libs/Tangram/Hash.pm

# (c) Sound Object Logic 2000-2001

use strict;

package Tangram::Hash;

use Tangram::AbstractHash;
use base 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
{
    q{
        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;
        }

    } # skipped
}

$Tangram::Schema::TYPES{hash} = Tangram::Hash->new;

1;
1	# (c) Sound Object Logic 2000-2001
2
3	use strict;
4
5	package Tangram::Hash;
6
7	use Tangram::AbstractHash;
8	use base qw( Tangram::AbstractHash );
9
10	use Carp;
11
12	sub reschema
13	{
14	my ($self, $members, $class, $schema) = @_;
15
16	foreach my $member (keys %$members)
17	{
18	my $def = $members->{$member};
19
20	unless (ref($def))
21	{
22	$def = { class => $def };
23	$members->{$member} = $def;
24	}
25
26	$def->{table} \|\|= $schema->{normalize}->($def->{class} . "_$member", 'tablename');
27	$def->{coll} \|\|= 'coll';
28	$def->{item} \|\|= 'item';
29	$def->{slot} \|\|= 'slot';
30	$def->{quote} = !exists $def->{key_type} \|\| $def->{key_type} eq 'string' ? "'" : '';
31	}
32
33	return keys %$members;
34	}
35
36	sub defered_save {
37	my ($self, $obj, $field, $storage) = @_;
38
39	my $coll_id = $storage->export_object($obj);
40
41	my ($table, $coll_col, $item_col, $slot_col) = @{ $self }{ qw( table coll item slot ) };
42	my $Q = $self->{quote};
43
44	my $coll = $obj->{$field};
45
46	my $old_state = $self->get_load_state($storage, $obj, $field) \|\| {};
47
48	my %removed = %$old_state;
49	delete @removed{ keys %$coll };
50	my @free = keys %removed;
51
52	my %new_state;
53
54	foreach my $slot (keys %$coll)
55	{
56	my $item_id = $storage->export_object($coll->{$slot});
57
58	if (exists $old_state->{$slot})
59	{
60	# key already exists
61
62	if ($item_id != $old_state->{$slot})
63	{
64	# val has changed
65	$storage->sql_do(
66	"UPDATE $table SET $item_col = $item_id WHERE $coll_col = $coll_id AND $slot_col = $Q$slot$Q" );
67	}
68	}
69	else
70	{
71	# key does not exist
72
73	if (@free)
74	{
75	# recycle an existing line
76	my $rslot = shift @free;
77	$storage->sql_do(
78	"UPDATE $table SET $slot_col = $Q$slot$Q, $item_col = $item_id WHERE $coll_col = $coll_id AND $slot_col = $Q$rslot$Q" );
79	}
80	else
81	{
82	# insert a new line
83	$storage->sql_do(
84	"INSERT INTO $table ($coll_col, $item_col, $slot_col) VALUES ($coll_id, $item_id, $Q$slot$Q)" );
85	}
86	}
87
88	$new_state{$slot} = $item_id;
89
90	} # foreach my $slot (keys %$coll)
91
92	# remove lines in excess
93
94	if (@free)
95	{
96	@free = map { "$Q$_$Q" } @free if $Q;
97	$storage->sql_do( "DELETE FROM $table WHERE $coll_col = $coll_id AND $slot_col IN (@free)" );
98	}
99
100	$self->set_load_state($storage, $obj, $field, \%new_state );
101	$storage->tx_on_rollback( sub { $self->set_load_state($storage, $obj, $field, $old_state) } );
102	}
103
104
105	sub erase
106	{
107	my ($self, $storage, $obj, $members, $coll_id) = @_;
108
109	foreach my $member (keys %$members)
110	{
111	my $def = $members->{$member};
112
113	my $table = $def->{table} \|\| $def->{class} . "_$member";
114	my $coll_col = $def->{coll} \|\| 'coll';
115
116	my $sql = "DELETE FROM $table WHERE $coll_col = $coll_id";
117	$storage->sql_do($sql);
118	}
119	}
120
121	sub cursor # ?? factorize ??
122	{
123	my ($self, $def, $storage, $obj, $member) = @_;
124
125	my $cursor = Tangram::CollCursor->new($storage, $def->{class}, $storage->{db});
126
127	my $coll_id = $storage->export_object($obj);
128	my $coll_tid = $storage->alloc_table;
129	my $table = $def->{table};
130	my $item_tid = $cursor->{TARGET}->object->root_table;
131	my $coll_col = $def->{coll};
132	my $item_col = $def->{item};
133	my $slot_col = $def->{slot};
134	$cursor->{-coll_tid} = $coll_tid;
135	$cursor->{-coll_cols} = "t$coll_tid.$slot_col";
136	$cursor->{-coll_from} = "$table t$coll_tid";
137	$cursor->{-coll_where} = "t$coll_tid.$coll_col = $coll_id AND t$coll_tid.$item_col = t$item_tid.id";
138
139	return $cursor;
140	}
141
142	sub query_expr
143	{
144	my ($self, $obj, $members, $tid) = @_;
145	map { Tangram::CollExpr->new($obj, $_); } values %$members;
146	}
147
148	sub remote_expr
149	{
150	my ($self, $obj, $tid) = @_;
151	Tangram::CollExpr->new($obj, $self);
152	}
153
154	sub prefetch
155	{
156	q{
157	my ($self, $storage, $def, $coll, $class, $member, $filter) = @_;
158
159	my $ritem = $storage->remote($def->{class});
160
161	# first retrieve the collection-side ids of all objects satisfying $filter
162	# empty the corresponding prefetch array
163
164	my $ids = $storage->my_select_data( cols => [ $coll->{id} ], filter => $filter );
165	my $prefetch = $storage->{PREFETCH}{$class}{$member} \|\|= {}; # weakref
166
167	while (my $id = $ids->fetchrow)
168	{
169	$prefetch->{$id} = []
170	}
171
172	undef $ids;
173
174	# now fetch the items
175
176	my $cursor = Tangram::Cursor->new($storage, $ritem, $storage->{db});
177	my $includes = $coll->{$member}->includes($ritem);
178
179	# also retrieve collection-side id and index of elmt in sequence
180	$cursor->retrieve($coll->{id},
181	Tangram::Number->expr("t$includes->{link_tid}.$def->{slot}" ) );
182
183	$cursor->select($filter ? $filter & $includes : $includes);
184
185	while (my $item = $cursor->current)
186	{
187	my ($coll_id, $slot) = $cursor->residue;
188	$prefetch->{$coll_id}[$slot] = $item;
189	$cursor->next;
190	}
191
192	} # skipped
193	}
194
195	$Tangram::Schema::TYPES{hash} = Tangram::Hash->new;
196
197	1;
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