[webpac] / index_DBI_cache.pm

#
# this file implements index functions using DBI
# and huge amounts of memory for cache speedup
#
# this version doesn't support ident (which sould be location in
# library). But, that functionality is not used anyway...
#

package index_DBI;
use strict qw(vars);
use vars qw($Count);
use HTML::Entities;

use DBI;

my %Table;      # index tables which where visited in this run
my %sth_cache;  # cache prepared statements

# cache var
my $c_table;
my $c_count;

# bench time
my $bench_time = time();

sub bench {
        my $self = shift;
        my $msg = shift;

        print STDERR "last operation took ",time()-$bench_time," seconds...\n";
        $bench_time=time();
        print STDERR "$msg\n";
}

sub new {
        my $class = shift;
        my $self = {};
        bless($self, $class);

        my $dbd = shift || die "need dbi_dbd= in [global] section of configuration file";
        my $dsn = shift || die "need dbi_dsn= in [global] section of configuration file";
        my $user = shift || die "need dbi_user= in [global] section of configuration file";
        my $passwd = shift || die "need dbi_passwd= in [global] section of configuration file";

        $self->{dbh} = DBI->connect("DBI:$dbd:$dsn",$user,$passwd) || die $DBI::errstr;
        $Count++;

        $self->bench("connected to $dbd as $user");

        return $self;
}

sub delete_and_create {
        my $self = shift;

        my $field = shift;

#print "#### delete_and_create($field)\n";

        my $sql = "select count(*) from $field";
        my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
# FIX: this is not a good way to check if table exists!
        if ($sth->execute() && $sth->fetchrow_hashref) {
                my $sql = "drop table $field";
                my $sth = $self->{dbh}->do($sql) || die "SQL: $sql ".$self->{dbh}->errstr();
        }
        $sql = "create table $field (
                        item varchar(255),
                        count int,
                        ord int,
                        primary key (item)
                )";

        $sth = $self->{dbh}->do($sql) || warn "SQL: $sql ".$self->{dbh}->errstr();
}

sub insert {
        my $self = shift;

        my $field = shift;
        my $index_data = shift || print STDERR "\$index->insert($field,NULL,...)";
        my $ident = shift || '';        # e.g. library id

        if (! $index_data) {
                print STDERR "\$index->insert() -- no value to insert\n";
                return;
        }

        $Table{$field}++;

        #$sth_cache{$field."select"}->execute($index_data) || die "cache: $field select; ".$self->{dbh}->errstr();

        # XXX for some strange reason, it seems that some entries in my
        # database produce strings which start with null byte. I suspect
        # this to be bug in OpenIsis 0.9.0.
        # This should fix it..
        $index_data =~ s/^[^\w]+//;
        $index_data = substr($index_data,0,255);

        my $uc = uc($index_data);
        if (! $c_table->{$field}->{$uc}) {
#print stderr "in index: $index_data\n";
                $c_table->{$field}->{$uc} = $index_data;
                $c_count->{$field}->{$uc} = 1;
        } else {
                $c_count->{$field}->{$uc}++;
        }
}

sub check {
        my $self = shift;

        my $field = shift;

        my $sql = "select count(*) from $field";

        my $sth = $self->{dbh}->prepare($sql) || die $self->{dbh}->errstr();
        $sth->execute() || die "sql: $sql; ".$self->{dbh}->errstr();

        my ($total) = $sth->fetchrow_array();

        return $total;
}


sub fetch {
        my $self = shift;

        my $field = shift;
        my $what = shift || 'item';     # 'item,ident'
        my $where = shift;

        my $from_ord = shift || 0;
        my $rows = shift || 10;

        my @sql_args;

        my $sql = "select $what,ord from $field";

        if ($where) {
                my $sql2 = "select ord from $field where upper($what) like upper(?)||'%'";
                my $sth = $self->{dbh}->prepare($sql2) || die "sql2: $sql2; ".$self->{dbh}->errstr();

                $sth->execute($where) || die "sql2: $sql2; ".$self->{dbh}->errstr();
                if (my $row = $sth->fetchrow_hashref) {
                        $from_ord += $row->{ord} - 1;
                } else {
                        # if no match is found when searching from beginning
                        # of word in index, try substring match anywhere
                        $sql2 = "select ord from $field where upper($what) like '%'||upper(?)||'%'";
                        $sth = $self->{dbh}->prepare($sql2) || die "sql2: $sql2; ".$self->{dbh}->errstr();
                        $sth->execute($where) || die "sql2: $sql2; ".$self->{dbh}->errstr();
                        if (my $row = $sth->fetchrow_hashref) {
                                $from_ord += $row->{ord} - 1;
                        }
                }
        }
        $sql .= " order by ord limit $rows offset $from_ord";

        my $sth = $self->{dbh}->prepare($sql) || die "prepare: $sql; ".$self->{dbh}->errstr();
        $sth->execute() || die "execute: $sql; ".$self->{dbh}->errstr();
        my @arr;
        while (my $row = $sth->fetchrow_hashref) {
                $row->{item} = HTML::Entities::encode($row->{item},'<>&"');
                push @arr,$row;
        }
        return @arr;
}

sub close {
        my $self = shift;

        return if (! $self->{dbh});

        foreach my $table (keys %Table) {
                $self->bench("Crating table $table");
                $self->delete_and_create($table);

                $self->{dbh}->begin_work || die $self->{dbh}->errstr();

                $self->bench("Sorting ".$Table{$table}." items in $table");
                my @keys = sort keys %{$c_table->{$table}};

                $self->bench("Dumping data into $table");
                my $sql = "insert into $table (ord,item,count) values (?,?,?)";
                my $sth = $self->{dbh}->prepare($sql) || die "sql: $sql; ".$self->{dbh}->errstr();

                my $ord = 0;
                foreach my $key (@keys) {
                        $sth->execute(++$ord,
                                $c_table->{$table}->{$key},
                                $c_count->{$table}->{$key}
                        );
                }

                $self->{dbh}->commit || die $self->{dbh}->errstr();
        }
        $self->bench("disconnecting from database");

        $self->{dbh}->disconnect;
        undef $self->{dbh};
}

END {
        $Count--;
        print STDERR "index_DBI fatal error: \$index->close() not called... $Count references left!\n" if ($Count > 0);
        # FIX: debug output
#       print STDERR "usage\ttable\n";
#       foreach (keys %Table) {
#               print STDERR $Table{$_},"\t$_\n";
#       }
}

1;