package XML::SAX::Exception;

use strict;

use overload '""' => "stringify",
    'fallback' => 1;

use vars qw/$StackTrace $VERSION/;
$VERSION = '1.01';
use Carp;

$StackTrace = $ENV{XML_DEBUG} || 0;

# Other exception classes:

@XML::SAX::Exception::NotRecognized::ISA = ('XML::SAX::Exception');
@XML::SAX::Exception::NotSupported::ISA = ('XML::SAX::Exception');
@XML::SAX::Exception::Parse::ISA = ('XML::SAX::Exception');


sub throw {
    my $class = shift;
    if (ref($class)) {
        die $class;
    }
    die $class->new(@_);
}

sub new {
    my $class = shift;
    my %opts = @_;
    confess "Invalid options: " . join(', ', keys %opts) unless exists $opts{Message};
    
    bless { ($StackTrace ? (StackTrace => stacktrace()) : ()), %opts },
        $class;
}

sub stringify {
    my $self = shift;
    local $^W;
    my $error;
    if (exists $self->{LineNumber}) {
        $error = $self->{Message} . " [Ln: " . $self->{LineNumber} . 
                ", Col: " . $self->{ColumnNumber} . "]";
    }
    else {
        $error = $self->{Message};
    }
    if ($StackTrace) {
        $error .= stackstring($self->{StackTrace});
    }
    $error .= "\n";
    return $error;
}

sub stacktrace {
    my $i = 2;
    my @fulltrace;
    while (my @trace = caller($i++)) {
        my %hash;
        @hash{qw(Package Filename Line)} = @trace[0..2];
        push @fulltrace, \%hash;
    }
    return \@fulltrace;
}

sub stackstring {
    my $stacktrace = shift;
    my $string = "\nFrom:\n";
    foreach my $current (@$stacktrace) {
        $string .= $current->{Filename} . " Line: " . $current->{Line} . "\n";
    }
    return $string;
}

1;

__END__

=head1 NAME

XML::SAX::Exception - Exception classes for XML::SAX

=head1 SYNOPSIS

  throw XML::SAX::Exception::NotSupported(
          Message => "The foo feature is not supported",
          );

=head1 DESCRIPTION

This module is the base class for all SAX Exceptions, those defined in
the spec as well as those that one may create for one's own SAX errors.

There are three subclasses included, corresponding to those of the SAX
spec:

  XML::SAX::Exception::NotSupported
  XML::SAX::Exception::NotRecognized
  XML::SAX::Exception::Parse

Use them wherever you want, and as much as possible when you encounter
such errors. SAX is meant to use exceptions as much as possible to 
flag problems.

=head1 CREATING NEW EXCEPTION CLASSES

All you need to do to create a new exception class is:

  @XML::SAX::Exception::MyException::ISA = ('XML::SAX::Exception')

The given package doesn't need to exist, it'll behave correctly this 
way. If your exception refines an existing exception class, then you
may also inherit from that instead of from the base class.

=head1 THROWING EXCEPTIONS

This is as simple as exemplified in the SYNOPSIS. In fact, there's 
nothing more to know. All you have to do is:

  throw XML::SAX::Exception::MyException( Message => 'Something went wrong' );

and voila, you've thrown an exception which can be caught in an eval block.

=cut


=head1 COPYRIGHT

=for COPYRIGHT BEGIN

Copyright 2022 University of Southampton.
EPrints 3.4 is supplied by EPrints Services.

http://www.eprints.org/eprints-3.4/

=for COPYRIGHT END

=for LICENSE BEGIN

This file is part of EPrints 3.4 L<http://www.eprints.org/>.

EPrints 3.4 and this file are released under the terms of the
GNU Lesser General Public License version 3 as published by
the Free Software Foundation unless otherwise stated.

EPrints 3.4 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with EPrints 3.4.
If not, see L<http://www.gnu.org/licenses/>.

=for LICENSE END