—

              
package Exporter::Heavy;
use strict;
no strict 'refs';
# On one line so MakeMaker will see it.
our $VERSION = '5.78';
HideShow 14 lines of Pod
=head1 NAME
Exporter::Heavy - Exporter guts
=head1 SYNOPSIS
(internal use only)
=head1 DESCRIPTION
No user-serviceable parts inside.
=cut
#
# We go to a lot of trouble not to 'require Carp' at file scope,
#  because Carp requires Exporter, and something has to give.
#
sub _rebuild_cache {
    my ($pkg, $exports, $cache) = @_;
    s/^&// foreach @$exports;
    @{$cache}{@$exports} = (1) x @$exports;
    my $ok = \@{"${pkg}::EXPORT_OK"};
    if (@$ok) {
        s/^&// foreach @$ok;
        @{$cache}{@$ok} = (1) x @$ok;
    }
}
sub heavy_export {
    # Save the old __WARN__ handler in case it was defined
    my $oldwarn = $SIG{__WARN__};
    # First make import warnings look like they're coming from the "use".
    local $SIG{__WARN__} = sub {
        # restore it back so proper stacking occurs
        local $SIG{__WARN__} = $oldwarn;
        my $text = shift;
        if ($text =~ s/ at \S*Exporter\S*.pm line \d+.*\n//) {
            require Carp;
            local $Carp::CarpLevel = 1; # ignore package calling us too.
            Carp::carp($text);
        }
        else {
            warn $text;
        }
    };
    local $SIG{__DIE__} = sub {
        require Carp;
        local $Carp::CarpLevel = 1;     # ignore package calling us too.
        Carp::croak("$_[0]Illegal null symbol in \@${1}::EXPORT")
            if $_[0] =~ /^Unable to create sub named "(.*?)::"/;
    };
    my($pkg, $callpkg, @imports) = @_;
    my($type, $sym, $cache_is_current, $oops);
    my($exports, $export_cache) = (\@{"${pkg}::EXPORT"},
                                   $Exporter::Cache{$pkg} ||= {});
    if (@imports) {
        if (!%$export_cache) {
            _rebuild_cache ($pkg, $exports, $export_cache);
            $cache_is_current = 1;
        }
        if (grep m{^[/!:]}, @imports) {
            my $tagsref = \%{"${pkg}::EXPORT_TAGS"};
            my $tagdata;
            my %imports;
            my($remove, $spec, @names, @allexports);
            # negated first item implies starting with default set:
            unshift @imports, ':DEFAULT' if $imports[0] =~ m/^!/;
            foreach $spec (@imports){
                $remove = $spec =~ s/^!//;
                if ($spec =~ s/^://){
                    if ($spec eq 'DEFAULT'){
                        @names = @$exports;
                    }
                    elsif ($tagdata = $tagsref->{$spec}) {
                        @names = @$tagdata;
                    }
                    else {
                        warn qq["$spec" is not defined in %${pkg}::EXPORT_TAGS];
                        ++$oops;
                        next;
                    }
                }
                elsif ($spec =~ m:^/(.*)/$:){
                    my $patn = $1;
                    @allexports = keys %$export_cache unless @allexports; # only do keys once
                    @names = grep(/$patn/, @allexports); # not anchored by default
                }
                else {
                    @names = ($spec); # is a normal symbol name
                }
                warn "Import ".($remove ? "del":"add").": @names "
                    if $Exporter::Verbose;
                if ($remove) {
                   foreach $sym (@names) { delete $imports{$sym} } 
                }
                else {
                    @imports{@names} = (1) x @names;
                }
            }
            @imports = keys %imports;
        }
        my @carp;
        foreach $sym (@imports) {
            if (!$export_cache->{$sym}) {
                if ($sym =~ m/^\d/) {
                    $pkg->VERSION($sym); # inherit from UNIVERSAL
                    # If the version number was the only thing specified
                    # then we should act as if nothing was specified:
                    if (@imports == 1) {
                        @imports = @$exports;
                        last;
                    }
                    # We need a way to emulate 'use Foo ()' but still
                    # allow an easy version check: "use Foo 1.23, ''";
                    if (@imports == 2 and !$imports[1]) {
                        @imports = ();
                        last;
                    }
                } elsif ($sym !~ s/^&// || !$export_cache->{$sym}) {
                    # Last chance - see if they've updated EXPORT_OK since we
                    # cached it.
                    unless ($cache_is_current) {
                        %$export_cache = ();
                        _rebuild_cache ($pkg, $exports, $export_cache);
                        $cache_is_current = 1;
                    }
                    if (!$export_cache->{$sym}) {
                        # accumulate the non-exports
                        push @carp,
                          qq["$sym" is not exported by the $pkg module];
                        $oops++;
                    }
                }
            }
        }
        if ($oops) {
            require Carp;
            Carp::croak(join("\n", @carp, "Can't continue after import errors"));
        }
    }
    else {
        @imports = @$exports;
    }
    my($fail, $fail_cache) = (\@{"${pkg}::EXPORT_FAIL"},
                              $Exporter::FailCache{$pkg} ||= {});
    if (@$fail) {
        if (!%$fail_cache) {
            # Build cache of symbols. Optimise the lookup by adding
            # barewords twice... both with and without a leading &.
            # (Technique could be applied to $export_cache at cost of memory)
            my @expanded = map { /^\w/ ? ($_, '&'.$_) : $_ } @$fail;
            warn "${pkg}::EXPORT_FAIL cached: @expanded" if $Exporter::Verbose;
            @{$fail_cache}{@expanded} = (1) x @expanded;
        }
        my @failed;
        foreach $sym (@imports) { push(@failed, $sym) if $fail_cache->{$sym} }
        if (@failed) {
            @failed = $pkg->export_fail(@failed);
            foreach $sym (@failed) {
                require Carp;
                Carp::carp(qq["$sym" is not implemented by the $pkg module ],
                        "on this architecture");
            }
            if (@failed) {
                require Carp;
                Carp::croak("Can't continue after import errors");
            }
        }
    }
    warn "Importing into $callpkg from $pkg: ",
                join(", ",sort @imports) if $Exporter::Verbose;
    foreach $sym (@imports) {
        # shortcut for the common case of no type character
        (*{"${callpkg}::$sym"} = \&{"${pkg}::$sym"}, next)
            unless $sym =~ s/^(\W)//;
        $type = $1;
        no warnings 'once';
        *{"${callpkg}::$sym"} =
            $type eq '&' ? \&{"${pkg}::$sym"} :
            $type eq '$' ? \${"${pkg}::$sym"} :
            $type eq '@' ? \@{"${pkg}::$sym"} :
            $type eq '%' ? \%{"${pkg}::$sym"} :
            $type eq '*' ?  *{"${pkg}::$sym"} :
            do { require Carp; Carp::croak("Can't export symbol: $type$sym") };
    }
}
sub heavy_export_to_level
{
      my $pkg = shift;
      my $level = shift;
      (undef) = shift;                  # XXX redundant arg
      my $callpkg = caller($level);
      $pkg->export($callpkg, @_);
}
# Utility functions
sub _push_tags {
    my($pkg, $var, $syms) = @_;
    my @nontag = ();
    my $export_tags = \%{"${pkg}::EXPORT_TAGS"};
    push(@{"${pkg}::$var"},
        map { $export_tags->{$_} ? @{$export_tags->{$_}} 
                                 : scalar(push(@nontag,$_),$_) }
                (@$syms) ? @$syms : keys %$export_tags);
    if (@nontag and $^W) {
        # This may change to a die one day
        require Carp;
        Carp::carp(join(", ", @nontag)." are not tags of $pkg");
    }
}
sub heavy_require_version {
    my($self, $wanted) = @_;
    my $pkg = ref $self || $self;
    return ${pkg}->VERSION($wanted);
}
sub heavy_export_tags {
  _push_tags((caller)[0], "EXPORT",    \@_);
}
sub heavy_export_ok_tags {
  _push_tags((caller)[0], "EXPORT_OK", \@_);
}
1;