1: package Exporter::Heavy;
2: 
3: use strict;
4: no strict 'refs';
5: 
6: # On one line so MakeMaker will see it.
7: require Exporter;  our $VERSION = $Exporter::VERSION;
8: 
9: # Carp 1.05+ does this now for us, but we may be running with an old Carp
10: $Carp::Internal{'Exporter::Heavy'}++;
11: 
12: =head1 NAME
13: 
14: Exporter::Heavy - Exporter guts
15: 
16: =head1 SYNOPSIS
17: 
18: (internal use only)
19: 
20: =head1 DESCRIPTION
21: 
22: No user-serviceable parts inside.
23: 
24: =cut
25: 
26: #
27: # We go to a lot of trouble not to 'require Carp' at file scope,
28: #  because Carp requires Exporter, and something has to give.
29: #
30: 
31: sub _rebuild_cache {
32:     my ($pkg, $exports, $cache) = @_;
33:     s/^&// foreach @$exports;
34:     @{$cache}{@$exports} = (1) x @$exports;
35:     my $ok = \@{"${pkg}::EXPORT_OK"};
36:     if (@$ok) {
37: 	s/^&// foreach @$ok;
38: 	@{$cache}{@$ok} = (1) x @$ok;
39:     }
40: }
41: 
42: sub heavy_export {
43: 
44:     # First make import warnings look like they're coming from the "use".
45:     local $SIG{__WARN__} = sub {
46: 	my $text = shift;
47: 	if ($text =~ s/ at \S*Exporter\S*.pm line \d+.*\n//) {
48: 	    require Carp;
49: 	    local $Carp::CarpLevel = 1;	# ignore package calling us too.
50: 	    Carp::carp($text);
51: 	}
52: 	else {
53: 	    warn $text;
54: 	}
55:     };
56:     local $SIG{__DIE__} = sub {
57: 	require Carp;
58: 	local $Carp::CarpLevel = 1;	# ignore package calling us too.
59: 	Carp::croak("$_[0]Illegal null symbol in \@${1}::EXPORT")
60: 	    if $_[0] =~ /^Unable to create sub named "(.*?)::"/;
61:     };
62: 
63:     my($pkg, $callpkg, @imports) = @_;
64:     my($type, $sym, $cache_is_current, $oops);
65:     my($exports, $export_cache) = (\@{"${pkg}::EXPORT"},
66:                                    $Exporter::Cache{$pkg} ||= {});
67: 
68:     if (@imports) {
69: 	if (!%$export_cache) {
70: 	    _rebuild_cache ($pkg, $exports, $export_cache);
71: 	    $cache_is_current = 1;
72: 	}
73: 
74: 	if (grep m{^[/!:]}, @imports) {
75: 	    my $tagsref = \%{"${pkg}::EXPORT_TAGS"};
76: 	    my $tagdata;
77: 	    my %imports;
78: 	    my($remove, $spec, @names, @allexports);
79: 	    # negated first item implies starting with default set:
80: 	    unshift @imports, ':DEFAULT' if $imports[0] =~ m/^!/;
81: 	    foreach $spec (@imports){
82: 		$remove = $spec =~ s/^!//;
83: 
84: 		if ($spec =~ s/^://){
85: 		    if ($spec eq 'DEFAULT'){
86: 			@names = @$exports;
87: 		    }
88: 		    elsif ($tagdata = $tagsref->{$spec}) {
89: 			@names = @$tagdata;
90: 		    }
91: 		    else {
92: 			warn qq["$spec" is not defined in %${pkg}::EXPORT_TAGS];
93: 			++$oops;
94: 			next;
95: 		    }
96: 		}
97: 		elsif ($spec =~ m:^/(.*)/$:){
98: 		    my $patn = $1;
99: 		    @allexports = keys %$export_cache unless @allexports; # only do keys once
100: 		    @names = grep(/$patn/, @allexports); # not anchored by default
101: 		}
102: 		else {
103: 		    @names = ($spec); # is a normal symbol name
104: 		}
105: 
106: 		warn "Import ".($remove ? "del":"add").": @names "
107: 		    if $Exporter::Verbose;
108: 
109: 		if ($remove) {
110: 		   foreach $sym (@names) { delete $imports{$sym} } 
111: 		}
112: 		else {
113: 		    @imports{@names} = (1) x @names;
114: 		}
115: 	    }
116: 	    @imports = keys %imports;
117: 	}
118: 
119:         my @carp;
120: 	foreach $sym (@imports) {
121: 	    if (!$export_cache->{$sym}) {
122: 		if ($sym =~ m/^\d/) {
123: 		    $pkg->VERSION($sym); # inherit from UNIVERSAL
124: 		    # If the version number was the only thing specified
125: 		    # then we should act as if nothing was specified:
126: 		    if (@imports == 1) {
127: 			@imports = @$exports;
128: 			last;
129: 		    }
130: 		    # We need a way to emulate 'use Foo ()' but still
131: 		    # allow an easy version check: "use Foo 1.23, ''";
132: 		    if (@imports == 2 and !$imports[1]) {
133: 			@imports = ();
134: 			last;
135: 		    }
136: 		} elsif ($sym !~ s/^&// || !$export_cache->{$sym}) {
137: 		    # Last chance - see if they've updated EXPORT_OK since we
138: 		    # cached it.
139: 
140: 		    unless ($cache_is_current) {
141: 			%$export_cache = ();
142: 			_rebuild_cache ($pkg, $exports, $export_cache);
143: 			$cache_is_current = 1;
144: 		    }
145: 
146: 		    if (!$export_cache->{$sym}) {
147: 			# accumulate the non-exports
148: 			push @carp,
149: 			  qq["$sym" is not exported by the $pkg module\n];
150: 			$oops++;
151: 		    }
152: 		}
153: 	    }
154: 	}
155: 	if ($oops) {
156: 	    require Carp;
157: 	    Carp::croak("@{carp}Can't continue after import errors");
158: 	}
159:     }
160:     else {
161: 	@imports = @$exports;
162:     }
163: 
164:     my($fail, $fail_cache) = (\@{"${pkg}::EXPORT_FAIL"},
165:                               $Exporter::FailCache{$pkg} ||= {});
166: 
167:     if (@$fail) {
168: 	if (!%$fail_cache) {
169: 	    # Build cache of symbols. Optimise the lookup by adding
170: 	    # barewords twice... both with and without a leading &.
171: 	    # (Technique could be applied to $export_cache at cost of memory)
172: 	    my @expanded = map { /^\w/ ? ($_, '&'.$_) : $_ } @$fail;
173: 	    warn "${pkg}::EXPORT_FAIL cached: @expanded" if $Exporter::Verbose;
174: 	    @{$fail_cache}{@expanded} = (1) x @expanded;
175: 	}
176: 	my @failed;
177: 	foreach $sym (@imports) { push(@failed, $sym) if $fail_cache->{$sym} }
178: 	if (@failed) {
179: 	    @failed = $pkg->export_fail(@failed);
180: 	    foreach $sym (@failed) {
181:                 require Carp;
182: 		Carp::carp(qq["$sym" is not implemented by the $pkg module ],
183: 			"on this architecture");
184: 	    }
185: 	    if (@failed) {
186: 		require Carp;
187: 		Carp::croak("Can't continue after import errors");
188: 	    }
189: 	}
190:     }
191: 
192:     warn "Importing into $callpkg from $pkg: ",
193: 		join(", ",sort @imports) if $Exporter::Verbose;
194: 
195:     foreach $sym (@imports) {
196: 	# shortcut for the common case of no type character
197: 	(*{"${callpkg}::$sym"} = \&{"${pkg}::$sym"}, next)
198: 	    unless $sym =~ s/^(\W)//;
199: 	$type = $1;
200: 	no warnings 'once';
201: 	*{"${callpkg}::$sym"} =
202: 	    $type eq '&' ? \&{"${pkg}::$sym"} :
203: 	    $type eq '$' ? \${"${pkg}::$sym"} :
204: 	    $type eq '@' ? \@{"${pkg}::$sym"} :
205: 	    $type eq '%' ? \%{"${pkg}::$sym"} :
206: 	    $type eq '*' ?  *{"${pkg}::$sym"} :
207: 	    do { require Carp; Carp::croak("Can't export symbol: $type$sym") };
208:     }
209: }
210: 
211: sub heavy_export_to_level
212: {
213:       my $pkg = shift;
214:       my $level = shift;
215:       (undef) = shift;			# XXX redundant arg
216:       my $callpkg = caller($level);
217:       $pkg->export($callpkg, @_);
218: }
219: 
220: # Utility functions
221: 
222: sub _push_tags {
223:     my($pkg, $var, $syms) = @_;
224:     my @nontag = ();
225:     my $export_tags = \%{"${pkg}::EXPORT_TAGS"};
226:     push(@{"${pkg}::$var"},
227: 	map { $export_tags->{$_} ? @{$export_tags->{$_}} 
228:                                  : scalar(push(@nontag,$_),$_) }
229: 		(@$syms) ? @$syms : keys %$export_tags);
230:     if (@nontag and $^W) {
231: 	# This may change to a die one day
232: 	require Carp;
233: 	Carp::carp(join(", ", @nontag)." are not tags of $pkg");
234:     }
235: }
236: 
237: sub heavy_require_version {
238:     my($self, $wanted) = @_;
239:     my $pkg = ref $self || $self;
240:     return ${pkg}->VERSION($wanted);
241: }
242: 
243: sub heavy_export_tags {
244:   _push_tags((caller)[0], "EXPORT",    \@_);
245: }
246: 
247: sub heavy_export_ok_tags {
248:   _push_tags((caller)[0], "EXPORT_OK", \@_);
249: }
250: 
251: 1;