Clean up windows accessibility backend

What was done:

 * Removed headers in src/gui/accessible/windows/apisupport: as of
   v13.1.0, MinGW supports most of the definitions in these headers.
   Including uiautomation.h should be enough.

 * Removed the QWindowsUiaWrapper class: it's not meant to be extended
   or itself instantiated, is an "ultra-thin" layer (it even preserves
   the "all-caps" Win types of function args), and is in effect only a
   MinGW-bound "kludge". Instead of this class, use the UI Automation
   API directly, with the assumption that it's available and fully
   functional, as specified in the MS docs. Any gaps between this
   assumption and what is delivered by MinGW are bridged with specific
   (and explicit) temporary "kludges".

 * Implemented said specific "kludges" in qwindowsuiautomation. For
   Windows builds, the header just includes uiautomation.h, and the
   .cpp is empty. For MinGW, the header contains definitions still
   missing from uiautomation.h, and the .cpp implements functions
   of the UI Automation core library through imports from the
   uiautomationcore DLL.

 * Windows plugins (and tst_qaccessibility): use the UI Automation API
   definitions directly, instead of the "ultra-thin" wrapper.

 * Windows plugin builds: use uiautomationcore library, if found.

What's intended:

 * Unburden Gui of the Windows UI Automation COM interfaces and other
   definitions that are copied in the uia*.h headers.

 * Make the Windows plugins independent of MinGW shortcomings.

 * Remove the QWindowsUiaWrapper class that essentially only hides these
   shortcomings and the "kludge" code needed to overcome them.

 * As MinGW adds further support to the UI Automation API over time,
   make it noticeable which workarounds are no longer needed. The
   current approach of hiding "kludges" in a wrapper class will also
   hide the fact that they're no longer needed, if/when that time comes.

Change-Id: I0070636817d5de81d0b106e9179e2d0442362e2a
Reviewed-by: Wladimir Leuschner <wladimir.leuschner@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

9 files changed, 185 insertions, 22 deletions

diff --git a/src/plugins/platforms/direct2d/CMakeLists.txt b/src/plugins/platforms/direct2d/CMakeLists.txt
index fe4a237aff..271104b71e 100644
--- a/src/plugins/platforms/direct2d/CMakeLists.txt
+++ b/src/plugins/platforms/direct2d/CMakeLists.txt
@@ -189,6 +189,7 @@ endif()
 
 qt_internal_extend_target(QWindowsDirect2DIntegrationPlugin CONDITION QT_FEATURE_accessibility
     SOURCES
+        ../windows/uiautomation/qwindowsuiautomation.cpp ../windows/uiautomation/qwindowsuiautomation.h
         ../windows/uiautomation/qwindowsuiaaccessibility.cpp ../windows/uiautomation/qwindowsuiaaccessibility.h
         ../windows/uiautomation/qwindowsuiabaseprovider.cpp ../windows/uiautomation/qwindowsuiabaseprovider.h
         ../windows/uiautomation/qwindowsuiaexpandcollapseprovider.cpp ../windows/uiautomation/qwindowsuiaexpandcollapseprovider.h
@@ -210,6 +211,16 @@ qt_internal_extend_target(QWindowsDirect2DIntegrationPlugin CONDITION QT_FEATURE
         ../windows/uiautomation/qwindowsuiawindowprovider.cpp ../windows/uiautomation/qwindowsuiawindowprovider.h
 )
 
+if(QT_FEATURE_accessibility)
+    find_library(UI_AUTOMATION_LIBRARY uiautomationcore)
+    if(UI_AUTOMATION_LIBRARY)
+        qt_internal_extend_target(QWindowsDirect2DIntegrationPlugin
+            LIBRARIES
+                ${UI_AUTOMATION_LIBRARY}
+        )
+    endif()
+endif()
+
 qt_internal_extend_target(QWindowsDirect2DIntegrationPlugin CONDITION MINGW AND QT_FEATURE_accessibility
     LIBRARIES
         uuid
diff --git a/src/plugins/platforms/windows/CMakeLists.txt b/src/plugins/platforms/windows/CMakeLists.txt
index ea119bfb1e..fb73b70c29 100644
--- a/src/plugins/platforms/windows/CMakeLists.txt
+++ b/src/plugins/platforms/windows/CMakeLists.txt
@@ -176,6 +176,7 @@ endif()
 
 qt_internal_extend_target(QWindowsIntegrationPlugin CONDITION QT_FEATURE_accessibility
     SOURCES
+        uiautomation/qwindowsuiautomation.cpp uiautomation/qwindowsuiautomation.h
         uiautomation/qwindowsuiaaccessibility.cpp uiautomation/qwindowsuiaaccessibility.h
         uiautomation/qwindowsuiabaseprovider.cpp uiautomation/qwindowsuiabaseprovider.h
         uiautomation/qwindowsuiaexpandcollapseprovider.cpp uiautomation/qwindowsuiaexpandcollapseprovider.h
@@ -197,6 +198,16 @@ qt_internal_extend_target(QWindowsIntegrationPlugin CONDITION QT_FEATURE_accessi
         uiautomation/qwindowsuiawindowprovider.cpp uiautomation/qwindowsuiawindowprovider.h
 )
 
+if(QT_FEATURE_accessibility)
+    find_library(UI_AUTOMATION_LIBRARY uiautomationcore)
+    if(UI_AUTOMATION_LIBRARY)
+        qt_internal_extend_target(QWindowsIntegrationPlugin
+            LIBRARIES
+                ${UI_AUTOMATION_LIBRARY}
+        )
+    endif()
+endif()
+
 qt_internal_extend_target(QWindowsIntegrationPlugin CONDITION MINGW AND QT_FEATURE_accessibility
     LIBRARIES
         uuid
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp
index 586afeef57..1abb412ccd 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp
@@ -5,6 +5,7 @@
 #if QT_CONFIG(accessibility)
 
 #include "qwindowsuiaaccessibility.h"
+#include "qwindowsuiautomation.h"
 #include "qwindowsuiamainprovider.h"
 #include "qwindowsuiautils.h"
 
@@ -14,7 +15,6 @@
 #include <QtGui/private/qguiapplication_p.h>
 #include <QtCore/qt_windows.h>
 #include <qpa/qplatformintegration.h>
-#include <QtGui/private/qwindowsuiawrapper_p.h>
 
 #include <QtCore/private/qwinregistry_p.h>
 
@@ -47,7 +47,7 @@ bool QWindowsUiaAccessibility::handleWmGetObject(HWND hwnd, WPARAM wParam, LPARA
     if (QWindow *window = QWindowsContext::instance()->findWindow(hwnd)) {
         if (QAccessibleInterface *accessible = window->accessibleRoot()) {
             QWindowsUiaMainProvider *provider = QWindowsUiaMainProvider::providerForAccessible(accessible);
-            *lResult = QWindowsUiaWrapper::instance()->returnRawElementProvider(hwnd, wParam, lParam, provider);
+            *lResult = UiaReturnRawElementProvider(hwnd, wParam, lParam, provider);
             return true;
         }
     }
@@ -122,12 +122,8 @@ void QWindowsUiaAccessibility::notifyAccessibilityUpdate(QAccessibleEvent *event
     if (!isActive() || !accessible || !accessible->isValid())
         return;
 
-    // Ensures QWindowsUiaWrapper is properly initialized.
-    if (!QWindowsUiaWrapper::instance()->ready())
-        return;
-
     // No need to do anything when nobody is listening.
-    if (!QWindowsUiaWrapper::instance()->clientsAreListening())
+    if (!UiaClientsAreListening())
         return;
 
     switch (event->type()) {
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.h
index 1813bb4d89..2e8ee585da 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.h
@@ -7,6 +7,7 @@
 #include <QtGui/qtguiglobal.h>
 #if QT_CONFIG(accessibility)
 
+#include <QtCore/qt_windows.h>
 #include "qwindowscontext.h"
 #include <qpa/qplatformaccessibility.h>
 
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h
index 445d71587a..032679ab10 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h
@@ -10,7 +10,7 @@
 #include <QtGui/qaccessible.h>
 #include <QtCore/qpointer.h>
 
-#include <QtGui/private/qwindowsuiawrapper_p.h>
+#include "qwindowsuiautomation.h"
 #include <QtCore/private/qcomobject_p.h>
 
 QT_BEGIN_NAMESPACE
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
index e171f4d452..29cd1c6237 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
@@ -81,7 +81,7 @@ void QWindowsUiaMainProvider::notifyFocusChange(QAccessibleEvent *event)
                 accessible = child;
         }
         if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible))
-            QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_AutomationFocusChangedEventId);
+            UiaRaiseAutomationEvent(provider, UIA_AutomationFocusChangedEventId);
     }
 }
 
@@ -98,7 +98,7 @@ void QWindowsUiaMainProvider::notifyStateChange(QAccessibleStateChangeEvent *eve
                     if (accessible->state().checked)
                         toggleState = accessible->state().checkStateMixed ? ToggleState_Indeterminate : ToggleState_On;
                     setVariantI4(toggleState, &newVal);
-                    QWindowsUiaWrapper::instance()->raiseAutomationPropertyChangedEvent(provider, UIA_ToggleToggleStatePropertyId, oldVal, newVal);
+                    UiaRaiseAutomationPropertyChangedEvent(provider, UIA_ToggleToggleStatePropertyId, oldVal, newVal);
                 }
             }
         }
@@ -107,13 +107,13 @@ void QWindowsUiaMainProvider::notifyStateChange(QAccessibleStateChangeEvent *eve
                 // Notifies window opened/closed.
                 if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
                     if (accessible->state().active) {
-                        QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_Window_WindowOpenedEventId);
+                        UiaRaiseAutomationEvent(provider, UIA_Window_WindowOpenedEventId);
                         if (QAccessibleInterface *focused = accessible->focusChild()) {
                             if (QWindowsUiaMainProvider *focusedProvider = providerForAccessible(focused))
-                                QWindowsUiaWrapper::instance()->raiseAutomationEvent(focusedProvider, UIA_AutomationFocusChangedEventId);
+                                UiaRaiseAutomationEvent(focusedProvider, UIA_AutomationFocusChangedEventId);
                         }
                     } else {
-                        QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_Window_WindowClosedEventId);
+                        UiaRaiseAutomationEvent(provider, UIA_Window_WindowClosedEventId);
                     }
                 }
             }
@@ -146,7 +146,7 @@ void QWindowsUiaMainProvider::notifyValueChange(QAccessibleValueChangeEvent *eve
                 VARIANT oldVal, newVal;
                 clearVariant(&oldVal);
                 setVariantString(event->value().toString(), &newVal);
-                QWindowsUiaWrapper::instance()->raiseAutomationPropertyChangedEvent(provider, UIA_ValueValuePropertyId, oldVal, newVal);
+                UiaRaiseAutomationPropertyChangedEvent(provider, UIA_ValueValuePropertyId, oldVal, newVal);
             }
         } else if (QAccessibleValueInterface *valueInterface = accessible->valueInterface()) {
             if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
@@ -154,7 +154,7 @@ void QWindowsUiaMainProvider::notifyValueChange(QAccessibleValueChangeEvent *eve
                 VARIANT oldVal, newVal;
                 clearVariant(&oldVal);
                 setVariantDouble(valueInterface->currentValue().toDouble(), &newVal);
-                QWindowsUiaWrapper::instance()->raiseAutomationPropertyChangedEvent(provider, UIA_RangeValueValuePropertyId, oldVal, newVal);
+                UiaRaiseAutomationPropertyChangedEvent(provider, UIA_RangeValueValuePropertyId, oldVal, newVal);
             }
         }
     }
@@ -170,7 +170,7 @@ void QWindowsUiaMainProvider::notifyNameChange(QAccessibleEvent *event)
                 VARIANT oldVal, newVal;
                 clearVariant(&oldVal);
                 setVariantString(accessible->text(QAccessible::Name), &newVal);
-                QWindowsUiaWrapper::instance()->raiseAutomationPropertyChangedEvent(provider, UIA_NamePropertyId, oldVal, newVal);
+                UiaRaiseAutomationPropertyChangedEvent(provider, UIA_NamePropertyId, oldVal, newVal);
                 ::SysFreeString(newVal.bstrVal);
             }
         }
@@ -181,7 +181,7 @@ void QWindowsUiaMainProvider::notifySelectionChange(QAccessibleEvent *event)
 {
     if (QAccessibleInterface *accessible = event->accessibleInterface()) {
         if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
-            QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_SelectionItem_ElementSelectedEventId);
+            UiaRaiseAutomationEvent(provider, UIA_SelectionItem_ElementSelectedEventId);
         }
     }
 }
@@ -193,13 +193,13 @@ void QWindowsUiaMainProvider::notifyTextChange(QAccessibleEvent *event)
         if (accessible->textInterface()) {
             if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
                 if (event->type() == QAccessible::TextSelectionChanged) {
-                    QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_Text_TextSelectionChangedEventId);
+                    UiaRaiseAutomationEvent(provider, UIA_Text_TextSelectionChangedEventId);
                 } else if (event->type() == QAccessible::TextCaretMoved) {
                     if (!accessible->state().readOnly) {
-                        QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_Text_TextSelectionChangedEventId);
+                        UiaRaiseAutomationEvent(provider, UIA_Text_TextSelectionChangedEventId);
                     }
                 } else {
-                    QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_Text_TextChangedEventId);
+                    UiaRaiseAutomationEvent(provider, UIA_Text_TextChangedEventId);
                 }
             }
         }
@@ -538,7 +538,7 @@ HRESULT QWindowsUiaMainProvider::get_HostRawElementProvider(IRawElementProviderS
     // Returns a host provider only for controls associated with a native window handle. Others should return NULL.
     if (QAccessibleInterface *accessible = accessibleInterface()) {
         if (HWND hwnd = hwndForAccessible(accessible)) {
-            return QWindowsUiaWrapper::instance()->hostProviderFromHwnd(hwnd, pRetVal);
+            return UiaHostProviderFromHwnd(hwnd, pRetVal);
         }
     }
     return S_OK;
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiautils.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiautils.h
index 8fe8b1c6d7..bf90211cec 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiautils.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiautils.h
@@ -12,7 +12,7 @@
 #include <QtGui/qaccessible.h>
 #include <QtGui/qwindow.h>
 #include <QtCore/qrect.h>
-#include <QtGui/private/qwindowsuiawrapper_p.h>
+#include "qwindowsuiautomation.h"
 
 QT_BEGIN_NAMESPACE
 
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiautomation.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiautomation.cpp
new file mode 100644
index 0000000000..1593a07202
--- /dev/null
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiautomation.cpp
@@ -0,0 +1,74 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include <QtGui/qtguiglobal.h>
+#if QT_CONFIG(accessibility)
+
+#include "qwindowsuiautomation.h"
+
+#if defined(__MINGW32__) || defined(__MINGW64__)
+
+template<typename T, typename... TArg>
+struct winapi_func
+{
+    using func_t = T(WINAPI*)(TArg...);
+    const func_t func;
+    const T error_value;
+#ifdef __GNUC__
+#   pragma GCC diagnostic ignored "-Wcast-function-type"
+#endif
+    winapi_func(const char *lib_name, const char *func_name, func_t func_proto,
+        T error_value = T(__HRESULT_FROM_WIN32(ERROR_PROC_NOT_FOUND))) :
+        func(reinterpret_cast<func_t>(GetProcAddress(LoadLibraryA(lib_name), func_name))),
+        error_value(error_value)
+    {
+        std::ignore = func_proto;
+    }
+#ifdef __GNUC__
+#   pragma GCC diagnostic pop
+#endif
+    T invoke(TArg... arg)
+    {
+        if (!func)
+            return error_value;
+        return func(arg...);
+    }
+};
+
+#define FN(fn) #fn,fn
+
+BOOL WINAPI UiaClientsAreListening()
+{
+    static auto func = winapi_func("uiautomationcore", FN(UiaClientsAreListening), BOOL(false));
+    return func.invoke();
+}
+
+LRESULT WINAPI UiaReturnRawElementProvider(
+    HWND hwnd, WPARAM wParam, LPARAM lParam, IRawElementProviderSimple *el)
+{
+    static auto func = winapi_func("uiautomationcore", FN(UiaReturnRawElementProvider));
+    return func.invoke(hwnd, wParam, lParam, el);
+}
+
+HRESULT WINAPI UiaHostProviderFromHwnd(HWND hwnd, IRawElementProviderSimple **ppProvider)
+{
+    static auto func = winapi_func("uiautomationcore", FN(UiaHostProviderFromHwnd));
+    return func.invoke(hwnd, ppProvider);
+}
+
+HRESULT WINAPI UiaRaiseAutomationPropertyChangedEvent(
+    IRawElementProviderSimple *pProvider, PROPERTYID id, VARIANT oldValue, VARIANT newValue)
+{
+    static auto func = winapi_func("uiautomationcore", FN(UiaRaiseAutomationPropertyChangedEvent));
+    return func.invoke(pProvider, id, oldValue, newValue);
+}
+
+HRESULT WINAPI UiaRaiseAutomationEvent(IRawElementProviderSimple *pProvider, EVENTID id)
+{
+    static auto func = winapi_func("uiautomationcore", FN(UiaRaiseAutomationEvent));
+    return func.invoke(pProvider, id);
+}
+
+#endif // defined(__MINGW32__) || defined(__MINGW64__)
+
+#endif // QT_CONFIG(accessibility)
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiautomation.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiautomation.h
new file mode 100644
index 0000000000..a192b9b0fb
--- /dev/null
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiautomation.h
@@ -0,0 +1,70 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QWINDOWSUIAUTOMATION_H
+#define QWINDOWSUIAUTOMATION_H
+
+#include <QtGui/qtguiglobal.h>
+#if QT_CONFIG(accessibility)
+
+#include <uiautomation.h>
+
+#if defined(__MINGW32__) || defined(__MINGW64__)
+
+#define UIA_SelectionPattern2Id                  10034
+#define UIA_IsReadOnlyAttributeId                40015
+#define UIA_StrikethroughStyleAttributeId        40026
+#define UIA_CaretPositionAttributeId             40038
+
+enum CaretPosition {
+    CaretPosition_Unknown           = 0,
+    CaretPosition_EndOfLine         = 1,
+    CaretPosition_BeginningOfLine   = 2
+};
+
+enum TextDecorationLineStyle {
+    TextDecorationLineStyle_None = 0,
+    TextDecorationLineStyle_Single = 1,
+    TextDecorationLineStyle_WordsOnly = 2,
+    TextDecorationLineStyle_Double = 3,
+    TextDecorationLineStyle_Dot = 4,
+    TextDecorationLineStyle_Dash = 5,
+    TextDecorationLineStyle_DashDot = 6,
+    TextDecorationLineStyle_DashDotDot = 7,
+    TextDecorationLineStyle_Wavy = 8,
+    TextDecorationLineStyle_ThickSingle = 9,
+    TextDecorationLineStyle_DoubleWavy = 11,
+    TextDecorationLineStyle_ThickWavy = 12,
+    TextDecorationLineStyle_LongDash = 13,
+    TextDecorationLineStyle_ThickDash = 14,
+    TextDecorationLineStyle_ThickDashDot = 15,
+    TextDecorationLineStyle_ThickDashDotDot = 16,
+    TextDecorationLineStyle_ThickDot = 17,
+    TextDecorationLineStyle_ThickLongDash = 18,
+    TextDecorationLineStyle_Other = -1
+};
+
+BOOL WINAPI UiaClientsAreListening();
+
+#ifndef __ISelectionProvider2_INTERFACE_DEFINED__
+#define __ISelectionProvider2_INTERFACE_DEFINED__
+DEFINE_GUID(IID_ISelectionProvider2, 0x14f68475, 0xee1c, 0x44f6, 0xa8, 0x69, 0xd2, 0x39, 0x38, 0x1f, 0x0f, 0xe7);
+MIDL_INTERFACE("14f68475-ee1c-44f6-a869-d239381f0fe7")
+ISelectionProvider2 : public ISelectionProvider
+{
+public:
+    virtual HRESULT STDMETHODCALLTYPE get_FirstSelectedItem(__RPC__deref_out_opt IRawElementProviderSimple **retVal) = 0;
+    virtual HRESULT STDMETHODCALLTYPE get_LastSelectedItem(__RPC__deref_out_opt IRawElementProviderSimple **retVal) = 0;
+    virtual HRESULT STDMETHODCALLTYPE get_CurrentSelectedItem(__RPC__deref_out_opt IRawElementProviderSimple **retVal) = 0;
+    virtual HRESULT STDMETHODCALLTYPE get_ItemCount(__RPC__out int *retVal) = 0;
+};
+#ifdef __CRT_UUID_DECL
+__CRT_UUID_DECL(ISelectionProvider2,  0x14f68475, 0xee1c, 0x44f6, 0xa8, 0x69, 0xd2, 0x39, 0x38, 0x1f, 0x0f, 0xe7)
+#endif
+#endif // __ISelectionProvider2_INTERFACE_DEFINED__
+
+#endif // defined(__MINGW32__) || defined(__MINGW64__)
+
+#endif // QT_CONFIG(accessibility)
+
+#endif // QWINDOWSUIAUTOMATION_H