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add some comments for the distributive operation and add another test

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Signed-off-by: Robin Appelman <robin@icewind.nl>
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Robin Appelman 2024-02-15 18:16:13 +01:00
parent 1c87cee5ad
commit 3890aa54be
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3 changed files with 54 additions and 4 deletions
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27
lib/private/Files/Search/QueryOptimizer/MergeDistributiveOperations.php
View file

@ -10,7 +10,11 @@ use OCP\Files\Search\ISearchOperator;
/**
* Attempt to transform
*
* (A AND B) OR (A AND C) into A AND (B OR C)
* (A AND B) OR (A AND C) OR (A AND D AND E) into A AND (B OR C OR (D AND E))
*
* This is always valid because logical 'AND' and 'OR' are distributive[1].
*
* [1]: https://en.wikipedia.org/wiki/Distributive_property
*/
class MergeDistributiveOperations extends ReplacingOptimizerStep {
public function processOperator(ISearchOperator &$operator): bool {
@ -18,18 +22,29 @@ class MergeDistributiveOperations extends ReplacingOptimizerStep {
$operator instanceof SearchBinaryOperator &&
$this->isAllSameBinaryOperation($operator->getArguments())
) {
// either 'AND' or 'OR'
$topLevelType = $operator->getType();
// split the arguments into groups that share a first argument
// (we already know that all arguments are binary operators with at least 1 child)
$groups = $this->groupBinaryOperatorsByChild($operator->getArguments(), 0);
$outerOperations = array_map(function (array $operators) use ($topLevelType) {
// no common operations, no need to change anything
if (count($operators) === 1) {
return $operators[0];
}
/** @var ISearchBinaryOperator $firstArgument */
$firstArgument = $operators[0];
$outerType = $firstArgument->getType();
// we already checked that all arguments have the same type, so this type applies for all, either 'AND' or 'OR'
$innerType = $firstArgument->getType();
// the common operation we move out ('A' from the example)
$extractedLeftHand = $firstArgument->getArguments()[0];
// for each argument we remove the extracted operation to get the leftovers ('B', 'C' and '(D AND E)' in the example)
// note that we leave them inside the "inner" binary operation for when the "inner" operation contained more than two parts
// in the (common) case where the "inner" operation only has 1 item left it will be cleaned up in a follow up step
$rightHandArguments = array_map(function (ISearchOperator $inner) {
/** @var ISearchBinaryOperator $inner */
$arguments = $inner->getArguments();
@ -39,12 +54,17 @@ class MergeDistributiveOperations extends ReplacingOptimizerStep {
}
return new SearchBinaryOperator($inner->getType(), $arguments);
}, $operators);
// combine the extracted operation ('A') with the remaining bit ('(B OR C OR (D AND E))')
// note that because of how distribution work, we use the "outer" type "inside" and the "inside" type "outside".
$extractedRightHand = new SearchBinaryOperator($topLevelType, $rightHandArguments);
return new SearchBinaryOperator(
$outerType,
$innerType,
[$extractedLeftHand, $extractedRightHand]
);
}, $groups);
// combine all groups again
$operator = new SearchBinaryOperator($topLevelType, $outerOperations);
parent::processOperator($operator);
return true;
@ -90,7 +110,6 @@ class MergeDistributiveOperations extends ReplacingOptimizerStep {
foreach ($operators as $operator) {
/** @var SearchBinaryOperator|SearchComparison $child */
$child = $operator->getArguments()[$index];
;
$childKey = (string) $child;
$result[$childKey][] = $operator;
}

4
lib/public/Files/Search/ISearchComparison.php
View file

@ -70,6 +70,10 @@ interface ISearchComparison extends ISearchOperator {
* @since 28.0.0
*/
public const COMPARE_DEFINED = 'is-defined';
/**
* @since 29.0.0
*/
public const COMPARE_IN = 'in';
/**

27
tests/lib/Files/Search/QueryOptimizer/MergeDistributiveOperationsTest.php
View file

@ -130,4 +130,31 @@ class MergeDistributiveOperationsTest extends TestCase {
$this->assertEquals('((storage eq 1 and (path eq "foo" or path eq "bar" or path eq "asd")) and mimetype eq "text")', $operator->__toString());
}
public function testMoveInnerOperations() {
$operator = new SearchBinaryOperator(
ISearchBinaryOperator::OPERATOR_OR,
[
new SearchBinaryOperator(ISearchBinaryOperator::OPERATOR_AND, [
new SearchComparison(ISearchComparison::COMPARE_EQUAL, "storage", 1),
new SearchComparison(ISearchComparison::COMPARE_EQUAL, "path", "foo"),
]),
new SearchBinaryOperator(ISearchBinaryOperator::OPERATOR_AND, [
new SearchComparison(ISearchComparison::COMPARE_EQUAL, "storage", 1),
new SearchComparison(ISearchComparison::COMPARE_EQUAL, "path", "bar"),
]),
new SearchBinaryOperator(ISearchBinaryOperator::OPERATOR_AND, [
new SearchComparison(ISearchComparison::COMPARE_EQUAL, "storage", 1),
new SearchComparison(ISearchComparison::COMPARE_EQUAL, "path", "asd"),
new SearchComparison(ISearchComparison::COMPARE_GREATER_THAN, "size", "100"),
])
]
);
$this->assertEquals('((storage eq 1 and path eq "foo") or (storage eq 1 and path eq "bar") or (storage eq 1 and path eq "asd" and size gt "100"))', $operator->__toString());
$this->optimizer->processOperator($operator);
$this->simplifier->processOperator($operator);
$this->assertEquals('(storage eq 1 and (path eq "foo" or path eq "bar" or (path eq "asd" and size gt "100")))', $operator->__toString());
}
}