--- /dev/null
+// Formatting and tools for comments.
+
+use std::{self, borrow::Cow, iter};
+
+use itertools::{multipeek, MultiPeek};
+use rustc_span::Span;
+
+use crate::config::Config;
+use crate::rewrite::RewriteContext;
+use crate::shape::{Indent, Shape};
+use crate::string::{rewrite_string, StringFormat};
+use crate::utils::{
+ count_newlines, first_line_width, last_line_width, trim_left_preserve_layout, unicode_str_width,
+};
+use crate::{ErrorKind, FormattingError};
+
+fn is_custom_comment(comment: &str) -> bool {
+ if !comment.starts_with("//") {
+ false
+ } else if let Some(c) = comment.chars().nth(2) {
+ !c.is_alphanumeric() && !c.is_whitespace()
+ } else {
+ false
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub(crate) enum CommentStyle<'a> {
+ DoubleSlash,
+ TripleSlash,
+ Doc,
+ SingleBullet,
+ DoubleBullet,
+ Exclamation,
+ Custom(&'a str),
+}
+
+fn custom_opener(s: &str) -> &str {
+ s.lines().next().map_or("", |first_line| {
+ first_line
+ .find(' ')
+ .map_or(first_line, |space_index| &first_line[0..=space_index])
+ })
+}
+
+impl<'a> CommentStyle<'a> {
+ /// Returns `true` if the commenting style covers a line only.
+ pub(crate) fn is_line_comment(&self) -> bool {
+ match *self {
+ CommentStyle::DoubleSlash
+ | CommentStyle::TripleSlash
+ | CommentStyle::Doc
+ | CommentStyle::Custom(_) => true,
+ _ => false,
+ }
+ }
+
+ /// Returns `true` if the commenting style can span over multiple lines.
+ pub(crate) fn is_block_comment(&self) -> bool {
+ match *self {
+ CommentStyle::SingleBullet | CommentStyle::DoubleBullet | CommentStyle::Exclamation => {
+ true
+ }
+ _ => false,
+ }
+ }
+
+ /// Returns `true` if the commenting style is for documentation.
+ pub(crate) fn is_doc_comment(&self) -> bool {
+ match *self {
+ CommentStyle::TripleSlash | CommentStyle::Doc => true,
+ _ => false,
+ }
+ }
+
+ pub(crate) fn opener(&self) -> &'a str {
+ match *self {
+ CommentStyle::DoubleSlash => "// ",
+ CommentStyle::TripleSlash => "/// ",
+ CommentStyle::Doc => "//! ",
+ CommentStyle::SingleBullet => "/* ",
+ CommentStyle::DoubleBullet => "/** ",
+ CommentStyle::Exclamation => "/*! ",
+ CommentStyle::Custom(opener) => opener,
+ }
+ }
+
+ pub(crate) fn closer(&self) -> &'a str {
+ match *self {
+ CommentStyle::DoubleSlash
+ | CommentStyle::TripleSlash
+ | CommentStyle::Custom(..)
+ | CommentStyle::Doc => "",
+ CommentStyle::SingleBullet | CommentStyle::DoubleBullet | CommentStyle::Exclamation => {
+ " */"
+ }
+ }
+ }
+
+ pub(crate) fn line_start(&self) -> &'a str {
+ match *self {
+ CommentStyle::DoubleSlash => "// ",
+ CommentStyle::TripleSlash => "/// ",
+ CommentStyle::Doc => "//! ",
+ CommentStyle::SingleBullet | CommentStyle::DoubleBullet | CommentStyle::Exclamation => {
+ " * "
+ }
+ CommentStyle::Custom(opener) => opener,
+ }
+ }
+
+ pub(crate) fn to_str_tuplet(&self) -> (&'a str, &'a str, &'a str) {
+ (self.opener(), self.closer(), self.line_start())
+ }
+}
+
+pub(crate) fn comment_style(orig: &str, normalize_comments: bool) -> CommentStyle<'_> {
+ if !normalize_comments {
+ if orig.starts_with("/**") && !orig.starts_with("/**/") {
+ CommentStyle::DoubleBullet
+ } else if orig.starts_with("/*!") {
+ CommentStyle::Exclamation
+ } else if orig.starts_with("/*") {
+ CommentStyle::SingleBullet
+ } else if orig.starts_with("///") && orig.chars().nth(3).map_or(true, |c| c != '/') {
+ CommentStyle::TripleSlash
+ } else if orig.starts_with("//!") {
+ CommentStyle::Doc
+ } else if is_custom_comment(orig) {
+ CommentStyle::Custom(custom_opener(orig))
+ } else {
+ CommentStyle::DoubleSlash
+ }
+ } else if (orig.starts_with("///") && orig.chars().nth(3).map_or(true, |c| c != '/'))
+ || (orig.starts_with("/**") && !orig.starts_with("/**/"))
+ {
+ CommentStyle::TripleSlash
+ } else if orig.starts_with("//!") || orig.starts_with("/*!") {
+ CommentStyle::Doc
+ } else if is_custom_comment(orig) {
+ CommentStyle::Custom(custom_opener(orig))
+ } else {
+ CommentStyle::DoubleSlash
+ }
+}
+
+/// Returns true if the last line of the passed string finishes with a block-comment.
+pub(crate) fn is_last_comment_block(s: &str) -> bool {
+ s.trim_end().ends_with("*/")
+}
+
+/// Combine `prev_str` and `next_str` into a single `String`. `span` may contain
+/// comments between two strings. If there are such comments, then that will be
+/// recovered. If `allow_extend` is true and there is no comment between the two
+/// strings, then they will be put on a single line as long as doing so does not
+/// exceed max width.
+pub(crate) fn combine_strs_with_missing_comments(
+ context: &RewriteContext<'_>,
+ prev_str: &str,
+ next_str: &str,
+ span: Span,
+ shape: Shape,
+ allow_extend: bool,
+) -> Option<String> {
+ trace!(
+ "combine_strs_with_missing_comments `{}` `{}` {:?} {:?}",
+ prev_str,
+ next_str,
+ span,
+ shape
+ );
+
+ let mut result =
+ String::with_capacity(prev_str.len() + next_str.len() + shape.indent.width() + 128);
+ result.push_str(prev_str);
+ let mut allow_one_line = !prev_str.contains('\n') && !next_str.contains('\n');
+ let first_sep = if prev_str.is_empty() || next_str.is_empty() {
+ ""
+ } else {
+ " "
+ };
+ let mut one_line_width =
+ last_line_width(prev_str) + first_line_width(next_str) + first_sep.len();
+
+ let config = context.config;
+ let indent = shape.indent;
+ let missing_comment = rewrite_missing_comment(span, shape, context)?;
+
+ if missing_comment.is_empty() {
+ if allow_extend && prev_str.len() + first_sep.len() + next_str.len() <= shape.width {
+ result.push_str(first_sep);
+ } else if !prev_str.is_empty() {
+ result.push_str(&indent.to_string_with_newline(config))
+ }
+ result.push_str(next_str);
+ return Some(result);
+ }
+
+ // We have a missing comment between the first expression and the second expression.
+
+ // Peek the the original source code and find out whether there is a newline between the first
+ // expression and the second expression or the missing comment. We will preserve the original
+ // layout whenever possible.
+ let original_snippet = context.snippet(span);
+ let prefer_same_line = if let Some(pos) = original_snippet.find('/') {
+ !original_snippet[..pos].contains('\n')
+ } else {
+ !original_snippet.contains('\n')
+ };
+
+ one_line_width -= first_sep.len();
+ let first_sep = if prev_str.is_empty() || missing_comment.is_empty() {
+ Cow::from("")
+ } else {
+ let one_line_width = last_line_width(prev_str) + first_line_width(&missing_comment) + 1;
+ if prefer_same_line && one_line_width <= shape.width {
+ Cow::from(" ")
+ } else {
+ indent.to_string_with_newline(config)
+ }
+ };
+ result.push_str(&first_sep);
+ result.push_str(&missing_comment);
+
+ let second_sep = if missing_comment.is_empty() || next_str.is_empty() {
+ Cow::from("")
+ } else if missing_comment.starts_with("//") {
+ indent.to_string_with_newline(config)
+ } else {
+ one_line_width += missing_comment.len() + first_sep.len() + 1;
+ allow_one_line &= !missing_comment.starts_with("//") && !missing_comment.contains('\n');
+ if prefer_same_line && allow_one_line && one_line_width <= shape.width {
+ Cow::from(" ")
+ } else {
+ indent.to_string_with_newline(config)
+ }
+ };
+ result.push_str(&second_sep);
+ result.push_str(next_str);
+
+ Some(result)
+}
+
+pub(crate) fn rewrite_doc_comment(orig: &str, shape: Shape, config: &Config) -> Option<String> {
+ identify_comment(orig, false, shape, config, true)
+}
+
+pub(crate) fn rewrite_comment(
+ orig: &str,
+ block_style: bool,
+ shape: Shape,
+ config: &Config,
+) -> Option<String> {
+ identify_comment(orig, block_style, shape, config, false)
+}
+
+fn identify_comment(
+ orig: &str,
+ block_style: bool,
+ shape: Shape,
+ config: &Config,
+ is_doc_comment: bool,
+) -> Option<String> {
+ let style = comment_style(orig, false);
+
+ // Computes the byte length of line taking into account a newline if the line is part of a
+ // paragraph.
+ fn compute_len(orig: &str, line: &str) -> usize {
+ if orig.len() > line.len() {
+ if orig.as_bytes()[line.len()] == b'\r' {
+ line.len() + 2
+ } else {
+ line.len() + 1
+ }
+ } else {
+ line.len()
+ }
+ }
+
+ // Get the first group of line comments having the same commenting style.
+ //
+ // Returns a tuple with:
+ // - a boolean indicating if there is a blank line
+ // - a number indicating the size of the first group of comments
+ fn consume_same_line_comments(
+ style: CommentStyle<'_>,
+ orig: &str,
+ line_start: &str,
+ ) -> (bool, usize) {
+ let mut first_group_ending = 0;
+ let mut hbl = false;
+
+ for line in orig.lines() {
+ let trimmed_line = line.trim_start();
+ if trimmed_line.is_empty() {
+ hbl = true;
+ break;
+ } else if trimmed_line.starts_with(line_start)
+ || comment_style(trimmed_line, false) == style
+ {
+ first_group_ending += compute_len(&orig[first_group_ending..], line);
+ } else {
+ break;
+ }
+ }
+ (hbl, first_group_ending)
+ }
+
+ let (has_bare_lines, first_group_ending) = match style {
+ CommentStyle::DoubleSlash | CommentStyle::TripleSlash | CommentStyle::Doc => {
+ let line_start = style.line_start().trim_start();
+ consume_same_line_comments(style, orig, line_start)
+ }
+ CommentStyle::Custom(opener) => {
+ let trimmed_opener = opener.trim_end();
+ consume_same_line_comments(style, orig, trimmed_opener)
+ }
+ // for a block comment, search for the closing symbol
+ CommentStyle::DoubleBullet | CommentStyle::SingleBullet | CommentStyle::Exclamation => {
+ let closer = style.closer().trim_start();
+ let mut count = orig.matches(closer).count();
+ let mut closing_symbol_offset = 0;
+ let mut hbl = false;
+ let mut first = true;
+ for line in orig.lines() {
+ closing_symbol_offset += compute_len(&orig[closing_symbol_offset..], line);
+ let mut trimmed_line = line.trim_start();
+ if !trimmed_line.starts_with('*')
+ && !trimmed_line.starts_with("//")
+ && !trimmed_line.starts_with("/*")
+ {
+ hbl = true;
+ }
+
+ // Remove opener from consideration when searching for closer
+ if first {
+ let opener = style.opener().trim_end();
+ trimmed_line = &trimmed_line[opener.len()..];
+ first = false;
+ }
+ if trimmed_line.ends_with(closer) {
+ count -= 1;
+ if count == 0 {
+ break;
+ }
+ }
+ }
+ (hbl, closing_symbol_offset)
+ }
+ };
+
+ let (first_group, rest) = orig.split_at(first_group_ending);
+ let rewritten_first_group =
+ if !config.normalize_comments() && has_bare_lines && style.is_block_comment() {
+ trim_left_preserve_layout(first_group, shape.indent, config)?
+ } else if !config.normalize_comments()
+ && !config.wrap_comments()
+ && !config.format_code_in_doc_comments()
+ {
+ light_rewrite_comment(first_group, shape.indent, config, is_doc_comment)
+ } else {
+ rewrite_comment_inner(
+ first_group,
+ block_style,
+ style,
+ shape,
+ config,
+ is_doc_comment || style.is_doc_comment(),
+ )?
+ };
+ if rest.is_empty() {
+ Some(rewritten_first_group)
+ } else {
+ identify_comment(
+ rest.trim_start(),
+ block_style,
+ shape,
+ config,
+ is_doc_comment,
+ )
+ .map(|rest_str| {
+ format!(
+ "{}\n{}{}{}",
+ rewritten_first_group,
+ // insert back the blank line
+ if has_bare_lines && style.is_line_comment() {
+ "\n"
+ } else {
+ ""
+ },
+ shape.indent.to_string(config),
+ rest_str
+ )
+ })
+ }
+}
+
+/// Attributes for code blocks in rustdoc.
+/// See https://doc.rust-lang.org/rustdoc/print.html#attributes
+enum CodeBlockAttribute {
+ Rust,
+ Ignore,
+ Text,
+ ShouldPanic,
+ NoRun,
+ CompileFail,
+}
+
+impl CodeBlockAttribute {
+ fn new(attribute: &str) -> CodeBlockAttribute {
+ match attribute {
+ "rust" | "" => CodeBlockAttribute::Rust,
+ "ignore" => CodeBlockAttribute::Ignore,
+ "text" => CodeBlockAttribute::Text,
+ "should_panic" => CodeBlockAttribute::ShouldPanic,
+ "no_run" => CodeBlockAttribute::NoRun,
+ "compile_fail" => CodeBlockAttribute::CompileFail,
+ _ => CodeBlockAttribute::Text,
+ }
+ }
+}
+
+/// Block that is formatted as an item.
+///
+/// An item starts with either a star `*` or a dash `-`. Different level of indentation are
+/// handled by shrinking the shape accordingly.
+struct ItemizedBlock {
+ /// the lines that are identified as part of an itemized block
+ lines: Vec<String>,
+ /// the number of whitespaces up to the item sigil
+ indent: usize,
+ /// the string that marks the start of an item
+ opener: String,
+ /// sequence of whitespaces to prefix new lines that are part of the item
+ line_start: String,
+}
+
+impl ItemizedBlock {
+ /// Returns `true` if the line is formatted as an item
+ fn is_itemized_line(line: &str) -> bool {
+ let trimmed = line.trim_start();
+ trimmed.starts_with("* ") || trimmed.starts_with("- ")
+ }
+
+ /// Creates a new ItemizedBlock described with the given line.
+ /// The `is_itemized_line` needs to be called first.
+ fn new(line: &str) -> ItemizedBlock {
+ let space_to_sigil = line.chars().take_while(|c| c.is_whitespace()).count();
+ let indent = space_to_sigil + 2;
+ ItemizedBlock {
+ lines: vec![line[indent..].to_string()],
+ indent,
+ opener: line[..indent].to_string(),
+ line_start: " ".repeat(indent),
+ }
+ }
+
+ /// Returns a `StringFormat` used for formatting the content of an item.
+ fn create_string_format<'a>(&'a self, fmt: &'a StringFormat<'_>) -> StringFormat<'a> {
+ StringFormat {
+ opener: "",
+ closer: "",
+ line_start: "",
+ line_end: "",
+ shape: Shape::legacy(fmt.shape.width.saturating_sub(self.indent), Indent::empty()),
+ trim_end: true,
+ config: fmt.config,
+ }
+ }
+
+ /// Returns `true` if the line is part of the current itemized block.
+ /// If it is, then it is added to the internal lines list.
+ fn add_line(&mut self, line: &str) -> bool {
+ if !ItemizedBlock::is_itemized_line(line)
+ && self.indent <= line.chars().take_while(|c| c.is_whitespace()).count()
+ {
+ self.lines.push(line.to_string());
+ return true;
+ }
+ false
+ }
+
+ /// Returns the block as a string, with each line trimmed at the start.
+ fn trimmed_block_as_string(&self) -> String {
+ self.lines
+ .iter()
+ .map(|line| format!("{} ", line.trim_start()))
+ .collect::<String>()
+ }
+
+ /// Returns the block as a string under its original form.
+ fn original_block_as_string(&self) -> String {
+ self.lines.join("\n")
+ }
+}
+
+struct CommentRewrite<'a> {
+ result: String,
+ code_block_buffer: String,
+ is_prev_line_multi_line: bool,
+ code_block_attr: Option<CodeBlockAttribute>,
+ item_block: Option<ItemizedBlock>,
+ comment_line_separator: String,
+ indent_str: String,
+ max_width: usize,
+ fmt_indent: Indent,
+ fmt: StringFormat<'a>,
+
+ opener: String,
+ closer: String,
+ line_start: String,
+}
+
+impl<'a> CommentRewrite<'a> {
+ fn new(
+ orig: &'a str,
+ block_style: bool,
+ shape: Shape,
+ config: &'a Config,
+ ) -> CommentRewrite<'a> {
+ let (opener, closer, line_start) = if block_style {
+ CommentStyle::SingleBullet.to_str_tuplet()
+ } else {
+ comment_style(orig, config.normalize_comments()).to_str_tuplet()
+ };
+
+ let max_width = shape
+ .width
+ .checked_sub(closer.len() + opener.len())
+ .unwrap_or(1);
+ let indent_str = shape.indent.to_string_with_newline(config).to_string();
+
+ let mut cr = CommentRewrite {
+ result: String::with_capacity(orig.len() * 2),
+ code_block_buffer: String::with_capacity(128),
+ is_prev_line_multi_line: false,
+ code_block_attr: None,
+ item_block: None,
+ comment_line_separator: format!("{}{}", indent_str, line_start),
+ max_width,
+ indent_str,
+ fmt_indent: shape.indent,
+
+ fmt: StringFormat {
+ opener: "",
+ closer: "",
+ line_start,
+ line_end: "",
+ shape: Shape::legacy(max_width, shape.indent),
+ trim_end: true,
+ config,
+ },
+
+ opener: opener.to_owned(),
+ closer: closer.to_owned(),
+ line_start: line_start.to_owned(),
+ };
+ cr.result.push_str(opener);
+ cr
+ }
+
+ fn join_block(s: &str, sep: &str) -> String {
+ let mut result = String::with_capacity(s.len() + 128);
+ let mut iter = s.lines().peekable();
+ while let Some(line) = iter.next() {
+ result.push_str(line);
+ result.push_str(match iter.peek() {
+ Some(next_line) if next_line.is_empty() => sep.trim_end(),
+ Some(..) => &sep,
+ None => "",
+ });
+ }
+ result
+ }
+
+ fn finish(mut self) -> String {
+ if !self.code_block_buffer.is_empty() {
+ // There is a code block that is not properly enclosed by backticks.
+ // We will leave them untouched.
+ self.result.push_str(&self.comment_line_separator);
+ self.result.push_str(&Self::join_block(
+ &trim_custom_comment_prefix(&self.code_block_buffer),
+ &self.comment_line_separator,
+ ));
+ }
+
+ if let Some(ref ib) = self.item_block {
+ // the last few lines are part of an itemized block
+ self.fmt.shape = Shape::legacy(self.max_width, self.fmt_indent);
+ let item_fmt = ib.create_string_format(&self.fmt);
+ self.result.push_str(&self.comment_line_separator);
+ self.result.push_str(&ib.opener);
+ match rewrite_string(
+ &ib.trimmed_block_as_string(),
+ &item_fmt,
+ self.max_width.saturating_sub(ib.indent),
+ ) {
+ Some(s) => self.result.push_str(&Self::join_block(
+ &s,
+ &format!("{}{}", self.comment_line_separator, ib.line_start),
+ )),
+ None => self.result.push_str(&Self::join_block(
+ &ib.original_block_as_string(),
+ &self.comment_line_separator,
+ )),
+ };
+ }
+
+ self.result.push_str(&self.closer);
+ if self.result.ends_with(&self.opener) && self.opener.ends_with(' ') {
+ // Trailing space.
+ self.result.pop();
+ }
+
+ self.result
+ }
+
+ fn handle_line(
+ &mut self,
+ orig: &'a str,
+ i: usize,
+ line: &'a str,
+ has_leading_whitespace: bool,
+ ) -> bool {
+ let is_last = i == count_newlines(orig);
+
+ if let Some(ref mut ib) = self.item_block {
+ if ib.add_line(&line) {
+ return false;
+ }
+ self.is_prev_line_multi_line = false;
+ self.fmt.shape = Shape::legacy(self.max_width, self.fmt_indent);
+ let item_fmt = ib.create_string_format(&self.fmt);
+ self.result.push_str(&self.comment_line_separator);
+ self.result.push_str(&ib.opener);
+ match rewrite_string(
+ &ib.trimmed_block_as_string(),
+ &item_fmt,
+ self.max_width.saturating_sub(ib.indent),
+ ) {
+ Some(s) => self.result.push_str(&Self::join_block(
+ &s,
+ &format!("{}{}", self.comment_line_separator, ib.line_start),
+ )),
+ None => self.result.push_str(&Self::join_block(
+ &ib.original_block_as_string(),
+ &self.comment_line_separator,
+ )),
+ };
+ } else if self.code_block_attr.is_some() {
+ if line.starts_with("```") {
+ let code_block = match self.code_block_attr.as_ref().unwrap() {
+ CodeBlockAttribute::Ignore | CodeBlockAttribute::Text => {
+ trim_custom_comment_prefix(&self.code_block_buffer)
+ }
+ _ if self.code_block_buffer.is_empty() => String::new(),
+ _ => {
+ let mut config = self.fmt.config.clone();
+ config.set().wrap_comments(false);
+ if config.format_code_in_doc_comments() {
+ if let Some(s) =
+ crate::format_code_block(&self.code_block_buffer, &config, false)
+ {
+ trim_custom_comment_prefix(&s.snippet)
+ } else {
+ trim_custom_comment_prefix(&self.code_block_buffer)
+ }
+ } else {
+ trim_custom_comment_prefix(&self.code_block_buffer)
+ }
+ }
+ };
+ if !code_block.is_empty() {
+ self.result.push_str(&self.comment_line_separator);
+ self.result
+ .push_str(&Self::join_block(&code_block, &self.comment_line_separator));
+ }
+ self.code_block_buffer.clear();
+ self.result.push_str(&self.comment_line_separator);
+ self.result.push_str(line);
+ self.code_block_attr = None;
+ } else {
+ self.code_block_buffer
+ .push_str(&hide_sharp_behind_comment(line));
+ self.code_block_buffer.push('\n');
+ }
+ return false;
+ }
+
+ self.code_block_attr = None;
+ self.item_block = None;
+ if line.starts_with("```") {
+ self.code_block_attr = Some(CodeBlockAttribute::new(&line[3..]))
+ } else if self.fmt.config.wrap_comments() && ItemizedBlock::is_itemized_line(&line) {
+ let ib = ItemizedBlock::new(&line);
+ self.item_block = Some(ib);
+ return false;
+ }
+
+ if self.result == self.opener {
+ let force_leading_whitespace = &self.opener == "/* " && count_newlines(orig) == 0;
+ if !has_leading_whitespace && !force_leading_whitespace && self.result.ends_with(' ') {
+ self.result.pop();
+ }
+ if line.is_empty() {
+ return false;
+ }
+ } else if self.is_prev_line_multi_line && !line.is_empty() {
+ self.result.push(' ')
+ } else if is_last && line.is_empty() {
+ // trailing blank lines are unwanted
+ if !self.closer.is_empty() {
+ self.result.push_str(&self.indent_str);
+ }
+ return true;
+ } else {
+ self.result.push_str(&self.comment_line_separator);
+ if !has_leading_whitespace && self.result.ends_with(' ') {
+ self.result.pop();
+ }
+ }
+
+ if self.fmt.config.wrap_comments()
+ && unicode_str_width(line) > self.fmt.shape.width
+ && !has_url(line)
+ {
+ match rewrite_string(line, &self.fmt, self.max_width) {
+ Some(ref s) => {
+ self.is_prev_line_multi_line = s.contains('\n');
+ self.result.push_str(s);
+ }
+ None if self.is_prev_line_multi_line => {
+ // We failed to put the current `line` next to the previous `line`.
+ // Remove the trailing space, then start rewrite on the next line.
+ self.result.pop();
+ self.result.push_str(&self.comment_line_separator);
+ self.fmt.shape = Shape::legacy(self.max_width, self.fmt_indent);
+ match rewrite_string(line, &self.fmt, self.max_width) {
+ Some(ref s) => {
+ self.is_prev_line_multi_line = s.contains('\n');
+ self.result.push_str(s);
+ }
+ None => {
+ self.is_prev_line_multi_line = false;
+ self.result.push_str(line);
+ }
+ }
+ }
+ None => {
+ self.is_prev_line_multi_line = false;
+ self.result.push_str(line);
+ }
+ }
+
+ self.fmt.shape = if self.is_prev_line_multi_line {
+ // 1 = " "
+ let offset = 1 + last_line_width(&self.result) - self.line_start.len();
+ Shape {
+ width: self.max_width.saturating_sub(offset),
+ indent: self.fmt_indent,
+ offset: self.fmt.shape.offset + offset,
+ }
+ } else {
+ Shape::legacy(self.max_width, self.fmt_indent)
+ };
+ } else {
+ if line.is_empty() && self.result.ends_with(' ') && !is_last {
+ // Remove space if this is an empty comment or a doc comment.
+ self.result.pop();
+ }
+ self.result.push_str(line);
+ self.fmt.shape = Shape::legacy(self.max_width, self.fmt_indent);
+ self.is_prev_line_multi_line = false;
+ }
+
+ false
+ }
+}
+
+fn rewrite_comment_inner(
+ orig: &str,
+ block_style: bool,
+ style: CommentStyle<'_>,
+ shape: Shape,
+ config: &Config,
+ is_doc_comment: bool,
+) -> Option<String> {
+ let mut rewriter = CommentRewrite::new(orig, block_style, shape, config);
+
+ let line_breaks = count_newlines(orig.trim_end());
+ let lines = orig
+ .lines()
+ .enumerate()
+ .map(|(i, mut line)| {
+ line = trim_end_unless_two_whitespaces(line.trim_start(), is_doc_comment);
+ // Drop old closer.
+ if i == line_breaks && line.ends_with("*/") && !line.starts_with("//") {
+ line = line[..(line.len() - 2)].trim_end();
+ }
+
+ line
+ })
+ .map(|s| left_trim_comment_line(s, &style))
+ .map(|(line, has_leading_whitespace)| {
+ if orig.starts_with("/*") && line_breaks == 0 {
+ (
+ line.trim_start(),
+ has_leading_whitespace || config.normalize_comments(),
+ )
+ } else {
+ (line, has_leading_whitespace || config.normalize_comments())
+ }
+ });
+
+ for (i, (line, has_leading_whitespace)) in lines.enumerate() {
+ if rewriter.handle_line(orig, i, line, has_leading_whitespace) {
+ break;
+ }
+ }
+
+ Some(rewriter.finish())
+}
+
+const RUSTFMT_CUSTOM_COMMENT_PREFIX: &str = "//#### ";
+
+fn hide_sharp_behind_comment(s: &str) -> Cow<'_, str> {
+ let s_trimmed = s.trim();
+ if s_trimmed.starts_with("# ") || s_trimmed == "#" {
+ Cow::from(format!("{}{}", RUSTFMT_CUSTOM_COMMENT_PREFIX, s))
+ } else {
+ Cow::from(s)
+ }
+}
+
+fn trim_custom_comment_prefix(s: &str) -> String {
+ s.lines()
+ .map(|line| {
+ let left_trimmed = line.trim_start();
+ if left_trimmed.starts_with(RUSTFMT_CUSTOM_COMMENT_PREFIX) {
+ left_trimmed.trim_start_matches(RUSTFMT_CUSTOM_COMMENT_PREFIX)
+ } else {
+ line
+ }
+ })
+ .collect::<Vec<_>>()
+ .join("\n")
+}
+
+/// Returns `true` if the given string MAY include URLs or alike.
+fn has_url(s: &str) -> bool {
+ // This function may return false positive, but should get its job done in most cases.
+ s.contains("https://") || s.contains("http://") || s.contains("ftp://") || s.contains("file://")
+}
+
+/// Given the span, rewrite the missing comment inside it if available.
+/// Note that the given span must only include comments (or leading/trailing whitespaces).
+pub(crate) fn rewrite_missing_comment(
+ span: Span,
+ shape: Shape,
+ context: &RewriteContext<'_>,
+) -> Option<String> {
+ let missing_snippet = context.snippet(span);
+ let trimmed_snippet = missing_snippet.trim();
+ // check the span starts with a comment
+ let pos = trimmed_snippet.find('/');
+ if !trimmed_snippet.is_empty() && pos.is_some() {
+ rewrite_comment(trimmed_snippet, false, shape, context.config)
+ } else {
+ Some(String::new())
+ }
+}
+
+/// Recover the missing comments in the specified span, if available.
+/// The layout of the comments will be preserved as long as it does not break the code
+/// and its total width does not exceed the max width.
+pub(crate) fn recover_missing_comment_in_span(
+ span: Span,
+ shape: Shape,
+ context: &RewriteContext<'_>,
+ used_width: usize,
+) -> Option<String> {
+ let missing_comment = rewrite_missing_comment(span, shape, context)?;
+ if missing_comment.is_empty() {
+ Some(String::new())
+ } else {
+ let missing_snippet = context.snippet(span);
+ let pos = missing_snippet.find('/')?;
+ // 1 = ` `
+ let total_width = missing_comment.len() + used_width + 1;
+ let force_new_line_before_comment =
+ missing_snippet[..pos].contains('\n') || total_width > context.config.max_width();
+ let sep = if force_new_line_before_comment {
+ shape.indent.to_string_with_newline(context.config)
+ } else {
+ Cow::from(" ")
+ };
+ Some(format!("{}{}", sep, missing_comment))
+ }
+}
+
+/// Trim trailing whitespaces unless they consist of two or more whitespaces.
+fn trim_end_unless_two_whitespaces(s: &str, is_doc_comment: bool) -> &str {
+ if is_doc_comment && s.ends_with(" ") {
+ s
+ } else {
+ s.trim_end()
+ }
+}
+
+/// Trims whitespace and aligns to indent, but otherwise does not change comments.
+fn light_rewrite_comment(
+ orig: &str,
+ offset: Indent,
+ config: &Config,
+ is_doc_comment: bool,
+) -> String {
+ let lines: Vec<&str> = orig
+ .lines()
+ .map(|l| {
+ // This is basically just l.trim(), but in the case that a line starts
+ // with `*` we want to leave one space before it, so it aligns with the
+ // `*` in `/*`.
+ let first_non_whitespace = l.find(|c| !char::is_whitespace(c));
+ let left_trimmed = if let Some(fnw) = first_non_whitespace {
+ if l.as_bytes()[fnw] == b'*' && fnw > 0 {
+ &l[fnw - 1..]
+ } else {
+ &l[fnw..]
+ }
+ } else {
+ ""
+ };
+ // Preserve markdown's double-space line break syntax in doc comment.
+ trim_end_unless_two_whitespaces(left_trimmed, is_doc_comment)
+ })
+ .collect();
+ lines.join(&format!("\n{}", offset.to_string(config)))
+}
+
+/// Trims comment characters and possibly a single space from the left of a string.
+/// Does not trim all whitespace. If a single space is trimmed from the left of the string,
+/// this function returns true.
+fn left_trim_comment_line<'a>(line: &'a str, style: &CommentStyle<'_>) -> (&'a str, bool) {
+ if line.starts_with("//! ")
+ || line.starts_with("/// ")
+ || line.starts_with("/*! ")
+ || line.starts_with("/** ")
+ {
+ (&line[4..], true)
+ } else if let CommentStyle::Custom(opener) = *style {
+ if line.starts_with(opener) {
+ (&line[opener.len()..], true)
+ } else {
+ (&line[opener.trim_end().len()..], false)
+ }
+ } else if line.starts_with("/* ")
+ || line.starts_with("// ")
+ || line.starts_with("//!")
+ || line.starts_with("///")
+ || line.starts_with("** ")
+ || line.starts_with("/*!")
+ || (line.starts_with("/**") && !line.starts_with("/**/"))
+ {
+ (&line[3..], line.chars().nth(2).unwrap() == ' ')
+ } else if line.starts_with("/*")
+ || line.starts_with("* ")
+ || line.starts_with("//")
+ || line.starts_with("**")
+ {
+ (&line[2..], line.chars().nth(1).unwrap() == ' ')
+ } else if line.starts_with('*') {
+ (&line[1..], false)
+ } else {
+ (line, line.starts_with(' '))
+ }
+}
+
+pub(crate) trait FindUncommented {
+ fn find_uncommented(&self, pat: &str) -> Option<usize>;
+}
+
+impl FindUncommented for str {
+ fn find_uncommented(&self, pat: &str) -> Option<usize> {
+ let mut needle_iter = pat.chars();
+ for (kind, (i, b)) in CharClasses::new(self.char_indices()) {
+ match needle_iter.next() {
+ None => {
+ return Some(i - pat.len());
+ }
+ Some(c) => match kind {
+ FullCodeCharKind::Normal | FullCodeCharKind::InString if b == c => {}
+ _ => {
+ needle_iter = pat.chars();
+ }
+ },
+ }
+ }
+
+ // Handle case where the pattern is a suffix of the search string
+ match needle_iter.next() {
+ Some(_) => None,
+ None => Some(self.len() - pat.len()),
+ }
+ }
+}
+
+// Returns the first byte position after the first comment. The given string
+// is expected to be prefixed by a comment, including delimiters.
+// Good: `/* /* inner */ outer */ code();`
+// Bad: `code(); // hello\n world!`
+pub(crate) fn find_comment_end(s: &str) -> Option<usize> {
+ let mut iter = CharClasses::new(s.char_indices());
+ for (kind, (i, _c)) in &mut iter {
+ if kind == FullCodeCharKind::Normal || kind == FullCodeCharKind::InString {
+ return Some(i);
+ }
+ }
+
+ // Handle case where the comment ends at the end of `s`.
+ if iter.status == CharClassesStatus::Normal {
+ Some(s.len())
+ } else {
+ None
+ }
+}
+
+/// Returns `true` if text contains any comment.
+pub(crate) fn contains_comment(text: &str) -> bool {
+ CharClasses::new(text.chars()).any(|(kind, _)| kind.is_comment())
+}
+
+pub(crate) struct CharClasses<T>
+where
+ T: Iterator,
+ T::Item: RichChar,
+{
+ base: MultiPeek<T>,
+ status: CharClassesStatus,
+}
+
+pub(crate) trait RichChar {
+ fn get_char(&self) -> char;
+}
+
+impl RichChar for char {
+ fn get_char(&self) -> char {
+ *self
+ }
+}
+
+impl RichChar for (usize, char) {
+ fn get_char(&self) -> char {
+ self.1
+ }
+}
+
+#[derive(PartialEq, Eq, Debug, Clone, Copy)]
+enum CharClassesStatus {
+ Normal,
+ /// Character is within a string
+ LitString,
+ LitStringEscape,
+ /// Character is within a raw string
+ LitRawString(u32),
+ RawStringPrefix(u32),
+ RawStringSuffix(u32),
+ LitChar,
+ LitCharEscape,
+ /// Character inside a block comment, with the integer indicating the nesting deepness of the
+ /// comment
+ BlockComment(u32),
+ /// Character inside a block-commented string, with the integer indicating the nesting deepness
+ /// of the comment
+ StringInBlockComment(u32),
+ /// Status when the '/' has been consumed, but not yet the '*', deepness is
+ /// the new deepness (after the comment opening).
+ BlockCommentOpening(u32),
+ /// Status when the '*' has been consumed, but not yet the '/', deepness is
+ /// the new deepness (after the comment closing).
+ BlockCommentClosing(u32),
+ /// Character is within a line comment
+ LineComment,
+}
+
+/// Distinguish between functional part of code and comments
+#[derive(PartialEq, Eq, Debug, Clone, Copy)]
+pub(crate) enum CodeCharKind {
+ Normal,
+ Comment,
+}
+
+/// Distinguish between functional part of code and comments,
+/// describing opening and closing of comments for ease when chunking
+/// code from tagged characters
+#[derive(PartialEq, Eq, Debug, Clone, Copy)]
+pub(crate) enum FullCodeCharKind {
+ Normal,
+ /// The first character of a comment, there is only one for a comment (always '/')
+ StartComment,
+ /// Any character inside a comment including the second character of comment
+ /// marks ("//", "/*")
+ InComment,
+ /// Last character of a comment, '\n' for a line comment, '/' for a block comment.
+ EndComment,
+ /// Start of a mutlitine string inside a comment
+ StartStringCommented,
+ /// End of a mutlitine string inside a comment
+ EndStringCommented,
+ /// Inside a commented string
+ InStringCommented,
+ /// Start of a mutlitine string
+ StartString,
+ /// End of a mutlitine string
+ EndString,
+ /// Inside a string.
+ InString,
+}
+
+impl FullCodeCharKind {
+ pub(crate) fn is_comment(self) -> bool {
+ match self {
+ FullCodeCharKind::StartComment
+ | FullCodeCharKind::InComment
+ | FullCodeCharKind::EndComment
+ | FullCodeCharKind::StartStringCommented
+ | FullCodeCharKind::InStringCommented
+ | FullCodeCharKind::EndStringCommented => true,
+ _ => false,
+ }
+ }
+
+ /// Returns true if the character is inside a comment
+ pub(crate) fn inside_comment(self) -> bool {
+ match self {
+ FullCodeCharKind::InComment
+ | FullCodeCharKind::StartStringCommented
+ | FullCodeCharKind::InStringCommented
+ | FullCodeCharKind::EndStringCommented => true,
+ _ => false,
+ }
+ }
+
+ pub(crate) fn is_string(self) -> bool {
+ self == FullCodeCharKind::InString || self == FullCodeCharKind::StartString
+ }
+
+ /// Returns true if the character is within a commented string
+ pub(crate) fn is_commented_string(self) -> bool {
+ self == FullCodeCharKind::InStringCommented
+ || self == FullCodeCharKind::StartStringCommented
+ }
+
+ fn to_codecharkind(self) -> CodeCharKind {
+ if self.is_comment() {
+ CodeCharKind::Comment
+ } else {
+ CodeCharKind::Normal
+ }
+ }
+}
+
+impl<T> CharClasses<T>
+where
+ T: Iterator,
+ T::Item: RichChar,
+{
+ pub(crate) fn new(base: T) -> CharClasses<T> {
+ CharClasses {
+ base: multipeek(base),
+ status: CharClassesStatus::Normal,
+ }
+ }
+}
+
+fn is_raw_string_suffix<T>(iter: &mut MultiPeek<T>, count: u32) -> bool
+where
+ T: Iterator,
+ T::Item: RichChar,
+{
+ for _ in 0..count {
+ match iter.peek() {
+ Some(c) if c.get_char() == '#' => continue,
+ _ => return false,
+ }
+ }
+ true
+}
+
+impl<T> Iterator for CharClasses<T>
+where
+ T: Iterator,
+ T::Item: RichChar,
+{
+ type Item = (FullCodeCharKind, T::Item);
+
+ fn next(&mut self) -> Option<(FullCodeCharKind, T::Item)> {
+ let item = self.base.next()?;
+ let chr = item.get_char();
+ let mut char_kind = FullCodeCharKind::Normal;
+ self.status = match self.status {
+ CharClassesStatus::LitRawString(sharps) => {
+ char_kind = FullCodeCharKind::InString;
+ match chr {
+ '"' => {
+ if sharps == 0 {
+ char_kind = FullCodeCharKind::Normal;
+ CharClassesStatus::Normal
+ } else if is_raw_string_suffix(&mut self.base, sharps) {
+ CharClassesStatus::RawStringSuffix(sharps)
+ } else {
+ CharClassesStatus::LitRawString(sharps)
+ }
+ }
+ _ => CharClassesStatus::LitRawString(sharps),
+ }
+ }
+ CharClassesStatus::RawStringPrefix(sharps) => {
+ char_kind = FullCodeCharKind::InString;
+ match chr {
+ '#' => CharClassesStatus::RawStringPrefix(sharps + 1),
+ '"' => CharClassesStatus::LitRawString(sharps),
+ _ => CharClassesStatus::Normal, // Unreachable.
+ }
+ }
+ CharClassesStatus::RawStringSuffix(sharps) => {
+ match chr {
+ '#' => {
+ if sharps == 1 {
+ CharClassesStatus::Normal
+ } else {
+ char_kind = FullCodeCharKind::InString;
+ CharClassesStatus::RawStringSuffix(sharps - 1)
+ }
+ }
+ _ => CharClassesStatus::Normal, // Unreachable
+ }
+ }
+ CharClassesStatus::LitString => {
+ char_kind = FullCodeCharKind::InString;
+ match chr {
+ '"' => CharClassesStatus::Normal,
+ '\\' => CharClassesStatus::LitStringEscape,
+ _ => CharClassesStatus::LitString,
+ }
+ }
+ CharClassesStatus::LitStringEscape => {
+ char_kind = FullCodeCharKind::InString;
+ CharClassesStatus::LitString
+ }
+ CharClassesStatus::LitChar => match chr {
+ '\\' => CharClassesStatus::LitCharEscape,
+ '\'' => CharClassesStatus::Normal,
+ _ => CharClassesStatus::LitChar,
+ },
+ CharClassesStatus::LitCharEscape => CharClassesStatus::LitChar,
+ CharClassesStatus::Normal => match chr {
+ 'r' => match self.base.peek().map(RichChar::get_char) {
+ Some('#') | Some('"') => {
+ char_kind = FullCodeCharKind::InString;
+ CharClassesStatus::RawStringPrefix(0)
+ }
+ _ => CharClassesStatus::Normal,
+ },
+ '"' => {
+ char_kind = FullCodeCharKind::InString;
+ CharClassesStatus::LitString
+ }
+ '\'' => {
+ // HACK: Work around mut borrow.
+ match self.base.peek() {
+ Some(next) if next.get_char() == '\\' => {
+ self.status = CharClassesStatus::LitChar;
+ return Some((char_kind, item));
+ }
+ _ => (),
+ }
+
+ match self.base.peek() {
+ Some(next) if next.get_char() == '\'' => CharClassesStatus::LitChar,
+ _ => CharClassesStatus::Normal,
+ }
+ }
+ '/' => match self.base.peek() {
+ Some(next) if next.get_char() == '*' => {
+ self.status = CharClassesStatus::BlockCommentOpening(1);
+ return Some((FullCodeCharKind::StartComment, item));
+ }
+ Some(next) if next.get_char() == '/' => {
+ self.status = CharClassesStatus::LineComment;
+ return Some((FullCodeCharKind::StartComment, item));
+ }
+ _ => CharClassesStatus::Normal,
+ },
+ _ => CharClassesStatus::Normal,
+ },
+ CharClassesStatus::StringInBlockComment(deepness) => {
+ char_kind = FullCodeCharKind::InStringCommented;
+ if chr == '"' {
+ CharClassesStatus::BlockComment(deepness)
+ } else {
+ CharClassesStatus::StringInBlockComment(deepness)
+ }
+ }
+ CharClassesStatus::BlockComment(deepness) => {
+ assert_ne!(deepness, 0);
+ char_kind = FullCodeCharKind::InComment;
+ match self.base.peek() {
+ Some(next) if next.get_char() == '/' && chr == '*' => {
+ CharClassesStatus::BlockCommentClosing(deepness - 1)
+ }
+ Some(next) if next.get_char() == '*' && chr == '/' => {
+ CharClassesStatus::BlockCommentOpening(deepness + 1)
+ }
+ _ if chr == '"' => CharClassesStatus::StringInBlockComment(deepness),
+ _ => self.status,
+ }
+ }
+ CharClassesStatus::BlockCommentOpening(deepness) => {
+ assert_eq!(chr, '*');
+ self.status = CharClassesStatus::BlockComment(deepness);
+ return Some((FullCodeCharKind::InComment, item));
+ }
+ CharClassesStatus::BlockCommentClosing(deepness) => {
+ assert_eq!(chr, '/');
+ if deepness == 0 {
+ self.status = CharClassesStatus::Normal;
+ return Some((FullCodeCharKind::EndComment, item));
+ } else {
+ self.status = CharClassesStatus::BlockComment(deepness);
+ return Some((FullCodeCharKind::InComment, item));
+ }
+ }
+ CharClassesStatus::LineComment => match chr {
+ '\n' => {
+ self.status = CharClassesStatus::Normal;
+ return Some((FullCodeCharKind::EndComment, item));
+ }
+ _ => {
+ self.status = CharClassesStatus::LineComment;
+ return Some((FullCodeCharKind::InComment, item));
+ }
+ },
+ };
+ Some((char_kind, item))
+ }
+}
+
+/// An iterator over the lines of a string, paired with the char kind at the
+/// end of the line.
+pub(crate) struct LineClasses<'a> {
+ base: iter::Peekable<CharClasses<std::str::Chars<'a>>>,
+ kind: FullCodeCharKind,
+}
+
+impl<'a> LineClasses<'a> {
+ pub(crate) fn new(s: &'a str) -> Self {
+ LineClasses {
+ base: CharClasses::new(s.chars()).peekable(),
+ kind: FullCodeCharKind::Normal,
+ }
+ }
+}
+
+impl<'a> Iterator for LineClasses<'a> {
+ type Item = (FullCodeCharKind, String);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.base.peek()?;
+
+ let mut line = String::new();
+
+ let start_kind = match self.base.peek() {
+ Some((kind, _)) => *kind,
+ None => unreachable!(),
+ };
+
+ while let Some((kind, c)) = self.base.next() {
+ // needed to set the kind of the ending character on the last line
+ self.kind = kind;
+ if c == '\n' {
+ self.kind = match (start_kind, kind) {
+ (FullCodeCharKind::Normal, FullCodeCharKind::InString) => {
+ FullCodeCharKind::StartString
+ }
+ (FullCodeCharKind::InString, FullCodeCharKind::Normal) => {
+ FullCodeCharKind::EndString
+ }
+ (FullCodeCharKind::InComment, FullCodeCharKind::InStringCommented) => {
+ FullCodeCharKind::StartStringCommented
+ }
+ (FullCodeCharKind::InStringCommented, FullCodeCharKind::InComment) => {
+ FullCodeCharKind::EndStringCommented
+ }
+ _ => kind,
+ };
+ break;
+ }
+ line.push(c);
+ }
+
+ // Workaround for CRLF newline.
+ if line.ends_with('\r') {
+ line.pop();
+ }
+
+ Some((self.kind, line))
+ }
+}
+
+/// Iterator over functional and commented parts of a string. Any part of a string is either
+/// functional code, either *one* block comment, either *one* line comment. Whitespace between
+/// comments is functional code. Line comments contain their ending newlines.
+struct UngroupedCommentCodeSlices<'a> {
+ slice: &'a str,
+ iter: iter::Peekable<CharClasses<std::str::CharIndices<'a>>>,
+}
+
+impl<'a> UngroupedCommentCodeSlices<'a> {
+ fn new(code: &'a str) -> UngroupedCommentCodeSlices<'a> {
+ UngroupedCommentCodeSlices {
+ slice: code,
+ iter: CharClasses::new(code.char_indices()).peekable(),
+ }
+ }
+}
+
+impl<'a> Iterator for UngroupedCommentCodeSlices<'a> {
+ type Item = (CodeCharKind, usize, &'a str);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ let (kind, (start_idx, _)) = self.iter.next()?;
+ match kind {
+ FullCodeCharKind::Normal | FullCodeCharKind::InString => {
+ // Consume all the Normal code
+ while let Some(&(char_kind, _)) = self.iter.peek() {
+ if char_kind.is_comment() {
+ break;
+ }
+ let _ = self.iter.next();
+ }
+ }
+ FullCodeCharKind::StartComment => {
+ // Consume the whole comment
+ loop {
+ match self.iter.next() {
+ Some((kind, ..)) if kind.inside_comment() => continue,
+ _ => break,
+ }
+ }
+ }
+ _ => panic!(),
+ }
+ let slice = match self.iter.peek() {
+ Some(&(_, (end_idx, _))) => &self.slice[start_idx..end_idx],
+ None => &self.slice[start_idx..],
+ };
+ Some((
+ if kind.is_comment() {
+ CodeCharKind::Comment
+ } else {
+ CodeCharKind::Normal
+ },
+ start_idx,
+ slice,
+ ))
+ }
+}
+
+/// Iterator over an alternating sequence of functional and commented parts of
+/// a string. The first item is always a, possibly zero length, subslice of
+/// functional text. Line style comments contain their ending newlines.
+pub(crate) struct CommentCodeSlices<'a> {
+ slice: &'a str,
+ last_slice_kind: CodeCharKind,
+ last_slice_end: usize,
+}
+
+impl<'a> CommentCodeSlices<'a> {
+ pub(crate) fn new(slice: &'a str) -> CommentCodeSlices<'a> {
+ CommentCodeSlices {
+ slice,
+ last_slice_kind: CodeCharKind::Comment,
+ last_slice_end: 0,
+ }
+ }
+}
+
+impl<'a> Iterator for CommentCodeSlices<'a> {
+ type Item = (CodeCharKind, usize, &'a str);
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.last_slice_end == self.slice.len() {
+ return None;
+ }
+
+ let mut sub_slice_end = self.last_slice_end;
+ let mut first_whitespace = None;
+ let subslice = &self.slice[self.last_slice_end..];
+ let mut iter = CharClasses::new(subslice.char_indices());
+
+ for (kind, (i, c)) in &mut iter {
+ let is_comment_connector = self.last_slice_kind == CodeCharKind::Normal
+ && &subslice[..2] == "//"
+ && [' ', '\t'].contains(&c);
+
+ if is_comment_connector && first_whitespace.is_none() {
+ first_whitespace = Some(i);
+ }
+
+ if kind.to_codecharkind() == self.last_slice_kind && !is_comment_connector {
+ let last_index = match first_whitespace {
+ Some(j) => j,
+ None => i,
+ };
+ sub_slice_end = self.last_slice_end + last_index;
+ break;
+ }
+
+ if !is_comment_connector {
+ first_whitespace = None;
+ }
+ }
+
+ if let (None, true) = (iter.next(), sub_slice_end == self.last_slice_end) {
+ // This was the last subslice.
+ sub_slice_end = match first_whitespace {
+ Some(i) => self.last_slice_end + i,
+ None => self.slice.len(),
+ };
+ }
+
+ let kind = match self.last_slice_kind {
+ CodeCharKind::Comment => CodeCharKind::Normal,
+ CodeCharKind::Normal => CodeCharKind::Comment,
+ };
+ let res = (
+ kind,
+ self.last_slice_end,
+ &self.slice[self.last_slice_end..sub_slice_end],
+ );
+ self.last_slice_end = sub_slice_end;
+ self.last_slice_kind = kind;
+
+ Some(res)
+ }
+}
+
+/// Checks is `new` didn't miss any comment from `span`, if it removed any, return previous text
+/// (if it fits in the width/offset, else return `None`), else return `new`
+pub(crate) fn recover_comment_removed(
+ new: String,
+ span: Span,
+ context: &RewriteContext<'_>,
+) -> Option<String> {
+ let snippet = context.snippet(span);
+ if snippet != new && changed_comment_content(snippet, &new) {
+ // We missed some comments. Warn and keep the original text.
+ if context.config.error_on_unformatted() {
+ context.report.append(
+ context.parse_sess.span_to_filename(span),
+ vec![FormattingError::from_span(
+ span,
+ &context.parse_sess,
+ ErrorKind::LostComment,
+ )],
+ );
+ }
+ Some(snippet.to_owned())
+ } else {
+ Some(new)
+ }
+}
+
+pub(crate) fn filter_normal_code(code: &str) -> String {
+ let mut buffer = String::with_capacity(code.len());
+ LineClasses::new(code).for_each(|(kind, line)| match kind {
+ FullCodeCharKind::Normal
+ | FullCodeCharKind::StartString
+ | FullCodeCharKind::InString
+ | FullCodeCharKind::EndString => {
+ buffer.push_str(&line);
+ buffer.push('\n');
+ }
+ _ => (),
+ });
+ if !code.ends_with('\n') && buffer.ends_with('\n') {
+ buffer.pop();
+ }
+ buffer
+}
+
+/// Returns `true` if the two strings of code have the same payload of comments.
+/// The payload of comments is everything in the string except:
+/// - actual code (not comments),
+/// - comment start/end marks,
+/// - whitespace,
+/// - '*' at the beginning of lines in block comments.
+fn changed_comment_content(orig: &str, new: &str) -> bool {
+ // Cannot write this as a fn since we cannot return types containing closures.
+ let code_comment_content = |code| {
+ let slices = UngroupedCommentCodeSlices::new(code);
+ slices
+ .filter(|&(ref kind, _, _)| *kind == CodeCharKind::Comment)
+ .flat_map(|(_, _, s)| CommentReducer::new(s))
+ };
+ let res = code_comment_content(orig).ne(code_comment_content(new));
+ debug!(
+ "comment::changed_comment_content: {}\norig: '{}'\nnew: '{}'\nraw_old: {}\nraw_new: {}",
+ res,
+ orig,
+ new,
+ code_comment_content(orig).collect::<String>(),
+ code_comment_content(new).collect::<String>()
+ );
+ res
+}
+
+/// Iterator over the 'payload' characters of a comment.
+/// It skips whitespace, comment start/end marks, and '*' at the beginning of lines.
+/// The comment must be one comment, ie not more than one start mark (no multiple line comments,
+/// for example).
+struct CommentReducer<'a> {
+ is_block: bool,
+ at_start_line: bool,
+ iter: std::str::Chars<'a>,
+}
+
+impl<'a> CommentReducer<'a> {
+ fn new(comment: &'a str) -> CommentReducer<'a> {
+ let is_block = comment.starts_with("/*");
+ let comment = remove_comment_header(comment);
+ CommentReducer {
+ is_block,
+ // There are no supplementary '*' on the first line.
+ at_start_line: false,
+ iter: comment.chars(),
+ }
+ }
+}
+
+impl<'a> Iterator for CommentReducer<'a> {
+ type Item = char;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ loop {
+ let mut c = self.iter.next()?;
+ if self.is_block && self.at_start_line {
+ while c.is_whitespace() {
+ c = self.iter.next()?;
+ }
+ // Ignore leading '*'.
+ if c == '*' {
+ c = self.iter.next()?;
+ }
+ } else if c == '\n' {
+ self.at_start_line = true;
+ }
+ if !c.is_whitespace() {
+ return Some(c);
+ }
+ }
+ }
+}
+
+fn remove_comment_header(comment: &str) -> &str {
+ if comment.starts_with("///") || comment.starts_with("//!") {
+ &comment[3..]
+ } else if comment.starts_with("//") {
+ &comment[2..]
+ } else if (comment.starts_with("/**") && !comment.starts_with("/**/"))
+ || comment.starts_with("/*!")
+ {
+ &comment[3..comment.len() - 2]
+ } else {
+ assert!(
+ comment.starts_with("/*"),
+ format!("string '{}' is not a comment", comment)
+ );
+ &comment[2..comment.len() - 2]
+ }
+}
+
+#[cfg(test)]
+mod test {
+ use super::*;
+ use crate::shape::{Indent, Shape};
+
+ #[test]
+ fn char_classes() {
+ let mut iter = CharClasses::new("//\n\n".chars());
+
+ assert_eq!((FullCodeCharKind::StartComment, '/'), iter.next().unwrap());
+ assert_eq!((FullCodeCharKind::InComment, '/'), iter.next().unwrap());
+ assert_eq!((FullCodeCharKind::EndComment, '\n'), iter.next().unwrap());
+ assert_eq!((FullCodeCharKind::Normal, '\n'), iter.next().unwrap());
+ assert_eq!(None, iter.next());
+ }
+
+ #[test]
+ fn comment_code_slices() {
+ let input = "code(); /* test */ 1 + 1";
+ let mut iter = CommentCodeSlices::new(input);
+
+ assert_eq!((CodeCharKind::Normal, 0, "code(); "), iter.next().unwrap());
+ assert_eq!(
+ (CodeCharKind::Comment, 8, "/* test */"),
+ iter.next().unwrap()
+ );
+ assert_eq!((CodeCharKind::Normal, 18, " 1 + 1"), iter.next().unwrap());
+ assert_eq!(None, iter.next());
+ }
+
+ #[test]
+ fn comment_code_slices_two() {
+ let input = "// comment\n test();";
+ let mut iter = CommentCodeSlices::new(input);
+
+ assert_eq!((CodeCharKind::Normal, 0, ""), iter.next().unwrap());
+ assert_eq!(
+ (CodeCharKind::Comment, 0, "// comment\n"),
+ iter.next().unwrap()
+ );
+ assert_eq!(
+ (CodeCharKind::Normal, 11, " test();"),
+ iter.next().unwrap()
+ );
+ assert_eq!(None, iter.next());
+ }
+
+ #[test]
+ fn comment_code_slices_three() {
+ let input = "1 // comment\n // comment2\n\n";
+ let mut iter = CommentCodeSlices::new(input);
+
+ assert_eq!((CodeCharKind::Normal, 0, "1 "), iter.next().unwrap());
+ assert_eq!(
+ (CodeCharKind::Comment, 2, "// comment\n // comment2\n"),
+ iter.next().unwrap()
+ );
+ assert_eq!((CodeCharKind::Normal, 29, "\n"), iter.next().unwrap());
+ assert_eq!(None, iter.next());
+ }
+
+ #[test]
+ #[rustfmt::skip]
+ fn format_doc_comments() {
+ let mut wrap_normalize_config: crate::config::Config = Default::default();
+ wrap_normalize_config.set().wrap_comments(true);
+ wrap_normalize_config.set().normalize_comments(true);
+
+ let mut wrap_config: crate::config::Config = Default::default();
+ wrap_config.set().wrap_comments(true);
+
+ let comment = rewrite_comment(" //test",
+ true,
+ Shape::legacy(100, Indent::new(0, 100)),
+ &wrap_normalize_config).unwrap();
+ assert_eq!("/* test */", comment);
+
+ let comment = rewrite_comment("// comment on a",
+ false,
+ Shape::legacy(10, Indent::empty()),
+ &wrap_normalize_config).unwrap();
+ assert_eq!("// comment\n// on a", comment);
+
+ let comment = rewrite_comment("// A multi line comment\n // between args.",
+ false,
+ Shape::legacy(60, Indent::new(0, 12)),
+ &wrap_normalize_config).unwrap();
+ assert_eq!("// A multi line comment\n // between args.", comment);
+
+ let input = "// comment";
+ let expected =
+ "/* comment */";
+ let comment = rewrite_comment(input,
+ true,
+ Shape::legacy(9, Indent::new(0, 69)),
+ &wrap_normalize_config).unwrap();
+ assert_eq!(expected, comment);
+
+ let comment = rewrite_comment("/* trimmed */",
+ true,
+ Shape::legacy(100, Indent::new(0, 100)),
+ &wrap_normalize_config).unwrap();
+ assert_eq!("/* trimmed */", comment);
+
+ // Check that different comment style are properly recognised.
+ let comment = rewrite_comment(r#"/// test1
+ /// test2
+ /*
+ * test3
+ */"#,
+ false,
+ Shape::legacy(100, Indent::new(0, 0)),
+ &wrap_normalize_config).unwrap();
+ assert_eq!("/// test1\n/// test2\n// test3", comment);
+
+ // Check that the blank line marks the end of a commented paragraph.
+ let comment = rewrite_comment(r#"// test1
+
+ // test2"#,
+ false,
+ Shape::legacy(100, Indent::new(0, 0)),
+ &wrap_normalize_config).unwrap();
+ assert_eq!("// test1\n\n// test2", comment);
+
+ // Check that the blank line marks the end of a custom-commented paragraph.
+ let comment = rewrite_comment(r#"//@ test1
+
+ //@ test2"#,
+ false,
+ Shape::legacy(100, Indent::new(0, 0)),
+ &wrap_normalize_config).unwrap();
+ assert_eq!("//@ test1\n\n//@ test2", comment);
+
+ // Check that bare lines are just indented but otherwise left unchanged.
+ let comment = rewrite_comment(r#"// test1
+ /*
+ a bare line!
+
+ another bare line!
+ */"#,
+ false,
+ Shape::legacy(100, Indent::new(0, 0)),
+ &wrap_config).unwrap();
+ assert_eq!("// test1\n/*\n a bare line!\n\n another bare line!\n*/", comment);
+ }
+
+ // This is probably intended to be a non-test fn, but it is not used.
+ // We should keep this around unless it helps us test stuff to remove it.
+ fn uncommented(text: &str) -> String {
+ CharClasses::new(text.chars())
+ .filter_map(|(s, c)| match s {
+ FullCodeCharKind::Normal | FullCodeCharKind::InString => Some(c),
+ _ => None,
+ })
+ .collect()
+ }
+
+ #[test]
+ fn test_uncommented() {
+ assert_eq!(&uncommented("abc/*...*/"), "abc");
+ assert_eq!(
+ &uncommented("// .... /* \n../* /* *** / */ */a/* // */c\n"),
+ "..ac\n"
+ );
+ assert_eq!(&uncommented("abc \" /* */\" qsdf"), "abc \" /* */\" qsdf");
+ }
+
+ #[test]
+ fn test_contains_comment() {
+ assert_eq!(contains_comment("abc"), false);
+ assert_eq!(contains_comment("abc // qsdf"), true);
+ assert_eq!(contains_comment("abc /* kqsdf"), true);
+ assert_eq!(contains_comment("abc \" /* */\" qsdf"), false);
+ }
+
+ #[test]
+ fn test_find_uncommented() {
+ fn check(haystack: &str, needle: &str, expected: Option<usize>) {
+ assert_eq!(expected, haystack.find_uncommented(needle));
+ }
+
+ check("/*/ */test", "test", Some(6));
+ check("//test\ntest", "test", Some(7));
+ check("/* comment only */", "whatever", None);
+ check(
+ "/* comment */ some text /* more commentary */ result",
+ "result",
+ Some(46),
+ );
+ check("sup // sup", "p", Some(2));
+ check("sup", "x", None);
+ check(r#"π? /**/ π is nice!"#, r#"π is nice"#, Some(9));
+ check("/*sup yo? \n sup*/ sup", "p", Some(20));
+ check("hel/*lohello*/lo", "hello", None);
+ check("acb", "ab", None);
+ check(",/*A*/ ", ",", Some(0));
+ check("abc", "abc", Some(0));
+ check("/* abc */", "abc", None);
+ check("/**/abc/* */", "abc", Some(4));
+ check("\"/* abc */\"", "abc", Some(4));
+ check("\"/* abc", "abc", Some(4));
+ }
+
+ #[test]
+ fn test_filter_normal_code() {
+ let s = r#"
+fn main() {
+ println!("hello, world");
+}
+"#;
+ assert_eq!(s, filter_normal_code(s));
+ let s_with_comment = r#"
+fn main() {
+ // hello, world
+ println!("hello, world");
+}
+"#;
+ assert_eq!(s, filter_normal_code(s_with_comment));
+ }
+}
projects / rustc.git / blobdiff