/usr/lib/perl5/DBD/Gofer/Transport/corostream.pm is in libdbi-perl 1.616-1build2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 | package DBD::Gofer::Transport::corostream;
use strict;
use warnings;
use Carp;
use Coro::Select; # a slow but coro-aware replacement for CORE::select (global effect!)
use Coro;
use Coro::Handle;
use base qw(DBD::Gofer::Transport::stream);
# XXX ensure DBI_PUREPERL for parent doesn't pass to child
sub start_pipe_command {
local $ENV{DBI_PUREPERL} = $ENV{DBI_PUREPERL_COROCHILD}; # typically undef
my $connection = shift->SUPER::start_pipe_command(@_);
return $connection;
}
1;
__END__
=head1 NAME
DBD::Gofer::Transport::corostream - Async DBD::Gofer stream transport using Coro and AnyEvent
=head1 SYNOPSIS
DBI_AUTOPROXY="dbi:Gofer:transport=corostream" perl some-perl-script-using-dbi.pl
or
$dsn = ...; # the DSN for the driver and database you want to use
$dbh = DBI->connect("dbi:Gofer:transport=corostream;dsn=$dsn", ...);
=head1 DESCRIPTION
The I<BIG WIN> from using L<Coro> is that it enables the use of existing
DBI frameworks like L<DBIx::Class>.
=head1 KNOWN ISSUES AND LIMITATIONS
- Uses Coro::Select so alters CORE::select globally
Parent class probably needs refactoring to enable a more encapsulated approach.
- Doesn't prevent multiple concurrent requests
Probably just needs a per-connection semaphore
- Coro has many caveats. Caveat emptor.
=head1 STATUS
THIS IS CURRENTLY JUST A PROOF-OF-CONCEPT IMPLEMENTATION FOR EXPERIMENTATION.
Please note that I have no plans to develop this code further myself.
I'd very much welcome contributions. Interested? Let me know!
=head1 AUTHOR
Tim Bunce, L<http://www.tim.bunce.name>
=head1 LICENCE AND COPYRIGHT
Copyright (c) 2010, Tim Bunce, Ireland. All rights reserved.
This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself. See L<perlartistic>.
=head1 SEE ALSO
L<DBD::Gofer::Transport::stream>
L<DBD::Gofer>
=head1 APPENDIX
Example code:
#!perl
use strict;
use warnings;
use Time::HiRes qw(time);
BEGIN { $ENV{PERL_ANYEVENT_STRICT} = 1; $ENV{PERL_ANYEVENT_VERBOSE} = 1; }
use AnyEvent;
BEGIN { $ENV{DBI_TRACE} = 0; $ENV{DBI_GOFER_TRACE} = 0; $ENV{DBD_GOFER_TRACE} = 0; };
use DBI;
$ENV{DBI_AUTOPROXY} = 'dbi:Gofer:transport=corostream';
my $ticker = AnyEvent->timer( after => 0, interval => 0.1, cb => sub {
warn sprintf "-tick- %.2f\n", time
} );
warn "connecting...\n";
my $dbh = DBI->connect("dbi:NullP:");
warn "...connected\n";
for (1..3) {
warn "entering DBI...\n";
$dbh->do("sleep 0.3"); # pseudo-sql understood by the DBD::NullP driver
warn "...returned\n";
}
warn "done.";
Example output:
$ perl corogofer.pl
connecting...
-tick- 1293631437.14
-tick- 1293631437.14
...connected
entering DBI...
-tick- 1293631437.25
-tick- 1293631437.35
-tick- 1293631437.45
-tick- 1293631437.55
...returned
entering DBI...
-tick- 1293631437.66
-tick- 1293631437.76
-tick- 1293631437.86
...returned
entering DBI...
-tick- 1293631437.96
-tick- 1293631438.06
-tick- 1293631438.16
...returned
done. at corogofer.pl line 39.
You can see that the timer callback is firing while the code 'waits' inside the
do() method for the response from the database. Normally that would block.
=cut
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