Add an option to control the audio bell volume on X11

CHANGELOG.rst

@@ -34,6 +34,8 @@ version 0.5.1 [2017-12-01]
 
 - Drop the dependency on glfw (kitty now uses a modified, bundled copy of glfw)
 
+- Add an option to control the audio bell volume on X11 systems
+
 
 version 0.5.0 [2017-11-19]
 ---------------------------

kitty/cocoa_window.m

@@ -152,6 +152,10 @@
     return true;
 }
 
+void
+cocoa_audio_bell(void) {
+    NSBeep();
+}
  
 PyObject*
 cocoa_get_lang(PyObject UNUSED *self) {

kitty/config.py

@@ -257,6 +257,7 @@ def box_drawing_scale(x):
     'macos_hide_titlebar': to_bool,
     'macos_option_as_alt': to_bool,
     'box_drawing_scale': box_drawing_scale,
+    'x11_bell_volume': int,
 }
 
 for name in (

kitty/data-types.h

@@ -272,4 +272,4 @@ void scroll_event(double, double);
 void set_special_key_combo(int glfw_key, int mods);
 void on_text_input(unsigned int codepoint, int mods);
 void on_key_input(int key, int scancode, int action, int mods);
-void request_window_attention(id_type);
+void request_window_attention(id_type, bool);

kitty/glfw.c

@@ -6,9 +6,11 @@
 
 #include "state.h"
 #include <structmember.h>
+#include <dlfcn.h>
 #include "glfw-wrapper.h"
 extern bool cocoa_make_window_resizable(void *w);
 extern void cocoa_create_global_menu(void);
+extern void cocoa_audio_bell(void);
 
 #if GLFW_KEY_LAST >= MAX_KEY_COUNT
 #error "glfw has too many keys, you should increase MAX_KEY_COUNT"
@@ -31,6 +33,23 @@ update_os_window_viewport(OSWindow *window, bool notify_boss) {
     window->last_resize_at = monotonic();
 }
 
+static void*
+load_libX11(bool unload) {
+    static void* ans = NULL;
+    static bool tried = false;
+    if (unload) { if (ans) { dlclose(ans); ans = NULL; }; return NULL; }
+    if (!tried) {
+        tried = true;
+        ans = dlopen("libX11.so", RTLD_LAZY);
+        if (ans == NULL) fprintf(stderr, "Failed to load libX11.so with error: %s\n", dlerror());
+    }
+    return ans;
+}
+
+typedef bool (*xkb_bell_func)(void*, int32_t, int, void*);
+xkb_bell_func xkb_bell = NULL;
+
+
 
 // callbacks {{{
 
@@ -327,6 +346,7 @@ glfw_init(PyObject UNUSED *self, PyObject *args) {
 PyObject*
 glfw_terminate(PyObject UNUSED *self) {
     glfwTerminate();
+    load_libX11(true);
     Py_RETURN_NONE;
 }
 
@@ -477,10 +497,38 @@ toggle_fullscreen(PyObject UNUSED *self) {
     }
 }
 
+void 
+ring_audio_bell(OSWindow *w) {
+#ifdef __APPLE__
+    (void)w;
+    cocoa_audio_bell();
+#else
+    if (glfwGetX11Display) {
+        static bool tried = false;
+        if (!tried) {
+            tried = true;
+            void *lib = load_libX11(false);
+            if (lib) {
+                *(void **) (&xkb_bell) = dlsym(lib, "XkbBell");
+                if (!xkb_bell) fprintf(stderr, "Failed to load the XkbBell function with error: %s\n", dlerror());
+            }
+        }
+        if (xkb_bell) {
+            void* display = glfwGetX11Display();
+            int32_t x11win = glfwGetX11Window(w->handle);
+            if (display) {
+                xkb_bell(display, x11win, OPT(x11_bell_volume), NULL);
+            }
+        }
+    }
+#endif
+}
+
 void
-request_window_attention(id_type kitty_window_id) {
+request_window_attention(id_type kitty_window_id, bool audio_bell) {
     OSWindow *w = os_window_for_kitty_window(kitty_window_id);
     if (w) {
+        if (audio_bell) ring_audio_bell(w);
         glfwRequestWindowAttention(w->handle);
         glfwPostEmptyEvent();
     }

kitty/kitty.conf

@@ -331,3 +331,7 @@ macos_hide_titlebar no
 # break any Alt+key keyboard shortcuts in your terminal programs, but you
 # can use the macOS unicode input technique.
 macos_option_as_alt yes
+
+# The number is a percentage of maximum volume.
+# See man XBell for details.
+x11_bell_volume 80

kitty/screen.c

@@ -1009,22 +1009,7 @@ screen_invert_colors(Screen *self) {
 
 void 
 screen_bell(Screen *self) {  
-    if (global_state.opts.enable_audio_bell) {
-        int fd = open("/dev/tty", O_WRONLY | O_CLOEXEC | O_NOCTTY);
-        if (fd > 0) {
-            static const char bell[2] = {7, 0};
-            while(true) {
-                if (write(fd, &bell, sizeof(bell)) == sizeof(bell)) break;
-                if (errno == EINTR) continue;
-                break;
-            }
-            close(fd);
-        }
-    }
-    if (global_state.opts.visual_bell_duration > 0) {
-        self->start_visual_bell_at = monotonic();
-    }
-    request_window_attention(self->window_id);
+    request_window_attention(self->window_id, OPT(enable_audio_bell));
 } 
 
 void 

kitty/state.c

@@ -308,6 +308,7 @@ PYWRAP1(set_options) {
     S(cursor_blink_interval, PyFloat_AsDouble);
     S(cursor_stop_blinking_after, PyFloat_AsDouble);
     S(cursor_shape, PyLong_AsLong);
+    S(x11_bell_volume, PyLong_AsLong);
     S(mouse_hide_wait, PyFloat_AsDouble);
     S(wheel_scroll_multiplier, PyFloat_AsDouble);
     S(open_url_modifiers, PyLong_AsUnsignedLong);

kitty/state.h

@@ -21,6 +21,7 @@ typedef struct {
     bool focus_follows_mouse;
     bool macos_option_as_alt, macos_hide_titlebar;
     int adjust_line_height_px;
+    int x11_bell_volume;
     float adjust_line_height_frac;
 } Options;