From 1aa95f389772901970369afa3abfb207df6f57f6 Mon Sep 17 00:00:00 2001
From: Thamatip Chitpong <tangaming123456@outlook.com>
Date: Tue, 24 May 2022 18:58:24 +0700
Subject: [PATCH] [EXPLORER] Implement CDesktopThread::Destroy (#4371)
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Now Explorer exits properly without using ExitProcess hack.

Signed-off-by: Thamatip Chitpong <tangaming123456@outlook.com>
Reviewed-by: Mark Jansen <mark.jansen@reactos.org>
Reviewed-by: Hermès Bélusca-Maïto <hermes.belusca-maito@reactos.org>
Reviewed-by: Stanislav Motylkov <x86corez@gmail.com>
---
 base/shell/explorer/desktop.cpp | 238 ++++++++++++++++++++------------
 1 file changed, 152 insertions(+), 86 deletions(-)

diff --git a/base/shell/explorer/desktop.cpp b/base/shell/explorer/desktop.cpp
index 94a30ea4cd7..764c9b0f975 100644
--- a/base/shell/explorer/desktop.cpp
+++ b/base/shell/explorer/desktop.cpp
@@ -22,98 +22,164 @@
 
 class CDesktopThread
 {
-    HANDLE m_hEvent;
+private:
     CComPtr<ITrayWindow> m_Tray;
+    HANDLE m_hInitEvent;
+    HANDLE m_hThread;
 
-    DWORD DesktopThreadProc()
-    {
-        CComPtr<IShellDesktopTray> pSdt;
-        HANDLE hDesktop;
-        HRESULT hRet;
-
-        OleInitialize(NULL);
-
-        hRet = m_Tray->QueryInterface(IID_PPV_ARG(IShellDesktopTray, &pSdt));
-        if (!SUCCEEDED(hRet))
-            return 1;
-
-        hDesktop = _SHCreateDesktop(pSdt);
-        if (hDesktop == NULL)
-            return 1;
-
-        if (!SetEvent(m_hEvent))
-        {
-            /* Failed to notify that we initialized successfully, kill ourselves
-            to make the main thread wake up! */
-            return 1;
-        }
-
-        _SHDesktopMessageLoop(hDesktop);
-
-        /* FIXME: Properly rundown the main thread! */
-        ExitProcess(0);
-
-        return 0;
-    }
-
-    static DWORD CALLBACK s_DesktopThreadProc(IN OUT LPVOID lpParameter)
-    {
-        return reinterpret_cast<CDesktopThread*>(lpParameter)->DesktopThreadProc();
-    }
+    DWORD DesktopThreadProc();
+    static DWORD WINAPI s_DesktopThreadProc(LPVOID lpParameter);
 
 public:
-    CDesktopThread() :
-        m_hEvent(NULL),
-        m_Tray(NULL)
-    {
-    }
+    CDesktopThread();
+    ~CDesktopThread();
 
-    HRESULT Initialize(IN OUT ITrayWindow *pTray)
-    {
-        HANDLE hThread;
-        HANDLE Handles[2];
-
-        m_Tray = pTray;
-
-        m_hEvent = CreateEventW(NULL, FALSE, FALSE, NULL);
-        if (!m_hEvent)
-            return E_FAIL;
-
-        hThread = CreateThread(NULL, 0, s_DesktopThreadProc, (PVOID)this, 0, NULL);
-        if (!hThread)
-        {
-            CloseHandle(m_hEvent);
-            return E_FAIL;
-        }
-
-        Handles[0] = hThread;
-        Handles[1] = m_hEvent;
-
-        for (;;)
-        {
-            DWORD WaitResult = MsgWaitForMultipleObjects(_countof(Handles), Handles, FALSE, INFINITE, QS_ALLEVENTS);
-            if (WaitResult == WAIT_OBJECT_0 + _countof(Handles))
-            {
-                TrayProcessMessages(m_Tray);
-            }
-            else if (WaitResult != WAIT_FAILED && WaitResult != WAIT_OBJECT_0)
-            {
-                break;
-            }
-        }
-
-        CloseHandle(hThread);
-        CloseHandle(m_hEvent);
-
-        return S_OK;
-    }
-
-    void Destroy()
-    {
-        return;
-    }
+    HRESULT Initialize(ITrayWindow* pTray);
+    void Destroy();
 };
 
+/*******************************************************************/
+
+CDesktopThread::CDesktopThread():
+    m_Tray(NULL),
+    m_hInitEvent(NULL),
+    m_hThread(NULL)
+{
+}
+
+CDesktopThread::~CDesktopThread()
+{
+    Destroy();
+}
+
+HRESULT CDesktopThread::Initialize(ITrayWindow* pTray)
+{
+    HANDLE Handles[2];
+
+    if (!pTray || m_Tray)
+    {
+        return E_FAIL;
+    }
+
+    m_hInitEvent = CreateEventW(NULL, FALSE, FALSE, NULL);
+    if (!m_hInitEvent)
+    {
+        return E_FAIL;
+    }
+
+    m_Tray = pTray;
+    m_hThread = CreateThread(NULL, 0, s_DesktopThreadProc, (LPVOID)this, 0, NULL);
+
+    if (!m_hThread)
+    {
+        CloseHandle(m_hInitEvent);
+        m_hInitEvent = NULL;
+
+        m_Tray = NULL;
+
+        return E_FAIL;
+    }
+
+    Handles[0] = m_hThread;
+    Handles[1] = m_hInitEvent;
+
+    for (;;)
+    {
+        DWORD WaitResult = MsgWaitForMultipleObjects(_countof(Handles), Handles, FALSE, INFINITE, QS_ALLEVENTS);
+
+        if (WaitResult == WAIT_OBJECT_0 + _countof(Handles))
+        {
+            TrayProcessMessages(m_Tray);
+        }
+        else if (WaitResult != WAIT_FAILED && WaitResult != WAIT_OBJECT_0)
+        {
+            break;
+        }
+        else
+        {
+            CloseHandle(m_hThread);
+            m_hThread = NULL;
+
+            CloseHandle(m_hInitEvent);
+            m_hInitEvent = NULL;
+
+            m_Tray = NULL;
+
+            return E_FAIL;
+        }
+    }
+    return S_OK;
+}
+
+void CDesktopThread::Destroy()
+{
+    if (m_hThread)
+    {
+        DWORD WaitResult = WaitForSingleObject(m_hThread, 0);
+        if (WaitResult == WAIT_TIMEOUT)
+        {
+            /* Send WM_QUIT message to the thread and wait for it to terminate */
+            PostThreadMessageW(GetThreadId(m_hThread), WM_QUIT, 0, 0);
+            WaitForSingleObject(m_hThread, INFINITE);
+        }
+
+        CloseHandle(m_hThread);
+        m_hThread = NULL;
+    }
+
+    if (m_hInitEvent)
+    {
+        CloseHandle(m_hInitEvent);
+        m_hInitEvent = NULL;
+    }
+
+    m_Tray = NULL;
+}
+
+DWORD CDesktopThread::DesktopThreadProc()
+{
+    CComPtr<IShellDesktopTray> pSdt;
+    HANDLE hDesktop;
+    HRESULT hRet;
+    DWORD dwResult = 1;
+
+    OleInitialize(NULL);
+
+    hRet = m_Tray->QueryInterface(IID_PPV_ARG(IShellDesktopTray, &pSdt));
+    if (!SUCCEEDED(hRet))
+    {
+        goto Cleanup;
+    }
+
+    hDesktop = _SHCreateDesktop(pSdt);
+    if (!hDesktop)
+    {
+        goto Cleanup;
+    }
+
+    if (!SetEvent(m_hInitEvent))
+    {
+        /* Failed to notify that we initialized successfully, kill ourselves
+         * to make the main thread wake up! */
+        goto Cleanup;
+    }
+
+    _SHDesktopMessageLoop(hDesktop);
+    dwResult = 0;
+
+Cleanup:
+    OleUninitialize();
+    return dwResult;
+}
+
+DWORD WINAPI CDesktopThread::s_DesktopThreadProc(LPVOID lpParameter)
+{
+    CDesktopThread* pDesktopThread = static_cast<CDesktopThread*>(lpParameter);
+    return pDesktopThread->DesktopThreadProc();
+}
+
+/*******************************************************************/
+
 HANDLE
 DesktopCreateWindow(IN OUT ITrayWindow *Tray)
 {
@@ -133,5 +199,5 @@ VOID
 DesktopDestroyShellWindow(IN HANDLE hDesktop)
 {
     CDesktopThread* pDesktopThread = reinterpret_cast<CDesktopThread*>(hDesktop);
-    pDesktopThread->Destroy();
+    delete pDesktopThread;
 }