Add rudimentary terminal to editor's bottom panel

In order to use the gdnative library as an editor plugin it was
neccessary to set the `reloadable` property of the gdnlib file to false,
in order to prevent crashes when the godot editor window lost focus.

This may have consequences when recompiling the library.
See: https://docs.godotengine.org/en/3.3/classes/class_gdnativelibrary.html#class-gdnativelibrary-property-reloadable

Still crashes quite frequently and doesn't close child processes
properly.

Part of #43.

addons/godot_xterm/editor_plugins/terminal/editor_terminal.gd

@@ -0,0 +1,78 @@
+tool
+extends "res://addons/godot_xterm/nodes/terminal/terminal.gd"
+
+var editor_settings: EditorSettings
+var timer := Timer.new()
+
+onready var pty = $PTY
+
+
+# Sets terminal colors according to a dictionary that maps terminal color names
+# to TextEditor theme color names.
+func _set_terminal_colors(color_map: Dictionary) -> void:
+	for key in color_map.keys():
+		var val: String = color_map[key]
+		var color: Color = editor_settings.get_setting("text_editor/highlighting/%s" % val)
+		theme.set_color(key, "Terminal", color)
+
+
+func _ready():
+	if not editor_settings:
+		return
+
+	theme = Theme.new()
+
+	# Use the same font as EditorLog.
+	theme.default_font = get_font("output_source", "EditorFonts")
+
+	# Get colors from TextEdit theme. Created using the default (Adaptive) theme
+	# for reference, but will probably cause strange results if using another theme
+	# better to use a dedicated terminal theme, rather than relying on this.
+	_set_terminal_colors(
+		{
+			"Black": "caret_background_color",
+			"Red": "keyword_color",
+			"Green": "gdscript/node_path_color",
+			"Yellow": "string_color",
+			"Blue": "function_color",
+			"Magenta": "symbol_color",
+			"Cyan": "gdscript/function_definition_color",
+			"Dark Grey": "comment_color",
+			"Light Grey": "text_color",
+			"Light Red": "breakpoint_color",
+			"Light Green": "base_type_color",
+			"Light Yellow": "search_result_color",
+			"Light Blue": "member_variable_color",
+			"Light Magenta": "code_folding_color",
+			"Light Cyan": "user_type_color",
+			"White": "text_selected_color",
+			"Background": "background_color",
+			"Foreground": "caret_color",
+		}
+	)
+	_native_terminal._update_theme()
+
+	# In editor _process is not called continuously unless the "Update Continuously"
+	# editor setting is enabled. This setting is disabled by default and uses 100%
+	# of one core when enabled, so best to leave it off and use a timer instead.
+	add_child(timer)
+	timer.wait_time = 0.025
+	timer.connect("timeout", self, "_poll")
+	timer.start()
+
+
+func _poll():
+	if pty and pty._pipe:
+		pty._pipe.poll()
+		update()
+
+
+func _input(event):
+	if not has_focus():
+		return
+
+	# We need to handle many input events otherwise keys such as TAB, ctrl, etc.
+	# will trigger editor shortcuts when using them in the terminal.
+	if event is InputEventKey:
+		get_tree().set_input_as_handled()
+		_gui_input(event)

addons/godot_xterm/editor_plugins/terminal/editor_terminal.tscn

@@ -0,0 +1,24 @@
+[gd_scene load_steps=3 format=2]
+
+[ext_resource path="res://addons/godot_xterm/editor_plugins/terminal/editor_terminal.gd" type="Script" id=1]
+[ext_resource path="res://addons/godot_xterm/nodes/pty/unix/pty_unix.gd" type="Script" id=2]
+
+[node name="Terminal" type="Control"]
+anchor_right = 1.0
+anchor_bottom = 1.0
+focus_mode = 1
+size_flags_horizontal = 4
+size_flags_vertical = 4
+script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+copy_on_selection = true
+
+[node name="PTY" type="Node" parent="."]
+script = ExtResource( 2 )
+terminal_path = NodePath("..")
+env = {
+"COLORTERM": "truecolor",
+"TERM": "xterm-256color"
+}

addons/godot_xterm/editor_plugins/terminal/terminal_panel.gd

@@ -0,0 +1,110 @@
+# Copyright (c) 2021, Leroy Hopson (MIT License).
+#
+# This file contains snippets of code derived from Godot's editor_node.cpp file.
+# These snippets are copyright of their authors and released under the MIT license:
+# - Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur (MIT License).
+# - Copyright (c) 2014-2021 Godot Engine contributors (MIT License).
+tool
+extends Control
+
+const EditorTerminal := preload("./editor_terminal.tscn")
+
+# Has access to the EditorSettings singleton so it can dynamically generate the
+# terminal color scheme based on editor theme settings.
+var editor_interface: EditorInterface
+
+onready var editor_settings: EditorSettings = editor_interface.get_editor_settings()
+onready var tabs: Tabs = $VBoxContainer/TabbarContainer/Tabs
+onready var tabbar_container: HBoxContainer = $VBoxContainer/TabbarContainer
+onready var add_button: ToolButton = $VBoxContainer/TabbarContainer/Tabs/AddButton
+onready var tab_container: TabContainer = $VBoxContainer/TabContainer
+onready var ready := true
+
+var _theme := Theme.new()
+var _tab_container_min_size
+
+
+func _ready():
+	tab_container.add_stylebox_override("panel", get_stylebox("Background", "EditorStyles"))
+	_update_settings()
+
+
+func _update_settings() -> void:
+	var editor_scale: float = editor_interface.get_editor_scale()
+	rect_min_size = Vector2(0, tabbar_container.rect_size.y + 182) * editor_scale
+
+	# Use the same policy as editor scene tabs.
+	tabs.tab_close_display_policy = (
+		Tabs.CLOSE_BUTTON_SHOW_ALWAYS
+		if editor_settings.get_setting("interface/scene_tabs/always_show_close_button")
+		else Tabs.CLOSE_BUTTON_SHOW_ACTIVE_ONLY
+	)
+
+	_update_terminal_tabs()
+
+
+func _update_terminal_tabs():
+	# Wait a couple of frames to allow everything to resize before updating.
+	yield(get_tree(), "idle_frame")
+	yield(get_tree(), "idle_frame")
+
+	if tabs.get_offset_buttons_visible():
+		# Move add button to fixed position on the tabbar.
+		if add_button.get_parent() == tabs:
+			add_button.rect_position = Vector2.ZERO
+			tabs.remove_child(add_button)
+			tabbar_container.add_child(add_button)
+			tabbar_container.move_child(add_button, 0)
+	else:
+		# Move add button after last tab.
+		if add_button.get_parent() == tabbar_container:
+			tabbar_container.remove_child(add_button)
+			tabs.add_child(add_button)
+		var last_tab := Rect2()
+		if tabs.get_tab_count() > 0:
+			last_tab = tabs.get_tab_rect(tabs.get_tab_count() - 1)
+		add_button.rect_position = Vector2(
+			last_tab.position.x + last_tab.size.x + 3, last_tab.position.y
+		)
+
+	# Make sure we still own the button, so it gets saved with our scene.
+	add_button.owner = self
+
+
+func _on_AddButton_pressed():
+	var shell = OS.get_environment("SHELL") if OS.has_environment("SHELL") else "sh"
+	var terminal := EditorTerminal.instance()
+	tabs.add_tab(shell.get_file())
+	terminal.editor_settings = editor_settings
+	terminal.set_anchors_preset(PRESET_WIDE)
+	tab_container.add_child(terminal)
+	terminal.pty.fork(shell)
+	terminal.grab_focus()
+	tabs.current_tab = tabs.get_tab_count() - 1
+	tab_container.current_tab = tabs.current_tab
+	_update_terminal_tabs()
+
+
+func _on_Tabs_tab_changed(tab_index):
+	tab_container.current_tab = tab_index
+	tab_container.get_child(tab_index).grab_focus()
+
+
+func _on_Tabs_tab_close(tab_index):
+	tabs.remove_tab(tab_index)
+	tab_container.get_child(tab_index).queue_free()
+	_update_terminal_tabs()
+
+
+func _notification(what):
+	if not ready:
+		return
+
+	match what:
+		EditorSettings.NOTIFICATION_EDITOR_SETTINGS_CHANGED:
+			_update_settings()
+			_update_terminal_tabs()
+		NOTIFICATION_RESIZED:
+			_update_terminal_tabs()
+		NOTIFICATION_WM_FOCUS_IN:
+			_update_terminal_tabs()

addons/godot_xterm/editor_plugins/terminal/terminal_panel.tscn

@@ -0,0 +1,100 @@
+[gd_scene load_steps=7 format=2]
+
+[ext_resource path="res://addons/godot_xterm/editor_plugins/terminal/terminal_panel.gd" type="Script" id=1]
+
+[sub_resource type="Image" id=6]
+data = {
+"data": PoolByteArray( 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ),
+"format": "LumAlpha8",
+"height": 16,
+"mipmaps": false,
+"width": 16
+}
+
+[sub_resource type="ImageTexture" id=2]
+flags = 4
+flags = 4
+image = SubResource( 6 )
+size = Vector2( 16, 16 )
+
+[sub_resource type="StyleBoxTexture" id=3]
+texture = SubResource( 2 )
+region_rect = Rect2( 0, 0, 16, 16 )
+margin_left = 2.0
+margin_right = 2.0
+margin_top = 2.0
+margin_bottom = 2.0
+
+[sub_resource type="Image" id=7]
+data = {
+"data": PoolByteArray( 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 255, 224, 224, 224, 255, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 224, 224, 224, 0, 224, 224, 224, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ),
+"format": "RGBA8",
+"height": 16,
+"mipmaps": false,
+"width": 16
+}
+
+[sub_resource type="ImageTexture" id=5]
+flags = 0
+flags = 0
+image = SubResource( 7 )
+size = Vector2( 16, 16 )
+
+[node name="Panel" type="Panel"]
+anchor_right = 1.0
+anchor_bottom = 1.0
+margin_top = -3.0
+rect_min_size = Vector2( 0, 34 )
+custom_styles/panel = SubResource( 3 )
+script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="VBoxContainer" type="VBoxContainer" parent="."]
+anchor_right = 1.0
+anchor_bottom = 1.0
+rect_min_size = Vector2( 0, 24 )
+custom_constants/separation = 0
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="TabbarContainer" type="HBoxContainer" parent="VBoxContainer"]
+margin_right = 1024.0
+margin_bottom = 24.0
+
+[node name="Tabs" type="Tabs" parent="VBoxContainer/TabbarContainer"]
+margin_right = 1024.0
+margin_bottom = 24.0
+size_flags_horizontal = 3
+tab_align = 0
+tab_close_display_policy = 1
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="AddButton" type="ToolButton" parent="VBoxContainer/TabbarContainer/Tabs"]
+margin_left = 3.0
+margin_right = 31.0
+margin_bottom = 24.0
+hint_tooltip = "Add a new scene."
+icon = SubResource( 5 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="TabContainer" type="TabContainer" parent="VBoxContainer"]
+margin_top = 24.0
+margin_right = 1024.0
+margin_bottom = 603.0
+rect_clip_content = true
+size_flags_vertical = 3
+custom_styles/panel = SubResource( 3 )
+custom_constants/top_margin = 0
+custom_constants/side_margin = 0
+tabs_visible = false
+
+[connection signal="tab_changed" from="VBoxContainer/TabbarContainer/Tabs" to="." method="_on_Tabs_tab_changed"]
+[connection signal="tab_close" from="VBoxContainer/TabbarContainer/Tabs" to="." method="_on_Tabs_tab_close"]
+[connection signal="pressed" from="VBoxContainer/TabbarContainer/Tabs/AddButton" to="." method="_on_AddButton_pressed"]

addons/godot_xterm/native/godotxtermnative.gdnlib

@@ -3,7 +3,7 @@
 singleton=false
 load_once=true
 symbol_prefix="godot_"
-reloadable=true
+reloadable=false
 
 [entry]
 

addons/godot_xterm/nodes/terminal/terminal.gd

@@ -108,6 +108,7 @@ func _ready():
 
 
 func _refresh():
+	_screen.update()
 	if update_mode == UpdateMode.AUTO:
 		_native_terminal.update_mode = UpdateMode.ALL_NEXT_FRAME
 

addons/godot_xterm/plugin.gd

@@ -3,6 +3,7 @@ extends EditorPlugin
 
 var pty_supported := OS.get_name() in ["X11", "Server", "OSX"]
 var asciicast_import_plugin
+var terminal_panel: Control
 
 
 func _enter_tree():
@@ -23,6 +24,9 @@ func _enter_tree():
 			"X11", "Server", "OSX":
 				pty_script = load("res://addons/godot_xterm/nodes/pty/unix/pty_unix.gd")
 		add_custom_type("PTY", "Node", pty_script, pty_icon)
+		terminal_panel = preload("./editor_plugins/terminal/terminal_panel.tscn").instance()
+		terminal_panel.editor_interface = get_editor_interface()
+		add_control_to_bottom_panel(terminal_panel, "Terminal")
 
 
 func _exit_tree():
@@ -34,3 +38,5 @@ func _exit_tree():
 
 	if pty_supported:
 		remove_custom_type("PTY")
+		remove_control_from_bottom_panel(terminal_panel)
+		terminal_panel.free()