michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* vim: set ts=8 sts=4 et sw=4 tw=99: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef xpcObjectHelper_h
michael@0: #define xpcObjectHelper_h
michael@0: 
michael@0: // Including 'windows.h' will #define GetClassInfo to something else.
michael@0: #ifdef XP_WIN
michael@0: #ifdef GetClassInfo
michael@0: #undef GetClassInfo
michael@0: #endif
michael@0: #endif
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: #include <stdint.h>
michael@0: #include "nsAutoPtr.h"
michael@0: #include "nsCOMPtr.h"
michael@0: #include "nsIClassInfo.h"
michael@0: #include "nsISupports.h"
michael@0: #include "nsIXPCScriptable.h"
michael@0: #include "nsWrapperCache.h"
michael@0: 
michael@0: class xpcObjectHelper
michael@0: {
michael@0: public:
michael@0:     xpcObjectHelper(nsISupports *aObject, nsWrapperCache *aCache = nullptr)
michael@0:       : mCanonical(nullptr)
michael@0:       , mObject(aObject)
michael@0:       , mCache(aCache)
michael@0:     {
michael@0:         if (!mCache) {
michael@0:             if (aObject)
michael@0:                 CallQueryInterface(aObject, &mCache);
michael@0:             else
michael@0:                 mCache = nullptr;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     nsISupports *Object()
michael@0:     {
michael@0:         return mObject;
michael@0:     }
michael@0: 
michael@0:     nsISupports *GetCanonical()
michael@0:     {
michael@0:         if (!mCanonical) {
michael@0:             mCanonicalStrong = do_QueryInterface(mObject);
michael@0:             mCanonical = mCanonicalStrong;
michael@0:         }
michael@0:         return mCanonical;
michael@0:     }
michael@0: 
michael@0:     already_AddRefed<nsISupports> forgetCanonical()
michael@0:     {
michael@0:         MOZ_ASSERT(mCanonical, "Huh, no canonical to forget?");
michael@0: 
michael@0:         if (!mCanonicalStrong)
michael@0:             mCanonicalStrong = mCanonical;
michael@0:         mCanonical = nullptr;
michael@0:         return mCanonicalStrong.forget();
michael@0:     }
michael@0: 
michael@0:     nsIClassInfo *GetClassInfo()
michael@0:     {
michael@0:         if (mXPCClassInfo)
michael@0:           return mXPCClassInfo;
michael@0:         if (!mClassInfo)
michael@0:             mClassInfo = do_QueryInterface(mObject);
michael@0:         return mClassInfo;
michael@0:     }
michael@0:     nsXPCClassInfo *GetXPCClassInfo()
michael@0:     {
michael@0:         if (!mXPCClassInfo) {
michael@0:             CallQueryInterface(mObject, getter_AddRefs(mXPCClassInfo));
michael@0:         }
michael@0:         return mXPCClassInfo;
michael@0:     }
michael@0: 
michael@0:     already_AddRefed<nsXPCClassInfo> forgetXPCClassInfo()
michael@0:     {
michael@0:         GetXPCClassInfo();
michael@0: 
michael@0:         return mXPCClassInfo.forget();
michael@0:     }
michael@0: 
michael@0:     // We assert that we can reach an nsIXPCScriptable somehow.
michael@0:     uint32_t GetScriptableFlags()
michael@0:     {
michael@0:         // Try getting an nsXPCClassInfo - this handles DOM scriptable helpers.
michael@0:         nsCOMPtr<nsIXPCScriptable> sinfo = GetXPCClassInfo();
michael@0: 
michael@0:         // If that didn't work, try just QI-ing. This handles BackstagePass.
michael@0:         if (!sinfo)
michael@0:             sinfo = do_QueryInterface(GetCanonical());
michael@0: 
michael@0:         // We should have something by now.
michael@0:         MOZ_ASSERT(sinfo);
michael@0: 
michael@0:         // Grab the flags.
michael@0:         return sinfo->GetScriptableFlags();
michael@0:     }
michael@0: 
michael@0:     nsWrapperCache *GetWrapperCache()
michael@0:     {
michael@0:         return mCache;
michael@0:     }
michael@0: 
michael@0: protected:
michael@0:     xpcObjectHelper(nsISupports *aObject, nsISupports *aCanonical,
michael@0:                     nsWrapperCache *aCache)
michael@0:       : mCanonical(aCanonical)
michael@0:       , mObject(aObject)
michael@0:       , mCache(aCache)
michael@0:     {
michael@0:         if (!mCache && aObject)
michael@0:             CallQueryInterface(aObject, &mCache);
michael@0:     }
michael@0: 
michael@0:     nsCOMPtr<nsISupports>    mCanonicalStrong;
michael@0:     nsISupports*             mCanonical;
michael@0: 
michael@0: private:
michael@0:     xpcObjectHelper(xpcObjectHelper& aOther) MOZ_DELETE;
michael@0: 
michael@0:     nsISupports*             mObject;
michael@0:     nsWrapperCache*          mCache;
michael@0:     nsCOMPtr<nsIClassInfo>   mClassInfo;
michael@0:     nsRefPtr<nsXPCClassInfo> mXPCClassInfo;
michael@0: };
michael@0: 
michael@0: #endif