From 6060db32b949d62757b668f972648465f1e302c7 Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom@tomsmeding.com>
Date: Wed, 31 Jan 2024 15:42:17 +0100
Subject: Initial

---
 xutil.cpp | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 xutil.cpp

(limited to 'xutil.cpp')

diff --git a/xutil.cpp b/xutil.cpp
new file mode 100644
index 0000000..7adceaa
--- /dev/null
+++ b/xutil.cpp
@@ -0,0 +1,85 @@
+#include <iostream>
+#include <functional>
+#include <X11/XKBlib.h>
+#include "xutil.h"
+
+
+namespace x {
+
+	Keycode Keysym::toCode(Display *dpy) const {
+		return XKeysymToKeycode(dpy, sym);
+	}
+
+	void bel(Display *dpy) {
+		XkbBell(dpy, None, 100, None);
+	}
+
+	using UponExitF = UponExit<std::function<void()>>;
+
+	UponExitF XGrabKeyRAII(Display *dpy, Keycode code, int modifier, Window win) {
+		XGrabKey(dpy, (unsigned int)code, modifier, win, False, GrabModeAsync, GrabModeAsync);
+		return UponExitF{[dpy, code, modifier, win]() {
+			XUngrabKey(dpy, (unsigned int)code, modifier, win);
+			XSync(dpy, False);
+		}};
+	}
+
+	UponExitF XGrabKeyboardRAII(Display *dpy, Window win) {
+		int ret = XGrabKeyboard(dpy, win, False, GrabModeAsync, GrabModeAsync, CurrentTime);
+		if (ret == AlreadyGrabbed) {
+			XUngrabKeyboard(dpy, CurrentTime);
+			XSync(dpy, False);
+			throw std::runtime_error("Cannot grab keyboard: already grabbed");
+		}
+		return UponExitF{[dpy]() {
+			XUngrabKeyboard(dpy, CurrentTime);
+			XSync(dpy, False);
+		}};
+	}
+
+	std::pair<Display*, UponExitF> XOpenDisplayRAII(const char *name) {
+		Display *dpy = XOpenDisplay(name);
+		if (dpy == nullptr) {
+			std::cerr << "Cannot open X display" << std::endl;
+			exit(1);
+		}
+		return std::make_pair(dpy, UponExitF{[dpy]() {
+			XCloseDisplay(dpy);
+		}});
+	}
+
+	void globalKeyWatch(Display *dpy, Keysym keysym, std::function<bool(const XKeyEvent&)> callback) {
+		const Window root = DefaultRootWindow(dpy);
+		const Keycode keycode = keysym.toCode(dpy);
+
+		auto guard = XGrabKeyRAII(dpy, keycode, AnyModifier, root);
+
+		XSelectInput(dpy, root, KeyPressMask);
+		while (true) {
+			XEvent ev;
+			XNextEvent(dpy, &ev);
+			if (ev.type == KeyPress && ev.xkey.keycode == (unsigned int)keycode) {
+				if (callback(ev.xkey)) return;
+			}
+		}
+	}
+
+	void globalKeyboardGrab(Display *dpy, std::function<bool(const XKeyEvent&)> callback) {
+		const Window root = DefaultRootWindow(dpy);
+
+		try {
+			auto guard = XGrabKeyboardRAII(dpy, root);
+
+			while (true) {
+				XEvent ev;
+				XNextEvent(dpy, &ev);
+				if (ev.type == KeyPress) {
+					if (callback(ev.xkey)) return;
+				}
+			}
+		} catch (std::exception &e) {
+			std::cerr << e.what() << std::endl;
+		}
+	}
+
+}
-- 
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