Samples/multimedia/directshow/baseclasses/dllentry.cpp

//------------------------------------------------------------------------------
// File: DlleEntry.cpp
//
// Desc: DirectShow base classes - implements classes used to support dll
//       entry points for COM objects.
//
// Copyright (c) 1992-2001 Microsoft Corporation.  All rights reserved.
//------------------------------------------------------------------------------


#include <streams.h>
#include <initguid.h>

#ifdef DEBUG
#ifdef UNICODE
#ifndef _UNICODE
#define _UNICODE
#endif // _UNICODE
#endif // UNICODE

#include <tchar.h>
#endif // DEBUG
#include <strsafe.h>

extern CFactoryTemplate g_Templates[];
extern int g_cTemplates;

HINSTANCE g_hInst;
DWORD	  g_amPlatform;		// VER_PLATFORM_WIN32_WINDOWS etc... (from GetVersionEx)
OSVERSIONINFO g_osInfo;

//
// an instance of this is created by the DLLGetClassObject entrypoint
// it uses the CFactoryTemplate object it is given to support the
// IClassFactory interface

class CClassFactory : public IClassFactory, public CBaseObject
{

private:
    const CFactoryTemplate *const m_pTemplate;

    ULONG m_cRef;

    static int m_cLocked;
public:
    CClassFactory(const CFactoryTemplate *);

    // IUnknown
    STDMETHODIMP QueryInterface(REFIID riid, __deref_out void ** ppv);
    STDMETHODIMP_(ULONG)AddRef();
    STDMETHODIMP_(ULONG)Release();

    // IClassFactory
    STDMETHODIMP CreateInstance(LPUNKNOWN pUnkOuter, REFIID riid, __deref_out void **pv);
    STDMETHODIMP LockServer(BOOL fLock);

    // allow DLLGetClassObject to know about global server lock status
    static BOOL IsLocked() {
        return (m_cLocked > 0);
    };
};

// process-wide dll locked state
int CClassFactory::m_cLocked = 0;

CClassFactory::CClassFactory(const CFactoryTemplate *pTemplate)
: CBaseObject(NAME("Class Factory"))
, m_cRef(0)
, m_pTemplate(pTemplate)
{
}


STDMETHODIMP
CClassFactory::QueryInterface(REFIID riid,__deref_out void **ppv)
{
    CheckPointer(ppv,E_POINTER)
    ValidateReadWritePtr(ppv,sizeof(PVOID));
    *ppv = NULL;

    // any interface on this object is the object pointer.
    if ((riid == IID_IUnknown) || (riid == IID_IClassFactory)) {
        *ppv = (LPVOID) this;
	// AddRef returned interface pointer
        ((LPUNKNOWN) *ppv)->AddRef();
        return NOERROR;
    }

    return ResultFromScode(E_NOINTERFACE);
}


STDMETHODIMP_(ULONG)
CClassFactory::AddRef()
{
    return ++m_cRef;
}

STDMETHODIMP_(ULONG)
CClassFactory::Release()
{
    LONG lRef = InterlockedDecrement((volatile LONG *)&m_cRef);
    if (lRef == 0) {
        delete this;
        return 0;
    } else {
        return lRef;
    }
}

STDMETHODIMP
CClassFactory::CreateInstance(
    LPUNKNOWN pUnkOuter,
    REFIID riid,
    __deref_out void **pv)
{
    CheckPointer(pv,E_POINTER)
    ValidateReadWritePtr(pv,sizeof(void *));
    *pv = NULL;

    /* Enforce the normal OLE rules regarding interfaces and delegation */

    if (pUnkOuter != NULL) {
        if (IsEqualIID(riid,IID_IUnknown) == FALSE) {
            *pv = NULL;
            return ResultFromScode(E_NOINTERFACE);
        }
    }

    /* Create the new object through the derived class's create function */

    HRESULT hr = NOERROR;
    CUnknown *pObj = m_pTemplate->CreateInstance(pUnkOuter, &hr);

    if (pObj == NULL) {
        *pv = NULL;
	if (SUCCEEDED(hr)) {
	    hr = E_OUTOFMEMORY;
	}
	return hr;
    }

    /* Delete the object if we got a construction error */

    if (FAILED(hr)) {
        delete pObj;
        *pv = NULL;
        return hr;
    }

    /* Get a reference counted interface on the object */

    /* We wrap the non-delegating QI with NDAddRef & NDRelease. */
    /* This protects any outer object from being prematurely    */
    /* released by an inner object that may have to be created  */
    /* in order to supply the requested interface.              */
    pObj->NonDelegatingAddRef();
    hr = pObj->NonDelegatingQueryInterface(riid, pv);
    pObj->NonDelegatingRelease();
    /* Note that if NonDelegatingQueryInterface fails, it will  */
    /* not increment the ref count, so the NonDelegatingRelease */
    /* will drop the ref back to zero and the object will "self-*/
    /* destruct".  Hence we don't need additional tidy-up code  */
    /* to cope with NonDelegatingQueryInterface failing.        */

    if (SUCCEEDED(hr)) {
        ASSERT(*pv);
    }

    return hr;
}

STDMETHODIMP
CClassFactory::LockServer(BOOL fLock)
{
    if (fLock) {
        m_cLocked++;
    } else {
        m_cLocked--;
    }
    return NOERROR;
}


// --- COM entrypoints -----------------------------------------

//called by COM to get the class factory object for a given class
__control_entrypoint(DllExport) STDAPI
DllGetClassObject(
    __in REFCLSID rClsID,
    __in REFIID riid,
    __deref_out void **pv)
{
    *pv = NULL;
    if (!(riid == IID_IUnknown) && !(riid == IID_IClassFactory)) {
            return E_NOINTERFACE;
    }

    // traverse the array of templates looking for one with this
    // class id
    for (int i = 0; i < g_cTemplates; i++) {
        const CFactoryTemplate * pT = &g_Templates[i];
        if (pT->IsClassID(rClsID)) {

            // found a template - make a class factory based on this
            // template

            *pv = (LPVOID) (LPUNKNOWN) new CClassFactory(pT);
            if (*pv == NULL) {
                return E_OUTOFMEMORY;
            }
            ((LPUNKNOWN)*pv)->AddRef();
            return NOERROR;
        }
    }
    return CLASS_E_CLASSNOTAVAILABLE;
}

//
//  Call any initialization routines
//
void
DllInitClasses(BOOL bLoading)
{
    int i;

    // traverse the array of templates calling the init routine
    // if they have one
    for (i = 0; i < g_cTemplates; i++) {
        const CFactoryTemplate * pT = &g_Templates[i];
        if (pT->m_lpfnInit != NULL) {
            (*pT->m_lpfnInit)(bLoading, pT->m_ClsID);
        }
    }

}

// called by COM to determine if this dll can be unloaded
// return ok unless there are outstanding objects or a lock requested
// by IClassFactory::LockServer
//
// CClassFactory has a static function that can tell us about the locks,
// and CCOMObject has a static function that can tell us about the active
// object count
STDAPI
DllCanUnloadNow()
{
    DbgLog((LOG_MEMORY,2,TEXT("DLLCanUnloadNow called - IsLocked = %d, Active objects = %d"),
        CClassFactory::IsLocked(),
        CBaseObject::ObjectsActive()));

    if (CClassFactory::IsLocked() || CBaseObject::ObjectsActive()) {
	return S_FALSE;
    } else {
        return S_OK;
    }
}


// --- standard WIN32 entrypoints --------------------------------------


extern "C" void __cdecl __security_init_cookie(void);
extern "C" BOOL WINAPI _DllEntryPoint(HINSTANCE, ULONG, __inout_opt LPVOID);
#pragma comment(linker, "/merge:.CRT=.rdata")

extern "C"
DECLSPEC_NOINLINE
BOOL 
WINAPI
DllEntryPoint(
    HINSTANCE hInstance, 
    ULONG ulReason, 
    __inout_opt LPVOID pv
    )
{
    if ( ulReason == DLL_PROCESS_ATTACH ) {
        // Must happen before any other code is executed.  Thankfully - it's re-entrant
        __security_init_cookie();
    }
    return _DllEntryPoint(hInstance, ulReason, pv);
}


DECLSPEC_NOINLINE
BOOL 
WINAPI
_DllEntryPoint(
    HINSTANCE hInstance, 
    ULONG ulReason, 
    __inout_opt LPVOID pv
    )
{
#ifdef DEBUG
    extern bool g_fDbgInDllEntryPoint;
    g_fDbgInDllEntryPoint = true;
#endif

    switch (ulReason)
    {

    case DLL_PROCESS_ATTACH:
        DisableThreadLibraryCalls(hInstance);
        DbgInitialise(hInstance);

    	{
    	    // The platform identifier is used to work out whether
    	    // full unicode support is available or not.  Hence the
    	    // default will be the lowest common denominator - i.e. N/A
                g_amPlatform = VER_PLATFORM_WIN32_WINDOWS; // win95 assumed in case GetVersionEx fails
    
                g_osInfo.dwOSVersionInfoSize = sizeof(g_osInfo);
                if (GetVersionEx(&g_osInfo)) {
            	g_amPlatform = g_osInfo.dwPlatformId;
    	    } else {
    		DbgLog((LOG_ERROR, 1, TEXT("Failed to get the OS platform, assuming Win95")));
    	    }
    	}

        g_hInst = hInstance;
        DllInitClasses(TRUE);
        break;

    case DLL_PROCESS_DETACH:
        DllInitClasses(FALSE);

#ifdef DEBUG
        if (CBaseObject::ObjectsActive()) {
            DbgSetModuleLevel(LOG_MEMORY, 2);
            TCHAR szInfo[512];
            extern TCHAR m_ModuleName[];     // Cut down module name

            TCHAR FullName[_MAX_PATH];      // Load the full path and module name
            TCHAR *pName;                   // Searches from the end for a backslash

            GetModuleFileName(NULL,FullName,_MAX_PATH);
            pName = _tcsrchr(FullName,'\\');
            if (pName == NULL) {
                pName = FullName;
            } else {
                pName++;
            }

            (void)StringCchPrintf(szInfo, NUMELMS(szInfo), TEXT("Executable: %s  Pid %x  Tid %x. "),
			    pName, GetCurrentProcessId(), GetCurrentThreadId());

            (void)StringCchPrintf(szInfo+lstrlen(szInfo), NUMELMS(szInfo) - lstrlen(szInfo), TEXT("Module %s, %d objects left active!"),
                     m_ModuleName, CBaseObject::ObjectsActive());
            DbgAssert(szInfo, TEXT(__FILE__),__LINE__);

	    // If running remotely wait for the Assert to be acknowledged
	    // before dumping out the object register
            DbgDumpObjectRegister();
        }
        DbgTerminate();
#endif
        break;
    }

#ifdef DEBUG
    g_fDbgInDllEntryPoint = false;
#endif
    return TRUE;
}