From: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
On the client side, whenever the grab owner changes (and the clipboard
was previously grabbed), spice-gtk sends a clipboard release followed
immediately by a new grab. But some clipboard managers on the remote
side react to clipboard release events by taking a clipboard grab,
presumably to avoid empty clipboards.
The two grabs, coming from the client and from the remote sides, will
race in both directions, which may confuse the client & remote side,
as both believe the other side is the current grab owner, and thus
further clipboard data requests are likely to fail.
Let's avoid sending a release event when re-grabing.
The race described above may still happen in other rare circunstances,
and will require a protocol change. To avoid the conflict, a discussed
solution could use a clipboard serial number.
Tested with current linux & windows vdagent. Looking at earlier
version of the code, it doesn't seem like subsequent grabs will be
treated as an error.
Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
---
src/spice-gtk-session.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/src/spice-gtk-session.c b/src/spice-gtk-session.c
index b48f92a..0e748b6 100644
--- a/src/spice-gtk-session.c
+++ b/src/spice-gtk-session.c
@@ -569,8 +569,7 @@ static void clipboard_get_targets(GtkClipboard *clipboard,
g_return_if_fail(selection != -1);
if (s->clip_grabbed[selection]) {
- SPICE_DEBUG("Clipboard is already grabbed, ignoring %d atoms", n_atoms);
- return;
+ SPICE_DEBUG("Clipboard is already grabbed, re-grab: %d atoms", n_atoms);
}
/* Set all Atoms that matches our current protocol implementation */
@@ -652,18 +651,14 @@ static void clipboard_owner_change(GtkClipboard *clipboard,
return;
}
- /* In case we sent a grab to the agent, we need to release it now as
- * previous clipboard data should not be reachable anymore */
- if (s->clip_grabbed[selection]) {
- s->clip_grabbed[selection] = FALSE;
- if (spice_main_channel_agent_test_capability(s->main, VD_AGENT_CAP_CLIPBOARD_BY_DEMAND)) {
- spice_main_channel_clipboard_selection_release(s->main, selection);
- }
- }
-
- /* We are mostly interested when owner has changed in which case
- * we would like to let agent know about new clipboard data. */
if (event->reason != GDK_OWNER_CHANGE_NEW_OWNER) {
+ if (s->clip_grabbed[selection]) {
+ /* grab was sent to the agent, so release it */
+ s->clip_grabbed[selection] = FALSE;
+ if (spice_main_channel_agent_test_capability(s->main, VD_AGENT_CAP_CLIPBOARD_BY_DEMAND)) {
+ spice_main_channel_clipboard_selection_release(s->main, selection);
+ }
+ }
s->clip_hasdata[selection] = FALSE;
return;
}
--
2.21.0.4.g36eb1cb9cf
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