use smallvec::SmallVec; use crate::{    parse,    parse::{Event, EventRef, SectionData},}; /// Events that precede the first section in a configuration file.pub(crate) type FrontMatterEvents = SmallVec<[Event; 8]>; /// A `git-config` file parser.////// This parser exposes low-level syntactic events from a `git-config` file./// Generally speaking, you'll want to use [`File`] as it wraps/// around the parser to provide a higher-level abstraction to a `git-config`/// file, including querying, modifying, and updating values.////// This parser guarantees that the events emitted are sufficient to/// reconstruct a `git-config` file identical to the source `git-config`/// when writing it.////// # Differences between a `.ini` parser////// While the `git-config` format closely resembles the [`.ini` file format],/// there are subtle differences that make them incompatible. For one, the file/// format is not well defined, and there exists no formal specification to/// adhere to.////// For concrete examples, some notable differences are:/// - `git-config` sections permit subsections via either a quoted string///   (`[some-section "subsection"]`) or via the deprecated dot notation///   (`[some-section.subsection]`). Successful parsing these section names is not///   well defined in typical `.ini` parsers. This parser will handle these cases///   perfectly./// - Comment markers are not strictly defined either. This parser will always///   and only handle a semicolon or octothorpe (also known as a hash or number///   sign)./// - Global properties before the first section are accepted for compatibility///   with Git, even though they are uncommon in `.gitconfig` files./// - Only `\t`, `\n`, `\b` `\\` are valid escape characters./// - Quoted and semi-quoted values will be parsed (but quotes will be included///   in event outputs). An example of a semi-quoted value is `5"hello world"`,///   which should be interpreted as `5hello world` after///   [normalization][crate::value::normalize()]./// - Line continuations via a `\` character is supported (inside or outside of quotes)/// - Whitespace handling similarly follows the `git-config` specification as///   closely as possible, where excess whitespace after a non-quoted value are///   trimmed, and line continuations onto a new line with excess spaces are kept./// - Only equal signs (optionally padded by spaces) are valid name/value///   delimiters.////// Note that things such as case-sensitivity or duplicate sections are/// _not_ handled. This parser is a low level _syntactic_ interpreter/// and higher level wrappers around this parser should handle _semantic_ values./// This also means/// that string-like values are not interpreted. For example, `hello"world"`/// would be read at a high level as `helloworld` but this parser will return/// the former instead, with the extra quotes. This is because it is not the/// responsibility of the parser to interpret these values, and doing so would/// necessarily require a copy, which this parser avoids.////// # Trait Implementations////// - This struct does _not_ implement [`FromStr`] due to lifetime///   constraints implied on the required `from_str` method. Instead, it provides///   [`From<&'_ str>`].////// # Idioms////// If you do want to use this parser, there are some idioms that may help you/// with interpreting sequences of events.////// ## `Value` events do not immediately follow `Key` events////// Consider the following `git-config` example:////// ```text/// [core]///   autocrlf = input/// ```////// Because this parser guarantees near-perfect reconstruction, there are many/// non-significant events that occur in addition to the ones you may expect:////// ```/// # use gix_config::parse::{EventRef, Events};/// # let events = Events::from_str("[core]\n  autocrlf = input")?;/// assert_eq!(events.iter().collect::<Vec<_>>(), vec![///     EventRef::SectionHeader {///         name: "core".into(),///         separator: None,///         subsection_name: None,///     },///     EventRef::Newline("\n".into()),///     EventRef::Whitespace("  ".into()),///     EventRef::SectionValueName("autocrlf".into()),///     EventRef::Whitespace(" ".into()),///     EventRef::KeyValueSeparator,///     EventRef::Whitespace(" ".into()),///     EventRef::Value("input".into()),/// ]);/// # Ok::<_, gix_config::parse::Error>(())/// ```////// In particular, [`EventRef::SectionValueName`] and [`EventRef::Value`] are separated by two/// [`EventRef::Whitespace`] events around an [`EventRef::KeyValueSeparator`]. If the config instead/// had `autocrlf=input`, those whitespace events would not be present.////// ## `KeyValueSeparator` event is not guaranteed to emit////// Consider the following `git-config` example:////// ```text/// [core]///   autocrlf/// ```////// This is a valid config with a `autocrlf` key having an implicit `true`/// value. This means that there is not a `=` separating the key and value,/// which means that the corresponding event won't appear either:////// ```/// # use gix_config::parse::Events;/// # let section_data = "[core]\n  autocrlf";/// # let events = Events::from_str(section_data)?;/// # assert_eq!(/// #     events.iter().map(|event| event.to_string()).collect::<Vec<_>>(),/// #     vec!["[core]", "\n", "  ", "autocrlf", ""]/// # );/// # Ok::<_, gix_config::parse::Error>(())/// ```////// ## Quoted values are not unquoted////// Consider the following `git-config` example:////// ```text/// [core]/// autocrlf=true""/// filemode=fa"lse"/// ```////// Both these events, when fully processed, should normally be `true` and/// `false`. However, because this parser preserves the original event stream, we cannot process/// partially quoted values, such as the `false` example. As a result, to/// maintain consistency, the parser will just take all values as literals. The/// relevant event stream emitted is thus emitted as:////// ```/// # use gix_config::parse::Events;/// # let section_data = "[core]\nautocrlf=true\"\"\nfilemode=fa\"lse\"";/// # let events = Events::from_str(section_data)?;/// # assert_eq!(/// #     events.iter().map(|event| event.to_string()).collect::<Vec<_>>(),/// #     vec!["[core]", "\n", "autocrlf", "=", r#"true"""#, "\n", "filemode", "=", r#"fa"lse""#]/// # );/// # Ok::<_, gix_config::parse::Error>(())/// ```////// ## Whitespace after line continuations are part of the value////// Consider the following `git-config` example:////// ```text/// [some-section]/// file=a\///     c/// ```////// Because how `git-config` treats continuations, the whitespace preceding `c`/// are in fact part of the value of `file`. The fully interpreted key/value/// pair is actually `file=a    c`. As a result, the parser will provide this/// split value accordingly:////// ```/// # use gix_config::parse::Events;/// # let section_data = "[some-section]\nfile=a\\\n    c";/// # let events = Events::from_str(section_data)?;/// # assert_eq!(/// #     events.iter().map(|event| event.to_string()).collect::<Vec<_>>(),/// #     vec!["[some-section]", "\n", "file", "=", "a\\", "\n", "    c"]/// # );/// # Ok::<_, gix_config::parse::Error>(())/// ```////// [`File`]: crate::File/// [`.ini` file format]: https://en.wikipedia.org/wiki/INI_file/// [`git`'s documentation]: https://git-scm.com/docs/git-config#_configuration_file/// [`FromStr`]: std::str::FromStr/// [`From<&'_ str>`]: std::convert::From#[derive(Clone, Debug, Default)]pub struct Events {    pub(crate) backing: Vec<u8>,    /// Events seen before the first section.    pub(crate) frontmatter: FrontMatterEvents,    /// All parsed sections.    pub(crate) sections: Vec<SectionData>,} impl Events {    /// Attempt to parse the provided bytes.    ///    /// Inputs larger than [`u32::MAX`] bytes are rejected because event spans use 32-bit offsets.    ///    /// Use `filter` to only include those events for which it returns true.    pub fn from_bytes(input: &[u8], filter: Option<fn(EventRef<'_>) -> bool>) -> Result<Events, parse::Error> {        let mut header = None;        let mut events = Vec::with_capacity(256);        let mut frontmatter = FrontMatterEvents::default();        let mut sections = Vec::new();        // The parser emits offsets into the caller's input. Copy it only after successful parsing to        // make the returned events self-contained without allocating on parse errors.        parse::from_bytes::from_bytes(input, &mut |e: Event| match e {            Event::SectionHeader(next_header) => {                match header.take() {                    None => {                        frontmatter = std::mem::take(&mut events).into_iter().collect();                    }                    Some(prev_header) => {                        #[expect(                            clippy::drain_collect,                            reason = "Keep the scratch vector's allocation for parsing the next section."                        )]                        let section_events = events.drain(..).collect();                        sections.push(parse::SectionData {                            header: prev_header,                            events: section_events,                        });                    }                }                header = Some(match Event::SectionHeader(next_header) {                    Event::SectionHeader(h) => h,                    _ => unreachable!("BUG: event type changed"),                });            }            event => {                if filter.is_none_or(|f| f(event.as_ref_in(input))) {                    events.push(event);                }            }        })?;         match header {            None => {                frontmatter = events.into_iter().collect();            }            Some(prev_header) => {                sections.push(parse::SectionData {                    header: prev_header,                    events: std::mem::take(&mut events),                });            }        }        Ok(Events {            backing: input.to_vec(),            frontmatter,            sections,        })    }     /// Attempt to parse the provided `input` string.    ///    /// Prefer the [`from_bytes()`](Self::from_bytes()) method if UTF8 encoding    /// isn't guaranteed.    #[expect(        clippy::should_implement_trait,        reason = "the method has domain-specific semantics despite sharing a standard trait method name"    )]    pub fn from_str(input: &str) -> Result<Events, parse::Error> {        Self::from_bytes(input.as_bytes(), None)    }     /// Return all contained events as borrowed views.    pub fn iter(&self) -> impl Iterator<Item = EventRef<'_>> + '_ {        self.frontmatter().chain(self.sections().flat_map(SectionRef::iter))    }     /// Return all events before the first section as borrowed views.    pub fn frontmatter(&self) -> impl Iterator<Item = EventRef<'_>> + '_ {        self.frontmatter.iter().map(move |event| event.as_ref_in(&self.backing))    }     /// Return all parsed sections as borrowed views.    pub fn sections(&self) -> impl Iterator<Item = SectionRef<'_>> + '_ {        self.sections.iter().map(move |section| SectionRef {            header: &section.header,            events: &section.events,            backing: &self.backing,        })    }} impl TryFrom<&str> for Events {    type Error = parse::Error;     fn try_from(value: &str) -> Result<Self, Self::Error> {        Self::from_str(value)    }} impl TryFrom<&[u8]> for Events {    type Error = parse::Error;     fn try_from(value: &[u8]) -> Result<Self, Self::Error> {        Events::from_bytes(value, None)    }} /// A borrowed view of a parsed section.#[derive(Copy, Clone, Debug)]pub struct SectionRef<'a> {    header: &'a parse::section::HeaderData,    events: &'a [Event],    backing: &'a [u8],} impl<'a> SectionRef<'a> {    /// Return the section header as an event view.    pub fn header(&self) -> EventRef<'a> {        EventRef::SectionHeader {            name: self.header.name.as_bstr_in(self.backing),            separator: self                .header                .separator                .as_ref()                .map(|separator| separator.as_bstr_in(self.backing)),            subsection_name: self                .header                .subsection_name                .as_ref()                .map(|subsection_name| subsection_name.value_in(self.backing)),        }    }     /// Return the events contained in this section body.    pub fn body(self) -> impl Iterator<Item = EventRef<'a>> + 'a {        self.events.iter().map(move |event| event.as_ref_in(self.backing))    }     /// Return the complete event stream for this section, including its header.    pub fn iter(self) -> impl Iterator<Item = EventRef<'a>> + 'a {        std::iter::once(self.header()).chain(self.body())    }}