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
659 && !result.contains('\n')
661 option.suppress_comma();
663 option.compress_where();
666 let mut where_clause_str = rewrite_where_clause(
668 &generics.where_clause,
669 context.config.brace_style(),
670 Shape::legacy(where_budget, offset.block_only()),
679 // If there is no where clause, we may have missing comments between the trait name and
680 // the opening brace.
681 if generics.where_clause.predicates.is_empty() {
682 if let Some(hi) = where_span_end {
683 match recover_missing_comment_in_span(
684 mk_sp(self_ty.span.hi(), hi),
685 Shape::indented(offset, context.config),
687 last_line_width(&result),
689 Some(ref missing_comment) if !missing_comment.is_empty() => {
690 result.push_str(missing_comment);
697 if is_impl_single_line(context, items, &result, &where_clause_str, item)? {
698 result.push_str(&where_clause_str);
699 if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) {
700 // if the where_clause contains extra comments AND
701 // there is only one where clause predicate
702 // recover the suppressed comma in single line where_clause formatting
703 if generics.where_clause.predicates.len() == 1 {
704 result.push_str(",");
706 result.push_str(&format!("{}{{{}}}", &sep, &sep));
708 result.push_str(" {}");
713 result.push_str(&where_clause_str);
715 let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n');
716 match context.config.brace_style() {
717 _ if need_newline => result.push_str(&sep),
718 BraceStyle::AlwaysNextLine => result.push_str(&sep),
719 BraceStyle::PreferSameLine => result.push(' '),
720 BraceStyle::SameLineWhere => {
721 if !where_clause_str.is_empty() {
722 result.push_str(&sep);
731 let snippet = context.snippet(item.span);
732 let open_pos = snippet.find_uncommented("{")? + 1;
734 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
735 let mut visitor = FmtVisitor::from_context(context);
736 let item_indent = offset.block_only().block_indent(context.config);
737 visitor.block_indent = item_indent;
738 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
740 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
741 visitor.visit_impl_items(items);
743 visitor.format_missing(item.span.hi() - BytePos(1));
745 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
746 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
748 result.push_str(&inner_indent_str);
749 result.push_str(visitor.buffer.to_string().trim());
750 result.push_str(&outer_indent_str);
753 if result.ends_with('{') && !context.config.empty_item_single_line() {
754 result.push_str(&sep);
764 fn is_impl_single_line(
765 context: &RewriteContext,
766 items: &[ast::ImplItem],
768 where_clause_str: &str,
771 let snippet = context.snippet(item.span);
772 let open_pos = snippet.find_uncommented("{")? + 1;
775 context.config.empty_item_single_line()
777 && !result.contains('\n')
778 && result.len() + where_clause_str.len() <= context.config.max_width()
779 && !contains_comment(&snippet[open_pos..]),
783 fn format_impl_ref_and_type(
784 context: &RewriteContext,
787 ) -> Option<String> {
788 if let ast::ItemKind::Impl(
798 let mut result = String::with_capacity(128);
800 result.push_str(&format_visibility(&item.vis));
801 result.push_str(format_defaultness(defaultness));
802 result.push_str(format_unsafety(unsafety));
804 let lo = context.snippet_provider.span_after(item.span, "impl");
805 let hi = match *trait_ref {
806 Some(ref tr) => tr.path.span.lo(),
807 None => self_ty.span.lo(),
809 let shape = generics_shape_from_config(
811 Shape::indented(offset + last_line_width(&result), context.config),
814 let generics_str = rewrite_generics(context, "impl", generics, shape, mk_sp(lo, hi))?;
815 result.push_str(&generics_str);
817 let polarity_str = if polarity == ast::ImplPolarity::Negative {
823 if let Some(ref trait_ref) = *trait_ref {
824 let result_len = last_line_width(&result);
825 result.push_str(&rewrite_trait_ref(
834 // Try to put the self type in a single line.
836 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
837 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
838 // If there is no where clause adapt budget for type formatting to take space and curly
839 // brace into account.
840 match context.config.brace_style() {
841 BraceStyle::AlwaysNextLine => 0,
847 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
848 // 1 = space before the type.
849 let budget = context.budget(used_space + 1);
850 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
851 if !self_ty_str.contains('\n') {
852 if trait_ref.is_some() {
853 result.push_str(" for ");
857 result.push_str(&self_ty_str);
862 // Couldn't fit the self type on a single line, put it on a new line.
864 // Add indentation of one additional tab.
865 let new_line_offset = offset.block_indent(context.config);
866 result.push_str(&new_line_offset.to_string(context.config));
867 if trait_ref.is_some() {
868 result.push_str("for ");
870 let budget = context.budget(last_line_width(&result));
871 let type_offset = match context.config.indent_style() {
872 IndentStyle::Visual => new_line_offset + trait_ref_overhead,
873 IndentStyle::Block => new_line_offset,
875 result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?);
882 fn rewrite_trait_ref(
883 context: &RewriteContext,
884 trait_ref: &ast::TraitRef,
888 ) -> Option<String> {
889 // 1 = space between generics and trait_ref
890 let used_space = 1 + polarity_str.len() + result_len;
891 let shape = Shape::indented(offset + used_space, context.config);
892 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
893 if !trait_ref_str.contains('\n') {
894 return Some(format!(" {}{}", polarity_str, &trait_ref_str));
897 // We could not make enough space for trait_ref, so put it on new line.
898 let offset = offset.block_indent(context.config);
899 let shape = Shape::indented(offset, context.config);
900 let trait_ref_str = trait_ref.rewrite(context, shape)?;
903 &offset.to_string_with_newline(context.config),
909 pub struct StructParts<'a> {
912 vis: &'a ast::Visibility,
913 def: &'a ast::VariantData,
914 generics: Option<&'a ast::Generics>,
918 impl<'a> StructParts<'a> {
919 fn format_header(&self) -> String {
920 format_header(self.prefix, self.ident, self.vis)
923 fn from_variant(variant: &'a ast::Variant) -> Self {
926 ident: variant.node.ident,
927 vis: &DEFAULT_VISIBILITY,
928 def: &variant.node.data,
934 pub fn from_item(item: &'a ast::Item) -> Self {
935 let (prefix, def, generics) = match item.node {
936 ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics),
937 ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics),
945 generics: Some(generics),
952 context: &RewriteContext,
953 struct_parts: &StructParts,
955 one_line_width: Option<usize>,
956 ) -> Option<String> {
957 match *struct_parts.def {
958 ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
959 ast::VariantData::Tuple(ref fields, _) => {
960 format_tuple_struct(context, struct_parts, fields, offset)
962 ast::VariantData::Struct(ref fields, _) => {
963 format_struct_struct(context, struct_parts, fields, offset, one_line_width)
968 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
969 if let ast::ItemKind::Trait(
973 ref type_param_bounds,
977 let mut result = String::with_capacity(128);
978 let header = format!(
980 format_visibility(&item.vis),
981 format_unsafety(unsafety),
982 format_auto(is_auto),
984 result.push_str(&header);
986 let body_lo = context.snippet_provider.span_after(item.span, "{");
988 let shape = Shape::indented(offset, context.config).offset_left(result.len())?;
989 let generics_str = rewrite_generics(
991 &item.ident.to_string(),
994 mk_sp(item.span.lo(), body_lo),
996 result.push_str(&generics_str);
998 // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds.
999 if !type_param_bounds.is_empty() {
1000 let ident_hi = context
1002 .span_after(item.span, &format!("{}", item.ident));
1003 let bound_hi = type_param_bounds.last().unwrap().span().hi();
1004 let snippet = context.snippet(mk_sp(ident_hi, bound_hi));
1005 if contains_comment(snippet) {
1009 if !type_param_bounds.is_empty() {
1010 result = rewrite_assign_rhs_with(
1013 &TraitTyParamBounds::new(type_param_bounds),
1015 RhsTactics::ForceNextLine,
1019 // Rewrite where clause.
1020 if !generics.where_clause.predicates.is_empty() {
1021 let where_density = if context.config.indent_style() == IndentStyle::Block {
1027 let where_budget = context.budget(last_line_width(&result));
1028 let pos_before_where = if type_param_bounds.is_empty() {
1029 generics.where_clause.span.lo()
1031 type_param_bounds[type_param_bounds.len() - 1].span().hi()
1033 let option = WhereClauseOption::snuggled(&generics_str);
1034 let where_clause_str = rewrite_where_clause(
1036 &generics.where_clause,
1037 context.config.brace_style(),
1038 Shape::legacy(where_budget, offset.block_only()),
1046 // If the where clause cannot fit on the same line,
1047 // put the where clause on a new line
1048 if !where_clause_str.contains('\n')
1049 && last_line_width(&result) + where_clause_str.len() + offset.width()
1050 > context.config.comment_width()
1052 let width = offset.block_indent + context.config.tab_spaces() - 1;
1053 let where_indent = Indent::new(0, width);
1054 result.push_str(&where_indent.to_string_with_newline(context.config));
1056 result.push_str(&where_clause_str);
1058 let item_snippet = context.snippet(item.span);
1059 if let Some(lo) = item_snippet.find('/') {
1061 let comment_hi = body_lo - BytePos(1);
1062 let comment_lo = item.span.lo() + BytePos(lo as u32);
1063 if comment_lo < comment_hi {
1064 match recover_missing_comment_in_span(
1065 mk_sp(comment_lo, comment_hi),
1066 Shape::indented(offset, context.config),
1068 last_line_width(&result),
1070 Some(ref missing_comment) if !missing_comment.is_empty() => {
1071 result.push_str(missing_comment);
1079 match context.config.brace_style() {
1080 _ if last_line_contains_single_line_comment(&result)
1081 || last_line_width(&result) + 2 > context.budget(offset.width()) =>
1083 result.push_str(&offset.to_string_with_newline(context.config));
1085 BraceStyle::AlwaysNextLine => {
1086 result.push_str(&offset.to_string_with_newline(context.config));
1088 BraceStyle::PreferSameLine => result.push(' '),
1089 BraceStyle::SameLineWhere => {
1090 if result.contains('\n')
1091 || (!generics.where_clause.predicates.is_empty() && !trait_items.is_empty())
1093 result.push_str(&offset.to_string_with_newline(context.config));
1101 let snippet = context.snippet(item.span);
1102 let open_pos = snippet.find_uncommented("{")? + 1;
1104 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1105 let mut visitor = FmtVisitor::from_context(context);
1106 visitor.block_indent = offset.block_only().block_indent(context.config);
1107 visitor.last_pos = item.span.lo() + BytePos(open_pos as u32);
1109 for item in trait_items {
1110 visitor.visit_trait_item(item);
1113 visitor.format_missing(item.span.hi() - BytePos(1));
1115 let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config);
1116 let outer_indent_str = offset.block_only().to_string_with_newline(context.config);
1118 result.push_str(&inner_indent_str);
1119 result.push_str(visitor.buffer.to_string().trim());
1120 result.push_str(&outer_indent_str);
1121 } else if result.contains('\n') {
1132 pub fn format_trait_alias(
1133 context: &RewriteContext,
1135 generics: &ast::Generics,
1136 ty_param_bounds: &ast::TyParamBounds,
1138 ) -> Option<String> {
1139 let alias = ident.name.as_str();
1140 // 6 = "trait ", 2 = " ="
1141 let g_shape = shape.offset_left(6)?.sub_width(2)?;
1142 let generics_str = rewrite_generics(context, &alias, generics, g_shape, generics.span)?;
1143 let lhs = format!("trait {} =", generics_str);
1145 rewrite_assign_rhs(context, lhs, ty_param_bounds, shape.sub_width(1)?).map(|s| s + ";")
1148 fn format_unit_struct(context: &RewriteContext, p: &StructParts, offset: Indent) -> Option<String> {
1149 let header_str = format_header(p.prefix, p.ident, p.vis);
1150 let generics_str = if let Some(generics) = p.generics {
1151 let hi = if generics.where_clause.predicates.is_empty() {
1154 generics.where_clause.span.hi()
1159 context.config.brace_style(),
1162 mk_sp(generics.span.lo(), hi),
1163 last_line_width(&header_str),
1168 Some(format!("{}{};", header_str, generics_str))
1171 pub fn format_struct_struct(
1172 context: &RewriteContext,
1173 struct_parts: &StructParts,
1174 fields: &[ast::StructField],
1176 one_line_width: Option<usize>,
1177 ) -> Option<String> {
1178 let mut result = String::with_capacity(1024);
1179 let span = struct_parts.span;
1181 let header_str = struct_parts.format_header();
1182 result.push_str(&header_str);
1184 let header_hi = span.lo() + BytePos(header_str.len() as u32);
1185 let body_lo = context.snippet_provider.span_after(span, "{");
1187 let generics_str = match struct_parts.generics {
1188 Some(g) => format_generics(
1191 context.config.brace_style(),
1192 if fields.is_empty() {
1193 BracePos::ForceSameLine
1198 mk_sp(header_hi, body_lo),
1199 last_line_width(&result),
1202 // 3 = ` {}`, 2 = ` {`.
1203 let overhead = if fields.is_empty() { 3 } else { 2 };
1204 if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty())
1205 || context.config.max_width() < overhead + result.len()
1207 format!("\n{}{{", offset.block_only().to_string(context.config))
1214 let overhead = if fields.is_empty() { 1 } else { 0 };
1215 let total_width = result.len() + generics_str.len() + overhead;
1216 if !generics_str.is_empty()
1217 && !generics_str.contains('\n')
1218 && total_width > context.config.max_width()
1221 result.push_str(&offset.to_string(context.config));
1222 result.push_str(generics_str.trim_left());
1224 result.push_str(&generics_str);
1227 if fields.is_empty() {
1228 let inner_span = mk_sp(body_lo, span.hi() - BytePos(1));
1229 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "", "}");
1230 return Some(result);
1234 let one_line_budget = context.budget(result.len() + 3 + offset.width());
1235 let one_line_budget =
1236 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1238 let items_str = rewrite_with_alignment(
1241 Shape::indented(offset, context.config).sub_width(1)?,
1242 mk_sp(body_lo, span.hi()),
1246 if !items_str.contains('\n')
1247 && !result.contains('\n')
1248 && items_str.len() <= one_line_budget
1249 && !last_line_contains_single_line_comment(&items_str)
1251 Some(format!("{} {} }}", result, items_str))
1257 .block_indent(context.config)
1258 .to_string(context.config),
1260 offset.to_string(context.config)
1265 fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos {
1267 ast::VisibilityKind::Crate(..) | ast::VisibilityKind::Restricted { .. } => vis.span.hi(),
1268 _ => default_span.lo(),
1272 // Format tuple or struct without any fields. We need to make sure that the comments
1273 // inside the delimiters are preserved.
1274 fn format_empty_struct_or_tuple(
1275 context: &RewriteContext,
1278 result: &mut String,
1282 // 3 = " {}" or "();"
1283 let used_width = last_line_used_width(&result, offset.width()) + 3;
1284 if used_width > context.config.max_width() {
1285 result.push_str(&offset.to_string_with_newline(context.config))
1287 result.push_str(opener);
1288 match rewrite_missing_comment(span, Shape::indented(offset, context.config), context) {
1289 Some(ref s) if s.is_empty() => (),
1291 if !is_single_line(s) || first_line_contains_single_line_comment(s) {
1292 let nested_indent_str = offset
1293 .block_indent(context.config)
1294 .to_string_with_newline(context.config);
1295 result.push_str(&nested_indent_str);
1298 if last_line_contains_single_line_comment(s) {
1299 result.push_str(&offset.to_string_with_newline(context.config));
1302 None => result.push_str(context.snippet(span)),
1304 result.push_str(closer);
1307 fn format_tuple_struct(
1308 context: &RewriteContext,
1309 struct_parts: &StructParts,
1310 fields: &[ast::StructField],
1312 ) -> Option<String> {
1313 let mut result = String::with_capacity(1024);
1314 let span = struct_parts.span;
1316 let header_str = struct_parts.format_header();
1317 result.push_str(&header_str);
1319 let body_lo = if fields.is_empty() {
1320 let lo = get_bytepos_after_visibility(struct_parts.vis, span);
1323 .span_after(mk_sp(lo, span.hi()), "(")
1327 let body_hi = if fields.is_empty() {
1330 .span_after(mk_sp(body_lo, span.hi()), ")")
1332 // This is a dirty hack to work around a missing `)` from the span of the last field.
1333 let last_arg_span = fields[fields.len() - 1].span;
1334 if context.snippet(last_arg_span).ends_with(')') {
1339 .span_after(mk_sp(last_arg_span.hi(), span.hi()), ")")
1343 let where_clause_str = match struct_parts.generics {
1345 let budget = context.budget(last_line_width(&header_str));
1346 let shape = Shape::legacy(budget, offset);
1347 let g_span = mk_sp(span.lo(), body_lo);
1348 let generics_str = rewrite_generics(context, "", generics, shape, g_span)?;
1349 result.push_str(&generics_str);
1351 let where_budget = context.budget(last_line_width(&result));
1352 let option = WhereClauseOption::new(true, false);
1353 rewrite_where_clause(
1355 &generics.where_clause,
1356 context.config.brace_style(),
1357 Shape::legacy(where_budget, offset.block_only()),
1358 Density::Compressed,
1366 None => "".to_owned(),
1369 if fields.is_empty() {
1370 let body_hi = context
1372 .span_before(mk_sp(body_lo, span.hi()), ")");
1373 let inner_span = mk_sp(body_lo, body_hi);
1374 format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "(", ")");
1376 let shape = Shape::indented(offset, context.config).sub_width(1)?;
1377 let fields = &fields.iter().collect::<Vec<_>>();
1378 result = overflow::rewrite_with_parens(
1384 context.config.width_heuristics().fn_call_width,
1389 if !where_clause_str.is_empty() && !where_clause_str.contains('\n')
1390 && (result.contains('\n')
1391 || offset.block_indent + result.len() + where_clause_str.len() + 1
1392 > context.config.max_width())
1394 // We need to put the where clause on a new line, but we didn't
1395 // know that earlier, so the where clause will not be indented properly.
1398 &(offset.block_only() + (context.config.tab_spaces() - 1)).to_string(context.config),
1401 result.push_str(&where_clause_str);
1406 pub fn rewrite_type_alias(
1407 context: &RewriteContext,
1411 generics: &ast::Generics,
1412 vis: &ast::Visibility,
1414 ) -> Option<String> {
1415 let mut result = String::with_capacity(128);
1417 result.push_str(&format_visibility(vis));
1418 result.push_str("type ");
1421 let g_shape = Shape::indented(indent, context.config)
1422 .offset_left(result.len())?
1425 context.snippet_provider.span_after(span, "type"),
1428 let generics_str = rewrite_generics(context, &ident.to_string(), generics, g_shape, g_span)?;
1429 result.push_str(&generics_str);
1431 let where_budget = context.budget(last_line_width(&result));
1432 let option = WhereClauseOption::snuggled(&result);
1433 let where_clause_str = rewrite_where_clause(
1435 &generics.where_clause,
1436 context.config.brace_style(),
1437 Shape::legacy(where_budget, indent),
1445 result.push_str(&where_clause_str);
1446 if where_clause_str.is_empty() {
1447 result.push_str(" =");
1449 result.push_str(&format!(
1451 indent.to_string_with_newline(context.config)
1456 let ty_shape = Shape::indented(indent, context.config).sub_width(1)?;
1457 rewrite_assign_rhs(context, result, ty, ty_shape).map(|s| s + ";")
1460 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1462 if config.space_before_colon() { " " } else { "" },
1463 if config.space_after_colon() { " " } else { "" },
1467 pub fn rewrite_struct_field_prefix(
1468 context: &RewriteContext,
1469 field: &ast::StructField,
1470 ) -> Option<String> {
1471 let vis = format_visibility(&field.vis);
1472 let type_annotation_spacing = type_annotation_spacing(context.config);
1473 Some(match field.ident {
1474 Some(name) => format!("{}{}{}:", vis, name, type_annotation_spacing.0),
1475 None => format!("{}", vis),
1479 impl Rewrite for ast::StructField {
1480 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1481 rewrite_struct_field(context, self, shape, 0)
1485 pub fn rewrite_struct_field(
1486 context: &RewriteContext,
1487 field: &ast::StructField,
1489 lhs_max_width: usize,
1490 ) -> Option<String> {
1491 if contains_skip(&field.attrs) {
1492 return Some(context.snippet(field.span()).to_owned());
1495 let type_annotation_spacing = type_annotation_spacing(context.config);
1496 let prefix = rewrite_struct_field_prefix(context, field)?;
1498 let attrs_str = field.attrs.rewrite(context, shape)?;
1499 let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str);
1500 let missing_span = if field.attrs.is_empty() {
1501 mk_sp(field.span.lo(), field.span.lo())
1503 mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo())
1505 let mut spacing = String::from(if field.ident.is_some() {
1506 type_annotation_spacing.1
1510 // Try to put everything on a single line.
1511 let attr_prefix = combine_strs_with_missing_comments(
1519 let overhead = last_line_width(&attr_prefix);
1520 let lhs_offset = lhs_max_width.saturating_sub(overhead);
1521 for _ in 0..lhs_offset {
1524 // In this extreme case we will be missing a space betweeen an attribute and a field.
1525 if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() {
1529 .offset_left(overhead + spacing.len())
1530 .and_then(|ty_shape| field.ty.rewrite(context, ty_shape));
1531 if let Some(ref ty) = orig_ty {
1532 if !ty.contains('\n') {
1533 return Some(attr_prefix + &spacing + ty);
1537 let is_prefix_empty = prefix.is_empty();
1538 // We must use multiline. We are going to put attributes and a field on different lines.
1539 let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, shape)?;
1540 // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct.
1541 let field_str = if is_prefix_empty {
1542 field_str.trim_left()
1546 combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false)
1549 pub struct StaticParts<'a> {
1551 vis: &'a ast::Visibility,
1554 mutability: ast::Mutability,
1555 expr_opt: Option<&'a ptr::P<ast::Expr>>,
1556 defaultness: Option<ast::Defaultness>,
1560 impl<'a> StaticParts<'a> {
1561 pub fn from_item(item: &'a ast::Item) -> Self {
1562 let (prefix, ty, mutability, expr) = match item.node {
1563 ast::ItemKind::Static(ref ty, mutability, ref expr) => ("static", ty, mutability, expr),
1564 ast::ItemKind::Const(ref ty, ref expr) => {
1565 ("const", ty, ast::Mutability::Immutable, expr)
1567 _ => unreachable!(),
1575 expr_opt: Some(expr),
1581 pub fn from_trait_item(ti: &'a ast::TraitItem) -> Self {
1582 let (ty, expr_opt) = match ti.node {
1583 ast::TraitItemKind::Const(ref ty, ref expr_opt) => (ty, expr_opt),
1584 _ => unreachable!(),
1588 vis: &DEFAULT_VISIBILITY,
1591 mutability: ast::Mutability::Immutable,
1592 expr_opt: expr_opt.as_ref(),
1598 pub fn from_impl_item(ii: &'a ast::ImplItem) -> Self {
1599 let (ty, expr) = match ii.node {
1600 ast::ImplItemKind::Const(ref ty, ref expr) => (ty, expr),
1601 _ => unreachable!(),
1608 mutability: ast::Mutability::Immutable,
1609 expr_opt: Some(expr),
1610 defaultness: Some(ii.defaultness),
1617 context: &RewriteContext,
1618 static_parts: &StaticParts,
1620 ) -> Option<String> {
1621 let colon = colon_spaces(
1622 context.config.space_before_colon(),
1623 context.config.space_after_colon(),
1625 let mut prefix = format!(
1627 format_visibility(static_parts.vis),
1628 static_parts.defaultness.map_or("", format_defaultness),
1629 static_parts.prefix,
1630 format_mutability(static_parts.mutability),
1636 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?;
1637 let ty_str = match static_parts.ty.rewrite(context, ty_shape) {
1638 Some(ty_str) => ty_str,
1640 if prefix.ends_with(' ') {
1643 let nested_indent = offset.block_indent(context.config);
1644 let nested_shape = Shape::indented(nested_indent, context.config);
1645 let ty_str = static_parts.ty.rewrite(context, nested_shape)?;
1648 nested_indent.to_string_with_newline(context.config),
1654 if let Some(expr) = static_parts.expr_opt {
1655 let lhs = format!("{}{} =", prefix, ty_str);
1657 let remaining_width = context.budget(offset.block_indent + 1);
1662 Shape::legacy(remaining_width, offset.block_only()),
1663 ).and_then(|res| recover_comment_removed(res, static_parts.span, context))
1664 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1666 Some(format!("{}{};", prefix, ty_str))
1670 pub fn rewrite_associated_type(
1672 ty_opt: Option<&ptr::P<ast::Ty>>,
1673 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1674 context: &RewriteContext,
1676 ) -> Option<String> {
1677 let prefix = format!("type {}", ident);
1679 let type_bounds_str = if let Some(bounds) = ty_param_bounds_opt {
1680 if bounds.is_empty() {
1684 let shape = Shape::indented(indent, context.config).offset_left(prefix.len() + 2)?;
1685 bounds.rewrite(context, shape).map(|s| format!(": {}", s))?
1691 if let Some(ty) = ty_opt {
1693 let shape = Shape::indented(indent, context.config).sub_width(1)?;
1694 let lhs = format!("{}{} =", prefix, type_bounds_str);
1695 rewrite_assign_rhs(context, lhs, &**ty, shape).map(|s| s + ";")
1697 Some(format!("{}{};", prefix, type_bounds_str))
1701 pub fn rewrite_associated_impl_type(
1703 defaultness: ast::Defaultness,
1704 ty_opt: Option<&ptr::P<ast::Ty>>,
1705 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1706 context: &RewriteContext,
1708 ) -> Option<String> {
1709 let result = rewrite_associated_type(ident, ty_opt, ty_param_bounds_opt, context, indent)?;
1712 ast::Defaultness::Default => Some(format!("default {}", result)),
1717 impl Rewrite for ast::FunctionRetTy {
1718 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1720 ast::FunctionRetTy::Default(_) => Some(String::new()),
1721 ast::FunctionRetTy::Ty(ref ty) => {
1722 let inner_width = shape.width.checked_sub(3)?;
1723 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1724 .map(|r| format!("-> {}", r))
1730 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1732 ast::TyKind::Infer => {
1733 let original = context.snippet(ty.span);
1740 impl Rewrite for ast::Arg {
1741 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1742 if is_named_arg(self) {
1743 let mut result = self
1745 .rewrite(context, Shape::legacy(shape.width, shape.indent))?;
1747 if !is_empty_infer(context, &*self.ty) {
1748 if context.config.space_before_colon() {
1749 result.push_str(" ");
1751 result.push_str(":");
1752 if context.config.space_after_colon() {
1753 result.push_str(" ");
1755 let overhead = last_line_width(&result);
1756 let max_width = shape.width.checked_sub(overhead)?;
1759 .rewrite(context, Shape::legacy(max_width, shape.indent))?;
1760 result.push_str(&ty_str);
1765 self.ty.rewrite(context, shape)
1770 fn rewrite_explicit_self(
1771 explicit_self: &ast::ExplicitSelf,
1773 context: &RewriteContext,
1774 ) -> Option<String> {
1775 match explicit_self.node {
1776 ast::SelfKind::Region(lt, m) => {
1777 let mut_str = format_mutability(m);
1780 let lifetime_str = l.rewrite(
1782 Shape::legacy(context.config.max_width(), Indent::empty()),
1784 Some(format!("&{} {}self", lifetime_str, mut_str))
1786 None => Some(format!("&{}self", mut_str)),
1789 ast::SelfKind::Explicit(ref ty, _) => {
1790 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1792 let mutability = explicit_self_mutability(&args[0]);
1793 let type_str = ty.rewrite(
1795 Shape::legacy(context.config.max_width(), Indent::empty()),
1800 format_mutability(mutability),
1804 ast::SelfKind::Value(_) => {
1805 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1807 let mutability = explicit_self_mutability(&args[0]);
1809 Some(format!("{}self", format_mutability(mutability)))
1814 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1815 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1816 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1817 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1824 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1825 if is_named_arg(arg) {
1832 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1834 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi(),
1835 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi(),
1836 _ => arg.ty.span.hi(),
1840 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1841 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1842 ident != symbol::keywords::Invalid.ident()
1848 // Return type is (result, force_new_line_for_brace)
1850 context: &RewriteContext,
1855 newline_brace: bool,
1857 ) -> Option<(String, bool)> {
1858 let mut force_new_line_for_brace = false;
1860 let where_clause = &fn_sig.generics.where_clause;
1862 let mut result = String::with_capacity(1024);
1863 result.push_str(&fn_sig.to_str(context));
1866 result.push_str("fn ");
1869 let overhead = if has_body && !newline_brace {
1876 let used_width = last_line_used_width(&result, indent.width());
1877 let one_line_budget = context.budget(used_width + overhead);
1879 width: one_line_budget,
1883 let fd = fn_sig.decl;
1884 let g_span = mk_sp(span.lo(), fd.output.span().lo());
1886 rewrite_generics(context, &ident.to_string(), fn_sig.generics, shape, g_span)?;
1887 result.push_str(&generics_str);
1889 let snuggle_angle_bracket = generics_str
1892 .map_or(false, |l| l.trim_left().len() == 1);
1894 // Note that the width and indent don't really matter, we'll re-layout the
1895 // return type later anyway.
1898 .rewrite(context, Shape::indented(indent, context.config))?;
1900 let multi_line_ret_str = ret_str.contains('\n');
1901 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1904 let (one_line_budget, multi_line_budget, mut arg_indent) = compute_budgets_for_args(
1915 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1916 one_line_budget, multi_line_budget, arg_indent
1919 // Check if vertical layout was forced.
1920 if one_line_budget == 0 {
1921 if snuggle_angle_bracket {
1924 result.push_str("(");
1925 if context.config.indent_style() == IndentStyle::Visual {
1926 result.push_str(&arg_indent.to_string_with_newline(context.config));
1933 // Skip `pub(crate)`.
1934 let lo_after_visibility = get_bytepos_after_visibility(&fn_sig.visibility, span);
1935 // A conservative estimation, to goal is to be over all parens in generics
1936 let args_start = fn_sig
1941 .map_or(lo_after_visibility, |param| param.span().hi());
1942 let args_end = if fd.inputs.is_empty() {
1945 .span_after(mk_sp(args_start, span.hi()), ")")
1947 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi());
1948 context.snippet_provider.span_after(last_span, ")")
1950 let args_span = mk_sp(
1953 .span_after(mk_sp(args_start, span.hi()), "("),
1956 let arg_str = rewrite_args(
1959 fd.get_self().as_ref(),
1966 generics_str.contains('\n'),
1969 let put_args_in_block = match context.config.indent_style() {
1970 IndentStyle::Block => arg_str.contains('\n') || arg_str.len() > one_line_budget,
1972 } && !fd.inputs.is_empty();
1974 let mut args_last_line_contains_comment = false;
1975 if put_args_in_block {
1976 arg_indent = indent.block_indent(context.config);
1977 result.push_str(&arg_indent.to_string_with_newline(context.config));
1978 result.push_str(&arg_str);
1979 result.push_str(&indent.to_string_with_newline(context.config));
1982 result.push_str(&arg_str);
1983 let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str);
1984 // Put the closing brace on the next line if it overflows the max width.
1986 if fd.inputs.is_empty() && used_width + 1 > context.config.max_width() {
1989 // If the last line of args contains comment, we cannot put the closing paren
1990 // on the same line.
1994 .map_or(false, |last_line| last_line.contains("//"))
1996 args_last_line_contains_comment = true;
1997 result.push_str(&arg_indent.to_string_with_newline(context.config));
2003 if let ast::FunctionRetTy::Ty(..) = fd.output {
2004 let ret_should_indent = match context.config.indent_style() {
2005 // If our args are block layout then we surely must have space.
2006 IndentStyle::Block if put_args_in_block || fd.inputs.is_empty() => false,
2007 _ if args_last_line_contains_comment => false,
2008 _ if result.contains('\n') || multi_line_ret_str => true,
2010 // If the return type would push over the max width, then put the return type on
2011 // a new line. With the +1 for the signature length an additional space between
2012 // the closing parenthesis of the argument and the arrow '->' is considered.
2013 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
2015 // If there is no where clause, take into account the space after the return type
2017 if where_clause.predicates.is_empty() {
2021 sig_length > context.config.max_width()
2024 let ret_indent = if ret_should_indent {
2025 let indent = if arg_str.is_empty() {
2026 // Aligning with non-existent args looks silly.
2027 force_new_line_for_brace = true;
2030 // FIXME: we might want to check that using the arg indent
2031 // doesn't blow our budget, and if it does, then fallback to
2032 // the where clause indent.
2036 result.push_str(&indent.to_string_with_newline(context.config));
2040 Indent::new(indent.block_indent, last_line_width(&result))
2043 if multi_line_ret_str || ret_should_indent {
2044 // Now that we know the proper indent and width, we need to
2045 // re-layout the return type.
2048 .rewrite(context, Shape::indented(ret_indent, context.config))?;
2049 result.push_str(&ret_str);
2051 result.push_str(&ret_str);
2054 // Comment between return type and the end of the decl.
2055 let snippet_lo = fd.output.span().hi();
2056 if where_clause.predicates.is_empty() {
2057 let snippet_hi = span.hi();
2058 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2059 // Try to preserve the layout of the original snippet.
2060 let original_starts_with_newline = snippet
2062 .map_or(false, |i| starts_with_newline(&snippet[i..]));
2063 let original_ends_with_newline = snippet
2064 .rfind(|c| c != ' ')
2065 .map_or(false, |i| snippet[i..].ends_with('\n'));
2066 let snippet = snippet.trim();
2067 if !snippet.is_empty() {
2068 result.push(if original_starts_with_newline {
2073 result.push_str(snippet);
2074 if original_ends_with_newline {
2075 force_new_line_for_brace = true;
2081 let pos_before_where = match fd.output {
2082 ast::FunctionRetTy::Default(..) => args_span.hi(),
2083 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi(),
2086 let is_args_multi_lined = arg_str.contains('\n');
2088 let option = WhereClauseOption::new(!has_body, put_args_in_block && ret_str.is_empty());
2089 let where_clause_str = rewrite_where_clause(
2092 context.config.brace_style(),
2093 Shape::indented(indent, context.config),
2099 is_args_multi_lined,
2101 // If there are neither where clause nor return type, we may be missing comments between
2103 if where_clause_str.is_empty() {
2104 if let ast::FunctionRetTy::Default(ret_span) = fd.output {
2105 match recover_missing_comment_in_span(
2106 mk_sp(args_span.hi(), ret_span.hi()),
2109 last_line_width(&result),
2111 Some(ref missing_comment) if !missing_comment.is_empty() => {
2112 result.push_str(missing_comment);
2113 force_new_line_for_brace = true;
2120 result.push_str(&where_clause_str);
2122 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2123 force_new_line_for_brace |= is_args_multi_lined && context.config.where_single_line();
2124 Some((result, force_new_line_for_brace))
2127 #[derive(Copy, Clone)]
2128 struct WhereClauseOption {
2129 suppress_comma: bool, // Force no trailing comma
2130 snuggle: bool, // Do not insert newline before `where`
2131 compress_where: bool, // Try single line where clause instead of vertical layout
2134 impl WhereClauseOption {
2135 pub fn new(suppress_comma: bool, snuggle: bool) -> WhereClauseOption {
2139 compress_where: false,
2143 pub fn snuggled(current: &str) -> WhereClauseOption {
2145 suppress_comma: false,
2146 snuggle: last_line_width(current) == 1,
2147 compress_where: false,
2151 pub fn suppress_comma(&mut self) {
2152 self.suppress_comma = true
2155 pub fn compress_where(&mut self) {
2156 self.compress_where = true
2159 pub fn snuggle(&mut self) {
2165 context: &RewriteContext,
2167 explicit_self: Option<&ast::ExplicitSelf>,
2168 one_line_budget: usize,
2169 multi_line_budget: usize,
2174 generics_str_contains_newline: bool,
2175 ) -> Option<String> {
2176 let mut arg_item_strs = args
2178 .map(|arg| arg.rewrite(context, Shape::legacy(multi_line_budget, arg_indent)))
2179 .collect::<Option<Vec<_>>>()?;
2181 // Account for sugary self.
2182 // FIXME: the comment for the self argument is dropped. This is blocked
2183 // on rust issue #27522.
2184 let min_args = explicit_self
2185 .and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
2186 .map_or(1, |self_str| {
2187 arg_item_strs[0] = self_str;
2191 // Comments between args.
2192 let mut arg_items = Vec::new();
2194 arg_items.push(ListItem::from_str(""));
2197 // FIXME(#21): if there are no args, there might still be a comment, but
2198 // without spans for the comment or parens, there is no chance of
2199 // getting it right. You also don't get to put a comment on self, unless
2201 if args.len() >= min_args || variadic {
2202 let comment_span_start = if min_args == 2 {
2203 let second_arg_start = if arg_has_pattern(&args[1]) {
2204 args[1].pat.span.lo()
2206 args[1].ty.span.lo()
2208 let reduced_span = mk_sp(span.lo(), second_arg_start);
2210 context.snippet_provider.span_after_last(reduced_span, ",")
2215 enum ArgumentKind<'a> {
2216 Regular(&'a ast::Arg),
2220 let variadic_arg = if variadic {
2221 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi(), span.hi());
2222 let variadic_start =
2223 context.snippet_provider.span_after(variadic_span, "...") - BytePos(3);
2224 Some(ArgumentKind::Variadic(variadic_start))
2229 let more_items = itemize_list(
2230 context.snippet_provider,
2231 args[min_args - 1..]
2233 .map(ArgumentKind::Regular)
2234 .chain(variadic_arg),
2238 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2239 ArgumentKind::Variadic(start) => start,
2242 ArgumentKind::Regular(arg) => arg.ty.span.hi(),
2243 ArgumentKind::Variadic(start) => start + BytePos(3),
2246 ArgumentKind::Regular(..) => None,
2247 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2254 arg_items.extend(more_items);
2257 let fits_in_one_line = !generics_str_contains_newline
2258 && (arg_items.is_empty()
2259 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2261 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2262 item.item = Some(arg);
2265 let last_line_ends_with_comment = arg_items
2268 .and_then(|item| item.post_comment.as_ref())
2269 .map_or(false, |s| s.trim().starts_with("//"));
2271 let (indent, trailing_comma) = match context.config.indent_style() {
2272 IndentStyle::Block if fits_in_one_line => {
2273 (indent.block_indent(context.config), SeparatorTactic::Never)
2275 IndentStyle::Block => (
2276 indent.block_indent(context.config),
2277 context.config.trailing_comma(),
2279 IndentStyle::Visual if last_line_ends_with_comment => {
2280 (arg_indent, context.config.trailing_comma())
2282 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2285 let tactic = definitive_tactic(
2287 context.config.fn_args_density().to_list_tactic(),
2291 let budget = match tactic {
2292 DefinitiveListTactic::Horizontal => one_line_budget,
2293 _ => multi_line_budget,
2296 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2298 let fmt = ListFormatting {
2301 trailing_separator: if variadic {
2302 SeparatorTactic::Never
2306 separator_place: SeparatorPlace::Back,
2307 shape: Shape::legacy(budget, indent),
2308 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2309 preserve_newline: true,
2310 config: context.config,
2313 write_list(&arg_items, &fmt)
2316 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2317 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2318 ident != symbol::keywords::Invalid.ident()
2324 fn compute_budgets_for_args(
2325 context: &RewriteContext,
2329 newline_brace: bool,
2331 force_vertical_layout: bool,
2332 ) -> Option<((usize, usize, Indent))> {
2334 "compute_budgets_for_args {} {:?}, {}, {}",
2340 // Try keeping everything on the same line.
2341 if !result.contains('\n') && !force_vertical_layout {
2342 // 2 = `()`, 3 = `() `, space is before ret_string.
2343 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2344 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2354 let one_line_budget = context.budget(used_space);
2356 if one_line_budget > 0 {
2358 let (indent, multi_line_budget) = match context.config.indent_style() {
2359 IndentStyle::Block => {
2360 let indent = indent.block_indent(context.config);
2361 (indent, context.budget(indent.width() + 1))
2363 IndentStyle::Visual => {
2364 let indent = indent + result.len() + 1;
2365 let multi_line_overhead = indent.width() + if newline_brace { 2 } else { 4 };
2366 (indent, context.budget(multi_line_overhead))
2370 return Some((one_line_budget, multi_line_budget, indent));
2374 // Didn't work. we must force vertical layout and put args on a newline.
2375 let new_indent = indent.block_indent(context.config);
2376 let used_space = match context.config.indent_style() {
2378 IndentStyle::Block => new_indent.width() + 1,
2379 // Account for `)` and possibly ` {`.
2380 IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 },
2382 Some((0, context.budget(used_space), new_indent))
2385 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2386 let predicate_count = where_clause.predicates.len();
2388 if config.where_single_line() && predicate_count == 1 {
2391 let brace_style = config.brace_style();
2393 brace_style == BraceStyle::AlwaysNextLine
2394 || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0)
2397 fn rewrite_generics(
2398 context: &RewriteContext,
2400 generics: &ast::Generics,
2403 ) -> Option<String> {
2404 // FIXME: convert bounds to where clauses where they get too big or if
2405 // there is a where clause at all.
2407 if generics.params.is_empty() {
2408 return Some(ident.to_owned());
2411 let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>();
2412 overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
2415 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2416 match config.indent_style() {
2417 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2418 IndentStyle::Block => {
2422 .block_indent(config.tab_spaces())
2423 .with_max_width(config)
2429 fn rewrite_where_clause_rfc_style(
2430 context: &RewriteContext,
2431 where_clause: &ast::WhereClause,
2434 span_end: Option<BytePos>,
2435 span_end_before_where: BytePos,
2436 where_clause_option: WhereClauseOption,
2437 is_args_multi_line: bool,
2438 ) -> Option<String> {
2439 let block_shape = shape.block().with_max_width(context.config);
2441 let (span_before, span_after) =
2442 missing_span_before_after_where(span_end_before_where, where_clause);
2443 let (comment_before, comment_after) =
2444 rewrite_comments_before_after_where(context, span_before, span_after, shape)?;
2446 let starting_newline = if where_clause_option.snuggle && comment_before.is_empty() {
2449 block_shape.indent.to_string_with_newline(context.config)
2452 let clause_shape = block_shape.block_left(context.config.tab_spaces())?;
2454 let clause_shape = clause_shape.sub_width(1)?;
2455 // each clause on one line, trailing comma (except if suppress_comma)
2456 let span_start = where_clause.predicates[0].span().lo();
2457 // If we don't have the start of the next span, then use the end of the
2458 // predicates, but that means we miss comments.
2459 let len = where_clause.predicates.len();
2460 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2461 let span_end = span_end.unwrap_or(end_of_preds);
2462 let items = itemize_list(
2463 context.snippet_provider,
2464 where_clause.predicates.iter(),
2467 |pred| pred.span().lo(),
2468 |pred| pred.span().hi(),
2469 |pred| pred.rewrite(context, clause_shape),
2474 let where_single_line = context.config.where_single_line() && len == 1 && !is_args_multi_line;
2475 let comma_tactic = if where_clause_option.suppress_comma || where_single_line {
2476 SeparatorTactic::Never
2478 context.config.trailing_comma()
2481 // shape should be vertical only and only if we have `where_single_line` option enabled
2482 // and the number of items of the where clause is equal to 1
2483 let shape_tactic = if where_single_line {
2484 DefinitiveListTactic::Horizontal
2486 DefinitiveListTactic::Vertical
2489 let fmt = ListFormatting {
2490 tactic: shape_tactic,
2492 trailing_separator: comma_tactic,
2493 separator_place: SeparatorPlace::Back,
2494 shape: clause_shape,
2495 ends_with_newline: true,
2496 preserve_newline: true,
2497 config: context.config,
2499 let preds_str = write_list(&items.collect::<Vec<_>>(), &fmt)?;
2501 let comment_separator = |comment: &str, shape: Shape| {
2502 if comment.is_empty() {
2505 shape.indent.to_string_with_newline(context.config)
2508 let newline_before_where = comment_separator(&comment_before, shape);
2509 let newline_after_where = comment_separator(&comment_after, clause_shape);
2512 let clause_sep = if where_clause_option.compress_where
2513 && comment_before.is_empty()
2514 && comment_after.is_empty()
2515 && !preds_str.contains('\n')
2516 && 6 + preds_str.len() <= shape.width || where_single_line
2520 clause_shape.indent.to_string_with_newline(context.config)
2523 "{}{}{}where{}{}{}{}",
2526 newline_before_where,
2527 newline_after_where,
2534 fn rewrite_where_clause(
2535 context: &RewriteContext,
2536 where_clause: &ast::WhereClause,
2537 brace_style: BraceStyle,
2541 span_end: Option<BytePos>,
2542 span_end_before_where: BytePos,
2543 where_clause_option: WhereClauseOption,
2544 is_args_multi_line: bool,
2545 ) -> Option<String> {
2546 if where_clause.predicates.is_empty() {
2547 return Some(String::new());
2550 if context.config.indent_style() == IndentStyle::Block {
2551 return rewrite_where_clause_rfc_style(
2557 span_end_before_where,
2558 where_clause_option,
2563 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2565 let offset = match context.config.indent_style() {
2566 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2567 // 6 = "where ".len()
2568 IndentStyle::Visual => shape.indent + extra_indent + 6,
2570 // FIXME: if indent_style != Visual, then the budgets below might
2571 // be out by a char or two.
2573 let budget = context.config.max_width() - offset.width();
2574 let span_start = where_clause.predicates[0].span().lo();
2575 // If we don't have the start of the next span, then use the end of the
2576 // predicates, but that means we miss comments.
2577 let len = where_clause.predicates.len();
2578 let end_of_preds = where_clause.predicates[len - 1].span().hi();
2579 let span_end = span_end.unwrap_or(end_of_preds);
2580 let items = itemize_list(
2581 context.snippet_provider,
2582 where_clause.predicates.iter(),
2585 |pred| pred.span().lo(),
2586 |pred| pred.span().hi(),
2587 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2592 let item_vec = items.collect::<Vec<_>>();
2593 // FIXME: we don't need to collect here
2594 let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget);
2596 let mut comma_tactic = context.config.trailing_comma();
2597 // Kind of a hack because we don't usually have trailing commas in where clauses.
2598 if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma {
2599 comma_tactic = SeparatorTactic::Never;
2602 let fmt = ListFormatting {
2605 trailing_separator: comma_tactic,
2606 separator_place: SeparatorPlace::Back,
2607 shape: Shape::legacy(budget, offset),
2608 ends_with_newline: tactic.ends_with_newline(context.config.indent_style()),
2609 preserve_newline: true,
2610 config: context.config,
2612 let preds_str = write_list(&item_vec, &fmt)?;
2614 let end_length = if terminator == "{" {
2615 // If the brace is on the next line we don't need to count it otherwise it needs two
2618 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2619 BraceStyle::PreferSameLine => 2,
2621 } else if terminator == "=" {
2626 if density == Density::Tall
2627 || preds_str.contains('\n')
2628 || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2632 (shape.indent + extra_indent).to_string(context.config),
2636 Some(format!(" where {}", preds_str))
2640 fn missing_span_before_after_where(
2641 before_item_span_end: BytePos,
2642 where_clause: &ast::WhereClause,
2644 let missing_span_before = mk_sp(before_item_span_end, where_clause.span.lo());
2646 let pos_after_where = where_clause.span.lo() + BytePos(5);
2647 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo());
2648 (missing_span_before, missing_span_after)
2651 fn rewrite_comments_before_after_where(
2652 context: &RewriteContext,
2653 span_before_where: Span,
2654 span_after_where: Span,
2656 ) -> Option<(String, String)> {
2657 let before_comment = rewrite_missing_comment(span_before_where, shape, context)?;
2658 let after_comment = rewrite_missing_comment(
2660 shape.block_indent(context.config.tab_spaces()),
2663 Some((before_comment, after_comment))
2666 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2667 format!("{}{}{}", format_visibility(vis), item_name, ident)
2670 #[derive(PartialEq, Eq, Clone, Copy)]
2678 context: &RewriteContext,
2679 generics: &ast::Generics,
2680 brace_style: BraceStyle,
2681 brace_pos: BracePos,
2685 ) -> Option<String> {
2686 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2687 let mut result = rewrite_generics(context, "", generics, shape, span)?;
2689 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2690 let budget = context.budget(last_line_used_width(&result, offset.width()));
2691 let mut option = WhereClauseOption::snuggled(&result);
2692 if brace_pos == BracePos::None {
2693 option.suppress_comma = true;
2695 // If the generics are not parameterized then generics.span.hi() == 0,
2696 // so we use span.lo(), which is the position after `struct Foo`.
2697 let span_end_before_where = if generics.is_parameterized() {
2702 let where_clause_str = rewrite_where_clause(
2704 &generics.where_clause,
2706 Shape::legacy(budget, offset.block_only()),
2710 span_end_before_where,
2714 result.push_str(&where_clause_str);
2715 brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine
2716 || (generics.where_clause.predicates.is_empty()
2717 && trimmed_last_line_width(&result) == 1)
2719 brace_pos == BracePos::ForceSameLine
2720 || trimmed_last_line_width(&result) == 1
2721 || brace_style != BraceStyle::AlwaysNextLine
2723 if brace_pos == BracePos::None {
2724 return Some(result);
2726 let total_used_width = last_line_used_width(&result, used_width);
2727 let remaining_budget = context.budget(total_used_width);
2728 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2729 // and hence we take the closer into account as well for one line budget.
2730 // We assume that the closer has the same length as the opener.
2731 let overhead = if brace_pos == BracePos::ForceSameLine {
2738 let forbid_same_line_brace = overhead > remaining_budget;
2739 if !forbid_same_line_brace && same_line_brace {
2743 result.push_str(&offset.block_only().to_string(context.config));
2750 impl Rewrite for ast::ForeignItem {
2751 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2752 let attrs_str = self.attrs.rewrite(context, shape)?;
2753 // Drop semicolon or it will be interpreted as comment.
2754 // FIXME: this may be a faulty span from libsyntax.
2755 let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1));
2757 let item_str = match self.node {
2758 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
2763 &FnSig::new(fn_decl, generics, self.vis.clone()),
2767 ).map(|(s, _)| format!("{};", s))
2769 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
2770 // FIXME(#21): we're dropping potential comments in between the
2771 // function keywords here.
2772 let vis = format_visibility(&self.vis);
2773 let mut_str = if is_mutable { "mut " } else { "" };
2774 let prefix = format!("{}static {}{}:", vis, mut_str, self.ident);
2776 rewrite_assign_rhs(context, prefix, &**ty, shape.sub_width(1)?).map(|s| s + ";")
2778 ast::ForeignItemKind::Ty => {
2779 let vis = format_visibility(&self.vis);
2780 Some(format!("{}type {};", vis, self.ident))
2782 ast::ForeignItemKind::Macro(ref mac) => {
2783 rewrite_macro(mac, None, context, shape, MacroPosition::Item)
2787 let missing_span = if self.attrs.is_empty() {
2788 mk_sp(self.span.lo(), self.span.lo())
2790 mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo())
2792 combine_strs_with_missing_comments(
2803 impl Rewrite for ast::GenericParam {
2804 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
2806 ast::GenericParam::Lifetime(ref lifetime_def) => lifetime_def.rewrite(context, shape),
2807 ast::GenericParam::Type(ref ty) => ty.rewrite(context, shape),
2812 /// Rewrite an inline mod.
2813 pub fn rewrite_mod(item: &ast::Item) -> String {
2814 let mut result = String::with_capacity(32);
2815 result.push_str(&*format_visibility(&item.vis));
2816 result.push_str("mod ");
2817 result.push_str(&item.ident.to_string());
2822 /// Rewrite `extern crate foo;` WITHOUT attributes.
2823 pub fn rewrite_extern_crate(context: &RewriteContext, item: &ast::Item) -> Option<String> {
2824 assert!(is_extern_crate(item));
2825 let new_str = context.snippet(item.span);
2826 Some(if contains_comment(new_str) {
2829 let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" ");
2830 String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";"))
2834 /// Returns true for `mod foo;`, false for `mod foo { .. }`.
2835 pub fn is_mod_decl(item: &ast::Item) -> bool {
2837 ast::ItemKind::Mod(ref m) => m.inner.hi() != item.span.hi(),
2842 pub fn is_use_item(item: &ast::Item) -> bool {
2844 ast::ItemKind::Use(_) => true,
2849 pub fn is_extern_crate(item: &ast::Item) -> bool {
2851 ast::ItemKind::ExternCrate(..) => true,