Fix DirectShow COM class hierarchy

Remove the class DirectShowObject. Move the ref counting code
to a macro COM_REF_MIXIN that is used for the classes that are
actually instantiated.

Fix warnings:
common/directshowpin.h(56,5):  warning: 'reinterpret_cast' from class 'DirectShowPin *' to its base at non-zero offset 'IUnknown *' behaves differently from 'static_cast' [-Wreinterpret-base-class]
    DIRECTSHOW_OBJECT
    ^~~~~~~~~~~~~~~~~
common/directshowobject.h(69,33):  note: expanded from macro 'DIRECTSHOW_OBJECT'
            return GetInterface(reinterpret_cast<IUnknown*>(this), ppv); \
                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
common/directshowpin.h(56,5):  note: use 'static_cast' to adjust the pointer correctly while upcasting

Task-number: QTBUG-63512
Task-number: QTBUG-64157
Change-Id: Ibef143d675cd169b78fe46ff5a0c83f6e3434487
Reviewed-by: VaL Doroshchuk <valentyn.doroshchuk@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

13 files changed, 79 insertions, 205 deletions

diff --git a/src/plugins/directshow/common/common.pri b/src/plugins/directshow/common/common.pri
index 06f8582ac..43acff8a5 100644
--- a/src/plugins/directshow/common/common.pri
+++ b/src/plugins/directshow/common/common.pri
@@ -20,7 +20,6 @@ SOURCES += \
     $$PWD/directshoweventloop.cpp \
     $$PWD/directshowmediatype.cpp \
     $$PWD/directshowmediatypeenum.cpp \
-    $$PWD/directshowobject.cpp \
     $$PWD/directshowpin.cpp \
     $$PWD/directshowpinenum.cpp \
     $$PWD/directshowvideobuffer.cpp \
diff --git a/src/plugins/directshow/common/directshowbasefilter.cpp b/src/plugins/directshow/common/directshowbasefilter.cpp
index 342f0c271..1e45eea51 100644
--- a/src/plugins/directshow/common/directshowbasefilter.cpp
+++ b/src/plugins/directshow/common/directshowbasefilter.cpp
@@ -61,17 +61,6 @@ DirectShowBaseFilter::~DirectShowBaseFilter()
     }
 }
 
-HRESULT DirectShowBaseFilter::getInterface(REFIID riid, void **ppvObject)
-{
-    if (riid == IID_IPersist
-            || riid == IID_IMediaFilter
-            || riid == IID_IBaseFilter) {
-        return GetInterface(static_cast<IBaseFilter *>(this), ppvObject);
-    } else {
-        return DirectShowObject::getInterface(riid, ppvObject);
-    }
-}
-
 HRESULT DirectShowBaseFilter::GetClassID(CLSID *pClassID)
 {
     *pClassID = CLSID_NULL;
diff --git a/src/plugins/directshow/common/directshowbasefilter.h b/src/plugins/directshow/common/directshowbasefilter.h
index 9a2f44567..47a390d26 100644
--- a/src/plugins/directshow/common/directshowbasefilter.h
+++ b/src/plugins/directshow/common/directshowbasefilter.h
@@ -44,11 +44,8 @@
 
 QT_BEGIN_NAMESPACE
 
-class DirectShowBaseFilter : public DirectShowObject
-                           , public IBaseFilter
+class DirectShowBaseFilter : public IBaseFilter
 {
-    DIRECTSHOW_OBJECT
-
 public:
     DirectShowBaseFilter();
     virtual ~DirectShowBaseFilter();
@@ -58,9 +55,6 @@ public:
 
     virtual QList<DirectShowPin *> pins() = 0;
 
-    // DirectShowObject
-    HRESULT getInterface(const IID &riid, void **ppvObject);
-
     // IPersist
     STDMETHODIMP GetClassID(CLSID *pClassID);
 
diff --git a/src/plugins/directshow/common/directshowmediatypeenum.cpp b/src/plugins/directshow/common/directshowmediatypeenum.cpp
index 8fbdf7dea..a6afcd5f1 100644
--- a/src/plugins/directshow/common/directshowmediatypeenum.cpp
+++ b/src/plugins/directshow/common/directshowmediatypeenum.cpp
@@ -62,13 +62,18 @@ DirectShowMediaTypeEnum::~DirectShowMediaTypeEnum()
         m_pin->Release();
 }
 
-HRESULT DirectShowMediaTypeEnum::getInterface(REFIID riid, void **ppvObject)
+HRESULT DirectShowMediaTypeEnum::QueryInterface(REFIID riid, void **ppv)
 {
-    if (riid == IID_IEnumMediaTypes) {
-        return GetInterface(static_cast<IEnumMediaTypes *>(this), ppvObject);
-    } else {
-        return DirectShowObject::getInterface(riid, ppvObject);
-    }
+    if (ppv == nullptr)
+        return E_POINTER;
+    if (riid == IID_IUnknown)
+        *ppv = static_cast<IUnknown *>(this);
+    else if (riid == IID_IEnumMediaTypes)
+        *ppv = static_cast<IEnumMediaTypes *>(this);
+    else
+        return E_NOINTERFACE;
+    AddRef();
+    return S_OK;
 }
 
 HRESULT DirectShowMediaTypeEnum::Next(ULONG cMediaTypes, AM_MEDIA_TYPE **ppMediaTypes, ULONG *pcFetched)
diff --git a/src/plugins/directshow/common/directshowmediatypeenum.h b/src/plugins/directshow/common/directshowmediatypeenum.h
index 9b058fc5b..ee2568338 100644
--- a/src/plugins/directshow/common/directshowmediatypeenum.h
+++ b/src/plugins/directshow/common/directshowmediatypeenum.h
@@ -48,18 +48,15 @@ QT_BEGIN_NAMESPACE
 class DirectShowPin;
 class DirectShowMediaType;
 
-class DirectShowMediaTypeEnum : public DirectShowObject
-                              , public IEnumMediaTypes
+class DirectShowMediaTypeEnum : public IEnumMediaTypes
 {
-    DIRECTSHOW_OBJECT
-
+    COM_REF_MIXIN
 public:
     DirectShowMediaTypeEnum(DirectShowPin *pin);
     DirectShowMediaTypeEnum(const QList<DirectShowMediaType> &types);
-    ~DirectShowMediaTypeEnum();
+    virtual ~DirectShowMediaTypeEnum();
 
-    // DirectShowObject
-    HRESULT getInterface(REFIID riid, void **ppvObject);
+    STDMETHODIMP QueryInterface(REFIID riid, void **ppv) override;
 
     // IEnumMediaTypes
     STDMETHODIMP Next(ULONG cMediaTypes, AM_MEDIA_TYPE **ppMediaTypes, ULONG *pcFetched);
diff --git a/src/plugins/directshow/common/directshowobject.cpp b/src/plugins/directshow/common/directshowobject.cpp
deleted file mode 100644
index db1817a8d..000000000
--- a/src/plugins/directshow/common/directshowobject.cpp
+++ /dev/null
@@ -1,86 +0,0 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** Commercial License Usage
-** Licensees holding valid commercial Qt licenses may use this file in
-** accordance with the commercial license agreement provided with the
-** Software or, alternatively, in accordance with the terms contained in
-** a written agreement between you and The Qt Company. For licensing terms
-** and conditions see https://www.qt.io/terms-conditions. For further
-** information use the contact form at https://www.qt.io/contact-us.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
-
-#include "directshowobject.h"
-
-QT_BEGIN_NAMESPACE
-
-DirectShowObject::DirectShowObject()
-    : m_ref(1)
-{
-}
-
-DirectShowObject::~DirectShowObject()
-{
-    Q_ASSERT(m_ref == 0);
-}
-
-HRESULT DirectShowObject::getInterface(const IID &riid, void **ppvObject)
-{
-    Q_UNUSED(riid)
-    *ppvObject = NULL;
-    return E_NOINTERFACE;
-}
-
-ULONG DirectShowObject::ref()
-{
-    return InterlockedIncrement(&m_ref);
-}
-
-ULONG DirectShowObject::unref()
-{
-    ULONG ref = InterlockedDecrement(&m_ref);
-    if (ref == 0)
-        delete this;
-
-    return ref;
-}
-
-HRESULT GetInterface(IUnknown *pUnk, void **ppv)
-{
-    if (!ppv)
-        return E_POINTER;
-
-    *ppv = pUnk;
-    pUnk->AddRef();
-
-    return S_OK;
-}
-
-QT_END_NAMESPACE
diff --git a/src/plugins/directshow/common/directshowobject.h b/src/plugins/directshow/common/directshowobject.h
index cfac16f61..5a8c05a3e 100644
--- a/src/plugins/directshow/common/directshowobject.h
+++ b/src/plugins/directshow/common/directshowobject.h
@@ -44,38 +44,20 @@
 
 QT_BEGIN_NAMESPACE
 
-class DirectShowObject
-{
-public:
-    DirectShowObject();
-    virtual ~DirectShowObject();
-
-    virtual HRESULT getInterface(REFIID riid, void **ppvObject);
-    ULONG ref();
-    ULONG unref();
-
-private:
-    Q_DISABLE_COPY(DirectShowObject)
-
-    volatile LONG m_ref;
-};
-
-HRESULT GetInterface(IUnknown *pUnk, void **ppv);
-
-#define DIRECTSHOW_OBJECT \
-public: \
-    STDMETHODIMP QueryInterface(REFIID riid, void **ppv) {          \
-        if (riid == IID_IUnknown)                                   \
-            return GetInterface(reinterpret_cast<IUnknown*>(this), ppv); \
-        else                                                        \
-            return getInterface(riid, ppv);                         \
-    };                                                              \
-    STDMETHODIMP_(ULONG) AddRef() {                                 \
-        return ref();                                               \
-    };                                                              \
-    STDMETHODIMP_(ULONG) Release() {                                \
-        return unref();                                             \
-    };
+#define COM_REF_MIXIN \
+    volatile ULONG m_ref = 1;                              \
+public:                                                    \
+    STDMETHODIMP_(ULONG) AddRef() override                 \
+    {                                                      \
+        return InterlockedIncrement(&m_ref);               \
+    }                                                      \
+    STDMETHODIMP_(ULONG) Release() override                \
+    {                                                      \
+        const ULONG ref = InterlockedDecrement(&m_ref);    \
+        if (ref == 0)                                      \
+            delete this;                                   \
+        return ref;                                        \
+    }
 
 QT_END_NAMESPACE
 
diff --git a/src/plugins/directshow/common/directshowpin.cpp b/src/plugins/directshow/common/directshowpin.cpp
index b49c3f8a4..65b54b8e9 100644
--- a/src/plugins/directshow/common/directshowpin.cpp
+++ b/src/plugins/directshow/common/directshowpin.cpp
@@ -61,16 +61,6 @@ DirectShowPin::~DirectShowPin()
 
 }
 
-HRESULT DirectShowPin::getInterface(const IID &riid, void **ppvObject)
-{
-    if (riid == IID_IPin)
-        return GetInterface(static_cast<IPin*>(this), ppvObject);
-    else
-        return DirectShowObject::getInterface(riid, ppvObject);
-}
-
-
-
 HRESULT DirectShowPin::Connect(IPin *pReceivePin, const AM_MEDIA_TYPE *pmt)
 {
     if (!pReceivePin)
@@ -526,14 +516,6 @@ DirectShowInputPin::~DirectShowInputPin()
 
 }
 
-HRESULT DirectShowInputPin::getInterface(const IID &riid, void **ppvObject)
-{
-    if (riid == IID_IMemInputPin)
-        return GetInterface(static_cast<IMemInputPin*>(this), ppvObject);
-    else
-        return DirectShowPin::getInterface(riid, ppvObject);
-}
-
 HRESULT DirectShowInputPin::connectionEnded()
 {
     if (m_allocator) {
diff --git a/src/plugins/directshow/common/directshowpin.h b/src/plugins/directshow/common/directshowpin.h
index 97e808384..ee2cbc58d 100644
--- a/src/plugins/directshow/common/directshowpin.h
+++ b/src/plugins/directshow/common/directshowpin.h
@@ -50,11 +50,8 @@ QT_BEGIN_NAMESPACE
 
 class DirectShowBaseFilter;
 
-class DirectShowPin : public DirectShowObject
-                    , public IPin
+class DirectShowPin : public IPin
 {
-    DIRECTSHOW_OBJECT
-
 public:
     virtual ~DirectShowPin();
 
@@ -70,9 +67,6 @@ public:
 
     virtual HRESULT setActive(bool active);
 
-    // DirectShowObject
-    HRESULT getInterface(REFIID riid, void **ppvObject);
-
     // IPin
     STDMETHODIMP Connect(IPin *pReceivePin, const AM_MEDIA_TYPE *pmt);
     STDMETHODIMP ReceiveConnection(IPin *pConnector, const AM_MEDIA_TYPE *pmt);
@@ -120,8 +114,6 @@ private:
 
 class DirectShowOutputPin : public DirectShowPin
 {
-    DIRECTSHOW_OBJECT
-
 public:
     virtual ~DirectShowOutputPin();
 
@@ -147,16 +139,11 @@ private:
 class DirectShowInputPin : public DirectShowPin
                          , public IMemInputPin
 {
-    DIRECTSHOW_OBJECT
-
 public:
     virtual ~DirectShowInputPin();
 
     const AM_SAMPLE2_PROPERTIES *currentSampleProperties() const { return &m_sampleProperties; }
 
-    // DirectShowObject
-    HRESULT getInterface(REFIID riid, void **ppvObject);
-
     // DirectShowPin
     HRESULT connectionEnded();
     HRESULT setActive(bool active);
diff --git a/src/plugins/directshow/common/directshowpinenum.cpp b/src/plugins/directshow/common/directshowpinenum.cpp
index 910bba77d..e0ab58d19 100644
--- a/src/plugins/directshow/common/directshowpinenum.cpp
+++ b/src/plugins/directshow/common/directshowpinenum.cpp
@@ -71,13 +71,18 @@ DirectShowPinEnum::~DirectShowPinEnum()
         m_filter->Release();
 }
 
-HRESULT DirectShowPinEnum::getInterface(REFIID riid, void **ppvObject)
+HRESULT DirectShowPinEnum::QueryInterface(REFIID riid, void **ppv)
 {
-    if (riid == IID_IEnumPins) {
-        return GetInterface(static_cast<IEnumPins *>(this), ppvObject);
-    } else {
-        return DirectShowObject::getInterface(riid, ppvObject);
-    }
+    if (ppv == nullptr)
+        return E_POINTER;
+    if (riid == IID_IUnknown)
+        *ppv = static_cast<IUnknown *>(this);
+    else if (riid == IID_IEnumPins)
+        *ppv = static_cast<IEnumPins *>(this);
+    else
+        return E_NOINTERFACE;
+    AddRef();
+    return S_OK;
 }
 
 HRESULT DirectShowPinEnum::Next(ULONG cPins, IPin **ppPins, ULONG *pcFetched)
diff --git a/src/plugins/directshow/common/directshowpinenum.h b/src/plugins/directshow/common/directshowpinenum.h
index 77214e376..e1baa00c2 100644
--- a/src/plugins/directshow/common/directshowpinenum.h
+++ b/src/plugins/directshow/common/directshowpinenum.h
@@ -49,18 +49,15 @@ QT_BEGIN_NAMESPACE
 
 class DirectShowBaseFilter;
 
-class DirectShowPinEnum : public DirectShowObject
-                        , public IEnumPins
+class DirectShowPinEnum : public IEnumPins
 {
-    DIRECTSHOW_OBJECT
-
+    COM_REF_MIXIN
 public:
     DirectShowPinEnum(DirectShowBaseFilter *filter);
     DirectShowPinEnum(const QList<IPin *> &pins);
-    ~DirectShowPinEnum();
+    virtual ~DirectShowPinEnum();
 
-    // DirectShowObject
-    HRESULT getInterface(REFIID riid, void **ppvObject);
+    STDMETHODIMP QueryInterface(REFIID riid, void **ppv) override;
 
     // IEnumPins
     STDMETHODIMP Next(ULONG cPins, IPin **ppPins, ULONG *pcFetched);
diff --git a/src/plugins/directshow/player/videosurfacefilter.cpp b/src/plugins/directshow/player/videosurfacefilter.cpp
index 656cd5a7c..0b1c97a74 100644
--- a/src/plugins/directshow/player/videosurfacefilter.cpp
+++ b/src/plugins/directshow/player/videosurfacefilter.cpp
@@ -59,12 +59,12 @@ DEFINE_GUID(CLSID_VideoSurfaceFilter,
 
 class VideoSurfaceInputPin : public DirectShowInputPin
 {
-    DIRECTSHOW_OBJECT
-
+    COM_REF_MIXIN
 public:
     VideoSurfaceInputPin(VideoSurfaceFilter *filter);
 
-    // DirectShowPin
+    STDMETHODIMP QueryInterface(REFIID riid, void **ppv) override;
+
     bool isMediaTypeSupported(const AM_MEDIA_TYPE *type) override;
     bool setMediaType(const AM_MEDIA_TYPE *type) override;
 
@@ -92,6 +92,22 @@ VideoSurfaceInputPin::VideoSurfaceInputPin(VideoSurfaceFilter *filter)
 {
 }
 
+HRESULT VideoSurfaceInputPin::QueryInterface(REFIID riid, void **ppv)
+{
+    if (ppv == nullptr)
+        return E_POINTER;
+    if (riid == IID_IUnknown)
+        *ppv = static_cast<IUnknown *>(static_cast<DirectShowPin *>(this));
+    else if (riid == IID_IPin)
+        *ppv = static_cast<IPin *>(this);
+    else if (riid == IID_IMemInputPin)
+        *ppv =static_cast<IMemInputPin*>(this);
+    else
+        return E_NOINTERFACE;
+    AddRef();
+    return S_OK;
+}
+
 bool VideoSurfaceInputPin::isMediaTypeSupported(const AM_MEDIA_TYPE *type)
 {
     return m_videoSurfaceFilter->isMediaTypeSupported(type);
@@ -237,12 +253,20 @@ VideoSurfaceFilter::~VideoSurfaceFilter()
     CloseHandle(m_renderEvent);
 }
 
-HRESULT VideoSurfaceFilter::getInterface(const IID &riid, void **ppvObject)
+HRESULT VideoSurfaceFilter::QueryInterface(REFIID riid, void **ppv)
 {
-    if (riid == IID_IAMFilterMiscFlags)
-        return GetInterface(static_cast<IAMFilterMiscFlags*>(this), ppvObject);
+    if (ppv == nullptr)
+        return E_POINTER;
+    if (riid == IID_IUnknown)
+        *ppv = static_cast<IUnknown *>(static_cast<DirectShowBaseFilter *>(this));
+    else if (riid == IID_IPersist || riid == IID_IMediaFilter || riid == IID_IBaseFilter)
+        *ppv = static_cast<IBaseFilter *>(this);
+    else if (riid == IID_IAMFilterMiscFlags)
+        *ppv = static_cast<IAMFilterMiscFlags *>(this);
     else
-        return DirectShowBaseFilter::getInterface(riid, ppvObject);
+        return E_NOINTERFACE;
+    AddRef();
+    return S_OK;
 }
 
 QList<DirectShowPin *> VideoSurfaceFilter::pins()
diff --git a/src/plugins/directshow/player/videosurfacefilter.h b/src/plugins/directshow/player/videosurfacefilter.h
index ad253d564..43f8cc534 100644
--- a/src/plugins/directshow/player/videosurfacefilter.h
+++ b/src/plugins/directshow/player/videosurfacefilter.h
@@ -60,13 +60,12 @@ class VideoSurfaceFilter : public QObject
                          , public IAMFilterMiscFlags
 {
     Q_OBJECT
-    DIRECTSHOW_OBJECT
+    COM_REF_MIXIN
 public:
     VideoSurfaceFilter(QAbstractVideoSurface *surface, DirectShowEventLoop *loop, QObject *parent = 0);
     ~VideoSurfaceFilter();
 
-    // DirectShowObject
-    HRESULT getInterface(REFIID riid, void **ppvObject);
+    STDMETHODIMP QueryInterface(REFIID riid, void **ppv) override;
 
     // DirectShowBaseFilter
     QList<DirectShowPin *> pins();