diff options
Diffstat (limited to 'lib/Exporter/Heavy.pm')
| -rw-r--r-- | lib/Exporter/Heavy.pm | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/lib/Exporter/Heavy.pm b/lib/Exporter/Heavy.pm new file mode 100644 index 0000000000..f049e72ea9 --- /dev/null +++ b/lib/Exporter/Heavy.pm @@ -0,0 +1,223 @@ +package Exporter; + +=head1 NAME + +Exporter::Heavy - Exporter guts + +=head1 SYNOPIS + +(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 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, $oops); + *exports = *{"${pkg}::EXPORT"}; + + if (@imports) { + if (!%exports) { + grep(s/^&//, @exports); + @exports{@exports} = (1) x @exports; + my $ok = \@{"${pkg}::EXPORT_OK"}; + if (@$ok) { + grep(s/^&//, @$ok); + @exports{@$ok} = (1) x @$ok; + } + } + + if ($imports[0] =~ m#^[/!:]#){ + 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 = $1; + @allexports = keys %exports unless @allexports; # only do keys once + @names = grep(/$patn/, @allexports); # not anchored by default + } + else { + @names = ($spec); # is a normal symbol name + } + + warn "Import ".($remove ? "del":"add").": @names " + if $Verbose; + + if ($remove) { + foreach $sym (@names) { delete $imports{$sym} } + } + else { + @imports{@names} = (1) x @names; + } + } + @imports = keys %imports; + } + + foreach $sym (@imports) { + if (!$exports{$sym}) { + if ($sym =~ m/^\d/) { + $pkg->require_version($sym); + # 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/^&// || !$exports{$sym}) { + require Carp; + Carp::carp(qq["$sym" is not exported by the $pkg module]); + $oops++; + } + } + } + if ($oops) { + require Carp; + Carp::croak("Can't continue after import errors"); + } + } + else { + @imports = @exports; + } + + *fail = *{"${pkg}::EXPORT_FAIL"}; + if (@fail) { + if (!%fail) { + # Build cache of symbols. Optimise the lookup by adding + # barewords twice... both with and without a leading &. + # (Technique could be applied to %exports cache at cost of memory) + my @expanded = map { /^\w/ ? ($_, '&'.$_) : $_ } @fail; + warn "${pkg}::EXPORT_FAIL cached: @expanded" if $Verbose; + @fail{@expanded} = (1) x @expanded; + } + my @failed; + foreach $sym (@imports) { push(@failed, $sym) if $fail{$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 $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; + my $callpkg = caller($level); + $pkg->export($callpkg, @_); +} + +# Utility functions + +sub _push_tags { + my($pkg, $var, $syms) = @_; + my $nontag; + *export_tags = \%{"${pkg}::EXPORT_TAGS"}; + push(@{"${pkg}::$var"}, + map { $export_tags{$_} ? @{$export_tags{$_}} : scalar(++$nontag,$_) } + (@$syms) ? @$syms : keys %export_tags); + if ($nontag and $^W) { + # This may change to a die one day + require Carp; + Carp::carp("Some names are not tags"); + } +} + +# Default methods + +sub export_fail { + my $self = shift; + @_; +} + +sub require_version { + my($self, $wanted) = @_; + my $pkg = ref $self || $self; + my $version = ${"${pkg}::VERSION"}; + if (!$version or $version < $wanted) { + $version ||= "(undef)"; + my $file = $INC{"$pkg.pm"}; + $file &&= " ($file)"; + require Carp; + Carp::croak("$pkg $wanted required--this is only version $version$file") + } + $version; +} + +1; |