| 1 | package Devel::FindRef; |
1 | package Devel::FindRef; |
| 2 | |
2 | |
|
|
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 = '1.3'; |
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 variable 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 | |
|
|
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; |
|
|
37 | |
|
|
38 | use Devel::FindRef; |
|
|
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 | |
|
|
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(0x814ece8) 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 $Test::var. |
| 52 | +- referenced by REF(0x814f9e4), which is |
76 | +- referenced by REF(0x7cc558) [refcount 1], which is |
| 53 | | in the lexical '$x' in CODE(0x814ed78), which is |
|
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| 54 | | the containing scope for CODE(0x820c4b0), which is |
|
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| 55 | | in the global &Test::testsub. |
|
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| 56 | +- referenced by REF(0x814ed6c), which is |
|
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| 57 | | in the member 'ukukey' of HASH(0x81da20c), which is |
77 | | in the member 'ukukey2' of HASH(0x7ae140) [refcount 2], which is |
|
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78 | | +- referenced by REF(0x8abad0) [refcount 1], which is |
|
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79 | | | in the lexical '$testsub_local' in CODE(0x8ab430) [refcount 3], which was seen before. |
|
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80 | | +- referenced by REF(0x8ab4f0) [refcount 1], which is |
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81 | | in the global $Test::global_hashref. |
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82 | +- referenced by REF(0x7ae518) [refcount 1], which is |
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83 | | in the member 'ukukey' of HASH(0x7d3bb0) [refcount 1], which is |
| 58 | | in the global %Test::hash. |
84 | | in the global %Test::global_hash. |
| 59 | +- referenced by REF(0x814ec28), which is |
85 | +- referenced by REF(0x7ae2f0) [refcount 1], which is |
| 60 | | not found anywhere I looked :( |
86 | a temporary on the stack. |
| 61 | +- referenced by REF(0x814eb44), which is |
|
|
| 62 | in the member 'ukukey2' of HASH(0x814f99c), which is |
|
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| 63 | +- referenced by REF(0x820c450), which is |
|
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| 64 | | in the lexical '$local' in CODE(0x820c4b0), which was seen before. |
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| 65 | +- referenced by REF(0x820c204), which is |
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| 66 | in the global $Test::hash2. |
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| 67 | |
87 | |
| 68 | It is a bit convoluted to read, but basically it says that the value |
88 | It is a bit convoluted to read, but basically it says that the value |
| 69 | stored in C<$var> can be found: |
89 | stored in C<$var> is referenced by: |
| 70 | |
90 | |
| 71 | =over 4 |
91 | =over 4 |
| 72 | |
92 | |
| 73 | =item - in some variable C<$x> whose origin is not known (I frankly have no |
93 | =item - the lexical C<$closure_var> (0x8abcc8), which is inside an instantiated |
| 74 | idea why, hints accepted). |
94 | closure, which in turn is used quite a bit. |
| 75 | |
95 | |
| 76 | =item - in the hash element with key C<ukukey> in the hash stored in C<%Test::hash>. |
96 | =item - the package-level lexical C<$global_my>. |
| 77 | |
97 | |
| 78 | =item - in the global variable named C<$Test::var>. |
98 | =item - the global package variable named C<$Test::var>. |
| 79 | |
99 | |
| 80 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
100 | =item - the hash element C<ukukey2>, in the hash in the my variable |
| 81 | 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<$referenced by Test::hash2>. |
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103 | |
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104 | =item - the hash element with key C<ukukey> in the hash stored in |
| 82 | C<$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). |
| 83 | |
110 | |
| 84 | =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 | |
| 85 | |
115 | |
| 86 | =head1 EXPORTS |
116 | =head1 EXPORTS |
| 87 | |
117 | |
| 88 | None. |
118 | None. |
| 89 | |
119 | |
| … | |
… | |
| 100 | This is the function you most often use. |
130 | This is the function you most often use. |
| 101 | |
131 | |
| 102 | =cut |
132 | =cut |
| 103 | |
133 | |
| 104 | sub find($); |
134 | sub find($); |
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135 | |
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136 | sub _f($) { |
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137 | "$_[0] [refcount " . (_refcnt $_[0]) . "]" |
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138 | } |
| 105 | |
139 | |
| 106 | sub track { |
140 | sub track { |
| 107 | my ($ref, $depth) = @_; |
141 | my ($ref, $depth) = @_; |
| 108 | @_ = (); |
142 | @_ = (); |
| 109 | |
143 | |
| … | |
… | |
| 117 | |
151 | |
| 118 | if ($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 | $buf .= "$indent" . (@about > 1 ? "+- " : " ") . $about->[0]; |
156 | $buf .= "$indent" . (@about > 1 ? "+- " : "") . $about->[0]; |
| 123 | if (@$about > 1) { |
157 | if (@$about > 1) { |
| 124 | if ($seen{$about->[1]+0}++) { |
158 | if ($seen{ref2ptr $about->[1]}++) { |
| 125 | $buf .= " $about->[1], which was seen before.\n"; |
159 | $buf .= " " . (_f $about->[1]) . ", which was seen before.\n"; |
| 126 | } else { |
160 | } else { |
| 127 | $buf .= " $about->[1], which is\n"; |
161 | $buf .= " " . (_f $about->[1]) . ", which is\n"; |
| 128 | $track->(\$about->[1], $depth - 1, $about == $about[-1] ? "$indent " : "$indent| "); |
162 | $track->(\$about->[1], $depth - 1, $about == $about[-1] ? "$indent " : "$indent| "); |
| 129 | } |
163 | } |
| 130 | } else { |
164 | } else { |
| 131 | $buf .= ".\n"; |
165 | $buf .= ".\n"; |
| 132 | } |
166 | } |
| … | |
… | |
| 137 | } else { |
171 | } else { |
| 138 | $buf .= "$indent not referenced within the search depth.\n"; |
172 | $buf .= "$indent not referenced within the search depth.\n"; |
| 139 | } |
173 | } |
| 140 | }; |
174 | }; |
| 141 | |
175 | |
| 142 | $buf .= "$ref is\n"; |
176 | $buf .= (_f $ref) . " is\n"; |
| 143 | $track->(\$ref, $depth || $ENV{PERL_DEVEL_FINDREF_DEPTH} || 10, ""); |
177 | $track->(\$ref, $depth || $ENV{PERL_DEVEL_FINDREF_DEPTH} || 10, ""); |
| 144 | $buf |
178 | $buf |
| 145 | } |
179 | } |
| 146 | |
180 | |
| 147 | =item @references = Devel::FindRef::find $ref |
181 | =item @references = Devel::FindRef::find $ref |
| … | |
… | |
| 157 | =cut |
191 | =cut |
| 158 | |
192 | |
| 159 | sub find($) { |
193 | sub find($) { |
| 160 | my ($about, $excl) = &find_; |
194 | my ($about, $excl) = &find_; |
| 161 | my %excl = map +($_ => undef), @$excl; |
195 | my %excl = map +($_ => undef), @$excl; |
| 162 | grep !exists $excl{$_->[1] + 0}, @$about |
196 | grep !exists $excl{ref2ptr $_->[1]}, @$about |
| 163 | } |
197 | } |
| 164 | |
198 | |
| 165 | =item $ref = Devel::FindRef::ptr2ref $integer |
199 | =item $ref = Devel::FindRef::ptr2ref $integer |
| 166 | |
200 | |
| 167 | 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 |
| … | |
… | |
| 170 | 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. |
| 171 | |
205 | |
| 172 | # 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: |
| 173 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
207 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
| 174 | |
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 | |
| 175 | =back |
215 | =back |
| 176 | |
216 | |
| 177 | =head1 ENVIRONMENT VARIABLES |
217 | =head1 ENVIRONMENT VARIABLES |
| 178 | |
218 | |
| 179 | You can set the environment variable C<PERL_DEVEL_FINDREF_DEPTH> to an |
219 | You can set the environment variable C<PERL_DEVEL_FINDREF_DEPTH> to an |
| … | |
… | |
| 182 | |
222 | |
| 183 | =head1 AUTHOR |
223 | =head1 AUTHOR |
| 184 | |
224 | |
| 185 | Marc Lehmann <pcg@goof.com>. |
225 | Marc Lehmann <pcg@goof.com>. |
| 186 | |
226 | |
| 187 | =head1 BUGS |
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| 188 | |
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| 189 | Only code values, arrays, hashes, scalars and magic are being looked at. |
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| 190 | |
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| 191 | This is a quick hack only. |
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| 192 | |
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| 193 | =head1 COPYRIGHT AND LICENSE |
227 | =head1 COPYRIGHT AND LICENSE |
| 194 | |
228 | |
| 195 | Copyright (C) 2007 by Marc Lehmann. |
229 | Copyright (C) 2007, 2008 by Marc Lehmann. |
| 196 | |
230 | |
| 197 | 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 |
| 198 | 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, |
| 199 | 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. |
| 200 | |
234 | |
