1 files changed, 69 insertions, 0 deletions
diff --git a/js/public/Exception.h b/js/public/Exception.h
new file mode 100644
index 0000000000..f81f4780eb
--- /dev/null
+++ b/js/public/Exception.h
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef js_Exception_h
+#define js_Exception_h
+
+#include "mozilla/Attributes.h"
+
+#include "jspubtd.h"
+#include "js/RootingAPI.h"  // JS::{Handle,Rooted}
+#include "js/Value.h"       // JS::Value, JS::Handle<JS::Value>
+
+namespace JS {
+
+// This class encapsulates a (pending) exception and the corresponding optional
+// SavedFrame stack object captured when the pending exception was set
+// on the JSContext. This fuzzily correlates with a `throw` statement in JS,
+// although arbitrary JSAPI consumers or VM code may also set pending exceptions
+// via `JS_SetPendingException`.
+//
+// This is not the same stack as `e.stack` when `e` is an `Error` object.
+// (That would be JS::ExceptionStackOrNull).
+class MOZ_STACK_CLASS ExceptionStack {
+  Rooted<Value> exception_;
+  Rooted<JSObject*> stack_;
+
+  friend JS_PUBLIC_API bool GetPendingExceptionStack(
+      JSContext* cx, JS::ExceptionStack* exceptionStack);
+
+  void init(HandleValue exception, HandleObject stack) {
+    exception_ = exception;
+    stack_ = stack;
+  }
+
+ public:
+  explicit ExceptionStack(JSContext* cx) : exception_(cx), stack_(cx) {}
+
+  ExceptionStack(JSContext* cx, HandleValue exception, HandleObject stack)
+      : exception_(cx, exception), stack_(cx, stack) {}
+
+  HandleValue exception() const { return exception_; }
+
+  // |stack| can be null.
+  HandleObject stack() const { return stack_; }
+};
+
+// Get the current pending exception value and stack.
+// This function asserts that there is a pending exception.
+// If this function returns false, then retrieving the current pending exception
+// failed and might have been overwritten by a new exception.
+extern JS_PUBLIC_API bool GetPendingExceptionStack(
+    JSContext* cx, JS::ExceptionStack* exceptionStack);
+
+// Similar to GetPendingExceptionStack, but also clears the current
+// pending exception.
+extern JS_PUBLIC_API bool StealPendingExceptionStack(
+    JSContext* cx, JS::ExceptionStack* exceptionStack);
+
+// Set both the exception value and its associated stack on the context as
+// the current pending exception.
+extern JS_PUBLIC_API void SetPendingExceptionStack(
+    JSContext* cx, const JS::ExceptionStack& exceptionStack);
+
+}  // namespace JS
+
+#endif  // js_Exception_h