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// Copyright 2023 宋昊文
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use std::sync::Arc;
use crate::internet::body::Body;
use crate::internet::header;
use crate::internet::header::{Header, HeaderSearch};
use crate::internet::header_field::AsHeaderField;
use crate::internet::headers::content_type::AsContentType;
use crate::internet::syntax;
use crate::util::raw_string::{StrEq, ToInt};
use super::sip_message::{SipFirstLine, SipMessage};
enum ParsingState {
Empty,
ReadingFirstLine,
ReadingHeaders(Option<SipFirstLine>, Option<Vec<Header>>, Option<Vec<u8>>),
ExpectingBody(Option<SipFirstLine>, Option<Vec<Header>>, usize),
}
pub struct SipParser {
buffer: Vec<u8>,
p: usize,
state: ParsingState,
}
impl SipParser {
pub fn new() -> SipParser {
SipParser {
buffer: Vec::new(),
p: 0,
state: ParsingState::Empty,
}
}
pub fn feed(&mut self, data: &[u8]) {
self.buffer.extend_from_slice(data);
}
pub fn produce(&mut self) -> Result<Option<SipMessage>, &str> {
'outer: loop {
match &mut self.state {
ParsingState::Empty => {
if self.p < self.buffer.len() {
let c1 = self.buffer[self.p];
if c1 == b'\r' {
if self.p + 1 < self.buffer.len() {
let c2 = self.buffer[self.p + 1];
if c2 == b'\n' {
if self.p + 3 < self.buffer.len() {
let c3 = self.buffer[self.p + 2];
let c4 = self.buffer[self.p + 3];
if c3 == b'\r' && c4 == b'\n' {
self.p = self.p + 4;
return Ok(Some(SipMessage::Ping));
}
}
self.p = self.p + 2;
return Ok(Some(SipMessage::Pong));
} else {
return Err("dangling Carriage Return\n");
}
} else {
return Ok(None);
}
}
self.state = ParsingState::ReadingFirstLine;
} else {
return Ok(None);
}
}
ParsingState::ReadingFirstLine => {
let buf = &self.buffer[self.p..];
if let Ok(o) = SipFirstLine::decode_first_line(buf) {
match o {
Some((first_line, consumed)) => {
self.p = self.p + consumed;
self.state = ParsingState::ReadingHeaders(
Some(first_line),
Some(Vec::new()),
Some(Vec::new()),
);
}
None => return Ok(None),
}
} else {
return Err("error decoding first line");
}
}
ParsingState::ReadingHeaders(first_line, message_headers, line) => {
let mut first_fold: Option<usize> = None;
let mut last_fold: usize = 0;
'inner: loop {
let chunk = &self.buffer[self.p + last_fold..];
let mut iter = chunk.iter();
if let Some(position) = iter.position(|c| *c == b'\r') {
if let Some(c) = iter.next() {
if *c == b'\n' {
if last_fold + position == 0 {
self.p = self.p + 2;
let mut content_length: Option<usize> = None;
if let Some(headers) = message_headers {
if let Some(content_length_header) =
header::search(headers, b"Content-Length", true)
{
if let Ok(i) =
content_length_header.get_value().to_int()
{
content_length = Some(i);
}
}
}
if let Some(content_length) = content_length {
self.state = ParsingState::ExpectingBody(
first_line.take(),
message_headers.take(),
content_length,
);
continue 'outer;
} else {
return Err("require explicit content-length");
}
}
if let Some(c) = iter.next() {
if *c == b'\t' {
if first_fold.is_none() {
first_fold = Some(position);
}
last_fold = last_fold + position + 3;
if let Some(line) = line {
line.extend_from_slice(&chunk[..position]);
line.push(b' ');
} else {
panic!("line value missing for no obvious reason")
}
continue 'inner;
}
}
if let Some(mut line) = line.take() {
line.extend_from_slice(&chunk[..position]);
let mut iter = line.iter();
if let Some(idx) = iter.position(|c| *c == b':') {
if let Some(first_fold) = first_fold {
if first_fold < idx {
return Err("obsolete line foldings are not allowed in header names");
}
}
match message_headers {
Some(headers) => {
headers.push(Header::new(
syntax::trim(&line[..idx]).to_vec(),
syntax::trim(&line[idx + 1..]).to_vec(),
));
self.p = self.p + last_fold + position + 2;
self.state = ParsingState::ReadingHeaders(
first_line.take(),
message_headers.take(),
Some(Vec::new()),
);
continue 'outer;
}
None => {
panic!("message_headers value missing for no obvious reason")
}
}
} else {
return Err("require header name");
}
} else {
panic!("line value missing for no obvious reason")
}
} else {
return Err("dangling Carriage Return");
}
}
}
return Ok(None);
}
}
ParsingState::ExpectingBody(first_line, message_headers, content_length) => {
if self.p + *content_length <= self.buffer.len() {
if let Some(headers) = message_headers {
let mut construct_flag: Option<i32> = None;
let mut boundary: Option<Vec<u8>> = None;
for header in HeaderSearch::new(headers, b"Content-Type", true) {
let field = header.get_value().as_header_field();
if let Some(content_type) = field.as_content_type() {
if content_type.major_type.equals_bytes(b"message", true) {
construct_flag = Some(1);
} else if content_type
.major_type
.equals_bytes(b"multipart", true)
{
construct_flag = Some(2);
boundary = Some(content_type.boundary.to_vec());
} else {
construct_flag = Some(0);
}
}
}
if *content_length == 0 {
let ok = Ok(Some(SipMessage::new(
first_line.take().unwrap(),
message_headers.take(),
None,
)));
self.buffer = self.buffer.split_off(self.p);
self.p = 0;
self.state = ParsingState::Empty;
return ok;
}
match construct_flag {
Some(flag) => match flag {
0 => {
let body = Body::construct_raw(
&self.buffer[self.p..self.p + *content_length],
);
let ok = Ok(Some(SipMessage::new(
first_line.take().unwrap(),
message_headers.take(),
Some(Arc::new(body)),
)));
self.buffer =
self.buffer.split_off(self.p + *content_length);
self.p = 0;
self.state = ParsingState::Empty;
return ok;
}
1 => match Body::construct_message(
&self.buffer[self.p..self.p + *content_length],
) {
Ok(body) => {
let ok = Ok(Some(SipMessage::new(
first_line.take().unwrap(),
message_headers.take(),
Some(Arc::new(body)),
)));
self.buffer =
self.buffer.split_off(self.p + *content_length);
self.p = 0;
self.state = ParsingState::Empty;
return ok;
}
Err(e) => {
return Err(e);
}
},
2 => {
if let Some(boundary) = boundary {
match Body::construct_multipart(
&self.buffer[self.p..self.p + *content_length],
&boundary,
) {
Ok(body) => {
let ok = Ok(Some(SipMessage::new(
first_line.take().unwrap(),
message_headers.take(),
Some(Arc::new(body)),
)));
self.buffer = self
.buffer
.split_off(self.p + *content_length);
self.p = 0;
self.state = ParsingState::Empty;
return ok;
}
Err(e) => {
return Err(e);
}
}
} else {
return Err("missing multipart boundary");
}
}
_ => {
panic!("impossible condition")
}
},
None => {
panic!("require explicit content-type")
}
}
}
return Err("seriously?");
} else {
return Ok(None);
}
}
}
}
}
}