fn parse_param_content(content: &str) -> ParamContent {
    let mut tokens = content.split(';');
    // There must be at least one token produced by split, even if it's empty.
    let value = tokens.next().unwrap().trim();
    let mut map: BTreeMap<String, String> = tokens
        .filter_map(|kv| {
            kv.find('=').map(|idx| {
                let key = kv[0..idx].trim().to_lowercase();
                let mut value = kv[idx + 1..].trim();
                if value.starts_with('"') && value.ends_with('"') && value.len() > 1 {
                    value = &value[1..value.len() - 1];
                }
                (key, value.to_string())
            })
        })
        .collect();

    // Decode charset encoding, as described in RFC 2184, Section 4.
    let decode_key_list: Vec<String> = map
        .keys()
        .filter_map(|k| k.strip_suffix("*"))
        .map(String::from)
        // Skip encoded keys where there is already an equivalent decoded key in the map
        .filter(|k| !map.contains_key(k))
        .collect();
    let encodings = compute_parameter_encodings(&map, &decode_key_list);
    // Note that when we get here, we might still have entries in `encodings` for continuation segments
    // that didn't have a *0 segment at all. These shouldn't exist per spec so we can do whatever we want,
    // as long as we don't panic.
    for (k, (e, strip)) in encodings {
        if let Some(charset) = Charset::for_label_no_replacement(e.as_bytes()) {
            let key = format!("{}*", k);
            let percent_encoded_value = map.remove(&key).unwrap();
            let encoded_value = if strip {
                percent_decode(percent_encoded_value.splitn(3, '\'').nth(2).unwrap_or(""))
            } else {
                percent_decode(&percent_encoded_value)
            };
            let decoded_value = charset.decode_without_bom_handling(&encoded_value).0;
            map.insert(k, decoded_value.to_string());
        }
    }

    // Unwrap parameter value continuations, as described in RFC 2184, Section 3.
    let unwrap_key_list: Vec<String> = map
        .keys()
        .filter_map(|k| k.strip_suffix("*0"))
        .map(String::from)
        // Skip wrapped keys where there is already an unwrapped equivalent in the map
        .filter(|k| !map.contains_key(k))
        .collect();
    for unwrap_key in unwrap_key_list {
        let mut unwrapped_value = String::new();
        let mut index = 0;
        while let Some(wrapped_value_part) = map.remove(&format!("{}*{}", &unwrap_key, index)) {
            index = index + 1;
            unwrapped_value.push_str(&wrapped_value_part);
        }
        let old_value = map.insert(unwrap_key, unwrapped_value);
        assert!(old_value.is_none());
    }

    ParamContent {
        value: value.into(),
        params: map,
    }
}
/// Parse parameterized header values such as that for Content-Type
/// e.g. `multipart/alternative; boundary=foobar`
/// Note: this function is not made public as it may require
/// significant changes to be fully correct. For instance,
/// it does not handle quoted parameter values containing the
/// semicolon (';') character. It also produces a BTreeMap,
/// which implicitly does not support multiple parameters with
/// the same key. Also, the parameter values may contain language
/// information in a format specified by RFC 2184 which is thrown
/// away. The format for parameterized header values doesn't
/// appear to be strongly specified anywhere.
Parse parameterized header values such as that for Content-Type
e.g. `multipart/alternative; boundary=foobar`
Note: this function is not made public as it may require
significant changes to be fully correct. For instance,
it does not handle quoted parameter values containing the
semicolon (';') character. It also produces a BTreeMap,
which implicitly does not support multiple parameters with
the same key. Also, the parameter values may contain language
information in a format specified by RFC 2184 which is thrown
away. The format for parameterized header values doesn't
appear to be strongly specified anywhere.
Parse parameterized header values such as that for Content - Type e . g . ` multipart / alternative ; boundary = foobar ` Note : this function is not made public as it may require significant changes to be fully correct . For instance it does not handle quoted parameter values containing the semicolon ( ' ; ' ) character . It also produces a BTreeMap which implicitly does not support multiple parameters with the same key . Also the parameter values may contain language information in a format specified by RFC 2184 which is thrown away . The format for parameterized header values doesn ' t appear to be strongly specified anywhere .
fn parse_param_content(content: &str) -> ParamContent {
    let mut tokens = content.split(';');
    // There must be at least one token produced by split, even if it's empty.
    let value = tokens.next().unwrap().trim();
    let mut map: BTreeMap<String, String> = tokens
        .filter_map(|kv| {
            kv.find('=').map(|idx| {
                let key = kv[0..idx].trim().to_lowercase();
                let mut value = kv[idx + 1..].trim();
                if value.starts_with('"') && value.ends_with('"') && value.len() > 1 {
                    value = &value[1..value.len() - 1];
                }
                (key, value.to_string())
            })
        })
        .collect();
    // Decode charset encoding, as described in RFC 2184, Section 4.
    let decode_key_list: Vec<String> = map
        .keys()
        .filter_map(|k| k.strip_suffix("*"))
        .map(String::from)
        // Skip encoded keys where there is already an equivalent decoded key in the map
        .filter(|k| !map.contains_key(k))
        .collect();
    let encodings = compute_parameter_encodings(&map, &decode_key_list);
    // Note that when we get here, we might still have entries in `encodings` for continuation segments
    // that didn't have a *0 segment at all. These shouldn't exist per spec so we can do whatever we want,
    // as long as we don't panic.
    for (k, (e, strip)) in encodings {
        if let Some(charset) = Charset::for_label_no_replacement(e.as_bytes()) {
            let key = format!("{}*", k);
            let percent_encoded_value = map.remove(&key).unwrap();
            let encoded_value = if strip {
                percent_decode(percent_encoded_value.splitn(3, '\'').nth(2).unwrap_or(""))
            } else {
                percent_decode(&percent_encoded_value)
            };
            let decoded_value = charset.decode_without_bom_handling(&encoded_value).0;
            map.insert(k, decoded_value.to_string());
        }
    }
    // Unwrap parameter value continuations, as described in RFC 2184, Section 3.
    let unwrap_key_list: Vec<String> = map
        .keys()
        .filter_map(|k| k.strip_suffix("*0"))
        .map(String::from)
        // Skip wrapped keys where there is already an unwrapped equivalent in the map
        .filter(|k| !map.contains_key(k))
        .collect();
    for unwrap_key in unwrap_key_list {
        let mut unwrapped_value = String::new();
        let mut index = 0;
        while let Some(wrapped_value_part) = map.remove(&format!("{}*{}", &unwrap_key, index)) {
            index = index + 1;
            unwrapped_value.push_str(&wrapped_value_part);
        }
        let old_value = map.insert(unwrap_key, unwrapped_value);
        assert!(old_value.is_none());
    }
    ParamContent {
        value: value.into(),
        params: map,
    }
}
fn parse_param_content ( content : & str ) -> ParamContent { let mut tokens = content . split ( ';' ) ; // There must be at least one token produced by split, even if it's empty. let value = tokens . next ( ) . unwrap ( ) . trim ( ) ; let mut map : BTreeMap < String , String > = tokens . filter_map ( | kv | { kv . find ( '=' ) . map ( | idx | { let key = kv [ 0 .. idx ] . trim ( ) . to_lowercase ( ) ; let mut value = kv [ idx + 1 .. ] . trim ( ) ; if value . starts_with ( '"' ) && value . ends_with ( '"' ) && value . len ( ) > 1 { value = & value [ 1 .. value . len ( ) - 1 ] ; } ( key , value . to_string ( ) ) } ) } ) . collect ( ) ; // Decode charset encoding, as described in RFC 2184, Section 4. let decode_key_list : Vec < String > = map . keys ( ) . filter_map ( | k | k . strip_suffix ( " " ) ) . map ( String :: from ) // Skip encoded keys where there is already an equivalent decoded key in the map . filter ( | k | ! map . contains_key ( k ) ) . collect ( ) ; let encodings = compute_parameter_encodings ( & map , & decode_key_list ) ; // Note that when we get here, we might still have entries in `encodings` for continuation segments // that didn't have a *0 segment at all. These shouldn't exist per spec so we can do whatever we want, // as long as we don't panic. for ( k , ( e , strip ) ) in encodings { if let Some ( charset ) = Charset :: for_label_no_replacement ( e . as_bytes ( ) ) { let key = format ! ( " " k ) ; let percent_encoded_value = map . remove ( & key ) . unwrap ( ) ; let encoded_value = if strip { percent_decode ( percent_encoded_value . splitn ( 3 , '\'' ) . nth ( 2 ) . unwrap_or ( " " ) ) } else { percent_decode ( & percent_encoded_value ) } ; let decoded_value = charset . decode_without_bom_handling ( & encoded_value ) . 0 ; map . insert ( k , decoded_value . to_string ( ) ) ; } } // Unwrap parameter value continuations, as described in RFC 2184, Section 3. let unwrap_key_list : Vec < String > = map . keys ( ) . filter_map ( | k | k . strip_suffix ( " " ) ) . map ( String :: from ) // Skip wrapped keys where there is already an unwrapped equivalent in the map . filter ( | k | ! map . contains_key ( k ) ) . collect ( ) ; for unwrap_key in unwrap_key_list { let mut unwrapped_value = String :: new ( ) ; let mut index = 0 ; while let Some ( wrapped_value_part ) = map . remove ( & format ! ( " " unwrap_key index ) ) { index = index + 1 ; unwrapped_value . push_str ( & wrapped_value_part ) ; } let old_value = map . insert ( unwrap_key , unwrapped_value ) ; assert ! ( old_value is_none ( ) ) ; } ParamContent { value : value . into ( ) , params : map , } }
Parse parameterized header values such as that for Content-Type
e.g.
Parse parameterized header values such as that for Content - Type e . g .
content
&str
content
&str