feat(cliprdr): advertise Preferred DropEffect alongside FileGroupDescriptorW#1301
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clintcan wants to merge 1 commit into
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feat(cliprdr): advertise Preferred DropEffect alongside FileGroupDescriptorW#1301clintcan wants to merge 1 commit into
clintcan wants to merge 1 commit into
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…riptorW `initiate_file_copy` now advertises BOTH `FileGroupDescriptorW` AND `Preferred DropEffect` (`CFSTR_PREFERREDDROPEFFECT`) in the same FormatList, and `handle_format_data_request` short-circuits a FormatDataRequest for the latter with `DROPEFFECT_COPY` (0x00000001 LE) without bothering the backend. - Added `ClipboardFormatName::PREFERRED_DROP_EFFECT = "Preferred DropEffect"`. - Added `Cliprdr::local_drop_effect_format_id` (mirrors `local_file_list_format_id` in lifecycle: set in `initiate_file_copy`, cleared on FormatListResponse::Fail and at the top of `initiate_copy`). - Picked a distinct private-range format ID (`0xC0FD`) — the wire only cares about the format *name*; the ID just needs to be locally unique so the request can be routed. No backend trait changes — the response is fixed (DROPEFFECT_COPY, matching the function's name) and served inline, so backends don't have to learn about the format. ### Why Windows Explorer pairs `CFSTR_PREFERREDDROPEFFECT` with the file formats locally; together they label the operation as a *copy*. When both are present, Explorer engages its shell file-copy machinery on paste (with native progress UI). Without `PreferredDropEffect`, Explorer falls back to a plain synchronous IStream read. ### Use case Used in https://github.com/clintcan/macrdp to deliver the standard "copying a file from the remote into local Windows Explorer" UX. The companion FD_PROGRESSUI flag (in a separate PR) is what actually triggers the native progress dialog; `PreferredDropEffect` provides the operation-semantics label Windows expects to see alongside the file descriptor for a clipboard file paste.
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initiate_file_copynow advertises bothFileGroupDescriptorWandPreferred DropEffect(CFSTR_PREFERREDDROPEFFECT) in the FormatList, andhandle_format_data_requestshort-circuits a request for the latter withDROPEFFECT_COPY(0x00000001 LE).Changes
ClipboardFormatName::PREFERRED_DROP_EFFECT = "Preferred DropEffect".Cliprdr::local_drop_effect_format_id— mirrorslocal_file_list_format_idin lifecycle (set ininitiate_file_copy, cleared onFormatListResponse::Failand at the top ofinitiate_copy).0xC0FD) — the wire only cares about the format name; the ID just needs to be locally unique so the request can be routed.DROPEFFECT_COPY, matching the function's name) and served inline, so backends don't have to learn about the format.Why
Windows Explorer pairs
CFSTR_PREFERREDDROPEFFECTwith the file formats locally; together they label the operation as a copy. When both are present, Explorer engages its shell file-copy machinery on paste (with native progress UI). WithoutPreferredDropEffect, Explorer falls back to a plain synchronousIStreamread.Use case / verification
Used in macrdp (a Rust RDP server for macOS) to deliver the standard "copy a file from the remote into local Windows Explorer" UX. Verified end-to-end on real mstsc.
The companion
FD_PROGRESSUIflag (#1299) is what actually triggers the native progress dialog;PreferredDropEffectprovides the operation-semantics label Windows expects to see alongside the file descriptor for a clipboard file paste. Either change is independently useful, but the user-visible "native progress dialog" UX requires both.Related