Add support for the bell "\a" character

Closes #39

README.md

@@ -158,6 +158,10 @@ There are three example scenes included in this project which you can study to l
 - terminal.tscn
 - asciicast.tscn
 
+## Credits
+
+[bell.wav](/examples/bell.wav) by InspectorJ (<www.jshaw.co.uk>), downloaded from [freesound.org](https://freesound.org/people/InspectorJ/sounds/484344/), released under [CC-BY-3.0](https://creativecommons.org/licenses/by/3.0/).
+
 ## License
 
 If you contribute code to this project, you are implicitly allowing your code to be distributed under the MIT license.

addons/godot_xterm/native/src/terminal.cpp

@@ -268,6 +268,11 @@ static int text_draw_cb(struct tsm_screen *con, uint64_t id, const uint32_t *ch,
   return 0;
 }
 
+static void bell_cb(tsm_vte *_vte, void *data) {
+  Terminal *terminal = static_cast<Terminal *>(data);
+  terminal->emit_signal("bell");
+}
+
 void Terminal::_register_methods() {
   register_method("_init", &Terminal::_init);
   register_method("_ready", &Terminal::_ready);
@@ -291,6 +296,7 @@ void Terminal::_register_methods() {
                             "event", GODOT_VARIANT_TYPE_OBJECT);
   register_signal<Terminal>("size_changed", "new_size",
                             GODOT_VARIANT_TYPE_VECTOR2);
+  register_signal<Terminal>("bell", Dictionary());
 }
 
 Terminal::Terminal() {}
@@ -310,6 +316,8 @@ void Terminal::_init() {
   if (tsm_vte_new(&vte, screen, write_cb, this, NULL, NULL)) {
     ERR_PRINT("Error creating new tsm vte");
   }
+
+  tsm_vte_set_bell_cb(vte, bell_cb, this);
 }
 
 void Terminal::_ready() { update_theme(); }

addons/godot_xterm/nodes/terminal/terminal.gd

@@ -6,6 +6,7 @@ const DefaultTheme = preload("../../themes/default.tres")
 signal data_sent(data)
 signal key_pressed(data, event)
 signal size_changed(new_size)
+signal bell
 
 enum UpdateMode {
 	DISABLED,
@@ -62,6 +63,7 @@ func _ready():
 	_native_terminal.connect("data_sent", self, "_on_data_sent")
 	_native_terminal.connect("key_pressed", self, "_on_key_pressed")
 	_native_terminal.connect("size_changed", self, "_on_size_changed")
+	_native_terminal.connect("bell", self, "_on_bell")
 
 	_viewport.size = rect_size
 	_viewport.render_target_update_mode = Viewport.UPDATE_ALWAYS
@@ -112,6 +114,10 @@ func _on_size_changed(new_size: Vector2):
 	emit_signal("size_changed", new_size)
 
 
+func _on_bell():
+	emit_signal("bell")
+
+
 func _set_size_warning(value):
 	if value:
 		push_warning(

examples/bell.wav.import

@@ -0,0 +1,21 @@
+[remap]
+
+importer="wav"
+type="AudioStreamSample"
+path="res://.import/bell.wav-90c86fbe33880ba47c154bebbc865497.sample"
+
+[deps]
+
+source_file="res://examples/bell.wav"
+dest_files=[ "res://.import/bell.wav-90c86fbe33880ba47c154bebbc865497.sample" ]
+
+[params]
+
+force/8_bit=false
+force/mono=false
+force/max_rate=false
+force/max_rate_hz=44100
+edit/trim=false
+edit/normalize=false
+edit/loop=false
+compress/mode=0

examples/terminal/terminal.gd

@@ -2,6 +2,31 @@ extends GDXterm.Terminal
 
 onready var pty = $PTY
 
+var _next_bell := true
+
 
 func _ready():
 	pty.fork(OS.get_environment("SHELL"))
+
+
+func _on_Terminal_bell():
+	# Limit the rate at which bells can be rung in case the user does something crazy such as
+	# `while true; do echo -e "\a"; done`
+	# which causes a real mess if we keep adding AudioStreamPlayers.
+	if not _next_bell:
+		return
+
+	var player := AudioStreamPlayer.new()
+	player.stream = preload("../bell.wav")
+	player.autoplay = true
+	player.connect("finished", self, "_on_player_finished", [player])
+	add_child(player)
+	_next_bell = false
+
+
+func _on_player_finished(player: AudioStreamPlayer):
+	player.queue_free()
+
+
+func _on_Timer_timeout():
+	_next_bell = true

examples/terminal/terminal.tscn

@@ -19,3 +19,10 @@ env = {
 "COLORTERM": "truecolor",
 "TERM": "xterm-256color"
 }
+
+[node name="Timer" type="Timer" parent="."]
+wait_time = 0.1
+autostart = true
+
+[connection signal="bell" from="." to="." method="_on_Terminal_bell"]
+[connection signal="timeout" from="Timer" to="." method="_on_Timer_timeout"]

test/unit/terminal.test.gd

@@ -0,0 +1,27 @@
+extends WAT.Test
+
+var term: GDXterm.Terminal
+
+
+func pre():
+	term = GDXterm.Terminal.new()
+	term.rect_size = Vector2(400, 200)
+	add_child(term)
+
+
+func post():
+	term.free()
+
+
+func after():
+	term.free()
+
+
+func test_bell() -> void:
+	term.write(char(7))
+	term.write(char(0x07))
+	term.write("\a")
+	term.write("\u0007")
+	term.write("'Ask not for whom the \a tolls; it tolls for thee' - John Donne")
+	yield(until_signal(term, "bell", 1), YIELD)
+	asserts.signal_was_emitted_x_times(term, "bell", 5)