rust/src/comment.rs
Seiichi Uchida dfc67a5df7 Cargo clippy
2018-01-26 14:53:28 +09:00

1230 lines
42 KiB
Rust

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Formatting and tools for comments.
use std::{self, iter};
use syntax::codemap::Span;
use config::Config;
use rewrite::RewriteContext;
use shape::{Indent, Shape};
use string::{rewrite_string, StringFormat};
use utils::{count_newlines, first_line_width, last_line_width};
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 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 + 1])
})
}
impl<'a> CommentStyle<'a> {
pub fn opener(&self) -> &'a str {
match *self {
CommentStyle::DoubleSlash => "// ",
CommentStyle::TripleSlash => "/// ",
CommentStyle::Doc => "//! ",
CommentStyle::SingleBullet => "/* ",
CommentStyle::DoubleBullet => "/** ",
CommentStyle::Exclamation => "/*! ",
CommentStyle::Custom(opener) => opener,
}
}
pub fn closer(&self) -> &'a str {
match *self {
CommentStyle::DoubleSlash
| CommentStyle::TripleSlash
| CommentStyle::Custom(..)
| CommentStyle::Doc => "",
CommentStyle::DoubleBullet => " **/",
CommentStyle::SingleBullet | CommentStyle::Exclamation => " */",
}
}
pub fn line_start(&self) -> &'a str {
match *self {
CommentStyle::DoubleSlash => "// ",
CommentStyle::TripleSlash => "/// ",
CommentStyle::Doc => "//! ",
CommentStyle::SingleBullet | CommentStyle::Exclamation => " * ",
CommentStyle::DoubleBullet => " ** ",
CommentStyle::Custom(opener) => opener,
}
}
pub fn to_str_tuplet(&self) -> (&'a str, &'a str, &'a str) {
(self.opener(), self.closer(), self.line_start())
}
pub fn line_with_same_comment_style(&self, line: &str, normalize_comments: bool) -> bool {
match *self {
CommentStyle::DoubleSlash | CommentStyle::TripleSlash | CommentStyle::Doc => {
line.trim_left().starts_with(self.line_start().trim_left())
|| comment_style(line, normalize_comments) == *self
}
CommentStyle::DoubleBullet | CommentStyle::SingleBullet | CommentStyle::Exclamation => {
line.trim_left().starts_with(self.closer().trim_left())
|| line.trim_left().starts_with(self.line_start().trim_left())
|| comment_style(line, normalize_comments) == *self
}
CommentStyle::Custom(opener) => line.trim_left().starts_with(opener.trim_right()),
}
}
}
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
}
}
pub fn combine_strs_with_missing_comments(
context: &RewriteContext,
prev_str: &str,
next_str: &str,
span: Span,
shape: Shape,
allow_extend: bool,
) -> Option<String> {
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 indent_str = shape.indent.to_string(context.config);
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 {
return Some(format!("{}{}{}", prev_str, first_sep, next_str));
} else {
let sep = if prev_str.is_empty() {
String::new()
} else {
String::from("\n") + &indent_str
};
return Some(format!("{}{}{}", prev_str, sep, next_str));
}
}
// 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.chars().position(|c| c == '/') {
!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() {
String::new()
} 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 {
String::from(" ")
} else {
format!("\n{}", indent_str)
}
};
let second_sep = if missing_comment.is_empty() || next_str.is_empty() {
String::new()
} else if missing_comment.starts_with("//") {
format!("\n{}", indent_str)
} 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 {
String::from(" ")
} else {
format!("\n{}", indent_str)
}
};
Some(format!(
"{}{}{}{}{}",
prev_str, first_sep, missing_comment, second_sep, next_str,
))
}
pub fn rewrite_comment(
orig: &str,
block_style: bool,
shape: Shape,
config: &Config,
) -> Option<String> {
// If there are lines without a starting sigil, we won't format them correctly
// so in that case we won't even re-align (if !config.normalize_comments()) and
// we should stop now.
let num_bare_lines = orig.lines()
.map(|line| line.trim())
.filter(|l| !(l.starts_with('*') || l.starts_with("//") || l.starts_with("/*")))
.count();
if num_bare_lines > 0 && !config.normalize_comments() {
return Some(orig.to_owned());
}
if !config.normalize_comments() && !config.wrap_comments() {
return light_rewrite_comment(orig, shape.indent, config);
}
identify_comment(orig, block_style, shape, config)
}
fn identify_comment(
orig: &str,
block_style: bool,
shape: Shape,
config: &Config,
) -> Option<String> {
let style = comment_style(orig, false);
let first_group = orig.lines()
.take_while(|l| style.line_with_same_comment_style(l, false))
.collect::<Vec<_>>()
.join("\n");
let rest = orig.lines()
.skip(first_group.lines().count())
.collect::<Vec<_>>()
.join("\n");
let first_group_str = rewrite_comment_inner(&first_group, block_style, style, shape, config)?;
if rest.is_empty() {
Some(first_group_str)
} else {
identify_comment(&rest, block_style, shape, config).map(|rest_str| {
format!(
"{}\n{}{}",
first_group_str,
shape.indent.to_string(config),
rest_str
)
})
}
}
fn rewrite_comment_inner(
orig: &str,
block_style: bool,
style: CommentStyle,
shape: Shape,
config: &Config,
) -> Option<String> {
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_chars = shape
.width
.checked_sub(closer.len() + opener.len())
.unwrap_or(1);
let indent_str = shape.indent.to_string(config);
let fmt_indent = shape.indent + (opener.len() - line_start.len());
let mut fmt = StringFormat {
opener: "",
closer: "",
line_start: line_start,
line_end: "",
shape: Shape::legacy(max_chars, fmt_indent),
trim_end: true,
config: config,
};
let line_breaks = count_newlines(orig.trim_right());
let lines = orig.lines()
.enumerate()
.map(|(i, mut line)| {
line = line.trim();
// Drop old closer.
if i == line_breaks && line.ends_with("*/") && !line.starts_with("//") {
line = line[..(line.len() - 2)].trim_right();
}
line
})
.map(|s| left_trim_comment_line(s, &style))
.map(|(line, has_leading_whitespace)| {
if orig.starts_with("/*") && line_breaks == 0 {
(
line.trim_left(),
has_leading_whitespace || config.normalize_comments(),
)
} else {
(line, has_leading_whitespace || config.normalize_comments())
}
});
let mut result = String::with_capacity(orig.len() * 2);
result.push_str(opener);
let mut code_block_buffer = String::with_capacity(128);
let mut is_prev_line_multi_line = false;
let mut inside_code_block = false;
let comment_line_separator = format!("\n{}{}", indent_str, line_start);
let join_code_block_with_comment_line_separator = |s: &str| {
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() => comment_line_separator.trim_right(),
Some(..) => &comment_line_separator,
None => "",
});
}
result
};
for (i, (line, has_leading_whitespace)) in lines.enumerate() {
let is_last = i == count_newlines(orig);
if inside_code_block {
if line.starts_with("```") {
inside_code_block = false;
result.push_str(&comment_line_separator);
let code_block = ::format_code_block(&code_block_buffer, config)
.unwrap_or_else(|| code_block_buffer.to_owned());
result.push_str(&join_code_block_with_comment_line_separator(&code_block));
code_block_buffer.clear();
result.push_str(&comment_line_separator);
result.push_str(line);
} else {
code_block_buffer.push_str(line);
code_block_buffer.push('\n');
}
continue;
} else {
inside_code_block = line.starts_with("```");
if result == opener {
let force_leading_whitespace = opener == "/* " && count_newlines(orig) == 0;
if !has_leading_whitespace && !force_leading_whitespace && result.ends_with(' ') {
result.pop();
}
if line.is_empty() {
continue;
}
} else if is_prev_line_multi_line && !line.is_empty() {
result.push(' ')
} else if is_last && !closer.is_empty() && line.is_empty() {
result.push('\n');
result.push_str(&indent_str);
} else {
result.push_str(&comment_line_separator);
if !has_leading_whitespace && result.ends_with(' ') {
result.pop();
}
}
}
if config.wrap_comments() && line.len() > fmt.shape.width && !has_url(line) {
match rewrite_string(line, &fmt, Some(max_chars)) {
Some(ref s) => {
is_prev_line_multi_line = s.contains('\n');
result.push_str(s);
}
None if 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.
result.pop();
result.push_str(&comment_line_separator);
fmt.shape = Shape::legacy(max_chars, fmt_indent);
match rewrite_string(line, &fmt, Some(max_chars)) {
Some(ref s) => {
is_prev_line_multi_line = s.contains('\n');
result.push_str(s);
}
None => {
is_prev_line_multi_line = false;
result.push_str(line);
}
}
}
None => {
is_prev_line_multi_line = false;
result.push_str(line);
}
}
fmt.shape = if is_prev_line_multi_line {
// 1 = " "
let offset = 1 + last_line_width(&result) - line_start.len();
Shape {
width: max_chars.checked_sub(offset).unwrap_or(0),
indent: fmt_indent,
offset: fmt.shape.offset + offset,
}
} else {
Shape::legacy(max_chars, fmt_indent)
};
} else {
if line.is_empty() && result.ends_with(' ') && !is_last {
// Remove space if this is an empty comment or a doc comment.
result.pop();
}
result.push_str(line);
fmt.shape = Shape::legacy(max_chars, fmt_indent);
is_prev_line_multi_line = false;
}
}
result.push_str(closer);
if result == opener && result.ends_with(' ') {
// Trailing space.
result.pop();
}
Some(result)
}
/// 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 fn rewrite_missing_comment(
span: Span,
shape: Shape,
context: &RewriteContext,
) -> Option<String> {
let missing_snippet = context.snippet(span);
let trimmed_snippet = missing_snippet.trim();
if !trimmed_snippet.is_empty() {
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 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.chars().position(|c| c == '/').unwrap_or(0);
// 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 {
format!("\n{}", shape.indent.to_string(context.config))
} else {
String::from(" ")
};
Some(format!("{}{}", sep, missing_comment))
}
}
/// Trims whitespace and aligns to indent, but otherwise does not change comments.
fn light_rewrite_comment(orig: &str, offset: Indent, config: &Config) -> Option<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));
if let Some(fnw) = first_non_whitespace {
if l.as_bytes()[fnw] == b'*' && fnw > 0 {
&l[fnw - 1..]
} else {
&l[fnw..]
}
} else {
""
}.trim_right()
})
.collect();
Some(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_right().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 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 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 fn contains_comment(text: &str) -> bool {
CharClasses::new(text.chars()).any(|(kind, _)| kind.is_comment())
}
/// Remove trailing spaces from the specified snippet. We do not remove spaces
/// inside strings or comments.
pub fn remove_trailing_white_spaces(text: &str) -> String {
let mut buffer = String::with_capacity(text.len());
let mut space_buffer = String::with_capacity(128);
for (char_kind, c) in CharClasses::new(text.chars()) {
match c {
'\n' => {
if char_kind == FullCodeCharKind::InString {
buffer.push_str(&space_buffer);
}
space_buffer.clear();
buffer.push('\n');
}
_ if c.is_whitespace() => {
space_buffer.push(c);
}
_ => {
if !space_buffer.is_empty() {
buffer.push_str(&space_buffer);
space_buffer.clear();
}
buffer.push(c);
}
}
}
buffer
}
pub struct CharClasses<T>
where
T: Iterator,
T::Item: RichChar,
{
base: iter::Peekable<T>,
status: CharClassesStatus,
}
pub 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
}
}
impl RichChar for (char, usize) {
fn get_char(&self) -> char {
self.0
}
}
#[derive(PartialEq, Eq, Debug, Clone, Copy)]
enum CharClassesStatus {
Normal,
LitString,
LitStringEscape,
LitChar,
LitCharEscape,
// The u32 is the nesting deepness of the comment
BlockComment(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),
LineComment,
}
/// Distinguish between functional part of code and comments
#[derive(PartialEq, Eq, Debug, Clone, Copy)]
pub 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 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,
/// Inside a string.
InString,
}
impl FullCodeCharKind {
pub fn is_comment(&self) -> bool {
match *self {
FullCodeCharKind::StartComment
| FullCodeCharKind::InComment
| FullCodeCharKind::EndComment => true,
_ => false,
}
}
pub fn is_string(&self) -> bool {
*self == FullCodeCharKind::InString
}
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 fn new(base: T) -> CharClasses<T> {
CharClasses {
base: base.peekable(),
status: CharClassesStatus::Normal,
}
}
}
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::LitString => match chr {
'"' => CharClassesStatus::Normal,
'\\' => {
char_kind = FullCodeCharKind::InString;
CharClassesStatus::LitStringEscape
}
_ => {
char_kind = FullCodeCharKind::InString;
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 {
'"' => {
char_kind = FullCodeCharKind::InString;
CharClassesStatus::LitString
}
'\'' => CharClassesStatus::LitChar,
'/' => 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::BlockComment(deepness) => {
assert_ne!(deepness, 0);
self.status = 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)
}
_ => CharClassesStatus::BlockComment(deepness),
};
return Some((FullCodeCharKind::InComment, item));
}
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))
}
}
/// 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
while let Some((FullCodeCharKind::InComment, (_, _))) = self.iter.next() {}
}
_ => 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 struct CommentCodeSlices<'a> {
slice: &'a str,
last_slice_kind: CodeCharKind,
last_slice_end: usize,
}
impl<'a> CommentCodeSlices<'a> {
pub fn new(slice: &'a str) -> CommentCodeSlices<'a> {
CommentCodeSlices {
slice: 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 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. Keep the original text.
Some(snippet.to_owned())
} else {
Some(new)
}
}
/// Return 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: is_block,
at_start_line: false, // There are no supplementary '*' on the first line
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::{contains_comment, rewrite_comment, CharClasses, CodeCharKind, CommentCodeSlices,
FindUncommented, FullCodeCharKind};
use 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]
#[cfg_attr(rustfmt, rustfmt_skip)]
fn format_comments() {
let mut config: ::config::Config = Default::default();
config.set().wrap_comments(true);
config.set().normalize_comments(true);
let comment = rewrite_comment(" //test",
true,
Shape::legacy(100, Indent::new(0, 100)),
&config).unwrap();
assert_eq!("/* test */", comment);
let comment = rewrite_comment("// comment on a",
false,
Shape::legacy(10, Indent::empty()),
&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)),
&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)),
&config).unwrap();
assert_eq!(expected, comment);
let comment = rewrite_comment("/* trimmed */",
true,
Shape::legacy(100, Indent::new(0, 100)),
&config).unwrap();
assert_eq!("/* trimmed */", comment);
}
// This is probably intended to be a non-test fn, but it is not used. I'm
// keeping it around unless it helps us test stuff.
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));
}
}