leilukin-tumbleblog/includes/lib/Twig/Node/Expression/Binary/NullCoalesceBinary.php

84 lines
2.7 KiB
PHP

<?php
/*
* This file is part of Twig.
*
* (c) Fabien Potencier
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Twig\Node\Expression\Binary;
use Twig\Compiler;
use Twig\Node\EmptyNode;
use Twig\Node\Expression\AbstractExpression;
use Twig\Node\Expression\BlockReferenceExpression;
use Twig\Node\Expression\NameExpression;
use Twig\Node\Expression\OperatorEscapeInterface;
use Twig\Node\Expression\Test\DefinedTest;
use Twig\Node\Expression\Test\NullTest;
use Twig\Node\Expression\Unary\NotUnary;
use Twig\TwigTest;
final class NullCoalesceBinary extends AbstractBinary implements OperatorEscapeInterface
{
public function __construct(AbstractExpression $left, AbstractExpression $right, int $lineno)
{
parent::__construct($left, $right, $lineno);
if (!$left instanceof NameExpression) {
$test = new DefinedTest(clone $left, new TwigTest('defined'), new EmptyNode(), $left->getTemplateLine());
// for "block()", we don't need the null test as the return value is always a string
if (!$left instanceof BlockReferenceExpression) {
$test = new AndBinary(
$test,
new NotUnary(new NullTest($left, new TwigTest('null'), new EmptyNode(), $left->getTemplateLine()), $left->getTemplateLine()),
$left->getTemplateLine(),
);
}
$this->setNode('test', $test);
} else {
$left->setAttribute('always_defined', true);
}
}
public function compile(Compiler $compiler): void
{
/*
* This optimizes only one case. PHP 7 also supports more complex expressions
* that can return null. So, for instance, if log is defined, log("foo") ?? "..." works,
* but log($a["foo"]) ?? "..." does not if $a["foo"] is not defined. More advanced
* cases might be implemented as an optimizer node visitor, but has not been done
* as benefits are probably not worth the added complexity.
*/
if ($this->hasNode('test')) {
$compiler
->raw('((')
->subcompile($this->getNode('test'))
->raw(') ? (')
->subcompile($this->getNode('left'))
->raw(') : (')
->subcompile($this->getNode('right'))
->raw('))')
;
return;
}
parent::compile($compiler);
}
public function operator(Compiler $compiler): Compiler
{
return $compiler->raw('??');
}
public function getOperandNamesToEscape(): array
{
return $this->hasNode('test') ? ['left', 'right'] : ['right'];
}
}