From dc0266c88ed148d8e59aa0dbe4057b86ac64f709 Mon Sep 17 00:00:00 2001
From: ge0rdi <ge0rdi@gmx.com>
Date: Sat, 28 Jul 2018 20:20:44 +0200
Subject: [PATCH] Cleanup of the accessibility COM objects (#53)

Fixed issue related to the cleanup of the accessibility COM objects that
may cause Explorer to crash.

Submitted by Ivo Beltchev.

Fixes #53
---
 .../ClassicStartMenuDLL/MenuContainer.cpp     | 41 +++++++++++++++++--
 .../ClassicStartMenuDLL/MenuContainer.h       | 12 +++++-
 2 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.cpp b/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.cpp
index 4a2733a..f269ace 100644
--- a/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.cpp
+++ b/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.cpp
@@ -4426,13 +4426,28 @@ LRESULT CMenuContainer::OnCreate( UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL&
 	if (m_Options&CONTAINER_SEARCH)
 		s_SearchMenu=m_hWnd;
 	s_HotPos=GetMessagePos();
+	m_pAccessible=NULL;
 	if (GetSettingBool(L"EnableAccessibility"))
 	{
-		m_pAccessible=new CMenuAccessible(this);
+		if (SUCCEEDED(m_pAccessibleContext.CoCreateInstance(CLSID_ContextSwitcher)))
+		{
+			CreateAccessibleData createData={this};
+			ComCallData callData={};
+			callData.pUserDefined=&createData;
+			if (SUCCEEDED(m_pAccessibleContext->ContextCallback(CreateAccessible,&callData,IID_IAccessible,4,NULL)))
+			{
+				if (FAILED(CoGetInterfaceAndReleaseStream(createData.pStream,IID_IAccessible,(void**)&m_pAccessible)))
+				{
+					m_pAccessibleContext=NULL;
+				}
+			}
+			else
+			{
+				m_pAccessibleContext=NULL;
+			}
+		}
 		NotifyWinEvent(EVENT_SYSTEM_MENUPOPUPSTART,m_hWnd,OBJID_CLIENT,CHILDID_SELF);
 	}
-	else
-		m_pAccessible=NULL;
 	m_pDropTargetProxy=new CDropTargetProxy(this);
 	RegisterDragDrop(m_hWnd,m_pDropTargetProxy);
 	if (!m_bSubMenu && s_pFrameworkInputPane)
@@ -4441,6 +4456,23 @@ LRESULT CMenuContainer::OnCreate( UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL&
 	return 0;
 }
 
+HRESULT __stdcall CMenuContainer::CreateAccessible( ComCallData *pData )
+{
+	CreateAccessibleData *pCreateData=(CreateAccessibleData*)pData->pUserDefined;
+	CComPtr<CMenuAccessible> pAccessible=new CMenuAccessible(pCreateData->pMenu);
+	HRESULT hr=CoMarshalInterThreadInterfaceInStream(IID_IAccessible,pAccessible,&pCreateData->pStream);
+	if (FAILED(hr))
+	{
+		pAccessible->Reset();
+	}
+	return hr;
+}
+
+HRESULT __stdcall CMenuContainer::ReleaseAccessible( ComCallData *pData )
+{
+	return CoDisconnectContext(INFINITE);
+}
+
 bool CMenuContainer::GetItemRect( int index, RECT &rc )
 {
 	if (index>=0 && index<(int)m_Items.size())
@@ -6111,7 +6143,8 @@ LRESULT CMenuContainer::OnDestroy( UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL
 	if (m_pAccessible)
 	{
 		NotifyWinEvent(EVENT_SYSTEM_MENUPOPUPEND,m_hWnd,OBJID_CLIENT,CHILDID_SELF);
-		m_pAccessible->Reset();
+		m_pAccessibleContext->ContextCallback(ReleaseAccessible,NULL,IID_IAccessible,4,NULL);
+		m_pAccessibleContext=NULL;
 		m_pAccessible=NULL;
 	}
 	if (m_pDropTargetHelper && m_pDragObject)
diff --git a/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.h b/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.h
index 0dcce95..a97cc31 100644
--- a/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.h
+++ b/ClassicStartSrc/ClassicStartMenu/ClassicStartMenuDLL/MenuContainer.h
@@ -12,6 +12,7 @@
 #include "TouchHelper.h"
 #include <vector>
 #include <map>
+#include <ctxtcall.h>
 
 //#define PREVENT_CLOSING // define this to prevent the menu from closing when it is deactivated (useful for debugging)
 //#define REPEAT_ITEMS 10 // define this to repeat each menu item (useful to simulate large menus)
@@ -628,7 +629,8 @@ private:
 	CAbsolutePidl m_Path2[2];
 	CComPtr<IShellItem> m_pDropFolder[2]; // the primary folder (used only as a drop target)
 	CComPtr<IShellView> m_pShellView; // keep the view alive because some buggy namespace extensions clean up if there is no view
-	CComPtr<CMenuAccessible> m_pAccessible;
+	CComPtr<IContextCallback> m_pAccessibleContext;
+	CComPtr<IAccessible> m_pAccessible;
 	CComPtr<CDropTargetProxy> m_pDropTargetProxy;
 	DWORD m_InputCookie;
 	std::vector<int> m_ColumnOffsets;
@@ -983,6 +985,14 @@ private:
 	};
 	static void CloseSubMenus( int flags, CMenuContainer *pAfter );
 
+	struct CreateAccessibleData
+	{
+		CMenuContainer *pMenu;
+		IStream *pStream;
+	};
+	static HRESULT __stdcall CreateAccessible( ComCallData *pData );
+	static HRESULT __stdcall ReleaseAccessible( ComCallData *pData );
+
 	// To control the placement of the start menu, send ClassicStartMenu.StartMenuMsg message right after the start menu is created but before it is displayed
 	// The lParam must point to StartMenuParams
 	// monitorRect - the entire area available to the start menu (sub-menus will use it). It is usually the monitor area but can be less if the Desktop app is docked in Win8