1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // Formatting top-level items - functions, structs, enums, traits, impls.
14 use std::cmp::{min, Ordering};
18 use rustc_target::spec::abi;
19 use syntax::codemap::{self, BytePos, Span};
21 use syntax::{ast, ptr, symbol};
23 use codemap::{LineRangeUtils, SpanUtils};
25 combine_strs_with_missing_comments, contains_comment, recover_comment_removed,
26 recover_missing_comment_in_span, rewrite_missing_comment, FindUncommented,
28 use config::{BraceStyle, Config, Density, IndentStyle};
30 format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs, rewrite_assign_rhs_with,
33 use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, ListItem, Separator};
34 use macros::{rewrite_macro, MacroPosition};
36 use rewrite::{Rewrite, RewriteContext};
37 use shape::{Indent, Shape};
39 use types::TraitTyParamBounds;
41 use vertical::rewrite_with_alignment;
42 use visitor::FmtVisitor;
44 const DEFAULT_VISIBILITY: ast::Visibility = codemap::Spanned {
45 node: ast::VisibilityKind::Inherited,
46 span: codemap::DUMMY_SP,
49 fn type_annotation_separator(config: &Config) -> &str {
50 colon_spaces(config.space_before_colon(), config.space_after_colon())
53 // Statements of the form
54 // let pat: ty = init;
55 impl Rewrite for ast::Local {
56 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
58 "Local::rewrite {:?} {} {:?}",
59 self, shape.width, shape.indent
62 skip_out_of_file_lines_range!(context, self.span);
64 if contains_skip(&self.attrs) {
68 let attrs_str = self.attrs.rewrite(context, shape)?;
69 let mut result = if attrs_str.is_empty() {
72 combine_strs_with_missing_comments(
77 self.attrs.last().map(|a| a.span.hi()).unwrap(),
86 let pat_shape = shape.offset_left(4)?;
88 let pat_shape = pat_shape.sub_width(1)?;
89 let pat_str = self.pat.rewrite(context, pat_shape)?;
90 result.push_str(&pat_str);
92 // String that is placed within the assignment pattern and expression.
94 let mut infix = String::with_capacity(32);
96 if let Some(ref ty) = self.ty {
97 let separator = type_annotation_separator(context.config);
98 let indent = shape.indent + last_line_width(&result) + separator.len();
100 let budget = shape.width.checked_sub(indent.width() + 1)?;
101 let rewrite = ty.rewrite(context, Shape::legacy(budget, indent))?;
103 infix.push_str(separator);
104 infix.push_str(&rewrite);
107 if self.init.is_some() {
108 infix.push_str(" =");
114 result.push_str(&infix);
116 if let Some(ref ex) = self.init {
117 // 1 = trailing semicolon;
118 let nested_shape = shape.sub_width(1)?;
120 result = rewrite_assign_rhs(context, result, &**ex, nested_shape)?;
128 // TODO convert to using rewrite style rather than visitor
129 // TODO format modules in this style
132 keyword: &'static str,
133 abi: Cow<'static, str>,
134 vis: Option<&'a ast::Visibility>,
135 body: Vec<BodyElement<'a>>,
140 fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Item<'a> {
143 abi: format_abi(fm.abi, config.force_explicit_abi(), true),
148 .map(|i| BodyElement::ForeignItem(i))
155 enum BodyElement<'a> {
156 // Stmt(&'a ast::Stmt),
157 // Field(&'a ast::Field),
158 // Variant(&'a ast::Variant),
159 // Item(&'a ast::Item),
160 ForeignItem(&'a ast::ForeignItem),
163 /// Represents a fn's signature.
164 pub struct FnSig<'a> {
165 decl: &'a ast::FnDecl,
166 generics: &'a ast::Generics,
168 constness: ast::Constness,
169 defaultness: ast::Defaultness,
170 unsafety: ast::Unsafety,
171 visibility: ast::Visibility,
176 decl: &'a ast::FnDecl,
177 generics: &'a ast::Generics,
178 vis: ast::Visibility,
184 constness: ast::Constness::NotConst,
185 defaultness: ast::Defaultness::Final,
186 unsafety: ast::Unsafety::Normal,
191 pub fn from_method_sig(
192 method_sig: &'a ast::MethodSig,
193 generics: &'a ast::Generics,
196 unsafety: method_sig.unsafety,
197 constness: method_sig.constness.node,
198 defaultness: ast::Defaultness::Final,
200 decl: &*method_sig.decl,
202 visibility: DEFAULT_VISIBILITY,
207 fn_kind: &'a visit::FnKind,
208 generics: &'a ast::Generics,
209 decl: &'a ast::FnDecl,
210 defaultness: ast::Defaultness,
213 visit::FnKind::ItemFn(_, unsafety, constness, abi, visibility, _) => FnSig {
217 constness: constness.node,
220 visibility: visibility.clone(),
222 visit::FnKind::Method(_, method_sig, vis, _) => {
223 let mut fn_sig = FnSig::from_method_sig(method_sig, generics);
224 fn_sig.defaultness = defaultness;
225 if let Some(vis) = vis {
226 fn_sig.visibility = vis.clone();
234 fn to_str(&self, context: &RewriteContext) -> String {
235 let mut result = String::with_capacity(128);
236 // Vis defaultness constness unsafety abi.
237 result.push_str(&*format_visibility(&self.visibility));
238 result.push_str(format_defaultness(self.defaultness));
239 result.push_str(format_constness(self.constness));
240 result.push_str(format_unsafety(self.unsafety));
241 result.push_str(&format_abi(
243 context.config.force_explicit_abi(),
250 impl<'a> FmtVisitor<'a> {
251 fn format_item(&mut self, item: &Item) {
252 self.buffer.push_str(&item.abi);
254 let snippet = self.snippet(item.span);
255 let brace_pos = snippet.find_uncommented("{").unwrap();
258 if !item.body.is_empty() || contains_comment(&snippet[brace_pos..]) {
259 // FIXME: this skips comments between the extern keyword and the opening
261 self.last_pos = item.span.lo() + BytePos(brace_pos as u32 + 1);
262 self.block_indent = self.block_indent.block_indent(self.config);
264 if item.body.is_empty() {
265 self.format_missing_no_indent(item.span.hi() - BytePos(1));
266 self.block_indent = self.block_indent.block_unindent(self.config);
267 let indent_str = self.block_indent.to_string(self.config);
268 self.push_str(&indent_str);
270 for item in &item.body {
271 self.format_body_element(item);
274 self.block_indent = self.block_indent.block_unindent(self.config);
275 self.format_missing_with_indent(item.span.hi() - BytePos(1));
280 self.last_pos = item.span.hi();
283 fn format_body_element(&mut self, element: &BodyElement) {
285 BodyElement::ForeignItem(item) => self.format_foreign_item(item),
289 pub fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) {
290 let item = Item::from_foreign_mod(fm, span, self.config);
291 self.format_item(&item);
294 fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
295 let rewrite = item.rewrite(&self.get_context(), self.shape());
296 self.push_rewrite(item.span(), rewrite);
297 self.last_pos = item.span.hi();
307 inner_attrs: Option<&[ast::Attribute]>,
308 ) -> Option<String> {
309 let context = self.get_context();
311 let mut newline_brace = newline_for_brace(self.config, &fn_sig.generics.where_clause);
313 let (mut result, force_newline_brace) =
314 rewrite_fn_base(&context, indent, ident, fn_sig, span, newline_brace, true)?;
317 if self.config.brace_style() == BraceStyle::AlwaysNextLine
318 || force_newline_brace
319 || last_line_width(&result) + 2 > self.shape().width
321 newline_brace = true;
322 } else if !result.contains('\n') {
323 newline_brace = false;
326 // Prepare for the function body by possibly adding a newline and
328 // FIXME we'll miss anything between the end of the signature and the
329 // start of the body, but we need more spans from the compiler to solve
332 result.push_str(&indent.to_string_with_newline(self.config));
337 self.single_line_fn(&result, block, inner_attrs)
338 .or_else(|| Some(result))
341 pub fn rewrite_required_fn(
345 sig: &ast::MethodSig,
346 generics: &ast::Generics,
348 ) -> Option<String> {
349 // Drop semicolon or it will be interpreted as comment.
350 let span = mk_sp(span.lo(), span.hi() - BytePos(1));
351 let context = self.get_context();
353 let (mut result, _) = rewrite_fn_base(
357 &FnSig::from_method_sig(sig, generics),
363 // Re-attach semicolon
373 inner_attrs: Option<&[ast::Attribute]>,
374 ) -> Option<String> {
375 if fn_str.contains('\n') || inner_attrs.map_or(false, |a| !a.is_empty()) {
379 let codemap = self.get_context().codemap;
381 if self.config.empty_item_single_line()
382 && is_empty_block(block, None, codemap)
383 && self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width()
385 return Some(format!("{}{{}}", fn_str));
388 if self.config.fn_single_line() && is_simple_block_stmt(block, None, codemap) {
390 if let Some(stmt) = block.stmts.first() {
391 match stmt_expr(stmt) {
393 let suffix = if semicolon_for_expr(&self.get_context(), e) {
399 format_expr(e, ExprType::Statement, &self.get_context(), self.shape())
401 .or_else(|| Some(self.snippet(e.span).to_owned()))
403 None => stmt.rewrite(&self.get_context(), self.shape()),
410 if let Some(res) = rewrite {
411 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
412 if !res.contains('\n') && width <= self.config.max_width() {
413 return Some(format!("{}{{ {} }}", fn_str, res));
421 pub fn visit_static(&mut self, static_parts: &StaticParts) {
422 let rewrite = rewrite_static(&self.get_context(), static_parts, self.block_indent);
423 self.push_rewrite(static_parts.span, rewrite);
426 pub fn visit_struct(&mut self, struct_parts: &StructParts) {
427 let is_tuple = struct_parts.def.is_tuple();
428 let rewrite = format_struct(&self.get_context(), struct_parts, self.block_indent, None)
429 .map(|s| if is_tuple { s + ";" } else { s });
430 self.push_rewrite(struct_parts.span, rewrite);
436 vis: &ast::Visibility,
437 enum_def: &ast::EnumDef,
438 generics: &ast::Generics,
441 let enum_header = format_header("enum ", ident, vis);
442 self.push_str(&enum_header);
444 let enum_snippet = self.snippet(span);
445 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
446 let body_start = span.lo() + BytePos(brace_pos as u32 + 1);
447 let generics_str = format_generics(
450 self.config.brace_style(),
451 if enum_def.variants.is_empty() {
452 BracePos::ForceSameLine
457 mk_sp(span.lo(), body_start),
458 last_line_width(&enum_header),
460 self.push_str(&generics_str);
462 self.last_pos = body_start;
464 match self.format_variant_list(enum_def, body_start, span.hi()) {
465 Some(ref s) if enum_def.variants.is_empty() => self.push_str(s),
467 self.push_rewrite(mk_sp(body_start, span.hi()), rw);
468 self.block_indent = self.block_indent.block_unindent(self.config);
473 // Format the body of an enum definition
474 fn format_variant_list(
476 enum_def: &ast::EnumDef,
479 ) -> Option<String> {
480 if enum_def.variants.is_empty() {
481 let mut buffer = String::with_capacity(128);
483 let span = mk_sp(body_lo, body_hi - BytePos(1));
484 format_empty_struct_or_tuple(
494 let mut result = String::with_capacity(1024);
495 let original_offset = self.block_indent;
496 self.block_indent = self.block_indent.block_indent(self.config);
498 let itemize_list_with = |one_line_width: usize| {
500 self.snippet_provider,
501 enum_def.variants.iter(),
505 if !f.node.attrs.is_empty() {
506 f.node.attrs[0].span.lo()
512 |f| self.format_variant(f, one_line_width),
518 let mut items: Vec<_> =
519 itemize_list_with(self.config.width_heuristics().struct_variant_width);
520 // If one of the variants use multiple lines, use multi-lined formatting for all variants.
521 let has_multiline_variant = items.iter().any(|item| item.inner_as_ref().contains('\n'));
522 let has_single_line_variant = items.iter().any(|item| !item.inner_as_ref().contains('\n'));
523 if has_multiline_variant && has_single_line_variant {
524 items = itemize_list_with(0);
527 let shape = self.shape().sub_width(2)?;
528 let fmt = ListFormatting {
529 tactic: DefinitiveListTactic::Vertical,
531 trailing_separator: self.config.trailing_comma(),
532 separator_place: SeparatorPlace::Back,
534 ends_with_newline: true,
535 preserve_newline: true,
539 let list = write_list(&items, &fmt)?;
540 result.push_str(&list);
541 result.push_str(&original_offset.to_string_with_newline(self.config));
546 // Variant of an enum.
547 fn format_variant(&self, field: &ast::Variant, one_line_width: usize) -> Option<String> {
548 if contains_skip(&field.node.attrs) {
549 let lo = field.node.attrs[0].span.lo();
550 let span = mk_sp(lo, field.span.hi());
551 return Some(self.snippet(span).to_owned());
554 let context = self.get_context();
556 let shape = self.shape().sub_width(1)?;
557 let attrs_str = field.node.attrs.rewrite(&context, shape)?;
562 .map_or(field.span.lo(), |attr| attr.span.hi());
563 let span = mk_sp(lo, field.span.lo());
565 let variant_body = match field.node.data {
566 ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => format_struct(
568 &StructParts::from_variant(field),
570 Some(one_line_width),
572 ast::VariantData::Unit(..) => {
573 if let Some(ref expr) = field.node.disr_expr {
574 let lhs = format!("{} =", field.node.ident.name);
575 rewrite_assign_rhs(&context, lhs, &*expr.value, shape)?
577 field.node.ident.name.to_string()
582 combine_strs_with_missing_comments(&context, &attrs_str, &variant_body, span, shape, false)
585 fn visit_impl_items(&mut self, items: &[ast::ImplItem]) {
586 if self.get_context().config.reorder_impl_items() {
587 // Create visitor for each items, then reorder them.
588 let mut buffer = vec![];
590 self.visit_impl_item(item);
591 buffer.push((self.buffer.clone(), item.clone()));
594 // type -> const -> macro -> method
595 use ast::ImplItemKind::*;
596 fn need_empty_line(a: &ast::ImplItemKind, b: &ast::ImplItemKind) -> bool {
598 (Type(..), Type(..)) | (Const(..), Const(..)) => false,
603 buffer.sort_by(|(_, a), (_, b)| match (&a.node, &b.node) {
604 (Type(..), _) => Ordering::Less,
605 (_, Type(..)) => Ordering::Greater,
606 (Const(..), _) => Ordering::Less,
607 (_, Const(..)) => Ordering::Greater,
608 (Macro(..), _) => Ordering::Less,
609 (_, Macro(..)) => Ordering::Greater,
610 _ => a.span.lo().cmp(&b.span.lo()),
612 let mut prev_kind = None;
613 for (buf, item) in buffer {
614 // Make sure that there are at least a single empty line between
615 // different impl items.
618 .map_or(false, |prev_kind| need_empty_line(prev_kind, &item.node))
622 let indent_str = self.block_indent.to_string_with_newline(self.config);
623 self.push_str(&indent_str);
624 self.push_str(buf.trim());
625 prev_kind = Some(item.node.clone());
629 self.visit_impl_item(item);
636 context: &RewriteContext,
639 where_span_end: Option<BytePos>,
640 ) -> Option<String> {
641 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
642 let mut result = String::with_capacity(128);
643 let ref_and_type = format_impl_ref_and_type(context, item, offset)?;
644 let sep = offset.to_string_with_newline(context.config);
645 result.push_str(&ref_and_type);
647 let where_budget = if result.contains('\n') {
648 context.config.max_width()
650 context.budget(last_line_width(&result))
653 let mut option = WhereClauseOption::snuggled(&ref_and_type);
654 let snippet = context.snippet(item.span);
655 let open_pos = snippet.find_uncommented("{")? + 1;
656 if !contains_comment(&snippet[open_pos..])
658 && generics.where_clause.predicates.len() == 1
660 option.suppress_comma();
662 option.compress_where();
665 let mut where_clause_str = rewrite_where_clause(
667 &generics.where_clause,
668 context.config.brace_style(),
669 Shape::legacy(where_budget, offset.block_only()),
678 // If there is no where clause, we may have missing comments between the trait name and
679 // the opening brace.
680 if generics.where_clause.predicates.is_empty() {
681 if let Some(hi) = where_span_end {
682 match recover_missing_comment_in_span(
683 mk_sp(self_ty.span.hi(), hi),
684 Shape::indented(offset, context.config),
686 last_line_width(&result),
688 Some(ref missing_comment) if !missing_comment.is_empty() => {
689 result.push_str(missing_comment);
696 if is_impl_single_line(context, items, &result, &where_clause_str, item)? {
697 result.push_str(&where_clause_str);
698 if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
699 // if the where_clause contains extra comments AND there is only one where clause predicate
700 // recover the suppressed comma in single line where_clause formatting
701 if generics.where_clause.predicates.len() == 1 {
702 result.push_str(",");
704 result.push_str(&format!("{}{{{}}}", &sep, &sep));
706 result.push_str(" {}");
711 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
712 let width = offset.block_indent + context.config.tab_spaces() - 1;
713 let where_indent = Indent::new(0, width);
714 result.push_str(&where_indent.to_string_with_newline(context.config));
716 result.push_str(&where_clause_str);
718 let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n');
719 match context.config.brace_style() {
720 _ if need_newline => result.push_str(&sep),
721 BraceStyle::AlwaysNextLine => result.push_str(&sep),
722 BraceStyle::PreferSameLine => result.push(' '),
723 BraceStyle::SameLineWhere => {
724 if !where_clause_str.is_empty() {
725 result.push_str(&sep);
734 let snippet = context.snippet(item.span);
735 let open_pos = snippet.find_uncommented("{")? + 1;
737 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
738 let mut visitor = FmtVisitor::from_context(context);
739 let item_indent = offset.block_only().block_indent(context.config);
740 visitor.block_indent = item_indent;
741 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
743 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
744 visitor.visit_impl_items(items);
746 visitor.format_missing(item.span.hi() - BytePos(1));
748 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
749 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
751 result.push_str(&inner_indent_str);
752 result.push_str(visitor.buffer.to_string().trim());
753 result.push_str(&outer_indent_str);
756 if result.ends_with('{') {
757 result.push_str(&sep);
767 fn is_impl_single_line(
768 context: &RewriteContext,
769 items: &[ast::ImplItem],
771 where_clause_str: &str,
774 let snippet = context.snippet(item.span);
775 let open_pos = snippet.find_uncommented("{")? + 1;
778 context.config.empty_item_single_line()
780 && !result.contains('\n')
781 && result.len() + where_clause_str.len() <= context.config.max_width()
782 && !contains_comment(&snippet[open_pos..]),
786 fn format_impl_ref_and_type(
787 context: &RewriteContext,
790 ) -> Option<String> {
791 if let ast::ItemKind::Impl(
801 let mut result = String::with_capacity(128);
803 result.push_str(&format_visibility(&item.vis));
804 result.push_str(format_defaultness(defaultness));
805 result.push_str(format_unsafety(unsafety));
807 let lo = context.snippet_provider.span_after(item.span, "impl");
808 let hi = match *trait_ref {
809 Some(ref tr) => tr.path.span.lo(),
810 None => self_ty.span.lo(),
812 let shape = generics_shape_from_config(
814 Shape::indented(offset + last_line_width(&result), context.config),
817 let generics_str = rewrite_generics(context, "impl", generics, shape, mk_sp(lo, hi))?;
818 result.push_str(&generics_str);
820 let polarity_str = if polarity == ast::ImplPolarity::Negative {
826 if let Some(ref trait_ref) = *trait_ref {
827 let result_len = last_line_width(&result);
828 result.push_str(&rewrite_trait_ref(
837 // Try to put the self type in a single line.
839 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
840 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
841 // If there is no where clause adapt budget for type formatting to take space and curly
842 // brace into account.
843 match context.config.brace_style() {
844 BraceStyle::AlwaysNextLine => 0,
850 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
851 // 1 = space before the type.
852 let budget = context.budget(used_space + 1);
853 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
854 if !self_ty_str.contains('\n') {
855 if trait_ref.is_some() {
856 result.push_str(" for ");
860 result.push_str(&self_ty_str);
865 // Couldn't fit the self type on a single line, put it on a new line.
867 // Add indentation of one additional tab.
868 let new_line_offset = offset.block_indent(context.config);
869 result.push_str(&new_line_offset.to_string(context.config));
870 if trait_ref.is_some() {
871 result.push_str("for ");
873 let budget = context.budget(last_line_width(&result));
874 let type_offset = match context.config.indent_style() {
875 IndentStyle::Visual => new_line_offset + trait_ref_overhead,
876 IndentStyle::Block => new_line_offset,
878 result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?);
885 fn rewrite_trait_ref(
886 context: &RewriteContext,
887 trait_ref: &ast::TraitRef,
891 ) -> Option<String> {
892 // 1 = space between generics and trait_ref
893 let used_space = 1 + polarity_str.len() + result_len;
894 let shape = Shape::indented(offset + used_space, context.config);
895 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
896 if !trait_ref_str.contains('\n') {
897 return Some(format!(" {}{}", polarity_str, &trait_ref_str));
900 // We could not make enough space for trait_ref, so put it on new line.
901 let offset = offset.block_indent(context.config);
902 let shape = Shape::indented(offset, context.config);
903 let trait_ref_str = trait_ref.rewrite(context, shape)?;
906 &offset.to_string_with_newline(context.config),
912 pub struct StructParts<'a> {
915 vis: &'a ast::Visibility,
916 def: &'a ast::VariantData,
917 generics: Option<&'a ast::Generics>,
921 impl<'a> StructParts<'a> {
922 fn format_header(&self) -> String {
923 format_header(self.prefix, self.ident, self.vis)
926 fn from_variant(variant: &'a ast::Variant) -> Self {
929 ident: variant.node.ident,
930 vis: &DEFAULT_VISIBILITY,
931 def: &variant.node.data,
937 pub fn from_item(item: &'a ast::Item) -> Self {
938 let (prefix, def, generics) = match item.node {
939 ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics),
940 ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics),
948 generics: Some(generics),
955 context: &RewriteContext,
956 struct_parts: &StructParts,
958 one_line_width: Option<usize>,
959 ) -> Option<String> {
960 match *struct_parts.def {
961 ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
962 ast::VariantData::Tuple(ref fields, _) => {
963 format_tuple_struct(context, struct_parts, fields, offset)
965 ast::VariantData::Struct(ref fields, _) => {
966 format_struct_struct(context, struct_parts, fields, offset, one_line_width)
971 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
972 if let ast::ItemKind::Trait(
976 ref type_param_bounds,
980 let mut result = String::with_capacity(128);
981 let header = format!(
983 format_visibility(&item.vis),
984 format_unsafety(unsafety),
985 format_auto(is_auto),
987 result.push_str(&header);
989 let body_lo = context.snippet_provider.span_after(item.span, "{");
991 let shape = Shape::indented(offset, context.config).offset_left(result.len())?;
992 let generics_str = rewrite_generics(
994 &item.ident.to_string(),
997 mk_sp(item.span.lo(), body_lo),
999 result.push_str(&generics_str);
1001 // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds.
1002 if !type_param_bounds.is_empty() {
1003 let ident_hi = context
1005 .span_after(item.span, &format!("{}", item.ident));
1006 let bound_hi = type_param_bounds.last().unwrap().span().hi();
1007 let snippet = context.snippet(mk_sp(ident_hi, bound_hi));
1008 if contains_comment(snippet) {
1012 if !type_param_bounds.is_empty() {
1013 result = rewrite_assign_rhs_with(
1016 &TraitTyParamBounds::new(type_param_bounds),
1018 RhsTactics::ForceNextLine,
1022 // Rewrite where clause.
1023 if !generics.where_clause.predicates.is_empty() {
1024 let where_density = if context.config.indent_style() == IndentStyle::Block {
1030 let where_budget = context.budget(last_line_width(&result));
1031 let pos_before_where = if type_param_bounds.is_empty() {
1032 generics.where_clause.span.lo()
1034 type_param_bounds[type_param_bounds.len() - 1].span().hi()
1036 let option = WhereClauseOption::snuggled(&generics_str);
1037 let where_clause_str = rewrite_where_clause(
1039 &generics.where_clause,
1040 context.config.brace_style(),
1041 Shape::legacy(where_budget, offset.block_only()),
1049 // If the where clause cannot fit on the same line,
1050 // put the where clause on a new line
1051 if !where_clause_str.contains('\n')
1052 && last_line_width(&result) + where_clause_str.len() + offset.width()
1053 > context.config.comment_width()
1055 let width = offset.block_indent + context.config.tab_spaces() - 1;
1056 let where_indent = Indent::new(0, width);
1057 result.push_str(&where_indent.to_string_with_newline(context.config));
1059 result.push_str(&where_clause_str);
1061 let item_snippet = context.snippet(item.span);
1062 if let Some(lo) = item_snippet.find('/') {
1064 let comment_hi = body_lo - BytePos(1);
1065 let comment_lo = item.span.lo() + BytePos(lo as u32);
1066 if comment_lo < comment_hi {
1067 match recover_missing_comment_in_span(
1068 mk_sp(comment_lo, comment_hi),
1069 Shape::indented(offset, context.config),
1071 last_line_width(&result),
1073 Some(ref missing_comment) if !missing_comment.is_empty() => {
1074 result.push_str(missing_comment);
1082 match context.config.brace_style() {
1083 _ if last_line_contains_single_line_comment(&result)
1084 || last_line_width(&result) + 2 > context.budget(offset.width()) =>
1086 result.push_str(&offset.to_string_with_newline(context.config));
1088 BraceStyle::AlwaysNextLine => {
1089 result.push_str(&offset.to_string_with_newline(context.config));
1091 BraceStyle::PreferSameLine => result.push(' '),
1092 BraceStyle::SameLineWhere => {
1093 if result.contains('\n')
1094 || (!generics.where_clause.predicates.is_empty() && !trait_items.is_empty())
1096 result.push_str(&offset.to_string_with_newline(context.config));
1104 let snippet = context.snippet(item.span);
1105 let open_pos = snippet.find_uncommented("{")? + 1;
1107 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1108 let mut visitor = FmtVisitor::from_context(context);
1109 visitor.block_indent = offset.block_only().block_indent(context.config);
1110 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
1112 for item in trait_items {
1113 visitor.visit_trait_item(item);
1116 visitor.format_missing(item.span.hi() - BytePos(1));
1118 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
1119 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
1121 result.push_str(&inner_indent_str);
1122 result.push_str(visitor.buffer.to_string().trim());
1123 result.push_str(&outer_indent_str);
1124 } else if result.contains('\n') {
1135 pub fn format_trait_alias(
1136 context: &RewriteContext,
1138 generics: &ast::Generics,
1139 ty_param_bounds: &ast::TyParamBounds,
1141 ) -> Option<String> {
1142 let alias = ident.name.as_str();
1143 // 6 = "trait ", 2 = " ="
1144 let g_shape = shape.offset_left(6)?.sub_width(2)?;
1145 let generics_str = rewrite_generics(context, &alias, generics, g_shape, generics.span)?;
1146 let lhs = format!("trait {} =", generics_str);
1148 rewrite_assign_rhs(context, lhs, ty_param_bounds, shape.sub_width(1)?).map(|s| s + ";")
1151 fn format_unit_struct(context: &RewriteContext, p: &StructParts, offset: Indent) -> Option<String> {
1152 let header_str = format_header(p.prefix, p.ident, p.vis);
1153 let generics_str = if let Some(generics) = p.generics {
1154 let hi = if generics.where_clause.predicates.is_empty() {
1157 generics.where_clause.span.hi()
1162 context.config.brace_style(),
1165 mk_sp(generics.span.lo(), hi),
1166 last_line_width(&header_str),
1171 Some(format!("{}{};", header_str, generics_str))
1174 pub fn format_struct_struct(
1175 context: &RewriteContext,
1176 struct_parts: &StructParts,
1177 fields: &[ast::StructField],
1179 one_line_width: Option<usize>,
1180 ) -> Option<String> {
1181 let mut result = String::with_capacity(1024);
1182 let span = struct_parts.span;
1184 let header_str = struct_parts.format_header();
1185 result.push_str(&header_str);
1187 let header_hi = span.lo() + BytePos(header_str.len() as u32);
1188 let body_lo = context.snippet_provider.span_after(span, "{");
1190 let generics_str = match struct_parts.generics {
1191 Some(g) => format_generics(
1194 context.config.brace_style(),
1195 if fields.is_empty() {
1196 BracePos::ForceSameLine
1201 mk_sp(header_hi, body_lo),
1202 last_line_width(&result),
1205 // 3 = ` {}`, 2 = ` {`.
1206 let overhead = if fields.is_empty() { 3 } else { 2 };
1207 if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty())
1208 || context.config.max_width() < overhead + result.len()
1210 format!("\n{}{{", offset.block_only().to_string(context.config))
1217 let overhead = if fields.is_empty() { 1 } else { 0 };
1218 let total_width = result.len() + generics_str.len() + overhead;
1219 if !generics_str.is_empty()
1220 && !generics_str.contains('\n')
1221 && total_width > context.config.max_width()
1224 result.push_str(&offset.to_string(context.config));
1225 result.push_str(generics_str.trim_left());
1227 result.push_str(&generics_str);
1230 if fields.is_empty() {
1231 let inner_span = mk_sp(body_lo, span.hi() - BytePos(1));
1232 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "", "}");
1233 return Some(result);
1237 let one_line_budget = context.budget(result.len() + 3 + offset.width());
1238 let one_line_budget =
1239 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1241 let items_str = rewrite_with_alignment(
1244 Shape::indented(offset, context.config).sub_width(1)?,
1245 mk_sp(body_lo, span.hi()),
1249 if !items_str.contains('\n')
1250 && !result.contains('\n')
1251 && items_str.len() <= one_line_budget
1252 && !last_line_contains_single_line_comment(&items_str)
1254 Some(format!("{} {} }}", result, items_str))
1260 .block_indent(context.config)
1261 .to_string(context.config),
1263 offset.to_string(context.config)
1268 fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos {
1270 ast::VisibilityKind::Crate(..) | ast::VisibilityKind::Restricted { .. } => vis.span.hi(),
1271 _ => default_span.lo(),
1275 // Format tuple or struct without any fields. We need to make sure that the comments
1276 // inside the delimiters are preserved.
1277 fn format_empty_struct_or_tuple(
1278 context: &RewriteContext,
1281 result: &mut String,
1285 // 3 = " {}" or "();"
1286 let used_width = last_line_used_width(&result, offset.width()) + 3;
1287 if used_width > context.config.max_width() {
1288 result.push_str(&offset.to_string_with_newline(context.config))
1290 result.push_str(opener);
1291 match rewrite_missing_comment(span, Shape::indented(offset, context.config), context) {
1292 Some(ref s) if s.is_empty() => (),
1294 if !is_single_line(s) || first_line_contains_single_line_comment(s) {
1295 let nested_indent_str = offset
1296 .block_indent(context.config)
1297 .to_string_with_newline(context.config);
1298 result.push_str(&nested_indent_str);
1301 if last_line_contains_single_line_comment(s) {
1302 result.push_str(&offset.to_string_with_newline(context.config));
1305 None => result.push_str(context.snippet(span)),
1307 result.push_str(closer);
1310 fn format_tuple_struct(
1311 context: &RewriteContext,
1312 struct_parts: &StructParts,
1313 fields: &[ast::StructField],
1315 ) -> Option<String> {
1316 let mut result = String::with_capacity(1024);
1317 let span = struct_parts.span;
1319 let header_str = struct_parts.format_header();
1320 result.push_str(&header_str);
1322 let body_lo = if fields.is_empty() {
1323 let lo = get_bytepos_after_visibility(struct_parts.vis, span);
1326 .span_after(mk_sp(lo, span.hi()), "(")
1330 let body_hi = if fields.is_empty() {
1333 .span_after(mk_sp(body_lo, span.hi()), ")")
1335 // This is a dirty hack to work around a missing `)` from the span of the last field.
1336 let last_arg_span = fields[fields.len() - 1].span;
1337 if context.snippet(last_arg_span).ends_with(')') {
1342 .span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
1346 let where_clause_str = match struct_parts.generics {
1348 let budget = context.budget(last_line_width(&header_str));
1349 let shape = Shape::legacy(budget, offset);
1350 let g_span = mk_sp(span.lo(), body_lo);
1351 let generics_str = rewrite_generics(context, "", generics, shape, g_span)?;
1352 result.push_str(&generics_str);
1354 let where_budget = context.budget(last_line_width(&result));
1355 let option = WhereClauseOption::new(true, false);
1356 rewrite_where_clause(
1358 &generics.where_clause,
1359 context.config.brace_style(),
1360 Shape::legacy(where_budget, offset.block_only()),
1361 Density::Compressed,
1369 None => "".to_owned(),
1372 if fields.is_empty() {
1373 let body_hi = context
1375 .span_before(mk_sp(body_lo, span.hi()), ")");
1376 let inner_span = mk_sp(body_lo, body_hi);
1377 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "(", ")");
1379 let shape = Shape::indented(offset, context.config).sub_width(1)?;
1380 let fields = &fields.iter().collect::<Vec<_>>();
1381 result = overflow::rewrite_with_parens(
1387 context.config.width_heuristics().fn_call_width,
1392 if !where_clause_str.is_empty() && !where_clause_str.contains('\n')
1393 && (result.contains('\n')
1394 || offset.block_indent + result.len() + where_clause_str.len() + 1
1395 > context.config.max_width())
1397 // We need to put the where clause on a new line, but we didn't
1398 // know that earlier, so the where clause will not be indented properly.
1401 &(offset.block_only() + (context.config.tab_spaces() - 1)).to_string(context.config),
1404 result.push_str(&where_clause_str);
1409 pub fn rewrite_type_alias(
1410 context: &RewriteContext,
1414 generics: &ast::Generics,
1415 vis: &ast::Visibility,
1417 ) -> Option<String> {
1418 let mut result = String::with_capacity(128);
1420 result.push_str(&format_visibility(vis));
1421 result.push_str("type ");
1424 let g_shape = Shape::indented(indent, context.config)
1425 .offset_left(result.len())?
1428 context.snippet_provider.span_after(span, "type"),
1431 let generics_str = rewrite_generics(context, &ident.to_string(), generics, g_shape, g_span)?;
1432 result.push_str(&generics_str);
1434 let where_budget = context.budget(last_line_width(&result));
1435 let option = WhereClauseOption::snuggled(&result);
1436 let where_clause_str = rewrite_where_clause(
1438 &generics.where_clause,
1439 context.config.brace_style(),
1440 Shape::legacy(where_budget, indent),
1448 result.push_str(&where_clause_str);
1449 if where_clause_str.is_empty() {
1450 result.push_str(" =");
1452 result.push_str(&format!(
1454 indent.to_string_with_newline(context.config)
1459 let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
1460 rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
1463 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1465 if config.space_before_colon() { " " } else { "" },
1466 if config.space_after_colon() { " " } else { "" },
1470 pub fn rewrite_struct_field_prefix(
1471 context: &RewriteContext,
1472 field: &ast::StructField,
1473 ) -> Option<String> {
1474 let vis = format_visibility(&field.vis);
1475 let type_annotation_spacing = type_annotation_spacing(context.config);
1476 Some(match field.ident {
1477 Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
1478 None => format!("{}", vis),
1482 impl Rewrite for ast::StructField {
1483 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1484 rewrite_struct_field(context, self, shape, 0)
1488 pub fn rewrite_struct_field(
1489 context: &RewriteContext,
1490 field: &ast::StructField,
1492 lhs_max_width: usize,
1493 ) -> Option<String> {
1494 if contains_skip(&field.attrs) {
1495 return Some(context.snippet(field.span()).to_owned());
1498 let type_annotation_spacing = type_annotation_spacing(context.config);
1499 let prefix = rewrite_struct_field_prefix(context, field)?;
1501 let attrs_str = field.attrs.rewrite(context, shape)?;
1502 let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str);
1503 let missing_span = if field.attrs.is_empty() {
1504 mk_sp(field.span.lo(), field.span.lo())
1506 mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
1508 let mut spacing = String::from(if field.ident.is_some() {
1509 type_annotation_spacing.1
1513 // Try to put everything on a single line.
1514 let attr_prefix = combine_strs_with_missing_comments(
1522 let overhead = last_line_width(&attr_prefix);
1523 let lhs_offset = lhs_max_width.saturating_sub(overhead);
1524 for _ in 0..lhs_offset {
1527 // In this extreme case we will be missing a space betweeen an attribute and a field.
1528 if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
1532 .offset_left(overhead + spacing.len())
1533 .and_then(|ty_shape| field.ty.rewrite(context, ty_shape));
1534 if let Some(ref ty) = orig_ty {
1535 if !ty.contains('\n') {
1536 return Some(attr_prefix + &spacing + ty);
1540 let is_prefix_empty = prefix.is_empty();
1541 // We must use multiline. We are going to put attributes and a field on different lines.
1542 let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, shape)?;
1543 // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct.
1544 let field_str = if is_prefix_empty {
1545 field_str.trim_left()
1549 combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false)
1552 pub struct StaticParts<'a> {
1554 vis: &'a ast::Visibility,
1557 mutability: ast::Mutability,
1558 expr_opt: Option<&'a ptr::P<ast::Expr>>,
1559 defaultness: Option<ast::Defaultness>,
1563 impl<'a> StaticParts<'a> {
1564 pub fn from_item(item: &'a ast::Item) -> Self {
1565 let (prefix, ty, mutability, expr) = match item.node {
1566 ast::ItemKind::Static(ref ty, mutability, ref expr) => ("static", ty, mutability, expr),
1567 ast::ItemKind::Const(ref ty, ref expr) => {
1568 ("const", ty, ast::Mutability::Immutable, expr)
1570 _ => unreachable!(),
1578 expr_opt: Some(expr),
1584 pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
1585 let (ty, expr_opt) = match ti.node {
1586 ast::TraitItemKind::Const(ref ty, ref expr_opt) => (ty, expr_opt),
1587 _ => unreachable!(),
1591 vis: &DEFAULT_VISIBILITY,
1594 mutability: ast::Mutability::Immutable,
1595 expr_opt: expr_opt.as_ref(),
1601 pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
1602 let (ty, expr) = match ii.node {
1603 ast::ImplItemKind::Const(ref ty, ref expr) => (ty, expr),
1604 _ => unreachable!(),
1611 mutability: ast::Mutability::Immutable,
1612 expr_opt: Some(expr),
1613 defaultness: Some(ii.defaultness),
1620 context: &RewriteContext,
1621 static_parts: &StaticParts,
1623 ) -> Option<String> {
1624 let colon = colon_spaces(
1625 context.config.space_before_colon(),
1626 context.config.space_after_colon(),
1628 let mut prefix = format!(
1630 format_visibility(static_parts.vis),
1631 static_parts.defaultness.map_or("", format_defaultness),
1632 static_parts.prefix,
1633 format_mutability(static_parts.mutability),
1639 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?;
1640 let ty_str = match static_parts.ty.rewrite(context, ty_shape) {
1641 Some(ty_str) => ty_str,
1643 if prefix.ends_with(' ') {
1646 let nested_indent = offset.block_indent(context.config);
1647 let nested_shape = Shape::indented(nested_indent, context.config);
1648 let ty_str = static_parts.ty.rewrite(context, nested_shape)?;
1651 nested_indent.to_string_with_newline(context.config),
1657 if let Some(expr) = static_parts.expr_opt {
1658 let lhs = format!("{}{} =", prefix, ty_str);
1660 let remaining_width = context.budget(offset.block_indent + 1);
1665 Shape::legacy(remaining_width, offset.block_only()),
1666 ).and_then(|res| recover_comment_removed(res, static_parts.span, context))
1667 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1669 Some(format!("{}{};", prefix, ty_str))
1673 pub fn rewrite_associated_type(
1675 ty_opt: Option<&ptr::P<ast::Ty>>,
1676 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1677 context: &RewriteContext,
1679 ) -> Option<String> {
1680 let prefix = format!("type {}", ident);
1682 let type_bounds_str = if let Some(bounds) = ty_param_bounds_opt {
1683 if bounds.is_empty() {
1687 let shape = Shape::indented(indent, context.config).offset_left(prefix.len() + 2)?;
1688 bounds.rewrite(context, shape).map(|s| format!(": {}", s))?
1694 if let Some(ty) = ty_opt {
1696 let shape = Shape::indented(indent, context.config).sub_width(1)?;
1697 let lhs = format!("{}{} =", prefix, type_bounds_str);
1698 rewrite_assign_rhs(context, lhs, &**ty, shape).map(|s| s + ";")
1700 Some(format!("{}{};", prefix, type_bounds_str))
1704 pub fn rewrite_associated_impl_type(
1706 defaultness: ast::Defaultness,
1707 ty_opt: Option<&ptr::P<ast::Ty>>,
1708 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1709 context: &RewriteContext,
1711 ) -> Option<String> {
1712 let result = rewrite_associated_type(ident, ty_opt, ty_param_bounds_opt, context, indent)?;
1715 ast::Defaultness::Default => Some(format!("default {}", result)),
1720 impl Rewrite for ast::FunctionRetTy {
1721 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1723 ast::FunctionRetTy::Default(_) => Some(String::new()),
1724 ast::FunctionRetTy::Ty(ref ty) => {
1725 let inner_width = shape.width.checked_sub(3)?;
1726 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1727 .map(|r| format!("-> {}", r))
1733 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1735 ast::TyKind::Infer => {
1736 let original = context.snippet(ty.span);
1743 impl Rewrite for ast::Arg {
1744 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1745 if is_named_arg(self) {
1746 let mut result = self
1748 .rewrite(context, Shape::legacy(shape.width, shape.indent))?;
1750 if !is_empty_infer(context, &*self.ty) {
1751 if context.config.space_before_colon() {
1752 result.push_str(" ");
1754 result.push_str(":");
1755 if context.config.space_after_colon() {
1756 result.push_str(" ");
1758 let overhead = last_line_width(&result);
1759 let max_width = shape.width.checked_sub(overhead)?;
1762 .rewrite(context, Shape::legacy(max_width, shape.indent))?;
1763 result.push_str(&ty_str);
1768 self.ty.rewrite(context, shape)
1773 fn rewrite_explicit_self(
1774 explicit_self: &ast::ExplicitSelf,
1776 context: &RewriteContext,
1777 ) -> Option<String> {
1778 match explicit_self.node {
1779 ast::SelfKind::Region(lt, m) => {
1780 let mut_str = format_mutability(m);
1783 let lifetime_str = l.rewrite(
1785 Shape::legacy(context.config.max_width(), Indent::empty()),
1787 Some(format!("&{} {}self", lifetime_str, mut_str))
1789 None => Some(format!("&{}self", mut_str)),
1792 ast::SelfKind::Explicit(ref ty, _) => {
1793 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1795 let mutability = explicit_self_mutability(&args[0]);
1796 let type_str = ty.rewrite(
1798 Shape::legacy(context.config.max_width(), Indent::empty()),
1803 format_mutability(mutability),
1807 ast::SelfKind::Value(_) => {
1808 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1810 let mutability = explicit_self_mutability(&args[0]);
1812 Some(format!("{}self", format_mutability(mutability)))
1817 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1818 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1819 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1820 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1827 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1828 if is_named_arg(arg) {
1835 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1837 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
1838 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
1839 _ => arg.ty.span.hi(),
1843 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1844 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1845 ident != symbol::keywords::Invalid.ident()
1851 // Return type is (result, force_new_line_for_brace)
1853 context: &RewriteContext,
1858 newline_brace: bool,
1860 ) -> Option<(String, bool)> {
1861 let mut force_new_line_for_brace = false;
1863 let where_clause = &fn_sig.generics.where_clause;
1865 let mut result = String::with_capacity(1024);
1866 result.push_str(&fn_sig.to_str(context));
1869 result.push_str("fn ");
1872 let overhead = if has_body && !newline_brace {
1879 let used_width = last_line_used_width(&result, indent.width());
1880 let one_line_budget = context.budget(used_width + overhead);
1882 width: one_line_budget,
1886 let fd = fn_sig.decl;
1887 let g_span = mk_sp(span.lo(), fd.output.span().lo());
1889 rewrite_generics(context, &ident.to_string(), fn_sig.generics, shape, g_span)?;
1890 result.push_str(&generics_str);
1892 let snuggle_angle_bracket = generics_str
1895 .map_or(false, |l| l.trim_left().len() == 1);
1897 // Note that the width and indent don't really matter, we'll re-layout the
1898 // return type later anyway.
1901 .rewrite(context, Shape::indented(indent, context.config))?;
1903 let multi_line_ret_str = ret_str.contains('\n');
1904 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1907 let (one_line_budget, multi_line_budget, mut arg_indent) = compute_budgets_for_args(
1918 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1919 one_line_budget, multi_line_budget, arg_indent
1922 // Check if vertical layout was forced.
1923 if one_line_budget == 0 {
1924 if snuggle_angle_bracket {
1927 result.push_str("(");
1928 if context.config.indent_style() == IndentStyle::Visual {
1929 result.push_str(&arg_indent.to_string_with_newline(context.config));
1936 // Skip `pub(crate)`.
1937 let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
1938 // A conservative estimation, to goal is to be over all parens in generics
1939 let args_start = fn_sig
1944 .map_or(lo_after_visibility, |param| param.span().hi());
1945 let args_end = if fd.inputs.is_empty() {
1948 .span_after(mk_sp(args_start, span.hi()), ")")
1950 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
1951 context.snippet_provider.span_after(last_span, ")")
1953 let args_span = mk_sp(
1956 .span_after(mk_sp(args_start, span.hi()), "("),
1959 let arg_str = rewrite_args(
1962 fd.get_self().as_ref(),
1969 generics_str.contains('\n'),
1972 let put_args_in_block = match context.config.indent_style() {
1973 IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
1975 } && !fd.inputs.is_empty();
1977 let mut args_last_line_contains_comment = false;
1978 if put_args_in_block {
1979 arg_indent = indent.block_indent(context.config);
1980 result.push_str(&arg_indent.to_string_with_newline(context.config));
1981 result.push_str(&arg_str);
1982 result.push_str(&indent.to_string_with_newline(context.config));
1985 result.push_str(&arg_str);
1986 let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
1987 // Put the closing brace on the next line if it overflows the max width.
1989 if fd.inputs.is_empty() && used_width + 1 > context.config.max_width() {
1992 // If the last line of args contains comment, we cannot put the closing paren
1993 // on the same line.
1997 .map_or(false, |last_line| last_line.contains("//"))
1999 args_last_line_contains_comment = true;
2000 result.push_str(&arg_indent.to_string_with_newline(context.config));
2006 if let ast::FunctionRetTy::Ty(..) = fd.output {
2007 let ret_should_indent = match context.config.indent_style() {
2008 // If our args are block layout then we surely must have space.
2009 IndentStyle::Block if put_args_in_block || fd.inputs.is_empty() => false,
2010 _ if args_last_line_contains_comment => false,
2011 _ if result.contains('\n') || multi_line_ret_str => true,
2013 // If the return type would push over the max width, then put the return type on
2014 // a new line. With the +1 for the signature length an additional space between
2015 // the closing parenthesis of the argument and the arrow '->' is considered.
2016 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
2018 // If there is no where clause, take into account the space after the return type
2020 if where_clause.predicates.is_empty() {
2024 sig_length > context.config.max_width()
2027 let ret_indent = if ret_should_indent {
2028 let indent = if arg_str.is_empty() {
2029 // Aligning with non-existent args looks silly.
2030 force_new_line_for_brace = true;
2033 // FIXME: we might want to check that using the arg indent
2034 // doesn't blow our budget, and if it does, then fallback to
2035 // the where clause indent.
2039 result.push_str(&indent.to_string_with_newline(context.config));
2043 Indent::new(indent.block_indent, last_line_width(&result))
2046 if multi_line_ret_str || ret_should_indent {
2047 // Now that we know the proper indent and width, we need to
2048 // re-layout the return type.
2051 .rewrite(context, Shape::indented(ret_indent, context.config))?;
2052 result.push_str(&ret_str);
2054 result.push_str(&ret_str);
2057 // Comment between return type and the end of the decl.
2058 let snippet_lo = fd.output.span().hi();
2059 if where_clause.predicates.is_empty() {
2060 let snippet_hi = span.hi();
2061 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2062 // Try to preserve the layout of the original snippet.
2063 let original_starts_with_newline = snippet
2065 .map_or(false, |i| starts_with_newline(&snippet[i..]));
2066 let original_ends_with_newline = snippet
2067 .rfind(|c| c != ' ')
2068 .map_or(false, |i| snippet[i..].ends_with('\n'));
2069 let snippet = snippet.trim();
2070 if !snippet.is_empty() {
2071 result.push(if original_starts_with_newline {
2076 result.push_str(snippet);
2077 if original_ends_with_newline {
2078 force_new_line_for_brace = true;
2084 let pos_before_where = match fd.output {
2085 ast::FunctionRetTy::Default(..) => args_span.hi(),
2086 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
2089 let is_args_multi_lined = arg_str.contains('\n');
2091 let option = WhereClauseOption::new(!has_body, put_args_in_block && ret_str.is_empty());
2092 let where_clause_str = rewrite_where_clause(
2095 context.config.brace_style(),
2096 Shape::indented(indent, context.config),
2102 is_args_multi_lined,
2104 // If there are neither where clause nor return type, we may be missing comments between
2106 if where_clause_str.is_empty() {
2107 if let ast::FunctionRetTy::Default(ret_span) = fd.output {
2108 match recover_missing_comment_in_span(
2109 mk_sp(args_span.hi(), ret_span.hi()),
2112 last_line_width(&result),
2114 Some(ref missing_comment) if !missing_comment.is_empty() => {
2115 result.push_str(missing_comment);
2116 force_new_line_for_brace = true;
2123 result.push_str(&where_clause_str);
2125 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2126 force_new_line_for_brace |= is_args_multi_lined && context.config.where_single_line();
2127 Some((result, force_new_line_for_brace))
2130 #[derive(Copy, Clone)]
2131 struct WhereClauseOption {
2132 suppress_comma: bool, // Force no trailing comma
2133 snuggle: bool, // Do not insert newline before `where`
2134 compress_where: bool, // Try single line where clause instead of vertical layout
2137 impl WhereClauseOption {
2138 pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
2142 compress_where: false,
2146 pub fn snuggled(current: &str) -> WhereClauseOption {
2148 suppress_comma: false,
2149 snuggle: trimmed_last_line_width(current) == 1,
2150 compress_where: false,
2154 pub fn suppress_comma(&mut self) {
2155 self.suppress_comma = true
2158 pub fn compress_where(&mut self) {
2159 self.compress_where = true
2162 pub fn snuggle(&mut self) {
2168 context: &RewriteContext,
2170 explicit_self: Option<&ast::ExplicitSelf>,
2171 one_line_budget: usize,
2172 multi_line_budget: usize,
2177 generics_str_contains_newline: bool,
2178 ) -> Option<String> {
2179 let mut arg_item_strs = args
2181 .map(|arg| arg.rewrite(context, Shape::legacy(multi_line_budget, arg_indent)))
2182 .collect::<Option<Vec<_>>>()?;
2184 // Account for sugary self.
2185 // FIXME: the comment for the self argument is dropped. This is blocked
2186 // on rust issue #27522.
2187 let min_args = explicit_self
2188 .and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
2189 .map_or(1, |self_str| {
2190 arg_item_strs[0] = self_str;
2194 // Comments between args.
2195 let mut arg_items = Vec::new();
2197 arg_items.push(ListItem::from_str(""));
2200 // FIXME(#21): if there are no args, there might still be a comment, but
2201 // without spans for the comment or parens, there is no chance of
2202 // getting it right. You also don't get to put a comment on self, unless
2204 if args.len() >= min_args || variadic {
2205 let comment_span_start = if min_args == 2 {
2206 let second_arg_start = if arg_has_pattern(&args[1]) {
2207 args[1].pat.span.lo()
2209 args[1].ty.span.lo()
2211 let reduced_span = mk_sp(span.lo(), second_arg_start);
2213 context.snippet_provider.span_after_last(reduced_span, ",")
2218 enum ArgumentKind<'a> {
2219 Regular(&'a ast::Arg),
2223 let variadic_arg = if variadic {
2224 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
2225 let variadic_start =
2226 context.snippet_provider.span_after(variadic_span, "...") - BytePos(3);
2227 Some(ArgumentKind::Variadic(variadic_start))
2232 let more_items = itemize_list(
2233 context.snippet_provider,
2234 args[min_args - 1..]
2236 .map(ArgumentKind::Regular)
2237 .chain(variadic_arg),
2241 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2242 ArgumentKind::Variadic(start) => start,
2245 ArgumentKind::Regular(arg) => arg.ty.span.hi(),
2246 ArgumentKind::Variadic(start) => start + BytePos(3),
2249 ArgumentKind::Regular(..) => None,
2250 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2257 arg_items.extend(more_items);
2260 let fits_in_one_line = !generics_str_contains_newline
2261 && (arg_items.is_empty()
2262 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2264 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2265 item.item = Some(arg);
2268 let last_line_ends_with_comment = arg_items
2271 .and_then(|item| item.post_comment.as_ref())
2272 .map_or(false, |s| s.trim().starts_with("//"));
2274 let (indent, trailing_comma) = match context.config.indent_style() {
2275 IndentStyle::Block if fits_in_one_line => {
2276 (indent.block_indent(context.config), SeparatorTactic::Never)
2278 IndentStyle::Block => (
2279 indent.block_indent(context.config),
2280 context.config.trailing_comma(),
2282 IndentStyle::Visual if last_line_ends_with_comment => {
2283 (arg_indent, context.config.trailing_comma())
2285 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2288 let tactic = definitive_tactic(
2290 context.config.fn_args_density().to_list_tactic(),
2294 let budget = match tactic {
2295 DefinitiveListTactic::Horizontal => one_line_budget,
2296 _ => multi_line_budget,
2299 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2301 let fmt = ListFormatting {
2304 trailing_separator: if variadic {
2305 SeparatorTactic::Never
2309 separator_place: SeparatorPlace::Back,
2310 shape: Shape::legacy(budget, indent),
2311 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2312 preserve_newline: true,
2313 config: context.config,
2316 write_list(&arg_items, &fmt)
2319 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2320 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2321 ident != symbol::keywords::Invalid.ident()
2327 fn compute_budgets_for_args(
2328 context: &RewriteContext,
2332 newline_brace: bool,
2334 force_vertical_layout: bool,
2335 ) -> Option<((usize, usize, Indent))> {
2337 "compute_budgets_for_args {} {:?}, {}, {}",
2343 // Try keeping everything on the same line.
2344 if !result.contains('\n') && !force_vertical_layout {
2345 // 2 = `()`, 3 = `() `, space is before ret_string.
2346 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2347 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2357 let one_line_budget = context.budget(used_space);
2359 if one_line_budget > 0 {
2361 let (indent, multi_line_budget) = match context.config.indent_style() {
2362 IndentStyle::Block => {
2363 let indent = indent.block_indent(context.config);
2364 (indent, context.budget(indent.width() + 1))
2366 IndentStyle::Visual => {
2367 let indent = indent + result.len() + 1;
2368 let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
2369 (indent, context.budget(multi_line_overhead))
2373 return Some((one_line_budget, multi_line_budget, indent));
2377 // Didn't work. we must force vertical layout and put args on a newline.
2378 let new_indent = indent.block_indent(context.config);
2379 let used_space = match context.config.indent_style() {
2381 IndentStyle::Block => new_indent.width() + 1,
2382 // Account for `)` and possibly ` {`.
2383 IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
2385 Some((0, context.budget(used_space), new_indent))
2388 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2389 let predicate_count = where_clause.predicates.len();
2391 if config.where_single_line() && predicate_count == 1 {
2394 let brace_style = config.brace_style();
2396 brace_style == BraceStyle::AlwaysNextLine
2397 || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0)
2400 fn rewrite_generics(
2401 context: &RewriteContext,
2403 generics: &ast::Generics,
2406 ) -> Option<String> {
2407 // FIXME: convert bounds to where clauses where they get too big or if
2408 // there is a where clause at all.
2410 if generics.params.is_empty() {
2411 return Some(ident.to_owned());
2414 let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>();
2415 overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
2418 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2419 match config.indent_style() {
2420 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2421 IndentStyle::Block => {
2425 .block_indent(config.tab_spaces())
2426 .with_max_width(config)
2432 fn rewrite_where_clause_rfc_style(
2433 context: &RewriteContext,
2434 where_clause: &ast::WhereClause,
2437 span_end: Option<BytePos>,
2438 span_end_before_where: BytePos,
2439 where_clause_option: WhereClauseOption,
2440 is_args_multi_line: bool,
2441 ) -> Option<String> {
2442 let block_shape = shape.block().with_max_width(context.config);
2444 let (span_before, span_after) =
2445 missing_span_before_after_where(span_end_before_where, where_clause);
2446 let (comment_before, comment_after) =
2447 rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
2449 let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
2452 block_shape.indent.to_string_with_newline(context.config)
2455 let clause_shape = block_shape.block_left(context.config.tab_spaces())?;
2457 let clause_shape = clause_shape.sub_width(1)?;
2458 // each clause on one line, trailing comma (except if suppress_comma)
2459 let span_start = where_clause.predicates[0].span().lo();
2460 // If we don't have the start of the next span, then use the end of the
2461 // predicates, but that means we miss comments.
2462 let len = where_clause.predicates.len();
2463 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2464 let span_end = span_end.unwrap_or(end_of_preds);
2465 let items = itemize_list(
2466 context.snippet_provider,
2467 where_clause.predicates.iter(),
2470 |pred| pred.span().lo(),
2471 |pred| pred.span().hi(),
2472 |pred| pred.rewrite(context, clause_shape),
2477 let where_single_line = context.config.where_single_line() && len == 1 && !is_args_multi_line;
2478 let comma_tactic = if where_clause_option.suppress_comma || where_single_line {
2479 SeparatorTactic::Never
2481 context.config.trailing_comma()
2484 // shape should be vertical only and only if we have `where_single_line` option enabled
2485 // and the number of items of the where clause is equal to 1
2486 let shape_tactic = if where_single_line {
2487 DefinitiveListTactic::Horizontal
2489 DefinitiveListTactic::Vertical
2492 let fmt = ListFormatting {
2493 tactic: shape_tactic,
2495 trailing_separator: comma_tactic,
2496 separator_place: SeparatorPlace::Back,
2497 shape: clause_shape,
2498 ends_with_newline: true,
2499 preserve_newline: true,
2500 config: context.config,
2502 let preds_str = write_list(&items.collect::<Vec<_>>(), &fmt)?;
2504 let comment_separator = |comment: &str, shape: Shape| {
2505 if comment.is_empty() {
2508 shape.indent.to_string_with_newline(context.config)
2511 let newline_before_where = comment_separator(&comment_before, shape);
2512 let newline_after_where = comment_separator(&comment_after, clause_shape);
2515 let clause_sep = if where_clause_option.compress_where
2516 && comment_before.is_empty()
2517 && comment_after.is_empty()
2518 && !preds_str.contains('\n')
2519 && 6 + preds_str.len() <= shape.width || where_single_line
2523 clause_shape.indent.to_string_with_newline(context.config)
2526 "{}{}{}where{}{}{}{}",
2529 newline_before_where,
2530 newline_after_where,
2537 fn rewrite_where_clause(
2538 context: &RewriteContext,
2539 where_clause: &ast::WhereClause,
2540 brace_style: BraceStyle,
2544 span_end: Option<BytePos>,
2545 span_end_before_where: BytePos,
2546 where_clause_option: WhereClauseOption,
2547 is_args_multi_line: bool,
2548 ) -> Option<String> {
2549 if where_clause.predicates.is_empty() {
2550 return Some(String::new());
2553 if context.config.indent_style() == IndentStyle::Block {
2554 return rewrite_where_clause_rfc_style(
2560 span_end_before_where,
2561 where_clause_option,
2566 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2568 let offset = match context.config.indent_style() {
2569 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2570 // 6 = "where ".len()
2571 IndentStyle::Visual => shape.indent + extra_indent + 6,
2573 // FIXME: if indent_style != Visual, then the budgets below might
2574 // be out by a char or two.
2576 let budget = context.config.max_width() - offset.width();
2577 let span_start = where_clause.predicates[0].span().lo();
2578 // If we don't have the start of the next span, then use the end of the
2579 // predicates, but that means we miss comments.
2580 let len = where_clause.predicates.len();
2581 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2582 let span_end = span_end.unwrap_or(end_of_preds);
2583 let items = itemize_list(
2584 context.snippet_provider,
2585 where_clause.predicates.iter(),
2588 |pred| pred.span().lo(),
2589 |pred| pred.span().hi(),
2590 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2595 let item_vec = items.collect::<Vec<_>>();
2596 // FIXME: we don't need to collect here
2597 let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget);
2599 let mut comma_tactic = context.config.trailing_comma();
2600 // Kind of a hack because we don't usually have trailing commas in where clauses.
2601 if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
2602 comma_tactic = SeparatorTactic::Never;
2605 let fmt = ListFormatting {
2608 trailing_separator: comma_tactic,
2609 separator_place: SeparatorPlace::Back,
2610 shape: Shape::legacy(budget, offset),
2611 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2612 preserve_newline: true,
2613 config: context.config,
2615 let preds_str = write_list(&item_vec, &fmt)?;
2617 let end_length = if terminator == "{" {
2618 // If the brace is on the next line we don't need to count it otherwise it needs two
2621 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2622 BraceStyle::PreferSameLine => 2,
2624 } else if terminator == "=" {
2629 if density == Density::Tall
2630 || preds_str.contains('\n')
2631 || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2635 (shape.indent + extra_indent).to_string(context.config),
2639 Some(format!(" where {}", preds_str))
2643 fn missing_span_before_after_where(
2644 before_item_span_end: BytePos,
2645 where_clause: &ast::WhereClause,
2647 let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
2649 let pos_after_where = where_clause.span.lo() + BytePos(5);
2650 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
2651 (missing_span_before, missing_span_after)
2654 fn rewrite_comments_before_after_where(
2655 context: &RewriteContext,
2656 span_before_where: Span,
2657 span_after_where: Span,
2659 ) -> Option<(String, String)> {
2660 let before_comment = rewrite_missing_comment(span_before_where, shape, context)?;
2661 let after_comment = rewrite_missing_comment(
2663 shape.block_indent(context.config.tab_spaces()),
2666 Some((before_comment, after_comment))
2669 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2670 format!("{}{}{}", format_visibility(vis), item_name, ident)
2673 #[derive(PartialEq, Eq, Clone, Copy)]
2681 context: &RewriteContext,
2682 generics: &ast::Generics,
2683 brace_style: BraceStyle,
2684 brace_pos: BracePos,
2688 ) -> Option<String> {
2689 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2690 let mut result = rewrite_generics(context, "", generics, shape, span)?;
2692 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2693 let budget = context.budget(last_line_used_width(&result, offset.width()));
2694 let mut option = WhereClauseOption::snuggled(&result);
2695 if brace_pos == BracePos::None {
2696 option.suppress_comma = true;
2698 // If the generics are not parameterized then generics.span.hi() == 0,
2699 // so we use span.lo(), which is the position after `struct Foo`.
2700 let span_end_before_where = if generics.is_parameterized() {
2705 let where_clause_str = rewrite_where_clause(
2707 &generics.where_clause,
2709 Shape::legacy(budget, offset.block_only()),
2713 span_end_before_where,
2717 result.push_str(&where_clause_str);
2718 brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine
2719 || (generics.where_clause.predicates.is_empty()
2720 && trimmed_last_line_width(&result) == 1)
2722 brace_pos == BracePos::ForceSameLine
2723 || trimmed_last_line_width(&result) == 1
2724 || brace_style != BraceStyle::AlwaysNextLine
2726 if brace_pos == BracePos::None {
2727 return Some(result);
2729 let total_used_width = last_line_used_width(&result, used_width);
2730 let remaining_budget = context.budget(total_used_width);
2731 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2732 // and hence we take the closer into account as well for one line budget.
2733 // We assume that the closer has the same length as the opener.
2734 let overhead = if brace_pos == BracePos::ForceSameLine {
2741 let forbid_same_line_brace = overhead > remaining_budget;
2742 if !forbid_same_line_brace && same_line_brace {
2746 result.push_str(&offset.block_only().to_string(context.config));
2753 impl Rewrite for ast::ForeignItem {
2754 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2755 let attrs_str = self.attrs.rewrite(context, shape)?;
2756 // Drop semicolon or it will be interpreted as comment.
2757 // FIXME: this may be a faulty span from libsyntax.
2758 let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
2760 let item_str = match self.node {
2761 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
2766 &FnSig::new(fn_decl, generics, self.vis.clone()),
2770 ).map(|(s, _)| format!("{};", s))
2772 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
2773 // FIXME(#21): we're dropping potential comments in between the
2774 // function keywords here.
2775 let vis = format_visibility(&self.vis);
2776 let mut_str = if is_mutable { "mut " } else { "" };
2777 let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
2779 rewrite_assign_rhs(context, prefix, &**ty, shape.sub_width(1)?).map(|s| s + ";")
2781 ast::ForeignItemKind::Ty => {
2782 let vis = format_visibility(&self.vis);
2783 Some(format!("{}type {};", vis, self.ident))
2785 ast::ForeignItemKind::Macro(ref mac) => {
2786 rewrite_macro(mac, None, context, shape, MacroPosition::Item)
2790 let missing_span = if self.attrs.is_empty() {
2791 mk_sp(self.span.lo(), self.span.lo())
2793 mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
2795 combine_strs_with_missing_comments(
2806 impl Rewrite for ast::GenericParam {
2807 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2809 ast::GenericParam::Lifetime(ref lifetime_def) => lifetime_def.rewrite(context, shape),
2810 ast::GenericParam::Type(ref ty) => ty.rewrite(context, shape),
2815 /// Rewrite an inline mod.
2816 pub fn rewrite_mod(item: &ast::Item) -> String {
2817 let mut result = String::with_capacity(32);
2818 result.push_str(&*format_visibility(&item.vis));
2819 result.push_str("mod ");
2820 result.push_str(&item.ident.to_string());
2825 /// Rewrite `extern crate foo;` WITHOUT attributes.
2826 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
2827 assert!(is_extern_crate(item));
2828 let new_str = context.snippet(item.span);
2829 Some(if contains_comment(new_str) {
2832 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
2833 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
2837 /// Returns true for `mod foo;`, false for `mod foo { .. }`.
2838 pub fn is_mod_decl(item: &ast::Item) -> bool {
2840 ast::ItemKind::Mod(ref m) => m.inner.hi() != item.span.hi(),
2845 pub fn is_use_item(item: &ast::Item) -> bool {
2847 ast::ItemKind::Use(_) => true,
2852 pub fn is_extern_crate(item: &ast::Item) -> bool {
2854 ast::ItemKind::ExternCrate(..) => true,