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1 | package Devel::SelfStubber; |
2 | require SelfLoader; |
3 | @ISA = qw(SelfLoader); |
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4 | @EXPORT = 'AUTOLOAD'; |
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5 | $JUST_STUBS = 1; |
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6 | $VERSION = 1.03; |
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7 | sub Version {$VERSION} |
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8 | |
9 | # Use as |
10 | # perl -e 'use Devel::SelfStubber;Devel::SelfStubber->stub(MODULE_NAME,LIB)' |
11 | # (LIB defaults to '.') e.g. |
12 | # perl -e 'use Devel::SelfStubber;Devel::SelfStubber->stub('Math::BigInt')' |
13 | # would print out stubs needed if you added a __DATA__ before the subs. |
14 | # Setting $Devel::SelfStubber::JUST_STUBS to 0 will print out the whole |
15 | # module with the stubs entered just before the __DATA__ |
16 | |
17 | sub _add_to_cache { |
18 | my($self,$fullname,$pack,$lines, $prototype) = @_; |
19 | push(@DATA,@{$lines}); |
20 | if($fullname){push(@STUBS,"sub $fullname $prototype;\n")}; # stubs |
21 | '1;'; |
22 | } |
23 | |
24 | sub _package_defined { |
25 | my($self,$line) = @_; |
26 | push(@DATA,$line); |
27 | } |
28 | |
29 | sub stub { |
30 | my($self,$module,$lib) = @_; |
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31 | my($line,$end_data,$fh,$mod_file,$found_selfloader); |
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32 | $lib ||= '.'; |
33 | ($mod_file = $module) =~ s,::,/,g; |
34 | |
35 | $mod_file = "$lib/$mod_file.pm"; |
36 | $fh = "${module}::DATA"; |
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37 | my (@BEFORE_DATA, @AFTER_DATA, @AFTER_END); |
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38 | @DATA = @STUBS = (); |
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39 | |
40 | open($fh,$mod_file) || die "Unable to open $mod_file"; |
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41 | local $/ = "\n"; |
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42 | while(defined ($line = <$fh>) and $line !~ m/^__DATA__/) { |
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43 | push(@BEFORE_DATA,$line); |
44 | $line =~ /use\s+SelfLoader/ && $found_selfloader++; |
45 | } |
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46 | (defined ($line) && $line =~ m/^__DATA__/) |
47 | || die "$mod_file doesn't contain a __DATA__ token"; |
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48 | $found_selfloader || |
49 | print 'die "\'use SelfLoader;\' statement NOT FOUND!!\n"',"\n"; |
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50 | if ($JUST_STUBS) { |
51 | $self->_load_stubs($module); |
52 | } else { |
53 | $self->_load_stubs($module, \@AFTER_END); |
54 | } |
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55 | if ( fileno($fh) ) { |
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56 | $end_data = 1; |
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57 | while(defined($line = <$fh>)) { |
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58 | push(@AFTER_DATA,$line); |
59 | } |
60 | } |
61 | unless ($JUST_STUBS) { |
62 | print @BEFORE_DATA; |
63 | } |
64 | print @STUBS; |
65 | unless ($JUST_STUBS) { |
66 | print "1;\n__DATA__\n",@DATA; |
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67 | if($end_data) { print "__END__ DATA\n",@AFTER_DATA; } |
68 | if(@AFTER_END) { print "__END__\n",@AFTER_END; } |
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69 | } |
70 | } |
71 | |
72 | 1; |
73 | __END__ |
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74 | |
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75 | =head1 NAME |
76 | |
77 | Devel::SelfStubber - generate stubs for a SelfLoading module |
78 | |
79 | =head1 SYNOPSIS |
80 | |
81 | To generate just the stubs: |
82 | |
83 | use Devel::SelfStubber; |
84 | Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR'); |
85 | |
86 | or to generate the whole module with stubs inserted correctly |
87 | |
88 | use Devel::SelfStubber; |
89 | $Devel::SelfStubber::JUST_STUBS=0; |
90 | Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR'); |
91 | |
92 | MODULENAME is the Perl module name, e.g. Devel::SelfStubber, |
93 | NOT 'Devel/SelfStubber' or 'Devel/SelfStubber.pm'. |
94 | |
95 | MY_LIB_DIR defaults to '.' if not present. |
96 | |
97 | =head1 DESCRIPTION |
98 | |
99 | Devel::SelfStubber prints the stubs you need to put in the module |
100 | before the __DATA__ token (or you can get it to print the entire |
101 | module with stubs correctly placed). The stubs ensure that if |
102 | a method is called, it will get loaded. They are needed specifically |
103 | for inherited autoloaded methods. |
104 | |
105 | This is best explained using the following example: |
106 | |
107 | Assume four classes, A,B,C & D. |
108 | |
109 | A is the root class, B is a subclass of A, C is a subclass of B, |
110 | and D is another subclass of A. |
111 | |
112 | A |
113 | / \ |
114 | B D |
115 | / |
116 | C |
117 | |
118 | If D calls an autoloaded method 'foo' which is defined in class A, |
119 | then the method is loaded into class A, then executed. If C then |
120 | calls method 'foo', and that method was reimplemented in class |
121 | B, but set to be autoloaded, then the lookup mechanism never gets to |
122 | the AUTOLOAD mechanism in B because it first finds the method |
123 | already loaded in A, and so erroneously uses that. If the method |
124 | foo had been stubbed in B, then the lookup mechanism would have |
125 | found the stub, and correctly loaded and used the sub from B. |
126 | |
127 | So, for classes and subclasses to have inheritance correctly |
128 | work with autoloading, you need to ensure stubs are loaded. |
129 | |
130 | The SelfLoader can load stubs automatically at module initialization |
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131 | with the statement 'SelfLoader-E<gt>load_stubs()';, but you may wish to |
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132 | avoid having the stub loading overhead associated with your |
133 | initialization (though note that the SelfLoader::load_stubs method |
134 | will be called sooner or later - at latest when the first sub |
135 | is being autoloaded). In this case, you can put the sub stubs |
136 | before the __DATA__ token. This can be done manually, but this |
137 | module allows automatic generation of the stubs. |
138 | |
139 | By default it just prints the stubs, but you can set the |
140 | global $Devel::SelfStubber::JUST_STUBS to 0 and it will |
141 | print out the entire module with the stubs positioned correctly. |
142 | |
143 | At the very least, this is useful to see what the SelfLoader |
144 | thinks are stubs - in order to ensure future versions of the |
145 | SelfStubber remain in step with the SelfLoader, the |
146 | SelfStubber actually uses the SelfLoader to determine which |
147 | stubs are needed. |
148 | |
149 | =cut |