used a hidden drop window to get drag filename

src/lib/platform/MSWindowsDropTarget.cpp

@@ -0,0 +1,178 @@
+/*
+ * synergy -- mouse and keyboard sharing utility
+ * Copyright (C) 2014 Bolton Software 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 COPYING 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 <stdio.h>
+#include <Shlobj.h>
+
+void getDropData(IDataObject *pDataObject);
+
+CMSWindowsDropTarget* CMSWindowsDropTarget::s_instance = NULL;
+
+CMSWindowsDropTarget::CMSWindowsDropTarget() :
+	m_refCount(1),
+	m_allowDrop(false)
+{
+	s_instance = this;
+}
+
+CMSWindowsDropTarget::~CMSWindowsDropTarget()
+{
+}
+
+CMSWindowsDropTarget&
+CMSWindowsDropTarget::instance()
+{
+	assert(s_instance != NULL);
+	return *s_instance;
+}
+
+HRESULT
+CMSWindowsDropTarget::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
+CMSWindowsDropTarget::DragOver(DWORD keyState, POINTL point, DWORD* effect)
+{
+	*effect = DROPEFFECT_NONE;
+
+	return S_OK;
+}
+
+HRESULT
+CMSWindowsDropTarget::DragLeave(void)
+{
+	return S_OK;
+}
+
+HRESULT
+CMSWindowsDropTarget::Drop(IDataObject* dataObject, DWORD keyState, POINTL point, DWORD* effect)
+{
+	*effect = DROPEFFECT_NONE;
+
+	return S_OK;
+}
+
+bool
+CMSWindowsDropTarget::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
+CMSWindowsDropTarget::setDraggingFilename(char* const filename)
+{
+	m_dragFilename = filename;
+}
+
+std::string
+CMSWindowsDropTarget::getDraggingFilename()
+{
+	return m_dragFilename;
+}
+
+void
+CMSWindowsDropTarget::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));
+
+			CMSWindowsDropTarget::instance().setDraggingFilename(filename);
+			
+			GlobalUnlock(stgMed.hGlobal);
+
+			// release the data using the COM API
+			ReleaseStgMedium(&stgMed);
+
+			delete[] filename;
+		}
+	}
+}
+
+HRESULT __stdcall
+CMSWindowsDropTarget::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
+CMSWindowsDropTarget::AddRef(void)
+{
+	return InterlockedIncrement(&m_refCount);
+}
+
+ULONG __stdcall
+CMSWindowsDropTarget::Release(void)
+{
+	LONG count = InterlockedDecrement(&m_refCount);
+		
+	if (count == 0) {
+		delete this;
+		return 0;
+	}
+	else {
+		return count;
+	}
+}