xpcObjectHelper.h (1829B)
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */ 3 /* This Source Code Form is subject to the terms of the Mozilla Public 4 * License, v. 2.0. If a copy of the MPL was not distributed with this 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 6 7 #ifndef xpcObjectHelper_h 8 #define xpcObjectHelper_h 9 10 // Including 'windows.h' will #define GetClassInfo to something else. 11 #ifdef XP_WIN 12 # ifdef GetClassInfo 13 # undef GetClassInfo 14 # endif 15 #endif 16 17 #include "mozilla/Attributes.h" 18 #include <stdint.h> 19 #include "nsCOMPtr.h" 20 #include "nsIClassInfo.h" 21 #include "nsISupports.h" 22 #include "nsIXPCScriptable.h" 23 #include "nsWrapperCache.h" 24 25 class xpcObjectHelper { 26 public: 27 explicit xpcObjectHelper(nsISupports* aObject, 28 nsWrapperCache* aCache = nullptr) 29 : mObject(aObject), mCache(aCache) { 30 if (!mCache && aObject) { 31 CallQueryInterface(aObject, &mCache); 32 } 33 } 34 35 nsISupports* Object() { return mObject; } 36 37 nsIClassInfo* GetClassInfo() { 38 if (!mClassInfo) { 39 mClassInfo = do_QueryInterface(mObject); 40 } 41 return mClassInfo; 42 } 43 44 // We assert that we can reach an nsIXPCScriptable somehow. 45 uint32_t GetScriptableFlags() { 46 nsCOMPtr<nsIXPCScriptable> sinfo = do_QueryInterface(mObject); 47 48 // We should have something by now. 49 MOZ_ASSERT(sinfo); 50 51 // Grab the flags. 52 return sinfo->GetScriptableFlags(); 53 } 54 55 nsWrapperCache* GetWrapperCache() { return mCache; } 56 57 private: 58 xpcObjectHelper(xpcObjectHelper& aOther) = delete; 59 60 nsISupports* MOZ_UNSAFE_REF( 61 "xpcObjectHelper has been specifically optimized " 62 "to avoid unnecessary AddRefs and Releases. " 63 "(see bug 565742)") mObject; 64 nsWrapperCache* mCache; 65 nsCOMPtr<nsIClassInfo> mClassInfo; 66 }; 67 68 #endif