Enable IAccessible2 for MinGW

MinGW 5.3 is able to compile the IAccessible2 classes. All that is needed
is some way to provide the missing IIDs, which is done via specialization
of a function template (similar to the MinGW's __uuidof operator).

[ChangeLog][Windows][Accessibility] MinGW builds now support IAccessible2.

Change-Id: I218a4b89c81b54aa96f7c743544388631ca9a53e
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

src/3rdparty/iaccessible2/generated/x86/ia2_api_all.h

@@ -16,7 +16,9 @@
 */
 /* @@MIDL_FILE_HEADING(  ) */
 
-#pragma warning( disable: 4049 )  /* more than 64k source lines */
+#ifdef _MSC_VER
+#  pragma warning( disable: 4049 )  /* more than 64k source lines */
+#endif
 
 
 /* verify that the <rpcndr.h> version is high enough to compile this file*/

src/3rdparty/iaccessible2/generated/x86/ia2_api_all_i.c

@@ -18,7 +18,9 @@
 */
 /* @@MIDL_FILE_HEADING(  ) */
 
-#pragma warning( disable: 4049 )  /* more than 64k source lines */
+#ifdef _MSC_VER
+#  pragma warning( disable: 4049 )  /* more than 64k source lines */
+#endif
 
 
 #ifdef __cplusplus
@@ -65,7 +67,7 @@ typedef IID CLSID;
 #define MIDL_DEFINE_GUID(type,name,l,w1,w2,b1,b2,b3,b4,b5,b6,b7,b8) \
         const type name = {l,w1,w2,{b1,b2,b3,b4,b5,b6,b7,b8}}
 
-#endif !_MIDL_USE_GUIDDEF_
+#endif // !_MIDL_USE_GUIDDEF_
 
 MIDL_DEFINE_GUID(IID, IID_IAccessibleRelation,0x7CDF86EE,0xC3DA,0x496a,0xBD,0xA4,0x28,0x1B,0x33,0x6E,0x1F,0xDC);
 

src/plugins/platforms/windows/accessible/accessible.pri

@@ -6,13 +6,14 @@ HEADERS += \
     $$PWD/qwindowsaccessibility.h \
     $$PWD/comutils.h
 
-SOURCES += $$PWD/qwindowsmsaaaccessible.cpp
-HEADERS += $$PWD/qwindowsmsaaaccessible.h
+SOURCES += \
+    $$PWD/qwindowsmsaaaccessible.cpp \
+    $$PWD/iaccessible2.cpp
 
-!mingw: {
-    SOURCES += $$PWD/iaccessible2.cpp
-    HEADERS += $$PWD/iaccessible2.h
-    include(../../../../3rdparty/iaccessible2/iaccessible2.pri)
-}
+HEADERS += \
+    $$PWD/qwindowsmsaaaccessible.h \
+    $$PWD/iaccessible2.h
+
+include(../../../../3rdparty/iaccessible2/iaccessible2.pri)
 
 mingw: LIBS *= -luuid

src/plugins/platforms/windows/accessible/iaccessible2.h

@@ -52,6 +52,12 @@
 
 QT_BEGIN_NAMESPACE
 
+#ifdef Q_CC_MINGW
+// MinGW's __uuidof operator does not work for the Accessible2 interfaces
+template <>
+IID qUuidOf<IAccessibleComponent>() { return IID_IAccessibleComponent; }
+#endif // Q_CC_MINGW
+
 class QWindowsIA2Accessible : public QWindowsMsaaAccessible,
         public IAccessibleAction,
         public IAccessibleComponent,
@@ -258,6 +264,19 @@ private:
 /**************************************************************\
  *                     AccessibleApplication                  *
  **************************************************************/
+
+#ifdef Q_CC_MINGW
+// MinGW's __uuidof operator does not work for the IAccessible2 interfaces
+template <>
+IID qUuidOf<IAccessibleApplication>() { return IID_IAccessibleApplication; }
+
+template <>
+IID qUuidOf<IAccessible2>() { return IID_IAccessible2; }
+
+template <>
+IID qUuidOf<IAccessibleRelation>() { return IID_IAccessibleRelation; }
+#endif // Q_CC_MINGW
+
 class AccessibleApplication : public QWindowsComBase<IAccessibleApplication>
 {
 public:
@@ -277,6 +296,9 @@ public:
 /**************************************************************\
  *                     AccessibleRelation                      *
  **************************************************************/
+
+
+
 class AccessibleRelation : public QWindowsComBase<IAccessibleRelation>
 {
 public:

src/plugins/platforms/windows/accessible/qwindowsaccessibility.cpp

@@ -56,11 +56,7 @@
 #include <QtFontDatabaseSupport/private/qwindowsfontdatabase_p.h> // registry helper
 
 #include "qwindowsaccessibility.h"
-#ifdef Q_CC_MINGW
-#   include "qwindowsmsaaaccessible.h"
-#else
-#   include "iaccessible2.h"
-#endif
+#include "iaccessible2.h"
 #include "comutils.h"
 
 #include <oleacc.h>
@@ -198,11 +194,7 @@ IAccessible *QWindowsAccessibility::wrap(QAccessibleInterface *acc)
     if (!QAccessible::uniqueId(acc))
         QAccessible::registerAccessibleInterface(acc);
 
-# ifdef Q_CC_MINGW
-    QWindowsMsaaAccessible *wacc = new QWindowsMsaaAccessible(acc);
-# else
     QWindowsIA2Accessible *wacc = new QWindowsIA2Accessible(acc);
-# endif
     IAccessible *iacc = 0;
     wacc->QueryInterface(IID_IAccessible, reinterpret_cast<void **>(&iacc));
     return iacc;

src/plugins/platforms/windows/accessible/qwindowsmsaaaccessible.cpp

@@ -156,7 +156,7 @@ void accessibleDebugClientCalls_helper(const char* funcName, const QAccessibleIn
 HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::QueryInterface(REFIID id, LPVOID *iface)
 {
     *iface = nullptr;
-    const bool result = qWindowsComQueryUnknownInterfaceMulti<AccessibleBase>(this, id, iface)
+    const bool result = qWindowsComQueryUnknownInterfaceMulti<IAccessible2>(this, id, iface)
         || qWindowsComQueryInterface<IDispatch>(this, id, iface)
         || qWindowsComQueryInterface<IAccessible>(this, id, iface)
         || qWindowsComQueryInterface<IOleWindow>(this, id, iface);
@@ -1172,7 +1172,6 @@ const char *QWindowsAccessibleGuid::iidToString(const GUID &id)
         result = "IID_IOleWindow";
     else if (id == IID_IServiceProvider)
         result = "IID_IServiceProvider";
-#ifndef Q_CC_MINGW
     else if (id == IID_IAccessible2)
         result = "IID_IAccessible2";
     else if (id == IID_IAccessibleAction)
@@ -1201,7 +1200,6 @@ const char *QWindowsAccessibleGuid::iidToString(const GUID &id)
         result = "IID_IAccessibleText";
     else if (id == IID_IAccessibleValue)
         result = "IID_IAccessibleValue";
-#endif // !Q_CC_MINGW
     return result;
 }
 

src/plugins/platforms/windows/accessible/qwindowsmsaaaccessible.h

@@ -46,14 +46,8 @@
 #include <QtCore/qt_windows.h>
 #include <QtCore/qsharedpointer.h>
 #include <QtGui/qaccessible.h>
-#ifndef Q_CC_MINGW
-# include <oleacc.h>
-# include "ia2_api_all.h"   // IAccessible2 inherits from IAccessible
-#else
-    // MinGW
-# include <basetyps.h>
-# include <oleacc.h>
-#endif
+#include <oleacc.h>
+#include "ia2_api_all.h"   // IAccessible2 inherits from IAccessible
 
 QT_BEGIN_NAMESPACE
 
@@ -88,13 +82,7 @@ QDebug operator<<(QDebug d, const QWindowsAccessibleGuid &aguid);
  *                     QWindowsAccessible                     *
  **************************************************************/
 
-#ifndef Q_CC_MINGW
-typedef IAccessible2 AccessibleBase;
-#else
-typedef IAccessible AccessibleBase;
-#endif
-
-class QWindowsMsaaAccessible : public AccessibleBase, public IOleWindow
+class QWindowsMsaaAccessible : public IAccessible2, public IOleWindow
 {
 public:
     QWindowsMsaaAccessible(QAccessibleInterface *a)

src/plugins/platforms/windows/qwindowscombase.h

@@ -46,11 +46,17 @@
 
 QT_BEGIN_NAMESPACE
 
+// The __uuidof operator of MinGW does not work for all interfaces (for example,
+// IAccessible2). Specializations of this function can be provides to work
+// around this.
+template <class DesiredInterface>
+static IID qUuidOf() { return __uuidof(DesiredInterface); }
+
 // Helper for implementing IUnknown::QueryInterface.
 template <class DesiredInterface, class Derived>
 bool qWindowsComQueryInterface(Derived *d, REFIID id, LPVOID *iface)
 {
-    if (id == __uuidof(DesiredInterface)) {
+    if (id == qUuidOf<DesiredInterface>()) {
         *iface = static_cast<DesiredInterface *>(d);
         d->AddRef();
         return true;