1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
#![feature(rustc_private)]
#![deny(rust_2018_idioms)]
#![warn(unreachable_pub)]
#![recursion_limit = "256"]
#![allow(clippy::match_like_matches_macro)]
#![allow(unreachable_pub)]

#[cfg(test)]
#[macro_use]
extern crate lazy_static;
#[macro_use]
extern crate log;

// N.B. these crates are loaded from the sysroot, so they need extern crate.
extern crate rustc_ast;
extern crate rustc_ast_pretty;
extern crate rustc_builtin_macros;
extern crate rustc_data_structures;
extern crate rustc_errors;
extern crate rustc_expand;
extern crate rustc_parse;
extern crate rustc_session;
extern crate rustc_span;
extern crate thin_vec;

// Necessary to pull in object code as the rest of the rustc crates are shipped only as rmeta
// files.
#[allow(unused_extern_crates)]
extern crate rustc_driver;

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 rustc_ast::ast;
use rustc_span::symbol;
use thiserror::Error;

use crate::comment::LineClasses;
use crate::emitter::Emitter;
use crate::formatting::{FormatErrorMap, FormattingError, ReportedErrors, SourceFile};
use crate::modules::ModuleResolutionError;
use crate::parse::parser::DirectoryOwnership;
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,
};

pub use crate::format_report_formatter::{FormatReportFormatter, FormatReportFormatterBuilder};

pub use crate::rustfmt_diff::{ModifiedChunk, ModifiedLines};

#[macro_use]
mod utils;

mod attr;
mod chains;
mod closures;
mod comment;
pub(crate) mod config;
mod coverage;
mod emitter;
mod expr;
mod format_report_formatter;
pub(crate) mod formatting;
mod ignore_path;
mod imports;
mod items;
mod lists;
mod macros;
mod matches;
mod missed_spans;
pub(crate) mod modules;
mod overflow;
mod pairs;
mod parse;
mod patterns;
mod release_channel;
mod reorder;
mod rewrite;
pub(crate) mod rustfmt_diff;
mod shape;
mod skip;
pub(crate) mod source_file;
pub(crate) mod source_map;
mod spanned;
mod stmt;
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(Error, Debug)]
pub enum ErrorKind {
    /// Line has exceeded character limit (found, maximum).
    #[error(
        "line formatted, but exceeded maximum width \
         (maximum: {1} (see `max_width` option), found: {0})"
    )]
    LineOverflow(usize, usize),
    /// Line ends in whitespace.
    #[error("left behind trailing whitespace")]
    TrailingWhitespace,
    /// Used deprecated skip attribute.
    #[error("`rustfmt_skip` is deprecated; use `rustfmt::skip`")]
    DeprecatedAttr,
    /// Used a rustfmt:: attribute other than skip or skip::macros.
    #[error("invalid attribute")]
    BadAttr,
    /// An io error during reading or writing.
    #[error("io error: {0}")]
    IoError(io::Error),
    /// Error during module resolution.
    #[error("{0}")]
    ModuleResolutionError(#[from] ModuleResolutionError),
    /// Parse error occurred when parsing the input.
    #[error("parse error")]
    ParseError,
    /// The user mandated a version and the current version of Rustfmt does not
    /// satisfy that requirement.
    #[error("version mismatch")]
    VersionMismatch,
    /// If we had formatted the given node, then we would have lost a comment.
    #[error("not formatted because a comment would be lost")]
    LostComment,
    /// Invalid glob pattern in `ignore` configuration option.
    #[error("Invalid glob pattern found in ignore list: {0}")]
    InvalidGlobPattern(ignore::Error),
}

impl ErrorKind {
    fn is_comment(&self) -> bool {
        matches!(self, ErrorKind::LostComment)
    }
}

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 using the `Display` impl on [`FormatReportFormatter`].
#[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 && errs.has_unformatted_code_errors
        {
            return;
        }
        for err in new_errors {
            match err.kind {
                ErrorKind::LineOverflow(..) => {
                    errs.has_operational_errors = true;
                }
                ErrorKind::TrailingWhitespace => {
                    errs.has_operational_errors = true;
                    errs.has_unformatted_code_errors = true;
                }
                ErrorKind::LostComment => {
                    errs.has_unformatted_code_errors = true;
                }
                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.
    #[deprecated(note = "Use FormatReportFormatter with colors enabled instead")]
    pub fn fancy_print(
        &self,
        mut t: Box<dyn term::Terminal<Output = io::Stderr>>,
    ) -> Result<(), term::Error> {
        writeln!(
            t,
            "{}",
            FormatReportFormatterBuilder::new(self)
                .enable_colors(true)
                .build()
        )?;
        Ok(())
    }
}

/// Deprecated - Use FormatReportFormatter instead
// https://github.com/rust-lang/rust/issues/78625
// https://github.com/rust-lang/rust/issues/39935
impl fmt::Display for FormatReport {
    // Prints all the formatting errors.
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
        write!(fmt, "{}", FormatReportFormatterBuilder::new(self).build())?;
        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, is_macro_def: bool) -> 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);
        if is_macro_def {
            config.set().error_on_unformatted(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_inner(input, is_macro_def);
            (
                session.errors.has_macro_format_failure
                    || session.out.as_ref().unwrap().is_empty() && !snippet.is_empty()
                    || result.is_err()
                    || (is_macro_def && session.has_unformatted_code_errors()),
                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,
    is_macro_def: bool,
) -> 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, is_macro_def)?;
    // 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_else(|| formatted.snippet.len());
    let mut is_indented = true;
    let indent_str = Indent::from_width(config, config.tab_spaces()).to_string(config);
    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() > indent_str.len() {
            // Make sure that the line has leading whitespaces.
            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,
    emitter: Box<dyn Emitter + 'b>,
}

impl<'b, T: Write + 'b> Session<'b, T> {
    pub fn new(config: Config, mut out: Option<&'b mut T>) -> Session<'b, T> {
        let emitter = create_emitter(&config);

        if let Some(ref mut out) = out {
            let _ = emitter.emit_header(out);
        }

        Session {
            config,
            out,
            emitter,
            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, false)
    }

    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_unformatted_code_errors(&self) -> bool {
        self.errors.has_unformatted_code_errors
    }

    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.has_unformatted_code_errors()
            || self.errors.has_macro_format_failure)
    }
}

pub(crate) fn create_emitter<'a>(config: &Config) -> Box<dyn Emitter + 'a> {
    match config.emit_mode() {
        EmitMode::Files if config.make_backup() => {
            Box::new(emitter::FilesWithBackupEmitter::default())
        }
        EmitMode::Files => Box::new(emitter::FilesEmitter::new(
            config.print_misformatted_file_names(),
        )),
        EmitMode::Stdout | EmitMode::Coverage => {
            Box::new(emitter::StdoutEmitter::new(config.verbose()))
        }
        EmitMode::Json => Box::new(emitter::JsonEmitter::default()),
        EmitMode::ModifiedLines => Box::new(emitter::ModifiedLinesEmitter::default()),
        EmitMode::Checkstyle => Box::new(emitter::CheckstyleEmitter::default()),
        EmitMode::Diff => Box::new(emitter::DiffEmitter::new(config.clone())),
    }
}

impl<'b, T: Write + 'b> Drop for Session<'b, T> {
    fn drop(&mut self) {
        if let Some(ref mut out) = self.out {
            let _ = self.emitter.emit_footer(out);
        }
    }
}

#[derive(Debug)]
pub enum Input {
    File(PathBuf),
    Text(String),
}

impl Input {
    fn file_name(&self) -> FileName {
        match *self {
            Input::File(ref file) => FileName::Real(file.clone()),
            Input::Text(..) => FileName::Stdin,
        }
    }

    fn to_directory_ownership(&self) -> Option<DirectoryOwnership> {
        match self {
            Input::File(ref file) => {
                // If there exists a directory with the same name as an input,
                // then the input should be parsed as a sub module.
                let file_stem = file.file_stem()?;
                if file.parent()?.to_path_buf().join(file_stem).is_dir() {
                    Some(DirectoryOwnership::Owned {
                        relative: file_stem.to_str().map(symbol::Ident::from_str),
                    })
                } else {
                    None
                }
            }
            _ => None,
        }
    }
}

#[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(), false).is_none());
        assert!(format_code_block(snippet, &Config::default(), false).is_none());
    }

    fn test_format_inner<F>(formatter: F, input: &str, expected: &str) -> bool
    where
        F: Fn(&str, &Config, bool) -> Option<FormattedSnippet>,
    {
        let output = formatter(input, &Config::default(), false);
        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(), false).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));
    }
}