1 files changed, 57 insertions, 0 deletions
diff --git a/fxjs/cjs_result.h b/fxjs/cjs_result.h
new file mode 100644
index 0000000000..dc65d18c73
--- /dev/null
+++ b/fxjs/cjs_result.h
@@ -0,0 +1,57 @@
+// 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.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#ifndef FXJS_CJS_RESULT_H_
+#define FXJS_CJS_RESULT_H_
+
+#include "fxjs/cfxjs_engine.h"
+#include "fxjs/js_resources.h"
+#include "third_party/base/optional.h"
+
+class CJS_Result {
+ public:
+  // Wrap constructors with static methods so we can apply WARN_UNUSED_RESULT,
+  // otherwise we can't catch places where someone mistakenly writes:
+  //
+  //     if (error)
+  //       CJS_Result(JS_ERROR_CODE);
+  //
+  // instead of
+  //
+  //     if (error)
+  //       return CJS_Result(JS_ERROR_CODE);
+  //
+  static CJS_Result Success() WARN_UNUSED_RESULT { return CJS_Result(); }
+  static CJS_Result Success(v8::Local<v8::Value> value) WARN_UNUSED_RESULT {
+    return CJS_Result(value);
+  }
+  static CJS_Result Failure(const WideString& str) WARN_UNUSED_RESULT {
+    return CJS_Result(str);
+  }
+  static CJS_Result Failure(JSMessage id) WARN_UNUSED_RESULT {
+    return CJS_Result(id);
+  }
+
+  CJS_Result(const CJS_Result&);
+  ~CJS_Result();
+
+  bool HasError() const { return error_.has_value(); }
+  WideString Error() const { return error_.value(); }
+
+  bool HasReturn() const { return !return_.IsEmpty(); }
+  v8::Local<v8::Value> Return() const { return return_; }
+
+ private:
+  CJS_Result();                               // Successful but empty return.
+  explicit CJS_Result(v8::Local<v8::Value>);  // Successful return with value.
+  explicit CJS_Result(const WideString&);     // Error with custom message.
+  explicit CJS_Result(JSMessage id);          // Error with stock message.
+
+  Optional<WideString> error_;
+  v8::Local<v8::Value> return_;
+};
+
+#endif  // FXJS_CJS_RESULT_H_