ntex-files 3.2.0

use language_tags::LanguageTag;
use std::fmt::{self, Display};
use std::str;
use std::str::FromStr;

use super::error;
use super::{Charset, RawLike};

/// Reads a single raw string when parsing a header.
pub fn from_one_raw_str<'a, R, T>(raw: &'a R) -> error::Result<T>
where
    R: RawLike<'a>,
    T: FromStr,
{
    if let Some(line) = raw.one()
        && !line.is_empty()
    {
        return from_raw_str(line);
    }
    Err(error::Error::Header)
}

/// Reads a raw string into a value.
pub fn from_raw_str<T: FromStr>(raw: &[u8]) -> error::Result<T> {
    let s = str::from_utf8(raw)?.trim();
    T::from_str(s).or(Err(error::Error::Header))
}

/// Reads a comma-delimited raw header into a Vec.
#[inline]
pub fn from_comma_delimited<'a, R, T>(raw: &'a R) -> error::Result<Vec<T>>
where
    R: RawLike<'a>,
    T: FromStr,
{
    let mut result = Vec::new();
    for s in raw.iter() {
        let s = str::from_utf8(s)?;
        result.extend(
            s.split(',')
                .filter_map(|x| match x.trim() {
                    "" => None,
                    y => Some(y),
                })
                .filter_map(|x| x.trim().parse().ok()),
        )
    }
    Ok(result)
}

/// Format an array into a comma-delimited string.
pub fn fmt_comma_delimited<T: Display>(f: &mut fmt::Formatter, parts: &[T]) -> fmt::Result {
    let mut iter = parts.iter();
    if let Some(part) = iter.next() {
        Display::fmt(part, f)?;
    }
    for part in iter {
        f.write_str(", ")?;
        Display::fmt(part, f)?;
    }
    Ok(())
}

/// An extended header parameter value (i.e., tagged with a character set and optionally,
/// a language), as defined in [RFC 5987](https://tools.ietf.org/html/rfc5987#section-3.2).
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct ExtendedValue {
    /// The character set that is used to encode the `value` to a string.
    pub charset: Charset,
    /// The human language details of the `value`, if available.
    pub language_tag: Option<LanguageTag>,
    /// The parameter value, as expressed in octets.
    pub value: Vec<u8>,
}

/// Parses extended header parameter values (`ext-value`), as defined in
/// [RFC 5987](https://tools.ietf.org/html/rfc5987#section-3.2).
///
/// Extended values are denoted by parameter names that end with `*`.
///
/// ## ABNF
///
/// ```text
/// ext-value     = charset  "'" [ language ] "'" value-chars
///               ; like RFC 2231's <extended-initial-value>
///               ; (see [RFC2231], Section 7)
///
/// charset       = "UTF-8" / "ISO-8859-1" / mime-charset
///
/// mime-charset  = 1*mime-charsetc
/// mime-charsetc = ALPHA / DIGIT
///               / "!" / "#" / "$" / "%" / "&"
///               / "+" / "-" / "^" / "_" / "`"
///               / "{" / "}" / "~"
///               ; as <mime-charset> in Section 2.3 of [RFC2978]
///               ; except that the single quote is not included
///               ; SHOULD be registered in the IANA charset registry
///
/// language      = <Language-Tag, defined in [RFC5646], Section 2.1>
///
/// value-chars   = *( pct-encoded / attr-char )
///
/// pct-encoded   = "%" HEXDIG HEXDIG
///               ; see [RFC3986], Section 2.1
///
/// attr-char     = ALPHA / DIGIT
///               / "!" / "#" / "$" / "&" / "+" / "-" / "."
///               / "^" / "_" / "`" / "|" / "~"
///               ; token except ( "*" / "'" / "%" )
/// ```
pub fn parse_extended_value(val: &str) -> error::Result<ExtendedValue> {
    // Break into three pieces separated by the single-quote character
    let mut parts = val.splitn(3, '\'');

    // Interpret the first piece as a Charset
    let charset: Charset = match parts.next() {
        None => return Err(error::Error::Header),
        Some(n) => FromStr::from_str(n)?,
    };

    // Interpret the second piece as a language tag
    let lang: Option<LanguageTag> = match parts.next() {
        None => return Err(error::Error::Header),
        Some("") => None,
        Some(s) => match s.parse() {
            Ok(lt) => Some(lt),
            Err(_) => return Err(error::Error::Header),
        },
    };

    // Interpret the third piece as a sequence of value characters
    let value: Vec<u8> = match parts.next() {
        None => return Err(error::Error::Header),
        Some(v) => percent_encoding::percent_decode(v.as_bytes()).collect(),
    };

    Ok(ExtendedValue { charset, language_tag: lang, value })
}

impl Display for ExtendedValue {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let encoded_value = percent_encoding::percent_encode(
            &self.value[..],
            percent_encoding_http::HTTP_VALUE,
        );
        if let Some(ref lang) = self.language_tag {
            write!(f, "{}'{}'{}", self.charset, lang, encoded_value)
        } else {
            write!(f, "{}''{}", self.charset, encoded_value)
        }
    }
}

/// Percent encode a sequence of bytes with a character set defined in
/// [https://tools.ietf.org/html/rfc5987#section-3.2][url]
///
/// [url]: https://tools.ietf.org/html/rfc5987#section-3.2
pub fn http_percent_encode(f: &mut fmt::Formatter, bytes: &[u8]) -> fmt::Result {
    let encoded = percent_encoding::percent_encode(bytes, percent_encoding_http::HTTP_VALUE);
    Display::fmt(&encoded, f)
}

mod percent_encoding_http {
    use percent_encoding::{AsciiSet, CONTROLS};

    // This encode set is used for HTTP header values and is defined at
    // https://tools.ietf.org/html/rfc5987#section-3.2
    pub const HTTP_VALUE: &AsciiSet = &CONTROLS
        .add(b' ')
        .add(b'"')
        .add(b'%')
        .add(b'\'')
        .add(b'(')
        .add(b')')
        .add(b'*')
        .add(b',')
        .add(b'/')
        .add(b':')
        .add(b';')
        .add(b'<')
        .add(b'-')
        .add(b'>')
        .add(b'?')
        .add(b'[')
        .add(b'\\')
        .add(b']')
        .add(b'{')
        .add(b'}');
}

#[cfg(test)]
mod tests {
    use super::{Charset, ExtendedValue, parse_extended_value};
    use language_tags::LanguageTag;

    #[test]
    fn test_parse_extended_value_with_encoding_and_language_tag() {
        let expected_language_tag = "en".parse::<LanguageTag>().unwrap();
        // RFC 5987, Section 3.2.2
        // Extended notation, using the Unicode character U+00A3 (POUND SIGN)
        let result = parse_extended_value("iso-8859-1'en'%A3%20rates");
        assert!(result.is_ok());
        let extended_value = result.unwrap();
        assert_eq!(Charset::Iso_8859_1, extended_value.charset);
        assert!(extended_value.language_tag.is_some());
        assert_eq!(expected_language_tag, extended_value.language_tag.unwrap());
        assert_eq!(vec![163, b' ', b'r', b'a', b't', b'e', b's'], extended_value.value);
    }

    #[test]
    fn test_parse_extended_value_with_encoding() {
        // RFC 5987, Section 3.2.2
        // Extended notation, using the Unicode characters U+00A3 (POUND SIGN)
        // and U+20AC (EURO SIGN)
        let result = parse_extended_value("UTF-8''%c2%a3%20and%20%e2%82%ac%20rates");
        assert!(result.is_ok());
        let extended_value = result.unwrap();
        assert_eq!(Charset::Ext("UTF-8".to_string()), extended_value.charset);
        assert!(extended_value.language_tag.is_none());
        assert_eq!(
            vec![
                194, 163, b' ', b'a', b'n', b'd', b' ', 226, 130, 172, b' ', b'r', b'a', b't',
                b'e', b's'
            ],
            extended_value.value
        );
    }

    #[test]
    fn test_parse_extended_value_missing_language_tag_and_encoding() {
        // From: https://greenbytes.de/tech/tc2231/#attwithfn2231quot2
        let result = parse_extended_value("foo%20bar.html");
        assert!(result.is_err());
    }

    #[test]
    fn test_parse_extended_value_partially_formatted() {
        let result = parse_extended_value("UTF-8'missing third part");
        assert!(result.is_err());
    }

    #[test]
    fn test_parse_extended_value_partially_formatted_blank() {
        let result = parse_extended_value("blank second part'");
        assert!(result.is_err());
    }

    #[test]
    fn test_fmt_extended_value_with_encoding_and_language_tag() {
        let extended_value = ExtendedValue {
            charset: Charset::Iso_8859_1,
            language_tag: Some("en".parse().expect("Could not parse language tag")),
            value: vec![163, b' ', b'r', b'a', b't', b'e', b's'],
        };
        assert_eq!("ISO-8859-1'en'%A3%20rates", format!("{}", extended_value));
    }

    #[test]
    fn test_fmt_extended_value_with_encoding() {
        let extended_value = ExtendedValue {
            charset: Charset::Ext("UTF-8".to_string()),
            language_tag: None,
            value: vec![
                194, 163, b' ', b'a', b'n', b'd', b' ', 226, 130, 172, b' ', b'r', b'a', b't',
                b'e', b's',
            ],
        };
        assert_eq!("UTF-8''%C2%A3%20and%20%E2%82%AC%20rates", format!("{}", extended_value));
    }
}