зеркало из https://github.com/mozilla/gecko-dev.git
143 строки
3.8 KiB
C++
143 строки
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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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 mozilla_mscom_WeakRef_h
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#define mozilla_mscom_WeakRef_h
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#include <guiddef.h>
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#include <unknwn.h>
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#include "mozilla/Assertions.h"
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#include "mozilla/Atomics.h"
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#include "mozilla/RefPtr.h"
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#include "nsISupportsImpl.h"
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/**
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* Thread-safe weak references for COM that works pre-Windows 8 and do not
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* require WinRT.
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*/
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namespace mozilla {
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namespace mscom {
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struct IWeakReferenceSource;
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class WeakReferenceSupport;
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namespace detail {
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class SharedRef final {
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public:
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explicit SharedRef(WeakReferenceSupport* aSupport);
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void Lock();
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void Unlock();
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HRESULT ToStrongRef(IWeakReferenceSource** aOutStringReference);
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HRESULT Resolve(REFIID aIid, void** aOutStrongReference);
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void Clear();
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NS_INLINE_DECL_THREADSAFE_REFCOUNTING(SharedRef)
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SharedRef(const SharedRef&) = delete;
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SharedRef(SharedRef&&) = delete;
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SharedRef& operator=(const SharedRef&) = delete;
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SharedRef& operator=(SharedRef&&) = delete;
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private:
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~SharedRef();
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private:
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CRITICAL_SECTION mCS;
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WeakReferenceSupport* mSupport;
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};
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} // namespace detail
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// {F841AEFA-064C-49A4-B73D-EBD14A90F012}
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DEFINE_GUID(IID_IWeakReference, 0xf841aefa, 0x64c, 0x49a4, 0xb7, 0x3d, 0xeb,
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0xd1, 0x4a, 0x90, 0xf0, 0x12);
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struct IWeakReference : public IUnknown {
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virtual STDMETHODIMP ToStrongRef(
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IWeakReferenceSource** aOutStrongReference) = 0;
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virtual STDMETHODIMP Resolve(REFIID aIid, void** aOutStrongReference) = 0;
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};
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// {87611F0C-9BBB-4F78-9D43-CAC5AD432CA1}
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DEFINE_GUID(IID_IWeakReferenceSource, 0x87611f0c, 0x9bbb, 0x4f78, 0x9d, 0x43,
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0xca, 0xc5, 0xad, 0x43, 0x2c, 0xa1);
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struct IWeakReferenceSource : public IUnknown {
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virtual STDMETHODIMP GetWeakReference(IWeakReference** aOutWeakRef) = 0;
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};
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class WeakRef;
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class WeakReferenceSupport : public IWeakReferenceSource {
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public:
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enum class Flags { eNone = 0, eDestroyOnMainThread = 1 };
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// IUnknown
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STDMETHODIMP QueryInterface(REFIID riid, void** ppv) override;
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STDMETHODIMP_(ULONG) AddRef() override;
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STDMETHODIMP_(ULONG) Release() override;
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// IWeakReferenceSource
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STDMETHODIMP GetWeakReference(IWeakReference** aOutWeakRef) override;
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protected:
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explicit WeakReferenceSupport(Flags aFlags);
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virtual ~WeakReferenceSupport() = default;
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virtual HRESULT WeakRefQueryInterface(REFIID aIid,
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IUnknown** aOutInterface) = 0;
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class MOZ_RAII StabilizeRefCount final {
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public:
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explicit StabilizeRefCount(WeakReferenceSupport& aObject);
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~StabilizeRefCount();
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StabilizeRefCount(const StabilizeRefCount&) = delete;
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StabilizeRefCount(StabilizeRefCount&&) = delete;
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StabilizeRefCount& operator=(const StabilizeRefCount&) = delete;
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StabilizeRefCount& operator=(StabilizeRefCount&&) = delete;
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private:
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WeakReferenceSupport& mObject;
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};
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friend class StabilizeRefCount;
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private:
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RefPtr<detail::SharedRef> mSharedRef;
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ULONG mRefCnt;
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Flags mFlags;
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};
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class WeakRef final : public IWeakReference {
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public:
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// IUnknown
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STDMETHODIMP QueryInterface(REFIID riid, void** ppv) override;
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STDMETHODIMP_(ULONG) AddRef() override;
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STDMETHODIMP_(ULONG) Release() override;
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// IWeakReference
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STDMETHODIMP ToStrongRef(IWeakReferenceSource** aOutStrongReference) override;
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STDMETHODIMP Resolve(REFIID aIid, void** aOutStrongReference) override;
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explicit WeakRef(RefPtr<detail::SharedRef>& aSharedRef);
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private:
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~WeakRef() = default;
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Atomic<ULONG> mRefCnt;
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RefPtr<detail::SharedRef> mSharedRef;
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};
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} // namespace mscom
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} // namespace mozilla
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#endif // mozilla_mscom_WeakRef_h
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