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ab3370e7 |
1 | package Role::Tiny; |
2 | |
3 | use strictures 1; |
4 | use Class::Method::Modifiers (); |
5 | |
6 | our %INFO; |
7 | our %APPLIED_TO; |
8 | |
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9 | sub _getglob { no strict 'refs'; \*{$_[0]} } |
10 | |
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11 | sub import { |
12 | my $target = caller; |
13 | # get symbol table reference |
14 | my $stash = do { no strict 'refs'; \%{"${target}::"} }; |
15 | # install before/after/around subs |
16 | foreach my $type (qw(before after around)) { |
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17 | *{_getglob "${target}::${type}"} = sub { |
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18 | push @{$INFO{$target}{modifiers}||=[]}, [ $type => @_ ]; |
19 | }; |
20 | } |
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21 | *{_getglob "${target}::requires"} = sub { |
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22 | push @{$INFO{$target}{requires}||=[]}, @_; |
23 | }; |
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24 | *{_getglob "${target}::with"} = sub { |
25 | die "Only one role supported at a time by with" if @_ > 1; |
26 | Role::Tiny->apply_role_to_package($_[0], $target); |
27 | }; |
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28 | # grab all *non-constant* (ref eq 'SCALAR') subs present |
29 | # in the symbol table and store their refaddrs (no need to forcibly |
30 | # inflate constant subs into real subs) - also add '' to here (this |
31 | # is used later) |
32 | @{$INFO{$target}{not_methods}={}}{ |
33 | '', map { *$_{CODE}||() } grep !(ref eq 'SCALAR'), values %$stash |
34 | } = (); |
35 | # a role does itself |
36 | $APPLIED_TO{$target} = { $target => undef }; |
37 | } |
38 | |
39 | sub apply_role_to_package { |
40 | my ($class, $role, $to) = @_; |
41 | die "This is apply_role_to_package" if ref($to); |
42 | die "Not a Role::Tiny" unless my $info = $INFO{$role}; |
43 | my $methods = $info->{methods} ||= do { |
44 | # grab role symbol table |
45 | my $stash = do { no strict 'refs'; \%{"${role}::"}}; |
46 | my $not_methods = $info->{not_methods}; |
47 | +{ |
48 | # grab all code entries that aren't in the not_methods list |
49 | map { |
50 | my $code = *{$stash->{$_}}{CODE}; |
51 | # rely on the '' key we added in import for "no code here" |
52 | exists $not_methods->{$code||''} ? () : ($_ => $code) |
53 | } grep !(ref($stash->{$_}) eq 'SCALAR'), keys %$stash |
54 | }; |
55 | }; |
56 | # grab target symbol table |
57 | my $stash = do { no strict 'refs'; \%{"${to}::"}}; |
58 | # determine already extant methods of target |
59 | my %has_methods; |
60 | @has_methods{grep |
61 | +((ref($stash->{$_}) eq 'SCALAR') || (*{$stash->{$_}}{CODE})), |
62 | keys %$stash |
63 | } = (); |
64 | if (my @requires_fail |
65 | = grep !exists $has_methods{$_}, @{$info->{requires}||[]}) { |
66 | # role -> role, add to requires, role -> class, error out |
67 | if (my $to_info = $INFO{$to}) { |
68 | push @{$to_info->{requires}||=[]}, @requires_fail; |
69 | } else { |
70 | die "Can't apply ${role} to ${to} - missing ".join(', ', @requires_fail); |
71 | } |
72 | } |
73 | |
74 | my @to_install = grep !exists $has_methods{$_}, keys %$methods; |
75 | foreach my $i (@to_install) { |
76 | no warnings 'once'; |
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77 | *{_getglob "${to}::${i}"} = $methods->{$i}; |
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78 | } |
79 | |
80 | foreach my $modifier (@{$info->{modifiers}||[]}) { |
81 | Class::Method::Modifiers::install_modifier($to, @{$modifier}); |
82 | } |
83 | |
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84 | # only add does() method to classes and only if they don't have one |
85 | if (not $INFO{$to} and not $to->can('does')) { |
86 | ${_getglob "${to}::does"} = \&does_role; |
87 | } |
88 | |
89 | |
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90 | # copy our role list into the target's |
91 | @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = (); |
92 | } |
93 | |
94 | sub does_role { |
95 | my ($package, $role) = @_; |
96 | return exists $APPLIED_TO{$package}{$role}; |
97 | } |
98 | |
99 | 1; |