1 | package Devel::FindRef; |
1 | package Devel::FindRef; |
2 | |
2 | |
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3 | no warnings; # I hate warning nazis |
3 | use strict; |
4 | use strict; |
4 | |
5 | |
5 | use XSLoader; |
6 | use XSLoader; |
6 | use Scalar::Util; |
7 | use Scalar::Util; |
7 | |
8 | |
8 | BEGIN { |
9 | BEGIN { |
9 | our $VERSION = '1.2'; |
10 | our $VERSION = '1.4'; |
10 | XSLoader::load __PACKAGE__, $VERSION; |
11 | XSLoader::load __PACKAGE__, $VERSION; |
11 | } |
12 | } |
12 | |
13 | |
13 | =head1 NAME |
14 | =head1 NAME |
14 | |
15 | |
15 | Devel::FindRef - where is that reference to my scalar hiding? |
16 | Devel::FindRef - where is that reference to my variable hiding? |
16 | |
17 | |
17 | =head1 SYNOPSIS |
18 | =head1 SYNOPSIS |
18 | |
19 | |
19 | use Devel::FindRef; |
20 | use Devel::FindRef; |
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21 | |
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22 | print Devel::FindRef::track \$some_variable; |
20 | |
23 | |
21 | =head1 DESCRIPTION |
24 | =head1 DESCRIPTION |
22 | |
25 | |
23 | Tracking down reference problems (e.g. you expect some object to be |
26 | Tracking down reference problems (e.g. you expect some object to be |
24 | destroyed, but there are still references to it that keep it alive) can be |
27 | destroyed, but there are still references to it that keep it alive) can be |
… | |
… | |
29 | the variables containing them. |
32 | the variables containing them. |
30 | |
33 | |
31 | For example, for this fragment: |
34 | For example, for this fragment: |
32 | |
35 | |
33 | package Test; |
36 | package Test; |
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37 | |
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38 | use Devel::FindRef; |
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39 | use Scalar::Util; |
34 | |
40 | |
35 | our $var = "hi\n"; |
41 | our $var = "hi\n"; |
36 | my $x = \$var; |
42 | my $global_my = \$var; |
37 | our %hash = (ukukey => \$var); |
43 | our %global_hash = (ukukey => \$var); |
38 | our $hash2 = {ukukey2 => \$var}; |
44 | our $global_hashref = { ukukey2 => \$var }; |
39 | |
45 | |
40 | sub testsub { |
46 | sub testsub { |
41 | my $local = $hash2; |
47 | my $testsub_local = $global_hashref; |
42 | print Devel::FindRef::track \$var; |
48 | print Devel::FindRef::track \$var; |
43 | } |
49 | } |
44 | |
50 | |
45 | testsub; |
51 | |
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52 | my $closure = sub { |
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53 | my $closure_var = \$_[0]; |
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54 | Scalar::Util::weaken (my $weak_ref = \$var); |
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55 | testsub; |
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56 | }; |
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57 | |
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58 | $closure->($var); |
46 | |
59 | |
47 | The output is as follows (or similar to this, in case I forget to update |
60 | The output is as follows (or similar to this, in case I forget to update |
48 | the manpage after some changes): |
61 | the manpage after some changes): |
49 | |
62 | |
50 | SCALAR(0x7bd2d0) is |
63 | SCALAR(0x7cc888) [refcount 6] is |
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64 | +- referenced by REF(0x8abcc8) [refcount 1], which is |
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65 | | in the lexical '$closure_var' in CODE(0x8abc50) [refcount 4], which is |
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66 | | +- the closure created at tst:18. |
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67 | | +- referenced by REF(0x7d3c58) [refcount 1], which is |
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68 | | | in the lexical '$closure' in CODE(0x7ae530) [refcount 2], which is |
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69 | | | +- the containing scope for CODE(0x8ab430) [refcount 3], which is |
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70 | | | | in the global &Test::testsub. |
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71 | | | +- the main body of the program. |
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72 | | +- in the lexical '&' in CODE(0x7ae530) [refcount 2], which was seen before. |
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73 | +- referenced by REF(0x7cc7c8) [refcount 1], which is |
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74 | | in the lexical '$global_my' in CODE(0x7ae530) [refcount 2], which was seen before. |
51 | in the global $Test::var. |
75 | +- in the global $Test::var. |
52 | referenced by REF(0x7bd240), which is |
76 | +- referenced by REF(0x7cc558) [refcount 1], which is |
53 | in the member 'ukukey2' of HASH(0x7bd228), which is |
77 | | in the member 'ukukey2' of HASH(0x7ae140) [refcount 2], which is |
54 | referenced by REF(0x81dae8), which is |
78 | | +- referenced by REF(0x8abad0) [refcount 1], which is |
55 | in the lexical '$local' in CODE(0x81da88), which is |
79 | | | in the lexical '$testsub_local' in CODE(0x8ab430) [refcount 3], which was seen before. |
56 | in the global &Test::testsub. |
80 | | +- referenced by REF(0x8ab4f0) [refcount 1], which is |
57 | referenced by REF(0x81da40), which is |
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58 | in the global $Test::hash2. |
81 | | in the global $Test::global_hashref. |
59 | referenced by REF(0x79f3f8), which is |
82 | +- referenced by REF(0x7ae518) [refcount 1], which is |
60 | in the lexical '$x' in CODE(0x79f518), which is |
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61 | the containing scope for CODE(0x81da88), which is |
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62 | in the global &Test::testsub. |
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63 | referenced by REF(0x79f2f0), which is |
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64 | not found anywhere I looked :( |
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65 | referenced by REF(0x79f140), which is |
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66 | in the member 'ukukey' of HASH(0x81d698), which is |
83 | | in the member 'ukukey' of HASH(0x7d3bb0) [refcount 1], which is |
67 | in the global %Test::hash. |
84 | | in the global %Test::global_hash. |
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85 | +- referenced by REF(0x7ae2f0) [refcount 1], which is |
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86 | a temporary on the stack. |
68 | |
87 | |
69 | It is a bit convoluted to read, but basically it says that the value |
88 | It is a bit convoluted to read, but basically it says that the value |
70 | stored in C<$var> can be found: |
89 | stored in C<$var> is referenced by: |
71 | |
90 | |
72 | =over 4 |
91 | =over 4 |
73 | |
92 | |
74 | =item - in some variable C<$x> whose origin is not known (I frankly have no |
93 | =item - in the lexical C<$closure_var> (0x8abcc8), which is inside an instantiated |
75 | idea why, hints accepted). |
94 | closure, which in turn is used quite a bit. |
76 | |
95 | |
77 | =item - in the hash element with key C<ukukey> in the hash stored in C<%Test::hash>. |
96 | =item - in the package-level lexical C<$global_my>. |
78 | |
97 | |
79 | =item - in the global variable named C<$Test::var>. |
98 | =item - in the global package variable named C<$Test::var>. |
80 | |
99 | |
81 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
100 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
82 | C<$local> in the sub C<Test::testsub> and also in the hash referenced by |
101 | C<$testsub_local> in the sub C<Test::testsub> and also in the hash |
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102 | C<$referenced by Test::hash2>. |
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103 | |
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104 | =item - in the hash element with key C<ukukey> in the hash stored in |
83 | C<$Test::hash2>. |
105 | C<%Test::hash>. |
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106 | |
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107 | =item - some anonymous mortalised reference on the stack (which is caused |
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108 | by calling C<track> with the expression C<\$var>, which creates the |
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109 | reference). |
84 | |
110 | |
85 | =back |
111 | =back |
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112 | |
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113 | And all these account for six reference counts. |
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114 | |
86 | |
115 | |
87 | =head1 EXPORTS |
116 | =head1 EXPORTS |
88 | |
117 | |
89 | None. |
118 | None. |
90 | |
119 | |
… | |
… | |
102 | |
131 | |
103 | =cut |
132 | =cut |
104 | |
133 | |
105 | sub find($); |
134 | sub find($); |
106 | |
135 | |
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136 | sub _f($) { |
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137 | "$_[0] [refcount " . (_refcnt $_[0]) . "]" |
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138 | } |
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139 | |
107 | sub track { |
140 | sub track { |
108 | my ($ref, $depth) = @_; |
141 | my ($ref, $depth) = @_; |
109 | @_ = (); |
142 | @_ = (); |
110 | |
143 | |
111 | my $buf = ""; |
144 | my $buf = ""; |
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145 | my %seen; |
112 | |
146 | |
113 | Scalar::Util::weaken $ref; |
147 | Scalar::Util::weaken $ref; |
114 | |
148 | |
115 | my $track; $track = sub { |
149 | my $track; $track = sub { |
116 | my ($refref, $depth, $indent) = @_; |
150 | my ($refref, $depth, $indent) = @_; |
117 | |
151 | |
118 | if ($depth) { |
152 | if ($depth) { |
119 | my (@about) = find $$refref; |
153 | my (@about) = find $$refref; |
120 | if (@about) { |
154 | if (@about) { |
121 | for my $about (@about) { |
155 | for my $about (@about) { |
122 | $buf .= (" ") x $indent; |
156 | $buf .= "$indent" . (@about > 1 ? "+- " : "") . $about->[0]; |
123 | $buf .= $about->[0]; |
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124 | if (@$about > 1) { |
157 | if (@$about > 1) { |
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158 | if ($seen{ref2ptr $about->[1]}++) { |
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159 | $buf .= " " . (_f $about->[1]) . ", which was seen before.\n"; |
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160 | } else { |
125 | $buf .= " $about->[1], which is\n"; |
161 | $buf .= " " . (_f $about->[1]) . ", which is\n"; |
126 | $track->(\$about->[1], $depth - 1, $indent + 1); |
162 | $track->(\$about->[1], $depth - 1, $about == $about[-1] ? "$indent " : "$indent| "); |
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163 | } |
127 | } else { |
164 | } else { |
128 | $buf .= ".\n"; |
165 | $buf .= ".\n"; |
129 | } |
166 | } |
130 | } |
167 | } |
131 | } else { |
168 | } else { |
132 | $buf .= (" ") x $indent; |
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133 | $buf .= "not found anywhere I looked :(\n"; |
169 | $buf .= "$indent not found anywhere I looked :(\n"; |
134 | } |
170 | } |
135 | } else { |
171 | } else { |
136 | $buf .= (" ") x $indent; |
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137 | $buf .= "not referenced within the search depth.\n"; |
172 | $buf .= "$indent not referenced within the search depth.\n"; |
138 | } |
173 | } |
139 | }; |
174 | }; |
140 | |
175 | |
141 | $buf .= "$ref is\n"; |
176 | $buf .= (_f $ref) . " is\n"; |
142 | $track->(\$ref, $depth || 10, 1); |
177 | $track->(\$ref, $depth || $ENV{PERL_DEVEL_FINDREF_DEPTH} || 10, ""); |
143 | $buf |
178 | $buf |
144 | } |
179 | } |
145 | |
180 | |
146 | =item @references = Devel::FindRef::find $ref |
181 | =item @references = Devel::FindRef::find $ref |
147 | |
182 | |
… | |
… | |
156 | =cut |
191 | =cut |
157 | |
192 | |
158 | sub find($) { |
193 | sub find($) { |
159 | my ($about, $excl) = &find_; |
194 | my ($about, $excl) = &find_; |
160 | my %excl = map +($_ => undef), @$excl; |
195 | my %excl = map +($_ => undef), @$excl; |
161 | grep !exists $excl{$_->[1] + 0}, @$about |
196 | grep !exists $excl{ref2ptr $_->[1]}, @$about |
162 | } |
197 | } |
163 | |
198 | |
164 | =item $ref = Devel::FindRef::ptr2ref $integer |
199 | =item $ref = Devel::FindRef::ptr2ref $integer |
165 | |
200 | |
166 | Sometimes you know (from debugging output) the address of a perl scalar |
201 | Sometimes you know (from debugging output) the address of a perl scalar |
… | |
… | |
169 | call on valid addresses, but extremely dangerous to call on invalid ones. |
204 | call on valid addresses, but extremely dangerous to call on invalid ones. |
170 | |
205 | |
171 | # we know that HASH(0x176ff70) exists, so turn it into a hashref: |
206 | # we know that HASH(0x176ff70) exists, so turn it into a hashref: |
172 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
207 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
173 | |
208 | |
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209 | =item $ref = Devel::FindRef::ref2ptr $reference |
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210 | |
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211 | The opposite of C<ptr2ref>, above: returns the internal address of the |
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212 | value pointed to by the passed reference. I<No checks whatsoever will be |
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213 | done>, so don't use this. |
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214 | |
174 | =back |
215 | =back |
175 | |
216 | |
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217 | =head1 ENVIRONMENT VARIABLES |
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218 | |
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219 | You can set the environment variable C<PERL_DEVEL_FINDREF_DEPTH> to an |
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220 | integer to override the default depth in C<track>. If a call explicitly |
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221 | specified a depth it is not overridden. |
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222 | |
176 | =head1 AUTHOR |
223 | =head1 AUTHOR |
177 | |
224 | |
178 | Marc Lehmann <pcg@goof.com>. |
225 | Marc Lehmann <pcg@goof.com>. |
179 | |
226 | |
180 | =head1 BUGS |
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181 | |
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182 | Only code values, arrays, hashes, scalars and magic are being looked at. |
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183 | |
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184 | This is a quick hack only. |
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185 | |
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186 | =head1 COPYRIGHT AND LICENSE |
227 | =head1 COPYRIGHT AND LICENSE |
187 | |
228 | |
188 | Copyright (C) 2007 by Marc Lehmann. |
229 | Copyright (C) 2007, 2008 by Marc Lehmann. |
189 | |
230 | |
190 | This library is free software; you can redistribute it and/or modify |
231 | This library is free software; you can redistribute it and/or modify |
191 | it under the same terms as Perl itself, either Perl version 5.8.8 or, |
232 | it under the same terms as Perl itself, either Perl version 5.8.8 or, |
192 | at your option, any later version of Perl 5 you may have available. |
233 | at your option, any later version of Perl 5 you may have available. |
193 | |
234 | |