139 lines
3.7 KiB
C++
139 lines
3.7 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* vim: set ts=8 sts=4 et sw=4 tw=99: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef xpcObjectHelper_h
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#define xpcObjectHelper_h
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// Including 'windows.h' will #define GetClassInfo to something else.
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#ifdef XP_WIN
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#ifdef GetClassInfo
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#undef GetClassInfo
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#endif
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#endif
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#include "mozilla/Attributes.h"
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#include <stdint.h>
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#include "nsAutoPtr.h"
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#include "nsCOMPtr.h"
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#include "nsIClassInfo.h"
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#include "nsISupports.h"
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#include "nsIXPCScriptable.h"
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#include "nsWrapperCache.h"
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class xpcObjectHelper
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{
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public:
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explicit xpcObjectHelper(nsISupports* aObject, nsWrapperCache* aCache = nullptr)
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: mCanonical(nullptr)
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, mObject(aObject)
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, mCache(aCache)
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{
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if (!mCache) {
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if (aObject)
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CallQueryInterface(aObject, &mCache);
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else
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mCache = nullptr;
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}
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}
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nsISupports* Object()
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{
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return mObject;
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}
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nsISupports* GetCanonical()
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{
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if (!mCanonical) {
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mCanonicalStrong = do_QueryInterface(mObject);
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mCanonical = mCanonicalStrong;
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}
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return mCanonical;
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}
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already_AddRefed<nsISupports> forgetCanonical()
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{
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MOZ_ASSERT(mCanonical, "Huh, no canonical to forget?");
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if (!mCanonicalStrong)
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mCanonicalStrong = mCanonical;
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mCanonical = nullptr;
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return mCanonicalStrong.forget();
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}
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nsIClassInfo* GetClassInfo()
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{
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if (mXPCClassInfo)
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return mXPCClassInfo;
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if (!mClassInfo)
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mClassInfo = do_QueryInterface(mObject);
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return mClassInfo;
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}
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nsXPCClassInfo* GetXPCClassInfo()
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{
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if (!mXPCClassInfo) {
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CallQueryInterface(mObject, getter_AddRefs(mXPCClassInfo));
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}
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return mXPCClassInfo;
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}
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already_AddRefed<nsXPCClassInfo> forgetXPCClassInfo()
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{
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GetXPCClassInfo();
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return mXPCClassInfo.forget();
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}
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// We assert that we can reach an nsIXPCScriptable somehow.
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uint32_t GetScriptableFlags()
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{
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// Try getting an nsXPCClassInfo - this handles DOM scriptable helpers.
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nsCOMPtr<nsIXPCScriptable> sinfo = GetXPCClassInfo();
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// If that didn't work, try just QI-ing. This handles BackstagePass.
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if (!sinfo)
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sinfo = do_QueryInterface(GetCanonical());
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// We should have something by now.
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MOZ_ASSERT(sinfo);
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// Grab the flags.
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return sinfo->GetScriptableFlags();
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}
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nsWrapperCache* GetWrapperCache()
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{
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return mCache;
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}
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protected:
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xpcObjectHelper(nsISupports* aObject, nsISupports* aCanonical,
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nsWrapperCache* aCache)
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: mCanonical(aCanonical)
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, mObject(aObject)
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, mCache(aCache)
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{
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if (!mCache && aObject)
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CallQueryInterface(aObject, &mCache);
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}
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nsCOMPtr<nsISupports> mCanonicalStrong;
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nsISupports* MOZ_UNSAFE_REF("xpcObjectHelper has been specifically optimized "
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"to avoid unnecessary AddRefs and Releases. "
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"(see bug 565742)") mCanonical;
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private:
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xpcObjectHelper(xpcObjectHelper& aOther) = delete;
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nsISupports* MOZ_UNSAFE_REF("xpcObjectHelper has been specifically optimized "
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"to avoid unnecessary AddRefs and Releases. "
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"(see bug 565742)") mObject;
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nsWrapperCache* mCache;
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nsCOMPtr<nsIClassInfo> mClassInfo;
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RefPtr<nsXPCClassInfo> mXPCClassInfo;
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};
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#endif
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