return shift @{$self->{stashed_objects}};
}
-# takes a single DBI-row of data and coinstructs as many objects
-# as the resultset attributes call for.
-# This can be a bit of an action at a distance - it takes as an argument
-# the *current* cursor-row (already taken off the $sth), but if
-# collapsing is requested it will keep advancing the cursor either
-# until the current row-object is assembled (the collapser was able to
-# order the result sensibly) OR until the cursor is exhausted (an
-# unordered collapsing resultset effectively triggers ->all)
+# Constructs as many objects as it can in one pass while respecting
+# cursor laziness. Several modes of operation:
+#
+# * Always builds everything present in @{$self->{stashed_rows}}
+# * If called with $fetch_all true - pulls everything off the cursor and
+# builds all objects in one pass
+# * If $self->_resolved_attrs->{collapse} is true, checks the order_by
+# and if the resultset is ordered properly by the left side:
+# * Fetches stuff off the cursor until the "master object" changes,
+# and saves the last extra row (if any) in @{$self->{stashed_rows}}
+# OR
+# * Just fetches, and collapses/constructs everything as if $fetch_all
+# was requested (there is no other way to collapse except for an
+# eager cursor)
+# * If no collapse is requested - just get the next row, construct and
+# return
sub _construct_objects {
my ($self, $fetch_all) = @_;
# a suprising amount actually
my $rows = (delete $self->{stashed_rows}) || [];
if ($fetch_all) {
- # FIXME - we can do better, cursor->next/all (well diff. methods) should return a ref
+ # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
$rows = [ @$rows, $cursor->all ];
}
elsif (!$attrs->{collapse}) {
+ # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
push @$rows, do { my @r = $cursor->next; @r ? \@r : () }
unless @$rows;
}
}
# since all we check here are the start of the order_by belonging to the
- # top level $rsrc, the order stability check will fail unless the whole
- # thing is ordered as we need it
+ # top level $rsrc, a present identifying set will mean that the resultset
+ # is ordered by its leftmost table in a tsable manner
(@ord_cols and $rsrc->_identifying_column_set({ map
{ $colinfos->{$_}{-colname} => $colinfos->{$_} }
@ord_cols
push @$rows, do { my @r = $cursor->next; @r ? \@r : () };
}
# instead of looping over ->next, use ->all in stealth mode
+ # FIXME - encapsulation breach, got to be a better way
elsif (! $cursor->{done}) {
push @$rows, $cursor->all;
$cursor->{done} = 1;
selection => $attrs->{select},
collapse => $attrs->{collapse},
}) or die $@)->($rows, $fetch_all ? () : (
- sub { my @r = $cursor->next or return; \@r },
- ($self->{stashed_rows} = []),
+ # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
+ sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
+ ($self->{stashed_rows} = []), # where does it stuff excess
)); # modify $rows in-place, shrinking/extending as necessary
$_ = $inflator->($res_class, $rsrc, @$_) for @$rows;
}
}
-# Takes a selection list and generates a collapse-map representing
+# Takes an arrayref selection list and generates a collapse-map representing
# row-object fold-points. Every relationship is assigned a set of unique,
# non-nullable columns (which may *not even be* from the same resultset)
# and the collapser will use this information to correctly distinguish
-# data of individual to-be-row-objects.
+# data of individual to-be-row-objects. See t/resultset/rowparser_internals.t
+# for extensive RV examples
sub _resolve_collapse {
my ($self, $as, $as_fq_idx, $rel_chain, $parent_info, $node_idx_ref) = @_;
}
# Takes an arrayref of {as} dbic column aliases and the collapse and select
-# attributes from the same $rs (the slector requirement is a temporary
-# workaround), and returns a coderef capable of:
-# my $me_pref_clps = $coderef->([$rs->cursor->next])
-# Where the $me_pref_clps arrayref is the future argument to
-# ::ResultSet::_collapse_result.
-#
-# $me_pref_clps->[0] is always returned (even if as an empty hash with no
-# rowdata), however branches of related data in $me_pref_clps->[1] may be
-# pruned short of what was originally requested based on {as}, depending
-# on:
-#
-# * If collapse is requested, a definitive collapse map is calculated for
-# every relationship "fold-point", consisting of a set of values (which
-# may not even be contained in the future 'me' of said relationship
-# (for example a cd.artist_id defines the related inner-joined artist)).
-# Thus a definedness check is carried on all collapse-condition values
-# and if at least one is undef it is assumed that we are dealing with a
-# NULLed right-side of a left-join, so we don't return a related data
-# container at all, which implies no related objects
-#
-# * If we are not collapsing, there is no constraint on having a selector
-# uniquely identifying all possible objects, and the user might have very
-# well requested a column that just *happens* to be all NULLs. What we do
-# in this case is fallback to the old behavior (which is a potential FIXME)
-# by always returning a data container, but only filling it with columns
-# IFF at least one of them is defined. This way we do not get an object
-# with a bunch of has_column_loaded to undef, but at the same time do not
-# further relationships based off this "null" object (e.g. in case the user
-# deliberately skipped link-table values). I am pretty sure there are some
-# tests that codify this behavior, need to find the exact testname.
+# attributes from the same $rs (the selector requirement is a temporary
+# workaround... I hope), and returns a coderef capable of:
+# my $me_pref_clps = $coderef->([$rs->cursor->next/all])
+# Where the $me_pref_clps arrayref is the future argument to inflate_result()
#
# For an example of this coderef in action (and to see its guts) look at
-# t/prefetch/_internals.t
+# t/resultset/rowparser_internals.t
#
-# This is a huge performance win, as we call the same code for
-# every row returned from the db, thus avoiding repeated method
-# lookups when traversing relationships
+# This is a huge performance win, as we call the same code for # every row
+# returned from the db, thus avoiding repeated method lookups when traversing
+# relationships
#
# Also since the coderef is completely stateless (the returned structure is
# always fresh on every new invocation) this is a very good opportunity for
# memoization if further speed improvements are needed
#
-# The way we construct this coderef is somewhat fugly, although I am not
-# sure if the string eval is *that* bad of an idea. The alternative is to
-# have a *very* large number of anon coderefs calling each other in a twisty
-# maze, whereas the current result is a nice, smooth, single-pass function.
+# The way we construct this coderef is somewhat fugly, although the result is
+# really worth it. The final coderef does not perform any kind of recursion -
+# the entire nested structure constructor is rolled out into a single scope.
+#
# In any case - the output of this thing is meticulously micro-tested, so
-# any sort of rewrite should be relatively easy
+# any sort of adjustment/rewrite should be relatively easy (fsvo relatively)
#
sub _mk_row_parser {
my ($self, $args) = @_;
( 0 .. $#{$args->{inflate_map}} )
};
- my ($parser_src);
- if ($args->{collapse}) {
+ my $parser_src;
+
+ # the non-collapsing assembler is easy
+ # FIXME SUBOPTIMAL there could be a yet faster way to do things here, but
+ # need to try an actual implementation and benchmark it:
+ #
+ # <timbunce_> First setup the nested data structure you want for each row
+ # Then call bind_col() to alias the row fields into the right place in
+ # the data structure, then to fetch the data do:
+ # push @rows, dclone($row_data_struct) while ($sth->fetchrow);
+ #
+ if (!$args->{collapse}) {
+ $parser_src = sprintf('$_ = %s for @{$_[0]}', __visit_infmap_simple(
+ $inflate_index,
+ { rsrc => $self }, # need the $rsrc to sanity-check inflation map once
+ ));
+
+ # change the quoted placeholders to unquoted alias-references
+ $parser_src =~ s/ \' \xFF__VALPOS__(\d+)__\xFF \' /"\$_->[$1]"/gex;
+ }
+
+ # the collapsing parser is more complicated - it needs to keep a lot of state
+ #
+ else {
my $collapse_map = $self->_resolve_collapse (
# FIXME
# alias random crap to existing column names anyway, but still - just in
# case
# FIXME !!!! - this does not yet deal with unbalanced selectors correctly
- # (it is now trivial as the attrs specify where things go out of sync)
+ # (it is now trivial as the attrs specify where things go out of sync
+ # needs MOAR tests)
{ map
{ ref $args->{selection}[$inflate_index->{$_}] ? () : ( $_ => $inflate_index->{$_} ) }
keys %$inflate_index
### END STRING EVAL
EOS
+ # !!! note - different var than the one above
# change the quoted placeholders to unquoted alias-references
$parser_src =~ s/ \' \xFF__VALPOS__(\d+)__\xFF \' /"\$cur_row->[$1]"/gex;
$parser_src =~ s/ \' \xFF__IDVALPOS__(\d+)__\xFF \' /"\$cur_row_ids[$1]"/gex;
}
- else {
- $parser_src = sprintf('$_ = %s for @{$_[0]}', __visit_infmap_simple(
- $inflate_index, { rsrc => $self }), # need the $rsrc to determine left-ness
- );
-
- # change the quoted placeholders to unquoted alias-references
- # !!! note - different var than the one above
- $parser_src =~ s/ \' \xFF__VALPOS__(\d+)__\xFF \' /"\$_->[$1]"/gex;
- }
-
$parser_src;
}
+# the simple non-collapsing nested structure recursor
sub __visit_infmap_simple {
my ($val_idx, $args) = @_;
my @relperl;
for my $rel (sort keys %$rel_cols) {
- my $rel_rsrc = __get_related_source($args->{rsrc}, $rel, $rel_cols->{$rel});
-
+ # DISABLEPRUNE
#my $optional = $args->{is_optional};
#$optional ||= ($args->{rsrc}->relationship_info($rel)->{attrs}{join_type} || '') =~ /^left/i;
push @relperl, join ' => ', perlstring($rel), __visit_infmap_simple($rel_cols->{$rel}, {
- non_top => 1,
+ rsrc => __get_related_source($args->{rsrc}, $rel, $rel_cols->{$rel}),
+ # DISABLEPRUNE
+ #non_top => 1,
#is_optional => $optional,
- rsrc => $rel_rsrc,
});
- # FIXME SUBOPTIMAL - disabled to satisfy t/resultset/inflate_result_api.t
+ # FIXME SUBOPTIMAL DISABLEPRUNE - disabled to satisfy t/resultset/inflate_result_api.t
#if ($optional and my @branch_null_checks = map
# { "(! defined '\xFF__VALPOS__${_}__\xFF')" }
# sort { $a <=> $b } values %{$rel_cols->{$rel}}
);
}
+# the collapsing nested structure recursor
sub __visit_infmap_collapse {
my ($val_idx, $collapse_map, $parent_info) = @_;
);
}
+ # DISABLEPRUNE
#my $known_defined = { %{ $parent_info->{known_defined} || {} } };
#$known_defined->{$_}++ for @{$collapse_map->{-node_id}};
node_idx => $collapse_map->{-node_index},
sequenced_node_id => $sequenced_node_id,
relname => $rel,
+ # DISABLEPRUNE
#known_defined => $known_defined,
});
- # FIXME SUBOPTIMAL - disabled to satisfy t/resultset/inflate_result_api.t
+ # FIXME SUBOPTIMAL DISABLEPRUNE - disabled to satisfy t/resultset/inflate_result_api.t
#if ($collapse_map->{$rel}{-is_optional} and my @null_checks = map
# { "(! defined '\xFF__IDVALPOS__${_}__\xFF')" }
# sort { $a <=> $b } grep
($dumper_obj ||= do {
require Data::Dumper;
Data::Dumper->new([])
- ->Useperl (1)
+ ->Useperl (0)
->Purity (1)
->Pad ('')
->Useqq (0)
projects / dbsrgits/DBIx-Class.git / commitdiff