build.rs

extern crate phf_codegen;

use std::env;
use std::fs::File;
use std::io::BufRead;
use std::io::{BufReader, BufWriter, Write};
use std::path::Path;

fn titlecase_word(word: &str) -> String {
    word.chars()
        .enumerate()
        .map(|(i, c)| {
            if i == 0 {
                c.to_uppercase().collect::<String>()
            } else {
                c.to_lowercase().collect::<String>()
            }
        })
        .collect()
}

fn main() {
    let path_txt =
        Path::new(&env::var("CARGO_MANIFEST_DIR").unwrap()).join("scripts/tls-ciphersuites.txt");
    let display = path_txt.display();
    let file = match File::open(&path_txt) {
        // The `description` method of `io::Error` returns a string that
        // describes the error
        Err(why) => panic!("couldn't open {}: {}", display, why),
        Ok(file) => file,
    };
    let f = BufReader::new(file);

    let path = Path::new(&env::var("OUT_DIR").unwrap()).join("codegen.rs");
    let mut file = BufWriter::new(File::create(&path).unwrap());

    let mut map = phf_codegen::Map::new();
    for line in f.lines() {
        let l = line.unwrap();
        let mut v: Vec<&str> = l.split(':').collect();

        if v[5].is_empty() {
            v[5] = "NULL"
        }

        let au = match v[3] {
            "SRP+DSS" => String::from("Srp_Dss"),
            "SRP+RSA" => String::from("Srp_Rsa"),
            _ => titlecase_word(v[3]).replace("+", "_"),
        };

        let enc = match v[4] {
            "3DES" => String::from("TripleDes"),
            "CHACHA20_POLY1305" => String::from("Chacha20_Poly1305"),
            _ => titlecase_word(v[4]),
        };

        let mac = String::from(match v[7] {
            "NULL" => "Null",
            "HMAC-MD5" => "HmacMd5",
            "HMAC-SHA1" => "HmacSha1",
            "HMAC-SHA256" => "HmacSha256",
            "HMAC-SHA384" => "HmacSha384",
            "HMAC-SHA512" => "HmacSha512",
            "AEAD" => "Aead",
            _ => panic!("Unknown mac {}", v[7]),
        });

        let prf = titlecase_word(v[9]);

        let key = u16::from_str_radix(v[0], 16).unwrap();
        let val = format!(
            r#"TlsCipherSuite{{
                name:"{}",
                id:TlsCipherSuiteID(0x{}),
                kx:TlsCipherKx::{},
                au:TlsCipherAu::{},
                enc:TlsCipherEnc::{},
                enc_mode:TlsCipherEncMode::{},
                enc_size:{},
                mac:TlsCipherMac::{},
                mac_size:{},
                prf: TlsPRF::{},
            }}"#,
            v[1],
            v[0],
            titlecase_word(v[2]), // kx
            au,                   // au
            enc,                  // enc
            titlecase_word(v[5]), // enc_mode
            v[6],                 // enc_key_size
            mac,                  // mac
            v[8],                 // mac_size
            prf,                  // prf
        )
        .clone();

        map.entry(key, val.as_str());
    }

    writeln!(
        &mut file,
        "pub static CIPHERS: phf::Map<u16, TlsCipherSuite> = {};",
        map.build()
    )
    .unwrap();
}