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//! A simple changelog parser, written in Rust. //! //! # Examples //! //! ```rust //! let changelog = "\ //! ## 0.1.2 - 2020-03-01 //! //! - Bug fixes. //! //! ## 0.1.1 - 2020-02-01 //! //! - Added `Foo`. //! - Added `Bar`. //! //! ## 0.1.0 - 2020-01-01 //! //! Initial release //! "; //! //! // Parse changelog. //! let changelog = parse_changelog::parse(changelog).unwrap(); //! //! // Get the latest release. //! assert_eq!(changelog[0].version, "0.1.2"); //! assert_eq!(changelog[0].title, "0.1.2 - 2020-03-01"); //! assert_eq!(changelog[0].notes, "- Bug fixes."); //! //! // Get the specified release. //! assert_eq!(changelog["0.1.0"].title, "0.1.0 - 2020-01-01"); //! assert_eq!(changelog["0.1.0"].notes, "Initial release"); //! assert_eq!(changelog["0.1.1"].title, "0.1.1 - 2020-02-01"); //! assert_eq!( //! changelog["0.1.1"].notes, //! "- Added `Foo`.\n\ //! - Added `Bar`." //! ); //! ``` //! //! The key of the map returned does not include prefixes such as //! "v", "Version ", etc. //! //! ```rust //! let changelog_a = "\ //! ## Version 0.1.0 - 2020-01-01 //! Initial release //! "; //! let changelog_b = "\ //! ## v0.1.0 - 2020-02-01 //! Initial release //! "; //! //! let changelog_a = parse_changelog::parse(changelog_a).unwrap(); //! let changelog_b = parse_changelog::parse(changelog_b).unwrap(); //! // Not `changelog_a["Version 0.1.0"]` //! assert_eq!(changelog_a["0.1.0"].version, "0.1.0"); //! assert_eq!(changelog_a["0.1.0"].title, "Version 0.1.0 - 2020-01-01"); //! assert_eq!(changelog_a["0.1.0"].notes, "Initial release"); //! // Not `changelog_b["v0.1.0"]` //! assert_eq!(changelog_b["0.1.0"].version, "0.1.0"); //! assert_eq!(changelog_b["0.1.0"].title, "v0.1.0 - 2020-02-01"); //! assert_eq!(changelog_b["0.1.0"].notes, "Initial release"); //! ``` //! //! # Format //! //! By default, this crate is intended to support markdown-based changelogs //! that have the title of each release starts with the version format based on //! [Semantic Versioning][semver]. (e.g., [Keep a Changelog][keepachangelog]'s //! changelog format.) //! //! ### Headings //! //! The heading for each release must be Atx-style (1-6 `#`) or //! Setext-style (`=` or `-` in a line under text), and the heading levels //! must match with other releases. //! //! Atx-style headings: //! //! ```markdown //! # 0.1.0 //! ``` //! //! ```markdown //! ## 0.1.0 //! ``` //! //! Setext-style headings: //! //! ```markdown //! 0.1.0 //! ===== //! ``` //! //! ```markdown //! 0.1.0 //! ----- //! ``` //! //! ### Titles //! //! The title of each release must start with a text or a link text (text with //! `[` and `]`) that starts with a valid version format. For example: //! //! ```markdown //! # [0.2.0] //! //! description... //! //! # 0.1.0 //! //! description... //! ``` //! //! You can also include characters before the version as prefix. //! //! ```text //! ## Version 0.1.0 //! ^^^^^^^^ //! ``` //! //! By default only "v", "Version " and "Release " are allowed as prefixes and //! can be customized using the [`Parser::prefix_format`] method. //! //! You can freely include characters after the version (this crate does not //! parse it). //! //! ```text //! # 0.1.0 - 2020-01-01 //! ^^^^^^^^^^^^^ //! ``` //! //! ### Versions //! //! ```text //! ## v0.1.0 -- 2020-01-01 //! ^^^^^ //! ``` //! //! The default version format is //! `MAJOR.MINOR.PATCH(-PRE_RELEASE)?(+BUILD_METADATA)?`, and is //! based on [Semantic Versioning][semver]. (Pre-release version and build //! metadata are optional.) //! //! This is parsed using the following regular expression: //! //! ```text //! ^\d+\.\d+\.\d+(-[\w\.-]+)?(\+[\w\.-]+)?$ //! ``` //! //! To customize the version format, use the [`Parser::version_format`] method. //! //! [keepachangelog]: https://keepachangelog.com/en/1.0.0 //! [semver]: https://semver.org/spec/v2.0.0.html #![doc(test( no_crate_inject, attr( deny(warnings, rust_2018_idioms, single_use_lifetimes), allow(dead_code, unused_variables) ) ))] #![forbid(unsafe_code)] #![warn(future_incompatible, rust_2018_idioms, single_use_lifetimes, unreachable_pub)] #![warn(missing_debug_implementations, missing_docs)] #![warn(clippy::all, clippy::default_trait_access)] mod error; use indexmap::IndexMap; use once_cell::sync::Lazy; use regex::Regex; use std::{iter::Peekable, mem, str::Lines}; pub use error::Error; type Result<T, E = Error> = std::result::Result<T, E>; /// A changelog. /// /// The key is a version, and the value is the release note for that version. /// /// The order is the same as the order written in the original text. (e.g., if /// [the latest version comes first][keepachangelog], `changelog[0]` is the /// release note for the latest version) /// /// This type is returned by [`parse`] function or [`Parser::parse`] method. /// /// [keepachangelog]: https://keepachangelog.com/en/1.0.0 pub type Changelog<'a> = IndexMap<&'a str, Release<'a>>; /// Parses release notes from the given `text`. /// /// This function uses the default version and prefix format. If you want to use /// another version format, use [`Parser::version_format`]. /// /// See crate level documentation for changelog and version format supported /// by default. /// /// # Errors /// /// Returns an error if any of the following: /// /// - There are multiple release notes for one version. /// - No release was found. This usually means that the changelog isn't /// written in the supported format. pub fn parse(text: &str) -> Result<Changelog<'_>> { Parser::new().parse(text) } /// A release note for a version. #[derive(Debug, Clone)] #[non_exhaustive] pub struct Release<'a> { /// The version of this release. /// /// ```text /// ## Version 0.1.0 -- 2020-01-01 /// ^^^^^ /// ``` /// /// This is the same value as the key of the [`Changelog`] type. pub version: &'a str, /// The title of this release. /// /// ```text /// ## Version 0.1.0 -- 2020-01-01 /// ^^^^^^^^^^^^^^^^^^^^^^^^^^^ /// ``` /// /// Note that leading and trailing [whitespaces](char::is_whitespace) have /// been removed. pub title: &'a str, /// The descriptions of this release. /// /// Note that leading and trailing newlines have been removed. pub notes: String, } impl Release<'_> { fn new() -> Self { Self { version: "", title: "", notes: String::new() } } } /// A changelog parser. #[derive(Debug, Default)] pub struct Parser { /// Version format. e.g., "0.1.0" in "# v0.1.0 (2020-01-01)". /// /// If `None`, `DEFAULT_VERSION_FORMAT` is used. version: Option<Regex>, /// Prefix format. e.g., "v" in "# v0.1.0 (2020-01-01)", "Version " in /// "# Version 0.1.0 (2020-01-01)". /// /// If `None`, `DEFAULT_PREFIX_FORMAT` is used. prefix: Option<Regex>, } static DEFAULT_PREFIX_FORMAT: Lazy<Regex> = Lazy::new(|| Regex::new(r"^(v|Version |Release )?").unwrap()); static DEFAULT_VERSION_FORMAT: Lazy<Regex> = Lazy::new(|| Regex::new(r"^\d+\.\d+\.\d+(-[\w\.-]+)?(\+[\w\.-]+)?$").unwrap()); impl Parser { /// Creates a new changelog parser. pub fn new() -> Self { Self::default() } /// Sets the version format. /// /// ```text /// ## v0.1.0 -- 2020-01-01 /// ^^^^^ /// ``` /// /// The default version format is based on [Semantic Versioning][semver] /// and is the following regular expression: /// /// ```text /// ^\d+\.\d+\.\d+(-[\w\.-]+)?(\+[\w\.-]+)? /// ``` /// /// **Note**: Most projects that adopt [Semantic Versioning][semver] do not /// need to change this. /// /// To customize the text before the version number (e.g., "v" in "# v0.1.0", /// "Version " in "# Version 0.1.0", etc.), use the [`prefix_format`] method /// instead of this method. /// /// # Errors /// /// Returns an error if any of the following: /// /// - The specified format is not a valid regular expression or supported by /// [regex] crate. /// - The specified format is empty or contains only /// [whitespace](char::is_whitespace). /// /// [`parse`]: Self::parse /// [`prefix_format`]: Self::prefix_format /// [regex]: https://docs.rs/regex /// [semver]: https://semver.org/spec/v2.0.0.html pub fn version_format(&mut self, version_format: &str) -> Result<&mut Self> { if version_format.trim().is_empty() { return Err(Error::Format("empty or whitespace version format".into())); } self.version = Some(Regex::new(version_format)?); Ok(self) } /// Sets the prefix format. /// /// "Prefix" means the range from the first non-whitespace character after /// heading to the character before the version (including whitespace /// characters). For example: /// /// ```text /// ## Version 0.1.0 -- 2020-01-01 /// ^^^^^^^^ /// ``` /// ```text /// ## v0.1.0 -- 2020-01-01 /// ^ /// ``` /// /// The default prefix format is the following regular expression: /// /// ```text /// ^(v|Version |Release )? /// ``` /// /// # Errors /// /// Returns an error if any of the following: /// /// - The specified format is not a valid regular expression or supported by /// [regex] crate. /// - The specified format is empty or contains only /// [whitespace](char::is_whitespace). /// /// [`parse`]: Self::parse /// [`version_format`]: Self::version_format /// [regex]: https://docs.rs/regex pub fn prefix_format(&mut self, prefix_format: &str) -> Result<&mut Self> { if prefix_format.trim().is_empty() { return Err(Error::Format("empty or whitespace version format".into())); } self.prefix = Some(Regex::new(prefix_format)?); Ok(self) } fn get_version_format(&self) -> &Regex { self.version.as_ref().unwrap_or(&DEFAULT_VERSION_FORMAT) } fn get_prefix_format(&self) -> &Regex { self.prefix.as_ref().unwrap_or(&DEFAULT_PREFIX_FORMAT) } /// Parses release notes from the given `text`. /// /// See crate level documentation for changelog and version format supported /// by default. /// /// # Errors /// /// Returns an error if any of the following: /// /// - There are multiple release notes for one version. /// - No release was found. This usually means that the changelog isn't /// written in the supported format, or that the specified format is wrong /// if you specify your own format. pub fn parse<'a>(&self, text: &'a str) -> Result<Changelog<'a>> { parse_inner(self, text) } } fn parse_inner<'a>(parser: &Parser, text: &'a str) -> Result<Changelog<'a>> { const LN: char = '\n'; let version_format = parser.get_version_format(); let prefix_format = parser.get_prefix_format(); let mut map = IndexMap::new(); let mut insert_release = |mut cur_release: Release<'a>| { debug_assert!(!cur_release.version.is_empty()); while cur_release.notes.ends_with(LN) { // Remove trailing newlines. cur_release.notes.pop(); } if let Some(release) = map.insert(cur_release.version, cur_release) { return Err(Error::Parse(format!("multiple release notes for '{}'", release.version))); } Ok(()) }; let lines = &mut text.lines().peekable(); let mut cur_release = Release::new(); // If `true`, we are in a release section. let mut on_release = false; // If `true`, we are in a code block ("```"). let mut on_code_block = false; // If `true`, we are in a comment (`<!--` and `-->`). let mut on_comment = false; // The heading level of release sections. let mut level = None; while let Some(line) = lines.next() { let heading = heading(line, lines); if heading.is_none() || on_code_block || on_comment { if trim(line).starts_with("```") { on_code_block = !on_code_block; } if !on_code_block { const OPEN: &str = "<!--"; const CLOSE: &str = "-->"; let mut ll = Some(line); while let Some(l) = ll { match (l.find(OPEN), l.find(CLOSE)) { (None, None) => {} // <!-- ... (Some(_), None) => on_comment = true, // ... --> (None, Some(_)) => on_comment = false, (Some(open), Some(close)) => { if open < close { // <!-- ... --> on_comment = false; ll = l.get(close + CLOSE.len()..); } else { // --> ... <!-- on_comment = true; ll = l.get(open + OPEN.len()..); } continue; } } break; } } // Non-heading lines are always considered part of the current // section. if on_release { cur_release.notes.push_str(line); cur_release.notes.push(LN); } continue; } let heading = heading.unwrap(); let mut unlinked = unlink(heading.text); if let Some(m) = prefix_format.find(unlinked) { unlinked = &unlinked[m.end()..]; } let unlinked = unlink(unlinked.splitn(2, char::is_whitespace).next().unwrap()); let version = match version_format.find(unlinked) { Some(m) => &unlinked[m.start()..m.end()], None => { if level.map_or(true, |l| heading.level <= l) { // Ignore non-release sections that have the same or higher // heading levels as release sections. on_release = false; } else if on_release { // Otherwise, it is considered part of the current section. cur_release.notes.push_str(line); cur_release.notes.push(LN); } continue; } }; if mem::replace(&mut on_release, true) { // end of prev release insert_release(mem::replace(&mut cur_release, Release::new()))?; } cur_release.version = version; cur_release.title = heading.text; level.get_or_insert(heading.level); if heading.style == HeadingStyle::Setext { // Remove an underline after a Setext-style heading. lines.next(); } while let Some(next) = lines.peek() { if next.trim().is_empty() { // Remove newlines after a heading. lines.next(); } else { break; } } } if !cur_release.version.is_empty() { insert_release(cur_release)?; } if map.is_empty() { return Err(Error::Parse("no release was found".into())); } Ok(map) } struct Heading<'a> { text: &'a str, level: usize, style: HeadingStyle, } #[derive(Eq, PartialEq)] enum HeadingStyle { /// Atx-style headings use 1-6 `#` characters at the start of the line, /// corresponding to header levels 1-6. Atx, /// Setext-style headings are “underlined” using equal signs `=` (for /// first-level headings) and dashes `-` (for second-level headings). Setext, } fn heading<'a>(line: &'a str, lines: &mut Peekable<Lines<'_>>) -> Option<Heading<'a>> { static ALL_EQUAL_SIGNS: Lazy<Regex> = Lazy::new(|| Regex::new("^=+$").unwrap()); static ALL_DASHES: Lazy<Regex> = Lazy::new(|| Regex::new("^-+$").unwrap()); let line = trim(line); if line.starts_with('#') { let mut level = 0; while line[level..].starts_with('#') { level += 1; } if level <= 6 { Some(Heading { text: line[level..].trim(), level, style: HeadingStyle::Atx }) } else { None } } else if let Some(next) = lines.peek() { let next = trim(next); if ALL_EQUAL_SIGNS.is_match(next) { Some(Heading { text: line, level: 1, style: HeadingStyle::Setext }) } else if ALL_DASHES.is_match(next) { Some(Heading { text: line, level: 2, style: HeadingStyle::Setext }) } else { None } } else { None } } fn trim(s: &str) -> &str { let mut cnt = 0; while s[cnt..].starts_with(' ') { cnt += 1; } // Indents less than 4 are ignored. if cnt < 4 { s[cnt..].trim_end() } else { s.trim_end() } } /// If a leading `[` or trailing `]` exists, returns a string with it removed. /// /// This is not a full "unlink" on markdown, but this is enough as this crate /// does not parse a string at the end of headings. fn unlink(mut s: &str) -> &str { s = s.strip_prefix('[').unwrap_or(s); s.strip_suffix(']').unwrap_or(s) }