dnd.c

typedef struct {
    IDropTarget dt;
    LONG ref;
} my_IDropTarget;

ULONG __stdcall dnd_AddRef(IDropTarget *lpMyObj)
{
    my_IDropTarget *p = (void*)lpMyObj;
    return InterlockedIncrement(&p->ref);
}

ULONG __stdcall dnd_Release(IDropTarget *lpMyObj)
{
    my_IDropTarget *p = (void*)lpMyObj;
    LONG count = InterlockedDecrement(&p->ref);

    if(!count) {
        free(lpMyObj->lpVtbl);
        free(lpMyObj);
    }

    return count;
}

HRESULT __stdcall dnd_QueryInterface(IDropTarget *lpMyObj, REFIID riid, LPVOID FAR * lppvObj)
{
      *lppvObj = NULL;

//  PRINT_GUID (riid);
  if (IsEqualIID (riid, &IID_IUnknown) || IsEqualIID (riid, &IID_IDropTarget))
    {
      dnd_AddRef (lpMyObj);
      *lppvObj = lpMyObj;
      return S_OK;
    }

    return E_NOINTERFACE;
}

HRESULT __stdcall dnd_DragEnter(IDropTarget *lpMyObj, IDataObject * pDataObject, DWORD grfKeyState, POINTL pt, DWORD * pdwEffect)
{
    *pdwEffect = DROPEFFECT_COPY;
    return S_OK;
}

HRESULT __stdcall dnd_DragOver(IDropTarget *lpMyObj, DWORD grfKeyState, POINTL pt, DWORD * pdwEffect)
{
    *pdwEffect = DROPEFFECT_COPY;
    return S_OK;
}

HRESULT __stdcall dnd_DragLeave(IDropTarget *lpMyObj)
{
    return S_OK;
}

HRESULT __stdcall dnd_Drop(IDropTarget *lpMyObj, IDataObject * pDataObject, DWORD grfKeyState, POINTL pt, DWORD * pdwEffect)
{
    *pdwEffect = DROPEFFECT_COPY;
    debug("droppped!\n");

    if(selected_item->item != ITEM_FRIEND) {
        return S_OK;
    }

    FORMATETC format = {
        .cfFormat = CF_HDROP,
        .dwAspect = DVASPECT_CONTENT,
        .lindex = -1,
        .tymed = TYMED_HGLOBAL,
    };
    STGMEDIUM medium;

    HRESULT r = pDataObject->lpVtbl->GetData(pDataObject, &format, &medium);
    if(r == S_OK) {
        HDROP h = medium.hGlobal;
        int count = DragQueryFile(h, ~0, NULL, 0);
        debug("%u files dropped\n", count);
        int i;

        char *paths = malloc(count * 256);
        if(paths) {
            char *p = paths;
            for(i = 0; i != count; i++) {
                p += DragQueryFile(h, i, p, 256);
                *p++ = '\n';
            }

            tox_postmessage(TOX_SEND_NEW_FILE, (FRIEND*)selected_item->data - friend, 0xFFFF, paths);
        }

        ReleaseStgMedium(&medium);
    } else {
        debug("itz failed! %lX\n", r);
    }

    return S_OK;
}

static void dnd_init(HWND window)
{
    my_IDropTarget *p;
    p = malloc(sizeof(my_IDropTarget));
    p->dt.lpVtbl = malloc(sizeof(*(p->dt.lpVtbl)));
    p->ref = 0;

    p->dt.lpVtbl->QueryInterface = dnd_QueryInterface;
    p->dt.lpVtbl->AddRef = dnd_AddRef;
    p->dt.lpVtbl->Release = dnd_Release;

    p->dt.lpVtbl->DragEnter = dnd_DragEnter;
    p->dt.lpVtbl->DragLeave = dnd_DragLeave;
    p->dt.lpVtbl->DragOver = dnd_DragOver;
    p->dt.lpVtbl->Drop = dnd_Drop;

    CoLockObjectExternal((struct IUnknown*)p, TRUE, FALSE);

    RegisterDragDrop(window, (IDropTarget*)p);
}