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package Test::Trap::Builder::SystemSafe;
use version; $VERSION = qv('0.2.2');
use strict;
use warnings;
use Test::Trap::Builder;
use File::Temp qw( tempfile );
use IO::Handle;
sub import {
Test::Trap::Builder->output_layer_backend( systemsafe => $_ ) for sub {
my $self = shift;
my ($name, $fileno, $globref) = @_;
my $pid = $$;
if (tied *$globref or $fileno < 0) {
$self->Exception("SystemSafe only works with real file descriptors; aborting");
}
my ($fh, $file) = tempfile( UNLINK => 1 ); # XXX: Test?
my ($fh_keeper, $autoflush_keeper);
$self->Teardown($_) for sub {
if ($pid == $$) {
# this process opened it, so it gets to collect the contents:
local $/;
$self->{$name} .= $fh->getline;
close $fh; # don't leak this one either!
unlink $file;
}
close *$globref;
return unless $fh_keeper;
# close and reopen the file to the keeper!
my $fno = fileno $fh_keeper;
_close_reopen( $self, $globref, $fileno, ">&$fno",
sub {
close $fh_keeper;
sprintf "Cannot dup '%s' for %s: '%s'",
$fno, $name, $!;
},
);
close $fh_keeper; # another potential leak, I suppose.
$globref->autoflush($autoflush_keeper);
};
binmode $fh; # superfluos?
open $fh_keeper, ">&$fileno"
or $self->Exception("Cannot dup '$fileno' for $name: '$!'");
$autoflush_keeper = $globref->autoflush;
_close_reopen( $self, $globref, $fileno, ">>$file",
sub {
sprintf "Cannot open %s for %s: '%s'",
$file, $name, $!;
},
);
binmode *$globref; # must write with the same mode as we read.
$globref->autoflush(1);
$self->Next;
};
}
sub _close_reopen {
my ($result, $glob, $fno_want, $what, $err) = @_;
close *$glob;
my @fh;
while (1) {
no warnings 'io';
open *$glob, $what or $result->Exception($err->());
my $fileno = fileno *$glob;
last if $fileno == $fno_want;
close *$glob;
if ($fileno > $fno_want) {
$result->Exception("Cannot get the desired descriptor, '$fno_want' (could it be that it is fdopened and so still open?)");
}
if (grep{$fileno == fileno($_)}@fh) {
$result->Exception("Getting several files opened on fileno $fileno");
}
open my $fh, $what or $result->Exception($err->());
if (fileno($fh) != $fileno) {
$result->Exception("Getting fileno " . fileno($fh) . "; expecting $fileno");
}
push @fh, $fh;
}
close $_ for @fh;
}
1; # End of Test::Trap::Builder::SystemSafe
__END__
=head1 NAME
Test::Trap::Builder::SystemSafe - "Safe" output layer backend using File::Temp
=head1 VERSION
Version 0.2.2
=head1 DESCRIPTION
This module provides an implementation I<systemsafe>, based on
File::Temp, for the trap's output layers. This implementation insists
on reopening the output file handles with the same descriptors, and
therefore, unlike L<Test::Trap::Builder::TempFile> and
L<Test::Trap::Builder::PerlIO>, is able to trap output from forked-off
processes, including system().
See also L<Test::Trap> (:stdout and :stderr) and
L<Test::Trap::Builder> (output_layer).
=head1 CAVEATS
Using File::Temp, we need privileges to create tempfiles.
We need disk space for the output of every trap (it should clean up
after the trap is sprung).
Disk access may be slow -- certainly compared to the in-memory files
of PerlIO.
If the file handle we try to trap using this backend is on an
in-memory file, it would not be availible to other processes in any
case. Rather than change the semantics of the trapped code or
silently fail to trap output from forked-off processes, we just raise
an exception in this case.
If there is another file handle with the same descriptor (f ex after
an C<< open OTHER, '>&=', THIS >>), we can't get that file descriptor.
Rather than silently fail, we again raise an exception.
Threads? No idea. It might even work correctly.
=head1 BUGS
Please report any bugs or feature requests directly to the author.
=head1 AUTHOR
Eirik Berg Hanssen, C<< <ebhanssen@allverden.no> >>
=head1 COPYRIGHT & LICENSE
Copyright 2006-2012 Eirik Berg Hanssen, All Rights Reserved.
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut
|
