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Item9808: added regex support to the search. Fixed ref. Getting close!
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git-svn-id: http://svn.foswiki.org/trunk/DBIStoreContrib@17244 0b4bb1d4-4e5a-0410-9cc4-b2b747904278
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CrawfordCurrie authored and CrawfordCurrie committed Jan 17, 2014
1 parent 2006fe1 commit 244e03e
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Showing 3 changed files with 82 additions and 63 deletions.
119 changes: 60 additions & 59 deletions lib/Foswiki/Contrib/DBIStoreContrib/HoistSQL.pm
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Expand Up @@ -10,31 +10,16 @@ query matching.
=cut

=pod
For SQL, at any given point, we need to know the table that is being referenced,the WHERE condition, and the rows being selected from the table.
[ takes a table and a WHERE, and returns a table
. takes a table and a name, and returns a SELECT
>= takes a SELECT and a constant (or a constant and a select, or a select and a select, or a constant and a constant) and returns WHERE
AND takes a WHERE and a WHERE and returns a compound WHERE
Rewriting based on precedence
Adjust precedence before the parse?
=cut

package Foswiki::Contrib::DBIStoreContrib::HoistSQL;

use strict;
use Assert;

use Foswiki::Contrib::DBIStoreContrib ();
use Foswiki::Infix::Node ();
use Foswiki::Query::Node ();
use Foswiki::Query::Parser ();
use Foswiki::Contrib::DBIStoreContrib ();
use Foswiki::Infix::Node ();
use Foswiki::Query::Node ();
use Foswiki::Query::Parser ();
use Foswiki::Store::QueryAlgorithms::DBIStoreContrib ();

# A Foswiki query parser
our $parser;
Expand All @@ -49,9 +34,6 @@ use constant {
NAME => 1,
NUMBER => 2,
STRING => 3,

TABLE_NAME => 4,
SELECTOR => 5
};

BEGIN {
Expand All @@ -76,6 +58,7 @@ to replace any hoisted parts with unconditional true/false values.
=cut

# Operators that can be mapped directly to SQL
my %bop_map = (
and => 'AND',
or => 'OR',
Expand All @@ -92,39 +75,58 @@ my %uop_map = (
length => 'LENGTH'
);

# Types of expansion required during hoisting
use constant {
EXPR => 1,
TABLE => 2
CONDITION => 1,
TABLE => 2,
ROOT => 3
};

my $tempTable = 0;

sub hoist {
my ( $node, $control, $type ) = @_;
$type ||= EXPR; # query algorithm wants a table

# The default context table is 'topic'. As soon as we go into a
# SELECT, the context table may change. In a /, the context table
# is still 'topic'
$type ||= CONDITION; # query algorithm wants a condition

my $op = $node->{op}->{name} if ref( $node->{op} );

my $res;
if ( !ref( $node->{op} ) ) {
$res = _constant( $node, 1, $control );
if ( $type == EXPR ) {
}
else {
}
}
elsif ( $bop_map{$op} ) {
my $lhs = hoist( $node->{params}[0], $control, EXPR );
my $rhs = hoist( $node->{params}[1], $control, EXPR );
ASSERT( $type == CONDITION, $node->stringify() );
my $lhs = hoist( $node->{params}[0], $control, CONDITION );
my $rhs = hoist( $node->{params}[1], $control, CONDITION );
$lhs = "($lhs)" if ref( $node->{params}[0]->{op} );
$rhs = "($rhs)" if ref( $node->{params}[1]->{op} );
$res = "$lhs $bop_map{$op} $rhs";
ASSERT( $type == EXPR, $node->stringify() );
}
elsif ( $op eq '=~' ) {
ASSERT( $type == CONDITION, $node->stringify() );
my $lhs = hoist( $node->{params}[0], $control, CONDITION );
my $rhs = hoist( $node->{params}[1], $control, CONDITION );
$rhs =~ s/^"(.*)"$/$1/;
$res = Foswiki::Contrib::DBIStoreContrib::DBIStore::personality->regexp(
$lhs, $op, $rhs );
}
elsif ( $op eq '~' ) {
ASSERT( $type == CONDITION, $node->stringify() );
my $lhs = hoist( $node->{params}[0], $control, CONDITION );
my $rhs = hoist( $node->{params}[1], $control, CONDITION );
$rhs =~ s/^"(.*)"$/$1/;
$res =
Foswiki::Contrib::DBIStoreContrib::DBIStore::personality->wildcard(
$lhs, $rhs );
}
elsif ( $uop_map{$op} ) {
my $child = hoist( $node->{params}[0], $control );
$res = "$uop_map{$op}($child)";
ASSERT( $type == EXPR, $node->stringify() );
ASSERT( $type == CONDITION, $node->stringify() );
}
elsif ( $op eq '[' ) {
my $lhs = hoist( $node->{params}[0], $control, TABLE );
Expand All @@ -140,10 +142,10 @@ sub hoist {
}
my %sc = %$control;
$sc{table} = $t1;
my $where = hoist( $node->{params}[1], \%sc, EXPR );
my $where = hoist( $node->{params}[1], \%sc, CONDITION );
$res =
"SELECT * from $lhs WHERE $t1.tid=$control->{table}.tid AND $where";
$res = "EXISTS($res)" if ( $type == EXPR );
$res = "EXISTS($res)" if ( $type == CONDITION );
}
elsif ( $op eq '.' ) {
my $lhs = hoist( $node->{params}[0], $control, TABLE );
Expand All @@ -159,20 +161,28 @@ sub hoist {
}
my %sc = %$control;
$sc{table} = $t1;
my $where = hoist( $node->{params}[1], \%sc, EXPR );
my $where = hoist( $node->{params}[1], \%sc, CONDITION );
$res =
"SELECT * FROM $lhs WHERE $t1.tid=$control->{table}.tid AND $where";
$res = "EXISTS($res)" if ( $type == EXPR );
$res = "EXISTS($res)" if ( $type == CONDITION );
}
elsif ( $op eq '/' ) {

# A lookup in another topic
my $t1 = $control->{table};
my $c = _constant( $node->{params}[0], 0 );
my $sc = {
table => $control->{table},
table => $t1,
iwebs => $control->{iweb},
itopics => [ _constant( $node->{params}[0], 0 ) ]
itopics => [$c]
};
$res = hoist( $node->{params}[1], $sc, EXPR );
my $lhs = hoist( $node->{params}[1], $sc, CONDITION );
my $partial = " WHERE";
if ( $t1 ne 'topic' ) {
$partial = ",$t1 WHERE topic.tid=$t1.tid AND";
}
$res =
"EXISTS(SELECT tid FROM topic${partial} topic.name='$c' AND $lhs)";
}
else {
ASSERT( 0, "Don't know how to hoist $op" . recreate($node) );
Expand Down Expand Up @@ -266,28 +276,20 @@ sub _expand_relist {
Rewrite a Foswiki query parse tree to eliminate certain types
of subexpression, and so simplify subsequent SQL extraction.
* X -> fields[name='X'].value
* info.Y -> META:TOPICINFO.Y
* formname.Y -> Y -> fields[name='X'].value
* X.Y => fields[name='X'].Y
* fields[name='X'].Y -> META:FIELD[name='X'].Y
* X[N] -> X[ROW_INDEX='N']
=cut

# SMELL: must clone the query
sub rewrite {
my ( $node, $context ) = @_;

$context ||= 'ROOT';
$context ||= ROOT;

my $before;
$before = recreate($node) if MONITOR;
my $rewrote = 0;

unless ( ref( $node->{op} ) ) {
if ( $node->{op} == NAME ) {
if ( $context eq 'ROOT' ) {
if ( $context == ROOT ) {

# A name floating around in an expression.
$parser ||= new Foswiki::Query::Parser();
Expand All @@ -312,8 +314,8 @@ sub rewrite {
# information to determine how it should be parsed. We don't have
# all that context here, so we have to do the best we can with what
# we have, and rewrite it as a []
my $lhs = rewrite( $node->{params}[0], 'TABLE' );
my $rhs = rewrite( $node->{params}[1], 'SELECTOR' );
my $lhs = rewrite( $node->{params}[0], TABLE );
my $rhs = rewrite( $node->{params}[1], CONDITION );

# RHS must be a key.
die "Illegal RHS of . " . recreate($rhs)
Expand Down Expand Up @@ -354,10 +356,9 @@ sub rewrite {
elsif ( $op eq '[' ) {

# Convert a row number constant into a condition
my $lhs = $node->{params}[0] =
rewrite( $node->{params}[0], 'TABLE' );
my $lhs = $node->{params}[0] = rewrite( $node->{params}[0], TABLE );
my $rhs = $node->{params}[1] =
rewrite( $node->{params}[1], 'WHERE' );
rewrite( $node->{params}[1], CONDITION );
if ( !ref( $lhs->{op} ) && $lhs->{op} == NUMBER ) {
my $n = $lhs->{params}[0];
$node->{params}[1] = $parser->parse("ROW_INDEX=$n");
Expand Down Expand Up @@ -429,8 +430,8 @@ my %reorder = (
# prec gives the new precedence of the operator.
# child gives the index of the subnode that has the
# selector (the RHS for / and . operators).
'/' => { prec => 275, child => 1 },
'.' => { prec => 250, child => 1 }
'/' => { prec => 250, child => 1 },
'.' => { prec => 275, child => 1 }
);

sub reorder {
Expand Down Expand Up @@ -516,7 +517,7 @@ sub recreate {
my @oa;
for ( my $i = 0 ; $i < $node->{op}->{arity} ; $i++ ) {
my $nprec = $node->{op}->{prec};
$nprec++ if $i == 0;
$nprec++ if $i > 0;
$nprec = 0 if $node->{op}->{close};
push( @oa, recreate( $node->{params}[$i], $nprec ) );
}
Expand Down
2 changes: 2 additions & 0 deletions lib/Foswiki/Store/QueryAlgorithms/DBIStoreContrib.pm
View file
Expand Up @@ -181,6 +181,7 @@ sub query {
# Try and hoist regular expressions out of the query that we
# can use to refine the topic set

require Foswiki::Contrib::DBIStoreContrib::HoistSQL;
$query = Foswiki::Contrib::DBIStoreContrib::HoistSQL::rewrite($query);
Foswiki::Contrib::DBIStoreContrib::HoistSQL::reorder( $query, \$query );
print STDERR "Rewritten "
Expand All @@ -191,6 +192,7 @@ sub query {
\%hoist_control )
. ' ORDER BY web,name';

$query = undef; # not needed any more
print STDERR "Generated SQL: $sql\n" if MONITOR;

my $topicSet =
Expand Down
24 changes: 20 additions & 4 deletions test/unit/DBIStoreContrib/DBIStoreContribSuite.pm
View file
Expand Up @@ -11,18 +11,34 @@ use Foswiki::Query::Parser;
use Foswiki::Contrib::DBIStoreContrib::HoistSQL;
my $theParser = new Foswiki::Query::Parser();

# This is an interactive test, allowing you to type in Foswiki queries,
# and inspect the generated SQL and results of the query.
sub test_hoist {
my $this = shift;
print "Enter Foswiki query: ";
my $searchString = <>;
chomp($searchString);
my $query = $theParser->parse( $searchString, {} );
my $rewrite = Foswiki::Contrib::DBIStoreContrib::HoistSQL::_rewrite($query);
print STDERR "Rewritten: " . $rewrite->stringify() . "\n";
my ( $h, @ht ) = Foswiki::Contrib::DBIStoreContrib::HoistSQL::hoist($query);
print STDERR "HOIST $h IN " . join( ',', @ht ) . "\n";

$query = Foswiki::Contrib::DBIStoreContrib::HoistSQL::rewrite($query);
Foswiki::Contrib::DBIStoreContrib::HoistSQL::reorder( $query, \$query );
print STDERR "Rewritten "
. Foswiki::Contrib::DBIStoreContrib::HoistSQL::recreate($query) . "\n";
my $sql = 'SELECT web,name FROM topic WHERE '
. Foswiki::Contrib::DBIStoreContrib::HoistSQL::hoist( $query,
\%hoist_control )
. ' ORDER BY web,name';
print STDERR "Generated SQL: $sql\n";
my $topicSet =
Foswiki::Contrib::DBIStoreContrib::DBIStore::DBI_query( undef, $sql );

foreach my $webtopic (@$topicSet) {
print STDERR "$webtopic\n";
}
}

while (1) {
test_hoist;
}

1;

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