2 * vim:ts=4:sw=4:expandtab
4 * i3 - an improved dynamic tiling window manager
5 * © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
16 #include <xcb/xcb_aux.h>
21 * Try to get the contents of the given atom (for example I3_SOCKET_PATH) from
22 * the X11 root window and return NULL if it doesn’t work.
24 * If the provided XCB connection is NULL, a new connection will be
27 * The memory for the contents is dynamically allocated and has to be
28 * free()d by the caller.
31 char *root_atom_contents(const char *atomname, xcb_connection_t *provided_conn, int screen) {
32 xcb_intern_atom_cookie_t atom_cookie;
33 xcb_intern_atom_reply_t *atom_reply;
35 size_t content_max_words = 256;
36 xcb_connection_t *conn = provided_conn;
38 if (provided_conn == NULL &&
39 ((conn = xcb_connect(NULL, &screen)) == NULL ||
40 xcb_connection_has_error(conn)))
43 atom_cookie = xcb_intern_atom(conn, 0, strlen(atomname), atomname);
45 xcb_screen_t *root_screen = xcb_aux_get_screen(conn, screen);
46 xcb_window_t root = root_screen->root;
48 atom_reply = xcb_intern_atom_reply(conn, atom_cookie, NULL);
49 if (atom_reply == NULL)
52 xcb_get_property_cookie_t prop_cookie;
53 xcb_get_property_reply_t *prop_reply;
54 prop_cookie = xcb_get_property_unchecked(conn, false, root, atom_reply->atom,
55 XCB_GET_PROPERTY_TYPE_ANY, 0, content_max_words);
56 prop_reply = xcb_get_property_reply(conn, prop_cookie, NULL);
57 if (prop_reply == NULL) {
61 if (xcb_get_property_value_length(prop_reply) > 0 && prop_reply->bytes_after > 0) {
62 /* We received an incomplete value. Ask again but with a properly
64 content_max_words += ceil(prop_reply->bytes_after / 4.0);
65 /* Repeat the request, with adjusted size */
67 prop_cookie = xcb_get_property_unchecked(conn, false, root, atom_reply->atom,
68 XCB_GET_PROPERTY_TYPE_ANY, 0, content_max_words);
69 prop_reply = xcb_get_property_reply(conn, prop_cookie, NULL);
70 if (prop_reply == NULL) {
75 if (xcb_get_property_value_length(prop_reply) == 0) {
80 if (prop_reply->type == XCB_ATOM_CARDINAL) {
81 /* We treat a CARDINAL as a >= 32-bit unsigned int. The only CARDINAL
82 * we query is I3_PID, which is 32-bit. */
83 if (asprintf(&content, "%u", *((unsigned int*)xcb_get_property_value(prop_reply))) == -1) {
89 if (asprintf(&content, "%.*s", xcb_get_property_value_length(prop_reply),
90 (char*)xcb_get_property_value(prop_reply)) == -1) {
96 if (provided_conn == NULL)