mailbox 0.2.0

MBOX reader.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130

//            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
//                    Version 2, December 2004
//
// Copyleft (ↄ) meh. <meh@schizofreni.co> | http://meh.schizofreni.co
//
// Everyone is permitted to copy and distribute verbatim or modified
// copies of this license document, and changing it is allowed as long
// as the name is changed.
//
//            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
//   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
//
//  0. You just DO WHAT THE FUCK YOU WANT TO.

use std::ops::Range;
use std::io;
use std::rc::Rc;
use std::borrow::Cow;
use owning_ref::OwningRef;
use nom::IResult;
use casing::Casing;

/// A header in an email.
#[derive(Eq, PartialEq, Clone, Debug)]
pub struct Header {
	inner: Item,

	key:   Range<usize>,
	value: Range<usize>,
}

/// A header item.
///
/// Note this is the same `String` that was allocated by the `stream::Lines` iterator,
/// this means there are no allocations or copies when accessing `key()` and `value()`.
pub type Item = OwningRef<Rc<String>, str>;

#[inline(always)]
pub(crate) fn item<T: Into<String>>(string: T) -> Item {
	OwningRef::new(Rc::new(string.into())).map(|s| s.as_ref())
}

impl Header {
	#[inline]
	pub(crate) fn ranges<T: AsRef<[u8]>>(string: T) -> io::Result<(Range<usize>, Range<usize>)> {
		let string = string.as_ref();

		if let IResult::Done(_, (key, value)) = parser::parse(string) {
			let k = key.as_ptr() as usize - string.as_ptr() as usize;
			let v = value.as_ptr() as usize - string.as_ptr() as usize;

			Ok((
				Range { start: k, end: k + key.len() },
				Range { start: v, end: v + value.len() },
			))
		}
		else {
			Err(io::Error::new(io::ErrorKind::InvalidInput, "invalid header"))
		}
	}

	/// Create a new `Header` from the given `String`.
	#[inline]
	pub fn new<T: Into<Vec<u8>>>(string: T) -> io::Result<Self> {
		let string       = string.into();
		let (key, value) = try!(Header::ranges(&string));

		Ok(Header {
			// The parser verifies the content is US-ASCII, so it's safe.
			inner: item(unsafe { String::from_utf8_unchecked(string) }),

			key:   key,
			value: value,
		})
	}

	/// The header key in the proper case.
	///
	/// Note that this allocates only if the key is not already in the proper case.
	#[inline]
	pub fn key(&self) -> Item {
		match (&self.inner[Range { start: self.key.start, end: self.key.end }]).header(Default::default()) {
			Cow::Borrowed(_)   => self.inner.clone().map(|s| &s[Range { start: self.key.start, end: self.key.end }]),
			Cow::Owned(string) => OwningRef::new(Rc::new(string)).map(|s| s.as_ref()),
		}
	}

	/// The header value.
	#[inline]
	pub fn value(&self) -> Item {
		self.inner.clone().map(|s| &s[Range { start: self.value.start, end: self.value.end }])
	}
}

mod parser {
	use util::parser::{is_ws, is_printable_no_colon, is_printable_or_ws};

	named!(pub parse(&[u8]) -> (&[u8], &[u8]),
		do_parse!(
			key: key >>
			char!(':') >>
			take_while!(is_ws) >>
			value: value >>
			eof!() >>

			(key, value)));

	named!(key(&[u8]) -> &[u8],
		take_while!(is_printable_no_colon));

	named!(value(&[u8]) -> &[u8],
		take_while!(is_printable_or_ws));
}

#[cfg(test)]
mod test {
	use super::*;

	#[test]
	fn ok() {
		let v = Header::new("From: meh. <meh@schizofreni.co>").unwrap();
		assert_eq!(&*v.key(), "From");
		assert_eq!(&*v.value(), "meh. <meh@schizofreni.co>");
	}

	#[test]
	fn fail() {
		assert!(Header::new("From foo@example.com").is_err());
	}
}