File Coverage

lib/Template/Iterator.pm

Criterion	Covered	Total	%
statement	79	84	94.0
branch	32	34	94.1
condition	7	10	70.0
subroutine	16	17	94.1
pod	7	7	100.0
total	141	152	92.7

#============================================================= -*-Perl-*-
#
# Template::Iterator
#
# DESCRIPTION
#
#   Module defining an iterator class which is used by the FOREACH
#   directive for iterating through data sets.  This may be
#   sub-classed to define more specific iterator types.
#
# AUTHOR
#   Andy Wardley
#
# COPYRIGHT
#   Copyright (C) 1996-2007 Andy Wardley.  All Rights Reserved.
#
#   This module is free software; you can redistribute it and/or
#   modify it under the same terms as Perl itself.
#
#============================================================================

package Template::Iterator;

use strict;
use warnings;
use base 'Template::Base';
use Template::Constants;
use Template::Exception;
use Scalar::Util qw(blessed);

use constant ODD  => 'odd';
use constant EVEN => 'even';

our $VERSION = 2.68;
our $DEBUG   = 0 unless defined $DEBUG;
our $AUTOLOAD;

#========================================================================
#                      -----  CLASS METHODS -----
#========================================================================

#------------------------------------------------------------------------
# new(\@target, \%options)
#
# Constructor method which creates and returns a reference to a new
# Template::Iterator object.  A reference to the target data (array
# or hash) may be passed for the object to iterate through.
#------------------------------------------------------------------------

sub new {
    my $class  = shift;
    my $data   = shift || [ ];
    my $params = shift || { };

    if (ref $data eq 'HASH') {
        # map a hash into a list of { key => ???, value => ??? } hashes,
        # one for each key, sorted by keys
        $data = [ map { { key => $_, value => $data->{ $_ } } }
                  sort keys %$data ];
    }
    elsif (blessed($data) && $data->can('as_list')) {
        $data = $data->as_list();
    }
    elsif (ref $data ne 'ARRAY') {
        # coerce any non-list data into an array reference
        $data  = [ $data ] ;
    }

    bless {
        _DATA  => $data,
        _ERROR => '',
    }, $class;
}


#========================================================================
#                   -----  PUBLIC OBJECT METHODS -----
#========================================================================

#------------------------------------------------------------------------
# get_first()
#
# Initialises the object for iterating through the target data set.  The
# first record is returned, if defined, along with the STATUS_OK value.
# If there is no target data, or the data is an empty set, then undef
# is returned with the STATUS_DONE value.
#------------------------------------------------------------------------

sub get_first {
    my $self  = shift;
    my $data  = $self->{ _DATA };

    $self->{ _DATASET } = $self->{ _DATA };
    my $size = scalar @$data;
    my $index = 0;

    return (undef, Template::Constants::STATUS_DONE) unless $size;

    # initialise various counters, flags, etc.
    @$self{ qw( SIZE MAX INDEX COUNT FIRST LAST ) }
            = ( $size, $size - 1, $index, 1, 1, $size > 1 ? 0 : 1, undef );
    @$self{ qw( PREV NEXT ) } = ( undef, $self->{ _DATASET }->[ $index + 1 ]);

    return $self->{ _DATASET }->[ $index ];
}



#------------------------------------------------------------------------
# get_next()
#
# Called repeatedly to access successive elements in the data set.
# Should only be called after calling get_first() or a warning will
# be raised and (undef, STATUS_DONE) returned.
#------------------------------------------------------------------------

sub get_next {
    my $self = shift;
    my ($max, $index) = @$self{ qw( MAX INDEX ) };
    my $data = $self->{ _DATASET };

    # warn about incorrect usage
    unless (defined $index) {
        my ($pack, $file, $line) = caller();
        warn("iterator get_next() called before get_first() at $file line $line\n");
        return (undef, Template::Constants::STATUS_DONE);   ## RETURN ##
    }

    # if there's still some data to go...
    if ($index < $max) {
        # update counters and flags
        $index++;
        @$self{ qw( INDEX COUNT FIRST LAST ) }
        = ( $index, $index + 1, 0, $index == $max ? 1 : 0 );
        @$self{ qw( PREV NEXT ) } = @$data[ $index - 1, $index + 1 ];
        return $data->[ $index ];                           ## RETURN ##
    }
    else {
        return (undef, Template::Constants::STATUS_DONE);   ## RETURN ##
    }
}


#------------------------------------------------------------------------
# get_all()
#
# Method which returns all remaining items in the iterator as a Perl list
# reference.  May be called at any time in the life-cycle of the iterator.
# The get_first() method will be called automatically if necessary, and
# then subsequent get_next() calls are made, storing each returned
# result until the list is exhausted.
#------------------------------------------------------------------------

sub get_all {
    my $self = shift;
    my ($max, $index) = @$self{ qw( MAX INDEX ) };
    my @data;

    # handle cases where get_first() has yet to be called.
    unless (defined $index) {
        my ($first, $status) = $self->get_first;

        # refresh $max and $index, after get_first updates MAX and INDEX
        ($max, $index) = @$self{ qw( MAX INDEX ) };

        # empty lists are handled here.
        if ($status && $status == Template::Constants::STATUS_DONE) {
            return (undef, Template::Constants::STATUS_DONE);   ## RETURN ##
        }

        push @data, $first;

        ## if there's nothing left in the iterator, return the single value.
        unless ($index < $max) {
            return \@data;
        }
    }

    # if there's still some data to go...
    if ($index < $max) {
        $index++;
        push @data, @{ $self->{ _DATASET } } [ $index..$max ];

        # update counters and flags
        @$self{ qw( INDEX COUNT FIRST LAST ) }
        = ( $max, $max + 1, 0, 1 );

        return \@data;                                      ## RETURN ##
    }
    else {
        return (undef, Template::Constants::STATUS_DONE);   ## RETURN ##
    }
}

sub odd {
    shift->{ COUNT } % 2 ? 1 : 0
}

sub even {
    shift->{ COUNT } % 2 ? 0 : 1
}

sub parity {
    shift->{ COUNT } % 2 ? ODD : EVEN;
}


#------------------------------------------------------------------------
# AUTOLOAD
#
# Provides access to internal fields (e.g. size, first, last, max, etc)
#------------------------------------------------------------------------

sub AUTOLOAD {
    my $self = shift;
    my $item = $AUTOLOAD;
    $item =~ s/.*:://;
    return if $item eq 'DESTROY';

    # alias NUMBER to COUNT for backwards compatibility
    $item = 'COUNT' if $item =~ /NUMBER/i;

    return $self->{ uc $item };
}


#========================================================================
#                   -----  PRIVATE DEBUG METHODS -----
#========================================================================

#------------------------------------------------------------------------
# _dump()
#
# Debug method which returns a string detailing the internal state of
# the iterator object.
#------------------------------------------------------------------------

sub _dump {
    my $self = shift;
    join('',
         "  Data: ", $self->{ _DATA  }, "\n",
         " Index: ", $self->{ INDEX  }, "\n",
         "Number: ", $self->{ NUMBER }, "\n",
         "   Max: ", $self->{ MAX    }, "\n",
         "  Size: ", $self->{ SIZE   }, "\n",
         " First: ", $self->{ FIRST  }, "\n",
         "  Last: ", $self->{ LAST   }, "\n",
         "\n"
     );
}


1;

__END__