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use std::boxed::Box;
use std::convert::TryInto;
use std::iter::Peekable;
use crate::composed::message::Message;
use crate::composed::Deserializable;
use crate::errors::Result;
use crate::packet::Packet;
use crate::types::Tag;
pub struct MessageParser<I: Sized + Iterator<Item = Packet>> {
source: Peekable<I>,
}
fn next<I: Iterator<Item = Packet>>(packets: &mut Peekable<I>) -> Option<Result<Message>> {
while let Some(packet) = packets.by_ref().next() {
// for packet in packets.by_ref() {
debug!("{:?}: ", packet);
let tag = packet.tag();
match tag {
Tag::LiteralData => {
return match packet.try_into() {
Ok(data) => Some(Ok(Message::Literal(data))),
Err(err) => Some(Err(err)),
};
}
Tag::CompressedData => {
return match packet.try_into() {
Ok(data) => Some(Ok(Message::Compressed(data))),
Err(err) => Some(Err(err)),
};
}
// ESK :- Public-Key Encrypted Session Key Packet |
// Symmetric-Key Encrypted Session Key Packet.
Tag::PublicKeyEncryptedSessionKey | Tag::SymKeyEncryptedSessionKey => {
return match packet.try_into() {
Ok(p) => {
let mut esk = vec![p];
let mut edata = Vec::new();
// while ESK take em
while packets.peek().map(|p| {
p.tag() == Tag::PublicKeyEncryptedSessionKey
|| p.tag() == Tag::SymKeyEncryptedSessionKey
}) == Some(true)
{
esk.push(packets.next().expect("peeked").try_into().expect("peeked"));
}
// while edata take em
while packets.peek().map(|p| {
p.tag() == Tag::SymEncryptedData
|| p.tag() == Tag::SymEncryptedProtectedData
}) == Some(true)
{
edata.push(packets.next().expect("peeked").try_into().expect("peeked"));
}
Some(Ok(Message::Encrypted { esk, edata }))
}
Err(err) => Some(Err(err)),
};
}
// Encrypted Data :- Symmetrically Encrypted Data Packet |
// Symmetrically Encrypted Integrity Protected Data Packet
Tag::SymEncryptedData | Tag::SymEncryptedProtectedData => {
return match packet.try_into() {
Ok(p) => {
let esk = Vec::new();
let mut edata = vec![p];
// while edata take em
while packets.peek().map(|p| {
p.tag() == Tag::SymEncryptedData
|| p.tag() == Tag::SymEncryptedProtectedData
}) == Some(true)
{
edata.push(packets.next().expect("peeked").try_into().expect("peeked"));
}
Some(Ok(Message::Encrypted { esk, edata }))
}
Err(err) => Some(Err(err)),
};
}
Tag::Signature => {
return match packet.try_into() {
Ok(signature) => {
let m = next(packets.by_ref());
let message = if let Some(Err(err)) = m {
return Some(Err(err));
} else {
m.map(|m| Box::new(m.expect("already checked")))
};
Some(Ok(Message::Signed {
message,
one_pass_signature: None,
signature,
}))
}
Err(err) => Some(Err(err)),
};
}
Tag::OnePassSignature => {
return match packet.try_into() {
Ok(p) => {
let one_pass_signature = Some(p);
let m = next(packets.by_ref());
let message = if let Some(Err(err)) = m {
return Some(Err(err));
} else {
m.map(|m| Box::new(m.expect("already checked")))
};
let signature =
if packets.peek().map(|p| p.tag() == Tag::Signature) == Some(true) {
packets.next().expect("peeked").try_into().expect("peeked")
} else {
return Some(Err(format_err!(
"missing signature for, one pass signature"
)));
};
Some(Ok(Message::Signed {
message,
one_pass_signature,
signature,
}))
}
Err(err) => Some(Err(err)),
};
}
Tag::Marker => {
// Marker Packets are ignored
// see https://tools.ietf.org/html/rfc4880#section-5.8
}
_ => {
return Some(Err(format_err!("unexpected packet {:?}", packet.tag())));
}
}
}
None
}
impl<I: Sized + Iterator<Item = Packet>> Iterator for MessageParser<I> {
type Item = Result<Message>;
fn next(&mut self) -> Option<Self::Item> {
next(self.source.by_ref())
}
}
impl Deserializable for Message {
/// Parse a composed message.
/// Ref: https://tools.ietf.org/html/rfc4880#section-11.3
fn from_packets<'a, I: Iterator<Item = Packet> + 'a>(
packets: std::iter::Peekable<I>,
) -> Box<dyn Iterator<Item = Result<Self>> + 'a> {
Box::new(MessageParser {
source: packets.peekable(),
})
}
}