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>

2 files changed, 33 insertions, 10 deletions

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();