src/msw/ole/droptgt.cpp

///////////////////////////////////////////////////////////////////////////////
// Name:        src/msw/ole/droptgt.cpp
// Purpose:     wxDropTarget implementation
// Author:      Vadim Zeitlin
// Modified by:
// Created:
// RCS-ID:      $Id$
// Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
// Licence:     wxWindows licence
///////////////////////////////////////////////////////////////////////////////

// ============================================================================
// Declarations
// ============================================================================

// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#if defined(__BORLANDC__)
    #pragma hdrstop
#endif

#if wxUSE_OLE && wxUSE_DRAG_AND_DROP

#ifndef WX_PRECOMP
    #include "wx/msw/wrapwin.h"
    #include "wx/log.h"
#endif

#include "wx/msw/private.h"

#ifdef __WXWINCE__
    #include <winreg.h>
    #include <ole2.h>
#endif

#ifdef __WIN32__
    #if !defined(__GNUWIN32__) || wxUSE_NORLANDER_HEADERS
        #include <shlobj.h>            // for DROPFILES structure
    #endif
#else
    #include <shellapi.h>
#endif

#include "wx/dnd.h"

#include "wx/msw/ole/oleutils.h"

// ----------------------------------------------------------------------------
// IDropTarget interface: forward all interesting things to wxDropTarget
// (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
//  as wxDropTarget which is 'public' class, while this one is private)
// ----------------------------------------------------------------------------

class wxIDropTarget : public IDropTarget
{
public:
    wxIDropTarget(wxDropTarget *p);
    virtual ~wxIDropTarget();

    // accessors for wxDropTarget
    void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }

    // IDropTarget methods
    STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
    STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
    STDMETHODIMP DragLeave();
    STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);

    DECLARE_IUNKNOWN_METHODS;

protected:
    IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
    wxDropTarget *m_pTarget;      // the real target (we're just a proxy)

    HWND          m_hwnd;         // window we're associated with

    // get default drop effect for given keyboard flags
    static DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction, DWORD pdwEffect);

    DECLARE_NO_COPY_CLASS(wxIDropTarget)
};

// ----------------------------------------------------------------------------
// private functions
// ----------------------------------------------------------------------------

static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
static DWORD ConvertDragResultToEffect(wxDragResult result);

// ============================================================================
// wxIDropTarget implementation
// ============================================================================

// Name    : static wxIDropTarget::GetDropEffect
// Purpose : determine the drop operation from keyboard/mouse state.
// Returns : DWORD combined from DROPEFFECT_xxx constants
// Params  : [in] DWORD flags                 kbd & mouse flags as passed to
//                                            IDropTarget methods
//           [in] wxDragResult defaultAction  the default action of the drop target
//           [in] DWORD pdwEffect             the supported actions of the drop
//                                            source passed to IDropTarget methods
// Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
//           which is the standard behaviour (currently there is no
//           way to redefine it)
DWORD wxIDropTarget::GetDropEffect(DWORD flags,
                                   wxDragResult defaultAction,
                                   DWORD pdwEffect)
{
    DWORD effectiveAction;
    if ( defaultAction == wxDragCopy )
        effectiveAction = flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
    else
        effectiveAction = flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;

    if ( !(effectiveAction & pdwEffect) )
    {
        // the action is not supported by drag source, fall back to something
        // that it does support
        if ( pdwEffect & DROPEFFECT_MOVE )
            effectiveAction = DROPEFFECT_MOVE;
        else if ( pdwEffect & DROPEFFECT_COPY )
            effectiveAction = DROPEFFECT_COPY;
        else if ( pdwEffect & DROPEFFECT_LINK )
            effectiveAction = DROPEFFECT_LINK;
        else
            effectiveAction = DROPEFFECT_NONE;
    }

    return effectiveAction;
}

wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
{
  m_pTarget      = pTarget;
  m_pIDataObject = NULL;
}

wxIDropTarget::~wxIDropTarget()
{
}

BEGIN_IID_TABLE(wxIDropTarget)
  ADD_IID(Unknown)
  ADD_IID(DropTarget)
END_IID_TABLE;

IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)

// Name    : wxIDropTarget::DragEnter
// Purpose : Called when the mouse enters the window (dragging something)
// Returns : S_OK
// Params  : [in]    IDataObject *pIDataSource : source data
//           [in]    DWORD        grfKeyState  : kbd & mouse state
//           [in]    POINTL       pt           : mouse coordinates
//           [in/out]DWORD       *pdwEffect    : effect flag
//                                               In:  Supported effects
//                                               Out: Resulting effect
// Notes   :
STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
                                      DWORD        grfKeyState,
                                      POINTL       pt,
                                      DWORD       *pdwEffect)
{
    wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));

    wxASSERT_MSG( m_pIDataObject == NULL,
                  _T("drop target must have data object") );

    // show the list of formats supported by the source data object for the
    // debugging purposes, this is quite useful sometimes - please don't remove
#if 0
    IEnumFORMATETC *penumFmt;
    if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
    {
        FORMATETC fmt;
        while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
        {
            wxLogDebug(_T("Drop source supports format %s"),
                       wxDataObject::GetFormatName(fmt.cfFormat));
        }

        penumFmt->Release();
    }
    else
    {
        wxLogLastError(_T("IDataObject::EnumFormatEtc"));
    }
#endif // 0

    if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
        // we don't accept this kind of data
        *pdwEffect = DROPEFFECT_NONE;

        return S_OK;
    }

    // get hold of the data object
    m_pIDataObject = pIDataSource;
    m_pIDataObject->AddRef();

    // we need client coordinates to pass to wxWin functions
    if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
    {
        wxLogLastError(wxT("ScreenToClient"));
    }

    // give some visual feedback
    *pdwEffect = ConvertDragResultToEffect(
        m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
            GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect))
                    )
                 );

    return S_OK;
}

// Name    : wxIDropTarget::DragOver
// Purpose : Indicates that the mouse was moved inside the window represented
//           by this drop target.
// Returns : S_OK
// Params  : [in]    DWORD   grfKeyState     kbd & mouse state
//           [in]    POINTL  pt              mouse coordinates
//           [in/out]LPDWORD pdwEffect       current effect flag
// Notes   : We're called on every WM_MOUSEMOVE, so this function should be
//           very efficient.
STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
                                     POINTL  pt,
                                     LPDWORD pdwEffect)
{
    // there are too many of them... wxLogDebug("IDropTarget::DragOver");

    wxDragResult result;
    if ( m_pIDataObject ) {
        result = ConvertDragEffectToResult(
            GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect));
    }
    else {
        // can't accept data anyhow normally
        result = wxDragNone;
    }

    if ( result != wxDragNone ) {
        // we need client coordinates to pass to wxWin functions
        if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
        {
            wxLogLastError(wxT("ScreenToClient"));
        }

        *pdwEffect = ConvertDragResultToEffect(
                        m_pTarget->OnDragOver(pt.x, pt.y, result)
                     );
    }
    else {
        *pdwEffect = DROPEFFECT_NONE;
    }

    return S_OK;
}

// Name    : wxIDropTarget::DragLeave
// Purpose : Informs the drop target that the operation has left its window.
// Returns : S_OK
// Notes   : good place to do any clean-up
STDMETHODIMP wxIDropTarget::DragLeave()
{
  wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));

  // remove the UI feedback
  m_pTarget->OnLeave();

  // release the held object
  RELEASE_AND_NULL(m_pIDataObject);

  return S_OK;
}

// Name    : wxIDropTarget::Drop
// Purpose : Instructs the drop target to paste data that was just now
//           dropped on it.
// Returns : S_OK
// Params  : [in]    IDataObject *pIDataSource     the data to paste
//           [in]    DWORD        grfKeyState      kbd & mouse state
//           [in]    POINTL       pt               where the drop occurred?
//           [in/out]DWORD       *pdwEffect        operation effect
// Notes   :
STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
                                 DWORD        grfKeyState,
                                 POINTL       pt,
                                 DWORD       *pdwEffect)
{
    wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));

    // TODO I don't know why there is this parameter, but so far I assume
    //      that it's the same we've already got in DragEnter
    wxASSERT( m_pIDataObject == pIDataSource );

    // we need client coordinates to pass to wxWin functions
    if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
    {
        wxLogLastError(wxT("ScreenToClient"));
    }

    // first ask the drop target if it wants data
    if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
        // it does, so give it the data source
        m_pTarget->SetDataSource(pIDataSource);

        // and now it has the data
        wxDragResult rc = ConvertDragEffectToResult(
            GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect));
        rc = m_pTarget->OnData(pt.x, pt.y, rc);
        if ( wxIsDragResultOk(rc) ) {
            // operation succeeded
            *pdwEffect = ConvertDragResultToEffect(rc);
        }
        else {
            *pdwEffect = DROPEFFECT_NONE;
        }
    }
    else {
        // OnDrop() returned false, no need to copy data
        *pdwEffect = DROPEFFECT_NONE;
    }

    // release the held object
    RELEASE_AND_NULL(m_pIDataObject);

    return S_OK;
}

// ============================================================================
// wxDropTarget implementation
// ============================================================================

// ----------------------------------------------------------------------------
// ctor/dtor
// ----------------------------------------------------------------------------

wxDropTarget::wxDropTarget(wxDataObject *dataObj)
            : wxDropTargetBase(dataObj)
{
    // create an IDropTarget implementation which will notify us about d&d
    // operations.
    m_pIDropTarget = new wxIDropTarget(this);
    m_pIDropTarget->AddRef();
}

wxDropTarget::~wxDropTarget()
{
    ReleaseInterface(m_pIDropTarget);
}

// ----------------------------------------------------------------------------
// [un]register drop handler
// ----------------------------------------------------------------------------

bool wxDropTarget::Register(WXHWND hwnd)
{
    // FIXME
    // RegisterDragDrop not available on Windows CE >= 400?
    // Or maybe we can dynamically load them from ceshell.dll
    // or similar.
#if defined(__WXWINCE__) && _WIN32_WCE >= 400
    wxUnusedVar(hwnd);
    return false;
#else
    HRESULT hr;

    // May exist in later WinCE versions
#ifndef __WXWINCE__
    hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
    if ( FAILED(hr) ) {
        wxLogApiError(wxT("CoLockObjectExternal"), hr);
        return false;
    }
#endif

    hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
    if ( FAILED(hr) ) {
    // May exist in later WinCE versions
#ifndef __WXWINCE__
        ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
#endif
        wxLogApiError(wxT("RegisterDragDrop"), hr);
        return false;
    }

    // we will need the window handle for coords transformation later
    m_pIDropTarget->SetHwnd((HWND)hwnd);

    return true;
#endif
}

void wxDropTarget::Revoke(WXHWND hwnd)
{
#if defined(__WXWINCE__) && _WIN32_WCE >= 400
    // Not available, see note above
    wxUnusedVar(hwnd);
#else
    HRESULT hr = ::RevokeDragDrop((HWND) hwnd);

    if ( FAILED(hr) ) {
        wxLogApiError(wxT("RevokeDragDrop"), hr);
    }

    // May exist in later WinCE versions
#ifndef __WXWINCE__
    ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
#endif

    m_pIDropTarget->SetHwnd(0);
#endif
}

// ----------------------------------------------------------------------------
// base class pure virtuals
// ----------------------------------------------------------------------------

// OnDrop() is called only if we previously returned true from
// IsAcceptedData(), so no need to check anything here
bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
{
    return true;
}

// copy the data from the data source to the target data object
bool wxDropTarget::GetData()
{
    wxDataFormat format = GetSupportedFormat(m_pIDataSource);
    if ( format == wxDF_INVALID ) {
        // this is strange because IsAcceptedData() succeeded previously!
        wxFAIL_MSG(wxT("strange - did supported formats list change?"));

        return false;
    }

    STGMEDIUM stm;
    FORMATETC fmtMemory;
    fmtMemory.cfFormat  = format;
    fmtMemory.ptd       = NULL;
    fmtMemory.dwAspect  = DVASPECT_CONTENT;
    fmtMemory.lindex    = -1;
    fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media

    bool rc = false;

    HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
    if ( SUCCEEDED(hr) ) {
        IDataObject *dataObject = m_dataObject->GetInterface();

        hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
        if ( SUCCEEDED(hr) ) {
            rc = true;
        }
        else {
            wxLogApiError(wxT("IDataObject::SetData()"), hr);
        }
    }
    else {
        wxLogApiError(wxT("IDataObject::GetData()"), hr);
    }

    return rc;
}

// ----------------------------------------------------------------------------
// callbacks used by wxIDropTarget
// ----------------------------------------------------------------------------

// we need a data source, so wxIDropTarget gives it to us using this function
void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
{
    m_pIDataSource = pIDataSource;
}

// determine if we accept data of this type
bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
{
    return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
}

// ----------------------------------------------------------------------------
// helper functions
// ----------------------------------------------------------------------------

wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
{
    // this strucutre describes a data of any type (first field will be
    // changing) being passed through global memory block.
    static FORMATETC s_fmtMemory = {
        0,
        NULL,
        DVASPECT_CONTENT,
        -1,
        TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
    };

    // get the list of supported formats
    size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
    wxDataFormat format;
    wxDataFormat *formats;
    formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];

    m_dataObject->GetAllFormats(formats, wxDataObject::Set);

    // cycle through all supported formats
    size_t n;
    for ( n = 0; n < nFormats; n++ ) {
        s_fmtMemory.cfFormat = formats[n];

        // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
        //     for file drag and drop (format == CF_HDROP)
        if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
            format = formats[n];

            break;
        }
    }

    if ( formats != &format ) {
        // free memory if we allocated it
        delete [] formats;
    }

    return n < nFormats ? format : wxFormatInvalid;
}

// ----------------------------------------------------------------------------
// private functions
// ----------------------------------------------------------------------------

static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
{
    switch ( dwEffect ) {
        case DROPEFFECT_COPY:
            return wxDragCopy;

        case DROPEFFECT_LINK:
            return wxDragLink;

        case DROPEFFECT_MOVE:
            return wxDragMove;

        default:
            wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
            // fall through

        case DROPEFFECT_NONE:
            return wxDragNone;
    }
}

static DWORD ConvertDragResultToEffect(wxDragResult result)
{
    switch ( result ) {
        case wxDragCopy:
            return DROPEFFECT_COPY;

        case wxDragLink:
            return DROPEFFECT_LINK;

        case wxDragMove:
            return DROPEFFECT_MOVE;

        default:
            wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
            // fall through

        case wxDragNone:
            return DROPEFFECT_NONE;
    }
}

#endif // wxUSE_OLE && wxUSE_DRAG_AND_DROP
Commit	Line	Data
	1	///////////////////////////////////////////////////////////////////////////////
	2	// Name: src/msw/ole/droptgt.cpp
	3	// Purpose: wxDropTarget implementation
	4	// Author: Vadim Zeitlin
	5	// Modified by:
	6	// Created:
	7	// RCS-ID: $Id$
	8	// Copyright: (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
	9	// Licence: wxWindows licence
	10	///////////////////////////////////////////////////////////////////////////////
	11
	12	// ============================================================================
	13	// Declarations
	14	// ============================================================================
	15
	16	// ----------------------------------------------------------------------------
	17	// headers
	18	// ----------------------------------------------------------------------------
	19
	20	// For compilers that support precompilation, includes "wx.h".
	21	#include "wx/wxprec.h"
	22
	23	#if defined(__BORLANDC__)
	24	#pragma hdrstop
	25	#endif
	26
	27	#if wxUSE_OLE && wxUSE_DRAG_AND_DROP
	28
	29	#ifndef WX_PRECOMP
	30	#include "wx/msw/wrapwin.h"
	31	#include "wx/log.h"
	32	#endif
	33
	34	#include "wx/msw/private.h"
	35
	36	#ifdef __WXWINCE__
	37	#include <winreg.h>
	38	#include <ole2.h>
	39	#endif
	40
	41	#ifdef __WIN32__
	42	#if !defined(__GNUWIN32__) \|\| wxUSE_NORLANDER_HEADERS
	43	#include <shlobj.h> // for DROPFILES structure
	44	#endif
	45	#else
	46	#include <shellapi.h>
	47	#endif
	48
	49	#include "wx/dnd.h"
	50
	51	#include "wx/msw/ole/oleutils.h"
	52
	53	// ----------------------------------------------------------------------------
	54	// IDropTarget interface: forward all interesting things to wxDropTarget
	55	// (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
	56	// as wxDropTarget which is 'public' class, while this one is private)
	57	// ----------------------------------------------------------------------------
	58
	59	class wxIDropTarget : public IDropTarget
	60	{
	61	public:
	62	wxIDropTarget(wxDropTarget *p);
	63	virtual ~wxIDropTarget();
	64
	65	// accessors for wxDropTarget
	66	void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
	67
	68	// IDropTarget methods
	69	STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
	70	STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
	71	STDMETHODIMP DragLeave();
	72	STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
	73
	74	DECLARE_IUNKNOWN_METHODS;
	75
	76	protected:
	77	IDataObject *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
	78	wxDropTarget *m_pTarget; // the real target (we're just a proxy)
	79
	80	HWND m_hwnd; // window we're associated with
	81
	82	// get default drop effect for given keyboard flags
	83	static DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction, DWORD pdwEffect);
	84
	85	DECLARE_NO_COPY_CLASS(wxIDropTarget)
	86	};
	87
	88	// ----------------------------------------------------------------------------
	89	// private functions
	90	// ----------------------------------------------------------------------------
	91
	92	static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
	93	static DWORD ConvertDragResultToEffect(wxDragResult result);
	94
	95	// ============================================================================
	96	// wxIDropTarget implementation
	97	// ============================================================================
	98
	99	// Name : static wxIDropTarget::GetDropEffect
	100	// Purpose : determine the drop operation from keyboard/mouse state.
	101	// Returns : DWORD combined from DROPEFFECT_xxx constants
	102	// Params : [in] DWORD flags kbd & mouse flags as passed to
	103	// IDropTarget methods
	104	// [in] wxDragResult defaultAction the default action of the drop target
	105	// [in] DWORD pdwEffect the supported actions of the drop
	106	// source passed to IDropTarget methods
	107	// Notes : We do "move" normally and "copy" if <Ctrl> is pressed,
	108	// which is the standard behaviour (currently there is no
	109	// way to redefine it)
	110	DWORD wxIDropTarget::GetDropEffect(DWORD flags,
	111	wxDragResult defaultAction,
	112	DWORD pdwEffect)
	113	{
	114	DWORD effectiveAction;
	115	if ( defaultAction == wxDragCopy )
	116	effectiveAction = flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
	117	else
	118	effectiveAction = flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
	119
	120	if ( !(effectiveAction & pdwEffect) )
	121	{
	122	// the action is not supported by drag source, fall back to something
	123	// that it does support
	124	if ( pdwEffect & DROPEFFECT_MOVE )
	125	effectiveAction = DROPEFFECT_MOVE;
	126	else if ( pdwEffect & DROPEFFECT_COPY )
	127	effectiveAction = DROPEFFECT_COPY;
	128	else if ( pdwEffect & DROPEFFECT_LINK )
	129	effectiveAction = DROPEFFECT_LINK;
	130	else
	131	effectiveAction = DROPEFFECT_NONE;
	132	}
	133
	134	return effectiveAction;
	135	}
	136
	137	wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
	138	{
	139	m_pTarget = pTarget;
	140	m_pIDataObject = NULL;
	141	}
	142
	143	wxIDropTarget::~wxIDropTarget()
	144	{
	145	}
	146
	147	BEGIN_IID_TABLE(wxIDropTarget)
	148	ADD_IID(Unknown)
	149	ADD_IID(DropTarget)
	150	END_IID_TABLE;
	151
	152	IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
	153
	154	// Name : wxIDropTarget::DragEnter
	155	// Purpose : Called when the mouse enters the window (dragging something)
	156	// Returns : S_OK
	157	// Params : [in] IDataObject *pIDataSource : source data
	158	// [in] DWORD grfKeyState : kbd & mouse state
	159	// [in] POINTL pt : mouse coordinates
	160	// [in/out]DWORD *pdwEffect : effect flag
	161	// In: Supported effects
	162	// Out: Resulting effect
	163	// Notes :
	164	STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
	165	DWORD grfKeyState,
	166	POINTL pt,
	167	DWORD *pdwEffect)
	168	{
	169	wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
	170
	171	wxASSERT_MSG( m_pIDataObject == NULL,
	172	_T("drop target must have data object") );
	173
	174	// show the list of formats supported by the source data object for the
	175	// debugging purposes, this is quite useful sometimes - please don't remove
	176	#if 0
	177	IEnumFORMATETC *penumFmt;
	178	if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
	179	{
	180	FORMATETC fmt;
	181	while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
	182	{
	183	wxLogDebug(_T("Drop source supports format %s"),
	184	wxDataObject::GetFormatName(fmt.cfFormat));
	185	}
	186
	187	penumFmt->Release();
	188	}
	189	else
	190	{
	191	wxLogLastError(_T("IDataObject::EnumFormatEtc"));
	192	}
	193	#endif // 0
	194
	195	if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
	196	// we don't accept this kind of data
	197	*pdwEffect = DROPEFFECT_NONE;
	198
	199	return S_OK;
	200	}
	201
	202	// get hold of the data object
	203	m_pIDataObject = pIDataSource;
	204	m_pIDataObject->AddRef();
	205
	206	// we need client coordinates to pass to wxWin functions
	207	if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
	208	{
	209	wxLogLastError(wxT("ScreenToClient"));
	210	}
	211
	212	// give some visual feedback
	213	*pdwEffect = ConvertDragResultToEffect(
	214	m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
	215	GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect))
	216	)
	217	);
	218
	219	return S_OK;
	220	}
	221
	222	// Name : wxIDropTarget::DragOver
	223	// Purpose : Indicates that the mouse was moved inside the window represented
	224	// by this drop target.
	225	// Returns : S_OK
	226	// Params : [in] DWORD grfKeyState kbd & mouse state
	227	// [in] POINTL pt mouse coordinates
	228	// [in/out]LPDWORD pdwEffect current effect flag
	229	// Notes : We're called on every WM_MOUSEMOVE, so this function should be
	230	// very efficient.
	231	STDMETHODIMP wxIDropTarget::DragOver(DWORD grfKeyState,
	232	POINTL pt,
	233	LPDWORD pdwEffect)
	234	{
	235	// there are too many of them... wxLogDebug("IDropTarget::DragOver");
	236
	237	wxDragResult result;
	238	if ( m_pIDataObject ) {
	239	result = ConvertDragEffectToResult(
	240	GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect));
	241	}
	242	else {
	243	// can't accept data anyhow normally
	244	result = wxDragNone;
	245	}
	246
	247	if ( result != wxDragNone ) {
	248	// we need client coordinates to pass to wxWin functions
	249	if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
	250	{
	251	wxLogLastError(wxT("ScreenToClient"));
	252	}
	253
	254	*pdwEffect = ConvertDragResultToEffect(
	255	m_pTarget->OnDragOver(pt.x, pt.y, result)
	256	);
	257	}
	258	else {
	259	*pdwEffect = DROPEFFECT_NONE;
	260	}
	261
	262	return S_OK;
	263	}
	264
	265	// Name : wxIDropTarget::DragLeave
	266	// Purpose : Informs the drop target that the operation has left its window.
	267	// Returns : S_OK
	268	// Notes : good place to do any clean-up
	269	STDMETHODIMP wxIDropTarget::DragLeave()
	270	{
	271	wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
	272
	273	// remove the UI feedback
	274	m_pTarget->OnLeave();
	275
	276	// release the held object
	277	RELEASE_AND_NULL(m_pIDataObject);
	278
	279	return S_OK;
	280	}
	281
	282	// Name : wxIDropTarget::Drop
	283	// Purpose : Instructs the drop target to paste data that was just now
	284	// dropped on it.
	285	// Returns : S_OK
	286	// Params : [in] IDataObject *pIDataSource the data to paste
	287	// [in] DWORD grfKeyState kbd & mouse state
	288	// [in] POINTL pt where the drop occurred?
	289	// [in/out]DWORD *pdwEffect operation effect
	290	// Notes :
	291	STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
	292	DWORD grfKeyState,
	293	POINTL pt,
	294	DWORD *pdwEffect)
	295	{
	296	wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
	297
	298	// TODO I don't know why there is this parameter, but so far I assume
	299	// that it's the same we've already got in DragEnter
	300	wxASSERT( m_pIDataObject == pIDataSource );
	301
	302	// we need client coordinates to pass to wxWin functions
	303	if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
	304	{
	305	wxLogLastError(wxT("ScreenToClient"));
	306	}
	307
	308	// first ask the drop target if it wants data
	309	if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
	310	// it does, so give it the data source
	311	m_pTarget->SetDataSource(pIDataSource);
	312
	313	// and now it has the data
	314	wxDragResult rc = ConvertDragEffectToResult(
	315	GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect));
	316	rc = m_pTarget->OnData(pt.x, pt.y, rc);
	317	if ( wxIsDragResultOk(rc) ) {
	318	// operation succeeded
	319	*pdwEffect = ConvertDragResultToEffect(rc);
	320	}
	321	else {
	322	*pdwEffect = DROPEFFECT_NONE;
	323	}
	324	}
	325	else {
	326	// OnDrop() returned false, no need to copy data
	327	*pdwEffect = DROPEFFECT_NONE;
	328	}
	329
	330	// release the held object
	331	RELEASE_AND_NULL(m_pIDataObject);
	332
	333	return S_OK;
	334	}
	335
	336	// ============================================================================
	337	// wxDropTarget implementation
	338	// ============================================================================
	339
	340	// ----------------------------------------------------------------------------
	341	// ctor/dtor
	342	// ----------------------------------------------------------------------------
	343
	344	wxDropTarget::wxDropTarget(wxDataObject *dataObj)
	345	: wxDropTargetBase(dataObj)
	346	{
	347	// create an IDropTarget implementation which will notify us about d&d
	348	// operations.
	349	m_pIDropTarget = new wxIDropTarget(this);
	350	m_pIDropTarget->AddRef();
	351	}
	352
	353	wxDropTarget::~wxDropTarget()
	354	{
	355	ReleaseInterface(m_pIDropTarget);
	356	}
	357
	358	// ----------------------------------------------------------------------------
	359	// [un]register drop handler
	360	// ----------------------------------------------------------------------------
	361
	362	bool wxDropTarget::Register(WXHWND hwnd)
	363	{
	364	// FIXME
	365	// RegisterDragDrop not available on Windows CE >= 400?
	366	// Or maybe we can dynamically load them from ceshell.dll
	367	// or similar.
	368	#if defined(__WXWINCE__) && _WIN32_WCE >= 400
	369	wxUnusedVar(hwnd);
	370	return false;
	371	#else
	372	HRESULT hr;
	373
	374	// May exist in later WinCE versions
	375	#ifndef __WXWINCE__
	376	hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
	377	if ( FAILED(hr) ) {
	378	wxLogApiError(wxT("CoLockObjectExternal"), hr);
	379	return false;
	380	}
	381	#endif
	382
	383	hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
	384	if ( FAILED(hr) ) {
	385	// May exist in later WinCE versions
	386	#ifndef __WXWINCE__
	387	::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
	388	#endif
	389	wxLogApiError(wxT("RegisterDragDrop"), hr);
	390	return false;
	391	}
	392
	393	// we will need the window handle for coords transformation later
	394	m_pIDropTarget->SetHwnd((HWND)hwnd);
	395
	396	return true;
	397	#endif
	398	}
	399
	400	void wxDropTarget::Revoke(WXHWND hwnd)
	401	{
	402	#if defined(__WXWINCE__) && _WIN32_WCE >= 400
	403	// Not available, see note above
	404	wxUnusedVar(hwnd);
	405	#else
	406	HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
	407
	408	if ( FAILED(hr) ) {
	409	wxLogApiError(wxT("RevokeDragDrop"), hr);
	410	}
	411
	412	// May exist in later WinCE versions
	413	#ifndef __WXWINCE__
	414	::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
	415	#endif
	416
	417	m_pIDropTarget->SetHwnd(0);
	418	#endif
	419	}
	420
	421	// ----------------------------------------------------------------------------
	422	// base class pure virtuals
	423	// ----------------------------------------------------------------------------
	424
	425	// OnDrop() is called only if we previously returned true from
	426	// IsAcceptedData(), so no need to check anything here
	427	bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
	428	{
	429	return true;
	430	}
	431
	432	// copy the data from the data source to the target data object
	433	bool wxDropTarget::GetData()
	434	{
	435	wxDataFormat format = GetSupportedFormat(m_pIDataSource);
	436	if ( format == wxDF_INVALID ) {
	437	// this is strange because IsAcceptedData() succeeded previously!
	438	wxFAIL_MSG(wxT("strange - did supported formats list change?"));
	439
	440	return false;
	441	}
	442
	443	STGMEDIUM stm;
	444	FORMATETC fmtMemory;
	445	fmtMemory.cfFormat = format;
	446	fmtMemory.ptd = NULL;
	447	fmtMemory.dwAspect = DVASPECT_CONTENT;
	448	fmtMemory.lindex = -1;
	449	fmtMemory.tymed = TYMED_HGLOBAL; // TODO to add other media
	450
	451	bool rc = false;
	452
	453	HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
	454	if ( SUCCEEDED(hr) ) {
	455	IDataObject *dataObject = m_dataObject->GetInterface();
	456
	457	hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
	458	if ( SUCCEEDED(hr) ) {
	459	rc = true;
	460	}
	461	else {
	462	wxLogApiError(wxT("IDataObject::SetData()"), hr);
	463	}
	464	}
	465	else {
	466	wxLogApiError(wxT("IDataObject::GetData()"), hr);
	467	}
	468
	469	return rc;
	470	}
	471
	472	// ----------------------------------------------------------------------------
	473	// callbacks used by wxIDropTarget
	474	// ----------------------------------------------------------------------------
	475
	476	// we need a data source, so wxIDropTarget gives it to us using this function
	477	void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
	478	{
	479	m_pIDataSource = pIDataSource;
	480	}
	481
	482	// determine if we accept data of this type
	483	bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
	484	{
	485	return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
	486	}
	487
	488	// ----------------------------------------------------------------------------
	489	// helper functions
	490	// ----------------------------------------------------------------------------
	491
	492	wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
	493	{
	494	// this strucutre describes a data of any type (first field will be
	495	// changing) being passed through global memory block.
	496	static FORMATETC s_fmtMemory = {
	497	0,
	498	NULL,
	499	DVASPECT_CONTENT,
	500	-1,
	501	TYMED_HGLOBAL // TODO is it worth supporting other tymeds here?
	502	};
	503
	504	// get the list of supported formats
	505	size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
	506	wxDataFormat format;
	507	wxDataFormat *formats;
	508	formats = nFormats == 1 ? &format : new wxDataFormat[nFormats];
	509
	510	m_dataObject->GetAllFormats(formats, wxDataObject::Set);
	511
	512	// cycle through all supported formats
	513	size_t n;
	514	for ( n = 0; n < nFormats; n++ ) {
	515	s_fmtMemory.cfFormat = formats[n];
	516
	517	// NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
	518	// for file drag and drop (format == CF_HDROP)
	519	if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
	520	format = formats[n];
	521
	522	break;
	523	}
	524	}
	525
	526	if ( formats != &format ) {
	527	// free memory if we allocated it
	528	delete [] formats;
	529	}
	530
	531	return n < nFormats ? format : wxFormatInvalid;
	532	}
	533
	534	// ----------------------------------------------------------------------------
	535	// private functions
	536	// ----------------------------------------------------------------------------
	537
	538	static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
	539	{
	540	switch ( dwEffect ) {
	541	case DROPEFFECT_COPY:
	542	return wxDragCopy;
	543
	544	case DROPEFFECT_LINK:
	545	return wxDragLink;
	546
	547	case DROPEFFECT_MOVE:
	548	return wxDragMove;
	549
	550	default:
	551	wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
	552	// fall through
	553
	554	case DROPEFFECT_NONE:
	555	return wxDragNone;
	556	}
	557	}
	558
	559	static DWORD ConvertDragResultToEffect(wxDragResult result)
	560	{
	561	switch ( result ) {
	562	case wxDragCopy:
	563	return DROPEFFECT_COPY;
	564
	565	case wxDragLink:
	566	return DROPEFFECT_LINK;
	567
	568	case wxDragMove:
	569	return DROPEFFECT_MOVE;
	570
	571	default:
	572	wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
	573	// fall through
	574
	575	case wxDragNone:
	576	return DROPEFFECT_NONE;
	577	}
	578	}
	579
	580	#endif // wxUSE_OLE && wxUSE_DRAG_AND_DROP