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# (c) Sound Object Logic 2000-2001
use strict;
package Tangram::Hash;
use Tangram::AbstractHash;
use vars qw(@ISA);
@ISA = qw( Tangram::AbstractHash );
use Carp;
sub reschema
{
my ($self, $members, $class, $schema) = @_;
foreach my $member (keys %$members)
{
my $def = $members->{$member};
unless (ref($def))
{
$def = { class => $def };
$members->{$member} = $def;
}
$def->{table} ||= $schema->{normalize}->($def->{class} . "_$member", 'tablename');
$def->{coll} ||= 'coll';
$def->{item} ||= 'item';
$def->{slot} ||= 'slot';
$def->{quote} = !exists $def->{key_type} || $def->{key_type} eq 'string' ? "'" : '';
}
return keys %$members;
}
sub defered_save {
my ($self, $obj, $field, $storage) = @_;
my $coll_id = $storage->export_object($obj);
my ($table, $coll_col, $item_col, $slot_col) = @{ $self }{ qw( table coll item slot ) };
my $Q = $self->{quote};
my $coll = $obj->{$field};
my $old_state = $self->get_load_state($storage, $obj, $field) || {};
my %removed = %$old_state;
delete @removed{ keys %$coll };
my @free = keys %removed;
my %new_state;
foreach my $slot (keys %$coll)
{
my $item_id = $storage->export_object($coll->{$slot});
if (exists $old_state->{$slot})
{
# key already exists
if ($item_id != $old_state->{$slot})
{
# val has changed
$storage->sql_do(
"UPDATE $table SET $item_col = $item_id WHERE $coll_col = $coll_id AND $slot_col = $Q$slot$Q" );
}
}
else
{
# key does not exist
if (@free)
{
# recycle an existing line
my $rslot = shift @free;
$storage->sql_do(
"UPDATE $table SET $slot_col = $Q$slot$Q, $item_col = $item_id WHERE $coll_col = $coll_id AND $slot_col = $Q$rslot$Q" );
}
else
{
# insert a new line
$storage->sql_do(
"INSERT INTO $table ($coll_col, $item_col, $slot_col) VALUES ($coll_id, $item_id, $Q$slot$Q)" );
}
}
$new_state{$slot} = $item_id;
} # foreach my $slot (keys %$coll)
# remove lines in excess
if (@free)
{
@free = map { "$Q$_$Q" } @free if $Q;
$storage->sql_do( "DELETE FROM $table WHERE $coll_col = $coll_id AND $slot_col IN (@free)" );
}
$self->set_load_state($storage, $obj, $field, \%new_state );
$storage->tx_on_rollback( sub { $self->set_load_state($storage, $obj, $field, $old_state) } );
}
sub erase
{
my ($self, $storage, $obj, $members, $coll_id) = @_;
foreach my $member (keys %$members)
{
my $def = $members->{$member};
my $table = $def->{table} || $def->{class} . "_$member";
my $coll_col = $def->{coll} || 'coll';
my $sql = "DELETE FROM $table WHERE $coll_col = $coll_id";
$storage->sql_do($sql);
}
}
sub cursor # ?? factorize ??
{
my ($self, $def, $storage, $obj, $member) = @_;
my $cursor = Tangram::CollCursor->new($storage, $def->{class}, $storage->{db});
my $coll_id = $storage->export_object($obj);
my $coll_tid = $storage->alloc_table;
my $table = $def->{table};
my $item_tid = $cursor->{TARGET}->object->root_table;
my $coll_col = $def->{coll};
my $item_col = $def->{item};
my $slot_col = $def->{slot};
$cursor->{-coll_tid} = $coll_tid;
$cursor->{-coll_cols} = "t$coll_tid.$slot_col";
$cursor->{-coll_from} = "$table t$coll_tid";
$cursor->{-coll_where} = "t$coll_tid.$coll_col = $coll_id AND t$coll_tid.$item_col = t$item_tid.id";
return $cursor;
}
sub query_expr
{
my ($self, $obj, $members, $tid) = @_;
map { Tangram::CollExpr->new($obj, $_); } values %$members;
}
sub remote_expr
{
my ($self, $obj, $tid) = @_;
Tangram::CollExpr->new($obj, $self);
}
sub prefetch
{
my ($self, $storage, $def, $coll, $class, $member, $filter) = @_;
my $ritem = $storage->remote($def->{class});
# first retrieve the collection-side ids of all objects satisfying $filter
# empty the corresponding prefetch array
my $ids = $storage->my_select_data( cols => [ $coll->{id} ], filter => $filter );
my $prefetch = $storage->{PREFETCH}{$class}{$member} ||= {}; # weakref
while (my ($id) = $ids->fetchrow)
{
$prefetch->{$id} = {};
}
undef $ids;
# now fetch the items
my $cursor = Tangram::Cursor->new($storage, $ritem, $storage->{db});
my $includes = $coll->{$member}->includes($ritem);
# also retrieve collection-side id and index of elmt in sequence
$cursor->retrieve($coll->{id},
Tangram::Number->expr("t$includes->{link_tid}.$def->{slot}") );
$cursor->select($filter ? $filter & $includes : $includes);
while (my $item = $cursor->current)
{
my ($coll_id, $slot) = $cursor->residue;
$prefetch->{$coll_id}{$slot} = $item;
$cursor->next;
}
return $prefetch;
}
$Tangram::Schema::TYPES{hash} = Tangram::Hash->new;
1;
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