libglib-perl 3:1.260-1 / usr / lib / perl5 / Glib.pm

# Copyright (C) 2003-2012 by the gtk2-perl team (see the file AUTHORS for
# the full list)
#
# This library is free software; you can redistribute it and/or modify it under
# the terms of the GNU Library General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# This library is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU Library General Public License for
# more details.
#
# You should have received a copy of the GNU Library General Public License
# along with this library; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# $Id$
#

package Glib;

use 5.008;
use strict;
use warnings;
use Exporter;
require DynaLoader;
our @ISA = qw(DynaLoader Exporter);

use constant {
	TRUE  => 1,
	FALSE => !1, # can't use !TRUE at this point
	SOURCE_CONTINUE => 1,
	SOURCE_REMOVE   => !1,
	G_PRIORITY_HIGH         => -100,
	G_PRIORITY_DEFAULT      =>  0,
	G_PRIORITY_HIGH_IDLE    =>  100,
	G_PRIORITY_DEFAULT_IDLE =>  200,
	G_PRIORITY_LOW	        =>  300,
	G_PARAM_READWRITE       => [qw/readable writable/],
};

# export nothing by default.
# export functions and constants by request.
our %EXPORT_TAGS = (
	constants => [qw/
			TRUE
			FALSE
			SOURCE_CONTINUE
			SOURCE_REMOVE
			G_PRIORITY_HIGH
			G_PRIORITY_DEFAULT
			G_PRIORITY_HIGH_IDLE
			G_PRIORITY_DEFAULT_IDLE
			G_PRIORITY_LOW
			G_PARAM_READWRITE
			/],
	functions => [qw/
			filename_to_unicode
			filename_from_unicode
			filename_to_uri
			filename_from_uri
			filename_display_name
			filename_display_basename
			/],
);
our @EXPORT_OK = map { @$_ } values %EXPORT_TAGS;
$EXPORT_TAGS{all} = \@EXPORT_OK;

our $VERSION = '1.260';

sub dl_load_flags { $^O eq 'darwin' ? 0x00 : 0x01 }

Glib->bootstrap ($VERSION);

package Glib::Flags;

use overload
   'bool' => \&bool,
   '+'    => \&union,     '|'    => \&union,
   '-'    => \&sub,
   '>='   => \&ge,
   '=='   => \&eq,        'eq'   => \&eq,
   '!='   => \&ne,        'ne'   => \&ne,
   '*'    => \&intersect, '&'    => \&intersect,
   '/'    => \&xor,       '^'    => \&xor,
   '@{}'  => \&as_arrayref,
   '""'   => sub { "[ @{$_[0]} ]" },
   fallback => 1;

package Glib::Error;

use overload
   '""' => sub { $_[0]->message.$_[0]->location },
   fallback => 1;

sub location { $_[0]->{location} }
sub message { $_[0]->{message} }
sub domain { $_[0]->{domain} }
sub value { $_[0]->{value} }
sub code { $_[0]->{code} }

package Glib::Object::Property;

use Carp;

sub TIESCALAR
{
# in the array reference the elements are:
#	[0] Glib::Object
#	[1] property name

	bless [ $_[1], $_[2] ], $_[0];
}

sub STORE { croak 'property '.$_[0][1].' is read-only'; }

sub FETCH { '[write-only]'; }

package Glib::Object::Property::Readable;

our @ISA = qw/Glib::Object::Property/;

sub FETCH { $_[0][0]->get_property ($_[0][1]); }

package Glib::Object::Property::Writable;

our @ISA = qw/Glib::Object::Property/;

sub STORE { $_[0][0]->set_property ($_[0][1], $_[1]); }

package Glib::Object::Property::ReadWrite;

our @ISA = qw/Glib::Object::Property/;

*FETCH = \&Glib::Object::Property::Readable::FETCH;
*STORE = \&Glib::Object::Property::Writable::STORE;

package Glib::Object;

use Carp;

sub tie_properties
{
	my $self = shift;	# the object
	my $all = shift;	# add all properties, up heirarchy

	my @props = $self->list_properties;
	my $package = ref $self;
	my $name;
	foreach my $prop (@props)
	{
		# skip to next if it doesn't belong to this package and
		# they don't want everything tied
		next if ($prop->{owner_type} ne $package and not $all);

		$name = $prop->{name};
		$name =~ s/-/_/g;

		carp "overwriting existing non-tied hash key $name"
			if (exists ($self->{$name})
				and not tied $self->{$name});

		if ($prop->{flags} >= ["readable", "writable"]) {
                        tie $self->{$name},
                                'Glib::Object::Property::ReadWrite',
                                $self, $name;
                } elsif ($prop->{flags} >= "readable") {
                        tie $self->{$name},
                                'Glib::Object::Property::Readable',
                                $self, $name;
                } elsif ($prop->{flags} >= "writable") {
			tie $self->{$name},
				'Glib::Object::Property::Writable',
				$self, $name;
                } else {
                        # if it's not readable and not writable what is it?
		}
	}
}

package Glib::Object::_LazyLoader;

use strict;
no strict qw(refs);
use vars qw($AUTOLOAD);
push @Carp::CARP_NOT, __PACKAGE__;

# These two overrides won't keep explicit calls to UNIVERSAL::(isa|can)
# from breaking if called before anything is loaded, but those should
# be quite rare.

sub isa {
	# we really shouldn't get in here at all if $_[0] is undefined.
	_load (ref($_[0]) || $_[0]);
	$_[0]->SUPER::isa ($_[1]);
}

sub can {
	# we really shouldn't get in here at all if $_[0] is undefined.
	_load (ref($_[0]) || $_[0]);
	$_[0]->SUPER::can ($_[1]);
}

sub AUTOLOAD {
	(my $method = $AUTOLOAD) =~ s/^.*:://;
	(my $lazy_class = $AUTOLOAD) =~ s/::[^:]*$//;
	my $object_or_type = shift;

	_load ($lazy_class);

	die "Something is very broken, couldn't lazy load $lazy_class"
		if $object_or_type->isa (__PACKAGE__);

	# try again
	return $object_or_type->$method (@_);
}

package Glib;

1;
__END__

=head1 NAME

Glib - Perl wrappers for the GLib utility and Object libraries

=head1 SYNOPSIS

  use Glib;

=head1 ABSTRACT

This module provides perl access to GLib and GLib's GObject libraries.
GLib is a portability and utility library; GObject provides a generic
type system with inheritance and a powerful signal system.  Together
these libraries are used as the foundation for many of the libraries
that make up the Gnome environment, and are used in many unrelated
projects.

=head1 DESCRIPTION

This wrapper attempts to provide a perlish interface while remaining
as true as possible to the underlying C API, so that any reference
materials you can find on using GLib may still apply to using the
libraries from perl.  This module also provides facilities for creating
wrappers for other GObject-based libraries.  The L<SEE ALSO> section
contains pointers to all sorts of good information.

=head1 PERL VERSUS C

GLib provides to C programs many of the same facilities Perl offers
natively.  Where GLib's functionality overlaps Perl's, Perl's is favored.
Some concepts have been eliminated entirely, as Perl is a higher-level
language than C.  In other instances we've had to add or change APIs to
make sense in Perl.  Here's a quick run-down:

=head2 Perl Already Does That

The GLib types GList (a doubly-linked list), GSList (singly-linked list),
GHashTable, GArray, etc have all been replaced by native Perl datatypes.  In
fact, many functions which take GLists or arrays simply accept lists on the
Perl stack.  For the most part, GIOChannels are no more functional than Perl
file handles, so you won't see any GIOChannels.  GClosures are not visible at
the Perl level, because Perl code references do the same thing.  Just about any
function taking either a C function pointer or a GClosure will accept a code
reference in Perl.  (In fact, you can probably get away with just a subroutine
name in many spots, provided you aren't using strict subs.)

=head2 Don't Worry About That

Some concepts have been eliminated; you need never worry about
reference-counting on GObjects or having to free GBoxed structures.  Perl is a
garbage-collected language, and we've put a lot of work into making the
bindings take care of memory for you in a way that feels natural to a Perl
developer.  You won't see GValues in Perl (that's just a C structure with Perl
scalar envy, anyway).

=head2 This Is Now That

Other GLib concepts have been converted to an analogous Perl concept.

The GType id will never be seen in Perl, as the package name serves that
purpose.  Several packages corresponding to the GTypes of the fundamental types
have been registered for you:

 G_TYPE_STRING     Glib::String
 G_TYPE_INT        Glib::Int
 G_TYPE_UINT       Glib::UInt
 G_TYPE_DOUBLE     Glib::Double
 G_TYPE_BOOLEAN    Glib::Boolean

The remaining fundamentals (char/uchar, short, float, etc) are also registered
so that we can properly interact with properties of C objects, but perl really
only uses ints, uints, and doubles.  Oh, and we created a GBoxed type for Perl
scalars so you can use scalars where any boxed type would be allowed (e.g.
GtkTreeModel columns):

 Glib::Scalar

Functions that can return false and set a GError in C raise an exception in
Perl, using an exception object based on the GError for $@; see L<Glib::Error>.
Trapping exceptions in signals is a sticky issue, so they get their own
section; see L<EXCEPTIONS>.

Enumerations and flags are treated as strings and arrays of strings,
respectively.  GLib provides a way to register nicknames for enumeration
values, and the Perl bindings use these nicknames for the real values, so that
we never have to deal with numbers in Perl. This can get a little cumbersome
for bitfields, but it's very nice when you forget a flag value, as the bindings
will tell you what values are accepted when you pass something invalid. Also,
the bindings consider the - and _ characters to be equivalent, so that signal
and property names can be properly stringified by the => operator.  For
example, the following are equivalent:

  # property foo-matic of type FooType, using the
  # value FOO_SOMETHING_COOL.  its nickname would be
  # 'something-cool'.  you may use either the full
  # name or the nickname when supplying values to perl.
  $object->set ('foo-matic', 'FOO_SOMETHING_COOL');
  $object->set ('foo_matic', 'something_cool');
  $object->set (foo_matic => 'something-cool');

Beware that Perl will always return to you the nickname form, with the dash.

Flags have some additional magic abilities in the form of overloaded
operators:

  + or |   union of two flagsets ("add")
  -        difference of two flagsets ("sub", "remove")
  * or &   intersection of two bitsets ("and")
  / or ^   symmetric difference ("xor", you will rarely need this)
  >=       contains-operator ("is the left set a superset of the right set?")
  ==       equality

In addition, flags in boolean context indicate whether they are empty or
not, which allows you to write common operations naturally:

  $widget->set_events ($widget->get_events - "motion_notify_mask");
  $widget->set_events ($widget->get_events - ["motion_notify_mask",
                                              "button_press_mask"]);

  # shift pressed (both work, it's a matter of taste)
  if ($event->state >= "shift-mask") { ...
  if ($event->state * "shift-mask") { ...

  # either shift OR control pressed?
  if ($event->state * ["shift-mask", "control-mask"]) { ...

  # both shift AND control pressed?
  if ($event->state >= ["shift-mask", "control-mask"]) { ...

In general, C<+> and C<-> work as expected to add or remove flags. To test
whether I<any> bits are set in a mask, you use C<$mask * ...>, and to test
whether I<all> bits are set in a mask, you use C<< $mask >= ... >>.

When dereferenced as an array C<@$flags> or C<< $flags->[...] >>, you can
access the flag values directly as strings (but you are not allowed to
modify the array), and when stringified C<"$flags"> a flags value will
output a human-readable version of its contents.

=head2 It's All the Same

For the most part, the remaining bits of GLib are unchanged.  GMainLoop is now
Glib::MainLoop, GObject is now Glib::Object, GBoxed is now Glib::Boxed, etc.

=head1 FILENAMES, URIS AND ENCODINGS

Perl knows two datatypes, unicode text and binary bytes. Filenames on
a system that doesn't use a utf-8 locale are often stored in a local
encoding ("binary bytes"). Gtk+ and descendants, however, internally
work in unicode most of the time, so when feeding a filename into a
GLib/Gtk+ function that expects a filename, you first need to convert it
from the local encoding to unicode.

This involves some elaborate guessing, which perl currently avoids, but
GLib and Gtk+ do. As an exception, some Gtk+ functions want a filename
in local encoding, but the perl interface usually works around this by
automatically converting it for you.

In short: Everything should be in unicode on the perl level.

The following functions expose the conversion algorithm that GLib uses.

These functions are only necessary when you want to use perl functions
to manage filenames returned by a GLib/Gtk+ function, or when you feed
filenames into GLib/Gtk+ functions that have their source outside your
program (e.g. commandline arguments, readdir results etc.).

These functions are available as exports by request (see L</Exports>),
and also support method invocation syntax for pathological consistency
with the OO syntax of the rest of the bindings.

=over 4

=item $filename = filename_to_unicode $filename_in_local_encoding

=item $filename = Glib->filename_to_unicode ($filename_in_local_encoding)

Convert a perl string that supposedly contains a filename in local
encoding into a filename represented as unicode, the same way that GLib
does it internally.

Example:

   $gtkfilesel->set_filename (filename_to_unicode $ARGV[1]);

This function will croak() if the conversion cannot be made, e.g., because the
utf-8 is invalid.

=item $filename_in_local_encoding = filename_from_unicode $filename

=item $filename_in_local_encoding = Glib->filename_from_unicode ($filename)

Converts a perl string containing a filename into a filename in the local
encoding in the same way GLib does it.

Example:

   open MY, "<", filename_from_unicode $gtkfilesel->get_filename;

=back

It might
be useful to know that perl currently has no policy at all regarding
filename issues, if your scalar happens to be in utf-8 internally it will
use utf-8, if it happens to be stored as bytes, it will use it as-is.

When dealing with filenames that you need to display, there is a much easier
way, as of Glib 1.120 and glib 2.6.0:

=over 4

=item $uft8_string = filename_display_name ($filename)

=item $uft8_string = filename_display_basename ($filename)

Given a I<$filename> in filename encoding, return the filename, or just
the file's basename, in utf-8.  Unlike the other functions described above,
this one is guaranteed to return valid utf-8, but the conversion is not
necessarily reversible.  These functions are intended to be used for failsafe
display of filenames, for example in gtk+ labels.

Since glib 2.6, Glib 1.12

=back

The following convert filenames to and from URI encoding.  (See also
L<URI::file>.)

=over 4

=item $string = filename_to_uri ($filename, $hostname)

=item $string = Glib->filename_to_uri ($filename, $hostname)

Return a "file://" schema URI for a filename.  Unsafe and non-ascii chars in
C<$filename> are escaped with URI "%" forms.

C<$filename> must be an absolute path as a byte string in local filesystem
encoding.  C<$hostname> is a utf-8 string, or empty or C<undef> for no host
specified.  For example,

    filename_to_uri ('/my/x%y/<dir>/foo.html', undef);
    # returns 'file:///my/x%25y/%3Cdir%3E/foo.html'

If C<$filename> is a relative path or C<$hostname> doesn't look like a
hostname then C<filename_to_uri> croaks with a C<Glib::Error>.

When using the class style C<< Glib->filename_to_uri >> remember that the
C<$hostname> argument is mandatory.  If you forget then it looks like a
2-argument call with filename of "Glib" and hostname of what you meant to be
the filename.

=item $filename = filename_from_uri ($uri)

=item ($filename, $hostname) = filename_from_uri ($uri)

Extract the filename and hostname from a "file://" schema URI.  In scalar
context just the filename is returned, in array context both filename and
hostname are returned.

The filename returned is bytes in the local filesystem encoding and with the
OS path separator character.  The hostname returned is utf-8.  For example,

    ($f,$h) = filename_from_uri ('file://foo.com/r%26b/bar.html');
    # returns '/r&b/bar.html' and 'foo.com' on Unix

If C<$uri> is not a "file:", or is mal-formed, or the hostname part doesn't
look like a host name then C<filename_from_uri> croaks with a
C<Glib::Error>.

=back


=head1 EXCEPTIONS

The C language doesn't support exceptions; GLib is a C library, and of course
doesn't support exceptions either.  In Perl, we use die and eval to raise
and trap exceptions as a rather common practice.  So, the bindings have to
work a little black magic behind the scenes to keep GLib from exploding when
the Perl program uses exceptions.  Unfortunately, a little of this magic
has to leak out to where you can see it at the Perl level.

Signal and event handlers are run in an eval context; if an exception occurs
in such a handler and you don't catch it, Perl will report that an error
occurred, and then go on about its business like nothing happened.

You may register subroutines as exception handlers, to be called when such
an exception is trapped.  Another function removes them for you.

  $tag = Glib->install_exception_handler (\&my_handler);
  Glib->remove_exception_handler ($tag);

The exception handler will get a fresh copy of the $@ of the offending
exception on the argument stack, and is expected to return non-zero if the
handler is to remain installed.  If it returns false, the handler will be
removed.

  sub my_handler {
      if ($_[0] =~ m/ftang quisinart/) {
           clean_up_after_ftang ();
      }
      1; # live to fight another day
  }

You can register as many handlers as you like; they will all run
independently.

An important thing to remember is that exceptions do not cross main loops.
In fact, exceptions are completely distinct from main loops.  If you need
to quit a main loop when an exception occurs, install a handler that quits
the main loop, but also ask yourself if you are using exceptions for flow
control or exception handling.

=head1 LOG MESSAGES

GLib's g_log function provides a flexible mechanism for reporting messages,
and most GLib-based C libraries use this mechanism for warnings, assertions,
critical messages, etc.  The Perl bindings offer a mechanism for routing
these messages through Perl's native system, warn() and die().  Extensions
should register the log domains they wrap for this to happen fluidly.
[FIXME say more here]

=head1 64 BIT INTEGERS

Since perl's integer data type can only hold 32 bit values on all 32 bit
machines and even on some 64 bit machines, Glib converts 64 bit integers to and
from strings if necessary.  These strings can then be used to feed one of the
various big integer modules.  Make sure you don't let your strings get into
numerical context before passing them into a Glib function because in this
case, perl will convert the number to scientific notation which at this point
is not understood by Glib's converters.

Here is an overview of what big integer modules are available.  First of all,
there's Math::BigInt.  It has everything you will ever need, but its pure-Perl
implementation is also rather slow.  There are multiple ways around this,
though.

=over

=item L<Math::BigInt::FastCalc>

L<Math::BigInt::FastCalc> can help avoid the glacial speed of vanilla
L<Math::BigInt::Calc>.  Recent versions of L<Math::BigInt> will automatically
use L<Math::BigInt::FastCalc> in place of L<Math::BigInt::Calc> when available.
Other options include L<Math::BigInt::GMP> or L<Math::BigInt::Pari>, which
however have much larger dependencies.

=item L<Math::BigInt::Lite>

Then there's L<Math::BigInt::Lite>, which uses native Perl integer operations
as long as Perl integers have sufficient range, and upgrades itself to
L<Math::BigInt> when Perl integers would overflow. This must be used in place
of L<Math::BigInt>.

=item L<bigint> / L<bignum> / L<bigfloat>

Finally, there's the bigint/bignum/bigfloat pragmata, which automatically load
the corresponding Math:: modules and which will autobox constants.
bignum/bigint will automatically use L<Math::BigInt::Lite> if it's available.

=back

=head1 EXPORTS

For the most part, gtk2-perl avoids exporting things.  Nothing is exported by
default, but some functions and constants in Glib are available by request;
you can also get all of them with the export tag "all".

=over

=item Tag: constants

  TRUE
  FALSE
  SOURCE_CONTINUE
  SOURCE_REMOVE
  G_PRIORITY_HIGH
  G_PRIORITY_DEFAULT
  G_PRIORITY_HIGH_IDLE
  G_PRIORITY_DEFAULT_IDLE
  G_PRIORITY_LOW
  G_PARAM_READWRITE

=item Tag: functions

  filename_from_unicode
  filename_to_unicode
  filename_from_uri
  filename_to_uri
  filename_display_basename
  filename_display_name

=back

=head1 SEE ALSO

L<Glib::Object::Subclass> explains how to create your own gobject subclasses
in Perl.

L<Glib::index> lists the automatically-generated API reference for the
various packages in Glib.

This module is the basis for the Gtk2 module, so most of the references
you'll be able to find about this one are tied to that one.  The perl
interface aims to be very simply related to the C API, so see the C API
reference documentation:

  GLib - http://developer.gnome.org/doc/API/2.0/glib/
  GObject - http://developer.gnome.org/doc/API/2.0/gobject/

This module serves as the foundation for any module which needs to bind
GLib-based C libraries to perl.

  Glib::devel - Binding developer's overview of Glib's internals
  Glib::xsapi - internal API reference for GPerl
  Glib::ParseXSDoc - extract API docs from xs sources.
  Glib::GenPod - turn the output of Glib::ParseXSDoc into POD
  Glib::MakeHelper - Makefile.PL utilities for Glib-based extensions

  Yet another document, available separately, ties it all together:
    http://gtk2-perl.sourceforge.net/doc/binding_howto.pod.html

For gtk2-perl itself, see its website at

  gtk2-perl - http://gtk2-perl.sourceforge.net/

A mailing list exists for discussion of using gtk2-perl and related
modules.  Archives and subscription information are available at
http://lists.gnome.org/.


=head1 AUTHORS

=encoding utf8

muppet, E<lt>scott at asofyet dot orgE<gt>, who borrowed heavily from the work
of Göran Thyni, E<lt>gthyni at kirra dot netE<gt> and Guillaume Cottenceau
E<lt>gc at mandrakesoft dot comE<gt> on the first gtk2-perl module, and from
the sourcecode of the original gtk-perl and pygtk projects.  Marc Lehmann
E<lt>pcg at goof dot comE<gt> did lots of great work on the magic of making
Glib::Object wrapper and subclassing work like they should.  Ross McFarland
<rwmcfa1 at neces dot com> wrote quite a bit of the documentation generation
tools.  Torsten Schoenfeld <kaffeetisch at web dot de> contributed little
patches and tests here and there.

=head1 COPYRIGHT AND LICENSE

Copyright 2003-2011 by muppet and the gtk2-perl team

This library is free software; you can redistribute it and/or modify
it under the terms of the Lesser General Public License (LGPL).  For
more information, see http://www.fsf.org/licenses/lgpl.txt

=cut