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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 crate::internet::header;
use crate::internet::header::Header;
use crate::internet::headers::byte_range;
use crate::internet::syntax;
use crate::util::raw_string::{StrFind, ToInt};
use super::msrp_chunk::ContinuationFlag;
use super::msrp_chunk::MsrpChunk;
use super::msrp_chunk::MsrpRequestLine;
use super::msrp_chunk::MsrpResponseLine;
enum MsrpFirstLine {
Request(MsrpRequestLine),
Response(MsrpResponseLine),
}
impl MsrpFirstLine {
fn transaction_id(&self) -> &Vec<u8> {
match self {
MsrpFirstLine::Request(req_line) => &req_line.transaction_id,
MsrpFirstLine::Response(resp_line) => &resp_line.transaction_id,
}
}
}
fn new_msrp_chunk(
first_line: MsrpFirstLine,
headers: Vec<Header>,
body: Option<Vec<u8>>,
continuation_flag: ContinuationFlag,
) -> MsrpChunk {
match first_line {
MsrpFirstLine::Request(req_line) => {
MsrpChunk::new_request_chunk(req_line, headers, body, continuation_flag)
}
MsrpFirstLine::Response(resp_line) => MsrpChunk::new_response_chunk(resp_line, headers),
}
}
enum ParsingState {
ReadingFirstLine,
ReadingHeaders(Option<MsrpFirstLine>, Option<Vec<Header>>),
ReadingBody(
Option<MsrpRequestLine>,
Option<Vec<Header>>,
Option<usize>,
usize,
),
}
pub struct MsrpParser {
buffer: Vec<u8>,
p: usize,
state: ParsingState,
}
impl MsrpParser {
pub fn new() -> MsrpParser {
MsrpParser {
buffer: Vec::new(),
p: 0,
state: ParsingState::ReadingFirstLine,
}
}
pub fn feed(&mut self, data: &[u8]) {
self.buffer.extend_from_slice(data);
}
pub fn produce(&mut self) -> Result<Option<MsrpChunk>, &str> {
'outer: loop {
match &mut self.state {
ParsingState::ReadingFirstLine => {
let mut i = 0;
while self.p + i < self.buffer.len() {
let b1 = self.buffer[self.p + i];
if b1 == b'\r' {
if self.p + i + 1 < self.buffer.len() {
let b2 = self.buffer[self.p + i + 1];
if b2 == b'\n' {
let mut iter =
self.buffer[self.p..self.p + i].splitn(3, |c| *c == b' ');
if let Some(s1) = iter.next() {
if s1 == b"MSRP" {
if let Some(s2) = iter.next() {
if let Some(s3) = iter.next() {
let s4;
let s5;
if let Some(idx) =
s3.iter().position(|c| *c == b' ')
{
s4 = &s3[..idx];
s5 = Some(s3[idx + 1..].to_vec());
} else {
s4 = s3;
s5 = None;
}
if s4.len() == 3
&& s4[0] >= b'0'
&& s4[0] <= b'9'
&& s4[1] >= b'0'
&& s4[1] <= b'9'
&& s4[2] >= b'0'
&& s4[2] <= b'9'
{
if let Ok(status_code) = s4.to_int() {
let resp_line = MsrpResponseLine {
transaction_id: s2.to_vec(),
status_code,
comment: s5,
};
self.state =
ParsingState::ReadingHeaders(
Some(MsrpFirstLine::Response(
resp_line,
)),
Some(Vec::new()),
);
self.p = self.p + i + 2;
continue 'outer;
}
} else {
if let None = s5 {
let req_line = MsrpRequestLine {
transaction_id: s2.to_vec(),
request_method: s4.to_vec(),
};
self.state =
ParsingState::ReadingHeaders(
Some(MsrpFirstLine::Request(
req_line,
)),
Some(Vec::new()),
);
self.p = self.p + i + 2;
continue 'outer;
}
}
}
}
}
}
return Err("Bad format");
}
}
}
i = i + 1;
}
}
ParsingState::ReadingHeaders(first_line, headers) => {
let mut i = 0;
while self.p + i < self.buffer.len() {
let b1 = self.buffer[self.p + i];
if b1 == b'\r' {
if self.p + i + 1 < self.buffer.len() {
let b2 = self.buffer[self.p + i + 1];
if b2 == b'\n' {
if let Some(first_line_) = first_line {
let transaction_id = first_line_.transaction_id();
if let Some(idx) =
self.buffer[self.p..self.p + i].index_of(b"-------")
{
if idx + 7 + transaction_id.len() == i {
if &self.buffer[self.p + idx + 7..self.p + i]
== transaction_id
{
self.buffer =
self.buffer.split_off(self.p + i + 2);
self.p = 0;
let ok = Ok(Some(new_msrp_chunk(
first_line.take().unwrap(),
headers.take().unwrap(),
None,
ContinuationFlag::Complete,
)));
self.state = ParsingState::ReadingFirstLine;
return ok;
}
}
}
if i == 0 {
if let Some(first_line) = first_line.take() {
match first_line {
MsrpFirstLine::Request(req_line) => {
if let Some(headers) = headers.take() {
if let Some(byte_range_header) = header::search(&headers, b"Byte-Range", false) {
let byte_range_header_value = byte_range_header.get_value();
if let Some(byte_range) = byte_range::parse(byte_range_header_value) {
if let Some(to) = byte_range.to {
self.state = ParsingState::ReadingBody(Some(req_line), Some(headers), Some(to + 1 - byte_range.from), byte_range.total + 1 - byte_range.from);
self.p = self.p + 2;
continue 'outer;
} else {
self.state = ParsingState::ReadingBody(Some(req_line), Some(headers), None, byte_range.total + 1 - byte_range.from);
self.p = self.p + 2;
continue 'outer;
}
}
}
self.state = ParsingState::ReadingBody(Some(req_line), Some(headers), None, 0);
self.p = self.p + 2;
continue 'outer;
} else {
return Err("impossible condition");
}
}
MsrpFirstLine::Response(_) => {
return Err("MSRP Responses are not allowed to have body")
}
}
} else {
return Err("impossible condition");
}
} else {
let line = &self.buffer[self.p..self.p + i];
if let Some(idx) = line.iter().position(|c| *c == b':')
{
match headers {
Some(headers) => {
headers.push(Header::new(
syntax::trim(&line[..idx]).to_vec(),
syntax::trim(&line[idx + 1..]).to_vec(),
));
self.p = self.p + i + 2;
continue 'outer;
}
_ => {
return Err("impossible condition");
}
}
} else {
return Err("Bad format");
}
}
} else {
return Err("impossible condition");
}
}
}
}
i = i + 1;
}
}
ParsingState::ReadingBody(req_line, headers, content_length, range_limit) => {
if let Some(req_line_) = req_line {
if let Some(content_length) = content_length {
let mut boundary = b"\r\n-------".to_vec();
boundary.extend(&req_line_.transaction_id);
boundary.extend(b"\r\n");
if self.buffer[self.p + *content_length..].start_with(&boundary) {
let data = self.buffer[self.p..self.p + *content_length].to_vec();
self.buffer = self
.buffer
.split_off(self.p + *content_length + boundary.len());
self.p = 0;
return Ok(Some(MsrpChunk::new_request_chunk(
req_line.take().unwrap(),
headers.take().unwrap(),
Some(data),
ContinuationFlag::Complete,
)));
}
if self.p + *content_length + boundary.len() <= self.buffer.len() {
return Err("Missing closing boundary");
} else {
return Ok(None);
}
} else {
let mut continuation_flag = None;
if let Some(idx) = self.buffer[self.p..].index_of(b"\r\n-------") {
if self.buffer[self.p + idx + 9..]
.start_with(&req_line_.transaction_id)
{
if self.buffer
[self.p + idx + 9 + req_line_.transaction_id.len()..]
.start_with(b"$\r\n")
{
continuation_flag = Some((idx, ContinuationFlag::Complete));
} else if self.buffer
[self.p + idx + 9 + req_line_.transaction_id.len()..]
.start_with(b"#\r\n")
{
continuation_flag = Some((idx, ContinuationFlag::Abort));
} else if self.buffer
[self.p + idx + 9 + req_line_.transaction_id.len()..]
.start_with(b"+\r\n")
{
continuation_flag =
Some((idx, ContinuationFlag::Continuation));
}
}
}
if let Some((idx, continuation_flag)) = continuation_flag {
if idx < *range_limit {
let data = self.buffer[self.p..self.p + idx].to_vec();
self.buffer = self.buffer.split_off(
self.p + idx + 9 + req_line_.transaction_id.len() + 3,
);
self.p = 0;
let ok = Ok(Some(MsrpChunk::new_request_chunk(
req_line.take().unwrap(),
headers.take().unwrap(),
Some(data),
continuation_flag,
)));
self.state = ParsingState::ReadingFirstLine;
return ok;
} else {
return Err("More data than declared");
}
} else {
if self.p + *range_limit + 9 + req_line_.transaction_id.len() + 3
<= self.buffer.len()
{
return Err("Missing closing boundary");
}
return Ok(None);
}
}
} else {
return Err("impossible condition");
}
}
}
}
}
}