From 9f8232f7f1577b30ef42f4528c1570e847b60e00 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rodolphe=20Br=C3=A9ard?= <rodolphe@what.tf>
Date: Sun, 19 Mar 2023 19:06:29 +0100
Subject: [PATCH] Read entries

---
 Cargo.toml       |  1 +
 src/entry.rs     | 82 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/handshake.rs |  4 ++-
 src/main.rs      | 33 +++++++++++++++++++
 4 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 src/entry.rs

diff --git a/Cargo.toml b/Cargo.toml
index e433ea2..584c1df 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,3 +8,4 @@ license = "MIT OR Apache-2.0"
 publish = false
 
 [dependencies]
+nom = "^7.1"
diff --git a/src/entry.rs b/src/entry.rs
new file mode 100644
index 0000000..81ca0fc
--- /dev/null
+++ b/src/entry.rs
@@ -0,0 +1,82 @@
+use nom::bytes::streaming::{tag, take_till1, take_while1};
+use nom::IResult;
+
+#[derive(Debug)]
+pub struct Entry {
+	session_id: String,
+	token: String,
+	data: Vec<u8>,
+}
+
+impl Entry {
+	pub fn get_session_id(&self) -> &str {
+		&self.session_id
+	}
+
+	pub fn get_token(&self) -> &str {
+		&self.token
+	}
+
+	pub fn get_data(&self) -> &[u8] {
+		&self.data
+	}
+
+	pub fn is_end_of_message(&self) -> bool {
+		self.data == vec![b'.']
+	}
+
+	pub fn from_bytes(input: &[u8]) -> Result<Entry, String> {
+		let (_, entry) = parse_entry(input).map_err(|e| format!("parsing error: {e}"))?;
+		Ok(entry)
+	}
+}
+
+fn is_eol(c: u8) -> bool {
+	c == b'\n'
+}
+
+fn is_body_char(c: u8) -> bool {
+	!(c as char).is_control()
+}
+
+fn is_parameter_char(c: u8) -> bool {
+	is_body_char(c) && (c as char) != '|'
+}
+
+fn parse_string_parameter(input: &[u8]) -> IResult<&[u8], String> {
+	let (input, s) = take_while1(is_parameter_char)(input)?;
+	Ok((input, String::from_utf8(s.to_vec()).unwrap()))
+}
+
+fn parse_delimiter(input: &[u8]) -> IResult<&[u8], &[u8]> {
+	tag("|")(input)
+}
+
+fn parse_data(input: &[u8]) -> IResult<&[u8], Vec<u8>> {
+	let (input, s) = take_till1(is_eol)(input)?;
+	Ok((input, s.to_vec()))
+}
+
+fn parse_entry(input: &[u8]) -> IResult<&[u8], Entry> {
+	let (input, _type) = tag("filter")(input)?;
+	let (input, _) = parse_delimiter(input)?;
+	let (input, _version) = parse_string_parameter(input)?;
+	let (input, _) = parse_delimiter(input)?;
+	let (input, _timestamp) = parse_string_parameter(input)?;
+	let (input, _) = parse_delimiter(input)?;
+	let (input, _subsystem) = tag("smtp-in")(input)?;
+	let (input, _) = parse_delimiter(input)?;
+	let (input, _phase) = tag("data-line")(input)?;
+	let (input, _) = parse_delimiter(input)?;
+	let (input, session_id) = parse_string_parameter(input)?;
+	let (input, _) = parse_delimiter(input)?;
+	let (input, token) = parse_string_parameter(input)?;
+	let (input, _) = parse_delimiter(input)?;
+	let (input, data) = parse_data(input)?;
+	let entry = Entry {
+		session_id,
+		token,
+		data,
+	};
+	Ok((input, entry))
+}
diff --git a/src/handshake.rs b/src/handshake.rs
index c293387..9086587 100644
--- a/src/handshake.rs
+++ b/src/handshake.rs
@@ -6,7 +6,9 @@ pub fn read_config() {
 	let stdin = std::io::stdin();
 	loop {
 		buffer.clear();
-		stdin.read_line(&mut buffer).unwrap();
+		if stdin.read_line(&mut buffer).unwrap() == 0 {
+			crate::eof();
+		}
 		let entry = buffer.trim_end();
 		if entry == CONFIG_END {
 			return;
diff --git a/src/main.rs b/src/main.rs
index b0e76f1..255cacc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,39 @@
+mod entry;
 mod handshake;
 
+use entry::Entry;
+use std::io::{BufRead, BufReader};
+
+const DEFAULT_BUFF_SIZE: usize = 1024;
+
 fn main() {
 	handshake::read_config();
 	handshake::register_filter();
+	loop {
+		match read_line() {
+			Ok(entry) => {
+				if !entry.is_end_of_message() {
+					println!("Debug: {entry:?}");
+				} else {
+					println!("Debug: end of message: {entry:?}");
+				}
+			}
+			Err(err) => {
+				eprintln!("{err}");
+			}
+		}
+	}
+}
+
+pub fn read_line() -> Result<Entry, String> {
+	let mut buffer = Vec::with_capacity(DEFAULT_BUFF_SIZE);
+	let mut stdin = BufReader::new(std::io::stdin());
+	if stdin.read_until(b'\n', &mut buffer).unwrap() == 0 {
+		crate::eof();
+	}
+	Entry::from_bytes(&buffer)
+}
+
+fn eof() {
+	std::process::exit(0x2a)
 }