Chris@13: <?php
Chris@13: 
Chris@13: /*
Chris@13:  * This file is part of Psy Shell.
Chris@13:  *
Chris@13:  * (c) 2012-2018 Justin Hileman
Chris@13:  *
Chris@13:  * For the full copyright and license information, please view the LICENSE
Chris@13:  * file that was distributed with this source code.
Chris@13:  */
Chris@13: 
Chris@13: namespace Psy\CodeCleaner;
Chris@13: 
Chris@13: use PhpParser\Node;
Chris@13: use PhpParser\Node\Scalar\DNumber;
Chris@13: use PhpParser\Node\Scalar\LNumber;
Chris@13: use PhpParser\Node\Stmt\Break_;
Chris@13: use PhpParser\Node\Stmt\Continue_;
Chris@13: use PhpParser\Node\Stmt\Do_;
Chris@13: use PhpParser\Node\Stmt\For_;
Chris@13: use PhpParser\Node\Stmt\Foreach_;
Chris@13: use PhpParser\Node\Stmt\Switch_;
Chris@13: use PhpParser\Node\Stmt\While_;
Chris@13: use Psy\Exception\FatalErrorException;
Chris@13: 
Chris@13: /**
Chris@13:  * The loop context pass handles invalid `break` and `continue` statements.
Chris@13:  */
Chris@13: class LoopContextPass extends CodeCleanerPass
Chris@13: {
Chris@13:     private $loopDepth;
Chris@13: 
Chris@13:     /**
Chris@13:      * {@inheritdoc}
Chris@13:      */
Chris@13:     public function beforeTraverse(array $nodes)
Chris@13:     {
Chris@13:         $this->loopDepth = 0;
Chris@13:     }
Chris@13: 
Chris@13:     /**
Chris@13:      * @throws FatalErrorException if the node is a break or continue in a non-loop or switch context
Chris@13:      * @throws FatalErrorException if the node is trying to break out of more nested structures than exist
Chris@13:      * @throws FatalErrorException if the node is a break or continue and has a non-numeric argument
Chris@13:      * @throws FatalErrorException if the node is a break or continue and has an argument less than 1
Chris@13:      *
Chris@13:      * @param Node $node
Chris@13:      */
Chris@13:     public function enterNode(Node $node)
Chris@13:     {
Chris@13:         switch (true) {
Chris@13:             case $node instanceof Do_:
Chris@13:             case $node instanceof For_:
Chris@13:             case $node instanceof Foreach_:
Chris@13:             case $node instanceof Switch_:
Chris@13:             case $node instanceof While_:
Chris@13:                 $this->loopDepth++;
Chris@13:                 break;
Chris@13: 
Chris@13:             case $node instanceof Break_:
Chris@13:             case $node instanceof Continue_:
Chris@13:                 $operator = $node instanceof Break_ ? 'break' : 'continue';
Chris@13: 
Chris@13:                 if ($this->loopDepth === 0) {
Chris@17:                     $msg = \sprintf("'%s' not in the 'loop' or 'switch' context", $operator);
Chris@13:                     throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
Chris@13:                 }
Chris@13: 
Chris@13:                 if ($node->num instanceof LNumber || $node->num instanceof DNumber) {
Chris@13:                     $num = $node->num->value;
Chris@13:                     if ($node->num instanceof DNumber || $num < 1) {
Chris@17:                         $msg = \sprintf("'%s' operator accepts only positive numbers", $operator);
Chris@13:                         throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
Chris@13:                     }
Chris@13: 
Chris@13:                     if ($num > $this->loopDepth) {
Chris@17:                         $msg = \sprintf("Cannot '%s' %d levels", $operator, $num);
Chris@13:                         throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
Chris@13:                     }
Chris@13:                 } elseif ($node->num) {
Chris@17:                     $msg = \sprintf("'%s' operator with non-constant operand is no longer supported", $operator);
Chris@13:                     throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
Chris@13:                 }
Chris@13:                 break;
Chris@13:         }
Chris@13:     }
Chris@13: 
Chris@13:     /**
Chris@13:      * @param Node $node
Chris@13:      */
Chris@13:     public function leaveNode(Node $node)
Chris@13:     {
Chris@13:         switch (true) {
Chris@13:             case $node instanceof Do_:
Chris@13:             case $node instanceof For_:
Chris@13:             case $node instanceof Foreach_:
Chris@13:             case $node instanceof Switch_:
Chris@13:             case $node instanceof While_:
Chris@13:                 $this->loopDepth--;
Chris@13:                 break;
Chris@13:         }
Chris@13:     }
Chris@13: }