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 |
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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 after some changes): |
48 | the manpage after some changes): |
48 | |
49 | |
49 | SCALAR(0x676fa0) is |
50 | SCALAR(0x7bd2d0) is |
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51 | in the global $Test::var. |
50 | referenced by REF(0x676fb0), which is |
52 | referenced by REF(0x7bd240), which is |
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53 | in the member 'ukukey2' of HASH(0x7bd228), which is |
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54 | referenced by REF(0x81dae8), which is |
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55 | in the lexical '$local' in CODE(0x81da88), which is |
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56 | in the global &Test::testsub. |
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57 | referenced by REF(0x81da40), which is |
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58 | in the global $Test::hash2. |
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59 | referenced by REF(0x79f3f8), which is |
51 | in the lexical '$x' in CODE(0x676370), which is |
60 | in the lexical '$x' in CODE(0x79f518), which is |
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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 |
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 $Test::var. |
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57 | referenced by REF(0x6760e0), which is |
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58 | in the member 'ukukey2' of HASH(0x676f30), which is |
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59 | referenced by REF(0x77bcf0), which is |
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60 | in the lexical '$local' in CODE(0x77bcb0), which is |
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61 | in the global &Test::testsub. |
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62 | referenced by REF(0x77bc80), which is |
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63 | in the global $Test::hash2. |
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64 | |
68 | |
65 | |
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66 | It is a bit convoluted to read, but basically it says that the value stored in C<$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<$Test::hash2>. |
81 | |
84 | |
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85 | =back |
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86 | |
82 | =head1 EXPORTS |
87 | =head1 EXPORTS |
83 | |
88 | |
84 | None. |
89 | None. |
85 | |
90 | |
86 | =head1 FUNCTIONS |
91 | =head1 FUNCTIONS |
… | |
… | |
98 | =cut |
103 | =cut |
99 | |
104 | |
100 | sub find($); |
105 | sub find($); |
101 | |
106 | |
102 | sub track { |
107 | sub track { |
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108 | my ($ref, $depth) = @_; |
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109 | @_ = (); |
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110 | |
103 | my $buf = ""; |
111 | my $buf = ""; |
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112 | my %seen; |
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113 | |
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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 .= (" ") x $indent; |
113 | $buf .= $about->[0]; |
124 | $buf .= $about->[0]; |
114 | if (@$about > 1) { |
125 | if (@$about > 1) { |
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126 | if ($seen{$about->[1]+0}++) { |
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127 | $buf .= " $about->[1], which was seen before.\n"; |
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128 | } else { |
115 | $buf .= " $about->[1], which is\n"; |
129 | $buf .= " $about->[1], which is\n"; |
116 | $track->($about->[1], $depth - 1, $indent + 1); |
130 | $track->(\$about->[1], $depth - 1, $indent + 1); |
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131 | } |
117 | } else { |
132 | } else { |
118 | $buf .= ".\n"; |
133 | $buf .= ".\n"; |
119 | } |
134 | } |
120 | } |
135 | } |
121 | } else { |
136 | } else { |
… | |
… | |
126 | $buf .= (" ") x $indent; |
141 | $buf .= (" ") x $indent; |
127 | $buf .= "not referenced within the search depth.\n"; |
142 | $buf .= "not referenced within the search depth.\n"; |
128 | } |
143 | } |
129 | }; |
144 | }; |
130 | |
145 | |
131 | $buf .= "$_[0] is\n"; |
146 | $buf .= "$ref is\n"; |
132 | $track->($_[0], $_[1] || 10, 1); |
147 | $track->(\$ref, $depth || 10, 1); |
133 | $buf |
148 | $buf |
134 | } |
149 | } |
135 | |
150 | |
136 | =item @references = Devel::FindRef::find $ref |
151 | =item @references = Devel::FindRef::find $ref |
137 | |
152 | |
138 | Return arrayrefs that contain [$message, $ref] pairs. The message |
153 | Return arrayrefs that contain [$message, $ref] pairs. The message |
139 | describes what kind of reference was found and the C<$ref> is the |
154 | describes what kind of reference was found and the C<$ref> is the |
140 | reference itself, which cna be omitted if C<find> decided to end the |
155 | reference itself, which can be omitted if C<find> decided to end the |
141 | search. |
156 | search. The returned references are all weak references. |
142 | |
157 | |
143 | The C<track> function uses this to find references to the value you are |
158 | The C<track> function uses this to find references to the value you are |
144 | interested in and recurses on the returned references. |
159 | interested in and recurses on the returned references. |
145 | |
160 | |
146 | =cut |
161 | =cut |
147 | |
162 | |
148 | sub find($) { |
163 | sub find($) { |
149 | my ($about, $excl) = &find_; |
164 | my ($about, $excl) = &find_; |
150 | my %excl = map +($_ => 1), @$excl; |
165 | my %excl = map +($_ => undef), @$excl; |
151 | grep !$excl{$_->[1] + 0}, @$about |
166 | grep !exists $excl{$_->[1] + 0}, @$about |
152 | } |
167 | } |
153 | |
168 | |
154 | =item $ref = Devel::FindRef::ref2ptr $ptr |
169 | =item $ref = Devel::FindRef::ptr2ref $integer |
155 | |
170 | |
156 | Sometimes you know (from debugging output) the address of a perl scalar |
171 | 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 |
172 | 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, |
173 | to turn the address into a reference to that scalar. It is quite safe to |
159 | but extremely dangerous to call on invalid ones. |
174 | call on valid addresses, but extremely dangerous to call on invalid ones. |
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175 | |
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176 | # we know that HASH(0x176ff70) exists, so turn it into a hashref: |
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177 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
160 | |
178 | |
161 | =back |
179 | =back |
162 | |
180 | |
163 | =head1 AUTHOR |
181 | =head1 AUTHOR |
164 | |
182 | |
165 | Marc Lehmann <pcg@goof.com>. |
183 | Marc Lehmann <pcg@goof.com>. |
166 | |
184 | |
167 | =head1 BUGS |
185 | =head1 BUGS |
168 | |
186 | |
169 | Only code values, arrays, hashes, scalars and magic are being looked at. |
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. |
170 | |
190 | |
171 | =head1 COPYRIGHT AND LICENSE |
191 | =head1 COPYRIGHT AND LICENSE |
172 | |
192 | |
173 | Copyright (C) 2007 by Marc Lehmann. |
193 | Copyright (C) 2007 by Marc Lehmann. |
174 | |
194 | |