Add cancel function to grab interfaces

A grab can potentially allocate memory and would normally end the grab
itself, freeing the allocated memory in the process. However at in some
situations the compositor may want to abort a grab. The grab owner still
needs to free some memory and abort the grab properly. To do this a new
function 'cancel' is introduced in all the grab interfaces instructing
the grabs owner to abort the grab.

This patch also hooks up grab cancelling to seat device releasing and
when the compositor looses focus, which would potentially leak memory
before.

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>

src/bindings.c

@@ -210,9 +210,20 @@ binding_modifiers(struct weston_keyboard_grab *grab, uint32_t serial,
 	}
 }
 
+static void
+binding_cancel(struct weston_keyboard_grab *grab)
+{
+	struct binding_keyboard_grab *binding_grab =
+		container_of(grab, struct binding_keyboard_grab, grab);
+
+	weston_keyboard_end_grab(grab->keyboard);
+	free(binding_grab);
+}
+
 static const struct weston_keyboard_grab_interface binding_grab = {
 	binding_key,
 	binding_modifiers,
+	binding_cancel,
 };
 
 static void

src/compositor.h

@@ -240,6 +240,7 @@ struct weston_pointer_grab_interface {
 	void (*motion)(struct weston_pointer_grab *grab, uint32_t time);
 	void (*button)(struct weston_pointer_grab *grab,
 		       uint32_t time, uint32_t button, uint32_t state);
+	void (*cancel)(struct weston_pointer_grab *grab);
 };
 
 struct weston_pointer_grab {
@@ -254,6 +255,7 @@ struct weston_keyboard_grab_interface {
 	void (*modifiers)(struct weston_keyboard_grab *grab, uint32_t serial,
 			  uint32_t mods_depressed, uint32_t mods_latched,
 			  uint32_t mods_locked, uint32_t group);
+	void (*cancel)(struct weston_keyboard_grab *grab);
 };
 
 struct weston_keyboard_grab {
@@ -276,6 +278,7 @@ struct weston_touch_grab_interface {
 			int touch_id,
 			wl_fixed_t sx,
 			wl_fixed_t sy);
+	void (*cancel)(struct weston_touch_grab *grab);
 };
 
 struct weston_touch_grab {

src/data-device.c

@@ -344,10 +344,23 @@ drag_grab_button(struct weston_pointer_grab *grab,
 	}
 }
 
+static void
+drag_grab_cancel(struct weston_pointer_grab *grab)
+{
+	struct weston_drag *drag =
+		container_of(grab, struct weston_drag, grab);
+
+	if (drag->data_source)
+		wl_list_remove(&drag->data_source_listener.link);
+
+	data_device_end_drag_grab(drag);
+}
+
 static const struct weston_pointer_grab_interface drag_grab_interface = {
 	drag_grab_focus,
 	drag_grab_motion,
 	drag_grab_button,
+	drag_grab_cancel,
 };
 
 static void

src/input.c

@@ -162,11 +162,17 @@ default_grab_button(struct weston_pointer_grab *grab,
 	}
 }
 
+static void
+default_grab_pointer_cancel(struct weston_pointer_grab *grab)
+{
+}
+
 static const struct weston_pointer_grab_interface
 				default_pointer_grab_interface = {
 	default_grab_focus,
 	default_grab_motion,
-	default_grab_button
+	default_grab_button,
+	default_grab_pointer_cancel,
 };
 
 static void
@@ -225,10 +231,16 @@ default_grab_touch_motion(struct weston_touch_grab *grab, uint32_t time,
 	}
 }
 
+static void
+default_grab_touch_cancel(struct weston_touch_grab *grab)
+{
+}
+
 static const struct weston_touch_grab_interface default_touch_grab_interface = {
 	default_grab_touch_down,
 	default_grab_touch_up,
-	default_grab_touch_motion
+	default_grab_touch_motion,
+	default_grab_touch_cancel,
 };
 
 static void
@@ -329,10 +341,16 @@ default_grab_modifiers(struct weston_keyboard_grab *grab, uint32_t serial,
 	}
 }
 
+static void
+default_grab_keyboard_cancel(struct weston_keyboard_grab *grab)
+{
+}
+
 static const struct weston_keyboard_grab_interface
 				default_keyboard_grab_interface = {
 	default_grab_key,
 	default_grab_modifiers,
+	default_grab_keyboard_cancel,
 };
 
 static void
@@ -601,6 +619,12 @@ weston_keyboard_end_grab(struct weston_keyboard *keyboard)
 	keyboard->grab = &keyboard->default_grab;
 }
 
+static void
+weston_keyboard_cancel_grab(struct weston_keyboard *keyboard)
+{
+	keyboard->grab->interface->cancel(keyboard->grab);
+}
+
 WL_EXPORT void
 weston_pointer_start_grab(struct weston_pointer *pointer,
 			  struct weston_pointer_grab *grab)
@@ -617,6 +641,12 @@ weston_pointer_end_grab(struct weston_pointer *pointer)
 	pointer->grab->interface->focus(pointer->grab);
 }
 
+static void
+weston_pointer_cancel_grab(struct weston_pointer *pointer)
+{
+	pointer->grab->interface->cancel(pointer->grab);
+}
+
 WL_EXPORT void
 weston_touch_start_grab(struct weston_touch *touch, struct weston_touch_grab *grab)
 {
@@ -630,6 +660,12 @@ weston_touch_end_grab(struct weston_touch *touch)
 	touch->grab = &touch->default_grab;
 }
 
+static void
+weston_touch_cancel_grab(struct weston_touch *touch)
+{
+	touch->grab->interface->cancel(touch->grab);
+}
+
 WL_EXPORT void
 weston_pointer_clamp(struct weston_pointer *pointer, wl_fixed_t *fx, wl_fixed_t *fy)
 {
@@ -1139,10 +1175,7 @@ notify_keyboard_focus_out(struct weston_seat *seat)
 	}
 
 	weston_keyboard_set_focus(keyboard, NULL);
-	/* FIXME: We really need keyboard grab cancel here to
+	weston_keyboard_cancel_grab(keyboard);
-	 * let the grab shut down properly.  As it is we leak
-	 * the grab data. */
-	weston_keyboard_end_grab(keyboard);
 }
 
 WL_EXPORT void
@@ -1798,6 +1831,7 @@ weston_seat_release_keyboard(struct weston_seat *seat)
 	seat->keyboard_device_count--;
 	if (seat->keyboard_device_count == 0) {
 		weston_keyboard_set_focus(seat->keyboard, NULL);
+		weston_keyboard_cancel_grab(seat->keyboard);
 		seat_send_updated_caps(seat);
 	}
 }
@@ -1835,6 +1869,7 @@ weston_seat_release_pointer(struct weston_seat *seat)
 		weston_pointer_set_focus(pointer, NULL,
 					 wl_fixed_from_int(0),
 					 wl_fixed_from_int(0));
+		weston_pointer_cancel_grab(pointer);
 
 		if (pointer->sprite)
 			pointer_unmap_sprite(pointer);
@@ -1872,6 +1907,7 @@ weston_seat_release_touch(struct weston_seat *seat)
 	seat->touch_device_count--;
 	if (seat->touch_device_count == 0) {
 		weston_touch_set_focus(seat, NULL);
+		weston_touch_cancel_grab(seat->touch);
 		seat_send_updated_caps(seat);
 	}
 }

src/shell.c

@@ -1162,10 +1162,22 @@ touch_move_grab_motion(struct weston_touch_grab *grab, uint32_t time,
 	weston_compositor_schedule_repaint(es->compositor);
 }
 
+static void
+touch_move_grab_cancel(struct weston_touch_grab *grab)
+{
+	struct weston_touch_move_grab *move =
+		(struct weston_touch_move_grab *) container_of(
+			grab, struct shell_touch_grab, grab);
+
+	shell_touch_grab_end(&move->base);
+	free(move);
+}
+
 static const struct weston_touch_grab_interface touch_move_grab_interface = {
 	touch_move_grab_down,
 	touch_move_grab_up,
 	touch_move_grab_motion,
+	touch_move_grab_cancel,
 };
 
 static int
@@ -1236,10 +1248,21 @@ move_grab_button(struct weston_pointer_grab *grab,
 	}
 }
 
+static void
+move_grab_cancel(struct weston_pointer_grab *grab)
+{
+	struct shell_grab *shell_grab =
+		container_of(grab, struct shell_grab, grab);
+
+	shell_grab_end(shell_grab);
+	free(grab);
+}
+
 static const struct weston_pointer_grab_interface move_grab_interface = {
 	noop_grab_focus,
 	move_grab_motion,
 	move_grab_button,
+	move_grab_cancel,
 };
 
 static int
@@ -1366,10 +1389,20 @@ resize_grab_button(struct weston_pointer_grab *grab,
 	}
 }
 
+static void
+resize_grab_cancel(struct weston_pointer_grab *grab)
+{
+	struct weston_resize_grab *resize = (struct weston_resize_grab *) grab;
+
+	shell_grab_end(&resize->base);
+	free(grab);
+}
+
 static const struct weston_pointer_grab_interface resize_grab_interface = {
 	noop_grab_focus,
 	resize_grab_motion,
 	resize_grab_button,
+	resize_grab_cancel,
 };
 
 /*
@@ -1498,10 +1531,20 @@ busy_cursor_grab_button(struct weston_pointer_grab *base,
 	}
 }
 
+static void
+busy_cursor_grab_cancel(struct weston_pointer_grab *base)
+{
+	struct shell_grab *grab = (struct shell_grab *) base;
+
+	shell_grab_end(grab);
+	free(grab);
+}
+
 static const struct weston_pointer_grab_interface busy_cursor_grab_interface = {
 	busy_cursor_grab_focus,
 	busy_cursor_grab_motion,
 	busy_cursor_grab_button,
+	busy_cursor_grab_cancel,
 };
 
 static void
@@ -2267,10 +2310,17 @@ popup_grab_button(struct weston_pointer_grab *grab,
 		shseat->popup_grab.initial_up = 1;
 }
 
+static void
+popup_grab_cancel(struct weston_pointer_grab *grab)
+{
+	popup_grab_end(grab->pointer);
+}
+
 static const struct weston_pointer_grab_interface popup_grab_interface = {
 	popup_grab_focus,
 	popup_grab_motion,
 	popup_grab_button,
+	popup_grab_cancel,
 };
 
 static void
@@ -3114,10 +3164,21 @@ rotate_grab_button(struct weston_pointer_grab *grab,
 	}
 }
 
+static void
+rotate_grab_cancel(struct weston_pointer_grab *grab)
+{
+	struct rotate_grab *rotate =
+		container_of(grab, struct rotate_grab, base.grab);
+
+	shell_grab_end(&rotate->base);
+	free(rotate);
+}
+
 static const struct weston_pointer_grab_interface rotate_grab_interface = {
 	noop_grab_focus,
 	rotate_grab_motion,
 	rotate_grab_button,
+	rotate_grab_cancel,
 };
 
 static void
@@ -4349,9 +4410,18 @@ switcher_modifier(struct weston_keyboard_grab *grab, uint32_t serial,
 		switcher_destroy(switcher);
 }
 
+static void
+switcher_cancel(struct weston_keyboard_grab *grab)
+{
+	struct switcher *switcher = container_of(grab, struct switcher, grab);
+
+	switcher_destroy(switcher);
+}
+
 static const struct weston_keyboard_grab_interface switcher_grab = {
 	switcher_key,
 	switcher_modifier,
+	switcher_cancel,
 };
 
 static void
@@ -4505,9 +4575,19 @@ debug_binding_modifiers(struct weston_keyboard_grab *grab, uint32_t serial,
 	}
 }
 
+static void
+debug_binding_cancel(struct weston_keyboard_grab *grab)
+{
+	struct debug_binding_grab *db = (struct debug_binding_grab *) grab;
+
+	weston_keyboard_end_grab(grab->keyboard);
+	free(db);
+}
+
 struct weston_keyboard_grab_interface debug_binding_keyboard_grab = {
 	debug_binding_key,
-	debug_binding_modifiers
+	debug_binding_modifiers,
+	debug_binding_cancel,
 };
 
 static void

src/text-backend.c

@@ -570,9 +570,16 @@ input_method_context_grab_modifier(struct weston_keyboard_grab *grab, uint32_t s
 				   mods_locked, group);
 }
 
+static void
+input_method_context_grab_cancel(struct weston_keyboard_grab *grab)
+{
+	weston_keyboard_end_grab(grab->keyboard);
+}
+
 static const struct weston_keyboard_grab_interface input_method_context_grab = {
 	input_method_context_grab_key,
 	input_method_context_grab_modifier,
+	input_method_context_grab_cancel,
 };
 
 static void