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1 | package Role::Tiny; |
2 | |
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3 | use strict; |
4 | use warnings FATAL => 'all'; |
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5 | |
6 | our %INFO; |
7 | our %APPLIED_TO; |
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8 | our %COMPOSED; |
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9 | |
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10 | sub _getglob { no strict 'refs'; \*{$_[0]} } |
11 | |
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12 | sub _load_module { |
13 | return 1 if $_[0]->can('can'); |
14 | (my $proto = $_[0]) =~ s/::/\//g; |
15 | require "${proto}.pm"; |
16 | return 1; |
17 | } |
18 | |
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19 | sub import { |
20 | my $target = caller; |
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21 | my $me = $_[0]; |
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22 | strictures->import; |
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23 | # get symbol table reference |
24 | my $stash = do { no strict 'refs'; \%{"${target}::"} }; |
25 | # install before/after/around subs |
26 | foreach my $type (qw(before after around)) { |
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27 | *{_getglob "${target}::${type}"} = sub { |
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28 | require Class::Method::Modifiers; |
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29 | push @{$INFO{$target}{modifiers}||=[]}, [ $type => @_ ]; |
30 | }; |
31 | } |
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32 | *{_getglob "${target}::requires"} = sub { |
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33 | push @{$INFO{$target}{requires}||=[]}, @_; |
34 | }; |
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35 | *{_getglob "${target}::with"} = sub { |
36 | die "Only one role supported at a time by with" if @_ > 1; |
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37 | $me->apply_role_to_package($_[0], $target); |
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38 | }; |
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39 | # grab all *non-constant* (ref eq 'SCALAR') subs present |
40 | # in the symbol table and store their refaddrs (no need to forcibly |
41 | # inflate constant subs into real subs) - also add '' to here (this |
42 | # is used later) |
43 | @{$INFO{$target}{not_methods}={}}{ |
44 | '', map { *$_{CODE}||() } grep !(ref eq 'SCALAR'), values %$stash |
45 | } = (); |
46 | # a role does itself |
47 | $APPLIED_TO{$target} = { $target => undef }; |
48 | } |
49 | |
50 | sub apply_role_to_package { |
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51 | my ($me, $role, $to) = @_; |
52 | |
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53 | _load_module($role); |
54 | |
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55 | die "This is apply_role_to_package" if ref($to); |
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56 | die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; |
57 | |
58 | $me->_check_requires($to, $role, @{$info->{requires}||[]}); |
59 | |
60 | $me->_install_methods($to, $role); |
61 | |
62 | $me->_install_modifiers($to, $info->{modifiers}); |
63 | |
64 | # only add does() method to classes and only if they don't have one |
65 | if (not $INFO{$to} and not $to->can('does')) { |
66 | *{_getglob "${to}::does"} = \&does_role; |
67 | } |
68 | |
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69 | # copy our role list into the target's |
70 | @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = (); |
71 | } |
72 | |
73 | sub apply_roles_to_object { |
74 | my ($me, $object, @roles) = @_; |
75 | die "No roles supplied!" unless @roles; |
76 | my $class = ref($object); |
77 | bless($object, $me->create_class_with_roles($class, @roles)); |
78 | $object; |
79 | } |
80 | |
81 | sub create_class_with_roles { |
82 | my ($me, $superclass, @roles) = @_; |
83 | |
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84 | die "No roles supplied!" unless @roles; |
85 | |
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86 | my $new_name = join('+', $superclass, my $compose_name = join '+', @roles); |
87 | return $new_name if $COMPOSED{class}{$new_name}; |
88 | |
89 | foreach my $role (@roles) { |
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90 | _load_module($role); |
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91 | die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; |
92 | } |
93 | |
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94 | if ($] > 5.010) { |
95 | require mro; |
96 | } else { |
97 | require MRO::Compat; |
98 | } |
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99 | |
100 | my @composable = map $me->_composable_package_for($_), reverse @roles; |
101 | |
102 | *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ]; |
103 | |
104 | my @info = map +($INFO{$_} ? $INFO{$_} : ()), @roles; |
105 | |
106 | $me->_check_requires( |
107 | $new_name, $compose_name, |
108 | do { my %h; @h{map @{$_->{requires}||[]}, @info} = (); keys %h } |
109 | ); |
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110 | |
111 | *{_getglob "${new_name}::does"} = \&does_role unless $new_name->can('does'); |
112 | |
113 | @{$APPLIED_TO{$new_name}||={}}{ |
114 | map keys %{$APPLIED_TO{$_}}, @roles |
115 | } = (); |
116 | |
117 | $COMPOSED{class}{$new_name} = 1; |
118 | return $new_name; |
119 | } |
120 | |
121 | sub _composable_package_for { |
122 | my ($me, $role) = @_; |
123 | my $composed_name = 'Role::Tiny::_COMPOSABLE::'.$role; |
124 | return $composed_name if $COMPOSED{role}{$composed_name}; |
125 | $me->_install_methods($composed_name, $role); |
126 | my $base_name = $composed_name.'::_BASE'; |
127 | *{_getglob("${composed_name}::ISA")} = [ $base_name ]; |
128 | my $modifiers = $INFO{$role}{modifiers}||[]; |
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129 | my @mod_base; |
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130 | foreach my $modified ( |
131 | do { my %h; @h{map $_->[1], @$modifiers} = (); keys %h } |
132 | ) { |
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133 | push @mod_base, "sub ${modified} { shift->next::method(\@_) }"; |
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134 | } |
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135 | eval(my $code = join "\n", "package ${base_name};", @mod_base); |
136 | die "Evaling failed: $@\nTrying to eval:\n${code}" if $@; |
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137 | $me->_install_modifiers($composed_name, $modifiers); |
138 | $COMPOSED{role}{$composed_name} = 1; |
139 | return $composed_name; |
140 | } |
141 | |
142 | sub _check_requires { |
143 | my ($me, $to, $name, @requires) = @_; |
144 | if (my @requires_fail = grep !$to->can($_), @requires) { |
145 | # role -> role, add to requires, role -> class, error out |
146 | if (my $to_info = $INFO{$to}) { |
147 | push @{$to_info->{requires}||=[]}, @requires_fail; |
148 | } else { |
149 | die "Can't apply ${name} to ${to} - missing ".join(', ', @requires_fail); |
150 | } |
151 | } |
152 | } |
153 | |
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154 | sub _concrete_methods_of { |
155 | my ($me, $role) = @_; |
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156 | my $info = $INFO{$role}; |
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157 | $info->{methods} ||= do { |
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158 | # grab role symbol table |
159 | my $stash = do { no strict 'refs'; \%{"${role}::"}}; |
160 | my $not_methods = $info->{not_methods}; |
161 | +{ |
162 | # grab all code entries that aren't in the not_methods list |
163 | map { |
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164 | my $code = *{$stash->{$_}}{CODE}; |
165 | # rely on the '' key we added in import for "no code here" |
166 | exists $not_methods->{$code||''} ? () : ($_ => $code) |
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167 | } grep !(ref($stash->{$_}) eq 'SCALAR'), keys %$stash |
168 | }; |
169 | }; |
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170 | } |
171 | |
172 | sub methods_provided_by { |
173 | my ($me, $role) = @_; |
174 | die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; |
175 | (keys %{$me->_concrete_methods_of($role)}, @{$info->{requires}||[]}); |
176 | } |
177 | |
178 | sub _install_methods { |
179 | my ($me, $to, $role) = @_; |
180 | |
181 | my $info = $INFO{$role}; |
182 | |
183 | my $methods = $me->_concrete_methods_of($role); |
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184 | |
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185 | # grab target symbol table |
186 | my $stash = do { no strict 'refs'; \%{"${to}::"}}; |
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187 | |
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188 | # determine already extant methods of target |
189 | my %has_methods; |
190 | @has_methods{grep |
191 | +((ref($stash->{$_}) eq 'SCALAR') || (*{$stash->{$_}}{CODE})), |
192 | keys %$stash |
193 | } = (); |
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194 | |
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195 | foreach my $i (grep !exists $has_methods{$_}, keys %$methods) { |
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196 | no warnings 'once'; |
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197 | *{_getglob "${to}::${i}"} = $methods->{$i}; |
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198 | } |
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199 | } |
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200 | |
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201 | sub _install_modifiers { |
202 | my ($me, $to, $modifiers) = @_; |
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203 | if (my $info = $INFO{$to}) { |
204 | push @{$info->{modifiers}}, @{$modifiers||[]}; |
205 | } else { |
206 | foreach my $modifier (@{$modifiers||[]}) { |
207 | $me->_install_single_modifier($to, @$modifier); |
208 | } |
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209 | } |
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210 | } |
211 | |
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212 | sub _install_single_modifier { |
213 | my ($me, @args) = @_; |
214 | Class::Method::Modifiers::install_modifier(@args); |
215 | } |
216 | |
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217 | sub does_role { |
218 | my ($package, $role) = @_; |
219 | return exists $APPLIED_TO{$package}{$role}; |
220 | } |
221 | |
222 | 1; |