use crate::file::{LookupTreeNode, SectionBody, SectionId};use crate::parser::{ParsedSectionHeader, SectionHeaderName};use std::collections::{HashMap, VecDeque}; /// High level `git-config` reader and writer.////// This is the full-featured implementation that can deserialize, serialize,/// and edit `git-config` files without loss of whitespace or comments. As a/// result, it's lot more complex than it's read-only variant,/// [`ResolvedGitConfig`] that exposes a [`HashMap`]-like interface. Users that/// only need to read `git-config` files should use that instead.////// Internally, this uses various acceleration data structures to improve/// performance of the typical usage behavior of many lookups and relatively/// fewer insertions.////// # Multivar behavior////// `git` is flexible enough to allow users to set a key multiple times in/// any number of identically named sections. When this is the case, the key/// is known as a "multivar". In this case, `raw_value` follows the/// "last one wins" approach that `git-config` internally uses for multivar/// resolution.////// Concretely, the following config has a multivar, `a`, with the values/// of `b`, `c`, and `d`, while `e` is a single variable with the value/// `f g h`.////// ```text/// [core]///     a = b///     a = c/// [core]///     a = d///     e = f g h/// ```////// Calling methods that fetch or set only one value (such as [`raw_value`])/// key `a` with the above config will fetch `d` or replace `d`, since the last/// valid config key/value pair is `a = d`:////// ```/// # use std::borrow::Cow;/// # use std::convert::TryFrom;/// # let git_config = git_config::File::try_from("[core]a=b\n[core]\na=c\na=d").unwrap();/// assert_eq!(git_config.raw_value("core", None, "a").unwrap(), Cow::Borrowed("d".as_bytes()));/// ```////// Consider the `multi` variants of the methods instead, if you want to work/// with all values instead.////// [`ResolvedGitConfig`]: crate::file::ResolvedGitConfig/// [`raw_value`]: Self::raw_value#[derive(PartialEq, Eq, Clone, Debug, Default)]pub struct File<'event> {    /// The list of events that occur before an actual section. Since a    /// `git-config` file prohibits global values, this vec is limited to only    /// comment, newline, and whitespace events.    pub(crate) frontmatter_events: SectionBody<'event>,    /// Section name and subsection name to section id lookup tree. This is    /// effectively a n-tree (opposed to a binary tree) that can have a height    /// of at most three (including an implicit root node).    pub(crate) section_lookup_tree: HashMap<SectionHeaderName<'event>, Vec<LookupTreeNode<'event>>>,    /// SectionId to section mapping. The value of this HashMap contains actual    /// events.    ///    /// This indirection with the SectionId as the key is critical to flexibly    /// supporting `git-config` sections, as duplicated keys are permitted.    pub(crate) sections: HashMap<SectionId, SectionBody<'event>>,    pub(crate) section_headers: HashMap<SectionId, ParsedSectionHeader<'event>>,    /// Internal monotonically increasing counter for section ids.    pub(crate) section_id_counter: usize,    /// Section order for output ordering.    pub(crate) section_order: VecDeque<SectionId>,}