bevy_yoleck/
entity_upgrading.rs

1use std::collections::BTreeMap;
2
3use bevy::prelude::*;
4
5use crate::YoleckRawLevel;
6
7/// Support upgrading of entities when the layout of the Yoleck entities and components change.
8///
9/// ```no_run
10/// # use bevy::prelude::*;
11/// # use bevy_yoleck::prelude::*;
12/// # let mut app = App::new();
13/// app.add_plugins(YoleckEntityUpgradingPlugin {
14///     app_format_version: 5,
15/// });
16///
17/// // The newest upgrade, from 4 to 5
18/// app.add_yoleck_entity_upgrade_for(5, "Foo", |data| {
19///     let mut old_data = data.as_object_mut().unwrap().remove("OldFooComponent").unwrap();
20///     data["NewFooComponent"] = old_data;
21/// });
22///
23/// // Some older upgrade, from 2 to 3
24/// app.add_yoleck_entity_upgrade(3, |_type_name, data| {
25///     if let Some(component_data) = data.get_mut("Bar") {
26///         component_data["some_new_field"] = 42.into();
27///     }
28/// });
29/// ```
30pub struct YoleckEntityUpgradingPlugin {
31    /// The current version of the app data.
32    ///
33    /// If `YoleckEntityUpgradingPlugin` is not added, the current version is considered 0
34    /// ("unversioned")
35    pub app_format_version: usize,
36}
37
38impl Plugin for YoleckEntityUpgradingPlugin {
39    fn build(&self, app: &mut App) {
40        app.insert_resource(YoleckEntityUpgrading {
41            app_format_version: self.app_format_version,
42            upgrade_functions: Default::default(),
43        });
44    }
45}
46
47#[derive(Resource)]
48pub(crate) struct YoleckEntityUpgrading {
49    pub app_format_version: usize,
50    #[allow(clippy::type_complexity)]
51    pub upgrade_functions:
52        BTreeMap<usize, Vec<Box<dyn 'static + Send + Sync + Fn(&str, &mut serde_json::Value)>>>,
53}
54
55impl YoleckEntityUpgrading {
56    pub fn upgrade_raw_level_file(&self, levels_file: &mut YoleckRawLevel) {
57        let first_target_version = levels_file.0.app_format_version + 1;
58        for (target_version, upgrade_functions) in
59            self.upgrade_functions.range(first_target_version..)
60        {
61            for entity in levels_file.2.iter_mut() {
62                for function in upgrade_functions.iter() {
63                    function(&entity.header.type_name, &mut entity.data);
64                }
65            }
66            levels_file.0.app_format_version = *target_version;
67        }
68    }
69}