Linux: Use the system "bell" for the terminal bell

Adds libcanberra as a new dependency to play the system sound.

docs/build.rst

@@ -20,6 +20,7 @@ Run-time dependencies:
     * libpng
     * freetype (not needed on macOS)
     * fontconfig (not needed on macOS)
+    * libcanberra (not needed on macOS)
     * ImageMagick (optional, needed to use the ``kitty icat`` tool to display images in the terminal)
     * pygments (optional, need for syntax highlighting in ``kitty +kitten diff``)
 
@@ -28,7 +29,7 @@ Build-time dependencies:
     * gcc or clang
     * pkg-config
     * For building on Linux in addition to the above dependencies you might also need to install the ``-dev`` packages for:
-      ``libdbus-1-dev``, ``libxcursor-dev``, ``libxrandr-dev``, ``libxi-dev``, ``libxinerama-dev``, ``libgl1-mesa-dev``, ``libxkbcommon-x11-dev``, ``libfontconfig-dev`` and ``libpython-dev``.
+      ``libdbus-1-dev``, ``libxcursor-dev``, ``libxrandr-dev``, ``libxi-dev``, ``libxinerama-dev``, ``libgl1-mesa-dev``, ``libxkbcommon-x11-dev``, ``libfontconfig-dev``, ``libcanberra-dev`` and ``libpython-dev``.
       if they are not already installed by your distro.
 
 Install and run from source

docs/changelog.rst

@@ -38,6 +38,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Fix an out of bounds read causing a crash when selecting text with the mouse
   in the alternate screen mode (:iss:`1578`)
 
+- Linux: Use the system "bell" sound for the terminal bell. Adds libcanberra
+  as a new dependency to play the system sound.
+
 
 0.14.2 [2019-06-09]
 ---------------------

kitty/data-types.h

@@ -307,5 +307,8 @@ void fake_scroll(int, bool);
 void set_special_key_combo(int glfw_key, int mods, bool is_native);
 void on_key_input(int key, int scancode, int action, int mods, const char*, int);
 void request_window_attention(id_type, bool);
+#ifndef __APPLE__
+void play_canberra_sound(const char *which_sound, const char *event_id);
+#endif
 SPRITE_MAP_HANDLE alloc_sprite_map(unsigned int, unsigned int);
 SPRITE_MAP_HANDLE free_sprite_map(SPRITE_MAP_HANDLE);

kitty/desktop.c

@@ -7,6 +7,7 @@
 
 #include "data-types.h"
 #include <dlfcn.h>
+#include <canberra.h>
 
 #define FUNC(name, restype, ...) typedef restype (*name##_func)(__VA_ARGS__); static name##_func name = NULL
 #define LOAD_FUNC(handle, name) {\
@@ -89,9 +90,25 @@ static PyMethodDef module_methods[] = {
     {NULL, NULL, 0, NULL}        /* Sentinel */
 };
 
+static ca_context *canberra_ctx = NULL;
+
+void
+play_canberra_sound(const char *which_sound, const char *event_id) {
+    if (canberra_ctx == NULL) ca_context_create(&canberra_ctx);
+    ca_context_play(
+        canberra_ctx, 0,
+        CA_PROP_EVENT_ID, which_sound,
+		CA_PROP_EVENT_DESCRIPTION, event_id,
+		NULL
+    );
+}
+
 static void
 finalize(void) {
     if (libsn_handle) dlclose(libsn_handle);
+    libsn_handle = NULL;
+    if (canberra_ctx) ca_context_destroy(canberra_ctx);
+    canberra_ctx = NULL;
 }
 
 bool

kitty/glfw.c

@@ -819,14 +819,18 @@ get_clipboard_string(PYNOARG) {
 }
 
 void
-ring_audio_bell(OSWindow *w) {
+ring_audio_bell(OSWindow *w UNUSED) {
     static double last_bell_at = -1;
     double now = monotonic();
     if (now - last_bell_at <= 0.1) return;
     last_bell_at = now;
+#ifdef __APPLE__
     if (w->handle) {
         glfwWindowBell(w->handle);
     }
+#else
+    play_canberra_sound("bell", "kitty bell");
+#endif
 }
 
 static PyObject*

setup.py

@@ -273,6 +273,9 @@ def kitty_env():
     gl_libs = ['-framework', 'OpenGL'] if is_macos else pkg_config('gl', '--libs')
     libpng = pkg_config('libpng', '--libs')
     ans.ldpaths += pylib + font_libs + gl_libs + libpng
+    if not is_macos:
+        cflags.extend(pkg_config('libcanberra', '--cflags-only-I'))
+        ans.ldpaths += pkg_config('libcanberra', '--libs')
     if is_macos:
         ans.ldpaths.extend('-framework Cocoa'.split())
     else: