1 files changed, 144 insertions, 0 deletions
diff --git a/dom/bindings/SpiderMonkeyInterface.h b/dom/bindings/SpiderMonkeyInterface.h
new file mode 100644
index 0000000000..f852afddaf
--- /dev/null
+++ b/dom/bindings/SpiderMonkeyInterface.h
@@ -0,0 +1,144 @@
+/* -*- 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 mozilla_dom_SpiderMonkeyInterface_h
+#define mozilla_dom_SpiderMonkeyInterface_h
+
+#include "jsapi.h"
+#include "jsfriendapi.h"
+#include "js/TracingAPI.h"
+
+namespace mozilla {
+namespace dom {
+
+/*
+ * Class that just handles the JSObject storage and tracing for spidermonkey
+ * interfaces
+ */
+struct SpiderMonkeyInterfaceObjectStorage
+{
+protected:
+  JSObject* mImplObj;
+  JSObject* mWrappedObj;
+
+  SpiderMonkeyInterfaceObjectStorage()
+    : mImplObj(nullptr),
+      mWrappedObj(nullptr)
+  {
+  }
+
+  SpiderMonkeyInterfaceObjectStorage(SpiderMonkeyInterfaceObjectStorage&& aOther)
+    : mImplObj(aOther.mImplObj),
+      mWrappedObj(aOther.mWrappedObj)
+  {
+    aOther.mImplObj = nullptr;
+    aOther.mWrappedObj = nullptr;
+  }
+
+public:
+  inline void TraceSelf(JSTracer* trc)
+  {
+    JS::UnsafeTraceRoot(trc, &mImplObj, "SpiderMonkeyInterfaceObjectStorage.mImplObj");
+    JS::UnsafeTraceRoot(trc, &mWrappedObj, "SpiderMonkeyInterfaceObjectStorage.mWrappedObj");
+  }
+
+  inline bool inited() const
+  {
+    return !!mImplObj;
+  }
+
+  inline bool WrapIntoNewCompartment(JSContext* cx)
+  {
+    return JS_WrapObject(cx,
+      JS::MutableHandle<JSObject*>::fromMarkedLocation(&mWrappedObj));
+  }
+
+  inline JSObject *Obj() const
+  {
+    MOZ_ASSERT(inited());
+    return mWrappedObj;
+  }
+
+private:
+  SpiderMonkeyInterfaceObjectStorage(const SpiderMonkeyInterfaceObjectStorage&) = delete;
+};
+
+// A class for rooting an existing SpiderMonkey Interface struct
+template<typename InterfaceType>
+class MOZ_RAII SpiderMonkeyInterfaceRooter : private JS::CustomAutoRooter
+{
+public:
+  template <typename CX>
+  SpiderMonkeyInterfaceRooter(const CX& cx,
+                              InterfaceType* aInterface MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
+      mInterface(aInterface)
+  {
+  }
+
+  virtual void trace(JSTracer* trc) override
+  {
+    mInterface->TraceSelf(trc);
+  }
+
+private:
+  SpiderMonkeyInterfaceObjectStorage* const mInterface;
+};
+
+// And a specialization for dealing with nullable SpiderMonkey interfaces
+template<typename Inner> struct Nullable;
+template<typename InterfaceType>
+class MOZ_RAII SpiderMonkeyInterfaceRooter<Nullable<InterfaceType>> :
+    private JS::CustomAutoRooter
+{
+public:
+  template <typename CX>
+  SpiderMonkeyInterfaceRooter(const CX& cx,
+                              Nullable<InterfaceType>* aInterface MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
+      mInterface(aInterface)
+  {
+  }
+
+  virtual void trace(JSTracer* trc) override
+  {
+    if (!mInterface->IsNull()) {
+      mInterface->Value().TraceSelf(trc);
+    }
+  }
+
+private:
+  Nullable<InterfaceType>* const mInterface;
+};
+
+// Class for easily setting up a rooted SpiderMonkey interface object on the
+// stack
+template<typename InterfaceType>
+class MOZ_RAII RootedSpiderMonkeyInterface final : public InterfaceType,
+                                                   private SpiderMonkeyInterfaceRooter<InterfaceType>
+{
+public:
+  template <typename CX>
+  explicit RootedSpiderMonkeyInterface(const CX& cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : InterfaceType(),
+      SpiderMonkeyInterfaceRooter<InterfaceType>(cx, this
+                                                 MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
+  {
+  }
+
+  template <typename CX>
+  RootedSpiderMonkeyInterface(const CX& cx, JSObject* obj MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : InterfaceType(obj),
+      SpiderMonkeyInterfaceRooter<InterfaceType>(cx, this
+                                                 MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
+  {
+  }
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_SpiderMonkeyInterface_h */