pureperl.pm

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

        $h->{$key} = $value;
        if ($value) {
            my $fbav = DBD::_::st::dbih_setup_fbav($h);
            @$fbav = (undef) x $value if @$fbav != $value;
        }
	return 1;
    }
    elsif (!$is_valid_attribute{$key} && $key =~ /^[A-Z]/ && !exists $h->{$key}) {
       Carp::carp(sprintf "Can't set %s->{%s}: unrecognised attribute or invalid value %s",
	    $h,$key,$value);
    }
    $h->{$key} = $is_flag_attribute{$key} ? !!$value : $value;
    return 1;
}
sub err    { return shift->{err}    }
sub errstr { return shift->{errstr} }
sub state  { return shift->{state}  }
sub set_err {
    my ($h, $errnum,$msg,$state, $method, $rv) = @_;
    $h = tied(%$h) || $h;

    if (my $hss = $h->{HandleSetErr}) {
	return if $hss->($h, $errnum, $msg, $state, $method);
    }

    if (!defined $errnum) {
	$h->{err}    = $DBI::err    = undef;
	$h->{errstr} = $DBI::errstr = undef;
	$h->{state}  = $DBI::state  = '';
        return;
    }

    if ($h->{errstr}) {
	$h->{errstr} .= sprintf " [err was %s now %s]", $h->{err}, $errnum
		if $h->{err} && $errnum && $h->{err} ne $errnum;
	$h->{errstr} .= sprintf " [state was %s now %s]", $h->{state}, $state
		if $h->{state} and $h->{state} ne "S1000" && $state && $h->{state} ne $state;
	$h->{errstr} .= "\n$msg" if $h->{errstr} ne $msg;
	$DBI::errstr = $h->{errstr};
    }
    else {
	$h->{errstr} = $DBI::errstr = $msg;
    }

    # assign if higher priority: err > "0" > "" > undef
    my $err_changed;
    if ($errnum			# new error: so assign
	or !defined $h->{err}	# no existing warn/info: so assign
           # new warn ("0" len 1) > info ("" len 0): so assign
	or defined $errnum && length($errnum) > length($h->{err})
    ) {
        $h->{err} = $DBI::err = $errnum;
	++$h->{ErrCount} if $errnum;
	++$err_changed;
    }

    if ($err_changed) {
	$state ||= "S1000" if $DBI::err;
	$h->{state} = $DBI::state = ($state eq "00000") ? "" : $state
	    if $state;
    }

    if (my $p = $h->{Database}) { # just sth->dbh, not dbh->drh (see ::db::DESTROY)
	$p->{err}    = $DBI::err;
	$p->{errstr} = $DBI::errstr;
	$p->{state}  = $DBI::state;
    }

    $h->{'dbi_pp_last_method'} = $method;
    return $rv; # usually undef
}
sub trace_msg {
    my ($h, $msg, $minlevel)=@_;
    $minlevel = 1 unless defined $minlevel;
    return unless $minlevel <= ($DBI::dbi_debug & 0xF);
    print $DBI::tfh $msg;
    return 1;
}
sub private_data {
    warn "private_data @_";
}
sub take_imp_data {
    my $dbh = shift;
    # A reasonable default implementation based on the one in DBI.xs.
    # Typically a pure-perl driver would have their own take_imp_data method
    # that would delete all but the essential items in the hash before einding with:
    #      return $dbh->SUPER::take_imp_data();
    # Of course it's useless if the driver doesn't also implement support for
    # the dbi_imp_data attribute to the connect() method.
    require Storable;
    croak("Can't take_imp_data from handle that's not Active")
        unless $dbh->{Active};
    for my $sth (@{ $dbh->{ChildHandles} || [] }) {
        next unless $sth;
        $sth->finish if $sth->{Active};
        bless $sth, 'DBI::zombie';
    }
    delete $dbh->{$_} for (keys %is_valid_attribute);
    delete $dbh->{$_} for grep { m/^dbi_/ } keys %$dbh;
    # warn "@{[ %$dbh ]}";
    local $Storable::forgive_me = 1; # in case there are some CODE refs
    my $imp_data = Storable::freeze($dbh);
    # XXX um, should probably untie here - need to check dispatch behaviour
    return $imp_data;
}
sub rows {
    return -1; # always returns -1 here, see DBD::_::st::rows below
}
sub DESTROY {
}

package
	DBD::_::db;

sub connected {
}


package
	DBD::_::st;

sub fetchrow_arrayref	{
    my $h = shift;
    # if we're here then driver hasn't implemented fetch/fetchrow_arrayref
    # so we assume they've implemented fetchrow_array and call that instead
    my @row = $h->fetchrow_array or return;
    return $h->_set_fbav(\@row);
}
# twice to avoid typo warning
*fetch = \&fetchrow_arrayref;  *fetch = \&fetchrow_arrayref;

sub fetchrow_array	{
    my $h = shift;
    # if we're here then driver hasn't implemented fetchrow_array
    # so we assume they've implemented fetch/fetchrow_arrayref
    my $row = $h->fetch or return;
    return @$row;
}
*fetchrow = \&fetchrow_array; *fetchrow = \&fetchrow_array;

sub fetchrow_hashref {
    my $h         = shift;
    my $row       = $h->fetch or return;
    my $FetchCase = shift;
    my $FetchHashKeyName = $FetchCase || $h->{'FetchHashKeyName'} || 'NAME';
    my $FetchHashKeys    = $h->FETCH($FetchHashKeyName);
    my %rowhash;
    @rowhash{ @$FetchHashKeys } = @$row;
    return \%rowhash;
}
sub dbih_setup_fbav {
    my $h = shift;
    return $h->{'_fbav'} || do {
        $DBI::rows = $h->{'_rows'} = 0;
        my $fields = $h->{'NUM_OF_FIELDS'}
                  or DBI::croak("NUM_OF_FIELDS not set");
        my @row = (undef) x $fields;
        \@row;
    };
}
sub _get_fbav {
    my $h = shift;
    my $av = $h->{'_fbav'} ||= dbih_setup_fbav($h);
    $DBI::rows = ++$h->{'_rows'};
    return $av;
}
sub _set_fbav {
    my $h = shift;
    my $fbav = $h->{'_fbav'};
    if ($fbav) {
	$DBI::rows = ++$h->{'_rows'};
    }
    else {
	$fbav = $h->_get_fbav;
    }
    my $row = shift;
    if (my $bc = $h->{'_bound_cols'}) {
        for my $i (0..@$row-1) {
            my $bound = $bc->[$i];
            $fbav->[$i] = ($bound) ? ($$bound = $row->[$i]) : $row->[$i];
        }
    }
    else {
        @$fbav = @$row;
    }
    return $fbav;
}
sub bind_col {
    my ($h, $col, $value_ref,$from_bind_columns) = @_;
    my $fbav = $h->{'_fbav'} ||= dbih_setup_fbav($h); # from _get_fbav()
    my $num_of_fields = @$fbav;
    DBI::croak("bind_col: column $col is not a valid column (1..$num_of_fields)")
        if $col < 1 or $col > $num_of_fields;
    return 1 if not defined $value_ref; # ie caller is just trying to set TYPE
    DBI::croak("bind_col($col,$value_ref) needs a reference to a scalar")
	unless ref $value_ref eq 'SCALAR';
    $h->{'_bound_cols'}->[$col-1] = $value_ref;
    return 1;
}
sub finish {
    my $h = shift;
    $h->{'_fbav'} = undef;
    $h->{'Active'} = 0;
    return 1;
}
sub rows {
    my $h = shift;
    my $rows = $h->{'_rows'};
    return -1 unless defined $rows;
    return $rows;
}

1;
__END__

=pod

=head1 NAME

DBI::PurePerl -- a DBI emulation using pure perl (no C/XS compilation required)

=head1 SYNOPSIS

 BEGIN { $ENV{DBI_PUREPERL} = 2 }
 use DBI;

=head1 DESCRIPTION

This is a pure perl emulation of the DBI internals.  In almost all
cases you will be better off using standard DBI since the portions
of the standard version written in C make it *much* faster.

However, if you are in a situation where it isn't possible to install
a compiled version of standard DBI, and you're using pure-perl DBD
drivers, then this module allows you to use most common features
of DBI without needing any changes in your scripts.

=head1 EXPERIMENTAL STATUS

DBI::PurePerl is new so please treat it as experimental pending
more extensive testing.  So far it has passed all tests with DBD::CSV,
DBD::AnyData, DBD::XBase, DBD::Sprite, DBD::mysqlPP.  Please send
bug reports to Jeff Zucker at <[e-mail]> with a cc to
<[e-mail]>.

=head1 USAGE

The usage is the same as for standard DBI with the exception
that you need to set the enviornment variable DBI_PUREPERL if
you want to use the PurePerl version.

 DBI_PUREPERL == 0 (the default) Always use compiled DBI, die
                   if it isn't properly compiled & installed

 DBI_PUREPERL == 1 Use compiled DBI if it is properly compiled
                   & installed, otherwise use PurePerl

 DBI_PUREPERL == 2 Always use PurePerl

You may set the enviornment variable in your shell (e.g. with
set or setenv or export, etc) or else set it in your script like
this:

 BEGIN { $ENV{DBI_PUREPERL}=2 }

before you C<use DBI;>.

=head1 INSTALLATION

In most situations simply install DBI (see the DBI pod for details).

In the situation in which you can not install DBI itself, you
may manually copy DBI.pm and PurePerl.pm into the appropriate
directories.

For example:

 cp DBI.pm      /usr/jdoe/mylibs/.
 cp PurePerl.pm /usr/jdoe/mylibs/DBI/.

Then add this to the top of scripts:

 BEGIN {
   $ENV{DBI_PUREPERL} = 1;	# or =2
   unshift @INC, '/usr/jdoe/mylibs';
 }

(Or should we perhaps patch Makefile.PL so that if DBI_PUREPERL
is set to 2 prior to make, the normal compile process is skipped
and the files are installed automatically?)

=head1 DIFFERENCES BETWEEN DBI AND DBI::PurePerl

=head2 Attributes

Boolean attributes still return boolean values but the actual values
used may be different, i.e., 0 or undef instead of an empty string.

Some handle attributes are either not supported or have very limited
functionality:

  ActiveKids
  InactiveDestroy
  Kids
  Taint
  TaintIn
  TaintOut

(and probably others)

=head2 Tracing

Trace functionality is more limited and the code to handle tracing is
only embeded into DBI:PurePerl if the DBI_TRACE environment variable
is defined.  To enable total tracing you can set the DBI_TRACE
environment variable as usual.  But to enable individual handle
tracing using the trace() method you also need to set the DBI_TRACE
environment variable, but set it to 0.

=head2 Parameter Usage Checking

The DBI does some basic parameter count checking on method calls.
DBI::PurePerl doesn't.

=head2 Speed

DBI::PurePerl is slower. Although, with some drivers in some
contexts this may not be very significant for you.

By way of example... the test.pl script in the DBI source
distribution has a simple benchmark that just does:

    my $null_dbh = DBI->connect('dbi:NullP:','','');
    my $i = 10_000;
    $null_dbh->prepare('') while $i--;

In other words just prepares a statement, creating and destroying
a statement handle, over and over again.  Using the real DBI this
runs at ~4550 handles per second whereas DBI::PurePerl manages
~2800 per second on the same machine (not too bad really).

=head2 May not fully support hash()

If you want to use type 1 hash, i.e., C<hash($string,1)> with
DBI::PurePerl, you'll need version 1.56 or higher of Math::BigInt
(available on CPAN).

=head2 Doesn't support preparse()

The DBI->preparse() method isn't supported in DBI::PurePerl.

=head2 Doesn't support DBD::Proxy

There's a subtle problem somewhere I've not been able to identify.
DBI::ProxyServer seem to work fine with DBI::PurePerl but DBD::Proxy
does not work 100% (which is sad because that would be far more useful :)
Try re-enabling t/80proxy.t for DBI::PurePerl to see if the problem
that remains will affect you're usage.

=head2 Others

  can() - doesn't have any special behaviour

Please let us know if you find any other differences between DBI
and DBI::PurePerl.

=head1 AUTHORS

Tim Bunce and Jeff Zucker.

Tim provided the direction and basis for the code.  The original
idea for the module and most of the brute force porting from C to
Perl was by Jeff. Tim then reworked some core parts to boost the
performance and accuracy of the emulation. Thanks also to Randal
Schwartz and John Tobey for patches.

=head1 COPYRIGHT

Copyright (c) 2002  Tim Bunce  Ireland.

See COPYRIGHT section in DBI.pm for usage and distribution rights.

=cut