Fix GitHub issue #294: Does not process CFSTR_PREFERREDDROPEFFECT on drag/drop

diff --git a/Src/DropHandler.cpp b/Src/DropHandler.cpp
index 59ce018..17adb47 100644 (file)
--- a/Src/DropHandler.cpp
+++ b/Src/DropHandler.cpp
@@ -21,13 +21,13 @@ namespace
        typedef _com_ptr_t<_com_IIID<IFileOperation, &__uuidof(IFileOperation)>> IFileOperationPtr;
        typedef _com_ptr_t<_com_IIID<IShellItem, &__uuidof(IShellItem)>> IShellItemPtr;
 
-       bool CopyFileOrFolder(const String& src, const String& dst)
+       bool CopyFileOrFolder(const String& src, const String& dst, unsigned op = FO_COPY)
        {
                std::vector<TCHAR> srcpath(src.length() + 2, 0);
                std::vector<TCHAR> dstpath(dst.length() + 2, 0);
                memcpy(&srcpath[0], src.c_str(), src.length() * sizeof(TCHAR));
                memcpy(&dstpath[0], dst.c_str(), dst.length() * sizeof(TCHAR));
-               SHFILEOPSTRUCT fileop = { 0, FO_COPY, &srcpath[0], &dstpath[0], FOF_NOCONFIRMATION, 0, 0, 0 };
+               SHFILEOPSTRUCT fileop = { 0, op, &srcpath[0], &dstpath[0], FOF_NOCONFIRMATION, 0, 0, 0 };
                return SHFileOperation(&fileop) == 0;
        }
 
@@ -146,6 +146,8 @@ namespace
 
        HRESULT GetFileItemsFromIDataObject_CF_HDROP(IDataObject *pDataObj, std::vector<String>& files)
        {
+               FORMATETC fmtetc_preferreddropeffect = { static_cast<WORD>(RegisterClipboardFormat(CFSTR_PREFERREDDROPEFFECT )), nullptr, DVASPECT_CONTENT, -1, TYMED_HGLOBAL };
+               FORMATETC fmtetc_performeddropeffect = { static_cast<WORD>(RegisterClipboardFormat(CFSTR_PERFORMEDDROPEFFECT )), nullptr, DVASPECT_CONTENT, -1, TYMED_HGLOBAL };
                FORMATETC fmtetc_cf_hdrop = { CF_HDROP, nullptr, DVASPECT_CONTENT, -1, TYMED_HGLOBAL };
                STGMEDIUM medium = { 0 };
                HRESULT hr;
@@ -155,6 +157,35 @@ namespace
                        if (hDrop != nullptr)
                        {
                                files = FilterFiles(GetDroppedFiles(hDrop));
+
+                               STGMEDIUM medium2 = {};
+                               DWORD dwDropEffect = DROPEFFECT_NONE;
+                               if (pDataObj->GetData(&fmtetc_preferreddropeffect, &medium2) == S_OK)
+                               {
+                                       dwDropEffect = *((DWORD *)GlobalLock(medium2.hGlobal));
+                                       GlobalUnlock(medium2.hGlobal);
+                                       ReleaseStgMedium(&medium2);
+
+                                       for (auto& file : files)
+                                       {
+                                               if (dwDropEffect == DROPEFFECT_COPY || dwDropEffect == DROPEFFECT_MOVE)
+                                               {
+                                                       String tmpdir = env::GetTempChildPath();
+                                                       CopyFileOrFolder(file, tmpdir, dwDropEffect == DROPEFFECT_COPY ? FO_COPY : FO_MOVE);
+                                                       file = paths::ConcatPath(tmpdir, paths::FindFileName(file));
+                                               }
+                                       }
+
+                                       STGMEDIUM medium3 = { TYMED_HGLOBAL };
+                                       medium3.hGlobal = GlobalAlloc(GMEM_MOVEABLE | GMEM_SHARE | GMEM_DISCARDABLE, sizeof(DWORD));
+                                       if (medium3.hGlobal != nullptr)
+                                       {
+                                               *((DWORD *)GlobalLock(medium3.hGlobal)) = dwDropEffect;
+                                               GlobalUnlock(medium3.hGlobal);
+                                               pDataObj->SetData(&fmtetc_performeddropeffect, &medium3, TRUE);
+                                       }
+                               }
+
                                GlobalUnlock(medium.hGlobal);
                        }
                        ReleaseStgMedium(&medium);