feat: limit call stack size

2 files changed, 27 insertions, 0 deletions

diff --git a/src/Execution/Stack.php b/src/Execution/Stack.php
index 424f8c6..6d2a2aa 100644
--- a/src/Execution/Stack.php
+++ b/src/Execution/Stack.php
@@ -30,6 +30,9 @@ final class Stack
 
     public function pushFrame(Frame $frame): void
     {
+        if ($this->getCallStackLimit() <= count($this->frames)) {
+            throw new StackOverflowException();
+        }
         $this->push($frame);
         $this->frames[] = $frame;
         $this->currentFrame = $frame;
@@ -179,6 +182,11 @@ final class Stack
         return $this->currentFrame;
     }
 
+    public function getCallStackLimit(): int
+    {
+        return 1024;
+    }
+
     private function push(int|float|Ref|Frame|Label $entry): void
     {
         $this->entries[] = $entry;
diff --git a/src/Execution/StackOverflowException.php b/src/Execution/StackOverflowException.php
new file mode 100644
index 0000000..92991e2
--- /dev/null
+++ b/src/Execution/StackOverflowException.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsfisis\Waddiwasi\Execution;
+
+use RuntimeException;
+use Throwable;
+
+final class StackOverflowException extends RuntimeException
+{
+    public function __construct(
+        string $message = 'Stack overflow',
+        int $code = 0,
+        Throwable $previous = null,
+    ) {
+        parent::__construct($message, $code, $previous);
+    }
+}