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 inline DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction);

    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
// 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)
{
  if (defaultAction == wxDragCopy)
    return flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
  return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
}

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
//           [out]DWORD       *pdwEffect    : effect flag
// 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()))
                    )
                 );

    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
//           [out]LPDWORD pdwEffect       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()));
    }
    else {
        // can't accept data anyhow normally
        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)
                 );

    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?
//           [ouy]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 );

    // by default, nothing happens
    *pdwEffect = DROPEFFECT_NONE;

    // 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()));
        rc = m_pTarget->OnData(pt.x, pt.y, rc);
        if ( wxIsDragResultOk(rc) ) {
            // operation succeeded
            *pdwEffect = ConvertDragResultToEffect(rc);
        }
        //else: *pdwEffect is already DROPEFFECT_NONE
    }
    //else: OnDrop() returned false, no need to copy data

    // 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 inline DWORD GetDropEffect(DWORD flags, wxDragResult defaultAction);
	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	// Notes : We do "move" normally and "copy" if <Ctrl> is pressed,
	105	// which is the standard behaviour (currently there is no
	106	// way to redefine it)
	107	DWORD wxIDropTarget::GetDropEffect(DWORD flags, wxDragResult defaultAction)
	108	{
	109	if (defaultAction == wxDragCopy)
	110	return flags & MK_SHIFT ? DROPEFFECT_MOVE : DROPEFFECT_COPY;
	111	return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
	112	}
	113
	114	wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
	115	{
	116	m_pTarget = pTarget;
	117	m_pIDataObject = NULL;
	118	}
	119
	120	wxIDropTarget::~wxIDropTarget()
	121	{
	122	}
	123
	124	BEGIN_IID_TABLE(wxIDropTarget)
	125	ADD_IID(Unknown)
	126	ADD_IID(DropTarget)
	127	END_IID_TABLE;
	128
	129	IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
	130
	131	// Name : wxIDropTarget::DragEnter
	132	// Purpose : Called when the mouse enters the window (dragging something)
	133	// Returns : S_OK
	134	// Params : [in] IDataObject *pIDataSource : source data
	135	// [in] DWORD grfKeyState : kbd & mouse state
	136	// [in] POINTL pt : mouse coordinates
	137	// [out]DWORD *pdwEffect : effect flag
	138	// Notes :
	139	STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
	140	DWORD grfKeyState,
	141	POINTL pt,
	142	DWORD *pdwEffect)
	143	{
	144	wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
	145
	146	wxASSERT_MSG( m_pIDataObject == NULL,
	147	_T("drop target must have data object") );
	148
	149	// show the list of formats supported by the source data object for the
	150	// debugging purposes, this is quite useful sometimes - please don't remove
	151	#if 0
	152	IEnumFORMATETC *penumFmt;
	153	if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
	154	{
	155	FORMATETC fmt;
	156	while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
	157	{
	158	wxLogDebug(_T("Drop source supports format %s"),
	159	wxDataObject::GetFormatName(fmt.cfFormat));
	160	}
	161
	162	penumFmt->Release();
	163	}
	164	else
	165	{
	166	wxLogLastError(_T("IDataObject::EnumFormatEtc"));
	167	}
	168	#endif // 0
	169
	170	if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
	171	// we don't accept this kind of data
	172	*pdwEffect = DROPEFFECT_NONE;
	173
	174	return S_OK;
	175	}
	176
	177	// get hold of the data object
	178	m_pIDataObject = pIDataSource;
	179	m_pIDataObject->AddRef();
	180
	181	// we need client coordinates to pass to wxWin functions
	182	if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
	183	{
	184	wxLogLastError(wxT("ScreenToClient"));
	185	}
	186
	187	// give some visual feedback
	188	*pdwEffect = ConvertDragResultToEffect(
	189	m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
	190	GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()))
	191	)
	192	);
	193
	194	return S_OK;
	195	}
	196
	197	// Name : wxIDropTarget::DragOver
	198	// Purpose : Indicates that the mouse was moved inside the window represented
	199	// by this drop target.
	200	// Returns : S_OK
	201	// Params : [in] DWORD grfKeyState kbd & mouse state
	202	// [in] POINTL pt mouse coordinates
	203	// [out]LPDWORD pdwEffect effect flag
	204	// Notes : We're called on every WM_MOUSEMOVE, so this function should be
	205	// very efficient.
	206	STDMETHODIMP wxIDropTarget::DragOver(DWORD grfKeyState,
	207	POINTL pt,
	208	LPDWORD pdwEffect)
	209	{
	210	// there are too many of them... wxLogDebug("IDropTarget::DragOver");
	211
	212	wxDragResult result;
	213	if ( m_pIDataObject ) {
	214	result = ConvertDragEffectToResult(
	215	GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
	216	}
	217	else {
	218	// can't accept data anyhow normally
	219	result = wxDragNone;
	220	}
	221
	222	// we need client coordinates to pass to wxWin functions
	223	if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
	224	{
	225	wxLogLastError(wxT("ScreenToClient"));
	226	}
	227
	228	*pdwEffect = ConvertDragResultToEffect(
	229	m_pTarget->OnDragOver(pt.x, pt.y, result)
	230	);
	231
	232	return S_OK;
	233	}
	234
	235	// Name : wxIDropTarget::DragLeave
	236	// Purpose : Informs the drop target that the operation has left its window.
	237	// Returns : S_OK
	238	// Notes : good place to do any clean-up
	239	STDMETHODIMP wxIDropTarget::DragLeave()
	240	{
	241	wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragLeave"));
	242
	243	// remove the UI feedback
	244	m_pTarget->OnLeave();
	245
	246	// release the held object
	247	RELEASE_AND_NULL(m_pIDataObject);
	248
	249	return S_OK;
	250	}
	251
	252	// Name : wxIDropTarget::Drop
	253	// Purpose : Instructs the drop target to paste data that was just now
	254	// dropped on it.
	255	// Returns : S_OK
	256	// Params : [in] IDataObject *pIDataSource the data to paste
	257	// [in] DWORD grfKeyState kbd & mouse state
	258	// [in] POINTL pt where the drop occurred?
	259	// [ouy]DWORD *pdwEffect operation effect
	260	// Notes :
	261	STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
	262	DWORD grfKeyState,
	263	POINTL pt,
	264	DWORD *pdwEffect)
	265	{
	266	wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
	267
	268	// TODO I don't know why there is this parameter, but so far I assume
	269	// that it's the same we've already got in DragEnter
	270	wxASSERT( m_pIDataObject == pIDataSource );
	271
	272	// by default, nothing happens
	273	*pdwEffect = DROPEFFECT_NONE;
	274
	275	// we need client coordinates to pass to wxWin functions
	276	if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
	277	{
	278	wxLogLastError(wxT("ScreenToClient"));
	279	}
	280
	281	// first ask the drop target if it wants data
	282	if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
	283	// it does, so give it the data source
	284	m_pTarget->SetDataSource(pIDataSource);
	285
	286	// and now it has the data
	287	wxDragResult rc = ConvertDragEffectToResult(
	288	GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction()));
	289	rc = m_pTarget->OnData(pt.x, pt.y, rc);
	290	if ( wxIsDragResultOk(rc) ) {
	291	// operation succeeded
	292	*pdwEffect = ConvertDragResultToEffect(rc);
	293	}
	294	//else: *pdwEffect is already DROPEFFECT_NONE
	295	}
	296	//else: OnDrop() returned false, no need to copy data
	297
	298	// release the held object
	299	RELEASE_AND_NULL(m_pIDataObject);
	300
	301	return S_OK;
	302	}
	303
	304	// ============================================================================
	305	// wxDropTarget implementation
	306	// ============================================================================
	307
	308	// ----------------------------------------------------------------------------
	309	// ctor/dtor
	310	// ----------------------------------------------------------------------------
	311
	312	wxDropTarget::wxDropTarget(wxDataObject *dataObj)
	313	: wxDropTargetBase(dataObj)
	314	{
	315	// create an IDropTarget implementation which will notify us about d&d
	316	// operations.
	317	m_pIDropTarget = new wxIDropTarget(this);
	318	m_pIDropTarget->AddRef();
	319	}
	320
	321	wxDropTarget::~wxDropTarget()
	322	{
	323	ReleaseInterface(m_pIDropTarget);
	324	}
	325
	326	// ----------------------------------------------------------------------------
	327	// [un]register drop handler
	328	// ----------------------------------------------------------------------------
	329
	330	bool wxDropTarget::Register(WXHWND hwnd)
	331	{
	332	// FIXME
	333	// RegisterDragDrop not available on Windows CE >= 400?
	334	// Or maybe we can dynamically load them from ceshell.dll
	335	// or similar.
	336	#if defined(__WXWINCE__) && _WIN32_WCE >= 400
	337	wxUnusedVar(hwnd);
	338	return false;
	339	#else
	340	HRESULT hr;
	341
	342	// May exist in later WinCE versions
	343	#ifndef __WXWINCE__
	344	hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
	345	if ( FAILED(hr) ) {
	346	wxLogApiError(wxT("CoLockObjectExternal"), hr);
	347	return false;
	348	}
	349	#endif
	350
	351	hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
	352	if ( FAILED(hr) ) {
	353	// May exist in later WinCE versions
	354	#ifndef __WXWINCE__
	355	::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
	356	#endif
	357	wxLogApiError(wxT("RegisterDragDrop"), hr);
	358	return false;
	359	}
	360
	361	// we will need the window handle for coords transformation later
	362	m_pIDropTarget->SetHwnd((HWND)hwnd);
	363
	364	return true;
	365	#endif
	366	}
	367
	368	void wxDropTarget::Revoke(WXHWND hwnd)
	369	{
	370	#if defined(__WXWINCE__) && _WIN32_WCE >= 400
	371	// Not available, see note above
	372	wxUnusedVar(hwnd);
	373	#else
	374	HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
	375
	376	if ( FAILED(hr) ) {
	377	wxLogApiError(wxT("RevokeDragDrop"), hr);
	378	}
	379
	380	// May exist in later WinCE versions
	381	#ifndef __WXWINCE__
	382	::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
	383	#endif
	384
	385	m_pIDropTarget->SetHwnd(0);
	386	#endif
	387	}
	388
	389	// ----------------------------------------------------------------------------
	390	// base class pure virtuals
	391	// ----------------------------------------------------------------------------
	392
	393	// OnDrop() is called only if we previously returned true from
	394	// IsAcceptedData(), so no need to check anything here
	395	bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
	396	{
	397	return true;
	398	}
	399
	400	// copy the data from the data source to the target data object
	401	bool wxDropTarget::GetData()
	402	{
	403	wxDataFormat format = GetSupportedFormat(m_pIDataSource);
	404	if ( format == wxDF_INVALID ) {
	405	// this is strange because IsAcceptedData() succeeded previously!
	406	wxFAIL_MSG(wxT("strange - did supported formats list change?"));
	407
	408	return false;
	409	}
	410
	411	STGMEDIUM stm;
	412	FORMATETC fmtMemory;
	413	fmtMemory.cfFormat = format;
	414	fmtMemory.ptd = NULL;
	415	fmtMemory.dwAspect = DVASPECT_CONTENT;
	416	fmtMemory.lindex = -1;
	417	fmtMemory.tymed = TYMED_HGLOBAL; // TODO to add other media
	418
	419	bool rc = false;
	420
	421	HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
	422	if ( SUCCEEDED(hr) ) {
	423	IDataObject *dataObject = m_dataObject->GetInterface();
	424
	425	hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
	426	if ( SUCCEEDED(hr) ) {
	427	rc = true;
	428	}
	429	else {
	430	wxLogApiError(wxT("IDataObject::SetData()"), hr);
	431	}
	432	}
	433	else {
	434	wxLogApiError(wxT("IDataObject::GetData()"), hr);
	435	}
	436
	437	return rc;
	438	}
	439
	440	// ----------------------------------------------------------------------------
	441	// callbacks used by wxIDropTarget
	442	// ----------------------------------------------------------------------------
	443
	444	// we need a data source, so wxIDropTarget gives it to us using this function
	445	void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
	446	{
	447	m_pIDataSource = pIDataSource;
	448	}
	449
	450	// determine if we accept data of this type
	451	bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
	452	{
	453	return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
	454	}
	455
	456	// ----------------------------------------------------------------------------
	457	// helper functions
	458	// ----------------------------------------------------------------------------
	459
	460	wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
	461	{
	462	// this strucutre describes a data of any type (first field will be
	463	// changing) being passed through global memory block.
	464	static FORMATETC s_fmtMemory = {
	465	0,
	466	NULL,
	467	DVASPECT_CONTENT,
	468	-1,
	469	TYMED_HGLOBAL // TODO is it worth supporting other tymeds here?
	470	};
	471
	472	// get the list of supported formats
	473	size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
	474	wxDataFormat format;
	475	wxDataFormat *formats;
	476	formats = nFormats == 1 ? &format : new wxDataFormat[nFormats];
	477
	478	m_dataObject->GetAllFormats(formats, wxDataObject::Set);
	479
	480	// cycle through all supported formats
	481	size_t n;
	482	for ( n = 0; n < nFormats; n++ ) {
	483	s_fmtMemory.cfFormat = formats[n];
	484
	485	// NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
	486	// for file drag and drop (format == CF_HDROP)
	487	if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
	488	format = formats[n];
	489
	490	break;
	491	}
	492	}
	493
	494	if ( formats != &format ) {
	495	// free memory if we allocated it
	496	delete [] formats;
	497	}
	498
	499	return n < nFormats ? format : wxFormatInvalid;
	500	}
	501
	502	// ----------------------------------------------------------------------------
	503	// private functions
	504	// ----------------------------------------------------------------------------
	505
	506	static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
	507	{
	508	switch ( dwEffect ) {
	509	case DROPEFFECT_COPY:
	510	return wxDragCopy;
	511
	512	case DROPEFFECT_LINK:
	513	return wxDragLink;
	514
	515	case DROPEFFECT_MOVE:
	516	return wxDragMove;
	517
	518	default:
	519	wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
	520	// fall through
	521
	522	case DROPEFFECT_NONE:
	523	return wxDragNone;
	524	}
	525	}
	526
	527	static DWORD ConvertDragResultToEffect(wxDragResult result)
	528	{
	529	switch ( result ) {
	530	case wxDragCopy:
	531	return DROPEFFECT_COPY;
	532
	533	case wxDragLink:
	534	return DROPEFFECT_LINK;
	535
	536	case wxDragMove:
	537	return DROPEFFECT_MOVE;
	538
	539	default:
	540	wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
	541	// fall through
	542
	543	case wxDragNone:
	544	return DROPEFFECT_NONE;
	545	}
	546	}
	547
	548	#endif // wxUSE_OLE && wxUSE_DRAG_AND_DROP