Handle the escapes of quote in the filters

filter-parser/src/error.rs

@@ -56,6 +56,7 @@ pub enum ErrorKind<'a> {
     InvalidPrimary,
     ExpectedEof,
     ExpectedValue,
+    MalformedValue,
     MissingClosingDelimiter(char),
     Char(char),
     InternalError(error::ErrorKind),
@@ -82,7 +83,7 @@ impl<'a> Error<'a> {
     pub fn char(self) -> char {
         match self.kind {
             ErrorKind::Char(c) => c,
-            _ => panic!("Internal filter parser error"),
+            error => panic!("Internal filter parser error: {:?}", error),
         }
     }
 }
@@ -117,6 +118,9 @@ impl<'a> Display for Error<'a> {
             ErrorKind::ExpectedValue if input.trim().is_empty() => {
                 writeln!(f, "Was expecting a value but instead got nothing.")?
             }
+            ErrorKind::MalformedValue => {
+                writeln!(f, "Malformed value: `{}`.", escaped_input)?
+            }
             ErrorKind::MissingClosingDelimiter(c) => {
                 writeln!(f, "Expression `{}` is missing the following closing delimiter: `{}`.", escaped_input, c)?
             }

filter-parser/src/lib.rs

@@ -62,29 +62,39 @@ pub type Span<'a> = LocatedSpan<&'a str, &'a str>;
 type IResult<'a, Ret> = nom::IResult<Span<'a>, Ret, Error<'a>>;
 
 #[derive(Debug, Clone, Eq)]
-pub struct Token<'a>(Span<'a>);
+pub struct Token<'a> {
+    /// The token in the original input, it should be used when possible.
+    span: Span<'a>,
+    /// If you need to modify the original input you can use the `value` field
+    /// to store your modified input.
+    value: Option<String>,
+}
 
 impl<'a> Deref for Token<'a> {
     type Target = &'a str;
 
     fn deref(&self) -> &Self::Target {
-        &self.0
+        &self.span
     }
 }
 
 impl<'a> PartialEq for Token<'a> {
     fn eq(&self, other: &Self) -> bool {
-        self.0.fragment() == other.0.fragment()
+        self.span.fragment() == other.span.fragment()
     }
 }
 
 impl<'a> Token<'a> {
-    pub fn new(position: Span<'a>) -> Self {
+    pub fn new(span: Span<'a>, value: Option<String>) -> Self {
-        Self(position)
+        Self { span, value }
+    }
+
+    pub fn value(&self) -> &str {
+        self.value.as_ref().map_or(&self.span, |value| value)
     }
 
     pub fn as_external_error(&self, error: impl std::error::Error) -> Error<'a> {
-        Error::new_from_external(self.0, error)
+        Error::new_from_external(self.span, error)
     }
 
     pub fn parse<T>(&self) -> Result<T, Error>
@@ -92,13 +102,13 @@ impl<'a> Token<'a> {
         T: FromStr,
         T::Err: std::error::Error,
     {
-        self.0.parse().map_err(|e| self.as_external_error(e))
+        self.span.parse().map_err(|e| self.as_external_error(e))
     }
 }
 
 impl<'a> From<Span<'a>> for Token<'a> {
     fn from(span: Span<'a>) -> Self {
-        Self(span)
+        Self { span, value: None }
     }
 }
 

filter-parser/src/value.rs

@@ -7,8 +7,54 @@ use nom::sequence::{delimited, terminated};
 use crate::error::NomErrorExt;
 use crate::{parse_geo_point, parse_geo_radius, Error, ErrorKind, IResult, Span, Token};
 
+/// This function goes through all chacaters in the [Span], if it finds any escaped character (`\`).
+/// It generate a new string with all `\` removed from the [Span].
+fn unescape(buf: Span, char_to_escape: char) -> String {
+    let to_escape = format!("\\{}", char_to_escape);
+    buf.replace(&to_escape, &char_to_escape.to_string())
+}
+
+use nom::{InputIter, InputLength, InputTake, Slice};
+
+/// Parse a value in quote. If it encounter an escaped quote it'll unescape it.
+fn quoted_by(quote: char, input: Span) -> IResult<Token> {
+    // empty fields / values are valid in json
+    if input.is_empty() {
+        return Ok((input.slice(input.input_len()..), input.into()));
+    }
+
+    let mut escaped = false;
+    let mut i = input.iter_indices();
+
+    while let Some((idx, c)) = i.next() {
+        match c {
+            c if c == quote => {
+                let (rem, output) = input.take_split(idx);
+                return Ok((rem, Token::new(output, escaped.then(|| unescape(output, quote)))));
+            }
+            '\\' => {
+                if let Some((_, c)) = i.next() {
+                    escaped |= c == quote;
+                } else {
+                    return Err(nom::Err::Error(Error::new_from_kind(
+                        input,
+                        ErrorKind::MalformedValue,
+                    )));
+                }
+            }
+            // if it was preceeded by a `\` or if it was anything else we can continue to advance
+            _ => (),
+        }
+    }
+
+    Ok((
+        input.slice(input.input_len()..),
+        Token::new(input, escaped.then(|| unescape(input, quote))),
+    ))
+}
+
 /// value          = WS* ~ ( word | singleQuoted | doubleQuoted) ~ WS*
-pub fn parse_value(input: Span) -> IResult<Token> {
+pub fn parse_value<'a>(input: Span<'a>) -> IResult<Token<'a>> {
     // to get better diagnostic message we are going to strip the left whitespaces from the input right now
     let (input, _) = take_while(char::is_whitespace)(input)?;
 
@@ -30,12 +76,10 @@ pub fn parse_value(input: Span) -> IResult<Token> {
         _ => (),
     }
 
-    // singleQuoted   = "'" .* all but quotes "'"
-    let simple_quoted = take_till(|c: char| c == '\'');
-    // doubleQuoted   = "\"" (word | spaces)* "\""
-    let double_quoted = take_till(|c: char| c == '"');
     // word           = (alphanumeric | _ | - | .)+
-    let word = take_while1(is_value_component);
+    let word = |input: Span<'a>| -> IResult<Token<'a>> {
+        take_while1(is_value_component)(input).map(|(s, t)| (s, t.into()))
+    };
 
     // this parser is only used when an error is encountered and it parse the
     // largest string possible that do not contain any “language” syntax.
@@ -48,20 +92,27 @@ pub fn parse_value(input: Span) -> IResult<Token> {
 
     terminated(
         alt((
-            delimited(char('\''), cut(simple_quoted), cut(char('\''))),
+            delimited(char('\''), cut(|input| quoted_by('\'', input)), cut(char('\''))),
-            delimited(char('"'), cut(double_quoted), cut(char('"'))),
+            delimited(char('"'), cut(|input| quoted_by('"', input)), cut(char('"'))),
             word,
         )),
         multispace0,
     )(input)
-    .map(|(s, t)| (s, t.into()))
+    // .map(|(s, t)| (s, t.into()))
     // if we found nothing in the alt it means the user specified something that was not recognized as a value
     .map_err(|e: nom::Err<Error>| {
         e.map_err(|_| Error::new_from_kind(error_word(input).unwrap().1, ErrorKind::ExpectedValue))
     })
-    // if we found encountered a failure it means the user really tried to input a value, but had an unmatched quote
     .map_err(|e| {
-        e.map_fail(|c| Error::new_from_kind(input, ErrorKind::MissingClosingDelimiter(c.char())))
+        e.map_fail(|failure| {
+            // if we found encountered a char failure it means the user had an unmatched quote
+            if matches!(failure.kind(), ErrorKind::Char(_)) {
+                Error::new_from_kind(input, ErrorKind::MissingClosingDelimiter(failure.char()))
+            } else {
+                // else we let the failure untouched
+                failure
+            }
+        })
     })
 }
 
@@ -81,7 +132,7 @@ pub mod test {
     use crate::tests::rtok;
 
     #[test]
-    fn name() {
+    fn test_span() {
         let test_case = [
             ("channel", rtok("", "channel")),
             (".private", rtok("", ".private")),
@@ -102,6 +153,7 @@ pub mod test {
             ("\"cha'nnel\"", rtok("'", "cha'nnel")),
             ("\"cha'nnel\"", rtok("'", "cha'nnel")),
             ("I'm tamo", rtok("'m tamo", "I")),
+            ("\"I'm \\\"super\\\" tamo\"", rtok("\"", "I'm \\\"super\\\" tamo")),
         ];
 
         for (input, expected) in test_case {
@@ -114,8 +166,116 @@ pub mod test {
                 expected,
                 result.unwrap_err()
             );
-            let value = result.unwrap().1;
+            let token = result.unwrap().1;
-            assert_eq!(value, expected, "Filter `{}` failed.", input);
+            assert_eq!(token, expected, "Filter `{}` failed.", input);
+        }
+    }
+
+    #[test]
+    fn test_escape_inside_double_quote() {
+        // (input, remaining, expected output token, output value)
+        let test_case = [
+            ("aaaa", "", rtok("", "aaaa"), "aaaa"),
+            (r#"aa"aa"#, r#""aa"#, rtok("", "aa"), "aa"),
+            (r#"aa\"aa"#, r#""#, rtok("", r#"aa\"aa"#), r#"aa"aa"#),
+            (r#"aa\\\aa"#, r#""#, rtok("", r#"aa\\\aa"#), r#"aa\\\aa"#),
+            (r#"aa\\"\aa"#, r#""\aa"#, rtok("", r#"aa\\"#), r#"aa\\"#),
+            (r#"aa\\\"\aa"#, r#""#, rtok("", r#"aa\\\"\aa"#), r#"aa\\"\aa"#),
+            (r#"\"\""#, r#""#, rtok("", r#"\"\""#), r#""""#),
+        ];
+
+        for (input, remaining, expected_tok, expected_val) in test_case {
+            let span = Span::new_extra(input, "");
+            let result = quoted_by('"', span);
+            assert!(result.is_ok());
+
+            let (rem, output) = result.unwrap();
+            assert_eq!(rem.to_string(), remaining);
+            assert_eq!(output, expected_tok);
+            assert_eq!(output.value(), expected_val.to_string());
+        }
+    }
+
+    #[test]
+    fn test_unescape() {
+        // double quote
+        assert_eq!(
+            unescape(Span::new_extra(r#"Hello \"World\""#, ""), '"'),
+            r#"Hello "World""#.to_string()
+        );
+        assert_eq!(
+            unescape(Span::new_extra(r#"Hello \\\"World\\\""#, ""), '"'),
+            r#"Hello \\"World\\""#.to_string()
+        );
+        // simple quote
+        assert_eq!(
+            unescape(Span::new_extra(r#"Hello \'World\'"#, ""), '\''),
+            r#"Hello 'World'"#.to_string()
+        );
+        assert_eq!(
+            unescape(Span::new_extra(r#"Hello \\\'World\\\'"#, ""), '\''),
+            r#"Hello \\'World\\'"#.to_string()
+        );
+    }
+
+    #[test]
+    fn test_value() {
+        let test_case = [
+            // (input, expected value, if a string was generated to hold the new value)
+            ("channel", "channel", false),
+            // All the base test, no escaped string should be generated
+            (".private", ".private", false),
+            ("I-love-kebab", "I-love-kebab", false),
+            ("but_snakes_is_also_good", "but_snakes_is_also_good", false),
+            ("parens(", "parens", false),
+            ("parens)", "parens", false),
+            ("not!", "not", false),
+            ("    channel", "channel", false),
+            ("channel     ", "channel", false),
+            ("    channel     ", "channel", false),
+            ("'channel'", "channel", false),
+            ("\"channel\"", "channel", false),
+            ("'cha)nnel'", "cha)nnel", false),
+            ("'cha\"nnel'", "cha\"nnel", false),
+            ("\"cha'nnel\"", "cha'nnel", false),
+            ("\" some spaces \"", " some spaces ", false),
+            ("\"cha'nnel\"", "cha'nnel", false),
+            ("\"cha'nnel\"", "cha'nnel", false),
+            ("I'm tamo", "I", false),
+            // escaped thing but not quote
+            (r#""\\""#, r#"\\"#, false),
+            (r#""\\\\\\""#, r#"\\\\\\"#, false),
+            (r#""aa\\aa""#, r#"aa\\aa"#, false),
+            // with double quote
+            (r#""Hello \"world\"""#, r#"Hello "world""#, true),
+            (r#""Hello \\\"world\\\"""#, r#"Hello \\"world\\""#, true),
+            (r#""I'm \"super\" tamo""#, r#"I'm "super" tamo"#, true),
+            (r#""\"\"""#, r#""""#, true),
+            // with simple quote
+            (r#"'Hello \'world\''"#, r#"Hello 'world'"#, true),
+            (r#"'Hello \\\'world\\\''"#, r#"Hello \\'world\\'"#, true),
+            (r#"'I\'m "super" tamo'"#, r#"I'm "super" tamo"#, true),
+            (r#"'\'\''"#, r#"''"#, true),
+        ];
+
+        for (input, expected, escaped) in test_case {
+            let input = Span::new_extra(input, input);
+            let result = parse_value(input);
+
+            assert!(
+                result.is_ok(),
+                "Filter `{:?}` was supposed to be parsed but failed with the following error: `{}`",
+                expected,
+                result.unwrap_err()
+            );
+            let token = result.unwrap().1;
+            assert_eq!(
+                token.value.is_some(),
+                escaped,
+                "Filter `{}` was not supposed to be escaped",
+                input
+            );
+            assert_eq!(token.value(), expected, "Filter `{}` failed.", input);
         }
     }