/*        DirectDraw Base Functions
 *
 * Copyright 1997-1999 Marcus Meissner
 * Copyright 1998 Lionel Ulmer
 * Copyright 2000-2001 TransGaming Technologies Inc.
 * Copyright 2006 Stefan Dösinger
 * Copyright 2008 Denver Gingerich
 *
 * This file contains the (internal) driver registration functions,
 * driver enumeration APIs and DirectDraw creation functions.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include "config.h"
#include "wine/port.h"

#define DDRAW_INIT_GUID
#include "ddraw_private.h"
#include "rpcproxy.h"

#include "wine/exception.h"
#include "winreg.h"

WINE_DEFAULT_DEBUG_CHANNEL(ddraw);

/* The configured default surface */
enum wined3d_surface_type DefaultSurfaceType = WINED3D_SURFACE_TYPE_OPENGL;

static struct list global_ddraw_list = LIST_INIT(global_ddraw_list);

static HINSTANCE instance;

/* value of ForceRefreshRate */
DWORD force_refresh_rate = 0;

/* Handle table functions */
BOOL ddraw_handle_table_init(struct ddraw_handle_table *t, UINT initial_size)
{
    t->entries = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, initial_size * sizeof(*t->entries));
    if (!t->entries)
    {
        ERR("Failed to allocate handle table memory.\n");
        return FALSE;
    }
    t->free_entries = NULL;
    t->table_size = initial_size;
    t->entry_count = 0;

    return TRUE;
}

void ddraw_handle_table_destroy(struct ddraw_handle_table *t)
{
    HeapFree(GetProcessHeap(), 0, t->entries);
    memset(t, 0, sizeof(*t));
}

DWORD ddraw_allocate_handle(struct ddraw_handle_table *t, void *object, enum ddraw_handle_type type)
{
    struct ddraw_handle_entry *entry;

    if (t->free_entries)
    {
        DWORD idx = t->free_entries - t->entries;
        /* Use a free handle */
        entry = t->free_entries;
        if (entry->type != DDRAW_HANDLE_FREE)
        {
            ERR("Handle %#x (%p) is in the free list, but has type %#x.\n", idx, entry->object, entry->type);
            return DDRAW_INVALID_HANDLE;
        }
        t->free_entries = entry->object;
        entry->object = object;
        entry->type = type;

        return idx;
    }

    if (!(t->entry_count < t->table_size))
    {
        /* Grow the table */
        UINT new_size = t->table_size + (t->table_size >> 1);
        struct ddraw_handle_entry *new_entries = HeapReAlloc(GetProcessHeap(),
                0, t->entries, new_size * sizeof(*t->entries));
        if (!new_entries)
        {
            ERR("Failed to grow the handle table.\n");
            return DDRAW_INVALID_HANDLE;
        }
        t->entries = new_entries;
        t->table_size = new_size;
    }

    entry = &t->entries[t->entry_count];
    entry->object = object;
    entry->type = type;

    return t->entry_count++;
}

void *ddraw_free_handle(struct ddraw_handle_table *t, DWORD handle, enum ddraw_handle_type type)
{
    struct ddraw_handle_entry *entry;
    void *object;

    if (handle == DDRAW_INVALID_HANDLE || handle >= t->entry_count)
    {
        WARN("Invalid handle %#x passed.\n", handle);
        return NULL;
    }

    entry = &t->entries[handle];
    if (entry->type != type)
    {
        WARN("Handle %#x (%p) is not of type %#x.\n", handle, entry->object, type);
        return NULL;
    }

    object = entry->object;
    entry->object = t->free_entries;
    entry->type = DDRAW_HANDLE_FREE;
    t->free_entries = entry;

    return object;
}

void *ddraw_get_object(struct ddraw_handle_table *t, DWORD handle, enum ddraw_handle_type type)
{
    struct ddraw_handle_entry *entry;

    if (handle == DDRAW_INVALID_HANDLE || handle >= t->entry_count)
    {
        WARN("Invalid handle %#x passed.\n", handle);
        return NULL;
    }

    entry = &t->entries[handle];
    if (entry->type != type)
    {
        WARN("Handle %#x (%p) is not of type %#x.\n", handle, entry->object, type);
        return NULL;
    }

    return entry->object;
}

/***********************************************************************
 *
 * Helper function for DirectDrawCreate and friends
 * Creates a new DDraw interface with the given REFIID
 *
 * Interfaces that can be created:
 *  IDirectDraw, IDirectDraw2, IDirectDraw4, IDirectDraw7
 *  IDirect3D, IDirect3D2, IDirect3D3, IDirect3D7. (Does Windows return
 *  IDirect3D interfaces?)
 *
 * Arguments:
 *  guid: ID of the requested driver, NULL for the default driver.
 *        The GUID can be queried with DirectDrawEnumerate(Ex)A/W
 *  DD: Used to return the pointer to the created object
 *  UnkOuter: For aggregation, which is unsupported. Must be NULL
 *  iid: requested version ID.
 *
 * Returns:
 *  DD_OK if the Interface was created successfully
 *  CLASS_E_NOAGGREGATION if UnkOuter is not NULL
 *  E_OUTOFMEMORY if some allocation failed
 *
 ***********************************************************************/
static HRESULT
DDRAW_Create(const GUID *guid,
             void **DD,
             IUnknown *UnkOuter,
             REFIID iid)
{
    enum wined3d_device_type device_type;
    IDirectDrawImpl *This;
    HRESULT hr;

    TRACE("driver_guid %s, ddraw %p, outer_unknown %p, interface_iid %s.\n",
            debugstr_guid(guid), DD, UnkOuter, debugstr_guid(iid));

    *DD = NULL;

    /* We don't care about this guids. Well, there's no special guid anyway
     * OK, we could
     */
    if (guid == (GUID *) DDCREATE_EMULATIONONLY)
    {
        /* Use the reference device id. This doesn't actually change anything,
         * WineD3D always uses OpenGL for D3D rendering. One could make it request
         * indirect rendering
         */
        device_type = WINED3D_DEVICE_TYPE_REF;
    }
    else if(guid == (GUID *) DDCREATE_HARDWAREONLY)
    {
        device_type = WINED3D_DEVICE_TYPE_HAL;
    }
    else
    {
        device_type = 0;
    }

    /* DDraw doesn't support aggregation, according to msdn */
    if (UnkOuter != NULL)
        return CLASS_E_NOAGGREGATION;

    /* DirectDraw creation comes here */
    This = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(IDirectDrawImpl));
    if(!This)
    {
        ERR("Out of memory when creating DirectDraw\n");
        return E_OUTOFMEMORY;
    }

    hr = ddraw_init(This, device_type);
    if (FAILED(hr))
    {
        WARN("Failed to initialize ddraw object, hr %#x.\n", hr);
        HeapFree(GetProcessHeap(), 0, This);
        return hr;
    }

    hr = IDirectDraw7_QueryInterface(&This->IDirectDraw7_iface, iid, DD);
    IDirectDraw7_Release(&This->IDirectDraw7_iface);
    if (SUCCEEDED(hr)) list_add_head(&global_ddraw_list, &This->ddraw_list_entry);
    else WARN("Failed to query interface %s from ddraw object %p.\n", debugstr_guid(iid), This);

    return hr;
}

/***********************************************************************
 * DirectDrawCreate (DDRAW.@)
 *
 * Creates legacy DirectDraw Interfaces. Can't create IDirectDraw7
 * interfaces in theory
 *
 * Arguments, return values: See DDRAW_Create
 *
 ***********************************************************************/
HRESULT WINAPI DECLSPEC_HOTPATCH
DirectDrawCreate(GUID *GUID,
                 LPDIRECTDRAW *DD,
                 IUnknown *UnkOuter)
{
    HRESULT hr;

    TRACE("driver_guid %s, ddraw %p, outer_unknown %p.\n",
            debugstr_guid(GUID), DD, UnkOuter);

    wined3d_mutex_lock();
    hr = DDRAW_Create(GUID, (void **) DD, UnkOuter, &IID_IDirectDraw);
    wined3d_mutex_unlock();

    if (SUCCEEDED(hr))
    {
        hr = IDirectDraw_Initialize(*DD, GUID);
        if (FAILED(hr))
            IDirectDraw_Release(*DD);
    }

    return hr;
}

/***********************************************************************
 * DirectDrawCreateEx (DDRAW.@)
 *
 * Only creates new IDirectDraw7 interfaces, supposed to fail if legacy
 * interfaces are requested.
 *
 * Arguments, return values: See DDRAW_Create
 *
 ***********************************************************************/
HRESULT WINAPI DECLSPEC_HOTPATCH
DirectDrawCreateEx(GUID *guid,
                   LPVOID *dd,
                   REFIID iid,
                   IUnknown *UnkOuter)
{
    HRESULT hr;

    TRACE("driver_guid %s, ddraw %p, interface_iid %s, outer_unknown %p.\n",
            debugstr_guid(guid), dd, debugstr_guid(iid), UnkOuter);

    if (!IsEqualGUID(iid, &IID_IDirectDraw7))
        return DDERR_INVALIDPARAMS;

    wined3d_mutex_lock();
    hr = DDRAW_Create(guid, dd, UnkOuter, iid);
    wined3d_mutex_unlock();

    if (SUCCEEDED(hr))
    {
        IDirectDraw7 *ddraw7 = *(IDirectDraw7 **)dd;
        hr = IDirectDraw7_Initialize(ddraw7, guid);
        if (FAILED(hr))
            IDirectDraw7_Release(ddraw7);
    }

    return hr;
}

/***********************************************************************
 * DirectDrawEnumerateA (DDRAW.@)
 *
 * Enumerates legacy ddraw drivers, ascii version. We only have one
 * driver, which relays to WineD3D. If we were sufficiently cool,
 * we could offer various interfaces, which use a different default surface
 * implementation, but I think it's better to offer this choice in
 * winecfg, because some apps use the default driver, so we would need
 * a winecfg option anyway, and there shouldn't be 2 ways to set one setting
 *
 * Arguments:
 *  Callback: Callback function from the app
 *  Context: Argument to the call back.
 *
 * Returns:
 *  DD_OK on success
 *  E_INVALIDARG if the Callback caused a page fault
 *
 *
 ***********************************************************************/
HRESULT WINAPI DirectDrawEnumerateA(LPDDENUMCALLBACKA Callback, void *Context)
{
    TRACE("callback %p, context %p.\n", Callback, Context);

    TRACE(" Enumerating default DirectDraw HAL interface\n");
    /* We only have one driver */
    __TRY
    {
        static CHAR driver_desc[] = "DirectDraw HAL",
        driver_name[] = "display";

        Callback(NULL, driver_desc, driver_name, Context);
    }
    __EXCEPT_PAGE_FAULT
    {
        return DDERR_INVALIDPARAMS;
    }
    __ENDTRY

    TRACE(" End of enumeration\n");
    return DD_OK;
}

/***********************************************************************
 * DirectDrawEnumerateExA (DDRAW.@)
 *
 * Enumerates DirectDraw7 drivers, ascii version. See
 * the comments above DirectDrawEnumerateA for more details.
 *
 * The Flag member is not supported right now.
 *
 ***********************************************************************/
HRESULT WINAPI DirectDrawEnumerateExA(LPDDENUMCALLBACKEXA Callback, void *Context, DWORD Flags)
{
    TRACE("callback %p, context %p, flags %#x.\n", Callback, Context, Flags);

    if (Flags & ~(DDENUM_ATTACHEDSECONDARYDEVICES |
                  DDENUM_DETACHEDSECONDARYDEVICES |
                  DDENUM_NONDISPLAYDEVICES))
        return DDERR_INVALIDPARAMS;

    if (Flags)
        FIXME("flags 0x%08x not handled\n", Flags);

    TRACE("Enumerating default DirectDraw HAL interface\n");

    /* We only have one driver by now */
    __TRY
    {
        static CHAR driver_desc[] = "DirectDraw HAL",
        driver_name[] = "display";

        /* QuickTime expects the description "DirectDraw HAL" */
        Callback(NULL, driver_desc, driver_name, Context, 0);
    }
    __EXCEPT_PAGE_FAULT
    {
        return DDERR_INVALIDPARAMS;
    }
    __ENDTRY;

    TRACE("End of enumeration\n");
    return DD_OK;
}

/***********************************************************************
 * DirectDrawEnumerateW (DDRAW.@)
 *
 * Enumerates legacy drivers, unicode version.
 * This function is not implemented on Windows.
 *
 ***********************************************************************/
HRESULT WINAPI DirectDrawEnumerateW(LPDDENUMCALLBACKW callback, void *context)
{
    TRACE("callback %p, context %p.\n", callback, context);

    if (!callback)
        return DDERR_INVALIDPARAMS;
    else
        return DDERR_UNSUPPORTED;
}

/***********************************************************************
 * DirectDrawEnumerateExW (DDRAW.@)
 *
 * Enumerates DirectDraw7 drivers, unicode version.
 * This function is not implemented on Windows.
 *
 ***********************************************************************/
HRESULT WINAPI DirectDrawEnumerateExW(LPDDENUMCALLBACKEXW callback, void *context, DWORD flags)
{
    TRACE("callback %p, context %p, flags %#x.\n", callback, context, flags);

    return DDERR_UNSUPPORTED;
}

/***********************************************************************
 * Classfactory implementation.
 ***********************************************************************/

/***********************************************************************
 * CF_CreateDirectDraw
 *
 * DDraw creation function for the class factory
 *
 * Params:
 *  UnkOuter: Set to NULL
 *  iid: ID of the wanted interface
 *  obj: Address to pass the interface pointer back
 *
 * Returns
 *  DD_OK / DDERR*, see DDRAW_Create
 *
 ***********************************************************************/
static HRESULT
CF_CreateDirectDraw(IUnknown* UnkOuter, REFIID iid,
                    void **obj)
{
    HRESULT hr;

    TRACE("outer_unknown %p, riid %s, object %p.\n", UnkOuter, debugstr_guid(iid), obj);

    wined3d_mutex_lock();
    hr = DDRAW_Create(NULL, obj, UnkOuter, iid);
    wined3d_mutex_unlock();

    return hr;
}

/***********************************************************************
 * CF_CreateDirectDraw
 *
 * Clipper creation function for the class factory
 *
 * Params:
 *  UnkOuter: Set to NULL
 *  iid: ID of the wanted interface
 *  obj: Address to pass the interface pointer back
 *
 * Returns
 *  DD_OK / DDERR*, see DDRAW_Create
 *
 ***********************************************************************/
static HRESULT
CF_CreateDirectDrawClipper(IUnknown* UnkOuter, REFIID riid,
                              void **obj)
{
    HRESULT hr;
    IDirectDrawClipper *Clip;

    TRACE("outer_unknown %p, riid %s, object %p.\n", UnkOuter, debugstr_guid(riid), obj);

    wined3d_mutex_lock();
    hr = DirectDrawCreateClipper(0, &Clip, UnkOuter);
    if (hr != DD_OK)
    {
        wined3d_mutex_unlock();
        return hr;
    }

    hr = IDirectDrawClipper_QueryInterface(Clip, riid, obj);
    IDirectDrawClipper_Release(Clip);

    wined3d_mutex_unlock();

    return hr;
}

static const struct object_creation_info object_creation[] =
{
    { &CLSID_DirectDraw,        CF_CreateDirectDraw },
    { &CLSID_DirectDraw7,       CF_CreateDirectDraw },
    { &CLSID_DirectDrawClipper, CF_CreateDirectDrawClipper }
};


/******************************************************************************
 * DirectDraw ClassFactory implementation
 ******************************************************************************/
typedef struct
{
    IClassFactory IClassFactory_iface;

    LONG ref;
    HRESULT (*pfnCreateInstance)(IUnknown *pUnkOuter, REFIID iid, LPVOID *ppObj);
} IClassFactoryImpl;

static inline IClassFactoryImpl *impl_from_IClassFactory(IClassFactory *iface)
{
    return CONTAINING_RECORD(iface, IClassFactoryImpl, IClassFactory_iface);
}

/*******************************************************************************
 * IDirectDrawClassFactory::QueryInterface
 *
 * QueryInterface for the class factory
 *
 * PARAMS
 *    riid   Reference to identifier of queried interface
 *    ppv    Address to return the interface pointer at
 *
 * RETURNS
 *    Success: S_OK
 *    Failure: E_NOINTERFACE
 *
 *******************************************************************************/
static HRESULT WINAPI IDirectDrawClassFactoryImpl_QueryInterface(IClassFactory *iface, REFIID riid,
        void **obj)
{
    IClassFactoryImpl *This = impl_from_IClassFactory(iface);

    TRACE("iface %p, riid %s, object %p.\n", iface, debugstr_guid(riid), obj);

    if (IsEqualGUID(riid, &IID_IUnknown)
        || IsEqualGUID(riid, &IID_IClassFactory))
    {
        IClassFactory_AddRef(iface);
        *obj = This;
        return S_OK;
    }

    WARN("(%p)->(%s,%p),not found\n",This,debugstr_guid(riid),obj);
    return E_NOINTERFACE;
}

/*******************************************************************************
 * IDirectDrawClassFactory::AddRef
 *
 * AddRef for the class factory
 *
 * RETURNS
 *  The new refcount
 *
 *******************************************************************************/
static ULONG WINAPI IDirectDrawClassFactoryImpl_AddRef(IClassFactory *iface)
{
    IClassFactoryImpl *This = impl_from_IClassFactory(iface);
    ULONG ref = InterlockedIncrement(&This->ref);

    TRACE("%p increasing refcount to %u.\n", This, ref);

    return ref;
}

/*******************************************************************************
 * IDirectDrawClassFactory::Release
 *
 * Release for the class factory. If the refcount falls to 0, the object
 * is destroyed
 *
 * RETURNS
 *  The new refcount
 *
 *******************************************************************************/
static ULONG WINAPI IDirectDrawClassFactoryImpl_Release(IClassFactory *iface)
{
    IClassFactoryImpl *This = impl_from_IClassFactory(iface);
    ULONG ref = InterlockedDecrement(&This->ref);

    TRACE("%p decreasing refcount to %u.\n", This, ref);

    if (ref == 0)
        HeapFree(GetProcessHeap(), 0, This);

    return ref;
}


/*******************************************************************************
 * IDirectDrawClassFactory::CreateInstance
 *
 * What is this? Seems to create DirectDraw objects...
 *
 * Params
 *  The usual things???
 *
 * RETURNS
 *  ???
 *
 *******************************************************************************/
static HRESULT WINAPI IDirectDrawClassFactoryImpl_CreateInstance(IClassFactory *iface,
        IUnknown *UnkOuter, REFIID riid, void **obj)
{
    IClassFactoryImpl *This = impl_from_IClassFactory(iface);

    TRACE("iface %p, outer_unknown %p, riid %s, object %p.\n",
            iface, UnkOuter, debugstr_guid(riid), obj);

    return This->pfnCreateInstance(UnkOuter, riid, obj);
}

/*******************************************************************************
 * IDirectDrawClassFactory::LockServer
 *
 * What is this?
 *
 * Params
 *  ???
 *
 * RETURNS
 *  S_OK, because it's a stub
 *
 *******************************************************************************/
static HRESULT WINAPI IDirectDrawClassFactoryImpl_LockServer(IClassFactory *iface, BOOL dolock)
{
    FIXME("iface %p, dolock %#x stub!\n", iface, dolock);

    return S_OK;
}

/*******************************************************************************
 * The class factory VTable
 *******************************************************************************/
static const IClassFactoryVtbl IClassFactory_Vtbl =
{
    IDirectDrawClassFactoryImpl_QueryInterface,
    IDirectDrawClassFactoryImpl_AddRef,
    IDirectDrawClassFactoryImpl_Release,
    IDirectDrawClassFactoryImpl_CreateInstance,
    IDirectDrawClassFactoryImpl_LockServer
};

/*******************************************************************************
 * DllGetClassObject [DDRAW.@]
 * Retrieves class object from a DLL object
 *
 * NOTES
 *    Docs say returns STDAPI
 *
 * PARAMS
 *    rclsid [I] CLSID for the class object
 *    riid   [I] Reference to identifier of interface for class object
 *    ppv    [O] Address of variable to receive interface pointer for riid
 *
 * RETURNS
 *    Success: S_OK
 *    Failure: CLASS_E_CLASSNOTAVAILABLE, E_OUTOFMEMORY, E_INVALIDARG,
 *             E_UNEXPECTED
 */
HRESULT WINAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, LPVOID *ppv)
{
    unsigned int i;
    IClassFactoryImpl *factory;

    TRACE("rclsid %s, riid %s, object %p.\n",
            debugstr_guid(rclsid), debugstr_guid(riid), ppv);

    if (!IsEqualGUID(&IID_IClassFactory, riid)
            && !IsEqualGUID(&IID_IUnknown, riid))
        return E_NOINTERFACE;

    for (i=0; i < sizeof(object_creation)/sizeof(object_creation[0]); i++)
    {
        if (IsEqualGUID(object_creation[i].clsid, rclsid))
            break;
    }

    if (i == sizeof(object_creation)/sizeof(object_creation[0]))
    {
        FIXME("%s: no class found.\n", debugstr_guid(rclsid));
        return CLASS_E_CLASSNOTAVAILABLE;
    }

    factory = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(*factory));
    if (factory == NULL) return E_OUTOFMEMORY;

    factory->IClassFactory_iface.lpVtbl = &IClassFactory_Vtbl;
    factory->ref = 1;

    factory->pfnCreateInstance = object_creation[i].pfnCreateInstance;

    *ppv = factory;
    return S_OK;
}


/*******************************************************************************
 * DllCanUnloadNow [DDRAW.@]  Determines whether the DLL is in use.
 *
 * RETURNS
 *    Success: S_OK
 *    Failure: S_FALSE
 */
HRESULT WINAPI DllCanUnloadNow(void)
{
    TRACE("\n");

    return S_FALSE;
}


/***********************************************************************
 *		DllRegisterServer (DDRAW.@)
 */
HRESULT WINAPI DllRegisterServer(void)
{
    return __wine_register_resources( instance );
}

/***********************************************************************
 *		DllUnregisterServer (DDRAW.@)
 */
HRESULT WINAPI DllUnregisterServer(void)
{
    return __wine_unregister_resources( instance );
}

/*******************************************************************************
 * DestroyCallback
 *
 * Callback function for the EnumSurfaces call in DllMain.
 * Dumps some surface info and releases the surface
 *
 * Params:
 *  surf: The enumerated surface
 *  desc: it's description
 *  context: Pointer to the ddraw impl
 *
 * Returns:
 *  DDENUMRET_OK;
 *******************************************************************************/
static HRESULT WINAPI
DestroyCallback(IDirectDrawSurface7 *surf,
                DDSURFACEDESC2 *desc,
                void *context)
{
    IDirectDrawSurfaceImpl *Impl = impl_from_IDirectDrawSurface7(surf);
    ULONG ref7, ref4, ref3, ref2, ref1, gamma_count, iface_count;

    ref7 = IDirectDrawSurface7_Release(surf);  /* For the EnumSurfaces */
    ref4 = Impl->ref4;
    ref3 = Impl->ref3;
    ref2 = Impl->ref2;
    ref1 = Impl->ref1;
    gamma_count = Impl->gamma_count;

    WARN("Surface %p has an reference counts of 7: %u 4: %u 3: %u 2: %u 1: %u gamma: %u\n",
            Impl, ref7, ref4, ref3, ref2, ref1, gamma_count);

    /* Skip surfaces which are attached somewhere or which are
     * part of a complex compound. They will get released when destroying
     * the root
     */
    if( (!Impl->is_complex_root) || (Impl->first_attached != Impl) )
        return DDENUMRET_OK;

    /* Destroy the surface */
    iface_count = ddraw_surface_release_iface(Impl);
    while (iface_count) iface_count = ddraw_surface_release_iface(Impl);

    return DDENUMRET_OK;
}

/***********************************************************************
 * get_config_key
 *
 * Reads a config key from the registry. Taken from WineD3D
 *
 ***********************************************************************/
static inline DWORD get_config_key(HKEY defkey, HKEY appkey, const char* name, char* buffer, DWORD size)
{
    if (0 != appkey && !RegQueryValueExA( appkey, name, 0, NULL, (LPBYTE) buffer, &size )) return 0;
    if (0 != defkey && !RegQueryValueExA( defkey, name, 0, NULL, (LPBYTE) buffer, &size )) return 0;
    return ERROR_FILE_NOT_FOUND;
}

/***********************************************************************
 * DllMain (DDRAW.0)
 *
 * Could be used to register DirectDraw drivers, if we have more than
 * one. Also used to destroy any objects left at unload if the
 * app didn't release them properly(Gothic 2, Diablo 2, Moto racer, ...)
 *
 ***********************************************************************/
BOOL WINAPI
DllMain(HINSTANCE hInstDLL,
        DWORD Reason,
        LPVOID lpv)
{
    TRACE("(%p,%x,%p)\n", hInstDLL, Reason, lpv);
    if (Reason == DLL_PROCESS_ATTACH)
    {
        char buffer[MAX_PATH+10];
        DWORD size = sizeof(buffer);
        HKEY hkey = 0;
        HKEY appkey = 0;
        WNDCLASSA wc;
        DWORD len;

        /* Register the window class. This is used to create a hidden window
         * for D3D rendering, if the application didn't pass one. It can also
         * be used for creating a device window from SetCooperativeLevel(). */
        wc.style = CS_HREDRAW | CS_VREDRAW;
        wc.lpfnWndProc = DefWindowProcA;
        wc.cbClsExtra = 0;
        wc.cbWndExtra = 0;
        wc.hInstance = hInstDLL;
        wc.hIcon = 0;
        wc.hCursor = 0;
        wc.hbrBackground = GetStockObject(BLACK_BRUSH);
        wc.lpszMenuName = NULL;
        wc.lpszClassName = DDRAW_WINDOW_CLASS_NAME;
        if (!RegisterClassA(&wc))
        {
            ERR("Failed to register ddraw window class, last error %#x.\n", GetLastError());
            return FALSE;
        }

       /* @@ Wine registry key: HKCU\Software\Wine\Direct3D */
       if ( RegOpenKeyA( HKEY_CURRENT_USER, "Software\\Wine\\Direct3D", &hkey ) ) hkey = 0;

       len = GetModuleFileNameA( 0, buffer, MAX_PATH );
       if (len && len < MAX_PATH)
       {
            HKEY tmpkey;
            /* @@ Wine registry key: HKCU\Software\Wine\AppDefaults\app.exe\Direct3D */
            if (!RegOpenKeyA( HKEY_CURRENT_USER, "Software\\Wine\\AppDefaults", &tmpkey ))
            {
                char *p, *appname = buffer;
                if ((p = strrchr( appname, '/' ))) appname = p + 1;
                if ((p = strrchr( appname, '\\' ))) appname = p + 1;
                strcat( appname, "\\Direct3D" );
                TRACE("appname = [%s]\n", appname);
                if (RegOpenKeyA( tmpkey, appname, &appkey )) appkey = 0;
                RegCloseKey( tmpkey );
            }
       }

       if ( 0 != hkey || 0 != appkey )
       {
            if ( !get_config_key( hkey, appkey, "DirectDrawRenderer", buffer, size) )
            {
                if (!strcmp(buffer,"gdi"))
                {
                    TRACE("Defaulting to GDI surfaces\n");
                    DefaultSurfaceType = WINED3D_SURFACE_TYPE_GDI;
                }
                else if (!strcmp(buffer,"opengl"))
                {
                    TRACE("Defaulting to opengl surfaces\n");
                    DefaultSurfaceType = WINED3D_SURFACE_TYPE_OPENGL;
                }
                else
                {
                    ERR("Unknown default surface type. Supported are:\n gdi, opengl\n");
                }
            }
        }

        /* On Windows one can force the refresh rate that DirectDraw uses by
         * setting an override value in dxdiag.  This is documented in KB315614
         * (main article), KB230002, and KB217348.  By comparing registry dumps
         * before and after setting the override, we see that the override value
         * is stored in HKLM\Software\Microsoft\DirectDraw\ForceRefreshRate as a
         * DWORD that represents the refresh rate to force.  We use this
         * registry entry to modify the behavior of SetDisplayMode so that Wine
         * users can override the refresh rate in a Windows-compatible way.
         *
         * dxdiag will not accept a refresh rate lower than 40 or higher than
         * 120 so this value should be within that range.  It is, of course,
         * possible for a user to set the registry entry value directly so that
         * assumption might not hold.
         *
         * There is no current mechanism for setting this value through the Wine
         * GUI.  It would be most appropriate to set this value through a dxdiag
         * clone, but it may be sufficient to use winecfg.
         *
         * TODO: Create a mechanism for setting this value through the Wine GUI.
         */
        if ( !RegOpenKeyA( HKEY_LOCAL_MACHINE, "Software\\Microsoft\\DirectDraw", &hkey ) )
        {
            DWORD type, data;
            size = sizeof(data);
            if (!RegQueryValueExA( hkey, "ForceRefreshRate", NULL, &type, (LPBYTE)&data, &size ) && type == REG_DWORD)
            {
                TRACE("ForceRefreshRate set; overriding refresh rate to %d Hz\n", data);
                force_refresh_rate = data;
            }
            RegCloseKey( hkey );
        }

        instance = hInstDLL;
        DisableThreadLibraryCalls(hInstDLL);
    }
    else if (Reason == DLL_PROCESS_DETACH)
    {
        if(!list_empty(&global_ddraw_list))
        {
            struct list *entry, *entry2;
            WARN("There are still existing DirectDraw interfaces. Wine bug or buggy application?\n");

            /* We remove elements from this loop */
            LIST_FOR_EACH_SAFE(entry, entry2, &global_ddraw_list)
            {
                HRESULT hr;
                DDSURFACEDESC2 desc;
                int i;
                IDirectDrawImpl *ddraw = LIST_ENTRY(entry, IDirectDrawImpl, ddraw_list_entry);

                WARN("DDraw %p has a refcount of %d\n", ddraw, ddraw->ref7 + ddraw->ref4 + ddraw->ref3 + ddraw->ref2 + ddraw->ref1);

                /* Add references to each interface to avoid freeing them unexpectedly */
                IDirectDraw_AddRef(&ddraw->IDirectDraw_iface);
                IDirectDraw2_AddRef(&ddraw->IDirectDraw2_iface);
                IDirectDraw4_AddRef(&ddraw->IDirectDraw4_iface);
                IDirectDraw7_AddRef(&ddraw->IDirectDraw7_iface);

                /* Does a D3D device exist? Destroy it
                    * TODO: Destroy all Vertex buffers, Lights, Materials
                    * and execute buffers too
                    */
                if(ddraw->d3ddevice)
                {
                    WARN("DDraw %p has d3ddevice %p attached\n", ddraw, ddraw->d3ddevice);
                    while(IDirect3DDevice7_Release(&ddraw->d3ddevice->IDirect3DDevice7_iface));
                }

                /* Destroy the swapchain after any 3D device. The 3D device
                 * cleanup code needs a swapchain. Specifically, it tries to
                 * set the current render target to the front buffer. */
                if (ddraw->wined3d_swapchain)
                    ddraw_destroy_swapchain(ddraw);

                /* Try to release the objects
                    * Do an EnumSurfaces to find any hanging surfaces
                    */
                memset(&desc, 0, sizeof(desc));
                desc.dwSize = sizeof(desc);
                for(i = 0; i <= 1; i++)
                {
                    hr = IDirectDraw7_EnumSurfaces(&ddraw->IDirectDraw7_iface, DDENUMSURFACES_ALL,
                            &desc, ddraw, DestroyCallback);
                    if(hr != D3D_OK)
                        ERR("(%p) EnumSurfaces failed, prepare for trouble\n", ddraw);
                }

                if (!list_empty(&ddraw->surface_list))
                    ERR("DDraw %p still has surfaces attached.\n", ddraw);

                /* Release all hanging references to destroy the objects. This
                    * restores the screen mode too
                    */
                while(IDirectDraw_Release(&ddraw->IDirectDraw_iface));
                while(IDirectDraw2_Release(&ddraw->IDirectDraw2_iface));
                while(IDirectDraw4_Release(&ddraw->IDirectDraw4_iface));
                while(IDirectDraw7_Release(&ddraw->IDirectDraw7_iface));
            }
        }

        /* Unregister the window class. */
        UnregisterClassA(DDRAW_WINDOW_CLASS_NAME, hInstDLL);
    }

    return TRUE;
}