| 1 | package Devel::FindRef; |
1 | package Devel::FindRef; |
| 2 | |
2 | |
| 3 | use strict; |
3 | use strict; |
| 4 | |
4 | |
| 5 | use XSLoader; |
5 | use XSLoader; |
| 6 | |
6 | use Scalar::Util; |
| 7 | |
7 | |
| 8 | BEGIN { |
8 | BEGIN { |
| 9 | our $VERSION = '0.1'; |
9 | our $VERSION = '1.2'; |
| 10 | XSLoader::load __PACKAGE__, $VERSION; |
10 | XSLoader::load __PACKAGE__, $VERSION; |
| 11 | } |
11 | } |
| 12 | |
12 | |
| 13 | =head1 NAME |
13 | =head1 NAME |
| 14 | |
14 | |
| … | |
… | |
| 19 | use Devel::FindRef; |
19 | use Devel::FindRef; |
| 20 | |
20 | |
| 21 | =head1 DESCRIPTION |
21 | =head1 DESCRIPTION |
| 22 | |
22 | |
| 23 | Tracking down reference problems (e.g. you expect some object to be |
23 | 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 |
24 | destroyed, but there are still references to it that keep it alive) can be |
| 25 | be very hard, although perl keeps track of all values. |
25 | very hard. Fortunately, perl keeps track of all its values, so tracking |
|
|
26 | references "backwards" is usually possible. |
| 26 | |
27 | |
| 27 | The C<track> function can hlep track down some of those refernces back to |
28 | The C<track> function can help track down some of those references back to |
| 28 | the variables containing them. |
29 | the variables containing them. |
| 29 | |
30 | |
| 30 | For example, for this fragment: |
31 | For example, for this fragment: |
| 31 | |
32 | |
| 32 | package Test; |
33 | package Test; |
| … | |
… | |
| 41 | print Devel::FindRef::track \$var; |
42 | print Devel::FindRef::track \$var; |
| 42 | } |
43 | } |
| 43 | |
44 | |
| 44 | testsub; |
45 | testsub; |
| 45 | |
46 | |
| 46 | The output is as follows (or similar to htis, in case I forget to update |
47 | The output is as follows (or similar to this, in case I forget to update |
| 47 | the manpage afetr some changes): |
48 | the manpage after some changes): |
| 48 | |
49 | |
| 49 | SCALAR(0x676fa0) is |
50 | SCALAR(0x7bd2d0) is |
|
|
51 | in the global $Test::var. |
| 50 | referenced by REF(0x676fb0), which is |
52 | referenced by REF(0x7bd240), which is |
|
|
53 | in the member 'ukukey2' of HASH(0x7bd228), which is |
|
|
54 | referenced by REF(0x81dae8), which is |
|
|
55 | in the lexical '$local' in CODE(0x81da88), which is |
|
|
56 | in the global &Test::testsub. |
|
|
57 | referenced by REF(0x81da40), which is |
|
|
58 | in the global $Test::hash2. |
|
|
59 | referenced by REF(0x79f3f8), which is |
| 51 | in the lexical '$x' in CODE(0x676370), which is |
60 | in the lexical '$x' in CODE(0x79f518), which is |
|
|
61 | the containing scope for CODE(0x81da88), which is |
|
|
62 | in the global &Test::testsub. |
|
|
63 | referenced by REF(0x79f2f0), which is |
| 52 | not found anywhere I looked :( |
64 | not found anywhere I looked :( |
| 53 | referenced by REF(0x676360), which is |
65 | referenced by REF(0x79f140), which is |
| 54 | in the member 'ukukey' of HASH(0x756660), which is |
66 | in the member 'ukukey' of HASH(0x81d698), which is |
| 55 | in the global %Test::hash. |
67 | in the global %Test::hash. |
| 56 | in the global $Test::var. |
|
|
| 57 | referenced by REF(0x6760e0), which is |
|
|
| 58 | in the member 'ukukey2' of HASH(0x676f30), which is |
|
|
| 59 | referenced by REF(0x77bcf0), which is |
|
|
| 60 | in the lexical '$local' in CODE(0x77bcb0), which is |
|
|
| 61 | in the global &Test::testsub. |
|
|
| 62 | referenced by REF(0x77bc80), which is |
|
|
| 63 | in the global $Test::hash2. |
|
|
| 64 | |
68 | |
| 65 | |
|
|
| 66 | It is a bit convoluted to read, but basically it says that the value stored in C<$var> |
69 | It is a bit convoluted to read, but basically it says that the value |
| 67 | can be found: |
70 | stored in C<$var> can be found: |
| 68 | |
71 | |
| 69 | =over 4 |
72 | =over 4 |
| 70 | |
73 | |
| 71 | =item - in some variable C<$x> whose origin is not known (I frankly have no |
74 | =item - in some variable C<$x> whose origin is not known (I frankly have no |
| 72 | idea why, hints accepted). |
75 | idea why, hints accepted). |
| … | |
… | |
| 77 | |
80 | |
| 78 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
81 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
| 79 | C<$local> in the sub C<Test::testsub> and also in the hash referenced by |
82 | C<$local> in the sub C<Test::testsub> and also in the hash referenced by |
| 80 | C<$Test::hash2>. |
83 | C<$Test::hash2>. |
| 81 | |
84 | |
|
|
85 | =back |
|
|
86 | |
| 82 | =head1 EXPORTS |
87 | =head1 EXPORTS |
| 83 | |
88 | |
| 84 | None. |
89 | None. |
| 85 | |
90 | |
| 86 | =head1 FUNCTIONS |
91 | =head1 FUNCTIONS |
| … | |
… | |
| 98 | =cut |
103 | =cut |
| 99 | |
104 | |
| 100 | sub find($); |
105 | sub find($); |
| 101 | |
106 | |
| 102 | sub track { |
107 | sub track { |
|
|
108 | my ($ref, $depth) = @_; |
|
|
109 | @_ = (); |
|
|
110 | |
| 103 | my $buf = ""; |
111 | my $buf = ""; |
|
|
112 | my %seen; |
|
|
113 | |
|
|
114 | Scalar::Util::weaken $ref; |
| 104 | |
115 | |
| 105 | my $track; $track = sub { |
116 | my $track; $track = sub { |
| 106 | my (undef, $depth, $indent) = @_; |
117 | my ($refref, $depth, $indent) = @_; |
| 107 | |
118 | |
| 108 | if ($depth) { |
119 | if ($depth) { |
| 109 | my (@about) = find $_[0]; |
120 | my (@about) = find $$refref; |
| 110 | if (@about) { |
121 | if (@about) { |
| 111 | for my $about (@about) { |
122 | for my $about (@about) { |
| 112 | $buf .= (" ") x $indent; |
123 | $buf .= "$indent" . (@about > 1 ? "+- " : " ") . $about->[0]; |
| 113 | $buf .= $about->[0]; |
|
|
| 114 | if (@$about > 1) { |
124 | if (@$about > 1) { |
|
|
125 | if ($seen{$about->[1]+0}++) { |
|
|
126 | $buf .= " $about->[1], which was seen before.\n"; |
|
|
127 | } else { |
| 115 | $buf .= " $about->[1], which is\n"; |
128 | $buf .= " $about->[1], which is\n"; |
| 116 | $track->($about->[1], $depth - 1, $indent + 1); |
129 | $track->(\$about->[1], $depth - 1, $about == $about[-1] ? "$indent " : "$indent| "); |
|
|
130 | } |
| 117 | } else { |
131 | } else { |
| 118 | $buf .= ".\n"; |
132 | $buf .= ".\n"; |
| 119 | } |
133 | } |
| 120 | } |
134 | } |
| 121 | } else { |
135 | } else { |
| 122 | $buf .= (" ") x $indent; |
|
|
| 123 | $buf .= "not found anywhere I looked :(\n"; |
136 | $buf .= "$indent not found anywhere I looked :(\n"; |
| 124 | } |
137 | } |
| 125 | } else { |
138 | } else { |
| 126 | $buf .= (" ") x $indent; |
|
|
| 127 | $buf .= "not referenced within the search depth.\n"; |
139 | $buf .= "$indent not referenced within the search depth.\n"; |
| 128 | } |
140 | } |
| 129 | }; |
141 | }; |
| 130 | |
142 | |
| 131 | $buf .= "$_[0] is\n"; |
143 | $buf .= "$ref is\n"; |
| 132 | $track->($_[0], $_[1] || 10, 1); |
144 | $track->(\$ref, $depth || $ENV{PERL_DEVEL_FINDREF_DEPTH} || 10, ""); |
| 133 | $buf |
145 | $buf |
| 134 | } |
146 | } |
| 135 | |
147 | |
| 136 | =item @references = Devel::FindRef::find $ref |
148 | =item @references = Devel::FindRef::find $ref |
| 137 | |
149 | |
| 138 | Return arrayrefs that contain [$message, $ref] pairs. The message |
150 | Return arrayrefs that contain [$message, $ref] pairs. The message |
| 139 | describes what kind of reference was found and the C<$ref> is the |
151 | describes what kind of reference was found and the C<$ref> is the |
| 140 | reference itself, which cna be omitted if C<find> decided to end the |
152 | reference itself, which can be omitted if C<find> decided to end the |
| 141 | search. |
153 | search. The returned references are all weak references. |
| 142 | |
154 | |
| 143 | The C<track> function uses this to find references to the value you are |
155 | The C<track> function uses this to find references to the value you are |
| 144 | interested in and recurses on the returned references. |
156 | interested in and recurses on the returned references. |
| 145 | |
157 | |
| 146 | =cut |
158 | =cut |
| 147 | |
159 | |
| 148 | sub find($) { |
160 | sub find($) { |
| 149 | my ($about, $excl) = &find_; |
161 | my ($about, $excl) = &find_; |
| 150 | my %excl = map +($_ => 1), @$excl; |
162 | my %excl = map +($_ => undef), @$excl; |
| 151 | grep !$excl{$_->[1] + 0}, @$about |
163 | grep !exists $excl{$_->[1] + 0}, @$about |
| 152 | } |
164 | } |
| 153 | |
165 | |
| 154 | =item $ref = Devel::FindRef::ref2ptr $ptr |
166 | =item $ref = Devel::FindRef::ptr2ref $integer |
| 155 | |
167 | |
| 156 | Sometimes you know (from debugging output) the address of a perl scalar |
168 | Sometimes you know (from debugging output) the address of a perl scalar |
| 157 | you are interested in. This function can be used to turn the address into |
169 | you are interested in (e.g. C<HASH(0x176ff70)>). This function can be used |
| 158 | a reference to that scalar. It is quite safe to call on valid addresses, |
170 | to turn the address into a reference to that scalar. It is quite safe to |
| 159 | but extremely dangerous to call on invalid ones. |
171 | call on valid addresses, but extremely dangerous to call on invalid ones. |
|
|
172 | |
|
|
173 | # we know that HASH(0x176ff70) exists, so turn it into a hashref: |
|
|
174 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
| 160 | |
175 | |
| 161 | =back |
176 | =back |
| 162 | |
177 | |
|
|
178 | =head1 ENVIRONMENT VARIABLES |
|
|
179 | |
|
|
180 | You can set the environment variable C<PERL_DEVEL_FINDREF_DEPTH> to an |
|
|
181 | integer to override the default depth in C<track>. If a call explicitly |
|
|
182 | specified a depth it is not overridden. |
|
|
183 | |
| 163 | =head1 AUTHOR |
184 | =head1 AUTHOR |
| 164 | |
185 | |
| 165 | Marc Lehmann <pcg@goof.com>. |
186 | Marc Lehmann <pcg@goof.com>. |
| 166 | |
187 | |
| 167 | =head1 BUGS |
188 | =head1 BUGS |
| 168 | |
189 | |
| 169 | Only code values, arrays, hashes and scalars are being looked at. Tied |
190 | Only code values, arrays, hashes, scalars and magic are being looked at. |
| 170 | values and magic is not currently being investigated. |
191 | |
|
|
192 | This is a quick hack only. |
| 171 | |
193 | |
| 172 | =head1 COPYRIGHT AND LICENSE |
194 | =head1 COPYRIGHT AND LICENSE |
| 173 | |
195 | |
| 174 | Copyright (C) 2007 by Marc Lehmann. |
196 | Copyright (C) 2007 by Marc Lehmann. |
| 175 | |
197 | |
