deskflow/src/lib/platform/MSWindowsDropTarget.cpp

/*
 * synergy -- mouse and keyboard sharing utility
 * Copyright (C) 2014-2016 Symless Ltd.
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "platform/MSWindowsDropTarget.h"

#include "base/Log.h"
#include "common/common.h"

#include <Shlobj.h>
#include <stdio.h>

void getDropData(IDataObject *pDataObject);

MSWindowsDropTarget *MSWindowsDropTarget::s_instance = NULL;

MSWindowsDropTarget::MSWindowsDropTarget() : m_refCount(1), m_allowDrop(false) {
  s_instance = this;
}

MSWindowsDropTarget::~MSWindowsDropTarget() {}

MSWindowsDropTarget &MSWindowsDropTarget::instance() {
  assert(s_instance != NULL);
  return *s_instance;
}

HRESULT
MSWindowsDropTarget::DragEnter(IDataObject *dataObject, DWORD keyState,
                               POINTL point, DWORD *effect) {
  // check if data object contain drop
  m_allowDrop = queryDataObject(dataObject);
  if (m_allowDrop) {
    getDropData(dataObject);
  }

  *effect = DROPEFFECT_NONE;

  return S_OK;
}

HRESULT
MSWindowsDropTarget::DragOver(DWORD keyState, POINTL point, DWORD *effect) {
  *effect = DROPEFFECT_NONE;

  return S_OK;
}

HRESULT
MSWindowsDropTarget::DragLeave(void) { return S_OK; }

HRESULT
MSWindowsDropTarget::Drop(IDataObject *dataObject, DWORD keyState, POINTL point,
                          DWORD *effect) {
  *effect = DROPEFFECT_NONE;

  return S_OK;
}

bool MSWindowsDropTarget::queryDataObject(IDataObject *dataObject) {
  // check if it supports CF_HDROP using a HGLOBAL
  FORMATETC fmtetc = {CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL};

  return dataObject->QueryGetData(&fmtetc) == S_OK ? true : false;
}

void MSWindowsDropTarget::setDraggingFilename(char *const filename) {
  m_dragFilename = filename;
}

std::string MSWindowsDropTarget::getDraggingFilename() {
  return m_dragFilename;
}

void MSWindowsDropTarget::clearDraggingFilename() { m_dragFilename.clear(); }

void getDropData(IDataObject *dataObject) {
  // construct a FORMATETC object
  FORMATETC fmtEtc = {CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL};
  STGMEDIUM stgMed;

  // See if the dataobject contains any DROP stored as a HGLOBAL
  if (dataObject->QueryGetData(&fmtEtc) == S_OK) {
    if (dataObject->GetData(&fmtEtc, &stgMed) == S_OK) {
      // get data here
      PVOID data = GlobalLock(stgMed.hGlobal);

      // data object global handler contains:
      // DROPFILESfilename1 filename2 two spaces as the end
      // TODO: get multiple filenames
      wchar_t *wcData = (wchar_t *)((LPBYTE)data + sizeof(DROPFILES));

      // convert wchar to char
      char *filename = new char[wcslen(wcData) + 1];
      filename[wcslen(wcData)] = '\0';
      wcstombs(filename, wcData, wcslen(wcData));

      MSWindowsDropTarget::instance().setDraggingFilename(filename);

      GlobalUnlock(stgMed.hGlobal);

      // release the data using the COM API
      ReleaseStgMedium(&stgMed);

      delete[] filename;
    }
  }
}

HRESULT __stdcall MSWindowsDropTarget::QueryInterface(REFIID iid,
                                                      void **object) {
  if (iid == IID_IDropTarget || iid == IID_IUnknown) {
    AddRef();
    *object = this;
    return S_OK;
  } else {
    *object = 0;
    return E_NOINTERFACE;
  }
}

ULONG __stdcall MSWindowsDropTarget::AddRef(void) {
  return InterlockedIncrement(&m_refCount);
}

ULONG __stdcall MSWindowsDropTarget::Release(void) {
  LONG count = InterlockedDecrement(&m_refCount);

  if (count == 0) {
    delete this;
    return 0;
  } else {
    return count;
  }
}