package Wiki::Toolkit::Store::MySQL;
use strict;
use vars qw( @ISA $VERSION );
use Wiki::Toolkit::Store::Database;
use Carp qw/carp croak/;
@ISA = qw( Wiki::Toolkit::Store::Database );
$VERSION = 0.05;
=head1 NAME
Wiki::Toolkit::Store::MySQL - MySQL storage backend for Wiki::Toolkit
=head1 REQUIRES
Subclasses Wiki::Toolkit::Store::Database.
=head1 SYNOPSIS
See Wiki::Toolkit::Store::Database
=cut
# Internal method to return the data source string required by DBI.
sub _dsn {
my ($self, $dbname, $dbhost, $dbport) = @_;
my $dsn = "dbi:mysql:$dbname";
$dsn .= ";host=$dbhost" if $dbhost;
$dsn .= ";port=$dbport" if $dbport;
return $dsn;
}
=head1 METHODS
=over 4
=item B<check_and_write_node>
$store->check_and_write_node( node => $node,
checksum => $checksum,
%other_args );
Locks the node, verifies the checksum, calls
C<write_node_post_locking> with all supplied arguments, unlocks the
node. Returns the version of the updated node on successful writing, 0 if
checksum doesn't match, -1 if the change was not applied, croaks on error.
Note: Uses MySQL's user level locking, so any locks are released when
the database handle disconnects. Doing it like this because I can't seem
to get it to work properly with transactions.
=back
=cut
sub check_and_write_node {
my ($self, %args) = @_;
my ($node, $checksum) = @args{qw( node checksum )};
$self->_lock_node($node) or croak "Can't lock node";
my $ok = $self->verify_checksum($node, $checksum);
unless ($ok) {
$self->_unlock_node($node) or carp "Can't unlock node";
return 0;
}
$ok = $self->write_node_post_locking( %args );
$self->_unlock_node($node) or carp "Can't unlock node";
return $ok;
}
# Returns 1 if we can get a lock, 0 if we can't, croaks on error.
sub _lock_node {
my ($self, $node) = @_;
my $dbh = $self->{_dbh};
$node = $dbh->quote($node);
my $sql = "SELECT GET_LOCK($node, 10)";
my $sth = $dbh->prepare($sql);
$sth->execute or croak $dbh->errstr;
my $locked = $sth->fetchrow_array;
$sth->finish;
return $locked;
}
# Returns 1 if we can unlock, 0 if we can't, croaks on error.
sub _unlock_node {
my ($self, $node) = @_;
my $dbh = $self->{_dbh};
$node = $dbh->quote($node);
my $sql = "SELECT RELEASE_LOCK($node)";
my $sth = $dbh->prepare($sql);
$sth->execute or croak $dbh->errstr;
my $unlocked = $sth->fetchrow_array;
$sth->finish;
return $unlocked;
}
sub _get_casesensitive_compare_sql {
my ($self, $column) = @_;
return "BINARY $column = ?";
}
1;