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use std::borrow::Cow;
use soft_ascii_string::{ SoftAsciiStr, SoftAsciiString};
use grammar::is_token_char;
use percent_encoding::{
EncodeSet,
percent_encode
};
#[derive(Debug, Eq, PartialEq, Clone, Copy, Hash)]
struct MimeParamEncodingSet;
impl EncodeSet for MimeParamEncodingSet {
fn contains(&self, byte: u8) -> bool {
//if it is in the encoding set we need to encode it
//which we need to to if it is _not_ a token char
!is_token_char(byte as char)
}
}
/// percent encodes a byte sequence so that it can be used
/// in a RFC 2231 conform encoded mime header parameter
pub fn percent_encode_param_value<'a, R>(input: &'a R) -> Cow<'a, SoftAsciiStr>
where R: ?Sized+AsRef<[u8]>
{
let cow: Cow<'a, str> = percent_encode(input.as_ref(), MimeParamEncodingSet).into();
match cow {
Cow::Owned(o) =>
//SAFE: MimeParamEncodingSet makes all non-us-ascii bytes encoded AND
// percent_encoding::percent_encode always only produces ascii anyway
Cow::Owned(SoftAsciiString::from_unchecked(o)),
Cow::Borrowed(b) =>
Cow::Borrowed(SoftAsciiStr::from_unchecked(b))
}
}
#[cfg(test)]
mod test {
use std::borrow::Cow;
use super::*;
#[test]
fn encode_simple() {
let input = "this is tüxt";
let res = percent_encode_param_value(input);
assert_eq!("this%20is%20t%C3%BCxt", res.as_str());
}
#[test]
fn no_encode_no_alloc() {
let input = "full_valid";
let res = percent_encode_param_value(input);
assert_eq!(res, Cow::Borrowed(input));
}
}
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