1 files changed, 22 insertions, 0 deletions
diff --git a/xfa/fxfa/fm2js/cxfa_fmtojavascriptdepth.h b/xfa/fxfa/fm2js/cxfa_fmtojavascriptdepth.h
new file mode 100644
index 0000000000..14f87a68f5
--- /dev/null
+++ b/xfa/fxfa/fm2js/cxfa_fmtojavascriptdepth.h
@@ -0,0 +1,22 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef XFA_FXFA_FM2JS_CXFA_FMTOJAVASCRIPTDEPTH_H_
+#define XFA_FXFA_FM2JS_CXFA_FMTOJAVASCRIPTDEPTH_H_
+
+class CXFA_FMToJavaScriptDepth {
+ public:
+  CXFA_FMToJavaScriptDepth() { depth_++; }
+  ~CXFA_FMToJavaScriptDepth() { depth_--; }
+
+  bool IsWithinMaxDepth() const { return depth_ <= max_depth_; }
+
+  static void Reset();
+
+ private:
+  static unsigned long depth_;
+  static unsigned long max_depth_;
+};
+
+#endif  // XFA_FXFA_FM2JS_CXFA_FMTOJAVASCRIPTDEPTH_H_