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Diffstat (limited to 'vendor/nikic/php-parser/lib/PhpParser/ConstExprEvaluator.php')
| -rw-r--r-- | vendor/nikic/php-parser/lib/PhpParser/ConstExprEvaluator.php | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/vendor/nikic/php-parser/lib/PhpParser/ConstExprEvaluator.php b/vendor/nikic/php-parser/lib/PhpParser/ConstExprEvaluator.php new file mode 100644 index 000000000..7131c3d25 --- /dev/null +++ b/vendor/nikic/php-parser/lib/PhpParser/ConstExprEvaluator.php @@ -0,0 +1,229 @@ +<?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); + } +} |