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 | |
7 | use Scalar::Util; |
7 | |
8 | |
8 | BEGIN { |
9 | BEGIN { |
9 | our $VERSION = '0.1'; |
10 | our $VERSION = '1.31'; |
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; |
20 | |
21 | |
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22 | print Devel::FindRef::track \$some_variable; |
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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 |
27 | 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. |
28 | very hard. Fortunately, perl keeps track of all its values, so tracking |
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29 | references "backwards" is usually possible. |
26 | |
30 | |
27 | The C<track> function can hlep track down some of those refernces back to |
31 | The C<track> function can help track down some of those references back to |
28 | the variables containing them. |
32 | the variables containing them. |
29 | |
33 | |
30 | For example, for this fragment: |
34 | For example, for this fragment: |
31 | |
35 | |
32 | package Test; |
36 | package Test; |
… | |
… | |
41 | print Devel::FindRef::track \$var; |
45 | print Devel::FindRef::track \$var; |
42 | } |
46 | } |
43 | |
47 | |
44 | testsub; |
48 | testsub; |
45 | |
49 | |
46 | The output is as follows (or similar to htis, in case I forget to update |
50 | The output is as follows (or similar to this, in case I forget to update |
47 | the manpage afetr some changes): |
51 | the manpage after some changes): |
48 | |
52 | |
49 | SCALAR(0x676fa0) is |
53 | SCALAR(0x814ece8) is |
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54 | +- in the global $Test::var. |
50 | referenced by REF(0x676fb0), which is |
55 | +- referenced by REF(0x814f9e4), which is |
51 | in the lexical '$x' in CODE(0x676370), which is |
56 | | in the lexical '$x' in CODE(0x814ed78), which is |
52 | not found anywhere I looked :( |
57 | | the containing scope for CODE(0x820c4b0), which is |
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58 | | in the global &Test::testsub. |
53 | referenced by REF(0x676360), which is |
59 | +- referenced by REF(0x814ed6c), which is |
54 | in the member 'ukukey' of HASH(0x756660), which is |
60 | | in the member 'ukukey' of HASH(0x81da20c), which is |
55 | in the global %Test::hash. |
61 | | in the global %Test::hash. |
56 | in the global $Test::var. |
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57 | referenced by REF(0x6760e0), which is |
62 | +- referenced by REF(0x814ec28), which is |
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63 | | not found anywhere I looked :( |
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64 | +- referenced by REF(0x814eb44), which is |
58 | in the member 'ukukey2' of HASH(0x676f30), which is |
65 | in the member 'ukukey2' of HASH(0x814f99c), which is |
59 | referenced by REF(0x77bcf0), which is |
66 | +- referenced by REF(0x820c450), which is |
60 | in the lexical '$local' in CODE(0x77bcb0), which is |
67 | | in the lexical '$local' in CODE(0x820c4b0), which was seen before. |
61 | in the global &Test::testsub. |
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62 | referenced by REF(0x77bc80), which is |
68 | +- referenced by REF(0x820c204), which is |
63 | in the global $Test::hash2. |
69 | in the global $Test::hash2. |
64 | |
70 | |
65 | |
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66 | It is a bit convoluted to read, but basically it says that the value stored in C<$var> |
71 | It is a bit convoluted to read, but basically it says that the value |
67 | can be found: |
72 | stored in C<$var> can be found: |
68 | |
73 | |
69 | =over 4 |
74 | =over 4 |
70 | |
75 | |
71 | =item - in some variable C<$x> whose origin is not known (I frankly have no |
76 | =item - in some variable C<$x> whose origin is not known (I frankly have no |
72 | idea why, hints accepted). |
77 | idea why, hints accepted). |
… | |
… | |
77 | |
82 | |
78 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
83 | =item - in the hash element C<ukukey2>, in the hash in the my variable |
79 | C<$local> in the sub C<Test::testsub> and also in the hash referenced by |
84 | C<$local> in the sub C<Test::testsub> and also in the hash referenced by |
80 | C<$Test::hash2>. |
85 | C<$Test::hash2>. |
81 | |
86 | |
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|
87 | =back |
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88 | |
82 | =head1 EXPORTS |
89 | =head1 EXPORTS |
83 | |
90 | |
84 | None. |
91 | None. |
85 | |
92 | |
86 | =head1 FUNCTIONS |
93 | =head1 FUNCTIONS |
… | |
… | |
98 | =cut |
105 | =cut |
99 | |
106 | |
100 | sub find($); |
107 | sub find($); |
101 | |
108 | |
102 | sub track { |
109 | sub track { |
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110 | my ($ref, $depth) = @_; |
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111 | @_ = (); |
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112 | |
103 | my $buf = ""; |
113 | my $buf = ""; |
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114 | my %seen; |
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115 | |
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116 | Scalar::Util::weaken $ref; |
104 | |
117 | |
105 | my $track; $track = sub { |
118 | my $track; $track = sub { |
106 | my (undef, $depth, $indent) = @_; |
119 | my ($refref, $depth, $indent) = @_; |
107 | |
120 | |
108 | if ($depth) { |
121 | if ($depth) { |
109 | my (@about) = find $_[0]; |
122 | my (@about) = find $$refref; |
110 | if (@about) { |
123 | if (@about) { |
111 | for my $about (@about) { |
124 | for my $about (@about) { |
112 | $buf .= (" ") x $indent; |
125 | $buf .= "$indent" . (@about > 1 ? "+- " : " ") . $about->[0]; |
113 | $buf .= $about->[0]; |
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114 | if (@$about > 1) { |
126 | if (@$about > 1) { |
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127 | if ($seen{ref2ptr $about->[1]}++) { |
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128 | $buf .= " $about->[1], which was seen before.\n"; |
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129 | } else { |
115 | $buf .= " $about->[1], which is\n"; |
130 | $buf .= " $about->[1], which is\n"; |
116 | $track->($about->[1], $depth - 1, $indent + 1); |
131 | $track->(\$about->[1], $depth - 1, $about == $about[-1] ? "$indent " : "$indent| "); |
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132 | } |
117 | } else { |
133 | } else { |
118 | $buf .= ".\n"; |
134 | $buf .= ".\n"; |
119 | } |
135 | } |
120 | } |
136 | } |
121 | } else { |
137 | } else { |
122 | $buf .= (" ") x $indent; |
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123 | $buf .= "not found anywhere I looked :(\n"; |
138 | $buf .= "$indent not found anywhere I looked :(\n"; |
124 | } |
139 | } |
125 | } else { |
140 | } else { |
126 | $buf .= (" ") x $indent; |
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127 | $buf .= "not referenced within the search depth.\n"; |
141 | $buf .= "$indent not referenced within the search depth.\n"; |
128 | } |
142 | } |
129 | }; |
143 | }; |
130 | |
144 | |
131 | $buf .= "$_[0] is\n"; |
145 | $buf .= "$ref is\n"; |
132 | $track->($_[0], $_[1] || 10, 1); |
146 | $track->(\$ref, $depth || $ENV{PERL_DEVEL_FINDREF_DEPTH} || 10, ""); |
133 | $buf |
147 | $buf |
134 | } |
148 | } |
135 | |
149 | |
136 | =item @references = Devel::FindRef::find $ref |
150 | =item @references = Devel::FindRef::find $ref |
137 | |
151 | |
138 | Return arrayrefs that contain [$message, $ref] pairs. The message |
152 | Return arrayrefs that contain [$message, $ref] pairs. The message |
139 | describes what kind of reference was found and the C<$ref> is the |
153 | describes what kind of reference was found and the C<$ref> is the |
140 | reference itself, which cna be omitted if C<find> decided to end the |
154 | reference itself, which can be omitted if C<find> decided to end the |
141 | search. |
155 | search. The returned references are all weak references. |
142 | |
156 | |
143 | The C<track> function uses this to find references to the value you are |
157 | The C<track> function uses this to find references to the value you are |
144 | interested in and recurses on the returned references. |
158 | interested in and recurses on the returned references. |
145 | |
159 | |
146 | =cut |
160 | =cut |
147 | |
161 | |
148 | sub find($) { |
162 | sub find($) { |
149 | my ($about, $excl) = &find_; |
163 | my ($about, $excl) = &find_; |
150 | my %excl = map +($_ => 1), @$excl; |
164 | my %excl = map +($_ => undef), @$excl; |
151 | grep !$excl{$_->[1] + 0}, @$about |
165 | grep !exists $excl{ref2ptr $_->[1]}, @$about |
152 | } |
166 | } |
153 | |
167 | |
154 | =item $ref = Devel::FindRef::ref2ptr $ptr |
168 | =item $ref = Devel::FindRef::ptr2ref $integer |
155 | |
169 | |
156 | Sometimes you know (from debugging output) the address of a perl scalar |
170 | 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 |
171 | 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, |
172 | to turn the address into a reference to that scalar. It is quite safe to |
159 | but extremely dangerous to call on invalid ones. |
173 | call on valid addresses, but extremely dangerous to call on invalid ones. |
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174 | |
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175 | # we know that HASH(0x176ff70) exists, so turn it into a hashref: |
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176 | my $ref_to_hash = Devel::FindRef::ptr2ref 0x176ff70; |
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177 | |
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178 | =item $ref = Devel::FindRef::ref2ptr $reference |
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179 | |
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180 | The opposite of C<ptr2ref>, above: returns the internal address of the |
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181 | value pointed to by the passed reference. I<No checks whatsoever will be |
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182 | done>, so don't use this. |
160 | |
183 | |
161 | =back |
184 | =back |
162 | |
185 | |
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186 | =head1 ENVIRONMENT VARIABLES |
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187 | |
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188 | You can set the environment variable C<PERL_DEVEL_FINDREF_DEPTH> to an |
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189 | integer to override the default depth in C<track>. If a call explicitly |
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190 | specified a depth it is not overridden. |
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191 | |
163 | =head1 AUTHOR |
192 | =head1 AUTHOR |
164 | |
193 | |
165 | Marc Lehmann <pcg@goof.com>. |
194 | Marc Lehmann <pcg@goof.com>. |
166 | |
195 | |
167 | =head1 BUGS |
196 | =head1 BUGS |
168 | |
197 | |
169 | Only code values, arrays, hashes and scalars are being looked at. Tied |
198 | Only code values, arrays, hashes, scalars and magic are being looked at. |
170 | values and magic is not currently being investigated. |
199 | |
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200 | This is a quick hack only. |
171 | |
201 | |
172 | =head1 COPYRIGHT AND LICENSE |
202 | =head1 COPYRIGHT AND LICENSE |
173 | |
203 | |
174 | Copyright (C) 2007 by Marc Lehmann. |
204 | Copyright (C) 2007 by Marc Lehmann. |
175 | |
205 | |