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Direktori : /home2/selectio/www/a1tex.in/vendor/nikic/php-parser/lib/PhpParser/ |
Current File : /home2/selectio/www/a1tex.in/vendor/nikic/php-parser/lib/PhpParser/ConstExprEvaluator.php |
<?php namespace PhpParser; use function array_merge; use PhpParser\Node\Expr; use PhpParser\Node\Scalar; /** * Evaluates constant expressions. * * This evaluator is able to evaluate all constant expressions (as defined by PHP), which can be * evaluated without further context. If a subexpression is not of this type, a user-provided * fallback evaluator is invoked. To support all constant expressions that are also supported by * PHP (and not already handled by this class), the fallback evaluator must be able to handle the * following node types: * * * All Scalar\MagicConst\* nodes. * * Expr\ConstFetch nodes. Only null/false/true are already handled by this class. * * Expr\ClassConstFetch nodes. * * The fallback evaluator should throw ConstExprEvaluationException for nodes it cannot evaluate. * * The evaluation is dependent on runtime configuration in two respects: Firstly, floating * point to string conversions are affected by the precision ini setting. Secondly, they are also * affected by the LC_NUMERIC locale. */ class ConstExprEvaluator { private $fallbackEvaluator; /** * Create a constant expression evaluator. * * The provided fallback evaluator is invoked whenever a subexpression cannot be evaluated. See * class doc comment for more information. * * @param callable|null $fallbackEvaluator To call if subexpression cannot be evaluated */ public function __construct(callable $fallbackEvaluator = null) { $this->fallbackEvaluator = $fallbackEvaluator ?? function(Expr $expr) { throw new ConstExprEvaluationException( "Expression of type {$expr->getType()} cannot be evaluated" ); }; } /** * Silently evaluates a constant expression into a PHP value. * * Thrown Errors, warnings or notices will be converted into a ConstExprEvaluationException. * The original source of the exception is available through getPrevious(). * * If some part of the expression cannot be evaluated, the fallback evaluator passed to the * constructor will be invoked. By default, if no fallback is provided, an exception of type * ConstExprEvaluationException is thrown. * * See class doc comment for caveats and limitations. * * @param Expr $expr Constant expression to evaluate * @return mixed Result of evaluation * * @throws ConstExprEvaluationException if the expression cannot be evaluated or an error occurred */ public function evaluateSilently(Expr $expr) { set_error_handler(function($num, $str, $file, $line) { throw new \ErrorException($str, 0, $num, $file, $line); }); try { return $this->evaluate($expr); } catch (\Throwable $e) { if (!$e instanceof ConstExprEvaluationException) { $e = new ConstExprEvaluationException( "An error occurred during constant expression evaluation", 0, $e); } throw $e; } finally { restore_error_handler(); } } /** * Directly evaluates a constant expression into a PHP value. * * May generate Error exceptions, warnings or notices. Use evaluateSilently() to convert these * into a ConstExprEvaluationException. * * If some part of the expression cannot be evaluated, the fallback evaluator passed to the * constructor will be invoked. By default, if no fallback is provided, an exception of type * ConstExprEvaluationException is thrown. * * See class doc comment for caveats and limitations. * * @param Expr $expr Constant expression to evaluate * @return mixed Result of evaluation * * @throws ConstExprEvaluationException if the expression cannot be evaluated */ public function evaluateDirectly(Expr $expr) { return $this->evaluate($expr); } private function evaluate(Expr $expr) { if ($expr instanceof Scalar\LNumber || $expr instanceof Scalar\DNumber || $expr instanceof Scalar\String_ ) { return $expr->value; } if ($expr instanceof Expr\Array_) { return $this->evaluateArray($expr); } // Unary operators if ($expr instanceof Expr\UnaryPlus) { return +$this->evaluate($expr->expr); } if ($expr instanceof Expr\UnaryMinus) { return -$this->evaluate($expr->expr); } if ($expr instanceof Expr\BooleanNot) { return !$this->evaluate($expr->expr); } if ($expr instanceof Expr\BitwiseNot) { return ~$this->evaluate($expr->expr); } if ($expr instanceof Expr\BinaryOp) { return $this->evaluateBinaryOp($expr); } if ($expr instanceof Expr\Ternary) { return $this->evaluateTernary($expr); } if ($expr instanceof Expr\ArrayDimFetch && null !== $expr->dim) { return $this->evaluate($expr->var)[$this->evaluate($expr->dim)]; } if ($expr instanceof Expr\ConstFetch) { return $this->evaluateConstFetch($expr); } return ($this->fallbackEvaluator)($expr); } private function evaluateArray(Expr\Array_ $expr) { $array = []; foreach ($expr->items as $item) { if (null !== $item->key) { $array[$this->evaluate($item->key)] = $this->evaluate($item->value); } elseif ($item->unpack) { $array = array_merge($array, $this->evaluate($item->value)); } else { $array[] = $this->evaluate($item->value); } } return $array; } private function evaluateTernary(Expr\Ternary $expr) { if (null === $expr->if) { return $this->evaluate($expr->cond) ?: $this->evaluate($expr->else); } return $this->evaluate($expr->cond) ? $this->evaluate($expr->if) : $this->evaluate($expr->else); } private function evaluateBinaryOp(Expr\BinaryOp $expr) { if ($expr instanceof Expr\BinaryOp\Coalesce && $expr->left instanceof Expr\ArrayDimFetch ) { // This needs to be special cased to respect BP_VAR_IS fetch semantics return $this->evaluate($expr->left->var)[$this->evaluate($expr->left->dim)] ?? $this->evaluate($expr->right); } // The evaluate() calls are repeated in each branch, because some of the operators are // short-circuiting and evaluating the RHS in advance may be illegal in that case $l = $expr->left; $r = $expr->right; switch ($expr->getOperatorSigil()) { case '&': return $this->evaluate($l) & $this->evaluate($r); case '|': return $this->evaluate($l) | $this->evaluate($r); case '^': return $this->evaluate($l) ^ $this->evaluate($r); case '&&': return $this->evaluate($l) && $this->evaluate($r); case '||': return $this->evaluate($l) || $this->evaluate($r); case '??': return $this->evaluate($l) ?? $this->evaluate($r); case '.': return $this->evaluate($l) . $this->evaluate($r); case '/': return $this->evaluate($l) / $this->evaluate($r); case '==': return $this->evaluate($l) == $this->evaluate($r); case '>': return $this->evaluate($l) > $this->evaluate($r); case '>=': return $this->evaluate($l) >= $this->evaluate($r); case '===': return $this->evaluate($l) === $this->evaluate($r); case 'and': return $this->evaluate($l) and $this->evaluate($r); case 'or': return $this->evaluate($l) or $this->evaluate($r); case 'xor': return $this->evaluate($l) xor $this->evaluate($r); case '-': return $this->evaluate($l) - $this->evaluate($r); case '%': return $this->evaluate($l) % $this->evaluate($r); case '*': return $this->evaluate($l) * $this->evaluate($r); case '!=': return $this->evaluate($l) != $this->evaluate($r); case '!==': return $this->evaluate($l) !== $this->evaluate($r); case '+': return $this->evaluate($l) + $this->evaluate($r); case '**': return $this->evaluate($l) ** $this->evaluate($r); case '<<': return $this->evaluate($l) << $this->evaluate($r); case '>>': return $this->evaluate($l) >> $this->evaluate($r); case '<': return $this->evaluate($l) < $this->evaluate($r); case '<=': return $this->evaluate($l) <= $this->evaluate($r); case '<=>': return $this->evaluate($l) <=> $this->evaluate($r); } throw new \Exception('Should not happen'); } private function evaluateConstFetch(Expr\ConstFetch $expr) { $name = $expr->name->toLowerString(); switch ($name) { case 'null': return null; case 'false': return false; case 'true': return true; } return ($this->fallbackEvaluator)($expr); } }