rust_utils/config.rs
1//! Basic config API
2//!
3//! Contains a special trait that allows a type to have an associated config file
4
5use serde::{Deserialize, Serialize};
6use std::{
7 env, fs,
8 io::Result as IoResult,
9 path::PathBuf
10};
11use ron::ser::PrettyConfig;
12
13/// The type of config file we are using
14#[derive(Clone, Copy)]
15pub enum ConfigType {
16 Toml,
17 Ron
18}
19
20/// The `Config` trait allows a type to have an associated config file
21///
22/// Requires the [`Default`], [`Serialize`], and [`Deserialize`] traits (can be derived) to be implemented
23pub trait Config: Serialize + Default + for <'de> Deserialize<'de> {
24 /// This constant must be set to the file name of the config file
25 const FILE_NAME: &'static str;
26
27 /// This constant is the type of config
28 ///
29 /// Defaults to TOML
30 const TYPE: ConfigType = ConfigType::Toml;
31
32 /// Returns the save directory of the config file.
33 ///
34 /// This method must be defined
35 fn get_save_dir() -> PathBuf;
36
37 /// Returns the full path of the config file
38 fn get_full_path() -> PathBuf {
39 Self::get_save_dir().join(Self::FILE_NAME)
40 }
41
42 /// Load from the config file
43 ///
44 /// Returns the defaults if the file does not exist or is corrupted
45 ///
46 /// Panics if the config directory cannot be created
47 #[track_caller]
48 fn load() -> Self {
49 let file_str = if let Ok(file) = fs::read_to_string(Self::get_full_path()) {
50 file
51 }
52 else {
53 let config = Self::default();
54 config.save().expect("Unable to load config!");
55 return config;
56 };
57
58 match Self::TYPE {
59 ConfigType::Toml => {
60 if let Ok(cfg) = toml::from_str(&file_str) {
61 cfg
62 }
63 else { Self::default() }
64 }
65
66 ConfigType::Ron => {
67 if let Ok(cfg) = ron::from_str(&file_str) {
68 cfg
69 }
70 else { Self::default() }
71 }
72 }
73 }
74
75 /// Save to the config file
76 ///
77 /// It is recommended to call this in every method that has &mut self as an argument!
78 #[track_caller]
79 fn save(&self) -> IoResult<()> {
80 let save_str = match Self::TYPE {
81 ConfigType::Toml => toml::to_string_pretty(&self).unwrap(),
82 ConfigType::Ron => {
83 let cfg = PrettyConfig::default();
84 ron::ser::to_string_pretty(&self, cfg).unwrap()
85 }
86 };
87
88 fs::create_dir_all(Self::get_save_dir())?;
89 fs::write(Self::get_full_path(), save_str)
90 }
91
92 /// Helper function to get the user's config root folder (normally `$HOME/.config` on most unix-like systems)
93 ///
94 /// Panics if your user does not have a home folder
95 #[track_caller]
96 fn get_config_root() -> PathBuf {
97 if let Ok(xdg_config_home) = env::var("XDG_CONFIG_HOME") {
98 xdg_config_home.into()
99 }
100 else {
101 PathBuf::from(
102 env::var("HOME").expect("Where is your home folder?!")
103 )
104 .join(".config")
105 }
106 }
107}