source: for-distributions/trunk/bin/windows/perl/lib/Exporter/Heavy.pm@ 14489

package Exporter::Heavy;

use strict;
no strict 'refs';

# On one line so MakeMaker will see it.
require Exporter;  our $VERSION = $Exporter::VERSION;
$Carp::Internal{"Exporter::Heavy"} = 1;

=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 {

    # First make import warnings look like they're coming from the "use".
    local $SIG{__WARN__} = sub {
    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\n];
            $oops++;
            }
        }
        }
    }
    if ($oops) {
        require Carp;
        Carp::croak("@{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 = $1;
    *{"${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;