Quelle  IUnknownImpl.h   Sprache: C

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* 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 mozilla_a11y_IUnknownImpl_h_
#define mozilla_a11y_IUnknownImpl_h_

#include <windows.h>
#undef CreateEvent  // thank you windows you're such a helper
#include "nsError.h"

// Avoid warning C4509 like "nonstandard extension used:
// 'AccessibleWrap::[acc_getName]' uses SEH and 'name' has destructor.
// At this point we're catching a crash which is of much greater
// importance than the missing dereference for the nsCOMPtr<>
#ifdef _MSC_VER
#  pragma warning(disable : 4509)
#endif

#if defined(__GNUC__) || defined(__clang__)
#  define ATTRIBUTE_UNUSED __attribute__((unused))
#else
#  define ATTRIBUTE_UNUSED
#endif

namespace mozilla {
namespace a11y {

class AutoRefCnt {
 public:
  AutoRefCnt() : mValue(0) {}

  ULONG operator++() { return ++mValue; }
  ULONG operator--() { return --mValue; }
  ULONG operator++(int) { return ++mValue; }
  ULONG operator--(int) { return --mValue; }

  operator ULONG() const { return mValue; }

 private:
  ULONG mValue;
};

}  // namespace a11y
}  // namespace mozilla

#define DECL_IUNKNOWN                                                        \
 public:                                                                     \
  virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, void**) override; \
  ULONG STDMETHODCALLTYPE AddRef() override {                                \
    MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt");                     \
    ++mRefCnt;                                                               \
    return mRefCnt;                                                          \
  }                                                                          \
  ULONG STDMETHODCALLTYPE Release() override {                               \
    MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release");                         \
    --mRefCnt;                                                               \
    if (mRefCnt) return mRefCnt;                                             \
                                                                             \
    delete this;                                                             \
    return 0;                                                                \
  }                                                                          \
                                                                             \
 private:                                                                    \
  mozilla::a11y::AutoRefCnt mRefCnt;                                         \
                                                                             \
 public:

#define DECL_IUNKNOWN_INHERITED \
 public:                        \
  virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, void**) override;

#define IMPL_IUNKNOWN_QUERY_HEAD(Class)                     \
  STDMETHODIMP                                              \
  Class::QueryInterface(REFIID aIID, void** aInstancePtr) { \
    if (!aInstancePtr) return E_INVALIDARG;                 \
    *aInstancePtr = nullptr;                                \
                                                            \
    HRESULT hr ATTRIBUTE_UNUSED = E_NOINTERFACE;

#define IMPL_IUNKNOWN_QUERY_TAIL \
  return hr;                     \
  }

#define IMPL_IUNKNOWN_QUERY_TAIL_AGGREGATED(Member)  \
  return Member->QueryInterface(aIID, aInstancePtr); \
  }

#define IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(BaseClass)   \
  return BaseClass::QueryInterface(aIID, aInstancePtr); \
  }

#define IMPL_IUNKNOWN_QUERY_IFACE(Iface)       \
  if (aIID == IID_##Iface) {                   \
    *aInstancePtr = static_cast<Iface*>(this); \
    AddRef();                                  \
    return S_OK;                               \
  }

#define IMPL_IUNKNOWN_QUERY_IFACE_AMBIGIOUS(Iface, aResolveIface)           \
  if (aIID == IID_##Iface) {                                                \
    *aInstancePtr = static_cast<Iface*>(static_cast<aResolveIface*>(this)); \
    AddRef();                                                               \
    return S_OK;                                                            \
  }

#define IMPL_IUNKNOWN_QUERY_CLASS(Class)          \
  hr = Class::QueryInterface(aIID, aInstancePtr); \
  if (SUCCEEDED(hr)) return hr;

#define IMPL_IUNKNOWN_QUERY_CLASS_COND(Class, Cond) \
  if (Cond) {                                       \
    hr = Class::QueryInterface(aIID, aInstancePtr); \
    if (SUCCEEDED(hr)) return hr;                   \
  }

#define IMPL_IUNKNOWN_QUERY_AGGR_COND(Member, Cond)  \
  if (Cond) {                                        \
    hr = Member->QueryInterface(aIID, aInstancePtr); \
    if (SUCCEEDED(hr)) return hr;                    \
  }

#define IMPL_IUNKNOWN1(Class, I1)      \
  IMPL_IUNKNOWN_QUERY_HEAD(Class)      \
  IMPL_IUNKNOWN_QUERY_IFACE(I1);       \
  IMPL_IUNKNOWN_QUERY_IFACE(IUnknown); \
  IMPL_IUNKNOWN_QUERY_TAIL

#define IMPL_IUNKNOWN2(Class, I1, I2)                \
  IMPL_IUNKNOWN_QUERY_HEAD(Class)                    \
  IMPL_IUNKNOWN_QUERY_IFACE(I1);                     \
  IMPL_IUNKNOWN_QUERY_IFACE(I2);                     \
  IMPL_IUNKNOWN_QUERY_IFACE_AMBIGIOUS(IUnknown, I1); \
  IMPL_IUNKNOWN_QUERY_TAIL

#define IMPL_IUNKNOWN_INHERITED1(Class, Super0, Super1) \
  IMPL_IUNKNOWN_QUERY_HEAD(Class)                       \
  IMPL_IUNKNOWN_QUERY_CLASS(Super1);                    \
  IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(Super0)

#define IMPL_IUNKNOWN_INHERITED2(Class, Super0, Super1, Super2) \
  IMPL_IUNKNOWN_QUERY_HEAD(Class)                               \
  IMPL_IUNKNOWN_QUERY_CLASS(Super1);                            \
  IMPL_IUNKNOWN_QUERY_CLASS(Super2);                            \
  IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(Super0)

/**
 * Overrides AddRef and Release to call a specific base class.
 * If you are inheriting a single class (e.g. to override some methods), you
 * shouldn't need to use this. However, if you are inheriting from a COM
 * implementation and also inheriting additional COM interfaces, you will need
 * to use this to specify which base implements reference counting.
 */
#define IMPL_IUNKNOWN_REFCOUNTING_INHERITED(BaseClass)                      \
 public:                                                                    \
  ULONG STDMETHODCALLTYPE AddRef() override { return BaseClass::AddRef(); } \
  ULONG STDMETHODCALLTYPE Release() override { return BaseClass::Release(); }

namespace mozilla {
namespace a11y {

/**
 * Converts nsresult to HRESULT.
 */
HRESULT GetHRESULT(nsresult aResult);

}  // namespace a11y
}  // namespace mozilla

#endif