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# Copyright (c) 2006, 2007 - OpenSLX GmbH
#
# This program is free software distributed under the GPL version 2.
# See http://openslx.org/COPYING
#
# If you have any feedback please consult http://openslx.org/feedback and
# send your suggestions, praise, or complaints to feedback@openslx.org
#
# General information about OpenSLX can be found at http://openslx.org/
# -----------------------------------------------------------------------------
# CSV.pm
# - provides CSV-specific overrides of the OpenSLX MetaDB API.
# -----------------------------------------------------------------------------
package OpenSLX::MetaDB::CSV;
use strict;
use warnings;
use base qw(OpenSLX::MetaDB::DBI);
################################################################################
### This class provides a MetaDB backend for CSV files (CSV = comma separated
### files).
### - each table will be stored into a CSV file.
### - by default all files will be created inside a 'openslxdata-csv' directory.
################################################################################
use Fcntl qw(:DEFAULT :flock);
use DBD::CSV 0.22;
use OpenSLX::Basics;
################################################################################
### implementation
################################################################################
sub new
{
my $class = shift;
my $self = {};
return bless $self, $class;
}
sub connect ## no critic (ProhibitBuiltinHomonyms)
{
my $self = shift;
my $dbSpec = $openslxConfig{'db-spec'};
if (!defined $dbSpec) {
# build $dbSpec from individual parameters:
my $dbBasepath = "$openslxConfig{'private-path'}/db";
my $dbDatadir = "$openslxConfig{'db-name'}-csv";
my $dbPath = "$dbBasepath/$dbDatadir";
system("mkdir -p $dbPath") unless -e $dbPath;
$dbSpec = "f_dir=$dbPath;csv_eol=\n;";
}
vlog(1, "trying to connect to CSV-database <$dbSpec>");
$self->{'dbh'} =
DBI->connect("dbi:CSV:$dbSpec", undef, undef, {PrintError => 0})
or die _tr("Cannot connect to database '%s' (%s)", $dbSpec, $DBI::errstr);
return;
}
sub quote
{ # DBD::CSV has a buggy quoting mechanism which can't cope with backslashes
# so we reimplement the quoting ourselves...
my $self = shift;
my $val = shift;
$val =~ s[(['])][\\$1]go;
return "'$val'";
}
sub start_transaction
{ # simulate a global transaction by flocking a file:
my $self = shift;
my $dbh = $self->{'dbh'};
my $lockFile = "$dbh->{'f_dir'}/transaction-lock";
sysopen(TRANSFILE, $lockFile, O_RDWR | O_CREAT)
or croak _tr(q[Can't open transaction-file '%s' (%s)], $lockFile, $!);
$self->{"transaction-lock"} = *TRANSFILE;
flock(TRANSFILE, LOCK_EX)
or croak _tr(q[Can't lock transaction-file '%s' (%s)], $lockFile, $!);
return;
}
sub commit_transaction
{ # free transaction-lock
my $self = shift;
if (!defined $self->{"transaction-lock"}) {
croak _tr(q[no open transaction-lock found!]);
}
close($self->{"transaction-lock"});
$self->{"transaction-lock"} = undef;
return 1;
}
sub rollback_transaction
{ # free transaction-lock
my $self = shift;
if (!defined $self->{"transaction-lock"}) {
croak _tr(q[no open transaction-lock found!]);
}
close($self->{"transaction-lock"});
$self->{"transaction-lock"} = undef;
return 1;
}
sub generateNextIdForTable
{ # CSV doesn't provide any mechanism to generate IDs, we provide one
my $self = shift;
my $table = shift;
return 1 unless defined $table;
# fetch the next ID from a table-specific file:
my $dbh = $self->{'dbh'};
my $idFile = "$dbh->{'f_dir'}/id-$table";
sysopen(IDFILE, $idFile, O_RDWR | O_CREAT)
or croak _tr(q[Can't open ID-file '%s' (%s)], $idFile, $!);
flock(IDFILE, LOCK_EX)
or croak _tr(q[Can't lock ID-file '%s' (%s)], $idFile, $!);
my $nextID = <IDFILE>;
if (!$nextID) {
# no ID information available, we protect against users having
# deleted the ID-file by fetching the highest ID from the DB:
#
# N.B.: older versions of DBD::CSV (notably the one that comes with
# SUSE-9.3) do not understand the max() function, so we determine
# the maximum ID manually:
my @IDs =
sort { $b <=> $a } $self->_doSelect("SELECT id FROM $table", 'id');
my $maxID = $IDs[0];
$nextID = 1 + $maxID;
}
seek(IDFILE, 0, 0)
or croak _tr(q[Can't to seek ID-file '%s' (%s)], $idFile, $!);
truncate(IDFILE, 0)
or croak _tr(q[Can't truncate ID-file '%s' (%s)], $idFile, $!);
print IDFILE $nextID + 1
or croak _tr(q[Can't update ID-file '%s' (%s)], $idFile, $!);
close(IDFILE);
return $nextID;
}
sub schemaDeclareTable
{ # explicitly set file name for each table such that it makes
# use of '.csv'-extension
my $self = shift;
my $table = shift;
my $dbh = $self->{'dbh'};
$dbh->{'csv_tables'}->{"$table"} = {'file' => "${table}.csv"};
return;
}
sub schemaRenameTable
{ # renames corresponding id-file after renaming the table
my $self = shift;
my $oldTable = shift;
my $newTable = shift;
$self->schemaDeclareTable($newTable);
$self->SUPER::schemaRenameTable($oldTable, $newTable, @_);
my $dbh = $self->{'dbh'};
rename "$dbh->{'f_dir'}/id-$oldTable", "$dbh->{'f_dir'}/id-$newTable";
return;
}
sub schemaDropTable
{ # removes corresponding id-file after dropping the table
my $self = shift;
my $table = shift;
$self->SUPER::schemaDropTable($table, @_);
my $dbh = $self->{'dbh'};
unlink "$dbh->{'f_dir'}/id-$table";
return;
}
1;
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