src/parser.rs

@@ -10,18 +10,17 @@
 //! [`GitConfig`]: crate::config::GitConfig
 
 use bstr::{BStr, ByteSlice};
-use nom::branch::alt;
 use nom::bytes::complete::{escaped, tag, take_till, take_while};
 use nom::character::complete::{char, none_of, one_of};
 use nom::character::{is_newline, is_space};
 use nom::combinator::{map, opt};
 use nom::error::{Error as NomError, ErrorKind};
-use nom::multi::{many0, many1};
 use nom::sequence::delimited;
 use nom::IResult;
+use nom::{branch::alt, multi::many0};
+use std::borrow::Cow;
 use std::fmt::Display;
 use std::iter::FusedIterator;
-use std::{borrow::Cow, error::Error};
 
 /// Syntactic events that occurs in the config. Despite all these variants
 /// holding a [`Cow`] instead over a simple reference, the parser will only emit
@@ -159,77 +158,20 @@ impl Display for ParsedComment<'_> {
     }
 }
 
-/// A parser error reports the one-indexed line number where the parsing error
-/// occurred, as well as the last parser node and the remaining data to be
-/// parsed.
+/// The various parsing failure reasons.
 #[derive(PartialEq, Debug)]
-pub struct ParserError<'a> {
-    line_number: usize,
-    last_attempted_parser: ParserNode,
-    parsed_until: &'a [u8],
+pub enum ParserError<'a> {
+    /// A parsing error occurred.
+    InvalidInput(nom::Err<NomError<&'a [u8]>>),
+    /// The config was successfully parsed, but we had extraneous data after the
+    /// config file.
+    ConfigHasExtraData(&'a BStr),
 }
 
-impl ParserError<'_> {
-    /// The one-indexed line number where the error occurred. This is determined
-    /// by the number of newlines that were successfully parsed.
-    pub fn line_number(&self) -> usize {
-        self.line_number + 1
-    }
-
-    /// The remaining data that was left unparsed.
-    pub fn remaining_data(&self) -> &[u8] {
-        self.parsed_until
-    }
-}
-
-impl Display for ParserError<'_> {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let data_size = self.parsed_until.len();
-        let data = std::str::from_utf8(self.parsed_until);
-        write!(
-            f,
-            "Got an unexpected token on line {} while trying to parse a {}: ",
-            self.line_number + 1,
-            self.last_attempted_parser,
-        )?;
-
-        match (data, data_size) {
-            (Ok(data), _) if data_size > 10 => write!(
-                f,
-                "'{}' ... ({} characters omitted)",
-                &data[..10],
-                data_size - 10
-            ),
-            (Ok(data), _) => write!(f, "'{}'", data),
-            (Err(_), _) if data_size > 10 => write!(
-                f,
-                "'{:02x?}' ... ({} characters omitted)",
-                &self.parsed_until[..10],
-                data_size - 10
-            ),
-            (Err(_), _) => write!(f, "'{:02x?}'", self.parsed_until),
-        }
-    }
-}
-
-impl Error for ParserError<'_> {}
-
-#[derive(PartialEq, Debug, Clone, Copy)]
-enum ParserNode {
-    SectionHeader,
-    ConfigName,
-    ConfigValue,
-    Comment,
-}
-
-impl Display for ParserNode {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Self::SectionHeader => write!(f, "section header"),
-            Self::ConfigName => write!(f, "config name"),
-            Self::ConfigValue => write!(f, "config value"),
-            Self::Comment => write!(f, "comment"),
-        }
+#[doc(hidden)]
+impl<'a> From<nom::Err<NomError<&'a [u8]>>> for ParserError<'a> {
+    fn from(e: nom::Err<NomError<&'a [u8]>>) -> Self {
+        Self::InvalidInput(e)
     }
 }
 
@@ -557,56 +499,19 @@ pub fn parse_from_str(input: &str) -> Result<Parser<'_>, ParserError> {
 /// This generally is due to either invalid names or if there's extraneous
 /// data succeeding valid `git-config` data.
 pub fn parse_from_bytes(input: &[u8]) -> Result<Parser<'_>, ParserError> {
-    let mut newlines = 0;
     let (i, frontmatter) = many0(alt((
         map(comment, Event::Comment),
         map(take_spaces, |whitespace| {
             Event::Whitespace(Cow::Borrowed(whitespace.into()))
         }),
-        map(take_newline, |(newline, counter)| {
-            newlines += counter;
+        map(take_newline, |newline| {
             Event::Newline(Cow::Borrowed(newline.into()))
         }),
-    )))(input.as_bytes())
-    // I don't think this can panic. many0 errors if the child parser returns
-    // a success where the input was not consumed, but alt will only return Ok
-    // if one of its children succeed. However, all of it's children are
-    // guaranteed to consume something if they succeed, so the Ok(i) == i case
-    // can never occur.
-    .expect("many0(alt(...)) panicked. Likely a bug in one of the children parser.");
+    )))(input.as_bytes())?;
+    let (i, sections) = many0(section)(i)?;
 
-    if i.is_empty() {
-        return Ok(Parser {
-            frontmatter,
-            sections: vec![],
-        });
-    }
-
-    let mut node = ParserNode::SectionHeader;
-
-    let maybe_sections = many1(|i| section(i, &mut node))(i);
-    let (i, sections) = maybe_sections.map_err(|_| ParserError {
-        line_number: newlines,
-        last_attempted_parser: node,
-        parsed_until: i,
-    })?;
-
-    let sections = sections
-        .into_iter()
-        .map(|(section, additional_newlines)| {
-            newlines += additional_newlines;
-            section
-        })
-        .collect();
-
-    // This needs to happen after we collect sections, otherwise the line number
-    // will be off.
     if !i.is_empty() {
-        return Err(ParserError {
-            line_number: newlines,
-            last_attempted_parser: node,
-            parsed_until: i,
-        });
+        return Err(ParserError::ConfigHasExtraData(i.into()));
     }
 
     Ok(Parser {
@@ -627,43 +532,28 @@ fn comment(i: &[u8]) -> IResult<&[u8], ParsedComment> {
     ))
 }
 
-fn section<'a, 'b>(
-    i: &'a [u8],
-    node: &'b mut ParserNode,
-) -> IResult<&'a [u8], (ParsedSection<'a>, usize)> {
+fn section(i: &[u8]) -> IResult<&[u8], ParsedSection> {
     let (i, section_header) = section_header(i)?;
-
-    let mut newlines = 0;
-    // todo: unhack this (manually implement many0 and alt to avoid closure moves)
-    let node = std::sync::Mutex::new(node);
     let (i, items) = many0(alt((
         map(take_spaces, |space| {
             vec![Event::Whitespace(Cow::Borrowed(space.into()))]
         }),
-        map(take_newline, |(newline, counter)| {
-            newlines += counter;
+        map(take_newline, |newline| {
             vec![Event::Newline(Cow::Borrowed(newline.into()))]
         }),
-        map(
-            |i| section_body(i, *node.lock().unwrap()),
-            |(key, values)| {
-                let mut vec = vec![Event::Key(Cow::Borrowed(key.into()))];
-                vec.extend(values);
-                vec
-            },
-        ),
+        map(section_body, |(key, values)| {
+            let mut vec = vec![Event::Key(Cow::Borrowed(key.into()))];
+            vec.extend(values);
+            vec
+        }),
         map(comment, |comment| vec![Event::Comment(comment)]),
     )))(i)?;
-
     Ok((
         i,
-        (
-            ParsedSection {
-                section_header,
-                events: items.into_iter().flatten().collect(),
-            },
-            newlines,
-        ),
+        ParsedSection {
+            section_header,
+            events: items.into_iter().flatten().collect(),
+        },
     ))
 }
 
@@ -698,6 +588,7 @@ fn section_header(i: &[u8]) -> IResult<&[u8], ParsedSectionHeader> {
     // Section header must be using modern subsection syntax at this point.
 
     let (i, whitespace) = take_spaces(i)?;
+
     let (i, subsection_name) = delimited(
         char('"'),
         opt(escaped(none_of("\"\\\n\0"), '\\', one_of(r#""\"#))),
@@ -718,19 +609,11 @@ fn section_header(i: &[u8]) -> IResult<&[u8], ParsedSectionHeader> {
     ))
 }
 
-fn section_body<'a, 'b>(
-    i: &'a [u8],
-    node: &'b mut ParserNode,
-) -> IResult<&'a [u8], (&'a [u8], Vec<Event<'a>>)> {
+fn section_body(i: &[u8]) -> IResult<&[u8], (&[u8], Vec<Event>)> {
     // maybe need to check for [ here
-    *node = ParserNode::ConfigName;
     let (i, name) = config_name(i)?;
-
     let (i, whitespace) = opt(take_spaces)(i)?;
-
-    *node = ParserNode::ConfigValue;
     let (i, value) = config_value(i)?;
-
     if let Some(whitespace) = whitespace {
         let mut events = vec![Event::Whitespace(Cow::Borrowed(whitespace.into()))];
         events.extend(value);
@@ -756,6 +639,7 @@ fn config_name(i: &[u8]) -> IResult<&[u8], &[u8]> {
             code: ErrorKind::Alpha,
         }));
     }
+
     take_while(|c: u8| (c as char).is_alphanumeric() || c == b'-')(i)
 }
 
@@ -867,7 +751,19 @@ fn value_impl(i: &[u8]) -> IResult<&[u8], Vec<Event>> {
 }
 
 fn take_spaces(i: &[u8]) -> IResult<&[u8], &[u8]> {
-    let (i, v) = take_while(|c| (c as char).is_ascii() && is_space(c))(i)?;
+    take_common(i, |c| (c as char).is_ascii() && is_space(c))
+}
+
+fn take_newline(i: &[u8]) -> IResult<&[u8], &[u8]> {
+    take_common(i, is_char_newline)
+}
+
+fn is_char_newline(c: u8) -> bool {
+    (c as char).is_ascii() && is_newline(c)
+}
+
+fn take_common<F: Fn(u8) -> bool>(i: &[u8], f: F) -> IResult<&[u8], &[u8]> {
+    let (i, v) = take_while(f)(i)?;
     if v.is_empty() {
         Err(nom::Err::Error(NomError {
             input: i,
@@ -878,24 +774,15 @@ fn take_spaces(i: &[u8]) -> IResult<&[u8], &[u8]> {
     }
 }
 
-fn take_newline(i: &[u8]) -> IResult<&[u8], (&[u8], usize)> {
-    let mut counter = 0;
-    let (i, v) = take_while(|c| (c as char).is_ascii() && is_newline(c))(i)?;
-    counter += v.len();
-    if v.is_empty() {
-        Err(nom::Err::Error(NomError {
-            input: i,
-            code: ErrorKind::Eof,
-        }))
-    } else {
-        Ok((i, (v, counter)))
-    }
+#[cfg(test)]
+fn fully_consumed<T>(t: T) -> (&'static [u8], T) {
+    (&[], t)
 }
 
 #[cfg(test)]
 mod comments {
     use super::*;
-    use crate::test_util::{comment as parsed_comment, fully_consumed};
+    use crate::test_util::comment as parsed_comment;
 
     #[test]
     fn semicolon() {
@@ -925,7 +812,7 @@ mod comments {
 #[cfg(test)]
 mod section_headers {
     use super::*;
-    use crate::test_util::{fully_consumed, section_header as parsed_section_header};
+    use crate::test_util::section_header as parsed_section_header;
 
     #[test]
     fn no_subsection() {
@@ -997,7 +884,6 @@ mod section_headers {
 #[cfg(test)]
 mod config_name {
     use super::*;
-    use crate::test_util::fully_consumed;
 
     #[test]
     fn just_name() {
@@ -1026,9 +912,8 @@ mod section_body {
 
     #[test]
     fn whitespace_is_not_ambigious() {
-        let mut node = ParserNode::SectionHeader;
         assert_eq!(
-            section_body(b"a =b", &mut node).unwrap().1,
+            section_body(b"a =b").unwrap().1,
             (
                 "a".as_bytes(),
                 vec![
@@ -1039,7 +924,7 @@ mod section_body {
             )
         );
         assert_eq!(
-            section_body(b"a= b", &mut node).unwrap().1,
+            section_body(b"a= b").unwrap().1,
             (
                 "a".as_bytes(),
                 vec![
@@ -1055,7 +940,7 @@ mod section_body {
 #[cfg(test)]
 mod value_no_continuation {
     use super::*;
-    use crate::test_util::{fully_consumed, value_event};
+    use crate::test_util::value_event;
 
     #[test]
     fn no_comment() {
@@ -1134,7 +1019,7 @@ mod value_no_continuation {
 #[cfg(test)]
 mod value_continuation {
     use super::*;
-    use crate::test_util::{fully_consumed, newline_event, value_done_event, value_not_done_event};
+    use crate::test_util::{newline_event, value_done_event, value_not_done_event};
 
     #[test]
     fn simple_continuation() {
@@ -1197,198 +1082,165 @@ mod value_continuation {
 mod section {
     use super::*;
     use crate::test_util::{
-        comment_event, fully_consumed, name_event, newline_event,
-        section_header as parsed_section_header, value_done_event, value_event,
-        value_not_done_event, whitespace_event,
+        comment_event, name_event, newline_event, section_header as parsed_section_header,
+        value_done_event, value_event, value_not_done_event, whitespace_event,
     };
 
     #[test]
     fn empty_section() {
-        let mut node = ParserNode::SectionHeader;
         assert_eq!(
-            section(b"[test]", &mut node).unwrap(),
-            fully_consumed((
-                ParsedSection {
-                    section_header: parsed_section_header("test", None),
-                    events: vec![]
-                },
-                0
-            )),
+            section(b"[test]").unwrap(),
+            fully_consumed(ParsedSection {
+                section_header: parsed_section_header("test", None),
+                events: vec![]
+            })
         );
     }
 
     #[test]
     fn simple_section() {
-        let mut node = ParserNode::SectionHeader;
         let section_data = br#"[hello]
             a = b
             c
             d = "lol""#;
         assert_eq!(
-            section(section_data, &mut node).unwrap(),
-            fully_consumed((
-                ParsedSection {
-                    section_header: parsed_section_header("hello", None),
-                    events: vec![
-                        newline_event(),
-                        whitespace_event("            "),
-                        name_event("a"),
-                        whitespace_event(" "),
-                        Event::KeyValueSeparator,
-                        whitespace_event(" "),
-                        value_event("b"),
-                        newline_event(),
-                        whitespace_event("            "),
-                        name_event("c"),
-                        value_event(""),
-                        newline_event(),
-                        whitespace_event("            "),
-                        name_event("d"),
-                        whitespace_event(" "),
-                        Event::KeyValueSeparator,
-                        whitespace_event(" "),
-                        value_event("\"lol\"")
-                    ]
-                },
-                3
-            ))
+            section(section_data).unwrap(),
+            fully_consumed(ParsedSection {
+                section_header: parsed_section_header("hello", None),
+                events: vec![
+                    newline_event(),
+                    whitespace_event("            "),
+                    name_event("a"),
+                    whitespace_event(" "),
+                    Event::KeyValueSeparator,
+                    whitespace_event(" "),
+                    value_event("b"),
+                    newline_event(),
+                    whitespace_event("            "),
+                    name_event("c"),
+                    value_event(""),
+                    newline_event(),
+                    whitespace_event("            "),
+                    name_event("d"),
+                    whitespace_event(" "),
+                    Event::KeyValueSeparator,
+                    whitespace_event(" "),
+                    value_event("\"lol\"")
+                ]
+            })
         )
     }
 
     #[test]
     fn section_single_line() {
-        let mut node = ParserNode::SectionHeader;
         assert_eq!(
-            section(b"[hello] c", &mut node).unwrap(),
-            fully_consumed((
-                ParsedSection {
-                    section_header: parsed_section_header("hello", None),
-                    events: vec![whitespace_event(" "), name_event("c"), value_event("")]
-                },
-                0
-            ))
+            section(b"[hello] c").unwrap(),
+            fully_consumed(ParsedSection {
+                section_header: parsed_section_header("hello", None),
+                events: vec![whitespace_event(" "), name_event("c"), value_event("")]
+            })
         );
     }
 
     #[test]
     fn section_very_commented() {
-        let mut node = ParserNode::SectionHeader;
         let section_data = br#"[hello] ; commentA
             a = b # commentB
             ; commentC
             ; commentD
             c = d"#;
         assert_eq!(
-            section(section_data, &mut node).unwrap(),
-            fully_consumed((
-                ParsedSection {
-                    section_header: parsed_section_header("hello", None),
-                    events: vec![
-                        whitespace_event(" "),
-                        comment_event(';', " commentA"),
-                        newline_event(),
-                        whitespace_event("            "),
-                        name_event("a"),
-                        whitespace_event(" "),
-                        Event::KeyValueSeparator,
-                        whitespace_event(" "),
-                        value_event("b"),
-                        whitespace_event(" "),
-                        comment_event('#', " commentB"),
-                        newline_event(),
-                        whitespace_event("            "),
-                        comment_event(';', " commentC"),
-                        newline_event(),
-                        whitespace_event("            "),
-                        comment_event(';', " commentD"),
-                        newline_event(),
-                        whitespace_event("            "),
-                        name_event("c"),
-                        whitespace_event(" "),
-                        Event::KeyValueSeparator,
-                        whitespace_event(" "),
-                        value_event("d"),
-                    ]
-                },
-                4
-            ))
+            section(section_data).unwrap(),
+            fully_consumed(ParsedSection {
+                section_header: parsed_section_header("hello", None),
+                events: vec![
+                    whitespace_event(" "),
+                    comment_event(';', " commentA"),
+                    newline_event(),
+                    whitespace_event("            "),
+                    name_event("a"),
+                    whitespace_event(" "),
+                    Event::KeyValueSeparator,
+                    whitespace_event(" "),
+                    value_event("b"),
+                    whitespace_event(" "),
+                    comment_event('#', " commentB"),
+                    newline_event(),
+                    whitespace_event("            "),
+                    comment_event(';', " commentC"),
+                    newline_event(),
+                    whitespace_event("            "),
+                    comment_event(';', " commentD"),
+                    newline_event(),
+                    whitespace_event("            "),
+                    name_event("c"),
+                    whitespace_event(" "),
+                    Event::KeyValueSeparator,
+                    whitespace_event(" "),
+                    value_event("d"),
+                ]
+            })
         );
     }
 
     #[test]
     fn complex_continuation() {
-        let mut node = ParserNode::SectionHeader;
         // This test is absolute hell. Good luck if this fails.
         assert_eq!(
-            section(
-                b"[section] a = 1    \"\\\"\\\na ; e \"\\\"\\\nd # \"b\t ; c",
-                &mut node
-            )
-            .unwrap(),
-            fully_consumed((
-                ParsedSection {
-                    section_header: parsed_section_header("section", None),
-                    events: vec![
-                        whitespace_event(" "),
-                        name_event("a"),
-                        whitespace_event(" "),
-                        Event::KeyValueSeparator,
-                        whitespace_event(" "),
-                        value_not_done_event(r#"1    "\""#),
-                        newline_event(),
-                        value_not_done_event(r#"a ; e "\""#),
-                        newline_event(),
-                        value_done_event("d"),
-                        whitespace_event(" "),
-                        comment_event('#', " \"b\t ; c"),
-                    ]
-                },
-                0
-            ))
+            section(b"[section] a = 1    \"\\\"\\\na ; e \"\\\"\\\nd # \"b\t ; c").unwrap(),
+            fully_consumed(ParsedSection {
+                section_header: parsed_section_header("section", None),
+                events: vec![
+                    whitespace_event(" "),
+                    name_event("a"),
+                    whitespace_event(" "),
+                    Event::KeyValueSeparator,
+                    whitespace_event(" "),
+                    value_not_done_event(r#"1    "\""#),
+                    newline_event(),
+                    value_not_done_event(r#"a ; e "\""#),
+                    newline_event(),
+                    value_done_event("d"),
+                    whitespace_event(" "),
+                    comment_event('#', " \"b\t ; c"),
+                ]
+            })
         );
     }
 
     #[test]
     fn quote_split_over_two_lines() {
-        let mut node = ParserNode::SectionHeader;
         assert_eq!(
-            section(b"[section \"a\"] b =\"\\\n;\";a", &mut node).unwrap(),
-            fully_consumed((
-                ParsedSection {
-                    section_header: parsed_section_header("section", (" ", "a")),
-                    events: vec![
-                        whitespace_event(" "),
-                        name_event("b"),
-                        whitespace_event(" "),
-                        Event::KeyValueSeparator,
-                        value_not_done_event("\""),
-                        newline_event(),
-                        value_done_event(";\""),
-                        comment_event(';', "a"),
-                    ]
-                },
-                0
-            ))
+            section(b"[section \"a\"] b =\"\\\n;\";a").unwrap(),
+            fully_consumed(ParsedSection {
+                section_header: parsed_section_header("section", (" ", "a")),
+                events: vec![
+                    whitespace_event(" "),
+                    name_event("b"),
+                    whitespace_event(" "),
+                    Event::KeyValueSeparator,
+                    value_not_done_event("\""),
+                    newline_event(),
+                    value_done_event(";\""),
+                    comment_event(';', "a"),
+                ]
+            })
         )
     }
 
     #[test]
     fn section_handles_extranous_whitespace_before_comment() {
-        let mut node = ParserNode::SectionHeader;
         assert_eq!(
-            section(b"[s]hello             #world", &mut node).unwrap(),
-            fully_consumed((
-                ParsedSection {
-                    section_header: parsed_section_header("s", None),
-                    events: vec![
-                        name_event("hello"),
-                        whitespace_event("             "),
-                        value_event(""),
-                        comment_event('#', "world"),
-                    ]
-                },
-                0
-            ))
+            section(b"[s]hello             #world").unwrap(),
+            fully_consumed(ParsedSection {
+                section_header: parsed_section_header("s", None),
+                events: vec![
+                    name_event("hello"),
+                    whitespace_event("             "),
+                    value_event(""),
+                    comment_event('#', "world"),
+                ]
+            })
         );
     }
 }

src/test_util.rs

@@ -67,7 +67,3 @@ pub(crate) fn comment(comment_tag: char, comment: &'static str) -> ParsedComment
         comment: Cow::Borrowed(comment.into()),
     }
 }
-
-pub(crate) fn fully_consumed<T>(t: T) -> (&'static [u8], T) {
-    (&[], t)
-}

tests/parser_integration_tests.rs

@@ -216,13 +216,3 @@ fn newline_events_are_merged() {
         vec![newline_custom("\n\n\n\n\n")]
     );
 }
-
-#[test]
-fn error() {
-    let input = "[core] a=b\n 4a=3";
-    println!("{}", parse_from_str(input).unwrap_err());
-    let input = "[core] a=b\n =3";
-    println!("{}", parse_from_str(input).unwrap_err());
-    let input = "[core";
-    println!("{}", parse_from_str(input).unwrap_err());
-}