Merge pull request #124 from GDami/script-extensions-with-inheritance

Inheritance checks for script extensions

addons/mod_loader/mod_loader.gd

@@ -77,6 +77,16 @@ var mod_missing_dependencies := {}
 # Things to keep to ensure they are not garbage collected (used by `save_scene`)
 var _saved_objects := []
 
+# Store all extenders paths
+var script_extensions := []
+
+# Store vanilla classes for script extension sorting
+var loaded_vanilla_parents_cache := {}
+
+# Set to false after _init()
+# Helps to decide whether a script extension should go through the _handle_script_extensions process
+var is_initializing := true
+
 
 # Main
 # =============================================================================
@@ -164,6 +174,12 @@ func _init() -> void:
 	ModLoaderUtils.log_debug_json_print("mod data", mod_data, LOG_NAME)
 
 	ModLoaderUtils.log_success("DONE: Completely finished loading mods", LOG_NAME)
+
+	_handle_script_extensions()
+
+	ModLoaderUtils.log_success("DONE: Installed all script extensions", LOG_NAME)
+
+	is_initializing = false
 
 
 # Ensure ModLoader is the first autoload
@@ -463,25 +479,112 @@ func _init_mod(mod: ModData) -> void:
 	add_child(mod_main_instance, true)
 
 
-# Helpers
-# =============================================================================
+# Couple the extension paths with the parent paths and the extension's mod id
+# in a ScriptExtensionData resource
+func _handle_script_extensions()->void:
+	var script_extension_data_array := []
+	for extension_path in script_extensions:
+
+		if not File.new().file_exists(extension_path):
+			ModLoaderUtils.log_error("The child script path '%s' does not exist" % [extension_path], LOG_NAME)
+			continue 
+
+		var child_script = ResourceLoader.load(extension_path)
+
+		var mod_id:String = extension_path.trim_prefix(UNPACKED_DIR).get_slice("/", 0)
+
+		var parent_script:Script = child_script.get_base_script()
+		var parent_script_path:String = parent_script.resource_path
+
+		if not loaded_vanilla_parents_cache.keys().has(parent_script_path):
+			loaded_vanilla_parents_cache[parent_script_path] = parent_script
+
+		script_extension_data_array.push_back(
+			ScriptExtensionData.new(extension_path, parent_script_path, mod_id)
+		)
+
+	# Sort the extensions based on dependencies
+	script_extension_data_array = _sort_extensions_from_load_order(script_extension_data_array)
+
+	# Inheritance is more important so this called last
+	script_extension_data_array.sort_custom(self, "check_inheritances")
+
+	# This saved some bugs in the past. 
+	loaded_vanilla_parents_cache.clear()
+
+	# Load and install all extensions
+	for extension in script_extension_data_array:
+		var script:Script = _apply_extension(extension.extension_path)
+		_reload_vanilla_child_classes_for(script)
+
+
+# Sort an array of ScriptExtensionData following the load order
+func _sort_extensions_from_load_order(extensions:Array)->Array:
+	var extensions_sorted := []
+
+	for _mod_data in mod_load_order:
+		for script in extensions:
+			if script.mod_id == _mod_data.dir_name:
+				extensions_sorted.push_front(script)
+
+	return extensions_sorted
+
+
+# Inheritance sorting
+# Go up extension_a's inheritance tree to find if any parent shares the same vanilla path as extension_b
+func _check_inheritances(extension_a:ScriptExtensionData, extension_b:ScriptExtensionData)->bool:
+	var a_child_script:Script
+
+	if loaded_vanilla_parents_cache.keys().has(extension_a.parent_script_path):
+		a_child_script = ResourceLoader.load(extension_a.parent_script_path)
+	else:
+		a_child_script = ResourceLoader.load(extension_a.parent_script_path)
+		loaded_vanilla_parents_cache[extension_a.parent_script_path] = a_child_script
+
+	var a_parent_script:Script = a_child_script.get_base_script()
+
+	if a_parent_script == null:
+		return true
+
+	var a_parent_script_path = a_parent_script.resource_path
+	if a_parent_script_path == extension_b.parent_script_path:
+		return false
+
+	else:
+		return _check_inheritances(ScriptExtensionData.new(extension_a.extension_path, a_parent_script_path, extension_a.mod_id), extension_b)
 
-# Helper functions to build mods
 
-# Add a script that extends a vanilla script. `child_script_path` should point
-# to your mod's extender script, eg "MOD/extensions/singletons/utils.gd".
-# Inside that extender script, it should include "extends {target}", where
-# {target} is the vanilla path, eg: `extends "res://singletons/utils.gd"`.
-# Note that your extender script doesn't have to follow the same directory path
-# as the vanilla file, but it's good practice to do so.
-func install_script_extension(child_script_path: String) -> void:
-	# Check path to file exists
-	if not File.new().file_exists(child_script_path):
-		ModLoaderUtils.log_error("The child script path '%s' does not exist" % [child_script_path], LOG_NAME)
+# Reload all children classes of the vanilla class we just extended
+# Calling reload() the children of an extended class seems to allow them to be extended
+# e.g if B is a child class of A, reloading B after apply an extender of A allows extenders of B to properly extend B, taking A's extender(s) into account
+func _reload_vanilla_child_classes_for(script:Script)->void:
+
+	if script == null:
 		return
+	var current_child_classes := []
+	var actual_path:String = script.get_base_script().resource_path
+	var classes:Array = ProjectSettings.get_setting("_global_script_classes")
+
+	for _class in classes:
+		if _class.path == actual_path:
+			current_child_classes.push_back(_class)
+			break
+
+	for _class in current_child_classes:
+		for child_class in classes:
+
+			if child_class.base == _class.class:
+				load(child_class.path).reload()
 
-	var child_script := ResourceLoader.load(child_script_path)
 
+func _apply_extension(extension_path)->Script:
+	# Check path to file exists
+	if not File.new().file_exists(extension_path):
+		ModLoaderUtils.log_error("The child script path '%s' does not exist" % [extension_path], LOG_NAME)
+		return null
+
+	var child_script:Script = ResourceLoader.load(extension_path)
+
 	# Force Godot to compile the script now.
 	# We need to do this here to ensure that the inheritance chain is
 	# properly set up, and multiple mods can chain-extend the same
@@ -491,10 +594,35 @@ func install_script_extension(child_script_path: String) -> void:
 	# The actual instance is thrown away.
 	child_script.new()
 
-	var parent_script = child_script.get_base_script()
-	var parent_script_path: String = parent_script.resource_path
-	ModLoaderUtils.log_info("Installing script extension: %s <- %s" % [parent_script_path, child_script_path], LOG_NAME)
+	var parent_script:Script = child_script.get_base_script()
+	var parent_script_path:String = parent_script.resource_path
+	ModLoaderUtils.log_info("Installing script extension: %s <- %s" % [parent_script_path, extension_path], LOG_NAME)
 	child_script.take_over_path(parent_script_path)
+
+	return child_script
+
+
+# Helpers
+# =============================================================================
+
+# Helper functions to build mods
+
+# Add a script that extends a vanilla script. `child_script_path` should point
+# to your mod's extender script, eg "MOD/extensions/singletons/utils.gd".
+# Inside that extender script, it should include "extends {target}", where
+# {target} is the vanilla path, eg: `extends "res://singletons/utils.gd"`.
+# Note that your extender script doesn't have to follow the same directory path
+# as the vanilla file, but it's good practice to do so.
+func install_script_extension(child_script_path:String):
+
+	# If this is called during initialization, add it with the other 
+	# extensions to be installed taking inheritance chain into account
+	if is_initializing:
+		script_extensions.push_back(child_script_path)
+
+	# If not, apply the extension directly
+	else:
+		_apply_extension(child_script_path)
 
 
 # Register an array of classes to the global scope, since Godot only does that in the editor.

addons/mod_loader/script_extension_data.gd

@@ -0,0 +1,20 @@
+class_name ScriptExtensionData
+extends Resource
+
+# Stores all Data defining a script extension
+
+# Full path to the extension file
+var extension_path:String
+
+# Full path to the vanilla script extended
+var parent_script_path:String
+
+# Mod requesting the extension
+var mod_id:String
+
+
+func _init(p_extension_path:String, p_parent_script_path:String, p_mod_id:String):
+	extension_path = p_extension_path
+	parent_script_path = p_parent_script_path
+	mod_id = p_mod_id
+