dom/bindings/SpiderMonkeyInterface.h
author James Teh <jteh@mozilla.com>
Thu, 07 Mar 2019 18:10:13 +0000
changeset 520910 c26d4a8d43c4d0d6f6e13135b8f35924123fe99e
parent 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1527922: Ensure the Reload button is disabled when testing against blank tabs in the browser toolbar key nav tests. r=Gijs For a blank tab, the Reload button should be disabled. These tests depend on this. This seems to be true when setting the new tab page to blank in Firefox Options. However, when we open about:blank with BrowserTestUtils.withNewTab, this is unreliable. That is, sometimes the Reload button is enabled, sometimes it isn't. I don't understand why this happens. For the purposes of these tests, just force the Reload button to be disabled for new, blank tabs so we get consistent results. Differential Revision: https://phabricator.services.mozilla.com/D22449

/* -*- 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 */