Enum HeaderForm 

#[non_exhaustive]
pub enum HeaderForm {
    Raw,
    Text,
    Addresses,
    GroupedAddresses,
    MessageIds,
    Date,
    URLs,
}

Selector for the RFC 8621 parsed-form of a header value.

This is the form-token from a JMAP header:<name>:as<form> property selector, normalised to an enum.

Display emits the canonical JMAP form-token string (asRaw, asAddresses, …, asURLs). FromStr accepts exactly that set of strings; any other input yields UnknownHeaderForm.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Raw

Trim surrounding whitespace; return the bytes as a UTF-8 string. (§4.1.2.1)

Non-UTF-8 bytes — legal in raw RFC 5322 but not in JMAP wire format — are replaced with U+FFFD REPLACEMENT CHARACTER (lossy conversion). This preserves the position and rough shape of malformed input so callers can flag a mojibake header without losing the rest of the field body.

Text

RFC 8621 §4.1.2.2 Text form. Unfold whitespace, strip the trailing CRLF and leading SP, decode all syntactically-correct RFC 2047 encoded-words, then Unicode-normalise the result to NFC.

This is the form most commonly used by JMAP clients fetching human-readable header fields like Subject, Comments, Keywords, and List-Id.

Addresses

Parse as an RFC 5322 address-list. Group structure is discarded; only the flat list of mailboxes is returned. (§4.1.2.3)

GroupedAddresses

Parse as an RFC 5322 address-list, preserving group structure. (§4.1.2.4)

MessageIds

Parse as a list of RFC 5322 msg-id values. Surrounding angle brackets and CFWS are stripped. (§4.1.2.5)

Date

Parse as an RFC 5322 §3.3 date-time. (§4.1.2.6)

URLs

Parse as an RFC 2369 list of URLs. Surrounding angle brackets and comments are stripped. (§4.1.2.7)

Implementations

impl HeaderForm

pub fn as_jmap_token(&self) -> &'static str

Return the canonical RFC 8621 §4.1.2 form-token string for this variant.

The token starts with as (the convention used in JMAP property selectors such as header:Subject:asText). Inverse of HeaderForm’s FromStr impl.

Trait Implementations

impl Clone for HeaderForm

fn clone(&self) -> HeaderForm

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HeaderForm

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for HeaderForm

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for HeaderForm

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for HeaderForm

impl FromStr for HeaderForm

type Err = UnknownHeaderForm

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl Hash for HeaderForm

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for HeaderForm

fn eq(&self, other: &HeaderForm) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for HeaderForm

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for HeaderForm