/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ /* vim: set ts=8 sts=4 et sw=4 tw=99: */ /* 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 xpcObjectHelper_h #define xpcObjectHelper_h // Including 'windows.h' will #define GetClassInfo to something else. #ifdef XP_WIN #ifdef GetClassInfo #undef GetClassInfo #endif #endif #include "mozilla/Attributes.h" #include <stdint.h> #include "nsCOMPtr.h" #include "nsIClassInfo.h" #include "nsISupports.h" #include "nsIXPCScriptable.h" #include "nsWrapperCache.h" class xpcObjectHelper { public: explicit xpcObjectHelper(nsISupports* aObject, nsWrapperCache* aCache = nullptr) : mCanonical(nullptr) , mObject(aObject) , mCache(aCache) { if (!mCache) { if (aObject) CallQueryInterface(aObject, &mCache); else mCache = nullptr; } } nsISupports* Object() { return mObject; } nsISupports* GetCanonical() { if (!mCanonical) { mCanonicalStrong = do_QueryInterface(mObject); mCanonical = mCanonicalStrong; } return mCanonical; } already_AddRefed<nsISupports> forgetCanonical() { MOZ_ASSERT(mCanonical, "Huh, no canonical to forget?"); if (!mCanonicalStrong) mCanonicalStrong = mCanonical; mCanonical = nullptr; return mCanonicalStrong.forget(); } nsIClassInfo* GetClassInfo() { if (mXPCClassInfo) return mXPCClassInfo; if (!mClassInfo) mClassInfo = do_QueryInterface(mObject); return mClassInfo; } nsXPCClassInfo* GetXPCClassInfo() { if (!mXPCClassInfo) { CallQueryInterface(mObject, getter_AddRefs(mXPCClassInfo)); } return mXPCClassInfo; } already_AddRefed<nsXPCClassInfo> forgetXPCClassInfo() { GetXPCClassInfo(); return mXPCClassInfo.forget(); } // We assert that we can reach an nsIXPCScriptable somehow. uint32_t GetScriptableFlags() { // Try getting an nsXPCClassInfo - this handles DOM scriptable helpers. nsCOMPtr<nsIXPCScriptable> sinfo = GetXPCClassInfo(); // If that didn't work, try just QI-ing. This handles BackstagePass. if (!sinfo) sinfo = do_QueryInterface(GetCanonical()); // We should have something by now. MOZ_ASSERT(sinfo); // Grab the flags. return sinfo->GetScriptableFlags(); } nsWrapperCache* GetWrapperCache() { return mCache; } protected: xpcObjectHelper(nsISupports* aObject, nsISupports* aCanonical, nsWrapperCache* aCache) : mCanonical(aCanonical) , mObject(aObject) , mCache(aCache) { if (!mCache && aObject) CallQueryInterface(aObject, &mCache); } nsCOMPtr<nsISupports> mCanonicalStrong; nsISupports* MOZ_UNSAFE_REF("xpcObjectHelper has been specifically optimized " "to avoid unnecessary AddRefs and Releases. " "(see bug 565742)") mCanonical; private: xpcObjectHelper(xpcObjectHelper& aOther) = delete; nsISupports* MOZ_UNSAFE_REF("xpcObjectHelper has been specifically optimized " "to avoid unnecessary AddRefs and Releases. " "(see bug 565742)") mObject; nsWrapperCache* mCache; nsCOMPtr<nsIClassInfo> mClassInfo; RefPtr<nsXPCClassInfo> mXPCClassInfo; }; #endif