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lib.rs
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#![deny(rust_2018_idioms)]
#[macro_use]
extern crate derive_new;
#[cfg(test)]
#[macro_use]
extern crate lazy_static;
#[macro_use]
extern crate log;
#[macro_use]
extern crate serde_derive;
use std::cell::RefCell;
use std::collections::HashMap;
use std::fmt;
use std::io::{self, Write};
use std::mem;
use std::panic;
use std::path::PathBuf;
use std::rc::Rc;
use failure::Fail;
use syntax::ast;
use crate::comment::LineClasses;
use crate::formatting::{FormatErrorMap, FormattingError, ReportedErrors, SourceFile};
use crate::issues::Issue;
use crate::shape::Indent;
use crate::utils::indent_next_line;
pub use crate::config::{
load_config, CliOptions, Color, Config, Edition, EmitMode, FileLines, FileName, NewlineStyle,
Range, Verbosity,
};
#[macro_use]
mod utils;
mod attr;
mod chains;
pub(crate) mod checkstyle;
mod closures;
mod comment;
pub(crate) mod config;
mod expr;
pub(crate) mod formatting;
mod imports;
mod issues;
mod items;
mod lists;
mod macros;
mod matches;
mod missed_spans;
pub(crate) mod modules;
mod overflow;
mod pairs;
mod patterns;
mod reorder;
mod rewrite;
pub(crate) mod rustfmt_diff;
mod shape;
pub(crate) mod source_file;
pub(crate) mod source_map;
mod spanned;
mod string;
#[cfg(test)]
mod test;
mod types;
mod vertical;
pub(crate) mod visitor;
/// The various errors that can occur during formatting. Note that not all of
/// these can currently be propagated to clients.
#[derive(Fail, Debug)]
pub enum ErrorKind {
/// Line has exceeded character limit (found, maximum).
#[fail(
display = "line formatted, but exceeded maximum width \
(maximum: {} (see `max_width` option), found: {})",
_1, _0
)]
LineOverflow(usize, usize),
/// Line ends in whitespace.
#[fail(display = "left behind trailing whitespace")]
TrailingWhitespace,
/// TODO or FIXME item without an issue number.
#[fail(display = "found {}", _0)]
BadIssue(Issue),
/// License check has failed.
#[fail(display = "license check failed")]
LicenseCheck,
/// Used deprecated skip attribute.
#[fail(display = "`rustfmt_skip` is deprecated; use `rustfmt::skip`")]
DeprecatedAttr,
/// Used a rustfmt:: attribute other than skip.
#[fail(display = "invalid attribute")]
BadAttr,
/// An io error during reading or writing.
#[fail(display = "io error: {}", _0)]
IoError(io::Error),
/// Parse error occurred when parsing the input.
#[fail(display = "parse error")]
ParseError,
/// The user mandated a version and the current version of Rustfmt does not
/// satisfy that requirement.
#[fail(display = "version mismatch")]
VersionMismatch,
/// If we had formatted the given node, then we would have lost a comment.
#[fail(display = "not formatted because a comment would be lost")]
LostComment,
}
impl ErrorKind {
fn is_comment(&self) -> bool {
match self {
ErrorKind::LostComment => true,
_ => false,
}
}
}
impl From<io::Error> for ErrorKind {
fn from(e: io::Error) -> ErrorKind {
ErrorKind::IoError(e)
}
}
/// Result of formatting a snippet of code along with ranges of lines that didn't get formatted,
/// i.e., that got returned as they were originally.
#[derive(Debug)]
struct FormattedSnippet {
snippet: String,
non_formatted_ranges: Vec<(usize, usize)>,
}
impl FormattedSnippet {
/// In case the snippet needed to be wrapped in a function, this shifts down the ranges of
/// non-formatted code.
fn unwrap_code_block(&mut self) {
self.non_formatted_ranges
.iter_mut()
.for_each(|(low, high)| {
*low -= 1;
*high -= 1;
});
}
/// Returns `true` if the line n did not get formatted.
fn is_line_non_formatted(&self, n: usize) -> bool {
self.non_formatted_ranges
.iter()
.any(|(low, high)| *low <= n && n <= *high)
}
}
/// Reports on any issues that occurred during a run of Rustfmt.
///
/// Can be reported to the user via its `Display` implementation of `print_fancy`.
#[derive(Clone)]
pub struct FormatReport {
// Maps stringified file paths to their associated formatting errors.
internal: Rc<RefCell<(FormatErrorMap, ReportedErrors)>>,
non_formatted_ranges: Vec<(usize, usize)>,
}
impl FormatReport {
fn new() -> FormatReport {
FormatReport {
internal: Rc::new(RefCell::new((HashMap::new(), ReportedErrors::default()))),
non_formatted_ranges: Vec::new(),
}
}
fn add_non_formatted_ranges(&mut self, mut ranges: Vec<(usize, usize)>) {
self.non_formatted_ranges.append(&mut ranges);
}
fn append(&self, f: FileName, mut v: Vec<FormattingError>) {
self.track_errors(&v);
self.internal
.borrow_mut()
.0
.entry(f)
.and_modify(|fe| fe.append(&mut v))
.or_insert(v);
}
fn track_errors(&self, new_errors: &[FormattingError]) {
let errs = &mut self.internal.borrow_mut().1;
if !new_errors.is_empty() {
errs.has_formatting_errors = true;
}
if errs.has_operational_errors && errs.has_check_errors {
return;
}
for err in new_errors {
match err.kind {
ErrorKind::LineOverflow(..) | ErrorKind::TrailingWhitespace => {
errs.has_operational_errors = true;
}
ErrorKind::BadIssue(_)
| ErrorKind::LicenseCheck
| ErrorKind::DeprecatedAttr
| ErrorKind::BadAttr
| ErrorKind::VersionMismatch => {
errs.has_check_errors = true;
}
_ => {}
}
}
}
fn add_diff(&mut self) {
self.internal.borrow_mut().1.has_diff = true;
}
fn add_macro_format_failure(&mut self) {
self.internal.borrow_mut().1.has_macro_format_failure = true;
}
fn add_parsing_error(&mut self) {
self.internal.borrow_mut().1.has_parsing_errors = true;
}
fn warning_count(&self) -> usize {
self.internal
.borrow()
.0
.iter()
.map(|(_, errors)| errors.len())
.sum()
}
/// Whether any warnings or errors are present in the report.
pub fn has_warnings(&self) -> bool {
self.internal.borrow().1.has_formatting_errors
}
/// Print the report to a terminal using colours and potentially other
/// fancy output.
pub fn fancy_print(
&self,
mut t: Box<dyn term::Terminal<Output = io::Stderr>>,
) -> Result<(), term::Error> {
for (file, errors) in &self.internal.borrow().0 {
for error in errors {
let prefix_space_len = error.line.to_string().len();
let prefix_spaces = " ".repeat(1 + prefix_space_len);
// First line: the overview of error
t.fg(term::color::RED)?;
t.attr(term::Attr::Bold)?;
write!(t, "{} ", error.msg_prefix())?;
t.reset()?;
t.attr(term::Attr::Bold)?;
writeln!(t, "{}", error.kind)?;
// Second line: file info
write!(t, "{}--> ", &prefix_spaces[1..])?;
t.reset()?;
writeln!(t, "{}:{}", file, error.line)?;
// Third to fifth lines: show the line which triggered error, if available.
if !error.line_buffer.is_empty() {
let (space_len, target_len) = error.format_len();
t.attr(term::Attr::Bold)?;
write!(t, "{}|\n{} | ", prefix_spaces, error.line)?;
t.reset()?;
writeln!(t, "{}", error.line_buffer)?;
t.attr(term::Attr::Bold)?;
write!(t, "{}| ", prefix_spaces)?;
t.fg(term::color::RED)?;
writeln!(t, "{}", FormatReport::target_str(space_len, target_len))?;
t.reset()?;
}
// The last line: show note if available.
let msg_suffix = error.msg_suffix();
if !msg_suffix.is_empty() {
t.attr(term::Attr::Bold)?;
write!(t, "{}= note: ", prefix_spaces)?;
t.reset()?;
writeln!(t, "{}", error.msg_suffix())?;
} else {
writeln!(t)?;
}
t.reset()?;
}
}
if !self.internal.borrow().0.is_empty() {
t.attr(term::Attr::Bold)?;
write!(t, "warning: ")?;
t.reset()?;
write!(
t,
"rustfmt may have failed to format. See previous {} errors.\n\n",
self.warning_count(),
)?;
}
Ok(())
}
fn target_str(space_len: usize, target_len: usize) -> String {
let empty_line = " ".repeat(space_len);
let overflowed = "^".repeat(target_len);
empty_line + &overflowed
}
}
impl fmt::Display for FormatReport {
// Prints all the formatting errors.
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
for (file, errors) in &self.internal.borrow().0 {
for error in errors {
let prefix_space_len = error.line.to_string().len();
let prefix_spaces = " ".repeat(1 + prefix_space_len);
let error_line_buffer = if error.line_buffer.is_empty() {
String::from(" ")
} else {
let (space_len, target_len) = error.format_len();
format!(
"{}|\n{} | {}\n{}| {}",
prefix_spaces,
error.line,
error.line_buffer,
prefix_spaces,
FormatReport::target_str(space_len, target_len)
)
};
let error_info = format!("{} {}", error.msg_prefix(), error.kind);
let file_info = format!("{}--> {}:{}", &prefix_spaces[1..], file, error.line);
let msg_suffix = error.msg_suffix();
let note = if msg_suffix.is_empty() {
String::new()
} else {
format!("{}note= ", prefix_spaces)
};
writeln!(
fmt,
"{}\n{}\n{}\n{}{}",
error_info,
file_info,
error_line_buffer,
note,
error.msg_suffix()
)?;
}
}
if !self.internal.borrow().0.is_empty() {
writeln!(
fmt,
"warning: rustfmt may have failed to format. See previous {} errors.",
self.warning_count(),
)?;
}
Ok(())
}
}
/// Format the given snippet. The snippet is expected to be *complete* code.
/// When we cannot parse the given snippet, this function returns `None`.
fn format_snippet(snippet: &str, config: &Config) -> Option<FormattedSnippet> {
let mut config = config.clone();
panic::catch_unwind(|| {
let mut out: Vec<u8> = Vec::with_capacity(snippet.len() * 2);
config.set().emit_mode(config::EmitMode::Stdout);
config.set().verbose(Verbosity::Quiet);
config.set().hide_parse_errors(true);
let (formatting_error, result) = {
let input = Input::Text(snippet.into());
let mut session = Session::new(config, Some(&mut out));
let result = session.format(input);
(
session.errors.has_macro_format_failure
|| session.out.as_ref().unwrap().is_empty() && !snippet.is_empty()
|| result.is_err(),
result,
)
};
if formatting_error {
None
} else {
String::from_utf8(out).ok().map(|snippet| FormattedSnippet {
snippet,
non_formatted_ranges: result.unwrap().non_formatted_ranges,
})
}
})
// Discard panics encountered while formatting the snippet
// The ? operator is needed to remove the extra Option
.ok()?
}
/// Format the given code block. Mainly targeted for code block in comment.
/// The code block may be incomplete (i.e., parser may be unable to parse it).
/// To avoid panic in parser, we wrap the code block with a dummy function.
/// The returned code block does **not** end with newline.
fn format_code_block(code_snippet: &str, config: &Config) -> Option<FormattedSnippet> {
const FN_MAIN_PREFIX: &str = "fn main() {\n";
fn enclose_in_main_block(s: &str, config: &Config) -> String {
let indent = Indent::from_width(config, config.tab_spaces());
let mut result = String::with_capacity(s.len() * 2);
result.push_str(FN_MAIN_PREFIX);
let mut need_indent = true;
for (kind, line) in LineClasses::new(s) {
if need_indent {
result.push_str(&indent.to_string(config));
}
result.push_str(&line);
result.push('\n');
need_indent = indent_next_line(kind, &line, config);
}
result.push('}');
result
}
// Wrap the given code block with `fn main()` if it does not have one.
let snippet = enclose_in_main_block(code_snippet, config);
let mut result = String::with_capacity(snippet.len());
let mut is_first = true;
// While formatting the code, ignore the config's newline style setting and always use "\n"
// instead of "\r\n" for the newline characters. This is ok because the output here is
// not directly outputted by rustfmt command, but used by the comment formatter's input.
// We have output-file-wide "\n" ==> "\r\n" conversion process after here if it's necessary.
let mut config_with_unix_newline = config.clone();
config_with_unix_newline
.set()
.newline_style(NewlineStyle::Unix);
let mut formatted = format_snippet(&snippet, &config_with_unix_newline)?;
// Remove wrapping main block
formatted.unwrap_code_block();
// Trim "fn main() {" on the first line and "}" on the last line,
// then unindent the whole code block.
let block_len = formatted
.snippet
.rfind('}')
.unwrap_or(formatted.snippet.len());
let mut is_indented = true;
for (kind, ref line) in LineClasses::new(&formatted.snippet[FN_MAIN_PREFIX.len()..block_len]) {
if !is_first {
result.push('\n');
} else {
is_first = false;
}
let trimmed_line = if !is_indented {
line
} else if line.len() > config.max_width() {
// If there are lines that are larger than max width, we cannot tell
// whether we have succeeded but have some comments or strings that
// are too long, or we have failed to format code block. We will be
// conservative and just return `None` in this case.
return None;
} else if line.len() > config.tab_spaces() {
// Make sure that the line has leading whitespaces.
let indent_str = Indent::from_width(config, config.tab_spaces()).to_string(config);
if line.starts_with(indent_str.as_ref()) {
let offset = if config.hard_tabs() {
1
} else {
config.tab_spaces()
};
&line[offset..]
} else {
line
}
} else {
line
};
result.push_str(trimmed_line);
is_indented = indent_next_line(kind, line, config);
}
Some(FormattedSnippet {
snippet: result,
non_formatted_ranges: formatted.non_formatted_ranges,
})
}
/// A session is a run of rustfmt across a single or multiple inputs.
pub struct Session<'b, T: Write> {
pub config: Config,
pub out: Option<&'b mut T>,
pub(crate) errors: ReportedErrors,
source_file: SourceFile,
}
impl<'b, T: Write + 'b> Session<'b, T> {
pub fn new(config: Config, out: Option<&'b mut T>) -> Session<'b, T> {
if config.emit_mode() == EmitMode::Checkstyle {
println!("{}", checkstyle::header());
}
Session {
config,
out,
errors: ReportedErrors::default(),
source_file: SourceFile::new(),
}
}
/// The main entry point for Rustfmt. Formats the given input according to the
/// given config. `out` is only necessary if required by the configuration.
pub fn format(&mut self, input: Input) -> Result<FormatReport, ErrorKind> {
self.format_input_inner(input)
}
pub fn override_config<F, U>(&mut self, mut config: Config, f: F) -> U
where
F: FnOnce(&mut Session<'b, T>) -> U,
{
mem::swap(&mut config, &mut self.config);
let result = f(self);
mem::swap(&mut config, &mut self.config);
result
}
pub fn add_operational_error(&mut self) {
self.errors.has_operational_errors = true;
}
pub fn has_operational_errors(&self) -> bool {
self.errors.has_operational_errors
}
pub fn has_parsing_errors(&self) -> bool {
self.errors.has_parsing_errors
}
pub fn has_formatting_errors(&self) -> bool {
self.errors.has_formatting_errors
}
pub fn has_check_errors(&self) -> bool {
self.errors.has_check_errors
}
pub fn has_diff(&self) -> bool {
self.errors.has_diff
}
pub fn has_no_errors(&self) -> bool {
!(self.has_operational_errors()
|| self.has_parsing_errors()
|| self.has_formatting_errors()
|| self.has_check_errors()
|| self.has_diff())
|| self.errors.has_macro_format_failure
}
}
impl<'b, T: Write + 'b> Drop for Session<'b, T> {
fn drop(&mut self) {
if self.config.emit_mode() == EmitMode::Checkstyle {
println!("{}", checkstyle::footer());
}
}
}
#[derive(Debug)]
pub enum Input {
File(PathBuf),
Text(String),
}
impl Input {
fn is_text(&self) -> bool {
match *self {
Input::File(_) => false,
Input::Text(_) => true,
}
}
fn file_name(&self) -> FileName {
match *self {
Input::File(ref file) => FileName::Real(file.clone()),
Input::Text(..) => FileName::Stdin,
}
}
}
#[cfg(test)]
mod unit_tests {
use super::*;
#[test]
fn test_no_panic_on_format_snippet_and_format_code_block() {
// `format_snippet()` and `format_code_block()` should not panic
// even when we cannot parse the given snippet.
let snippet = "let";
assert!(format_snippet(snippet, &Config::default()).is_none());
assert!(format_code_block(snippet, &Config::default()).is_none());
}
fn test_format_inner<F>(formatter: F, input: &str, expected: &str) -> bool
where
F: Fn(&str, &Config) -> Option<FormattedSnippet>,
{
let output = formatter(input, &Config::default());
output.is_some() && output.unwrap().snippet == expected
}
#[test]
fn test_format_snippet() {
let snippet = "fn main() { println!(\"hello, world\"); }";
#[cfg(not(windows))]
let expected = "fn main() {\n \
println!(\"hello, world\");\n\
}\n";
#[cfg(windows)]
let expected = "fn main() {\r\n \
println!(\"hello, world\");\r\n\
}\r\n";
assert!(test_format_inner(format_snippet, snippet, expected));
}
#[test]
fn test_format_code_block_fail() {
#[rustfmt::skip]
let code_block = "this_line_is_100_characters_long_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx(x, y, z);";
assert!(format_code_block(code_block, &Config::default()).is_none());
}
#[test]
fn test_format_code_block() {
// simple code block
let code_block = "let x=3;";
let expected = "let x = 3;";
assert!(test_format_inner(format_code_block, code_block, expected));
// more complex code block, taken from chains.rs.
let code_block =
"let (nested_shape, extend) = if !parent_rewrite_contains_newline && is_continuable(&parent) {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
context.config.indent_style() == IndentStyle::Visual || is_small_parent,
)
} else if is_block_expr(context, &parent, &parent_rewrite) {
match context.config.indent_style() {
// Try to put the first child on the same line with parent's last line
IndentStyle::Block => (parent_shape.block_indent(context.config.tab_spaces()), true),
// The parent is a block, so align the rest of the chain with the closing
// brace.
IndentStyle::Visual => (parent_shape, false),
}
} else {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
false,
)
};
";
let expected =
"let (nested_shape, extend) = if !parent_rewrite_contains_newline && is_continuable(&parent) {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
context.config.indent_style() == IndentStyle::Visual || is_small_parent,
)
} else if is_block_expr(context, &parent, &parent_rewrite) {
match context.config.indent_style() {
// Try to put the first child on the same line with parent's last line
IndentStyle::Block => (parent_shape.block_indent(context.config.tab_spaces()), true),
// The parent is a block, so align the rest of the chain with the closing
// brace.
IndentStyle::Visual => (parent_shape, false),
}
} else {
(
chain_indent(context, shape.add_offset(parent_rewrite.len())),
false,
)
};";
assert!(test_format_inner(format_code_block, code_block, expected));
}
}