File Coverage

blib/lib/DBI/PurePerl.pm

Criterion	Covered	Total	%
statement	629	657	95.7
branch	248	290	85.5
condition	88	119	73.9
subroutine	125	134	93.2
pod	5	10	50.0
total	1095	1210	90.5

########################################################################
package		# hide from PAUSE
	DBI;
# vim: ts=8:sw=4
########################################################################
#
# Copyright (c) 2002,2003  Tim Bunce  Ireland.
#
# See COPYRIGHT section in DBI.pm for usage and distribution rights.
#
########################################################################
#
# Please send patches and bug reports to
#
# Jeff Zucker   with cc to
#
########################################################################

use strict;
use Carp;
require Symbol;

require utf8;
*utf8::is_utf8 = sub { # hack for perl 5.6
    require bytes;
    return unless defined $_[0];
    return !(length($_[0]) == bytes::length($_[0]))
} unless defined &utf8::is_utf8;

$DBI::PurePerl = $ENV{DBI_PUREPERL} || 1;
$DBI::PurePerl::VERSION = "2.014286";

$DBI::neat_maxlen ||= 400;

$DBI::tfh = Symbol::gensym();
open $DBI::tfh, ">&STDERR" or warn "Can't dup STDERR: $!";
select( (select($DBI::tfh), $| = 1)[0] );  # autoflush

# check for weaken support, used by ChildHandles
my $HAS_WEAKEN = eval {
    require Scalar::Util;
    # this will croak() if this Scalar::Util doesn't have a working weaken().
    Scalar::Util::weaken( my $test = [] );
    1;
};

%DBI::last_method_except = map { $_=>1 } qw(DESTROY _set_fbav set_err);

use constant SQL_ALL_TYPES => 0;
use constant SQL_ARRAY => 50;
use constant SQL_ARRAY_LOCATOR => 51;
use constant SQL_BIGINT => (-5);
use constant SQL_BINARY => (-2);
use constant SQL_BIT => (-7);
use constant SQL_BLOB => 30;
use constant SQL_BLOB_LOCATOR => 31;
use constant SQL_BOOLEAN => 16;
use constant SQL_CHAR => 1;
use constant SQL_CLOB => 40;
use constant SQL_CLOB_LOCATOR => 41;
use constant SQL_DATE => 9;
use constant SQL_DATETIME => 9;
use constant SQL_DECIMAL => 3;
use constant SQL_DOUBLE => 8;
use constant SQL_FLOAT => 6;
use constant SQL_GUID => (-11);
use constant SQL_INTEGER => 4;
use constant SQL_INTERVAL => 10;
use constant SQL_INTERVAL_DAY => 103;
use constant SQL_INTERVAL_DAY_TO_HOUR => 108;
use constant SQL_INTERVAL_DAY_TO_MINUTE => 109;
use constant SQL_INTERVAL_DAY_TO_SECOND => 110;
use constant SQL_INTERVAL_HOUR => 104;
use constant SQL_INTERVAL_HOUR_TO_MINUTE => 111;
use constant SQL_INTERVAL_HOUR_TO_SECOND => 112;
use constant SQL_INTERVAL_MINUTE => 105;
use constant SQL_INTERVAL_MINUTE_TO_SECOND => 113;
use constant SQL_INTERVAL_MONTH => 102;
use constant SQL_INTERVAL_SECOND => 106;
use constant SQL_INTERVAL_YEAR => 101;
use constant SQL_INTERVAL_YEAR_TO_MONTH => 107;
use constant SQL_LONGVARBINARY => (-4);
use constant SQL_LONGVARCHAR => (-1);
use constant SQL_MULTISET => 55;
use constant SQL_MULTISET_LOCATOR => 56;
use constant SQL_NUMERIC => 2;
use constant SQL_REAL => 7;
use constant SQL_REF => 20;
use constant SQL_ROW => 19;
use constant SQL_SMALLINT => 5;
use constant SQL_TIME => 10;
use constant SQL_TIMESTAMP => 11;
use constant SQL_TINYINT => (-6);
use constant SQL_TYPE_DATE => 91;
use constant SQL_TYPE_TIME => 92;
use constant SQL_TYPE_TIMESTAMP => 93;
use constant SQL_TYPE_TIMESTAMP_WITH_TIMEZONE => 95;
use constant SQL_TYPE_TIME_WITH_TIMEZONE => 94;
use constant SQL_UDT => 17;
use constant SQL_UDT_LOCATOR => 18;
use constant SQL_UNKNOWN_TYPE => 0;
use constant SQL_VARBINARY => (-3);
use constant SQL_VARCHAR => 12;
use constant SQL_WCHAR => (-8);
use constant SQL_WLONGVARCHAR => (-10);
use constant SQL_WVARCHAR => (-9);

# for Cursor types
use constant SQL_CURSOR_FORWARD_ONLY  => 0;
use constant SQL_CURSOR_KEYSET_DRIVEN => 1;
use constant SQL_CURSOR_DYNAMIC       => 2;
use constant SQL_CURSOR_STATIC        => 3;
use constant SQL_CURSOR_TYPE_DEFAULT  => SQL_CURSOR_FORWARD_ONLY;

use constant IMA_HAS_USAGE	=> 0x0001; #/* check parameter usage	*/
use constant IMA_FUNC_REDIRECT	=> 0x0002; #/* is $h->func(..., "method")*/
use constant IMA_KEEP_ERR	=> 0x0004; #/* don't reset err & errstr	*/
use constant IMA_KEEP_ERR_SUB	=> 0x0008; #/*  '' if in nested call */
use constant IMA_NO_TAINT_IN   	=> 0x0010; #/* don't check for tainted args*/
use constant IMA_NO_TAINT_OUT   => 0x0020; #/* don't taint results	*/
use constant IMA_COPY_UP_STMT   => 0x0040; #/* copy sth Statement to dbh */
use constant IMA_END_WORK	=> 0x0080; #/* set on commit & rollback	*/
use constant IMA_STUB		=> 0x0100; #/* do nothing eg $dbh->connected */
use constant IMA_CLEAR_STMT     => 0x0200; #/* clear Statement before call  */
use constant IMA_UNRELATED_TO_STMT=> 0x0400; #/* profile as empty Statement   */
use constant IMA_NOT_FOUND_OKAY	=> 0x0800; #/* not error if not found */
use constant IMA_EXECUTE	=> 0x1000; #/* do/execute: DBIcf_Executed   */
use constant IMA_SHOW_ERR_STMT  => 0x2000; #/* dbh meth relates to Statement*/
use constant IMA_HIDE_ERR_PARAMVALUES => 0x4000; #/* ParamValues are not relevant */
use constant IMA_IS_FACTORY     => 0x8000; #/* new h ie connect & prepare */
use constant IMA_CLEAR_CACHED_KIDS    => 0x10000; #/* clear CachedKids before call */

use constant DBIstcf_STRICT           => 0x0001;
use constant DBIstcf_DISCARD_STRING   => 0x0002;

my %is_flag_attribute = map {$_ =>1 } qw(
	Active
	AutoCommit
	ChopBlanks
	CompatMode
	Executed
	Taint
	TaintIn
	TaintOut
	InactiveDestroy
	AutoInactiveDestroy
	LongTruncOk
	MultiThread
	PrintError
	PrintWarn
	RaiseError
	ShowErrorStatement
	Warn
);
my %is_valid_attribute = map {$_ =>1 } (keys %is_flag_attribute, qw(
	ActiveKids
	Attribution
	BegunWork
	CachedKids
        Callbacks
	ChildHandles
	CursorName
	Database
	DebugDispatch
	Driver
        Err
        Errstr
	ErrCount
	FetchHashKeyName
	HandleError
	HandleSetErr
	ImplementorClass
	Kids
	LongReadLen
	NAME NAME_uc NAME_lc NAME_uc_hash NAME_lc_hash
	NULLABLE
	NUM_OF_FIELDS
	NUM_OF_PARAMS
	Name
	PRECISION
	ParamValues
	Profile
	Provider
        ReadOnly
	RootClass
	RowCacheSize
	RowsInCache
	SCALE
        State
	Statement
	TYPE
        Type
	TraceLevel
	Username
	Version
));

sub valid_attribute {
    my $attr = shift;
    return 1 if $is_valid_attribute{$attr};
    return 1 if $attr =~ m/^[a-z]/; # starts with lowercase letter
    return 0
}

my $initial_setup;
sub initial_setup {
    $initial_setup = 1;
    print $DBI::tfh  __FILE__ . " version " . $DBI::PurePerl::VERSION . "\n"
	if $DBI::dbi_debug & 0xF;
    untie $DBI::err;
    untie $DBI::errstr;
    untie $DBI::state;
    untie $DBI::rows;
    #tie $DBI::lasth,  'DBI::var', '!lasth';  # special case: return boolean
}

sub  _install_method {
    my ( $caller, $method, $from, $param_hash ) = @_;
    initial_setup() unless $initial_setup;

    my ($class, $method_name) = $method =~ /^[^:]+::(.+)::(.+)$/;
    my $bitmask = $param_hash->{'O'} || 0;
    my @pre_call_frag;

    return if $method_name eq 'can';

    push @pre_call_frag, q{
        # ignore DESTROY for outer handle (DESTROY for inner likely to follow soon)
	return if $h_inner;
        # handle AutoInactiveDestroy and InactiveDestroy
        $h->{InactiveDestroy} = 1
            if $h->{AutoInactiveDestroy} and $$ != $h->{dbi_pp_pid};
        $h->{Active} = 0
            if $h->{InactiveDestroy};
	# copy err/errstr/state up to driver so $DBI::err etc still work
	if ($h->{err} and my $drh = $h->{Driver}) {
	    $drh->{$_} = $h->{$_} for ('err','errstr','state');
	}
    } if $method_name eq 'DESTROY';

    push @pre_call_frag, q{
	return $h->{$_[0]} if exists $h->{$_[0]};
    } if $method_name eq 'FETCH' && !exists $ENV{DBI_TRACE}; # XXX ?

    push @pre_call_frag, "return;"
	if IMA_STUB & $bitmask;

    push @pre_call_frag, q{
	$method_name = pop @_;
    } if IMA_FUNC_REDIRECT & $bitmask;

    push @pre_call_frag, q{
	my $parent_dbh = $h->{Database};
    } if (IMA_COPY_UP_STMT|IMA_EXECUTE) & $bitmask;

    push @pre_call_frag, q{
	warn "No Database set for $h on $method_name!" unless $parent_dbh; # eg proxy problems
	$parent_dbh->{Statement} = $h->{Statement} if $parent_dbh;
    } if IMA_COPY_UP_STMT & $bitmask;

    push @pre_call_frag, q{
	$h->{Executed} = 1;
	$parent_dbh->{Executed} = 1 if $parent_dbh;
    } if IMA_EXECUTE & $bitmask;

    push @pre_call_frag, q{
	%{ $h->{CachedKids} } = () if $h->{CachedKids};
    } if IMA_CLEAR_CACHED_KIDS & $bitmask;

    if (IMA_KEEP_ERR & $bitmask) {
	push @pre_call_frag, q{
	    my $keep_error = DBI::_err_hash($h);
	};
    }
    else {
	my $ke_init = (IMA_KEEP_ERR_SUB & $bitmask)
		? q{= ($h->{dbi_pp_parent}->{dbi_pp_call_depth} && DBI::_err_hash($h)) }
		: "";
	push @pre_call_frag, qq{
	    my \$keep_error $ke_init;
	};
	my $clear_error_code = q{
	    #warn "$method_name cleared err";
	    $h->{err}    = $DBI::err    = undef;
	    $h->{errstr} = $DBI::errstr = undef;
	    $h->{state}  = $DBI::state  = '';
	};
	$clear_error_code = q{
	    printf $DBI::tfh "    !! %s: %s CLEARED by call to }.$method_name.q{ method\n".
		    $h->{err}, $h->{err}
		if defined $h->{err} && $DBI::dbi_debug & 0xF;
	}. $clear_error_code
	    if exists $ENV{DBI_TRACE};
	push @pre_call_frag, ($ke_init)
		? qq{ unless (\$keep_error) { $clear_error_code }}
		: $clear_error_code
	    unless $method_name eq 'set_err';
    }

    push @pre_call_frag, q{
	my $ErrCount = $h->{ErrCount};
    };

    push @pre_call_frag, q{
        if (($DBI::dbi_debug & 0xF) >= 2) {
	    local $^W;
	    my $args = join " ", map { DBI::neat($_) } ($h, @_);
	    printf $DBI::tfh "    > $method_name in $imp ($args) [$@]\n";
	}
    } if exists $ENV{DBI_TRACE};	# note use of 'exists'

    push @pre_call_frag, q{
        $h->{'dbi_pp_last_method'} = $method_name;
    } unless exists $DBI::last_method_except{$method_name};

    # --- post method call code fragments ---
    my @post_call_frag;

    push @post_call_frag, q{
        if (my $trace_level = ($DBI::dbi_debug & 0xF)) {
	    if ($h->{err}) {
		printf $DBI::tfh "    !! ERROR: %s %s\n", $h->{err}, $h->{errstr};
	    }
	    my $ret = join " ", map { DBI::neat($_) } @ret;
	    my $msg = "    < $method_name= $ret";
	    $msg = ($trace_level >= 2) ? Carp::shortmess($msg) : "$msg\n";
	    print $DBI::tfh $msg;
	}
    } if exists $ENV{DBI_TRACE}; # note use of exists

    push @post_call_frag, q{
	$h->{Executed} = 0;
	if ($h->{BegunWork}) {
	    $h->{BegunWork}  = 0;
	    $h->{AutoCommit} = 1;
	}
    } if IMA_END_WORK & $bitmask;

    push @post_call_frag, q{
        if ( ref $ret[0] and
            UNIVERSAL::isa($ret[0], 'DBI::_::common') and
            defined( (my $h_new = tied(%{$ret[0]})||$ret[0])->{err} )
        ) {
            # copy up info/warn to drh so PrintWarn on connect is triggered
            $h->set_err($h_new->{err}, $h_new->{errstr}, $h_new->{state})
        }
    } if IMA_IS_FACTORY & $bitmask;

    push @post_call_frag, q{
        if ($keep_error) {
            $keep_error = 0
                if $h->{ErrCount} > $ErrCount
                or DBI::_err_hash($h) ne $keep_error;
        }

	$DBI::err    = $h->{err};
	$DBI::errstr = $h->{errstr};
	$DBI::state  = $h->{state};

        if ( !$keep_error
	&& defined(my $err = $h->{err})
	&& ($call_depth <= 1 && !$h->{dbi_pp_parent}{dbi_pp_call_depth})
	) {

	    my($pe,$pw,$re,$he) = @{$h}{qw(PrintError PrintWarn RaiseError HandleError)};
	    my $msg;

	    if ($err && ($pe || $re || $he)	# error
	    or (!$err && length($err) && $pw)	# warning
	    ) {
		my $last = ($DBI::last_method_except{$method_name})
		    ? ($h->{'dbi_pp_last_method'}||$method_name) : $method_name;
		my $errstr = $h->{errstr} || $DBI::errstr || $err || '';
		my $msg = sprintf "%s %s %s: %s", $imp, $last,
			($err eq "0") ? "warning" : "failed", $errstr;

		if ($h->{'ShowErrorStatement'} and my $Statement = $h->{Statement}) {
		    $msg .= ' [for Statement "' . $Statement;
		    if (my $ParamValues = $h->FETCH('ParamValues')) {
			$msg .= '" with ParamValues: ';
			$msg .= DBI::_concat_hash_sorted($ParamValues, "=", ", ", 1, undef);
                        $msg .= "]";
		    }
                    else {
                        $msg .= '"]';
                    }
		}
		if ($err eq "0") { # is 'warning' (not info)
		    carp $msg if $pw;
		}
		else {
		    my $do_croak = 1;
		    if (my $subsub = $h->{'HandleError'}) {
			$do_croak = 0 if &$subsub($msg,$h,$ret[0]);
		    }
		    if ($do_croak) {
			printf $DBI::tfh "    $method_name has failed ($h->{PrintError},$h->{RaiseError})\n"
				if ($DBI::dbi_debug & 0xF) >= 4;
			carp  $msg if $pe;
			die $msg if $h->{RaiseError};
		    }
		}
	    }
	}
    };


    my $method_code = q[
      sub {
        my $h = shift;
	my $h_inner = tied(%$h);
	$h = $h_inner if $h_inner;

        my $imp;
	if ($method_name eq 'DESTROY') {
	    # during global destruction, $h->{...} can trigger "Can't call FETCH on an undef value"
	    # implying that tied() above lied to us, so we need to use eval
	    local $@;	 # protect $@
	    $imp = eval { $h->{"ImplementorClass"} } or return; # probably global destruction
	}
	else {
	    $imp = $h->{"ImplementorClass"} or do {
                warn "Can't call $method_name method on handle $h after take_imp_data()\n"
                    if not exists $h->{Active};
                return; # or, more likely, global destruction
            };
	}

	] . join("\n", '', @pre_call_frag, '') . q[

	my $call_depth = $h->{'dbi_pp_call_depth'} + 1;
	local ($h->{'dbi_pp_call_depth'}) = $call_depth;

	my @ret;
        my $sub = $imp->can($method_name);
        if (!$sub and IMA_FUNC_REDIRECT & $bitmask and $sub = $imp->can('func')) {
            push @_, $method_name;
        }
	if ($sub) {
	    (wantarray) ? (@ret = &$sub($h,@_)) : (@ret = scalar &$sub($h,@_));
	}
	else {
	    # XXX could try explicit fallback to $imp->can('AUTOLOAD') etc
	    # which would then let Multiplex pass PurePerl tests, but some
	    # hook into install_method may be better.
	    croak "Can't locate DBI object method \"$method_name\" via package \"$imp\""
		if ] . ((IMA_NOT_FOUND_OKAY & $bitmask) ? 0 : 1) . q[;
	}

	] . join("\n", '', @post_call_frag, '') . q[

	return (wantarray) ? @ret : $ret[0];
      }
    ];
    no strict qw(refs);
    my $code_ref = eval qq{#line 1 "DBI::PurePerl $method"\n$method_code};
    warn "$@\n$method_code\n" if $@;
    die "$@\n$method_code\n" if $@;
    *$method = $code_ref;
    if (0 && $method =~ /\b(connect|FETCH)\b/) { # debuging tool
	my $l=0; # show line-numbered code for method
	warn "*$method code:\n".join("\n", map { ++$l.": $_" } split/\n/,$method_code);
    }
}


sub _new_handle {
    my ($class, $parent, $attr, $imp_data, $imp_class) = @_;

    DBI->trace_msg("    New $class (for $imp_class, parent=$parent, id=".($imp_data||'').")\n")
        if $DBI::dbi_debug >= 3;

    $attr->{ImplementorClass} = $imp_class
        or Carp::croak("_new_handle($class): 'ImplementorClass' attribute not given");

    # This is how we create a DBI style Object:
    # %outer gets tied to %$attr (which becomes the 'inner' handle)
    my (%outer, $i, $h);
    $i = tie    %outer, $class, $attr;  # ref to inner hash (for driver)
    $h = bless \%outer, $class;         # ref to outer hash (for application)
    # The above tie and bless may migrate down into _setup_handle()...
    # Now add magic so DBI method dispatch works
    DBI::_setup_handle($h, $imp_class, $parent, $imp_data);
    return $h unless wantarray;
    return ($h, $i);
}

sub _setup_handle {
    my($h, $imp_class, $parent, $imp_data) = @_;
    my $h_inner = tied(%$h) || $h;
    if (($DBI::dbi_debug & 0xF) >= 4) {
	local $^W;
	print $DBI::tfh "      _setup_handle(@_)\n";
    }
    $h_inner->{"imp_data"} = $imp_data;
    $h_inner->{"ImplementorClass"} = $imp_class;
    $h_inner->{"Kids"} = $h_inner->{"ActiveKids"} = 0;	# XXX not maintained
    if ($parent) {
	foreach (qw(
	    RaiseError PrintError PrintWarn HandleError HandleSetErr
	    Warn LongTruncOk ChopBlanks AutoCommit ReadOnly
	    ShowErrorStatement FetchHashKeyName LongReadLen CompatMode
	)) {
	    $h_inner->{$_} = $parent->{$_}
		if exists $parent->{$_} && !exists $h_inner->{$_};
	}
	if (ref($parent) =~ /::db$/) { # is sth
	    $h_inner->{Database} = $parent;
	    $parent->{Statement} = $h_inner->{Statement};
	    $h_inner->{NUM_OF_PARAMS} = 0;
            $h_inner->{Active} = 0; # driver sets true when there's data to fetch
	}
	elsif (ref($parent) =~ /::dr$/){ # is dbh
	    $h_inner->{Driver} = $parent;
            $h_inner->{Active} = 0;
	}
        else {
            warn "panic: ".ref($parent); # should never happen
        }
	$h_inner->{dbi_pp_parent} = $parent;

	# add to the parent's ChildHandles
	if ($HAS_WEAKEN) {
	    my $handles = $parent->{ChildHandles} ||= [];
	    push @$handles, $h;
	    Scalar::Util::weaken($handles->[-1]);
	    # purge destroyed handles occasionally
	    if (@$handles % 120 == 0) {
		@$handles = grep { defined } @$handles;
		Scalar::Util::weaken($_) for @$handles; # re-weaken after grep
	    }
	}
    }
    else {	# setting up a driver handle
        $h_inner->{Warn}		= 1;
        $h_inner->{PrintWarn}		= 1;
        $h_inner->{AutoCommit}		= 1;
        $h_inner->{TraceLevel}		= 0;
        $h_inner->{CompatMode}		= (1==0);
	$h_inner->{FetchHashKeyName}	||= 'NAME';
	$h_inner->{LongReadLen}		||= 80;
	$h_inner->{ChildHandles}        ||= [] if $HAS_WEAKEN;
	$h_inner->{Type}                ||= 'dr';
        $h_inner->{Active}              = 1;
    }
    $h_inner->{"dbi_pp_call_depth"} = 0;
    $h_inner->{"dbi_pp_pid"} = $$;
    $h_inner->{ErrCount} = 0;
}

sub constant {
    warn "constant(@_) called unexpectedly"; return undef;
}

sub trace {
    my ($h, $level, $file) = @_;
    $level = $h->parse_trace_flags($level)
	if defined $level and !DBI::looks_like_number($level);
    my $old_level = $DBI::dbi_debug;
    _set_trace_file($file) if $level;
    if (defined $level) {
	$DBI::dbi_debug = $level;
	print $DBI::tfh "    DBI $DBI::VERSION (PurePerl) "
                . "dispatch trace level set to $DBI::dbi_debug\n"
		if $DBI::dbi_debug & 0xF;
    }
    _set_trace_file($file) if !$level;
    return $old_level;
}

sub _set_trace_file {
    my ($file) = @_;
    #
    #   DAA add support for filehandle inputs
    #
    # DAA required to avoid closing a prior fh trace()
    $DBI::tfh = undef unless $DBI::tfh_needs_close;

    if (ref $file eq 'GLOB') {
	$DBI::tfh = $file;
        select((select($DBI::tfh), $| = 1)[0]);
        $DBI::tfh_needs_close = 0;
        return 1;
    }
    if ($file && ref \$file eq 'GLOB') {
	$DBI::tfh = *{$file}{IO};
        select((select($DBI::tfh), $| = 1)[0]);
        $DBI::tfh_needs_close = 0;
        return 1;
    }
    $DBI::tfh_needs_close = 1;
    if (!$file || $file eq 'STDERR') {
	open $DBI::tfh, ">&STDERR" or carp "Can't dup STDERR: $!";
    }
    elsif ($file eq 'STDOUT') {
	open $DBI::tfh, ">&STDOUT" or carp "Can't dup STDOUT: $!";
    }
    else {
        open $DBI::tfh, ">>$file" or carp "Can't open $file: $!";
    }
    select((select($DBI::tfh), $| = 1)[0]);
    return 1;
}
sub _get_imp_data {  shift->{"imp_data"}; }
sub _svdump       { }
sub dump_handle   {
    my ($h,$msg,$level) = @_;
    $msg||="dump_handle $h";
    print $DBI::tfh "$msg:\n";
    for my $attrib (sort keys %$h) {
	print $DBI::tfh "\t$attrib => ".DBI::neat($h->{$attrib})."\n";
    }
}

sub _handles {
    my $h = shift;
    my $h_inner = tied %$h;
    if ($h_inner) {	# this is okay
	return $h unless wantarray;
	return ($h, $h_inner);
    }
    # XXX this isn't okay... we have an inner handle but
    # currently have no way to get at its outer handle,
    # so we just warn and return the inner one for both...
    Carp::carp("Can't return outer handle from inner handle using DBI::PurePerl");
    return $h unless wantarray;
    return ($h,$h);
}

sub hash {
    my ($key, $type) = @_;
    my ($hash);
    if (!$type) {
        $hash = 0;
        # XXX The C version uses the "char" type, which could be either
        # signed or unsigned.  I use signed because so do the two
        # compilers on my system.
        for my $char (unpack ("c*", $key)) {
            $hash = $hash * 33 + $char;
        }
        $hash &= 0x7FFFFFFF;    # limit to 31 bits
        $hash |= 0x40000000;    # set bit 31
        return -$hash;          # return negative int
    }
    elsif ($type == 1) {	# Fowler/Noll/Vo hash
        # see http://www.isthe.com/chongo/tech/comp/fnv/
        require Math::BigInt;   # feel free to reimplement w/o BigInt!
	(my $version = $Math::BigInt::VERSION || 0) =~ s/_.*//; # eg "1.70_01"
	if ($version >= 1.56) {
	    $hash = Math::BigInt->new(0x811c9dc5);
	    for my $uchar (unpack ("C*", $key)) {
		# multiply by the 32 bit FNV magic prime mod 2^64
		$hash = ($hash * 0x01000193) & 0xffffffff;
		# xor the bottom with the current octet
		$hash ^= $uchar;
	    }
	    # cast to int
	    return unpack "i", pack "i", $hash;
	}
	croak("DBI::PurePerl doesn't support hash type 1 without Math::BigInt >= 1.56 (available on CPAN)");
    }
    else {
        croak("bad hash type $type");
    }
}

sub looks_like_number {
    my @new = ();
    for my $thing(@_) {
        if (!defined $thing or $thing eq '') {
            push @new, undef;
        }
        else {
            push @new, ($thing =~ /^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/) ? 1 : 0;
        }
    }
    return (@_ >1) ? @new : $new[0];
}

sub neat {
    my $v = shift;
    return "undef" unless defined $v;
    my $quote = q{"};
    if (not utf8::is_utf8($v)) {
        return $v if (($v & ~ $v) eq "0"); # is SvNIOK
        $quote = q{'};
    }
    my $maxlen = shift || $DBI::neat_maxlen;
    if ($maxlen && $maxlen < length($v) + 2) {
	$v = substr($v,0,$maxlen-5);
	$v .= '...';
    }
    $v =~ s/[^[:print:]]/./g;
    return "$quote$v$quote";
}

sub sql_type_cast {
    my (undef, $sql_type, $flags) = @_;

    return -1 unless defined $_[0];

    my $cast_ok = 1;

    my $evalret = eval {
        use warnings FATAL => qw(numeric);
        if ($sql_type == SQL_INTEGER) {
            my $dummy = $_[0] + 0;
            return 1;
        }
        elsif ($sql_type == SQL_DOUBLE) {
            my $dummy = $_[0] + 0.0;
            return 1;
        }
        elsif ($sql_type == SQL_NUMERIC) {
            my $dummy = $_[0] + 0.0;
            return 1;
        }
        else {
            return -2;
        }
    } or $^W && warn $@; # XXX warnings::warnif("numeric", $@) ?

    return $evalret if defined($evalret) && ($evalret == -2);
    $cast_ok = 0 unless $evalret;

    # DBIstcf_DISCARD_STRING not supported for PurePerl currently

    return 2 if $cast_ok;
    return 0 if $flags & DBIstcf_STRICT;
    return 1;
}

sub dbi_time {
    return time();
}

sub DBI::st::TIEHASH { bless $_[1] => $_[0] };

sub _concat_hash_sorted {
    my ( $hash_ref, $kv_separator, $pair_separator, $use_neat, $num_sort ) = @_;
    # $num_sort: 0=lexical, 1=numeric, undef=try to guess

    return undef unless defined $hash_ref;
    die "hash is not a hash reference" unless ref $hash_ref eq 'HASH';
    my $keys = _get_sorted_hash_keys($hash_ref, $num_sort);
    my $string = '';
    for my $key (@$keys) {
        $string .= $pair_separator if length $string > 0;
        my $value = $hash_ref->{$key};
        if ($use_neat) {
            $value = DBI::neat($value, 0);
        }
        else {
            $value = (defined $value) ? "'$value'" : 'undef';
        }
        $string .= $key . $kv_separator . $value;
    }
    return $string;
}

sub _get_sorted_hash_keys {
    my ($hash_ref, $num_sort) = @_;
    if (not defined $num_sort) {
        my $sort_guess = 1;
        $sort_guess = (not looks_like_number($_)) ? 0 : $sort_guess
            for keys %$hash_ref;
        $num_sort = $sort_guess;
    }

    my @keys = keys %$hash_ref;
    no warnings 'numeric';
    my @sorted = ($num_sort)
        ? sort { $a <=> $b or $a cmp $b } @keys
        : sort    @keys;
    return \@sorted;
}

sub _err_hash {
    return 1 unless defined $_[0]->{err};
    return "$_[0]->{err} $_[0]->{errstr}"
}


package
	DBI::var;

sub FETCH {
    my($key)=shift;
    return $DBI::err     if $$key eq '*err';
    return $DBI::errstr  if $$key eq '&errstr';
    Carp::confess("FETCH $key not supported when using DBI::PurePerl");
}

package
	DBD::_::common;

sub swap_inner_handle {
    my ($h1, $h2) = @_;
    # can't make this work till we can get the outer handle from the inner one
    # probably via a WeakRef
    return $h1->set_err($DBI::stderr, "swap_inner_handle not currently supported by DBI::PurePerl");
}

sub trace {	# XXX should set per-handle level, not global
    my ($h, $level, $file) = @_;
    $level = $h->parse_trace_flags($level)
	if defined $level and !DBI::looks_like_number($level);
    my $old_level = $DBI::dbi_debug;
    DBI::_set_trace_file($file) if defined $file;
    if (defined $level) {
	$DBI::dbi_debug = $level;
	if ($DBI::dbi_debug) {
	    printf $DBI::tfh
		"    %s trace level set to %d in DBI $DBI::VERSION (PurePerl)\n",
		$h, $DBI::dbi_debug;
	    print $DBI::tfh "    Full trace not available because DBI_TRACE is not in environment\n"
		unless exists $ENV{DBI_TRACE};
	}
    }
    return $old_level;
}
*debug = \&trace; *debug = \&trace; # twice to avoid typo warning

sub FETCH {
    my($h,$key)= @_;
    my $v = $h->{$key};
    #warn ((exists $h->{$key}) ? "$key=$v\n" : "$key NONEXISTANT\n");
    return $v if defined $v;
    if ($key =~ /^NAME_.c$/) {
        my $cols = $h->FETCH('NAME');
        return undef unless $cols;
        my @lcols = map { lc $_ } @$cols;
        $h->{NAME_lc} = \@lcols;
        my @ucols = map { uc $_ } @$cols;
        $h->{NAME_uc} = \@ucols;
        return $h->FETCH($key);
    }
    if ($key =~ /^NAME.*_hash$/) {
        my $i=0;
        for my $c(@{$h->FETCH('NAME')||[]}) {
            $h->{'NAME_hash'}->{$c}    = $i;
            $h->{'NAME_lc_hash'}->{"\L$c"} = $i;
            $h->{'NAME_uc_hash'}->{"\U$c"} = $i;
            $i++;
        }
        return $h->{$key};
    }
    if (!defined $v && !exists $h->{$key}) {
	return ($h->FETCH('TaintIn') && $h->FETCH('TaintOut')) if $key eq'Taint';
	return (1==0) if $is_flag_attribute{$key}; # return perl-style sv_no, not undef
	return $DBI::dbi_debug if $key eq 'TraceLevel';
        return [] if $key eq 'ChildHandles' && $HAS_WEAKEN;
        if ($key eq 'Type') {
            return "dr" if $h->isa('DBI::dr');
            return "db" if $h->isa('DBI::db');
            return "st" if $h->isa('DBI::st');
            Carp::carp( sprintf "Can't determine Type for %s",$h );
        }
	if (!$is_valid_attribute{$key} and $key =~ m/^[A-Z]/) {
	    local $^W; # hide undef warnings
	    Carp::carp( sprintf "Can't get %s->{%s}: unrecognised attribute (@{[ %$h ]})",$h,$key )
	}
    }
    return $v;
}
sub STORE {
    my ($h,$key,$value) = @_;
    if ($key eq 'AutoCommit') {
        Carp::croak("DBD driver has not implemented the AutoCommit attribute")
	    unless $value == -900 || $value == -901;
	$value = ($value == -901);
    }
    elsif ($key =~ /^Taint/ ) {
	Carp::croak(sprintf "Can't set %s->{%s}: Taint mode not supported by DBI::PurePerl",$h,$key)
		if $value;
    }
    elsif ($key eq 'TraceLevel') {
	$h->trace($value);
	return 1;
    }
    elsif ($key eq 'NUM_OF_FIELDS') {
        $h->{$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 : $value;
    return 1;
}
sub DELETE {
    my ($h, $key) = @_;
    return $h->FETCH($key) unless $key =~ /^private_/;
    return delete $h->{$key};
}
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 ending 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::_::dr;

sub dbixs_revision {
    return 0;
}

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__