--- /dev/null
+<?php
+
+/*
+ * This file is part of Psy Shell.
+ *
+ * (c) 2012-2017 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Psy\CodeCleaner;
+
+use PhpParser\Node;
+use PhpParser\Node\Scalar\DNumber;
+use PhpParser\Node\Scalar\LNumber;
+use PhpParser\Node\Stmt\Break_;
+use PhpParser\Node\Stmt\Continue_;
+use PhpParser\Node\Stmt\Do_;
+use PhpParser\Node\Stmt\For_;
+use PhpParser\Node\Stmt\Foreach_;
+use PhpParser\Node\Stmt\Switch_;
+use PhpParser\Node\Stmt\While_;
+use Psy\Exception\FatalErrorException;
+
+/**
+ * The loop context pass handles invalid `break` and `continue` statements.
+ */
+class LoopContextPass extends CodeCleanerPass
+{
+ private $isPHP54;
+ private $loopDepth;
+
+ public function __construct()
+ {
+ $this->isPHP54 = version_compare(PHP_VERSION, '5.4.0', '>=');
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function beforeTraverse(array $nodes)
+ {
+ $this->loopDepth = 0;
+ }
+
+ /**
+ * @throws FatalErrorException if the node is a break or continue in a non-loop or switch context
+ * @throws FatalErrorException if the node is trying to break out of more nested structures than exist
+ * @throws FatalErrorException if the node is a break or continue and has a non-numeric argument
+ * @throws FatalErrorException if the node is a break or continue and has an argument less than 1
+ *
+ * @param Node $node
+ */
+ public function enterNode(Node $node)
+ {
+ switch (true) {
+ case $node instanceof Do_:
+ case $node instanceof For_:
+ case $node instanceof Foreach_:
+ case $node instanceof Switch_:
+ case $node instanceof While_:
+ $this->loopDepth++;
+ break;
+
+ case $node instanceof Break_:
+ case $node instanceof Continue_:
+ $operator = $node instanceof Break_ ? 'break' : 'continue';
+
+ if ($this->loopDepth === 0) {
+ $msg = sprintf("'%s' not in the 'loop' or 'switch' context", $operator);
+ throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
+ }
+
+ if ($node->num instanceof LNumber || $node->num instanceof DNumber) {
+ $num = $node->num->value;
+ if ($this->isPHP54 && ($node->num instanceof DNumber || $num < 1)) {
+ $msg = sprintf("'%s' operator accepts only positive numbers", $operator);
+ throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
+ }
+
+ if ($num > $this->loopDepth) {
+ $msg = sprintf("Cannot '%s' %d levels", $operator, $num);
+ throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
+ }
+ } elseif ($node->num && $this->isPHP54) {
+ $msg = sprintf("'%s' operator with non-constant operand is no longer supported", $operator);
+ throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
+ }
+ break;
+ }
+ }
+
+ /**
+ * @param Node $node
+ */
+ public function leaveNode(Node $node)
+ {
+ switch (true) {
+ case $node instanceof Do_:
+ case $node instanceof For_:
+ case $node instanceof Foreach_:
+ case $node instanceof Switch_:
+ case $node instanceof While_:
+ $this->loopDepth--;
+ break;
+ }
+ }
+}