From 0f19b6ed57719fd07845d57b08fa8f92b77352ac Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20=C5=A0ediv=C3=BD?= <sedivy.miro@gmail.com>
Date: Sun, 10 Jan 2021 15:55:29 +0100
Subject: [PATCH] add xevent c bindings.

---
 internal/desktop/xevent/xevent.c  | 45 +++++++++++++++++++++++++
 internal/desktop/xevent/xevent.go | 55 +++++++++++++++++++++++++++++++
 internal/desktop/xevent/xevent.h  | 15 +++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 internal/desktop/xevent/xevent.c
 create mode 100644 internal/desktop/xevent/xevent.go
 create mode 100644 internal/desktop/xevent/xevent.h

diff --git a/internal/desktop/xevent/xevent.c b/internal/desktop/xevent/xevent.c
new file mode 100644
index 00000000..d7dfe5f1
--- /dev/null
+++ b/internal/desktop/xevent/xevent.c
@@ -0,0 +1,45 @@
+#include "xevent.h"
+
+static int XEventError(Display *display, XErrorEvent *event) {
+  char message[100];
+
+  int error;
+  error = XGetErrorText(display, event->error_code, message, sizeof(message));
+  if (error) {
+    goXEventError(event, "Could not get error message.");
+  } else {
+    goXEventError(event, message);
+  }
+
+  return 1;
+}
+
+void XEventLoop(char *name) {
+  Display *display = XOpenDisplay(name);
+  Window root = RootWindow(display, 0);
+
+  int xfixes_event_base, xfixes_error_base;
+  if (!XFixesQueryExtension(display, &xfixes_event_base, &xfixes_error_base)) {
+    return;
+  }
+
+  XFixesSelectCursorInput(display, root, XFixesDisplayCursorNotifyMask);
+  XSync(display, 0);
+  XSetErrorHandler(XEventError);
+
+  while (goXEventActive()) {
+    XEvent event;
+    XNextEvent(display, &event);
+
+    // XFixesDisplayCursorNotify
+    if (event.type == xfixes_event_base + 1) {
+      XFixesCursorNotifyEvent notifyEvent = *((XFixesCursorNotifyEvent *) &event);
+      if (notifyEvent.subtype == XFixesDisplayCursorNotify) {
+        goXEventCursorChanged(notifyEvent);
+        continue;
+      }
+    }
+  }
+
+  XCloseDisplay(display);
+}
diff --git a/internal/desktop/xevent/xevent.go b/internal/desktop/xevent/xevent.go
new file mode 100644
index 00000000..6a6fb4c0
--- /dev/null
+++ b/internal/desktop/xevent/xevent.go
@@ -0,0 +1,55 @@
+package xevent
+
+/*
+#cgo linux CFLAGS: -I/usr/src -I/usr/local/include/
+#cgo linux LDFLAGS: -L/usr/src -L/usr/local/lib -lX11 -lxcb -lXfixes
+
+#include "xevent.h"
+*/
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/kataras/go-events"
+)
+
+var emmiter events.EventEmmiter
+
+func init() {
+	emmiter = events.New()
+}
+
+func EventLoop(display string) {
+	displayUnsafe := C.CString(display)
+	defer C.free(unsafe.Pointer(displayUnsafe))
+
+	C.XEventLoop(displayUnsafe)
+}
+
+func OnCursorChanged(listener func(serial uint64)) {
+	emmiter.On("cursor-changed", func(payload ...interface{}) {
+		listener(payload[0].(uint64))
+	})
+}
+
+func OnEventError(listener func(error_code uint8, message string, request_code uint8, minor_code uint8)) {
+	emmiter.On("event-error", func(payload ...interface{}) {
+		listener(payload[0].(uint8), payload[1].(string), payload[2].(uint8), payload[3].(uint8))
+	})
+}
+
+//export goXEventCursorChanged
+func goXEventCursorChanged(event C.XFixesCursorNotifyEvent) {
+	emmiter.Emit("cursor-changed", uint64(event.cursor_serial))
+}
+
+//export goXEventError
+func goXEventError(event *C.XErrorEvent, message *C.char) {
+	emmiter.Emit("event-error", uint8(event.error_code), C.GoString(message), uint8(event.request_code), uint8(event.minor_code))
+}
+
+//export goXEventActive
+func goXEventActive() C.int {
+	return C.int(1)
+}
diff --git a/internal/desktop/xevent/xevent.h b/internal/desktop/xevent/xevent.h
new file mode 100644
index 00000000..24949f45
--- /dev/null
+++ b/internal/desktop/xevent/xevent.h
@@ -0,0 +1,15 @@
+#pragma once
+
+#include <X11/Xlib.h>
+#include <X11/extensions/Xfixes.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+extern void goXEventCursorChanged(XFixesCursorNotifyEvent event);
+extern void goXEventError(XErrorEvent *event, char *message);
+extern int goXEventActive();
+
+static int XEventError(Display *display, XErrorEvent *event);
+void XEventLoop(char *display);
+