| 1 | package Devel::FindRef; |
1 | package Devel::FindRef; |
| 2 | |
2 | |
| 3 | use strict; |
3 | use common::sense; |
| 4 | |
4 | |
| 5 | use XSLoader; |
5 | use XSLoader; |
| 6 | use Scalar::Util; |
6 | use Scalar::Util; |
| 7 | |
7 | |
| 8 | BEGIN { |
8 | BEGIN { |
| 9 | our $VERSION = '1.2'; |
9 | our $VERSION = 1.44; |
| 10 | XSLoader::load __PACKAGE__, $VERSION; |
10 | XSLoader::load __PACKAGE__, $VERSION; |
| 11 | } |
11 | } |
| 12 | |
12 | |
| 13 | =head1 NAME |
13 | =head1 NAME |
| 14 | |
14 | |
| 15 | Devel::FindRef - where is that reference to my scalar hiding? |
15 | Devel::FindRef - where is that reference to my variable hiding? |
| 16 | |
16 | |
| 17 | =head1 SYNOPSIS |
17 | =head1 SYNOPSIS |
| 18 | |
18 | |
| 19 | use Devel::FindRef; |
19 | use Devel::FindRef; |
|
|
20 | |
|
|
21 | print Devel::FindRef::track \$some_variable; |
| 20 | |
22 | |
| 21 | =head1 DESCRIPTION |
23 | =head1 DESCRIPTION |
| 22 | |
24 | |
| 23 | Tracking down reference problems (e.g. you expect some object to be |
25 | 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 |
26 | destroyed, but there are still references to it that keep it alive) can be |
| … | |
… | |
| 28 | The C<track> function can help track down some of those references back to |
30 | The C<track> function can help track down some of those references back to |
| 29 | the variables containing them. |
31 | the variables containing them. |
| 30 | |
32 | |
| 31 | For example, for this fragment: |
33 | For example, for this fragment: |
| 32 | |
34 | |
| 33 | package Test; |
35 | package Test; |
|
|
36 | |
|
|
37 | use Devel::FindRef; |
|
|
38 | use Scalar::Util; |
| 34 | |
39 | |
| 35 | our $var = "hi\n"; |
40 | our $var = "hi\n"; |
| 36 | my $x = \$var; |
41 | my $global_my = \$var; |
| 37 | our %hash = (ukukey => \$var); |
42 | our %global_hash = (ukukey => \$var); |
| 38 | our $hash2 = {ukukey2 => \$var}; |
43 | our $global_hashref = { ukukey2 => \$var }; |
| 39 | |
44 | |
| 40 | sub testsub { |
45 | sub testsub { |
| 41 | my $local = $hash2; |
46 | my $testsub_local = $global_hashref; |
| 42 | print Devel::FindRef::track \$var; |
47 | print Devel::FindRef::track \$var; |
| 43 | } |
48 | } |
| 44 | |
49 | |
| 45 | testsub; |
50 | my $closure = sub { |
|
|
51 | my $closure_var = \$_[0]; |
|
|
52 | Scalar::Util::weaken (my $weak_ref = \$var); |
|
|
53 | testsub; |
|
|
54 | }; |
|
|
55 | |
|
|
56 | $closure->($var); |
| 46 | |
57 | |
| 47 | The output is as follows (or similar to this, in case I forget to update |
58 | The output is as follows (or similar to this, in case I forget to update |
| 48 | the manpage after some changes): |
59 | the manpage after some changes): |
| 49 | |
60 | |
| 50 | SCALAR(0x7bd2d0) is |
61 | SCALAR(0x7cc888) [refcount 6] is |
|
|
62 | +- referenced by REF(0x8abcc8) [refcount 1], which is |
|
|
63 | | the lexical '$closure_var' in CODE(0x8abc50) [refcount 4], which is |
|
|
64 | | +- the closure created at tst:18. |
|
|
65 | | +- referenced by REF(0x7d3c58) [refcount 1], which is |
|
|
66 | | | the lexical '$closure' in CODE(0x7ae530) [refcount 2], which is |
|
|
67 | | | +- the containing scope for CODE(0x8ab430) [refcount 3], which is |
|
|
68 | | | | the global &Test::testsub. |
|
|
69 | | | +- the main body of the program. |
|
|
70 | | +- the lexical '&' in CODE(0x7ae530) [refcount 2], which was seen before. |
|
|
71 | +- referenced by REF(0x7cc7c8) [refcount 1], which is |
|
|
72 | | the lexical '$global_my' in CODE(0x7ae530) [refcount 2], which was seen before. |
| 51 | in the global $Test::var. |
73 | +- the global $Test::var. |
| 52 | referenced by REF(0x7bd240), which is |
74 | +- referenced by REF(0x7cc558) [refcount 1], which is |
| 53 | in the member 'ukukey2' of HASH(0x7bd228), which is |
75 | | the member 'ukukey2' of HASH(0x7ae140) [refcount 2], which is |
| 54 | referenced by REF(0x81dae8), which is |
76 | | +- referenced by REF(0x8abad0) [refcount 1], which is |
| 55 | in the lexical '$local' in CODE(0x81da88), which is |
77 | | | the lexical '$testsub_local' in CODE(0x8ab430) [refcount 3], which was seen before. |
| 56 | in the global &Test::testsub. |
78 | | +- referenced by REF(0x8ab4f0) [refcount 1], which is |
| 57 | referenced by REF(0x81da40), which is |
79 | | the global $Test::global_hashref. |
| 58 | in the global $Test::hash2. |
80 | +- referenced by REF(0x7ae518) [refcount 1], which is |
| 59 | referenced by REF(0x79f3f8), which is |
81 | | the member 'ukukey' of HASH(0x7d3bb0) [refcount 1], which is |
| 60 | in the lexical '$x' in CODE(0x79f518), which is |
82 | | the global %Test::global_hash. |
| 61 | the containing scope for CODE(0x81da88), which is |
|
|
| 62 | in the global &Test::testsub. |
|
|
| 63 | referenced by REF(0x79f2f0), which is |
83 | +- referenced by REF(0x7ae2f0) [refcount 1], which is |
| 64 | not found anywhere I looked :( |
84 | a temporary on the stack. |
| 65 | referenced by REF(0x79f140), which is |
|
|
| 66 | in the member 'ukukey' of HASH(0x81d698), which is |
|
|
| 67 | in the global %Test::hash. |
|
|
| 68 | |
85 | |
| 69 | It is a bit convoluted to read, but basically it says that the value |
86 | It is a bit convoluted to read, but basically it says that the value |
| 70 | stored in C<$var> can be found: |
87 | stored in C<$var> is referenced by: |
| 71 | |
88 | |
| 72 | =over 4 |
89 | =over 4 |
| 73 | |
90 | |
| 74 | =item - in some variable C<$x> whose origin is not known (I frankly have no |
91 | =item - the lexical C<$closure_var> (0x8abcc8), which is inside an instantiated |
| 75 | idea why, hints accepted). |
92 | closure, which in turn is used quite a bit. |
| 76 | |
93 | |
| 77 | =item - in the hash element with key C<ukukey> in the hash stored in C<%Test::hash>. |
94 | =item - the package-level lexical C<$global_my>. |
| 78 | |
95 | |
| 79 | =item - in the global variable named C<$Test::var>. |
96 | =item - the global package variable named C<$Test::var>. |
| 80 | |
97 | |
| 81 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
98 | =item - the hash element C<ukukey2>, in the hash in the my variable |
| 82 | C<$local> in the sub C<Test::testsub> and also in the hash referenced by |
99 | C<$testsub_local> in the sub C<Test::testsub> and also in the hash |
|
|
100 | C<$referenced by Test::hash2>. |
|
|
101 | |
|
|
102 | =item - the hash element with key C<ukukey> in the hash stored in |
| 83 | C<$Test::hash2>. |
103 | C<%Test::hash>. |
|
|
104 | |
|
|
105 | =item - some anonymous mortalised reference on the stack (which is caused |
|
|
106 | by calling C<track> with the expression C<\$var>, which creates the |
|
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107 | reference). |
| 84 | |
108 | |
| 85 | =back |
109 | =back |
|
|
110 | |
|
|
111 | And all these account for six reference counts. |
| 86 | |
112 | |
| 87 | =head1 EXPORTS |
113 | =head1 EXPORTS |
| 88 | |
114 | |
| 89 | None. |
115 | None. |
| 90 | |
116 | |
| … | |
… | |
| 96 | |
122 | |
| 97 | Track the perl value pointed to by C<$ref> up to a depth of C<$depth> and |
123 | Track the perl value pointed to by C<$ref> up to a depth of C<$depth> and |
| 98 | return a descriptive string. C<$ref> can point at any perl value, be it |
124 | return a descriptive string. C<$ref> can point at any perl value, be it |
| 99 | anonymous sub, hash, array, scalar etc. |
125 | anonymous sub, hash, array, scalar etc. |
| 100 | |
126 | |
| 101 | This is the function you most often use. |
127 | This is the function you most likely want to use when tracking down |
|
|
128 | references. |
| 102 | |
129 | |
| 103 | =cut |
130 | =cut |
| 104 | |
131 | |
| 105 | sub find($); |
132 | sub find($); |
|
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133 | |
|
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134 | sub _f($) { |
|
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135 | "$_[0] [refcount " . (_refcnt $_[0]) . "]" |
|
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136 | } |
| 106 | |
137 | |
| 107 | sub track { |
138 | sub track { |
| 108 | my ($ref, $depth) = @_; |
139 | my ($ref, $depth) = @_; |
| 109 | @_ = (); |
140 | @_ = (); |
| 110 | |
141 | |
| … | |
… | |
| 118 | |
149 | |
| 119 | if ($depth) { |
150 | if ($depth) { |
| 120 | my (@about) = find $$refref; |
151 | my (@about) = find $$refref; |
| 121 | if (@about) { |
152 | if (@about) { |
| 122 | for my $about (@about) { |
153 | for my $about (@about) { |
| 123 | $buf .= (" ") x $indent; |
154 | $about->[0] =~ s/([^\x20-\x7e])/sprintf "\\{%02x}", ord $1/ge; |
| 124 | $buf .= $about->[0]; |
155 | $buf .= "$indent" . (@about > 1 ? "+- " : "") . $about->[0]; |
| 125 | if (@$about > 1) { |
156 | if (@$about > 1) { |
| 126 | if ($seen{$about->[1]+0}++) { |
157 | if ($seen{ref2ptr $about->[1]}++) { |
| 127 | $buf .= " $about->[1], which was seen before.\n"; |
158 | $buf .= " " . (_f $about->[1]) . ", which was seen before.\n"; |
| 128 | } else { |
159 | } else { |
| 129 | $buf .= " $about->[1], which is\n"; |
160 | $buf .= " " . (_f $about->[1]) . ", which is\n"; |
| 130 | $track->(\$about->[1], $depth - 1, $indent + 1); |
161 | $track->(\$about->[1], $depth - 1, $about == $about[-1] ? "$indent " : "$indent| "); |
| 131 | } |
162 | } |
| 132 | } else { |
163 | } else { |
| 133 | $buf .= ".\n"; |
164 | $buf .= ".\n"; |
| 134 | } |
165 | } |
| 135 | } |
166 | } |
| 136 | } else { |
167 | } else { |
| 137 | $buf .= (" ") x $indent; |
|
|
| 138 | $buf .= "not found anywhere I looked :(\n"; |
168 | $buf .= "$indent not found anywhere I looked :(\n"; |
| 139 | } |
169 | } |
| 140 | } else { |
170 | } else { |
| 141 | $buf .= (" ") x $indent; |
|
|
| 142 | $buf .= "not referenced within the search depth.\n"; |
171 | $buf .= "$indent not referenced within the search depth.\n"; |
| 143 | } |
172 | } |
| 144 | }; |
173 | }; |
| 145 | |
174 | |
| 146 | $buf .= "$ref is\n"; |
175 | $buf .= (_f $ref) . " is\n"; |
| 147 | $track->(\$ref, $depth || 10, 1); |
176 | |
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|
177 | $track->(\$ref, $depth || $ENV{PERL_DEVEL_FINDREF_DEPTH} || 10, ""); |
| 148 | $buf |
178 | $buf |
| 149 | } |
179 | } |
| 150 | |
180 | |
| 151 | =item @references = Devel::FindRef::find $ref |
181 | =item @references = Devel::FindRef::find $ref |
| 152 | |
182 | |
| … | |
… | |
| 161 | =cut |
191 | =cut |
| 162 | |
192 | |
| 163 | sub find($) { |
193 | sub find($) { |
| 164 | my ($about, $excl) = &find_; |
194 | my ($about, $excl) = &find_; |
| 165 | my %excl = map +($_ => undef), @$excl; |
195 | my %excl = map +($_ => undef), @$excl; |
| 166 | grep !exists $excl{$_->[1] + 0}, @$about |
196 | grep !($#$_ && exists $excl{ref2ptr $_->[1]}), @$about |
| 167 | } |
197 | } |
| 168 | |
198 | |
| 169 | =item $ref = Devel::FindRef::ptr2ref $integer |
199 | =item $ref = Devel::FindRef::ptr2ref $integer |
| 170 | |
200 | |
| 171 | Sometimes you know (from debugging output) the address of a perl scalar |
201 | Sometimes you know (from debugging output) the address of a perl value you |
| 172 | you are interested in (e.g. C<HASH(0x176ff70)>). This function can be used |
202 | are interested in (e.g. C<HASH(0x176ff70)>). This function can be used to |
| 173 | to turn the address into a reference to that scalar. It is quite safe to |
203 | turn the address into a reference to that value. It is quite safe to call |
| 174 | call on valid addresses, but extremely dangerous to call on invalid ones. |
204 | on valid addresses, but extremely dangerous to call on invalid ones. I<No |
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205 | checks whatsoever will be done>, so don't use this unless you really know |
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206 | the value is the address of a valid perl value. |
| 175 | |
207 | |
| 176 | # we know that HASH(0x176ff70) exists, so turn it into a hashref: |
208 | # we know that HASH(0x176ff70) exists, so turn it into a hashref: |
| 177 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
209 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
| 178 | |
210 | |
|
|
211 | =item $ptr = Devel::FindRef::ref2ptr $reference |
|
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212 | |
|
|
213 | The opposite of C<ptr2ref>, above: returns the internal address of the |
|
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214 | value pointed to by the passed reference. This function is safe to call on |
|
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215 | anything, and returns the same value that a normal reference would if used |
|
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216 | in a numeric context. |
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217 | |
| 179 | =back |
218 | =back |
| 180 | |
219 | |
|
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220 | =head1 ENVIRONMENT VARIABLES |
|
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221 | |
|
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222 | You can set the environment variable C<PERL_DEVEL_FINDREF_DEPTH> to an |
|
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223 | integer to override the default depth in C<track>. If a call explicitly |
|
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224 | specifies a depth, it is not overridden. |
|
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225 | |
| 181 | =head1 AUTHOR |
226 | =head1 AUTHOR |
| 182 | |
227 | |
| 183 | Marc Lehmann <pcg@goof.com>. |
228 | Marc Lehmann <pcg@goof.com>. |
| 184 | |
229 | |
| 185 | =head1 BUGS |
|
|
| 186 | |
|
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| 187 | Only code values, arrays, hashes, scalars and magic are being looked at. |
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| 188 | |
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| 189 | This is a quick hack only. |
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| 190 | |
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| 191 | =head1 COPYRIGHT AND LICENSE |
230 | =head1 COPYRIGHT AND LICENSE |
| 192 | |
231 | |
| 193 | Copyright (C) 2007 by Marc Lehmann. |
232 | Copyright (C) 2007, 2008, 2009, 2013 by Marc Lehmann. |
| 194 | |
233 | |
| 195 | This library is free software; you can redistribute it and/or modify |
234 | This library is free software; you can redistribute it and/or modify |
| 196 | it under the same terms as Perl itself, either Perl version 5.8.8 or, |
235 | it under the same terms as Perl itself, either Perl version 5.8.8 or, |
| 197 | at your option, any later version of Perl 5 you may have available. |
236 | at your option, any later version of Perl 5 you may have available. |
| 198 | |
237 | |
