Added XCB initialization

src/kiwmi/xcb.c

@@ -0,0 +1,55 @@
+/* Copyright (c), Niclas Meyer <niclas@countingsort.com>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include "xcb.h"
+
+#include <xcb/xcb.h>
+
+#include "common.h"
+
+#define ROOT_MASK ( XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY | XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT )
+
+int g_dpy_fd;
+xcb_connection_t *g_dpy;
+
+static xcb_screen_t *g_screen;
+static xcb_window_t g_root;
+
+void
+init_xcb(void)
+{
+	uint32_t values[] = { ROOT_MASK };
+	xcb_generic_error_t *err;
+
+	g_dpy = xcb_connect(NULL, NULL);
+
+	if (xcb_connection_has_error(g_dpy)) {
+		die("failed to open XCB connection\n");
+	}
+
+	if (!(g_screen = xcb_setup_roots_iterator(xcb_get_setup(g_dpy)).data)) {
+		die("failed to open default display\n");
+	}
+
+	g_root = g_screen->root;
+
+	err = xcb_request_check(
+		g_dpy,
+		xcb_change_window_attributes_checked(
+			g_dpy,
+			g_root,
+			XCB_CW_EVENT_MASK,
+			values
+		)
+	);
+
+	if (err) {
+		die("another window manager is already running\n");
+	}
+
+	g_dpy_fd = xcb_get_file_descriptor(g_dpy);
+}

src/kiwmi/xcb.h

@@ -0,0 +1,18 @@
+/* Copyright (c), Niclas Meyer <niclas@countingsort.com>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef XCB_H
+#define XCB_H
+
+#include <xcb/xcb.h>
+
+void init_xcb(void);
+
+extern int g_dpy_fd;
+extern xcb_connection_t *g_dpy;
+
+#endif /* XCB_H */