http_parser.rs

## http_parser.rs
//! http parser comparable to the http-parser found in attoparsec's examples.
//!
//! Reads data in the following format:
//!
//! ```text
//! GET /robot.txt HTTP/1.1
//! Host: localhost
//! Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
//!
//! ```

#[macro_use]
extern crate parser;

use parser::combinator::*;
use parser::monad::*;
use parser::parser::*;
use parser::Parser;
use parser::Input;
use parser::Error;

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

#[derive(Debug)]
struct Request<'a> {
    method:  &'a [u8],
    uri:     &'a [u8],
    version: &'a [u8],
}

#[derive(Debug)]
struct Header<'a> {
    name:  &'a [u8],
    value: Vec<&'a [u8]>,
}

fn is_token(c: u8) -> bool {
    // roughly follows the order of ascii chars: "\"(),/:;<=>?@[\\]{} \t"
    c < 128 && c > 32 && c != b'\t' && c != b'"' && c != b'(' && c != b')' &&
        c != b',' && c != b'/' && !(c > 57 && c < 65) && !(c > 90 && c < 94) &&
        c != b'{' && c != b'}'
}

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<'a>(p: Input<'a, u8>) -> Parser<'a, u8, u8, Error<u8>> {
    or(p, |p| mdo!{p,
        char(b'\r');
        char(b'\n');

        ret u8, Error<u8>: b'\r'
    }, |p| char(p, b'\n'))
}

fn http_version<'a>(p: Input<'a, u8>) -> Parser<'a, u8, &'a [u8], Error<u8>> {
    mdo!{p,
                  string(b"HTTP/");
        version = take_while1(is_http_version);

        ret version
    }
}

#[inline(always)]
fn request_line<'a>(p: Input<'a, u8>) -> Parser<'a, u8, Request<'a>, Error<u8>> {
    mdo!{p,
        method  = take_while1(is_token);
                  take_while1(is_space);
        uri     = take_while1(is_not_space);
                  take_while1(is_space);
        version = http_version;

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

fn message_header_line<'a>(p: Input<'a, u8>) -> Parser<'a, u8, &'a [u8], Error<u8>> {
    mdo!{p,
               take_while1(is_horizontal_space);
        line = take_till(is_end_of_line);
               end_of_line;

        ret line
    }
}

fn message_header<'a>(p: Input<'a, u8>) -> Parser<'a, u8, Header, Error<u8>> {
    mdo!{p,
        name  = take_while1(is_token);
                char(b':');
        lines = many1(message_header_line);

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

#[inline(always)]
fn request<'a>(p: Input<'a, u8>) -> Parser<'a, u8, (Request, Vec<Header>), Error<u8>> {
    mdo!{p,
        r = request_line;
            end_of_line;
        h = many(message_header);
            end_of_line;

        ret (r, h)
    }
}

fn main() {
    let mut contents: Vec<u8> = Vec::new();

    {
        use std::io::Read;

        let mut file = File::open(env::args().nth(1).expect("File to read")).ok().expect("Failed to open file");

        let _ = file.read_to_end(&mut contents).unwrap();
    }

    let i = parser::Iter::new(&contents, request);

    println!("num: {}", i.count());
}