use nom::branch::alt; use nom::bytes::complete::{take_till, take_while, take_while1}; use nom::character::complete::{char, multispace0}; use nom::combinator::cut; use nom::sequence::{delimited, terminated}; use nom::{InputIter, InputLength, InputTake, Slice}; use crate::error::{ExpectedValueKind, NomErrorExt}; use crate::{ parse_geo, parse_geo_bounding_box, parse_geo_distance, parse_geo_point, parse_geo_radius, Error, ErrorKind, IResult, Span, Token, }; /// This function goes through all characters in the [Span] if it finds any escaped character (`\`). /// It generates 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()) } /// Parse a value in quote. If it encounter an escaped quote it'll unescape it. fn quoted_by(quote: char, input: Span) -> IResult { // 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() { if c == quote { let (rem, output) = input.take_split(idx); return Ok((rem, Token::new(output, escaped.then(|| unescape(output, quote))))); } else if c == '\\' { 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))), )) } // word = (alphanumeric | _ | - | .)+ except for reserved keywords pub fn word_not_keyword<'a>(input: Span<'a>) -> IResult> { let (input, word): (_, Token<'a>) = take_while1(is_value_component)(input).map(|(s, t)| (s, t.into()))?; if is_keyword(word.value()) { return Err(nom::Err::Error(Error::new_from_kind( input, ErrorKind::ReservedKeyword(word.value().to_owned()), ))); } Ok((input, word)) } // word = {tag} pub fn word_exact<'a, 'b: 'a>(tag: &'b str) -> impl Fn(Span<'a>) -> IResult<'a, Token<'a>> { move |input| { let (input, word): (_, Token<'a>) = take_while1(is_value_component)(input).map(|(s, t)| (s, t.into()))?; if word.value() == tag { Ok((input, word)) } else { Err(nom::Err::Error(Error::new_from_kind( input, ErrorKind::InternalError(nom::error::ErrorKind::Tag), ))) } } } /// value = WS* ( word | singleQuoted | doubleQuoted) WS+ pub fn parse_value(input: Span) -> IResult { // 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)?; // then, we want to check if the user is misusing a geo expression // This expression can’t finish without error. // We want to return an error in case of failure. let geo_reserved_parse_functions = [parse_geo_point, parse_geo_distance, parse_geo]; for parser in geo_reserved_parse_functions { if let Err(err) = parser(input) { if err.is_failure() { return Err(err); } } } match parse_geo_radius(input) { Ok(_) => { return Err(nom::Err::Failure(Error::new_from_kind(input, ErrorKind::MisusedGeoRadius))) } // if we encountered a failure it means the user badly wrote a _geoRadius filter. // But instead of showing them how to fix his syntax we are going to tell them they should not use this filter as a value. Err(e) if e.is_failure() => { return Err(nom::Err::Failure(Error::new_from_kind(input, ErrorKind::MisusedGeoRadius))) } _ => (), } match parse_geo_bounding_box(input) { Ok(_) => { return Err(nom::Err::Failure(Error::new_from_kind( input, ErrorKind::MisusedGeoBoundingBox, ))) } // if we encountered a failure it means the user badly wrote a _geoBoundingBox filter. // But instead of showing them how to fix his syntax we are going to tell them they should not use this filter as a value. Err(e) if e.is_failure() => { return Err(nom::Err::Failure(Error::new_from_kind( input, ErrorKind::MisusedGeoBoundingBox, ))) } _ => (), } // this parser is only used when an error is encountered and it parse the // largest string possible that do not contain any “language” syntax. // If we try to parse `name = 🦀 AND language = rust` we want to return an // error saying we could not parse `🦀`. Not that no value were found or that // we could note parse `🦀 AND language = rust`. // we want to remove the space before entering the alt because if we don't, // when we create the errors from the output of the alt we have spaces everywhere let error_word = take_till::<_, _, Error>(is_syntax_component); let (input, value) = terminated( alt(( delimited(char('\''), cut(|input| quoted_by('\'', input)), cut(char('\''))), delimited(char('"'), cut(|input| quoted_by('"', input)), cut(char('"'))), word_not_keyword, )), multispace0, )(input) // 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| { e.map_err(|error| { let expected_value_kind = if matches!(error.kind(), ErrorKind::ReservedKeyword(_)) { ExpectedValueKind::ReservedKeyword } else { ExpectedValueKind::Other }; Error::new_from_kind( error_word(input).unwrap().1, ErrorKind::ExpectedValue(expected_value_kind), ) }) }) .map_err(|e| { 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 } }) })?; Ok((input, value)) } fn is_value_component(c: char) -> bool { c.is_alphanumeric() || ['_', '-', '.'].contains(&c) } fn is_syntax_component(c: char) -> bool { c.is_whitespace() || ['(', ')', '=', '<', '>', '!'].contains(&c) } fn is_keyword(s: &str) -> bool { matches!( s, "AND" | "OR" | "IN" | "NOT" | "TO" | "EXISTS" | "IS" | "NULL" | "EMPTY" | "_geoRadius" | "_geoBoundingBox" ) } #[cfg(test)] pub mod test { use nom::Finish; use super::*; use crate::tests::rtok; #[test] fn test_span() { let test_case = [ ("channel", rtok("", "channel")), (".private", rtok("", ".private")), ("I-love-kebab", rtok("", "I-love-kebab")), ("but_snakes_is_also_good", rtok("", "but_snakes_is_also_good")), ("parens(", rtok("", "parens")), ("parens)", rtok("", "parens")), ("not!", rtok("", "not")), (" channel", rtok(" ", "channel")), ("channel ", rtok("", "channel")), (" channel ", rtok(" ", "channel")), ("'channel'", rtok("'", "channel")), ("\"channel\"", rtok("\"", "channel")), ("'cha)nnel'", rtok("'", "cha)nnel")), ("'cha\"nnel'", rtok("'", "cha\"nnel")), ("\"cha'nnel\"", rtok("\"", "cha'nnel")), ("\" some spaces \"", rtok("\"", " some spaces ")), ("\"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 { 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, 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); } } #[test] fn diagnostic() { let test_case = [ ("🦀", "🦀"), (" 🦀", "🦀"), ("🦀 AND crab = truc", "🦀"), ("🦀_in_name", "🦀_in_name"), (" (name = ...", ""), ]; for (input, expected) in test_case { let input = Span::new_extra(input, input); let result = parse_value(input); assert!( result.is_err(), "Filter `{}` wasn’t supposed to be parsed but it did with the following result: `{:?}`", expected, result.unwrap() ); // get the inner string referenced in the error let value = *result.finish().unwrap_err().context().fragment(); assert_eq!(value, expected, "Filter `{}` was supposed to fail with the following value: `{}`, but it failed with: `{}`.", input, expected, value); } } }