1 files changed, 147 insertions, 0 deletions
diff --git a/mod/keycallback.c b/mod/keycallback.c
new file mode 100644
index 0000000..2352cbf
--- /dev/null
+++ b/mod/keycallback.c
@@ -0,0 +1,147 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "melisma/ring.h"
+
+static int fn = LUA_NOREF;
+static struct termios tty = {0};
+static struct termios oldtty = {0};
+static lua_State *state;
+static ml_ring *ring = NULL;
+
+static void make_arg(lua_State *s, size_t len, const void *data)
+{
+	lua_pushlstring(s,data,len);
+}
+
+static void io_handler(int fd, int flags, void *args)
+{
+	char c;
+
+	if (read(fd,&c,sizeof c) <= 0)
+	{
+		return;
+	}
+
+	ml_ring_put_blocking(ring,*(uint8_t*) &c);
+}
+
+static void cleanup(void)
+{
+	tcsetattr(STDIN_FILENO,TCSANOW,&oldtty);
+}
+
+static void proc(const ml_proc_args *args)
+{
+	if (fn == LUA_NOREF)
+	{
+		return;
+	}
+
+	char buf[1];
+	while (ml_ring_read(ring,buf,sizeof buf) == sizeof buf)
+	{
+		lua_pushlstring(state,buf,sizeof buf);
+		int arg = luaL_ref(state,LUA_REGISTRYINDEX);
+		ml_schedule_event(0,fn,arg);
+	}
+}
+
+static void setup(lua_State *s)
+{
+	static bool init = false;
+
+	if (init)
+	{
+		return;
+	}
+
+	init = true;
+
+	tcgetattr(STDIN_FILENO,&oldtty);
+	tty = oldtty;
+	tty.c_lflag &= ~ECHO;
+	tty.c_lflag &= ~ICANON;
+	tcsetattr(STDIN_FILENO,TCSANOW,&tty);
+	tcflush(STDIN_FILENO,TCIFLUSH);
+
+	ml_add_io_handler(STDIN_FILENO,POLLIN,io_handler,NULL);
+	ring = ml_ring_init(4096);
+	state = s;
+
+	ml_node *node = ml_create_node(proc,NULL);
+	ml_channel *src = ml_add_output(node);
+	ml_channel *dst = ml_add_input(ml_get_root_node());
+	ml_connect(src,dst);
+	ml_label_node(node,"keycallback");
+
+	atexit(cleanup);
+}
+
+static int l_set(lua_State *s)
+{
+	if (fn != LUA_NOREF)
+	{
+		luaL_unref(s,LUA_REGISTRYINDEX,fn);
+		fn = LUA_NOREF;
+	}
+
+	if (lua_isnil(s,1))
+	{
+		return 0;
+	}
+
+	luaL_checktype(s,1,LUA_TFUNCTION);
+	lua_pushvalue(s,1);
+	fn = luaL_ref(s,LUA_REGISTRYINDEX);
+
+	setup(s);
+
+	return 0;
+}
+
+int luaopen_melisma_keycallback(lua_State *s)
+{
+/*** Set callback for keyboard input.
+	local mkeycallback = require 'melisma.keycallback'
+
+	mkeycallback.set(function(c)
+		print('you pressed', c)
+	end)
+@module keycallback
+*/
+	lua_newtable(s);
+	int tbl = lua_absindex(s,lua_gettop(s));
+
+/*** Set the callback.
+@function set
+@tparam function fn Callback function.
+*/
+	lua_pushcfunction(s,l_set);
+	lua_setfield(s,tbl,"set");
+
+	lua_settop(s,tbl);
+	return 1;
+}