impl Trait with Input trait version of the chomp example HTTP-parser

http_parser.rs

#![feature(conservative_impl_trait)]

#[macro_use]
extern crate chomp;
extern crate memmap;

use std::fs::File;
use std::env;

use chomp::types::{Input, Parser};
use chomp::monad::*;
use chomp::parsers::*;
use chomp::combinators::*;

#[derive(Debug)]
struct Request<B> {
    method:  B,
    uri:     B,
    version: B,
}

#[derive(Debug)]
struct Header<B> {
    name:  B,
    value: Vec<B>,
}

fn is_token(c: u8) -> bool {
    match c {
        128...255 => false,
        0...31    => false,
        b'('      => false,
        b')'      => false,
        b'<'      => false,
        b'>'      => false,
        b'@'      => false,
        b','      => false,
        b';'      => false,
        b':'      => false,
        b'\\'     => false,
        b'"'      => false,
        b'/'      => false,
        b'['      => false,
        b']'      => false,
        b'?'      => false,
        b'='      => false,
        b'{'      => false,
        b'}'      => false,
        b' '      => false,
        _         => true,
    }
}

fn is_horizontal_space(c: u8) -> bool { c == b' ' || c == b'\t' }
fn is_space(c: u8)            -> bool { c == b' ' }
fn is_not_space(c: u8)        -> bool { c != b' ' }
fn is_end_of_line(c: u8)      -> bool { c == b'\r' || c == b'\n' }
fn is_http_version(c: u8)     -> bool { c >= b'0' && c <= b'9' || c == b'.' }

fn end_of_line<I: Input<Token=u8>>() -> impl Parser<I, Output=u8, Error=Error<u8>> {
    parse!{(token(b'\r') <|> ret b'\0') >> token(b'\n')}
}

fn message_header_line<I: Input<Token=u8>>() -> impl Parser<I, Output=I::Buffer, Error=Error<u8>> {
    parse!{
                   take_while1(is_horizontal_space);
        let line = take_till(is_end_of_line);
                   end_of_line();

        ret line
    }
}

fn message_header<I: Input<Token=u8>>() -> impl Parser<I, Output=Header<I::Buffer>, Error=Error<u8>> {
    parse!{
        let name  = take_while1(is_token);
                    token(b':');
        let lines = many_from(1, message_header_line);

        ret Header {
            name:  name,
            value: lines,
        }
    }
}

fn http_version<I: Input<Token=u8>>() -> impl Parser<I, Output=I::Buffer, Error=Error<u8>> {
    parse!{
        string(b"HTTP/");
        take_while1(is_http_version)
    }
}

fn request_line<I: Input<Token=u8>>() -> impl Parser<I, Output=Request<I::Buffer>, Error=Error<u8>> {
    parse!{
        let method  = take_while1(is_token);
                      take_while1(is_space);
        let uri     = take_while1(is_not_space);
                      take_while1(is_space);
        let version = http_version();

        ret Request {
            method:  method,
            uri:     uri,
            version: version,
        }
    }
}

#[inline(never)]
fn request<I: Input<Token=u8>>() -> impl Parser<I, Output=(Request<I::Buffer>, Vec<Header<I::Buffer>>), Error=Error<u8>>
  where I::Buffer: ::std::ops::Deref<Target=[u8]> {
    parse!{
        let r = request_line();
                end_of_line();
        let h = many(message_header);
                end_of_line();

        ret (r, h)
    }
}

fn main() {
    let contents = memmap::Mmap::open_path(env::args().nth(1).expect("File to read"), memmap::Protection::Read).expect("Failed to open file");

    let mut n    = 0;
    let mut data = unsafe { contents.as_slice() };

    loop {
        match request().parse(data) {
            (i, Ok(_)) => {
                n = n + 1;

                data = i;
            },
            (_, Err(e)) => {
                panic!("Error: {:?}", e);
            },
        }

        if data.is_empty() {
            break;
        }
    }

    println!("num: {}", n);
}