2 = threads->create({'stack_size' => $stack_size}, FUNCTION, ARGS);
=back
=head1 THREAD SIGNALLING
When safe signals is in effect (the default behavior - see L</"Unsafe signals">
for more details), then signals may be sent and acted upon by individual
threads.
=over 4
=item $thr->kill('SIG...');
Sends the specified signal to the thread. Signal names and (positive) signal
numbers are the same as those supported by
L<kill()|perlfunc/"kill SIGNAL, LIST">. For example, 'SIGTERM', 'TERM' and
(depending on the OS) 15 are all valid arguments to C<-E<gt>kill()>.
Returns the thread object to allow for method chaining:
$thr->kill('SIG...')->join();
=back
Signal handlers need to be set up in the threads for the signals they are
expected to act upon. Here's an example for I<cancelling> a thread:
use threads;
sub thr_func
{
# Thread 'cancellation' signal handler
$SIG{'KILL'} = sub { threads->exit(); };
...
}
# Create a thread
my $thr = threads->create('thr_func');
...
# Signal the thread to terminate, and then detach
# it so that it will get cleaned up automatically
$thr->kill('KILL')->detach();
Here's another simplistic example that illustrates the use of thread
signalling in conjunction with a semaphore to provide rudimentary I<suspend>
and I<resume> capabilities:
use threads;
use Thread::Semaphore;
sub thr_func
{
my $sema = shift;
# Thread 'suspend/resume' signal handler
$SIG{'STOP'} = sub {
$sema->down(); # Thread suspended
$sema->up(); # Thread resumes
};
...
}
# Create a semaphore and pass it to a thread
my $sema = Thread::Semaphore->new();
my $thr = threads->create('thr_func', $sema);
# Suspend the thread
$sema->down();
$thr->kill('STOP');
...
# Allow the thread to continue
$sema->up();
CAVEAT: The thread signalling capability provided by this module does not
actually send signals via the OS. It I<emulates> signals at the Perl-level
such that signal handlers are called in the appropriate thread. For example,
sending C<$thr-E<gt>kill('STOP')> does not actually suspend a thread (or the
whole process), but does cause a C<$SIG{'STOP'}> handler to be called in that
thread (as illustrated above).
As such, signals that would normally not be appropriate to use in the
C<kill()> command (e.g., C<kill('KILL', $$)>) are okay to use with the
C<-E<gt>kill()> method (again, as illustrated above).
Correspondingly, sending a signal to a thread does not disrupt the operation
the thread is currently working on: The signal will be acted upon after the
current operation has completed. For instance, if the thread is I<stuck> on
an I/O call, sending it a signal will not cause the I/O call to be interrupted
such that the signal is acted up immediately.
Sending a signal to a terminated thread is ignored.
=head1 WARNINGS
=over 4
=item Perl exited with active threads:
If the program exits without all threads having either been joined or
detached, then this warning will be issued.
NOTE: If the I<main> thread exits, then this warning cannot be suppressed
using C<no warnings 'threads';> as suggested below.
=item Thread creation failed: pthread_create returned #
See the appropriate I<man> page for C<pthread_create> to determine the actual
cause for the failure.
=item Thread # terminated abnormally: ...
A thread terminated in some manner other than just returning from its entry
point function, or by using C<threads-E<gt>exit()>. For example, the thread
may have terminated because of an error, or by using C<die>.
=item Using minimum thread stack size of #
Some platforms have a minimum thread stack size. Trying to set the stack size
below this value will result in the above warning, and the stack size will be
set to the minimum.
=item Thread creation failed: pthread_attr_setstacksize(I<SIZE>) returned 22
The specified I<SIZE> exceeds the system's maximum stack size. Use a smaller
value for the stack size.
=back
If needed, thread warnings can be suppressed by using:
no warnings 'threads';
in the appropriate scope.
=head1 ERRORS
=over 4
=item This Perl not built to support threads
The particular copy of Perl that you're trying to use was not built using the
C<useithreads> configuration option.
Having threads support requires all of Perl and all of the XS modules in the
Perl installation to be rebuilt; it is not just a question of adding the
L<threads> module (i.e., threaded and non-threaded Perls are binary
incompatible.)
=item Cannot change stack size of an existing thread
The stack size of currently extant threads cannot be changed, therefore, the
following results in the above error:
$thr->set_stack_size($size);
=item Cannot signal threads without safe signals
Safe signals must be in effect to use the C<-E<gt>kill()> signalling method.
See L</"Unsafe signals"> for more details.
=item Unrecognized signal name: ...
The particular copy of Perl that you're trying to use does not support the
specified signal being used in a C<-E<gt>kill()> call.
=back
=head1 BUGS AND LIMITATIONS
Before you consider posting a bug report, please consult, and possibly post a
message to the discussion forum to see if what you've encountered is a known
problem.
=over
=item Thread-safe modules
See L<perlmod/"Making your module threadsafe"> when creating modules that may
be used in threaded applications, especially if those modules use non-Perl
data, or XS code.
=item Using non-thread-safe modules
Unfortunately, you may encounter Perl modules that are not I<thread-safe>.
For example, they may crash the Perl interpreter during execution, or may dump
core on termination. Depending on the module and the requirements of your
application, it may be possible to work around such difficulties.
If the module will only be used inside a thread, you can try loading the
module from inside the thread entry point function using C<require> (and
C<import> if needed):
sub thr_func
{
require Unsafe::Module
# Unsafe::Module->import(...);
....
}
If the module is needed inside the I<main> thread, try modifying your
application so that the module is loaded (again using C<require> and
C<-E<gt>import()>) after any threads are started, and in such a way that no
other threads are started afterwards.
If the above does not work, or is not adequate for your application, then file
a bug report on L<http://rt.cpan.org/Public/> against the problematic module.
=item Current working directory
On all platforms except MSWin32, the setting for the current working directory
is shared among all threads such that changing it in one thread (e.g., using
C<chdir()>) will affect all the threads in the application.
On MSWin32, each thread maintains its own the current working directory
setting.
=item Environment variables
Currently, on all platforms except MSWin32, all I<system> calls (e.g., using
C<system()> or back-ticks) made from threads use the environment variable
settings from the I<main> thread. In other words, changes made to C<%ENV> in
a thread will not be visible in I<system> calls made by that thread.
To work around this, set environment variables as part of the I<system> call.
For example:
my $msg = 'hello';
system("FOO=$msg; echo \$FOO"); # Outputs 'hello' to STDOUT
On MSWin32, each thread maintains its own set of environment variables.
=item Parent-child threads
On some platforms, it might not be possible to destroy I<parent> threads while
there are still existing I<child> threads.
=item Creating threads inside special blocks
Creating threads inside C<BEGIN>, C<CHECK> or C<INIT> blocks should not be
relied upon. Depending on the Perl version and the application code, results
may range from success, to (apparently harmless) warnings of leaked scalar, or
all the way up to crashing of the Perl interpreter.
=item Unsafe signals
Since Perl 5.8.0, signals have been made safer in Perl by postponing their
handling until the interpreter is in a I<safe> state. See
L<perl58delta/"Safe Signals"> and L<perlipc/"Deferred Signals (Safe Signals)">
for more details.
Safe signals is the default behavior, and the old, immediate, unsafe
signalling behavior is only in effect in the following situations:
=over 4
=item * Perl has been built with C<PERL_OLD_SIGNALS> (see C<perl -V>).
=item * The environment variable C<PERL_SIGNALS> is set to C<unsafe> (see L<perlrun/"PERL_SIGNALS">).
=item * The module L<Perl::Unsafe::Signals> is used.
=back
If unsafe signals is in effect, then signal handling is not thread-safe, and
the C<-E<gt>kill()> signalling method cannot be used.
=item Returning closures from threads
Returning closures from threads should not be relied upon. Depending of the
Perl version and the application code, results may range from success, to
(apparently harmless) warnings of leaked scalar, or all the way up to crashing
of the Perl interpreter.
=item Returning objects from threads
Returning objects from threads does not work. Depending on the classes
involved, you may be able to work around this by returning a serialized
version of the object (e.g., using L<Data::Dumper> or L<Storable>), and then
reconstituting it in the joining thread. If you're using Perl 5.10.0 or
later, and if the class supports L<shared objects|threads::shared/"OBJECTS">,
you can pass them via L<shared queues| Thread::Queue>.
=item END blocks in threads
It is possible to add L<END blocks|perlmod/"BEGIN, UNITCHECK, CHECK, INIT and
END"> to threads by using L<require|perlfunc/"require VERSION"> or
L<eval|perlfunc/"eval EXPR"> with the appropriate code. These C<END> blocks
will then be executed when the thread's interpreter is destroyed (i.e., either
during a C<-E<gt>join()> call, or at program termination).
However, calling any L<threads> methods in such an C<END> block will most
likely I<fail> (e.g., the application may hang, or generate an error) due to
mutexes that are needed to control functionality within the L<threads> module.
For this reason, the use of C<END> blocks in threads is B<strongly>
discouraged.
=item Perl Bugs and the CPAN Version of L<threads>
Support for threads extends beyond the code in this module (i.e.,
F<threads.pm> and F<threads.xs>), and into the Perl interpreter itself. Older
versions of Perl contain bugs that may manifest themselves despite using the
latest version of L<threads> from CPAN. There is no workaround for this other
than upgrading to the latest version of Perl.
Even with the latest version of Perl, it is known that certain constructs
with threads may result in warning messages concerning leaked scalars or
unreferenced scalars. However, such warnings are harmless, and may safely be
ignored.
You can search for L<threads> related bug reports at
L<http://rt.cpan.org/Public/>. If needed submit any new bugs, problems,
patches, etc. to: L<http://rt.cpan.org/Public/Dist/Display.html?Name=threads>
=back
=head1 REQUIREMENTS
Perl 5.8.0 or later
=head1 SEE ALSO
L<threads> Discussion Forum on CPAN:
L<http://www.cpanforum.com/dist/threads>
Annotated POD for L<threads>:
L<http://annocpan.org/~JDHEDDEN/threads-1.71/threads.pm>
Source repository:
L<http://code.google.com/p/threads-shared/>
L<threads::shared>, L<perlthrtut>
L<http://www.perl.com/pub/a/2002/06/11/threads.html> and
L<http://www.perl.com/pub/a/2002/09/04/threads.html>
Perl threads mailing list:
L<http://lists.cpan.org/showlist.cgi?name=iThreads>
Stack size discussion:
L<http://www.perlmonks.org/?node_id=532956>
=head1 AUTHOR
Artur Bergman E<lt>sky AT crucially DOT netE<gt>
CPAN version produced by Jerry D. Hedden <jdhedden AT cpan DOT org>
=head1 LICENSE
threads is released under the same license as Perl.
=head1 ACKNOWLEDGEMENTS
Richard Soderberg E<lt>perl AT crystalflame DOT netE<gt> -
Helping me out tons, trying to find reasons for races and other weird bugs!
Simon Cozens E<lt>simon AT brecon DOT co DOT ukE<gt> -
Being there to answer zillions of annoying questions
Rocco Caputo E<lt>troc AT netrus DOT netE<gt>
Vipul Ved Prakash E<lt>mail AT vipul DOT netE<gt> -
Helping with debugging
Dean Arnold E<lt>darnold AT presicient DOT comE<gt> -
Stack size API
=cut