From 5e58d46cc1a90810e3ee76203cee8ca2f14fb462 Mon Sep 17 00:00:00 2001 From: emersion Date: Mon, 12 Feb 2018 09:12:31 +0100 Subject: Add wlr_signal_emit_safe --- util/meson.build | 1 + util/signal.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+) create mode 100644 util/signal.c (limited to 'util') diff --git a/util/meson.build b/util/meson.build index 34aa428b..adc52a53 100644 --- a/util/meson.build +++ b/util/meson.build @@ -4,6 +4,7 @@ lib_wlr_util = static_library( 'log.c', 'os-compatibility.c', 'region.c', + 'signal.c', ), include_directories: wlr_inc, dependencies: [wayland_server, pixman], diff --git a/util/signal.c b/util/signal.c new file mode 100644 index 00000000..91c4f571 --- /dev/null +++ b/util/signal.c @@ -0,0 +1,34 @@ +#include + +static void handle_noop(struct wl_listener *listener, void *data) { + // Do nothing +} + +void wlr_signal_emit_safe(struct wl_signal *signal, void *data) { + struct wl_listener cursor; + struct wl_listener end; + + /* Add two special markers: one cursor and one end marker. This way, we know + * that we've already called listeners on the left of the cursor and that we + * don't want to call listeners on the right of the end marker. The 'it' + * function can remove any element it wants from the list without troubles. + * wl_list_for_each_safe tries to be safe but it fails: it works fine + * if the current item is removed, but not if the next one is. */ + wl_list_insert(&signal->listener_list, &cursor.link); + cursor.notify = handle_noop; + wl_list_insert(signal->listener_list.prev, &end.link); + end.notify = handle_noop; + + while (cursor.link.next != &end.link) { + struct wl_list *pos = cursor.link.next; + struct wl_listener *l = wl_container_of(pos, l, link); + + wl_list_remove(&cursor.link); + wl_list_insert(pos, &cursor.link); + + l->notify(l, data); + } + + wl_list_remove(&cursor.link); + wl_list_remove(&end.link); +} -- cgit v1.2.3