rust-imap/src/types/capabilities.rs
2021-07-05 20:11:36 -04:00

117 lines
4.5 KiB
Rust

use crate::error::{Error, ParseError};
use crate::parse::try_handle_unilateral;
use crate::types::UnsolicitedResponse;
use imap_proto::{Capability, Response};
use ouroboros::self_referencing;
use std::collections::hash_set::Iter;
use std::collections::HashSet;
use std::sync::mpsc;
const IMAP4REV1_CAPABILITY: &str = "IMAP4rev1";
const AUTH_CAPABILITY_PREFIX: &str = "AUTH=";
/// From [section 7.2.1 of RFC 3501](https://tools.ietf.org/html/rfc3501#section-7.2.1).
///
/// A list of capabilities that the server supports.
/// The capability list will include the atom "IMAP4rev1".
///
/// In addition, all servers implement the `STARTTLS`, `LOGINDISABLED`, and `AUTH=PLAIN` (described
/// in [IMAP-TLS](https://tools.ietf.org/html/rfc2595)) capabilities. See the [Security
/// Considerations section of the RFC](https://tools.ietf.org/html/rfc3501#section-11) for
/// important information.
///
/// A capability name which begins with `AUTH=` indicates that the server supports that particular
/// authentication mechanism.
///
/// The `LOGINDISABLED` capability indicates that the `LOGIN` command is disabled, and that the
/// server will respond with a [`super::Error::No`] response to any attempt to use the `LOGIN`
/// command even if the user name and password are valid. An IMAP client MUST NOT issue the
/// `LOGIN` command if the server advertises the `LOGINDISABLED` capability.
///
/// Other capability names indicate that the server supports an extension, revision, or amendment
/// to the IMAP4rev1 protocol. Capability names either begin with `X` or they are standard or
/// standards-track [RFC 3501](https://tools.ietf.org/html/rfc3501) extensions, revisions, or
/// amendments registered with IANA.
///
/// Client implementations SHOULD NOT require any capability name other than `IMAP4rev1`, and MUST
/// ignore any unknown capability names.
#[self_referencing]
pub struct Capabilities {
data: Vec<u8>,
#[borrows(data)]
#[covariant]
pub(crate) capabilities: HashSet<Capability<'this>>,
}
impl Capabilities {
/// Parse the given input into one or more [`Capabilitity`] responses.
pub fn parse(
owned: Vec<u8>,
unsolicited: &mut mpsc::Sender<UnsolicitedResponse>,
) -> Result<Self, Error> {
CapabilitiesTryBuilder {
data: owned,
capabilities_builder: |input| {
let mut lines = input;
let mut caps = HashSet::new();
loop {
match imap_proto::parser::parse_response(lines) {
Ok((rest, Response::Capabilities(c))) => {
lines = rest;
caps.extend(c);
}
Ok((rest, data)) => {
lines = rest;
if let Some(resp) = try_handle_unilateral(data, unsolicited) {
break Err(resp.into());
}
}
_ => {
break Err(Error::Parse(ParseError::Invalid(lines.to_vec())));
}
}
if lines.is_empty() {
break Ok(caps);
}
}
},
}
.try_build()
}
/// Check if the server has the given capability.
pub fn has<'a>(&self, cap: &Capability<'a>) -> bool {
self.borrow_capabilities().contains(cap)
}
/// Check if the server has the given capability via str.
pub fn has_str<S: AsRef<str>>(&self, cap: S) -> bool {
let s = cap.as_ref();
if s.eq_ignore_ascii_case(IMAP4REV1_CAPABILITY) {
return self.has(&Capability::Imap4rev1);
}
if s.len() > AUTH_CAPABILITY_PREFIX.len() {
let (pre, val) = s.split_at(AUTH_CAPABILITY_PREFIX.len());
if pre.eq_ignore_ascii_case(AUTH_CAPABILITY_PREFIX) {
return self.has(&Capability::Auth(val.into()));
}
}
self.has(&Capability::Atom(s.into()))
}
/// Iterate over all the server's capabilities
pub fn iter(&self) -> Iter<'_, Capability<'_>> {
self.borrow_capabilities().iter()
}
/// Returns how many capabilities the server has.
pub fn len(&self) -> usize {
self.borrow_capabilities().len()
}
/// Returns true if the server purports to have no capabilities.
pub fn is_empty(&self) -> bool {
self.borrow_capabilities().is_empty()
}
}