refactor(M03): extract WMO scene resource cache state

src/render/wmo/wmo_scene_resource_cache_state.gd

@@ -0,0 +1,134 @@
+class_name WmoSceneResourceCacheState
+extends RefCounted
+
+## Owns validated cached-WMO PackedScenes and their load state. File limits,
+## ResourceLoader I/O and scene-cache validation remain caller responsibilities.
+
+var _scenes_by_normalized_path: Dictionary = {}
+var _missing_normalized_paths: Dictionary = {}
+var _request_cache_paths_by_normalized_path: Dictionary = {}
+
+
+## Returns the validated PackedScene for a normalized WMO path, or null.
+func scene_for(normalized_relative_path: String) -> PackedScene:
+	if normalized_relative_path.is_empty():
+		return null
+	return _scenes_by_normalized_path.get(normalized_relative_path) as PackedScene
+
+
+## Returns whether a validated PackedScene is cached for the normalized path.
+func contains_scene(normalized_relative_path: String) -> bool:
+	return (
+		not normalized_relative_path.is_empty()
+		and _scenes_by_normalized_path.has(normalized_relative_path)
+	)
+
+
+## Returns whether the normalized path is in the negative cache.
+func is_missing(normalized_relative_path: String) -> bool:
+	return (
+		not normalized_relative_path.is_empty()
+		and _missing_normalized_paths.has(normalized_relative_path)
+	)
+
+
+## Returns whether the normalized path has a pending threaded load request.
+func has_request(normalized_relative_path: String) -> bool:
+	return (
+		not normalized_relative_path.is_empty()
+		and _request_cache_paths_by_normalized_path.has(normalized_relative_path)
+	)
+
+
+## Records one loader-started request. Occupied or empty paths are rejected.
+func remember_request(normalized_relative_path: String, cache_path: String) -> bool:
+	if normalized_relative_path.is_empty() or cache_path.is_empty():
+		return false
+	if _has_any_state(normalized_relative_path):
+		return false
+	_request_cache_paths_by_normalized_path[normalized_relative_path] = cache_path
+	return true
+
+
+## Records an absent, oversize or request-start failure without requiring a
+## pending request. Occupied and empty paths are rejected.
+func mark_missing(normalized_relative_path: String) -> bool:
+	if normalized_relative_path.is_empty() or _has_any_state(normalized_relative_path):
+		return false
+	_missing_normalized_paths[normalized_relative_path] = true
+	return true
+
+
+## Returns a detached normalized-path to cache-path snapshot for loader polling.
+func request_paths_snapshot() -> Dictionary:
+	return _request_cache_paths_by_normalized_path.duplicate()
+
+
+## Completes a pending request with a caller-validated PackedScene.
+func complete_request_with_scene(
+		normalized_relative_path: String,
+		validated_scene: PackedScene
+) -> bool:
+	if (
+			normalized_relative_path.is_empty()
+			or validated_scene == null
+			or not _request_cache_paths_by_normalized_path.has(normalized_relative_path)
+	):
+		return false
+	_request_cache_paths_by_normalized_path.erase(normalized_relative_path)
+	_missing_normalized_paths.erase(normalized_relative_path)
+	_scenes_by_normalized_path[normalized_relative_path] = validated_scene
+	return true
+
+
+## Completes a pending request as missing after load or validation failure.
+func complete_request_as_missing(normalized_relative_path: String) -> bool:
+	if (
+			normalized_relative_path.is_empty()
+			or not _request_cache_paths_by_normalized_path.has(normalized_relative_path)
+	):
+		return false
+	_request_cache_paths_by_normalized_path.erase(normalized_relative_path)
+	_scenes_by_normalized_path.erase(normalized_relative_path)
+	_missing_normalized_paths[normalized_relative_path] = true
+	return true
+
+
+## Clears pending and negative state while retaining validated PackedScenes.
+func clear_transient_state() -> void:
+	_request_cache_paths_by_normalized_path.clear()
+	_missing_normalized_paths.clear()
+
+
+## Releases every cached scene and transient entry. Safe to call repeatedly.
+func clear_all() -> void:
+	_scenes_by_normalized_path.clear()
+	clear_transient_state()
+
+
+## Returns the number of pending threaded load requests.
+func pending_request_count() -> int:
+	return _request_cache_paths_by_normalized_path.size()
+
+
+## Returns detached, sorted scalar keys without exposing PackedScene references.
+func diagnostic_snapshot() -> Dictionary:
+	var scene_paths: Array = _scenes_by_normalized_path.keys()
+	var missing_paths: Array = _missing_normalized_paths.keys()
+	var request_paths: Array = _request_cache_paths_by_normalized_path.keys()
+	scene_paths.sort()
+	missing_paths.sort()
+	request_paths.sort()
+	return {
+		"scene_paths": scene_paths.duplicate(),
+		"missing_paths": missing_paths.duplicate(),
+		"request_paths": request_paths.duplicate(),
+	}
+
+
+func _has_any_state(normalized_relative_path: String) -> bool:
+	return (
+		_scenes_by_normalized_path.has(normalized_relative_path)
+		or _missing_normalized_paths.has(normalized_relative_path)
+		or _request_cache_paths_by_normalized_path.has(normalized_relative_path)
+	)