}
    return $yaml_module;
}

# CPAN::_yaml_loadfile
sub _yaml_loadfile {
    my($self,$local_file) = @_;
    return +[] unless -s $local_file;
    my $yaml_module = _yaml_module;
    if ($CPAN::META->has_inst($yaml_module)) {
        # temporarly enable yaml code deserialisation
        no strict 'refs';
        # 5.6.2 could not do the local() with the reference
        # so we do it manually instead
        my $old_loadcode = ${"$yaml_module\::LoadCode"};
        ${ "$yaml_module\::LoadCode" } = $CPAN::Config->{yaml_load_code} || 0;

        my ($code, @yaml);
        if ($code = UNIVERSAL::can($yaml_module, "LoadFile")) {
            eval { @yaml = $code->($local_file); };
            if ($@) {
                # this shall not be done by the frontend
                die CPAN::Exception::yaml_process_error->new($yaml_module,$local_file,"parse",$@);
            }
        } elsif ($code = UNIVERSAL::can($yaml_module, "Load")) {
            local *FH;
            open FH, $local_file or die "Could not open '$local_file': $!";
            local $/;
            my $ystream = <FH>;
            eval { @yaml = $code->($ystream); };
            if ($@) {
                # this shall not be done by the frontend
                die CPAN::Exception::yaml_process_error->new($yaml_module,$local_file,"parse",$@);
            }
        }
        ${"$yaml_module\::LoadCode"} = $old_loadcode;
        return \@yaml;
    } else {
        # this shall not be done by the frontend
        die CPAN::Exception::yaml_not_installed->new($yaml_module, $local_file, "parse");
    }
    return +[];
}

# CPAN::_yaml_dumpfile
sub _yaml_dumpfile {
    my($self,$local_file,@what) = @_;
    my $yaml_module = _yaml_module;
    if ($CPAN::META->has_inst($yaml_module)) {
        my $code;
        if (UNIVERSAL::isa($local_file, "FileHandle")) {
            $code = UNIVERSAL::can($yaml_module, "Dump");
            eval { print $local_file $code->(@what) };
        } elsif ($code = UNIVERSAL::can($yaml_module, "DumpFile")) {
            eval { $code->($local_file,@what); };
        } elsif ($code = UNIVERSAL::can($yaml_module, "Dump")) {
            local *FH;
            open FH, ">$local_file" or die "Could not open '$local_file': $!";
            print FH $code->(@what);
        }
        if ($@) {
            die CPAN::Exception::yaml_process_error->new($yaml_module,$local_file,"dump",$@);
        }
    } else {
        if (UNIVERSAL::isa($local_file, "FileHandle")) {
            # I think this case does not justify a warning at all
        } else {
            die CPAN::Exception::yaml_not_installed->new($yaml_module, $local_file, "dump");
        }
    }
}

sub _init_sqlite () {
    unless ($CPAN::META->has_inst("CPAN::SQLite")) {
        $CPAN::Frontend->mywarn(qq{CPAN::SQLite not installed, trying to work without\n})
            unless $Have_warned->{"CPAN::SQLite"}++;
        return;
    }
    require CPAN::SQLite::META; # not needed since CVS version of 2006-12-17
    $CPAN::SQLite ||= CPAN::SQLite::META->new($CPAN::META);
}

{
    my $negative_cache = {};
    sub _sqlite_running {
        if ($negative_cache->{time} && time < $negative_cache->{time} + 60) {
            # need to cache the result, otherwise too slow
            return $negative_cache->{fact};
        } else {
            $negative_cache = {}; # reset
        }
        my $ret = $CPAN::Config->{use_sqlite} && ($CPAN::SQLite || _init_sqlite());
        return $ret if $ret; # fast anyway
        $negative_cache->{time} = time;
        return $negative_cache->{fact} = $ret;
    }
}

package CPAN::CacheMgr;
use strict;