xwayland/selection: use one X11 window per incoming transfer

This commit introduces logic for using a new X11 window for each
incoming transfer, rather than having a global window for each selection
source.

This eliminates a whole class of bugs involving multiple concurrent
incoming transfers.

For now, we retain the outgoing transfer queue, and the selection
source-specific windows to support it. Source-specific windows are no
longer used in the incoming path, and will be removed in a future PR.

Refs #1497.

2 files changed, 14 insertions, 6 deletions

diff --git a/include/xwayland/selection.h b/include/xwayland/selection.h
index 1d8d3ec4..07659cfd 100644
--- a/include/xwayland/selection.h
+++ b/include/xwayland/selection.h
@@ -20,37 +20,43 @@ struct wlr_xwm_selection_transfer {
 	struct wl_array source_data;
 	int wl_client_fd;
 	struct wl_event_source *event_source;
+	struct wl_list link;
 
 	// when sending to x11
 	xcb_selection_request_event_t request;
-	struct wl_list outgoing_link;
 
 	// when receiving from x11
 	int property_start;
 	xcb_get_property_reply_t *property_reply;
+	xcb_window_t incoming_window;
 };
 
 struct wlr_xwm_selection {
 	struct wlr_xwm *xwm;
+
 	xcb_atom_t atom;
 	xcb_window_t window;
 	xcb_window_t owner;
 	xcb_timestamp_t timestamp;
 
-	struct wlr_xwm_selection_transfer incoming;
+	struct wl_list incoming;
 	struct wl_list outgoing;
 };
 
+struct wlr_xwm_selection_transfer *
+xwm_selection_find_incoming_transfer_by_window(
+	struct wlr_xwm_selection *selection, xcb_window_t window);
+
 void xwm_selection_transfer_remove_event_source(
 	struct wlr_xwm_selection_transfer *transfer);
 void xwm_selection_transfer_close_wl_client_fd(
 	struct wlr_xwm_selection_transfer *transfer);
 void xwm_selection_transfer_destroy_property_reply(
 	struct wlr_xwm_selection_transfer *transfer);
-void xwm_selection_transfer_init(struct wlr_xwm_selection_transfer *transfer);
-void xwm_selection_transfer_finish(struct wlr_xwm_selection_transfer *transfer);
-bool xwm_selection_transfer_get_selection_property(
-	struct wlr_xwm_selection_transfer *transfer, bool delete);
+void xwm_selection_transfer_init(struct wlr_xwm_selection_transfer *transfer,
+	struct wlr_xwm_selection *selection);
+void xwm_selection_transfer_destroy(
+	struct wlr_xwm_selection_transfer *transfer);
 
 void xwm_selection_transfer_destroy_outgoing(
 	struct wlr_xwm_selection_transfer *transfer);
diff --git a/include/xwayland/xwm.h b/include/xwayland/xwm.h
index 27b79b30..f467e107 100644
--- a/include/xwayland/xwm.h
+++ b/include/xwayland/xwm.h
@@ -103,6 +103,8 @@ struct wlr_xwm {
 	xcb_render_pictformat_t render_format_id;
 	xcb_cursor_t cursor;
 
+	// FIXME: need one per selection to simultaneously request both mimetypes,
+	// I think.
 	xcb_window_t selection_window;
 	struct wlr_xwm_selection clipboard_selection;
 	struct wlr_xwm_selection primary_selection;