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rustfmt_nightly/
utils.rs

1use std::borrow::Cow;
2
3use rustc_ast::YieldKind;
4use rustc_ast::ast::{
5    self, Attribute, ImplRestriction, MetaItem, MetaItemInner, MetaItemKind, MutRestriction,
6    NodeId, Path, RestrictionKind, Visibility, VisibilityKind,
7};
8use rustc_ast_pretty::pprust;
9use rustc_span::{BytePos, LocalExpnId, Span, Symbol, SyntaxContext, sym, symbol};
10use unicode_width::UnicodeWidthStr;
11
12use crate::comment::{CharClasses, FullCodeCharKind, LineClasses, filter_normal_code};
13use crate::config::{Config, StyleEdition};
14use crate::rewrite::RewriteContext;
15use crate::shape::{Indent, Shape};
16
17#[inline]
18pub(crate) fn depr_skip_annotation() -> Symbol {
19    Symbol::intern("rustfmt_skip")
20}
21
22#[inline]
23pub(crate) fn skip_annotation() -> Symbol {
24    Symbol::intern("rustfmt::skip")
25}
26
27pub(crate) fn rewrite_ident<'a>(context: &'a RewriteContext<'_>, ident: symbol::Ident) -> &'a str {
28    context.snippet(ident.span)
29}
30
31// Computes the length of a string's last line, minus offset.
32pub(crate) fn extra_offset(text: &str, shape: Shape) -> usize {
33    match text.rfind('\n') {
34        // 1 for newline character
35        Some(idx) => text.len().saturating_sub(idx + 1 + shape.used_width()),
36        None => text.len(),
37    }
38}
39
40pub(crate) fn is_same_visibility(a: &Visibility, b: &Visibility) -> bool {
41    match (&a.kind, &b.kind) {
42        (
43            VisibilityKind::Restricted { path: p, .. },
44            VisibilityKind::Restricted { path: q, .. },
45        ) => pprust::path_to_string(p) == pprust::path_to_string(q),
46        (VisibilityKind::Public, VisibilityKind::Public)
47        | (VisibilityKind::Inherited, VisibilityKind::Inherited) => true,
48        _ => false,
49    }
50}
51
52// Uses Cow to avoid allocating in the common cases.
53pub(crate) fn format_visibility(
54    context: &RewriteContext<'_>,
55    vis: &Visibility,
56) -> Cow<'static, str> {
57    match vis.kind {
58        VisibilityKind::Public => Cow::from("pub "),
59        VisibilityKind::Inherited => Cow::from(""),
60        VisibilityKind::Restricted { ref path, .. } => {
61            let Path { ref segments, .. } = **path;
62            let mut segments_iter = segments.iter().map(|seg| rewrite_ident(context, seg.ident));
63            if path.is_global() {
64                segments_iter
65                    .next()
66                    .expect("Non-global path in pub(restricted)?");
67            }
68            let is_keyword = |s: &str| s == "crate" || s == "self" || s == "super";
69            let path = segments_iter.collect::<Vec<_>>().join("::");
70            let in_str = if is_keyword(&path) { "" } else { "in " };
71
72            Cow::from(format!("pub({in_str}{path}) "))
73        }
74    }
75}
76
77pub(crate) fn format_impl_restriction(
78    context: &RewriteContext<'_>,
79    impl_restriction: &ImplRestriction,
80) -> String {
81    format_restriction("impl", context, &impl_restriction.kind)
82}
83
84pub(crate) fn format_mut_restriction(
85    context: &RewriteContext<'_>,
86    mut_restriction: &MutRestriction,
87) -> String {
88    format_restriction("mut", context, &mut_restriction.kind)
89}
90
91fn format_restriction(
92    kw: &'static str,
93    context: &RewriteContext<'_>,
94    restriction: &RestrictionKind,
95) -> String {
96    match restriction {
97        RestrictionKind::Unrestricted => String::new(),
98        RestrictionKind::Restricted {
99            ref path,
100            id: _,
101            shorthand,
102        } => {
103            let Path { ref segments, .. } = **path;
104            let mut segments_iter = segments.iter().map(|seg| rewrite_ident(context, seg.ident));
105            if path.is_global() && segments_iter.next().is_none() {
106                panic!("non-global path in {kw}(restricted)?");
107            }
108            // FIXME use `segments_iter.intersperse("::").collect::<String>()` once
109            // `#![feature(iter_intersperse)]` is re-stabilized.
110            let path = itertools::join(segments_iter, "::");
111            let in_str = if *shorthand { "" } else { "in " };
112
113            format!("{kw}({in_str}{path}) ")
114        }
115    }
116}
117
118#[inline]
119pub(crate) fn format_coro(coroutine_kind: &ast::CoroutineKind) -> &'static str {
120    match coroutine_kind {
121        ast::CoroutineKind::Async { .. } => "async ",
122        ast::CoroutineKind::Gen { .. } => "gen ",
123        ast::CoroutineKind::AsyncGen { .. } => "async gen ",
124    }
125}
126
127#[inline]
128pub(crate) fn format_constness(constness: ast::Const) -> &'static str {
129    match constness {
130        ast::Const::Yes(..) => "const ",
131        ast::Const::No => "",
132    }
133}
134
135#[inline]
136pub(crate) fn format_defaultness(defaultness: ast::Defaultness) -> &'static str {
137    match defaultness {
138        ast::Defaultness::Implicit => "",
139        ast::Defaultness::Default(..) => "default ",
140        ast::Defaultness::Final(..) => "final ",
141    }
142}
143
144#[inline]
145pub(crate) fn format_safety(unsafety: ast::Safety) -> &'static str {
146    match unsafety {
147        ast::Safety::Unsafe(..) => "unsafe ",
148        ast::Safety::Safe(..) => "safe ",
149        ast::Safety::Default => "",
150    }
151}
152
153#[inline]
154pub(crate) fn format_auto(is_auto: ast::IsAuto) -> &'static str {
155    match is_auto {
156        ast::IsAuto::Yes => "auto ",
157        ast::IsAuto::No => "",
158    }
159}
160
161#[inline]
162pub(crate) fn format_mutability(mutability: ast::Mutability) -> &'static str {
163    match mutability {
164        ast::Mutability::Mut => "mut ",
165        ast::Mutability::Not => "",
166    }
167}
168
169#[inline]
170pub(crate) fn format_pinnedness_and_mutability(
171    pinnedness: ast::Pinnedness,
172    mutability: ast::Mutability,
173) -> (&'static str, &'static str) {
174    match (pinnedness, mutability) {
175        (ast::Pinnedness::Pinned, ast::Mutability::Mut) => ("pin ", "mut "),
176        (ast::Pinnedness::Pinned, ast::Mutability::Not) => ("pin ", "const "),
177        (ast::Pinnedness::Not, ast::Mutability::Mut) => ("", "mut "),
178        (ast::Pinnedness::Not, ast::Mutability::Not) => ("", ""),
179    }
180}
181
182#[inline]
183pub(crate) fn format_extern(ext: ast::Extern, explicit_abi: bool) -> Cow<'static, str> {
184    match ext {
185        ast::Extern::None => Cow::from(""),
186        ast::Extern::Implicit(_) if explicit_abi => Cow::from("extern \"C\" "),
187        ast::Extern::Implicit(_) => Cow::from("extern "),
188        // turn `extern "C"` into `extern` when `explicit_abi` is set to false
189        ast::Extern::Explicit(abi, _) if abi.symbol_unescaped == sym::C && !explicit_abi => {
190            Cow::from("extern ")
191        }
192        ast::Extern::Explicit(abi, _) => {
193            Cow::from(format!(r#"extern "{}" "#, abi.symbol_unescaped))
194        }
195    }
196}
197
198#[inline]
199// Transform `Vec<Box<T>>` into `Vec<&T>`
200pub(crate) fn ptr_vec_to_ref_vec<T>(vec: &[Box<T>]) -> Vec<&T> {
201    vec.iter().map(|x| &**x).collect::<Vec<_>>()
202}
203
204#[inline]
205pub(crate) fn filter_attributes(
206    attrs: &[ast::Attribute],
207    style: ast::AttrStyle,
208) -> Vec<ast::Attribute> {
209    attrs
210        .iter()
211        .filter(|a| a.style == style)
212        .cloned()
213        .collect::<Vec<_>>()
214}
215
216#[inline]
217pub(crate) fn inner_attributes(attrs: &[ast::Attribute]) -> Vec<ast::Attribute> {
218    filter_attributes(attrs, ast::AttrStyle::Inner)
219}
220
221#[inline]
222pub(crate) fn outer_attributes(attrs: &[ast::Attribute]) -> Vec<ast::Attribute> {
223    filter_attributes(attrs, ast::AttrStyle::Outer)
224}
225
226#[inline]
227pub(crate) fn is_single_line(s: &str) -> bool {
228    !s.chars().any(|c| c == '\n')
229}
230
231#[inline]
232pub(crate) fn first_line_contains_single_line_comment(s: &str) -> bool {
233    s.lines().next().map_or(false, |l| l.contains("//"))
234}
235
236#[inline]
237pub(crate) fn last_line_contains_single_line_comment(s: &str) -> bool {
238    s.lines().last().map_or(false, |l| l.contains("//"))
239}
240
241#[inline]
242pub(crate) fn is_attributes_extendable(attrs_str: &str) -> bool {
243    !attrs_str.contains('\n') && !last_line_contains_single_line_comment(attrs_str)
244}
245
246/// The width of the first line in s.
247#[inline]
248pub(crate) fn first_line_width(s: &str) -> usize {
249    unicode_str_width(s.splitn(2, '\n').next().unwrap_or(""))
250}
251
252/// The width of the last line in s.
253#[inline]
254pub(crate) fn last_line_width(s: &str) -> usize {
255    unicode_str_width(s.rsplitn(2, '\n').next().unwrap_or(""))
256}
257
258/// The total used width of the last line.
259#[inline]
260pub(crate) fn last_line_used_width(s: &str, offset: usize) -> usize {
261    if s.contains('\n') {
262        last_line_width(s)
263    } else {
264        offset + unicode_str_width(s)
265    }
266}
267
268#[inline]
269pub(crate) fn trimmed_last_line_width(s: &str) -> usize {
270    unicode_str_width(match s.rfind('\n') {
271        Some(n) => s[(n + 1)..].trim(),
272        None => s.trim(),
273    })
274}
275
276#[inline]
277pub(crate) fn last_line_extendable(s: &str) -> bool {
278    if s.ends_with("\"#") {
279        return true;
280    }
281    for c in s.chars().rev() {
282        match c {
283            '(' | ')' | ']' | '}' | '?' | '>' => continue,
284            '\n' => break,
285            _ if c.is_whitespace() => continue,
286            _ => return false,
287        }
288    }
289    true
290}
291
292#[inline]
293fn is_skip(meta_item: &MetaItem) -> bool {
294    match meta_item.kind {
295        MetaItemKind::Word => {
296            let path_str = pprust::path_to_string(&meta_item.path);
297            path_str == skip_annotation().as_str() || path_str == depr_skip_annotation().as_str()
298        }
299        MetaItemKind::List(ref l) => {
300            meta_item.has_name(sym::cfg_attr) && l.len() == 2 && is_skip_nested(&l[1])
301        }
302        _ => false,
303    }
304}
305
306#[inline]
307fn is_skip_nested(meta_item: &MetaItemInner) -> bool {
308    match meta_item {
309        MetaItemInner::MetaItem(ref mi) => is_skip(mi),
310        MetaItemInner::Lit(_) => false,
311    }
312}
313
314#[inline]
315pub(crate) fn contains_skip(attrs: &[Attribute]) -> bool {
316    attrs
317        .iter()
318        .any(|a| a.meta().map_or(false, |a| is_skip(&a)))
319}
320
321#[inline]
322pub(crate) fn semicolon_for_expr(context: &RewriteContext<'_>, expr: &ast::Expr) -> bool {
323    // Never try to insert semicolons on expressions when we're inside
324    // a macro definition - this can prevent the macro from compiling
325    // when used in expression position
326    if context.is_macro_def {
327        return false;
328    }
329
330    match expr.kind {
331        ast::ExprKind::Ret(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Break(..) => {
332            context.config.trailing_semicolon()
333        }
334        _ => false,
335    }
336}
337
338#[inline]
339pub(crate) fn semicolon_for_stmt(
340    context: &RewriteContext<'_>,
341    stmt: &ast::Stmt,
342    is_last_expr: bool,
343) -> bool {
344    match stmt.kind {
345        ast::StmtKind::Semi(ref expr) => match expr.kind {
346            ast::ExprKind::While(..) | ast::ExprKind::Loop(..) | ast::ExprKind::ForLoop { .. } => {
347                false
348            }
349            ast::ExprKind::Break(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Ret(..) => {
350                // The only time we can skip the semi-colon is if the config option is set to false
351                // **and** this is the last expr (even though any following exprs are unreachable)
352                context.config.trailing_semicolon() || !is_last_expr
353            }
354            _ => true,
355        },
356        ast::StmtKind::Expr(..) => false,
357        _ => true,
358    }
359}
360
361#[inline]
362pub(crate) fn stmt_expr(stmt: &ast::Stmt) -> Option<&ast::Expr> {
363    match stmt.kind {
364        ast::StmtKind::Expr(ref expr) => Some(expr),
365        _ => None,
366    }
367}
368
369/// Returns the number of LF and CRLF respectively.
370pub(crate) fn count_lf_crlf(input: &str) -> (usize, usize) {
371    let mut lf = 0;
372    let mut crlf = 0;
373    let mut is_crlf = false;
374    for c in input.as_bytes() {
375        match c {
376            b'\r' => is_crlf = true,
377            b'\n' if is_crlf => crlf += 1,
378            b'\n' => lf += 1,
379            _ => is_crlf = false,
380        }
381    }
382    (lf, crlf)
383}
384
385pub(crate) fn count_newlines(input: &str) -> usize {
386    // Using bytes to omit UTF-8 decoding
387    bytecount::count(input.as_bytes(), b'\n')
388}
389
390// For format_missing and last_pos, need to use the source callsite (if applicable).
391// Required as generated code spans aren't guaranteed to follow on from the last span.
392macro_rules! source {
393    ($this:ident, $sp:expr) => {
394        $sp.source_callsite()
395    };
396}
397
398pub(crate) fn mk_sp(lo: BytePos, hi: BytePos) -> Span {
399    Span::new(lo, hi, SyntaxContext::root(), None)
400}
401
402pub(crate) fn mk_sp_lo_plus_one(lo: BytePos) -> Span {
403    Span::new(lo, lo + BytePos(1), SyntaxContext::root(), None)
404}
405
406// Returns `true` if the given span does not intersect with file lines.
407macro_rules! out_of_file_lines_range {
408    ($self:ident, $span:expr) => {
409        !$self.config.file_lines().is_all()
410            && !$self
411                .config
412                .file_lines()
413                .intersects(&$self.psess.lookup_line_range($span))
414    };
415}
416
417macro_rules! skip_out_of_file_lines_range_err {
418    ($self:ident, $span:expr) => {
419        if out_of_file_lines_range!($self, $span) {
420            return Err(RewriteError::SkipFormatting);
421        }
422    };
423}
424
425macro_rules! skip_out_of_file_lines_range_visitor {
426    ($self:ident, $span:expr) => {
427        if out_of_file_lines_range!($self, $span) {
428            $self.push_rewrite($span, None);
429            return;
430        }
431    };
432}
433
434// Wraps String in an Option. Returns Some when the string adheres to the
435// Rewrite constraints defined for the Rewrite trait and None otherwise.
436pub(crate) fn wrap_str(s: String, max_width: usize, shape: Shape) -> Option<String> {
437    if filtered_str_fits(&s, max_width, shape) {
438        Some(s)
439    } else {
440        None
441    }
442}
443
444pub(crate) fn filtered_str_fits(snippet: &str, max_width: usize, shape: Shape) -> bool {
445    let snippet = &filter_normal_code(snippet);
446    if !snippet.is_empty() {
447        // First line must fits with `shape.width`.
448        if first_line_width(snippet) > shape.width {
449            return false;
450        }
451        // If the snippet does not include newline, we are done.
452        if is_single_line(snippet) {
453            return true;
454        }
455        // The other lines must fit within the maximum width.
456        if snippet
457            .lines()
458            .skip(1)
459            .any(|line| unicode_str_width(line) > max_width)
460        {
461            return false;
462        }
463        // A special check for the last line, since the caller may
464        // place trailing characters on this line.
465        if last_line_width(snippet) > shape.used_width() + shape.width {
466            return false;
467        }
468    }
469    true
470}
471
472#[inline]
473pub(crate) fn colon_spaces(config: &Config) -> &'static str {
474    let before = config.space_before_colon();
475    let after = config.space_after_colon();
476    match (before, after) {
477        (true, true) => " : ",
478        (true, false) => " :",
479        (false, true) => ": ",
480        (false, false) => ":",
481    }
482}
483
484#[inline]
485pub(crate) fn left_most_sub_expr(e: &ast::Expr) -> &ast::Expr {
486    match e.kind {
487        ast::ExprKind::Call(ref e, _)
488        | ast::ExprKind::Binary(_, ref e, _)
489        | ast::ExprKind::Cast(ref e, _)
490        | ast::ExprKind::Type(ref e, _)
491        | ast::ExprKind::Assign(ref e, _, _)
492        | ast::ExprKind::AssignOp(_, ref e, _)
493        | ast::ExprKind::Field(ref e, _)
494        | ast::ExprKind::Index(ref e, _, _)
495        | ast::ExprKind::Range(Some(ref e), _, _)
496        | ast::ExprKind::Try(ref e) => left_most_sub_expr(e),
497        _ => e,
498    }
499}
500
501#[inline]
502pub(crate) fn starts_with_newline(s: &str) -> bool {
503    s.starts_with('\n') || s.starts_with("\r\n")
504}
505
506#[inline]
507pub(crate) fn first_line_ends_with(s: &str, c: char) -> bool {
508    s.lines().next().map_or(false, |l| l.ends_with(c))
509}
510
511// States whether an expression's last line exclusively consists of closing
512// parens, braces, and brackets in its idiomatic formatting.
513pub(crate) fn is_block_expr(context: &RewriteContext<'_>, expr: &ast::Expr, repr: &str) -> bool {
514    match expr.kind {
515        ast::ExprKind::MacCall(..)
516        | ast::ExprKind::FormatArgs(..)
517        | ast::ExprKind::Call(..)
518        | ast::ExprKind::MethodCall(..)
519        | ast::ExprKind::Array(..)
520        | ast::ExprKind::Struct(..)
521        | ast::ExprKind::While(..)
522        | ast::ExprKind::If(..)
523        | ast::ExprKind::Block(..)
524        | ast::ExprKind::ConstBlock(..)
525        | ast::ExprKind::Gen(..)
526        | ast::ExprKind::Loop(..)
527        | ast::ExprKind::ForLoop { .. }
528        | ast::ExprKind::TryBlock(..)
529        | ast::ExprKind::Match(..) => repr.contains('\n'),
530        ast::ExprKind::Paren(ref expr)
531        | ast::ExprKind::Binary(_, _, ref expr)
532        | ast::ExprKind::Index(_, ref expr, _)
533        | ast::ExprKind::Unary(_, ref expr)
534        | ast::ExprKind::Try(ref expr)
535        | ast::ExprKind::Yield(YieldKind::Prefix(Some(ref expr))) => {
536            is_block_expr(context, expr, repr)
537        }
538        ast::ExprKind::Closure(ref closure) => is_block_expr(context, &closure.body, repr),
539        // This can only be a string lit
540        ast::ExprKind::Lit(_) => {
541            repr.contains('\n') && trimmed_last_line_width(repr) <= context.config.tab_spaces()
542        }
543        ast::ExprKind::AddrOf(..)
544        | ast::ExprKind::Assign(..)
545        | ast::ExprKind::AssignOp(..)
546        | ast::ExprKind::Await(..)
547        | ast::ExprKind::Break(..)
548        | ast::ExprKind::Cast(..)
549        | ast::ExprKind::Continue(..)
550        | ast::ExprKind::Dummy
551        | ast::ExprKind::Err(_)
552        | ast::ExprKind::Field(..)
553        | ast::ExprKind::IncludedBytes(..)
554        | ast::ExprKind::InlineAsm(..)
555        | ast::ExprKind::Move(..)
556        | ast::ExprKind::OffsetOf(..)
557        | ast::ExprKind::UnsafeBinderCast(..)
558        | ast::ExprKind::Let(..)
559        | ast::ExprKind::Path(..)
560        | ast::ExprKind::Range(..)
561        | ast::ExprKind::Repeat(..)
562        | ast::ExprKind::Ret(..)
563        | ast::ExprKind::Become(..)
564        | ast::ExprKind::Yeet(..)
565        | ast::ExprKind::Tup(..)
566        | ast::ExprKind::Use(..)
567        | ast::ExprKind::Type(..)
568        | ast::ExprKind::Yield(..)
569        | ast::ExprKind::Underscore => false,
570    }
571}
572
573/// Removes trailing spaces from the specified snippet. We do not remove spaces
574/// inside strings or comments.
575pub(crate) fn remove_trailing_white_spaces(text: &str) -> String {
576    let mut buffer = String::with_capacity(text.len());
577    let mut space_buffer = String::with_capacity(128);
578    for (char_kind, c) in CharClasses::new(text.chars()) {
579        match c {
580            '\n' => {
581                if char_kind == FullCodeCharKind::InString {
582                    buffer.push_str(&space_buffer);
583                }
584                space_buffer.clear();
585                buffer.push('\n');
586            }
587            _ if c.is_whitespace() => {
588                space_buffer.push(c);
589            }
590            _ => {
591                if !space_buffer.is_empty() {
592                    buffer.push_str(&space_buffer);
593                    space_buffer.clear();
594                }
595                buffer.push(c);
596            }
597        }
598    }
599    buffer
600}
601
602/// Indent each line according to the specified `indent`.
603/// e.g.
604///
605/// ```rust,compile_fail
606/// foo!{
607/// x,
608/// y,
609/// foo(
610///     a,
611///     b,
612///     c,
613/// ),
614/// }
615/// ```
616///
617/// will become
618///
619/// ```rust,compile_fail
620/// foo!{
621///     x,
622///     y,
623///     foo(
624///         a,
625///         b,
626///         c,
627///     ),
628/// }
629/// ```
630pub(crate) fn trim_left_preserve_layout(
631    orig: &str,
632    indent: Indent,
633    config: &Config,
634) -> Option<String> {
635    let mut lines = LineClasses::new(orig);
636    let first_line = lines.next().map(|(_, s)| s.trim_end().to_owned())?;
637    let mut trimmed_lines = Vec::with_capacity(16);
638
639    let mut veto_trim = false;
640    let min_prefix_space_width = lines
641        .filter_map(|(kind, line)| {
642            let mut trimmed = true;
643            let prefix_space_width = if is_empty_line(&line) {
644                None
645            } else {
646                Some(get_prefix_space_width(config, &line))
647            };
648
649            // just InString{Commented} in order to allow the start of a string to be indented
650            let new_veto_trim_value = (kind == FullCodeCharKind::InString
651                || (config.style_edition() >= StyleEdition::Edition2024
652                    && kind == FullCodeCharKind::InStringCommented))
653                && !line.ends_with('\\');
654            let line = if veto_trim || new_veto_trim_value {
655                veto_trim = new_veto_trim_value;
656                trimmed = false;
657                line
658            } else {
659                line.trim().to_owned()
660            };
661            trimmed_lines.push((trimmed, line, prefix_space_width));
662
663            // Because there is a veto against trimming and indenting lines within a string,
664            // such lines should not be taken into account when computing the minimum.
665            match kind {
666                FullCodeCharKind::InStringCommented | FullCodeCharKind::EndStringCommented
667                    if config.style_edition() >= StyleEdition::Edition2024 =>
668                {
669                    None
670                }
671                FullCodeCharKind::InString | FullCodeCharKind::EndString => None,
672                _ => prefix_space_width,
673            }
674        })
675        .min()?;
676
677    Some(
678        first_line
679            + "\n"
680            + &trimmed_lines
681                .iter()
682                .map(
683                    |&(trimmed, ref line, prefix_space_width)| match prefix_space_width {
684                        _ if !trimmed => line.to_owned(),
685                        Some(original_indent_width) => {
686                            let new_indent_width = indent.width()
687                                + original_indent_width.saturating_sub(min_prefix_space_width);
688                            let new_indent = Indent::from_width(config, new_indent_width);
689                            format!("{}{}", new_indent.to_string(config), line)
690                        }
691                        None => String::new(),
692                    },
693                )
694                .collect::<Vec<_>>()
695                .join("\n"),
696    )
697}
698
699/// Based on the given line, determine if the next line can be indented or not.
700/// This allows to preserve the indentation of multi-line literals when
701/// re-inserted a code block that has been formatted separately from the rest
702/// of the code, such as code in macro defs or code blocks doc comments.
703pub(crate) fn indent_next_line(kind: FullCodeCharKind, line: &str, config: &Config) -> bool {
704    if kind.is_string() {
705        // If the string ends with '\', the string has been wrapped over
706        // multiple lines. If `format_strings = true`, then the indentation of
707        // strings wrapped over multiple lines will have been adjusted while
708        // formatting the code block, therefore the string's indentation needs
709        // to be adjusted for the code surrounding the code block.
710        config.format_strings() && line.ends_with('\\')
711    } else if config.style_edition() >= StyleEdition::Edition2024 {
712        !kind.is_commented_string()
713    } else {
714        true
715    }
716}
717
718pub(crate) fn is_empty_line(s: &str) -> bool {
719    s.is_empty() || s.chars().all(char::is_whitespace)
720}
721
722fn get_prefix_space_width(config: &Config, s: &str) -> usize {
723    let mut width = 0;
724    for c in s.chars() {
725        match c {
726            ' ' => width += 1,
727            '\t' => width += config.tab_spaces(),
728            _ => return width,
729        }
730    }
731    width
732}
733
734pub(crate) trait NodeIdExt {
735    fn root() -> Self;
736}
737
738impl NodeIdExt for NodeId {
739    fn root() -> NodeId {
740        NodeId::placeholder_from_expn_id(LocalExpnId::ROOT)
741    }
742}
743
744pub(crate) fn unicode_str_width(s: &str) -> usize {
745    s.width()
746}
747
748#[cfg(test)]
749mod test {
750    use super::*;
751
752    #[test]
753    fn test_remove_trailing_white_spaces() {
754        let s = "    r#\"\n        test\n    \"#";
755        assert_eq!(remove_trailing_white_spaces(s), s);
756    }
757
758    #[test]
759    fn test_trim_left_preserve_layout() {
760        let s = "aaa\n\tbbb\n    ccc";
761        let config = Config::default();
762        let indent = Indent::new(4, 0);
763        assert_eq!(
764            trim_left_preserve_layout(s, indent, &config),
765            Some("aaa\n    bbb\n    ccc".to_string())
766        );
767    }
768}