xserver: introduce isolated core xserver api

In preparation for monitoring overlays being shared across vwm and vmon,
adding a common xserver abstraction for both to use and overlay to depend
on.

1 files changed, 67 insertions, 0 deletions

diff --git a/src/xserver.c b/src/xserver.c
new file mode 100644
index 0000000..114a924
--- /dev/null
+++ b/src/xserver.c
@@ -0,0 +1,67 @@
+#include <X11/Xlib.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "util.h"
+#include "xserver.h"
+
+/* xserver context shared by vwm and vmon.
+ * This is the X part monitor.c interfaces with, so monitor.c can avoid depending
+ * on vwm_t which won't exist in the vmon tool.
+ */
+
+static int errhandler(Display *display, XErrorEvent *err)
+{
+	/* TODO */
+	return 1;
+}
+
+/* open the X display server, initializing *xserver on success. */
+vwm_xserver_t * vwm_xserver_open(void)
+{
+	vwm_xserver_t	*xserver;
+
+	if (!(xserver = calloc(sizeof(vwm_xserver_t), 1))) {
+		VWM_ERROR("Cannot allocate vwm_xserver_t");
+		goto _err;
+	}
+
+	if (!(xserver->display = XOpenDisplay(NULL))) {
+		VWM_ERROR("Cannot open display");
+		goto _err_free;
+	}
+
+	/* prevent children from inheriting the X connection */
+	if (fcntl(ConnectionNumber(xserver->display), F_SETFD, FD_CLOEXEC) < 0) {
+		VWM_ERROR("Cannot set FD_CLOEXEC on X connection");
+		goto _err_xclose;
+	}
+
+	XSetErrorHandler(errhandler); /* TODO, this may not belong here. */
+
+	xserver->screen_num = DefaultScreen(xserver->display);
+	xserver->gc = XCreateGC(xserver->display, XSERVER_XROOT(xserver), 0, NULL);
+	xserver->cmap = DefaultColormap(xserver->display, xserver->screen_num);
+
+	return xserver;
+
+
+_err_xclose:
+	XCloseDisplay(xserver->display);
+
+_err_free:
+	free(xserver);
+
+_err:
+	return NULL;
+}
+
+
+/* close on opened xserver */
+void vwm_xserver_close(vwm_xserver_t *xserver)
+{
+	XFlush(xserver->display);
+	XCloseDisplay(xserver->display);
+	free(xserver);
+}