build.rs

use lazy_static::lazy_static;
use regex::Regex;
use std::collections::HashMap;
use std::env;
use std::error::Error;
use std::fs::{self,File};
use std::path::Path;
use tera::{Context,Tera};

fnmain() -> Result<(),Box<dynError>>{
#[cfg(windows)]
{
letmut res = winres::WindowsResource::new();
 res.set_icon("assets/onefetch.ico");
 res.compile()?;
}
let out_dir = env::var("OUT_DIR").expect("No OUT_DIR variable.");
letmut tera = Tera::default();
 tera.register_filter("strip_color_tokens", strip_color_tokens_filter);
 tera.register_filter("hex_to_rgb", hex_to_rgb_filter);

let lang_data: serde_json::Value = serde_yaml::from_reader(File::open("languages.yaml")?)?;

let output_path = Path::new(&out_dir).join("language.rs");

let rust_code = tera.render_str(
&std::fs::read_to_string("src/info/langs/language.tera")?,
&Context::from_value(serde_json::json!({"languages": lang_data,}))?,
)?;
 fs::write(output_path, rust_code)?;

Ok(())
}

/// Strips out `{n}` from the given string.
fnstrip_color_tokens_filter(
value:&tera::Value,
_args:&HashMap<String, tera::Value>,
) -> tera::Result<tera::Value>{
lazy_static!{
static ref COLOR_INDEX_REGEX:Regex = Regex::new(r"\{\d+\}").unwrap();
}
let s = match value {
 tera::Value::String(s) => s,
 _ => returnErr(tera::Error::msg("expected string")),
};
Ok(tera::Value::String(
COLOR_INDEX_REGEX.replace_all(s,"").to_string(),
))
}

fnhex_to_rgb_filter(
value:&tera::Value,
_args:&HashMap<String, tera::Value>,
) -> tera::Result<tera::Value>{
let hex_string = match value {
 tera::Value::String(s) => s,
 _ => returnErr(tera::Error::msg("expected string")),
};
let hex_string = match hex_string.strip_prefix('#'){
Some(s) => s,
None => returnErr(tera::Error::msg("expected hex string starting with `#`")),
};
if hex_string.len() != 6{
returnErr(tera::Error::msg("expected a 6 digit hex string"));
}
let channel_bytes = match u32::from_str_radix(hex_string,16){
Ok(n) => n,
Err(_) => returnErr(tera::Error::msg("expected a valid hex string")),
};
let r = (channel_bytes >> 16)&0xFF;
let g = (channel_bytes >> 8)&0xFF;
let b = channel_bytes &0xFF;

Ok(serde_json::json!({
"r": r,
"g": g,
"b": b,
}))
}