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rust/src/comment.rs
Josh Soref cedb7b5058
Spelling (#5753) 
various spelling fixes
---------

Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>
2024-01-25 18:55:23 -05:00

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// Formatting and tools for comments.
use std::{borrow::Cow, iter};
use itertools::{multipeek, MultiPeek};
use lazy_static::lazy_static;
use regex::Regex;
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,
trimmed_last_line_width, unicode_str_width,
};
use crate::{ErrorKind, FormattingError};
lazy_static! {
/// A regex matching reference doc links.
///
/// ```markdown
/// /// An [example].
/// ///
/// /// [example]: this::is::a::link
/// ```
static ref REFERENCE_LINK_URL: Regex = Regex::new(r"^\[.+\]\s?:").unwrap();
}
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 cannot span multiple lines.
pub(crate) fn is_line_comment(&self) -> bool {
matches!(
self,
CommentStyle::DoubleSlash
| CommentStyle::TripleSlash
| CommentStyle::Doc
| CommentStyle::Custom(_)
)
}
/// Returns `true` if the commenting style can span multiple lines.
pub(crate) fn is_block_comment(&self) -> bool {
matches!(
self,
CommentStyle::SingleBullet | CommentStyle::DoubleBullet | CommentStyle::Exclamation
)
}
/// Returns `true` if the commenting style is for documentation.
pub(crate) fn is_doc_comment(&self) -> bool {
matches!(*self, CommentStyle::TripleSlash | CommentStyle::Doc)
}
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() || trimmed_last_line_width(prev_str) == 0 {
""
} 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 && one_line_width <= 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 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()
&& !(
// `format_code_in_doc_comments` should only take effect on doc comments,
// so we only consider it when this comment block is a doc comment block.
is_doc_comment && 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
)
})
}
}
/// Enum indicating if the code block contains rust based on attributes
enum CodeBlockAttribute {
Rust,
NotRust,
}
impl CodeBlockAttribute {
/// Parse comma separated attributes list. Return rust only if all
/// attributes are valid rust attributes
/// See <https://doc.rust-lang.org/rustdoc/print.html#attributes>
fn new(attributes: &str) -> CodeBlockAttribute {
for attribute in attributes.split(',') {
match attribute.trim() {
"" | "rust" | "should_panic" | "no_run" | "edition2015" | "edition2018"
| "edition2021" => (),
"ignore" | "compile_fail" | "text" => return CodeBlockAttribute::NotRust,
_ => return CodeBlockAttribute::NotRust,
}
}
CodeBlockAttribute::Rust
}
}
/// Block that is formatted as an item.
///
/// An item starts with either a star `*`, a dash `-`, a greater-than `>`, a plus '+', or a number
/// `12.` or `34)` (with at most 2 digits). An item represents CommonMark's ["list
/// items"](https://spec.commonmark.org/0.30/#list-items) and/or ["block
/// quotes"](https://spec.commonmark.org/0.30/#block-quotes), but note that only a subset of
/// CommonMark is recognized - see the doc comment of [`ItemizedBlock::get_marker_length`] for more
/// details.
///
/// 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 characters (typically whitespaces) up to the item marker
indent: usize,
/// the string that marks the start of an item
opener: String,
/// sequence of characters (typically whitespaces) to prefix new lines that are part of the item
line_start: String,
}
impl ItemizedBlock {
/// Checks whether the `trimmed` line includes an item marker. Returns `None` if there is no
/// marker. Returns the length of the marker (in bytes) if one is present. Note that the length
/// includes the whitespace that follows the marker, for example the marker in `"* list item"`
/// has the length of 2.
///
/// This function recognizes item markers that correspond to CommonMark's
/// ["bullet list marker"](https://spec.commonmark.org/0.30/#bullet-list-marker),
/// ["block quote marker"](https://spec.commonmark.org/0.30/#block-quote-marker), and/or
/// ["ordered list marker"](https://spec.commonmark.org/0.30/#ordered-list-marker).
///
/// Compared to CommonMark specification, the number of digits that are allowed in an ["ordered
/// list marker"](https://spec.commonmark.org/0.30/#ordered-list-marker) is more limited (to at
/// most 2 digits). Limiting the length of the marker helps reduce the risk of recognizing
/// arbitrary numbers as markers. See also
/// <https://talk.commonmark.org/t/blank-lines-before-lists-revisited/1990> which gives the
/// following example where a number (i.e. "1868") doesn't signify an ordered list:
/// ```md
/// The Captain died in
/// 1868. He wes buried in...
/// ```
fn get_marker_length(trimmed: &str) -> Option<usize> {
// https://spec.commonmark.org/0.30/#bullet-list-marker or
// https://spec.commonmark.org/0.30/#block-quote-marker
let itemized_start = ["* ", "- ", "> ", "+ "];
if itemized_start.iter().any(|s| trimmed.starts_with(s)) {
return Some(2); // All items in `itemized_start` have length 2.
}
// https://spec.commonmark.org/0.30/#ordered-list-marker, where at most 2 digits are
// allowed.
for suffix in [". ", ") "] {
if let Some((prefix, _)) = trimmed.split_once(suffix) {
let has_leading_digits = (1..=2).contains(&prefix.len())
&& prefix.chars().all(|c| char::is_ascii_digit(&c));
if has_leading_digits {
return Some(prefix.len() + suffix.len());
}
}
}
None // No markers found.
}
/// Creates a new `ItemizedBlock` described with the given `line`.
/// Returns `None` if `line` doesn't start an item.
fn new(line: &str) -> Option<ItemizedBlock> {
let marker_length = ItemizedBlock::get_marker_length(line.trim_start())?;
let space_to_marker = line.chars().take_while(|c| c.is_whitespace()).count();
let mut indent = space_to_marker + marker_length;
let mut line_start = " ".repeat(indent);
// Markdown blockquote start with a "> "
if line.trim_start().starts_with('>') {
// remove the original +2 indent because there might be multiple nested block quotes
// and it's easier to reason about the final indent by just taking the length
// of the new line_start. We update the indent because it effects the max width
// of each formatted line.
line_start = itemized_block_quote_start(line, line_start, 2);
indent = line_start.len();
}
Some(ItemizedBlock {
lines: vec![line[indent..].to_string()],
indent,
opener: line[..indent].to_string(),
line_start,
})
}
/// 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::get_marker_length(line.trim_start()).is_none()
&& 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")
}
}
/// Determine the line_start when formatting markdown block quotes.
/// The original line_start likely contains indentation (whitespaces), which we'd like to
/// replace with '> ' characters.
fn itemized_block_quote_start(line: &str, mut line_start: String, remove_indent: usize) -> String {
let quote_level = line
.chars()
.take_while(|c| !c.is_alphanumeric())
.fold(0, |acc, c| if c == '>' { acc + 1 } else { acc });
for _ in 0..remove_indent {
line_start.pop();
}
for _ in 0..quote_level {
line_start.push_str("> ")
}
line_start
}
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,
style: CommentStyle<'a>,
}
impl<'a> CommentRewrite<'a> {
fn new(
orig: &'a str,
block_style: bool,
shape: Shape,
config: &'a Config,
) -> CommentRewrite<'a> {
let ((opener, closer, line_start), style) = if block_style {
(
CommentStyle::SingleBullet.to_str_tuplet(),
CommentStyle::SingleBullet,
)
} else {
let style = comment_style(orig, config.normalize_comments());
(style.to_str_tuplet(), style)
};
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(),
style,
};
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(&"") => sep.trim_end(),
Some(..) => sep,
None => "",
});
}
result
}
/// Check if any characters were written to the result buffer after the start of the comment.
/// when calling [`CommentRewrite::new()`] the result buffer is initialized with the opening
/// characters for the comment.
fn buffer_contains_comment(&self) -> bool {
// if self.result.len() < self.opener.len() then an empty comment is in the buffer
// if self.result.len() > self.opener.len() then a non empty comment is in the buffer
self.result.len() != self.opener.len()
}
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);
// only push a comment_line_separator for ItemizedBlocks if the comment is not empty
if self.buffer_contains_comment() {
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,
is_doc_comment: bool,
) -> bool {
let num_newlines = count_newlines(orig);
let is_last = i == num_newlines;
let needs_new_comment_line = if self.style.is_block_comment() {
num_newlines > 0 || self.buffer_contains_comment()
} else {
self.buffer_contains_comment()
};
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);
// only push a comment_line_separator if we need to start a new comment line
if needs_new_comment_line {
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::Rust
if self.fmt.config.format_code_in_doc_comments()
&& !self.code_block_buffer.trim().is_empty() =>
{
let mut config = self.fmt.config.clone();
config.set().wrap_comments(false);
let comment_max_width = config
.doc_comment_code_block_width()
.min(config.max_width());
config.set().max_width(comment_max_width);
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)
}
}
_ => 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 let Some(stripped) = line.strip_prefix("```") {
self.code_block_attr = Some(CodeBlockAttribute::new(stripped))
} else if self.fmt.config.wrap_comments() {
if let Some(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();
}
}
let is_markdown_header_doc_comment = is_doc_comment && line.starts_with('#');
// We only want to wrap the comment if:
// 1) wrap_comments = true is configured
// 2) The comment is not the start of a markdown header doc comment
// 3) The comment width exceeds the shape's width
// 4) No URLS were found in the comment
// If this changes, the documentation in ../Configurations.md#wrap_comments
// should be changed accordingly.
let should_wrap_comment = self.fmt.config.wrap_comments()
&& !is_markdown_header_doc_comment
&& unicode_str_width(line) > self.fmt.shape.width
&& !has_url(line)
&& !is_table_item(line);
if should_wrap_comment {
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, is_doc_comment) {
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://")
|| REFERENCE_LINK_URL.is_match(s)
}
/// Returns true if the given string may be part of a Markdown table.
fn is_table_item(mut s: &str) -> bool {
// This function may return false positive, but should get its job done in most cases (i.e.
// markdown tables with two column delimiters).
s = s.trim_start();
return s.starts_with('|')
&& match s.rfind('|') {
Some(0) | None => false,
_ => true,
};
}
/// 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 let Some(stripped) = line.strip_prefix(opener) {
(stripped, 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 let Some(stripped) = line.strip_prefix('*') {
(stripped, false)
} else {
(line, line.starts_with(' '))
}
}
pub(crate) trait FindUncommented {
fn find_uncommented(&self, pat: &str) -> Option<usize>;
fn find_last_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()),
}
}
fn find_last_uncommented(&self, pat: &str) -> Option<usize> {
if let Some(left) = self.find_uncommented(pat) {
let mut result = left;
// add 1 to use find_last_uncommented for &str after pat
while let Some(next) = self[(result + 1)..].find_last_uncommented(pat) {
result += next + 1;
}
Some(result)
} else {
None
}
}
}
// 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 multiline string inside a comment
StartStringCommented,
/// End of a multiline string inside a comment
EndStringCommented,
/// Inside a commented string
InStringCommented,
/// Start of a multiline string
StartString,
/// End of a multiline 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 if chr == '*' && self.base.peek().map(RichChar::get_char) == Some('/') {
char_kind = FullCodeCharKind::InComment;
CharClassesStatus::BlockCommentClosing(deepness - 1)
} 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!(),
};
for (kind, c) in self.base.by_ref() {
// 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(|(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 let Some(stripped) = comment.strip_prefix("//") {
stripped
} else if (comment.starts_with("/**") && !comment.starts_with("/**/"))
|| comment.starts_with("/*!")
{
&comment[3..comment.len() - 2]
} else {
assert!(
comment.starts_with("/*"),
"string '{comment}' is not a comment"
);
&comment[2..comment.len() - 2]
}
}
#[cfg(test)]
mod test {
use super::*;
#[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));
}
#[test]
fn test_itemized_block_first_line_handling() {
fn run_test(
test_input: &str,
expected_line: &str,
expected_indent: usize,
expected_opener: &str,
expected_line_start: &str,
) {
let block = ItemizedBlock::new(test_input).unwrap();
assert_eq!(1, block.lines.len(), "test_input: {test_input:?}");
assert_eq!(expected_line, &block.lines[0], "test_input: {test_input:?}");
assert_eq!(expected_indent, block.indent, "test_input: {test_input:?}");
assert_eq!(expected_opener, &block.opener, "test_input: {test_input:?}");
assert_eq!(
expected_line_start, &block.line_start,
"test_input: {test_input:?}"
);
}
run_test("- foo", "foo", 2, "- ", " ");
run_test("* foo", "foo", 2, "* ", " ");
run_test("> foo", "foo", 2, "> ", "> ");
run_test("1. foo", "foo", 3, "1. ", " ");
run_test("12. foo", "foo", 4, "12. ", " ");
run_test("1) foo", "foo", 3, "1) ", " ");
run_test("12) foo", "foo", 4, "12) ", " ");
run_test(" - foo", "foo", 6, " - ", " ");
// https://spec.commonmark.org/0.30 says: "A start number may begin with 0s":
run_test("0. foo", "foo", 3, "0. ", " ");
run_test("01. foo", "foo", 4, "01. ", " ");
}
#[test]
fn test_itemized_block_nonobvious_markers_are_rejected() {
let test_inputs = vec![
// Non-numeric item markers (e.g. `a.` or `iv.`) are not allowed by
// https://spec.commonmark.org/0.30/#ordered-list-marker. We also note that allowing
// them would risk misidentifying regular words as item markers. See also the
// discussion in https://talk.commonmark.org/t/blank-lines-before-lists-revisited/1990
"word. rest of the paragraph.",
"a. maybe this is a list item? maybe not?",
"iv. maybe this is a list item? maybe not?",
// Numbers with 3 or more digits are not recognized as item markers, to avoid
// formatting the following example as a list:
//
// ```
// The Captain died in
// 1868. He was buried in...
// ```
"123. only 2-digit numbers are recognized as item markers.",
// Parens:
"123) giving some coverage to parens as well.",
"a) giving some coverage to parens as well.",
// https://spec.commonmark.org/0.30 says that "at least one space or tab is needed
// between the list marker and any following content":
"1.Not a list item.",
"1.2.3. Not a list item.",
"1)Not a list item.",
"-Not a list item.",
"+Not a list item.",
"+1 not a list item.",
// https://spec.commonmark.org/0.30 says: "A start number may not be negative":
"-1. Not a list item.",
"-1 Not a list item.",
// Marker without prefix are not recognized as item markers:
". Not a list item.",
") Not a list item.",
];
for line in test_inputs.iter() {
let maybe_block = ItemizedBlock::new(line);
assert!(
maybe_block.is_none(),
"The following line shouldn't be classified as a list item: {line}"
);
}
}
}
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