[Spice-devel] [PATCH spice 12/17] spicec-x11: Force processing of ownerchange event when releasing the cb

[Arnon Gilboa]

Hans de Goede wrote:
> Make sure we process the XFixesSetSelectionOwnerNotify event caused by
> us setting the clipboard owner to none, directly after setting the owner
> to none. Otherwise we may end up changing the clipboard owner to none, after
> it has already been re-owned because the XFixesSetSelectionOwnerNotify event
> to owner none is event is still pending when we set the new owner, and
> then changes the owner back to none once processed messing up our clipboard
> ownership state tracking.
>
> I saw this happening when doing copy twice in succession inside the guest.
> ---
>  client/red_client.cpp       |    3 +--
>  client/windows/platform.cpp |    1 +
>  client/x11/platform.cpp     |   13 +++++++++++++
>  3 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/client/red_client.cpp b/client/red_client.cpp
> index a022499..8e7dfe0 100644
> --- a/client/red_client.cpp
> +++ b/client/red_client.cpp
> @@ -1133,12 +1133,11 @@ void RedClient::dispatch_agent_message(VDAgentMessage* msg, void* data)
>          break;
>      case VD_AGENT_CLIPBOARD_RELEASE:
>          if (Platform::get_clipboard_owner() != Platform::owner_guest) {
> -            LOG_WARN("received clipboard release from guest while clipboard is not owned by guest");
> +            LOG_INFO("received clipboard release from guest while clipboard is not owned by guest");
>              break;
>          }
>  
>          Platform::on_clipboard_release();
> -        Platform::set_clipboard_owner(Platform::owner_none);
>          break;
>      default:
>          DBG(0, "Unsupported message type %u size %u", msg->type, msg->size);
> diff --git a/client/windows/platform.cpp b/client/windows/platform.cpp
> index db47079..580a40a 100644
> --- a/client/windows/platform.cpp
> +++ b/client/windows/platform.cpp
> @@ -1011,6 +1011,7 @@ bool Platform::on_clipboard_request(uint32_t type)
>  void Platform::on_clipboard_release()
>  {
>      SetEvent(clipboard_event);
> +    set_clipboard_owner(owner_none);
>  }
>  
>  static bool has_console = false;
> diff --git a/client/x11/platform.cpp b/client/x11/platform.cpp
> index ea2558d..75b34c6 100644
> --- a/client/x11/platform.cpp
> +++ b/client/x11/platform.cpp
> @@ -3342,5 +3342,18 @@ bool Platform::on_clipboard_request(uint32_t type)
>  
>  void Platform::on_clipboard_release()
>  {
> +    XEvent event;
> +
>      XSetSelectionOwner(x_display, clipboard_prop, None, CurrentTime);
> +    /* Make sure we process the XFixesSetSelectionOwnerNotify event caused
> +       by this, so we don't end up changing the clipboard owner to none, after
> +       it has already been re-owned because this event is still pending. */
> +    XSync(x_display, False);
> +    while (XCheckTypedEvent(x_display,
> +                            XFixesSelectionNotify + xfixes_event_base,
> +                            &event))
> +        root_win_proc(event);
> +
> +    /* Note no need to do a set_clipboard_owner(owner_none) here, as that is
> +       already done by processing the XFixesSetSelectionOwnerNotify event. */
>  }
>   
Ack