[RESOLVED] IShellDispatch: FolderItemVerbs? (Getting bizarre crash with CoUninitaialize!)

Hi!

I hope this is the correct sub-forum to post this issue.

I'm having a very bizarre problem with the IShellDispatch COM interface, more specifically with the FolderItemVerbs that drives me nuts!

Calling FolderItemVerbs::Release() followed by CoUninitialze() will result in crash. It's clearly reproducible, but only happens 1 out of 10 times :confused:

Running the problematic code in a loop 100% reproduces the crash :cry:

Please see the example program:

Code:

---

static int TestProc(const TCHAR *pcDirectoryName, const TCHAR *pcFileName)
{
        int iSuccess = 0;
       
        IShellDispatch *pShellDispatch = NULL;
        Folder *pFolder = NULL; FolderItem *pItem = NULL;
        FolderItemVerbs *pVerbs = NULL;
       
        HRESULT hr = CoCreateInstance(CLSID_Shell, NULL, CLSCTX_INPROC_SERVER, IID_IShellDispatch, (void**)&pShellDispatch);
        if(FAILED(hr) || (pShellDispatch ==  NULL))
        {
                iSuccess = -3;
                return iSuccess;
        }

        variant_t vaDirectory(pcDirectoryName);
        hr = pShellDispatch->NameSpace(vaDirectory, &pFolder);
        if(FAILED(hr) || (pFolder == NULL))
        {
                iSuccess = -4;
                pShellDispatch->Release();
                return iSuccess;
        }

        variant_t vaFileName(pcFileName);
        hr = pFolder->ParseName(vaFileName, &pItem);
        if(FAILED(hr) || (pItem == NULL))
        {
                iSuccess = -5;
                pFolder->Release();
                pShellDispatch->Release();
                return iSuccess;
        }
       
        hr = pItem->Verbs(&pVerbs);
        if(FAILED(hr) || (pVerbs == NULL))
        {
                iSuccess = -6;
                pItem->Release();
                pFolder->Release();
                pShellDispatch->Release();
                return iSuccess;
        }

        /* Here we would do something with the FolderItemVerbs */

        pVerbs->Release(); //If this line is commented out, we don't get a crash, but a massive memory leak!
        pVerbs = NULL;

        pItem->Release();
        pItem = NULL;

        pFolder->Release();
        pFolder = NULL;

        pShellDispatch->Release();
        pShellDispatch = NULL;
       
        iSuccess = 1;
        return iSuccess;
}

//-----------------------------------------------------------------------------

static unsigned __stdcall ThreadProc(void* pArguments)
{
        HRESULT hr = CoInitialize(NULL);
        if((hr == S_OK) || (hr == S_FALSE))
        {
                threadParam_t *params = (threadParam_t*) pArguments;
                params->returnValue = TestProc(params->pcDirectoryName, params->pcFileName);
                CoUninitialize();
        }
        else
        {
                if(threadParam_t *params = (threadParam_t*) pArguments)
                {
                        params->returnValue = -10;
                }
        }

        return EXIT_SUCCESS;
}

---

Please download the *complete* example code is here:
http://pastie.org/private/0xsnajpia9lsmgnlf2afa


Please also note that I unambiguously tracked down to crash to FolderItemVerbs, because if I never create the FolderItemVerbs object, the crash is gone immediately.

Also if I never call "pVerbs->Release()" before CoUninitialize() the crash is gone too, but this will result in a massive memleak, obviously.

Another strange thing is that the crash will NOT happen, if I run the program under the Debugger! But I can run the program, wait for the crash and then let the Debugger handle the crash.

Unfortunately the Stack Trace that I get then doesn't help much:
http://pastie.org/private/cuwunlun2t5dc5lembpw


I don't think I'm doing anything wrong here. I have checked the code over and over again in the last two days. So this all seems to be a bug in FolderItemVerbs!

Has anybody encountered this before and/or can confirm that this is a bug in FolderItemVerbs? Also, is there any workaround for the problem?

Thanks in advance !!!

Sorry, forgot to mention: The crash is an "0xC0000005: Access Violation" error.

(BTW: Am I blind or is there really no "Edit" button on this forum?)

Quote:

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Originally Posted by MuldeR2

(BTW: Am I blind or is there really no "Edit" button on this forum?)

---

Edit button will appear after about five your posts.

And please:

1. use Code tags, not PHP ones
2. do NOT put more than one statements in one line

Otherwise your code is hard to read/understand!

Okay, got the answer elsewehre.

It turns out this was caused by a "problematic" Shell Extension. In my case it was Tortoise GIT.

And it could be resolved by explicitely dispacthing all messages before CoUninitialize().

Code:

---

static int TestProc(const TCHAR *pcDirectoryName, const TCHAR *pcFileName)
{
    /*see above*/
}

static void DispatchPendingMessages(void)
{
    const DWORD uiTimeout = GetTickCount() + 10000;
    const HANDLE hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    unsigned int counter = 0;
    if(hEvent)
    {
        for(;;)
        {
            MSG Message;
            while(PeekMessage(&Message, NULL, WM_NULL, WM_NULL, PM_REMOVE))
            {
                TranslateMessage(&Message);
                DispatchMessage(&Message);
            }
            const DWORD nWaitResult = MsgWaitForMultipleObjects(1, &hEvent, FALSE, 250, QS_ALLINPUT | QS_ALLPOSTMESSAGE);
            if((nWaitResult == WAIT_TIMEOUT) || (nWaitResult == WAIT_FAILED) || (GetTickCount() >= uiTimeout)) break;
        }
        CloseHandle(hEvent);
    }
}

static unsigned __stdcall ThreadProc(void* pArguments)
{
    HRESULT hr = CoInitialize(NULL);
    if((hr == S_OK) || (hr == S_FALSE))
    {
        threadParam_t *params = (threadParam_t*) pArguments;
        params->returnValue = TestProc(params->pcDirectoryName, params->pcFileName);
        DispatchPendingMessages(); //This is required before CoUninitialize() to avoid crash with certain Shell Extensions !!!
        CoUninitialize();
    }
    else
    {
        if(threadParam_t *params = (threadParam_t*) pArguments)
        {
            params->returnValue = -10;
        }
    }

    return EXIT_SUCCESS;
}

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