| 1 |
package Devel::FindRef; |
| 2 |
|
| 3 |
use strict; |
| 4 |
|
| 5 |
use XSLoader; |
| 6 |
|
| 7 |
|
| 8 |
BEGIN { |
| 9 |
our $VERSION = '0.1'; |
| 10 |
XSLoader::load __PACKAGE__, $VERSION; |
| 11 |
} |
| 12 |
|
| 13 |
=head1 NAME |
| 14 |
|
| 15 |
Devel::FindRef - where is that reference to my scalar hiding? |
| 16 |
|
| 17 |
=head1 SYNOPSIS |
| 18 |
|
| 19 |
use Devel::FindRef; |
| 20 |
|
| 21 |
=head1 DESCRIPTION |
| 22 |
|
| 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 |
| 25 |
be very hard, although perl keeps track of all values. |
| 26 |
|
| 27 |
The C<track> function can hlep track down some of those refernces back to |
| 28 |
the variables containing them. |
| 29 |
|
| 30 |
For example, for this fragment: |
| 31 |
|
| 32 |
package Test; |
| 33 |
|
| 34 |
our $var = "hi\n"; |
| 35 |
my $x = \$var; |
| 36 |
our %hash = (ukukey => \$var); |
| 37 |
our $hash2 = {ukukey2 => \$var}; |
| 38 |
|
| 39 |
sub testsub { |
| 40 |
my $local = $hash2; |
| 41 |
print Devel::FindRef::track \$var; |
| 42 |
} |
| 43 |
|
| 44 |
testsub; |
| 45 |
|
| 46 |
The output is as follows (or similar to htis, in case I forget to update |
| 47 |
the manpage afetr some changes): |
| 48 |
|
| 49 |
SCALAR(0x676fa0) is |
| 50 |
referenced by REF(0x676fb0), which is |
| 51 |
in the lexical '$x' in CODE(0x676370), which is |
| 52 |
not found anywhere I looked :( |
| 53 |
referenced by REF(0x676360), which is |
| 54 |
in the member 'ukukey' of HASH(0x756660), which is |
| 55 |
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 $Test::hash2. |
| 64 |
|
| 65 |
|
| 66 |
It is a bit convoluted to read, but basically it says that the value stored in C<$var> |
| 67 |
can be found: |
| 68 |
|
| 69 |
=over 4 |
| 70 |
|
| 71 |
=item - in some variable C<$x> whose origin is not known (I frankly have no |
| 72 |
idea why, hints accepted). |
| 73 |
|
| 74 |
=item - in the hash element with key C<ukukey> in the hash stored in C<%Test::hash>. |
| 75 |
|
| 76 |
=item - in the global variable named C<$Test::var>. |
| 77 |
|
| 78 |
=item - in the hash element C<ukukey2>, in the hash in the my variable |
| 79 |
C<$local> in the sub C<Test::testsub> and also in the hash referenced by |
| 80 |
C<$Test::hash2>. |
| 81 |
|
| 82 |
=head1 EXPORTS |
| 83 |
|
| 84 |
None. |
| 85 |
|
| 86 |
=head1 FUNCTIONS |
| 87 |
|
| 88 |
=over 4 |
| 89 |
|
| 90 |
=item $string = Devel::FindRef::track $ref[, $depth] |
| 91 |
|
| 92 |
Track the perl value pointed to by C<$ref> up to a depth of C<$depth> and |
| 93 |
return a descriptive string. C<$ref> can point at any perl value, be it |
| 94 |
anonymous sub, hash, array, scalar etc. |
| 95 |
|
| 96 |
This is the function you most often use. |
| 97 |
|
| 98 |
=cut |
| 99 |
|
| 100 |
sub find($); |
| 101 |
|
| 102 |
sub track { |
| 103 |
my $buf = ""; |
| 104 |
|
| 105 |
my $track; $track = sub { |
| 106 |
my (undef, $depth, $indent) = @_; |
| 107 |
|
| 108 |
if ($depth) { |
| 109 |
my (@about) = find $_[0]; |
| 110 |
if (@about) { |
| 111 |
for my $about (@about) { |
| 112 |
$buf .= (" ") x $indent; |
| 113 |
$buf .= $about->[0]; |
| 114 |
if (@$about > 1) { |
| 115 |
$buf .= " $about->[1], which is\n"; |
| 116 |
$track->($about->[1], $depth - 1, $indent + 1); |
| 117 |
} else { |
| 118 |
$buf .= ".\n"; |
| 119 |
} |
| 120 |
} |
| 121 |
} else { |
| 122 |
$buf .= (" ") x $indent; |
| 123 |
$buf .= "not found anywhere I looked :(\n"; |
| 124 |
} |
| 125 |
} else { |
| 126 |
$buf .= (" ") x $indent; |
| 127 |
$buf .= "not referenced within the search depth.\n"; |
| 128 |
} |
| 129 |
}; |
| 130 |
|
| 131 |
$buf .= "$_[0] is\n"; |
| 132 |
$track->($_[0], $_[1] || 10, 1); |
| 133 |
$buf |
| 134 |
} |
| 135 |
|
| 136 |
=item @references = Devel::FindRef::find $ref |
| 137 |
|
| 138 |
Return arrayrefs that contain [$message, $ref] pairs. The message |
| 139 |
describes what kind of reference was found and the C<$ref> is the |
| 140 |
reference itself, which cna be omitted if C<find> decided to end the |
| 141 |
search. |
| 142 |
|
| 143 |
The C<track> function uses this to find references to the value you are |
| 144 |
interested in and recurses on the returned references. |
| 145 |
|
| 146 |
=cut |
| 147 |
|
| 148 |
sub find($) { |
| 149 |
my ($about, $excl) = &find_; |
| 150 |
my %excl = map +($_ => 1), @$excl; |
| 151 |
grep !$excl{$_->[1] + 0}, @$about |
| 152 |
} |
| 153 |
|
| 154 |
=item $ref = Devel::FindRef::ref2ptr $ptr |
| 155 |
|
| 156 |
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 |
| 158 |
a reference to that scalar. It is quite safe to call on valid addresses, |
| 159 |
but extremely dangerous to call on invalid ones. |
| 160 |
|
| 161 |
=back |
| 162 |
|
| 163 |
=head1 AUTHOR |
| 164 |
|
| 165 |
Marc Lehmann <pcg@goof.com>. |
| 166 |
|
| 167 |
=head1 BUGS |
| 168 |
|
| 169 |
Only code values, arrays, hashes and scalars are being looked at. Tied |
| 170 |
values and magic is not currently being investigated. |
| 171 |
|
| 172 |
=head1 COPYRIGHT AND LICENSE |
| 173 |
|
| 174 |
Copyright (C) 2007 by Marc Lehmann. |
| 175 |
|
| 176 |
This library is free software; you can redistribute it and/or modify |
| 177 |
it under the same terms as Perl itself, either Perl version 5.8.8 or, |
| 178 |
at your option, any later version of Perl 5 you may have available. |
| 179 |
|
| 180 |
=cut |
| 181 |
|
| 182 |
1 |
| 183 |
|
