Escape raw data

src/lib.rs

@@ -298,7 +298,7 @@ mod test {
  let mut output = std::io::Cursor::new(vec![]);
  let mut listener = Listener::new(Config {
  timeout: None,
- command: vec!["echo", "-n", "1234"]
+ command: vec!["echo", "1234"]
  .into_iter()
  .map(std::string::ToString::to_string)
  .collect(),
@@ -343,7 +343,7 @@ mod test {
  OK
  OK
  OK
- D 1234
+ D 1234%0A
  OK
  OK closing connection
  "},

src/response.rs

@@ -1,4 +1,7 @@
-use std::fmt::{self, Display, Formatter};
+use std::{
+ borrow::Cow,
+ fmt::{self, Display, Formatter},
+};
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum Response {
@@ -20,10 +23,85 @@ impl Display for Response {
  s.as_ref().map(|s| format!(" {s}")).unwrap_or_default(),
  ),
  Err(code, msg) => write!(f, "ERR {code} {msg}"),
- D(s) => write!(f, "D {s}"),
+ D(s) => write!(f, "D {}", escape(s)),
  Comment(s) => write!(f, "# {s}"),
  S(k, v) => write!(f, "S {k} {v}"),
  Inquire(k, v) => write!(f, "INQUIRE {k} {v}"),
  }
  }
 }
+
+/// Encode a string to be used in a response. It will percent escape `%`, `\n`, and `\r`.
+fn escape(s: &str) -> Cow<'_, str> {
+ // TODO: Split into lines of length at most 1000 bytes.
+ let mut s = s;
+ let mut escaped = String::with_capacity(s.len());
+
+ loop {
+ let unescaped_len = s
+ .chars()
+ .take_while(|c| !matches!(c, '%' | '\n' | '\r'))
+ .count();
+
+ let (unescaped, rest) = if unescaped_len >= s.len() {
+ if escaped.is_empty() {
+ return Cow::from(s);
+ }
+ (s, "")
+ } else {
+ s.split_at(unescaped_len)
+ };
+
+ if !unescaped.is_empty() {
+ escaped.push_str(unescaped);
+ }
+ if rest.is_empty() {
+ break;
+ }
+ let (first, rest) = rest.split_at(1);
+ match first {
+ "%" => escaped.push_str("%25"),
+ "\n" => escaped.push_str("%0A"),
+ "\r" => escaped.push_str("%0D"),
+ _ => unreachable!(),
+ }
+ s = rest;
+ }
+
+ Cow::from(escaped)
+}
+
+#[cfg(test)]
+mod test {
+ use std::borrow::Cow;
+
+ #[test]
+ fn escape() {
+ [
+ ("", ""),
+ ("a", "a"),
+ ("a\n", "a%0A"),
+ ("a\r", "a%0D"),
+ ("a%", "a%25"),
+ ("a%b", "a%25b"),
+ ("a%b\n", "a%25b%0A"),
+ ("a%b\r", "a%25b%0D"),
+ ("a\nb", "a%0Ab"),
+ ("a\rb", "a%0Db"),
+ ("a\nb\n", "a%0Ab%0A"),
+ ("a\rb\r", "a%0Db%0D"),
+ ("a\nb\r", "a%0Ab%0D"),
+ ("a\rb\n", "a%0Db%0A"),
+ ("a\nb\r\n", "a%0Ab%0D%0A"),
+ ("a\nb\r\nc", "a%0Ab%0D%0Ac"),
+ ("a\nb\r\nc\n", "a%0Ab%0D%0Ac%0A"),
+ ("a\nb\r\nc\nd", "a%0Ab%0D%0Ac%0Ad"),
+ ("a\nb\r\nc\nd\n", "a%0Ab%0D%0Ac%0Ad%0A"),
+ ]
+ .into_iter()
+ .map(|(input, expected)| (input, Cow::from(expected)))
+ .for_each(|(input, expected)| {
+ assert_eq!(super::escape(input), *expected);
+ });
+ }
+}