[PATCH weston v2 3/3] compositor-x11: remove manual mouse button grab/ungrab

[Benoit Gschwind]

In current compositor-x11, the mouse buttons are grabbed and ungrabbed
manually that may produce weird cases like starting a grab while the
buttons are already released, due to asynchronous X11 events dispatching.

The patch avoid the issue by using the better passive button grab, that
automatically grab buttons as soon as they occur. The passive grab
include an automatic ungrab when all mouse button are released.

This probably fix some mysterious bugs.

Signed-off-by: Benoit Gschwind <gschwind at gnu-log.net>
---
 src/compositor-x11.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/src/compositor-x11.c b/src/compositor-x11.c
index 8a65d48..c66c5f8 100644
--- a/src/compositor-x11.c
+++ b/src/compositor-x11.c
@@ -882,6 +882,19 @@ x11_backend_create_output(struct x11_backend *b, int x, int y,
 
 	x11_output_set_wm_protocols(b, output);
 
+	/* Automatically grab and ungrab mouse buttons */
+	xcb_grab_button(b->conn, 0, output->window,
+			XCB_EVENT_MASK_BUTTON_PRESS |
+			XCB_EVENT_MASK_BUTTON_RELEASE |
+			XCB_EVENT_MASK_POINTER_MOTION |
+			XCB_EVENT_MASK_ENTER_WINDOW |
+			XCB_EVENT_MASK_LEAVE_WINDOW,
+			XCB_GRAB_MODE_ASYNC,
+			XCB_GRAB_MODE_ASYNC,
+			output->window, XCB_CURSOR_NONE,
+			XCB_BUTTON_INDEX_ANY,
+			XCB_MOD_MASK_ANY);
+
 	xcb_map_window(b->conn, output->window);
 
 	if (fullscreen)
@@ -1053,20 +1066,6 @@ x11_backend_deliver_button_event(struct x11_backend *b,
 	if (!output)
 		return;
 
-	if (is_button_pressed)
-		xcb_grab_pointer(b->conn, 0, output->window,
-				 XCB_EVENT_MASK_BUTTON_PRESS |
-				 XCB_EVENT_MASK_BUTTON_RELEASE |
-				 XCB_EVENT_MASK_POINTER_MOTION |
-				 XCB_EVENT_MASK_ENTER_WINDOW |
-				 XCB_EVENT_MASK_LEAVE_WINDOW,
-				 XCB_GRAB_MODE_ASYNC,
-				 XCB_GRAB_MODE_ASYNC,
-				 output->window, XCB_CURSOR_NONE,
-				 button_event->time);
-	else
-		xcb_ungrab_pointer(b->conn, button_event->time);
-
 	if (!b->has_xkb)
 		update_xkb_state_from_core(b, button_event->state);
 
-- 
2.7.3