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f8881bd9 AD |
1 | package Devel::SelfStubber; |
2 | require SelfLoader; | |
3 | @ISA = qw(SelfLoader); | |
73c78b0a | 4 | @EXPORT = 'AUTOLOAD'; |
f8881bd9 | 5 | $JUST_STUBS = 1; |
7f4f6daf | 6 | $VERSION = 1.03; |
a1457ef1 | 7 | sub Version {$VERSION} |
f8881bd9 AD |
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,$lib) = @_; | |
33235a50 | 31 | my($line,$end_data,$fh,$mod_file,$found_selfloader); |
f8881bd9 AD |
32 | $lib ||= '.'; |
33 | ($mod_file = $module) =~ s,::,/,g; | |
34 | ||
35 | $mod_file = "$lib/$mod_file.pm"; | |
36 | $fh = "${module}::DATA"; | |
33235a50 | 37 | my (@BEFORE_DATA, @AFTER_DATA, @AFTER_END); |
7f4f6daf | 38 | @DATA = @STUBS = (); |
f8881bd9 AD |
39 | |
40 | open($fh,$mod_file) || die "Unable to open $mod_file"; | |
7f4f6daf | 41 | local $/ = "\n"; |
40da2db3 | 42 | while(defined ($line = <$fh>) and $line !~ m/^__DATA__/) { |
f8881bd9 AD |
43 | push(@BEFORE_DATA,$line); |
44 | $line =~ /use\s+SelfLoader/ && $found_selfloader++; | |
45 | } | |
7f4f6daf NC |
46 | (defined ($line) && $line =~ m/^__DATA__/) |
47 | || die "$mod_file doesn't contain a __DATA__ token"; | |
f8881bd9 AD |
48 | $found_selfloader || |
49 | print 'die "\'use SelfLoader;\' statement NOT FOUND!!\n"',"\n"; | |
33235a50 NC |
50 | if ($JUST_STUBS) { |
51 | $self->_load_stubs($module); | |
52 | } else { | |
53 | $self->_load_stubs($module, \@AFTER_END); | |
54 | } | |
f8881bd9 | 55 | if ( fileno($fh) ) { |
33235a50 | 56 | $end_data = 1; |
40da2db3 | 57 | while(defined($line = <$fh>)) { |
f8881bd9 AD |
58 | push(@AFTER_DATA,$line); |
59 | } | |
60 | } | |
1a36cb9f | 61 | close($fh); |
f8881bd9 AD |
62 | unless ($JUST_STUBS) { |
63 | print @BEFORE_DATA; | |
64 | } | |
65 | print @STUBS; | |
66 | unless ($JUST_STUBS) { | |
67 | print "1;\n__DATA__\n",@DATA; | |
33235a50 NC |
68 | if($end_data) { print "__END__ DATA\n",@AFTER_DATA; } |
69 | if(@AFTER_END) { print "__END__\n",@AFTER_END; } | |
f8881bd9 AD |
70 | } |
71 | } | |
72 | ||
73 | 1; | |
74 | __END__ | |
cb1a09d0 | 75 | |
f8881bd9 AD |
76 | =head1 NAME |
77 | ||
78 | Devel::SelfStubber - generate stubs for a SelfLoading module | |
79 | ||
80 | =head1 SYNOPSIS | |
81 | ||
82 | To generate just the stubs: | |
83 | ||
84 | use Devel::SelfStubber; | |
85 | Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR'); | |
86 | ||
87 | or to generate the whole module with stubs inserted correctly | |
88 | ||
89 | use Devel::SelfStubber; | |
90 | $Devel::SelfStubber::JUST_STUBS=0; | |
91 | Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR'); | |
92 | ||
93 | MODULENAME is the Perl module name, e.g. Devel::SelfStubber, | |
94 | NOT 'Devel/SelfStubber' or 'Devel/SelfStubber.pm'. | |
95 | ||
96 | MY_LIB_DIR defaults to '.' if not present. | |
97 | ||
98 | =head1 DESCRIPTION | |
99 | ||
100 | Devel::SelfStubber prints the stubs you need to put in the module | |
101 | before the __DATA__ token (or you can get it to print the entire | |
102 | module with stubs correctly placed). The stubs ensure that if | |
103 | a method is called, it will get loaded. They are needed specifically | |
104 | for inherited autoloaded methods. | |
105 | ||
106 | This is best explained using the following example: | |
107 | ||
108 | Assume four classes, A,B,C & D. | |
109 | ||
110 | A is the root class, B is a subclass of A, C is a subclass of B, | |
111 | and D is another subclass of A. | |
112 | ||
113 | A | |
114 | / \ | |
115 | B D | |
116 | / | |
117 | C | |
118 | ||
119 | If D calls an autoloaded method 'foo' which is defined in class A, | |
120 | then the method is loaded into class A, then executed. If C then | |
121 | calls method 'foo', and that method was reimplemented in class | |
122 | B, but set to be autoloaded, then the lookup mechanism never gets to | |
123 | the AUTOLOAD mechanism in B because it first finds the method | |
124 | already loaded in A, and so erroneously uses that. If the method | |
125 | foo had been stubbed in B, then the lookup mechanism would have | |
126 | found the stub, and correctly loaded and used the sub from B. | |
127 | ||
128 | So, for classes and subclasses to have inheritance correctly | |
129 | work with autoloading, you need to ensure stubs are loaded. | |
130 | ||
131 | The SelfLoader can load stubs automatically at module initialization | |
1fef88e7 | 132 | with the statement 'SelfLoader-E<gt>load_stubs()';, but you may wish to |
f8881bd9 AD |
133 | avoid having the stub loading overhead associated with your |
134 | initialization (though note that the SelfLoader::load_stubs method | |
135 | will be called sooner or later - at latest when the first sub | |
136 | is being autoloaded). In this case, you can put the sub stubs | |
137 | before the __DATA__ token. This can be done manually, but this | |
138 | module allows automatic generation of the stubs. | |
139 | ||
140 | By default it just prints the stubs, but you can set the | |
141 | global $Devel::SelfStubber::JUST_STUBS to 0 and it will | |
142 | print out the entire module with the stubs positioned correctly. | |
143 | ||
144 | At the very least, this is useful to see what the SelfLoader | |
145 | thinks are stubs - in order to ensure future versions of the | |
146 | SelfStubber remain in step with the SelfLoader, the | |
147 | SelfStubber actually uses the SelfLoader to determine which | |
148 | stubs are needed. | |
149 | ||
150 | =cut |