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package CPAN::Meta::YAML;
{
  $CPAN::Meta::YAML::VERSION = '0.010';
}
BEGIN {
  $CPAN::Meta::YAML::AUTHORITY = 'cpan:ADAMK';
}
{
; # original $VERSION removed by Doppelgaenger
}
# git description: v1.54-8-g4c3002d


use strict;
use warnings;

# UTF Support?
sub HAVE_UTF8 () { $] >= 5.007003 }
BEGIN {
    if ( HAVE_UTF8 ) {
        # The string eval helps hide this from Test::MinimumVersion
        eval "require utf8;";
        die "Failed to load UTF-8 support" if $@;
    }

    # Class structure
    require 5.004;
    require Exporter;
    require Carp;
    @CPAN::Meta::YAML::ISA       = qw{ Exporter  };
    @CPAN::Meta::YAML::EXPORT    = qw{ Load Dump };
    @CPAN::Meta::YAML::EXPORT_OK = qw{ LoadFile DumpFile freeze thaw };

    # Error storage
    $CPAN::Meta::YAML::errstr    = '';
}

# The character class of all characters we need to escape
# NOTE: Inlined, since it's only used once
# my $RE_ESCAPE = '[\\x00-\\x08\\x0b-\\x0d\\x0e-\\x1f\"\n]';

# Printed form of the unprintable characters in the lowest range
# of ASCII characters, listed by ASCII ordinal position.
my @UNPRINTABLE = qw(
    z    x01  x02  x03  x04  x05  x06  a
    x08  t    n    v    f    r    x0e  x0f
    x10  x11  x12  x13  x14  x15  x16  x17
    x18  x19  x1a  e    x1c  x1d  x1e  x1f
);

# Printable characters for escapes
my %UNESCAPES = (
    z => "\x00", a => "\x07", t    => "\x09",
    n => "\x0a", v => "\x0b", f    => "\x0c",
    r => "\x0d", e => "\x1b", '\\' => '\\',
);

# Special magic boolean words
my %QUOTE = map { $_ => 1 } qw{
    null Null NULL
    y Y yes Yes YES n N no No NO
    true True TRUE false False FALSE
    on On ON off Off OFF
};





#####################################################################
# Implementation

# Create an empty CPAN::Meta::YAML object
sub new {
    my $class = shift;
    bless [ @_ ], $class;
}

# Create an object from a file
sub read {
    my $class = ref $_[0] ? ref shift : shift;

    # Check the file
    my $file = shift or return $class->_error( 'You did not specify a file name' );
    return $class->_error( "File '$file' does not exist" )              unless -e $file;
    return $class->_error( "'$file' is a directory, not a file" )       unless -f _;
    return $class->_error( "Insufficient permissions to read '$file'" ) unless -r _;

    # Slurp in the file
    local $/ = undef;
    local *CFG;
    unless ( open(CFG, $file) ) {
        return $class->_error("Failed to open file '$file': $!");
    }
    my $contents = <CFG>;
    unless ( close(CFG) ) {
        return $class->_error("Failed to close file '$file': $!");
    }

    $class->read_string( $contents );
}

# Create an object from a string
sub read_string {
    my $class  = ref $_[0] ? ref shift : shift;
    my $self   = bless [], $class;
    my $string = $_[0];
    eval {
        unless ( defined $string ) {
            die \"Did not provide a string to load";
        }

        # Byte order marks
        # NOTE: Keeping this here to educate maintainers
        # my %BOM = (
        #     "\357\273\277" => 'UTF-8',
        #     "\376\377"     => 'UTF-16BE',
        #     "\377\376"     => 'UTF-16LE',
        #     "\377\376\0\0" => 'UTF-32LE'
        #     "\0\0\376\377" => 'UTF-32BE',
        # );
        if ( $string =~ /^(?:\376\377|\377\376|\377\376\0\0|\0\0\376\377)/ ) {
            die \"Stream has a non UTF-8 BOM";
        } else {
            # Strip UTF-8 bom if found, we'll just ignore it
            $string =~ s/^\357\273\277//;
        }

        # Try to decode as utf8
        utf8::decode($string) if HAVE_UTF8;

        # Check for some special cases
        return $self unless length $string;
        unless ( $string =~ /[\012\015]+\z/ ) {
            die \"Stream does not end with newline character";
        }

        # Split the file into lines
        my @lines = grep { ! /^\s*(?:\#.*)?\z/ }
                split /(?:\015{1,2}\012|\015|\012)/, $string;

        # Strip the initial YAML header
        @lines and $lines[0] =~ /^\%YAML[: ][\d\.]+.*\z/ and shift @lines;

        # A nibbling parser
        while ( @lines ) {
            # Do we have a document header?
            if ( $lines[0] =~ /^---\s*(?:(.+)\s*)?\z/ ) {
                # Handle scalar documents
                shift @lines;
                if ( defined $1 and $1 !~ /^(?:\#.+|\%YAML[: ][\d\.]+)\z/ ) {
                    push @$self, $self->_read_scalar( "$1", [ undef ], \@lines );
                    next;
                }
            }

            if ( ! @lines or $lines[0] =~ /^(?:---|\.\.\.)/ ) {
                # A naked document
                push @$self, undef;
                while ( @lines and $lines[0] !~ /^---/ ) {
                    shift @lines;
                }

            } elsif ( $lines[0] =~ /^\s*\-/ ) {
                # An array at the root
                my $document = [ ];
                push @$self, $document;
                $self->_read_array( $document, [ 0 ], \@lines );

            } elsif ( $lines[0] =~ /^(\s*)\S/ ) {
                # A hash at the root
                my $document = { };
                push @$self, $document;
                $self->_read_hash( $document, [ length($1) ], \@lines );

            } else {
                die \"CPAN::Meta::YAML failed to classify the line '$lines[0]'";
            }
        }
    };
    if ( ref $@ eq 'SCALAR' ) {
        return $self->_error(${$@});
    } elsif ( $@ ) {
        require Carp;
        Carp::croak($@);
    }

    return $self;
}

# Deparse a scalar string to the actual scalar
sub _read_scalar {
    my ($self, $string, $indent, $lines) = @_;

    # Trim trailing whitespace
    $string =~ s/\s*\z//;

    # Explitic null/undef
    return undef if $string eq '~';

    # Single quote
    if ( $string =~ /^\'(.*?)\'(?:\s+\#.*)?\z/ ) {
        return '' unless defined $1;
        $string = $1;
        $string =~ s/\'\'/\'/g;
        return $string;
    }

    # Double quote.
    # The commented out form is simpler, but overloaded the Perl regex
    # engine due to recursion and backtracking problems on strings
    # larger than 32,000ish characters. Keep it for reference purposes.
    # if ( $string =~ /^\"((?:\\.|[^\"])*)\"\z/ ) {
    if ( $string =~ /^\"([^\\"]*(?:\\.[^\\"]*)*)\"(?:\s+\#.*)?\z/ ) {
        # Reusing the variable is a little ugly,
        # but avoids a new variable and a string copy.
        $string = $1;
        $string =~ s/\\"/"/g;
        $string =~ s/\\([never\\fartz]|x([0-9a-fA-F]{2}))/(length($1)>1)?pack("H2",$2):$UNESCAPES{$1}/gex;
        return $string;
    }

    # Special cases
    if ( $string =~ /^[\'\"!&]/ ) {
        die \"CPAN::Meta::YAML does not support a feature in line '$string'";
    }
    return {} if $string =~ /^{}(?:\s+\#.*)?\z/;
    return [] if $string =~ /^\[\](?:\s+\#.*)?\z/;

    # Regular unquoted string
    if ( $string !~ /^[>|]/ ) {
        if (
            $string =~ /^(?:-(?:\s|$)|[\@\%\`])/
            or
            $string =~ /:(?:\s|$)/
        ) {
            die \"CPAN::Meta::YAML found illegal characters in plain scalar: '$string'";
        }
        $string =~ s/\s+#.*\z//;
        return $string;
    }

    # Error
    die \"CPAN::Meta::YAML failed to find multi-line scalar content" unless @$lines;

    # Check the indent depth
    $lines->[0]   =~ /^(\s*)/;
    $indent->[-1] = length("$1");
    if ( defined $indent->[-2] and $indent->[-1] <= $indent->[-2] ) {
        die \"CPAN::Meta::YAML found bad indenting in line '$lines->[0]'";
    }

    # Pull the lines
    my @multiline = ();
    while ( @$lines ) {
        $lines->[0] =~ /^(\s*)/;
        last unless length($1) >= $indent->[-1];
        push @multiline, substr(shift(@$lines), length($1));
    }

    my $j = (substr($string, 0, 1) eq '>') ? ' ' : "\n";
    my $t = (substr($string, 1, 1) eq '-') ? ''  : "\n";
    return join( $j, @multiline ) . $t;
}

# Parse an array
sub _read_array {
    my ($self, $array, $indent, $lines) = @_;

    while ( @$lines ) {
        # Check for a new document
        if ( $lines->[0] =~ /^(?:---|\.\.\.)/ ) {
            while ( @$lines and $lines->[0] !~ /^---/ ) {
                shift @$lines;
            }
            return 1;
        }

        # Check the indent level
        $lines->[0] =~ /^(\s*)/;
        if ( length($1) < $indent->[-1] ) {
            return 1;
        } elsif ( length($1) > $indent->[-1] ) {
            die \"CPAN::Meta::YAML found bad indenting in line '$lines->[0]'";
        }

        if ( $lines->[0] =~ /^(\s*\-\s+)[^\'\"]\S*\s*:(?:\s+|$)/ ) {
            # Inline nested hash
            my $indent2 = length("$1");
            $lines->[0] =~ s/-/ /;
            push @$array, { };
            $self->_read_hash( $array->[-1], [ @$indent, $indent2 ], $lines );

        } elsif ( $lines->[0] =~ /^\s*\-(\s*)(.+?)\s*\z/ ) {
            # Array entry with a value
            shift @$lines;
            push @$array, $self->_read_scalar( "$2", [ @$indent, undef ], $lines );

        } elsif ( $lines->[0] =~ /^\s*\-\s*\z/ ) {
            shift @$lines;
            unless ( @$lines ) {
                push @$array, undef;
                return 1;
            }
            if ( $lines->[0] =~ /^(\s*)\-/ ) {
                my $indent2 = length("$1");
                if ( $indent->[-1] == $indent2 ) {
                    # Null array entry
                    push @$array, undef;
                } else {
                    # Naked indenter
                    push @$array, [ ];
                    $self->_read_array( $array->[-1], [ @$indent, $indent2 ], $lines );
                }

            } elsif ( $lines->[0] =~ /^(\s*)\S/ ) {
                push @$array, { };
                $self->_read_hash( $array->[-1], [ @$indent, length("$1") ], $lines );

            } else {
                die \"CPAN::Meta::YAML failed to classify line '$lines->[0]'";
            }

        } elsif ( defined $indent->[-2] and $indent->[-1] == $indent->[-2] ) {
            # This is probably a structure like the following...
            # ---
            # foo:
            # - list
            # bar: value
            #
            # ... so lets return and let the hash parser handle it
            return 1;

        } else {
            die \"CPAN::Meta::YAML failed to classify line '$lines->[0]'";
        }
    }

    return 1;
}

# Parse an array
sub _read_hash {
    my ($self, $hash, $indent, $lines) = @_;

    while ( @$lines ) {
        # Check for a new document
        if ( $lines->[0] =~ /^(?:---|\.\.\.)/ ) {
            while ( @$lines and $lines->[0] !~ /^---/ ) {
                shift @$lines;
            }
            return 1;
        }

        # Check the indent level
        $lines->[0] =~ /^(\s*)/;
        if ( length($1) < $indent->[-1] ) {
            return 1;
        } elsif ( length($1) > $indent->[-1] ) {
            die \"CPAN::Meta::YAML found bad indenting in line '$lines->[0]'";
        }

        # Get the key
        unless ( $lines->[0] =~ s/^\s*([^\'\" ][^\n]*?)\s*:(\s+(?:\#.*)?|$)// ) {
            if ( $lines->[0] =~ /^\s*[?\'\"]/ ) {
                die \"CPAN::Meta::YAML does not support a feature in line '$lines->[0]'";
            }
            die \"CPAN::Meta::YAML failed to classify line '$lines->[0]'";
        }
        my $key = $1;

        # Do we have a value?
        if ( length $lines->[0] ) {
            # Yes
            $hash->{$key} = $self->_read_scalar( shift(@$lines), [ @$indent, undef ], $lines );
        } else {
            # An indent
            shift @$lines;
            unless ( @$lines ) {
                $hash->{$key} = undef;
                return 1;
            }
            if ( $lines->[0] =~ /^(\s*)-/ ) {
                $hash->{$key} = [];
                $self->_read_array( $hash->{$key}, [ @$indent, length($1) ], $lines );
            } elsif ( $lines->[0] =~ /^(\s*)./ ) {
                my $indent2 = length("$1");
                if ( $indent->[-1] >= $indent2 ) {
                    # Null hash entry
                    $hash->{$key} = undef;
                } else {
                    $hash->{$key} = {};
                    $self->_read_hash( $hash->{$key}, [ @$indent, length($1) ], $lines );
                }
            }
        }
    }

    return 1;
}

# Save an object to a file
sub write {
    my $self = shift;
    my $file = shift or return $self->_error('No file name provided');

    # Write it to the file
    open( CFG, '>' . $file ) or return $self->_error(
        "Failed to open file '$file' for writing: $!"
        );
    print CFG $self->write_string;
    close CFG;

    return 1;
}

# Save an object to a string
sub write_string {
    my $self = shift;
    return '' unless @$self;

    # Iterate over the documents
    my $indent = 0;
    my @lines  = ();
    foreach my $cursor ( @$self ) {
        push @lines, '---';

        # An empty document
        if ( ! defined $cursor ) {
            # Do nothing

        # A scalar document
        } elsif ( ! ref $cursor ) {
            $lines[-1] .= ' ' . $self->_write_scalar( $cursor, $indent );

        # A list at the root
        } elsif ( ref $cursor eq 'ARRAY' ) {
            unless ( @$cursor ) {
                $lines[-1] .= ' []';
                next;
            }
            push @lines, $self->_write_array( $cursor, $indent, {} );

        # A hash at the root
        } elsif ( ref $cursor eq 'HASH' ) {
            unless ( %$cursor ) {
                $lines[-1] .= ' {}';
                next;
            }
            push @lines, $self->_write_hash( $cursor, $indent, {} );

        } else {
            Carp::croak("Cannot serialize " . ref($cursor));
        }
    }

    join '', map { "$_\n" } @lines;
}

sub _write_scalar {
    my $string = $_[1];
    return '~'  unless defined $string;
    return "''" unless length  $string;
    if ( $string =~ /[\x00-\x08\x0b-\x0d\x0e-\x1f\"\'\n]/ ) {
        $string =~ s/\\/\\\\/g;
        $string =~ s/"/\\"/g;
        $string =~ s/\n/\\n/g;
        $string =~ s/([\x00-\x1f])/\\$UNPRINTABLE[ord($1)]/g;
        return qq|"$string"|;
    }
    if ( $string =~ /(?:^\W|\s|:\z)/ or $QUOTE{$string} ) {
        return "'$string'";
    }
    return $string;
}

sub _write_array {
    my ($self, $array, $indent, $seen) = @_;
    if ( $seen->{refaddr($array)}++ ) {
        die "CPAN::Meta::YAML does not support circular references";
    }
    my @lines  = ();
    foreach my $el ( @$array ) {
        my $line = ('  ' x $indent) . '-';
        my $type = ref $el;
        if ( ! $type ) {
            $line .= ' ' . $self->_write_scalar( $el, $indent + 1 );
            push @lines, $line;

        } elsif ( $type eq 'ARRAY' ) {
            if ( @$el ) {
                push @lines, $line;
                push @lines, $self->_write_array( $el, $indent + 1, $seen );
            } else {
                $line .= ' []';
                push @lines, $line;
            }

        } elsif ( $type eq 'HASH' ) {
            if ( keys %$el ) {
                push @lines, $line;
                push @lines, $self->_write_hash( $el, $indent + 1, $seen );
            } else {
                $line .= ' {}';
                push @lines, $line;
            }

        } else {
            die "CPAN::Meta::YAML does not support $type references";
        }
    }

    @lines;
}

sub _write_hash {
    my ($self, $hash, $indent, $seen) = @_;
    if ( $seen->{refaddr($hash)}++ ) {
        die "CPAN::Meta::YAML does not support circular references";
    }
    my @lines  = ();
    foreach my $name ( sort keys %$hash ) {
        my $el   = $hash->{$name};
        my $line = ('  ' x $indent) . "$name:";
        my $type = ref $el;
        if ( ! $type ) {
            $line .= ' ' . $self->_write_scalar( $el, $indent + 1 );
            push @lines, $line;

        } elsif ( $type eq 'ARRAY' ) {
            if ( @$el ) {
                push @lines, $line;
                push @lines, $self->_write_array( $el, $indent + 1, $seen );
            } else {
                $line .= ' []';
                push @lines, $line;
            }

        } elsif ( $type eq 'HASH' ) {
            if ( keys %$el ) {
                push @lines, $line;
                push @lines, $self->_write_hash( $el, $indent + 1, $seen );
            } else {
                $line .= ' {}';
                push @lines, $line;
            }

        } else {
            die "CPAN::Meta::YAML does not support $type references";
        }
    }

    @lines;
}

# Set error
sub _error {
    $CPAN::Meta::YAML::errstr = $_[1];
    undef;
}

# Retrieve error
sub errstr {
    $CPAN::Meta::YAML::errstr;
}





#####################################################################
# YAML Compatibility

sub Dump {
    CPAN::Meta::YAML->new(@_)->write_string;
}

sub Load {
    my $self = CPAN::Meta::YAML->read_string(@_);
    unless ( $self ) {
        Carp::croak("Failed to load YAML document from string");
    }
    if ( wantarray ) {
        return @$self;
    } else {
        # To match YAML.pm, return the last document
        return $self->[-1];
    }
}

BEGIN {
    *freeze = *Dump;
    *thaw   = *Load;
}

sub DumpFile {
    my $file = shift;
    CPAN::Meta::YAML->new(@_)->write($file);
}

sub LoadFile {
    my $self = CPAN::Meta::YAML->read($_[0]);
    unless ( $self ) {
        Carp::croak("Failed to load YAML document from '" . ($_[0] || '') . "'");
    }
    if ( wantarray ) {
        return @$self;
    } else {
        # Return only the last document to match YAML.pm,
        return $self->[-1];
    }
}





#####################################################################
# Use Scalar::Util if possible, otherwise emulate it

BEGIN {
    local $@;
    eval {
        require Scalar::Util;
    };
    my $v = eval("$Scalar::Util::VERSION") || 0;
    if ( $@ or $v < 1.18 ) {
        eval <<'END_PERL';
# Scalar::Util failed to load or too old
sub refaddr {
    my $pkg = ref($_[0]) or return undef;
    if ( !! UNIVERSAL::can($_[0], 'can') ) {
        bless $_[0], 'Scalar::Util::Fake';
    } else {
        $pkg = undef;
    }
    "$_[0]" =~ /0x(\w+)/;
    my $i = do { local $^W; hex $1 };
    bless $_[0], $pkg if defined $pkg;
    $i;
}
END_PERL
    } else {
        *refaddr = *Scalar::Util::refaddr;
    }
}

1;

=pod

=encoding utf-8

=head1 NAME

CPAN::Meta::YAML - Read and write a subset of YAML for CPAN Meta files

=head1 VERSION

version 0.010

=head1 SYNOPSIS

    use CPAN::Meta::YAML;

    # reading a META file
    open $fh, "<:utf8", "META.yml";
    $yaml_text = do { local $/; <$fh> };
    $yaml = CPAN::Meta::YAML->read_string($yaml_text)
      or die CPAN::Meta::YAML->errstr;

    # finding the metadata
    $meta = $yaml->[0];

    # writing a META file
    $yaml_text = $yaml->write_string
      or die CPAN::Meta::YAML->errstr;
    open $fh, ">:utf8", "META.yml";
    print $fh $yaml_text;

=head1 DESCRIPTION

This module implements a subset of the YAML specification for use in reading
and writing CPAN metadata files like F<META.yml> and F<MYMETA.yml>.  It should
not be used for any other general YAML parsing or generation task.

NOTE: F<META.yml> (and F<MYMETA.yml>) files should be UTF-8 encoded.  Users are
responsible for proper encoding and decoding.  In particular, the C<read> and
C<write> methods do B<not> support UTF-8 and should not be used.

=head1 SUPPORT

This module is currently derived from L<YAML::Tiny> by Adam Kennedy.  If
there are bugs in how it parses a particular META.yml file, please file
a bug report in the YAML::Tiny bugtracker:
L<https://rt.cpan.org/Public/Dist/Display.html?Name=YAML-Tiny>

=head1 SEE ALSO

L<YAML::Tiny>, L<YAML>, L<YAML::XS>

=for :stopwords cpan testmatrix url annocpan anno bugtracker rt cpants kwalitee diff irc mailto metadata placeholders metacpan

=head1 SUPPORT

=head2 Bugs / Feature Requests

Please report any bugs or feature requests through the issue tracker
at L<https://github.com/dagolden/CPAN-Meta-YAML/issues>.
You will be notified automatically of any progress on your issue.

=head2 Source Code

This is open source software.  The code repository is available for
public review and contribution under the terms of the license.

L<https://github.com/dagolden/CPAN-Meta-YAML>

  git clone https://github.com/dagolden/CPAN-Meta-YAML.git

=head1 AUTHORS

=over 4

=item *

Adam Kennedy <adamk@cpan.org>

=item *

David Golden <dagolden@cpan.org>

=back

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2010 by Adam Kennedy.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut

__END__


# ABSTRACT: Read and write a subset of YAML for CPAN Meta files