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.
13 use syntax::{abi, ast, ptr, symbol};
14 use syntax::ast::ImplItem;
15 use syntax::codemap::{BytePos, Span};
17 use {Indent, Shape, Spanned};
18 use codemap::SpanUtils;
19 use comment::{contains_comment, recover_comment_removed, rewrite_comment, FindUncommented};
20 use config::{BraceStyle, Config, Density, IndentStyle, ReturnIndent, Style};
21 use expr::{format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs,
22 rewrite_call_inner, ExprType};
23 use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting,
24 ListItem, ListTactic, SeparatorTactic};
25 use rewrite::{Rewrite, RewriteContext};
26 use types::join_bounds;
27 use utils::{colon_spaces, contains_skip, end_typaram, format_mutability, format_unsafety,
28 format_visibility, last_line_width, mk_sp, semicolon_for_expr, stmt_expr,
29 trim_newlines, trimmed_last_line_width, wrap_str};
30 use vertical::rewrite_with_alignment;
31 use visitor::FmtVisitor;
33 fn type_annotation_separator(config: &Config) -> &str {
35 config.space_before_type_annotation(),
36 config.space_after_type_annotation_colon(),
41 // Statements of the form
42 // let pat: ty = init;
43 impl Rewrite for ast::Local {
44 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
46 "Local::rewrite {:?} {} {:?}",
51 let mut result = "let ".to_owned();
54 let pat_shape = try_opt!(shape.offset_left(4));
56 let pat_shape = try_opt!(pat_shape.sub_width(1));
57 let pat_str = try_opt!(self.pat.rewrite(&context, pat_shape));
58 result.push_str(&pat_str);
60 // String that is placed within the assignment pattern and expression.
62 let mut infix = String::new();
64 if let Some(ref ty) = self.ty {
65 let separator = type_annotation_separator(context.config);
66 let indent = shape.indent + last_line_width(&result) + separator.len();
68 let budget = try_opt!(shape.width.checked_sub(indent.width() + 1));
69 let rewrite = try_opt!(ty.rewrite(context, Shape::legacy(budget, indent)));
71 infix.push_str(separator);
72 infix.push_str(&rewrite);
75 if self.init.is_some() {
82 result.push_str(&infix);
84 if let Some(ref ex) = self.init {
85 // 1 = trailing semicolon;
86 let nested_shape = try_opt!(shape.sub_width(1));
88 result = try_opt!(rewrite_assign_rhs(&context, result, ex, nested_shape));
96 // TODO convert to using rewrite style rather than visitor
97 // TODO format modules in this style
100 keyword: &'static str,
102 vis: Option<&'a ast::Visibility>,
103 body: Vec<BodyElement<'a>>,
108 fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Item<'a> {
109 let abi = if fm.abi == abi::Abi::C && !config.force_explicit_abi() {
112 format!("extern {}", fm.abi)
120 .map(|i| BodyElement::ForeignItem(i))
127 enum BodyElement<'a> {
128 // Stmt(&'a ast::Stmt),
129 // Field(&'a ast::Field),
130 // Variant(&'a ast::Variant),
131 // Item(&'a ast::Item),
132 ForeignItem(&'a ast::ForeignItem),
135 impl<'a> FmtVisitor<'a> {
136 fn format_item(&mut self, item: Item) {
137 self.buffer.push_str(&item.abi);
138 self.buffer.push_str(" ");
140 let snippet = self.snippet(item.span);
141 let brace_pos = snippet.find_uncommented("{").unwrap();
143 self.buffer.push_str("{");
144 if !item.body.is_empty() || contains_comment(&snippet[brace_pos..]) {
145 // FIXME: this skips comments between the extern keyword and the opening
147 self.last_pos = item.span.lo + BytePos(brace_pos as u32 + 1);
148 self.block_indent = self.block_indent.block_indent(self.config);
150 if item.body.is_empty() {
151 self.format_missing_no_indent(item.span.hi - BytePos(1));
152 self.block_indent = self.block_indent.block_unindent(self.config);
155 .push_str(&self.block_indent.to_string(self.config));
157 for item in &item.body {
158 self.format_body_element(item);
161 self.block_indent = self.block_indent.block_unindent(self.config);
162 self.format_missing_with_indent(item.span.hi - BytePos(1));
166 self.buffer.push_str("}");
167 self.last_pos = item.span.hi;
170 fn format_body_element(&mut self, element: &BodyElement) {
172 BodyElement::ForeignItem(ref item) => self.format_foreign_item(item),
176 pub fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) {
177 let item = Item::from_foreign_mod(fm, span, self.config);
178 self.format_item(item);
181 fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
182 self.format_missing_with_indent(item.span.lo);
183 // Drop semicolon or it will be interpreted as comment.
184 // FIXME: this may be a faulty span from libsyntax.
185 let span = mk_sp(item.span.lo, item.span.hi - BytePos(1));
188 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
189 let indent = self.block_indent;
190 let rewrite = rewrite_fn_base(
196 ast::Unsafety::Normal,
197 ast::Constness::NotConst,
198 ast::Defaultness::Final,
199 // These are not actually rust functions,
200 // but we format them as such.
210 Some((new_fn, _)) => {
211 self.buffer.push_str(&new_fn);
212 self.buffer.push_str(";");
214 None => self.format_missing(item.span.hi),
217 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
218 // FIXME(#21): we're dropping potential comments in between the
219 // function keywords here.
220 let vis = format_visibility(&item.vis);
221 let mut_str = if is_mutable { "mut " } else { "" };
222 let prefix = format!("{}static {}{}: ", vis, mut_str, item.ident);
223 let offset = self.block_indent + prefix.len();
225 let shape = Shape::indented(offset, self.config).sub_width(1).unwrap();
226 let rewrite = ty.rewrite(&self.get_context(), shape);
230 self.buffer.push_str(&prefix);
231 self.buffer.push_str(&result);
232 self.buffer.push_str(";");
234 None => self.format_missing(item.span.hi),
239 self.last_pos = item.span.hi;
247 generics: &ast::Generics,
248 unsafety: ast::Unsafety,
249 constness: ast::Constness,
250 defaultness: ast::Defaultness,
252 vis: &ast::Visibility,
255 ) -> Option<String> {
256 let mut newline_brace = newline_for_brace(self.config, &generics.where_clause);
257 let context = self.get_context();
259 let block_snippet = self.snippet(mk_sp(block.span.lo, block.span.hi));
260 let has_body = !block_snippet[1..block_snippet.len() - 1].trim().is_empty() ||
261 !context.config.fn_empty_single_line();
263 let (mut result, force_newline_brace) = try_opt!(rewrite_fn_base(
280 if force_newline_brace {
281 newline_brace = true;
282 } else if self.config.fn_brace_style() != BraceStyle::AlwaysNextLine &&
283 !result.contains('\n')
285 newline_brace = false;
288 // Prepare for the function body by possibly adding a newline and
290 // FIXME we'll miss anything between the end of the signature and the
291 // start of the body, but we need more spans from the compiler to solve
295 result.push_str(&indent.to_string(self.config));
300 self.single_line_fn(&result, block).or_else(|| Some(result))
303 pub fn rewrite_required_fn(
307 sig: &ast::MethodSig,
309 ) -> Option<String> {
310 // Drop semicolon or it will be interpreted as comment.
311 let span = mk_sp(span.lo, span.hi - BytePos(1));
312 let context = self.get_context();
314 let (mut result, _) = try_opt!(rewrite_fn_base(
322 ast::Defaultness::Final,
324 &ast::Visibility::Inherited,
331 // Re-attach semicolon
337 fn single_line_fn(&self, fn_str: &str, block: &ast::Block) -> Option<String> {
338 if fn_str.contains('\n') {
342 let codemap = self.get_context().codemap;
344 if self.config.fn_empty_single_line() && is_empty_block(block, codemap) &&
345 self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width()
347 return Some(format!("{}{{}}", fn_str));
350 if self.config.fn_single_line() && is_simple_block_stmt(block, codemap) {
352 if let Some(ref stmt) = block.stmts.first() {
353 match stmt_expr(stmt) {
355 let suffix = if semicolon_for_expr(&self.get_context(), e) {
365 Shape::indented(self.block_indent, self.config),
366 ).map(|s| s + suffix)
367 .or_else(|| Some(self.snippet(e.span)))
369 None => stmt.rewrite(
371 Shape::indented(self.block_indent, self.config),
379 if let Some(res) = rewrite {
380 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
381 if !res.contains('\n') && width <= self.config.max_width() {
382 return Some(format!("{}{{ {} }}", fn_str, res));
393 vis: &ast::Visibility,
394 enum_def: &ast::EnumDef,
395 generics: &ast::Generics,
398 let enum_header = format_header("enum ", ident, vis);
399 self.buffer.push_str(&enum_header);
401 let enum_snippet = self.snippet(span);
402 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
403 let body_start = span.lo + BytePos(brace_pos as u32 + 1);
404 let generics_str = format_generics(
409 self.config.item_brace_style(),
410 enum_def.variants.is_empty(),
412 mk_sp(span.lo, body_start),
413 last_line_width(&enum_header),
415 self.buffer.push_str(&generics_str);
417 self.last_pos = body_start;
419 self.block_indent = self.block_indent.block_indent(self.config);
420 let variant_list = self.format_variant_list(enum_def, body_start, span.hi - BytePos(1));
422 Some(ref body_str) => self.buffer.push_str(body_str),
423 None => if contains_comment(&enum_snippet[brace_pos..]) {
424 self.format_missing_no_indent(span.hi - BytePos(1))
426 self.format_missing(span.hi - BytePos(1))
429 self.block_indent = self.block_indent.block_unindent(self.config);
431 if variant_list.is_some() || contains_comment(&enum_snippet[brace_pos..]) {
433 .push_str(&self.block_indent.to_string(self.config));
435 self.buffer.push_str("}");
436 self.last_pos = span.hi;
439 // Format the body of an enum definition
440 fn format_variant_list(
442 enum_def: &ast::EnumDef,
445 ) -> Option<String> {
446 if enum_def.variants.is_empty() {
449 let mut result = String::with_capacity(1024);
451 let indentation = self.block_indent.to_string(self.config);
452 result.push_str(&indentation);
454 let items = itemize_list(
456 enum_def.variants.iter(),
458 |f| if !f.node.attrs.is_empty() {
459 f.node.attrs[0].span.lo
464 |f| self.format_variant(f),
469 let shape = Shape::indented(self.block_indent, self.config)
472 let fmt = ListFormatting {
473 tactic: DefinitiveListTactic::Vertical,
475 trailing_separator: self.config.trailing_comma(),
477 ends_with_newline: true,
481 let list = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
482 result.push_str(&list);
487 // Variant of an enum.
488 fn format_variant(&self, field: &ast::Variant) -> Option<String> {
489 if contains_skip(&field.node.attrs) {
490 let lo = field.node.attrs[0].span.lo;
491 let span = mk_sp(lo, field.span.hi);
492 return Some(self.snippet(span));
495 let context = self.get_context();
496 let indent = self.block_indent;
497 let mut result = try_opt!(
501 .rewrite(&context, Shape::indented(indent, self.config))
503 if !result.is_empty() {
505 width: context.config.max_width(),
506 indent: self.block_indent,
507 offset: self.block_indent.alignment,
509 let missing_comment = rewrite_missing_comment_on_field(
512 field.node.attrs[field.node.attrs.len() - 1].span.hi,
515 ).unwrap_or(String::new());
516 result.push_str(&missing_comment);
519 let variant_body = match field.node.data {
520 ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => {
521 // FIXME: Should limit the width, as we have a trailing comma
526 &ast::Visibility::Inherited,
531 Some(self.config.struct_variant_width()),
534 ast::VariantData::Unit(..) => {
535 let tag = if let Some(ref expr) = field.node.disr_expr {
536 format!("{} = {}", field.node.name, self.snippet(expr.span))
538 field.node.name.to_string()
543 self.config.max_width(),
544 Shape::indented(indent, self.config),
549 if let Some(variant_str) = variant_body {
550 result.push_str(&variant_str);
559 context: &RewriteContext,
562 where_span_end: Option<BytePos>,
563 ) -> Option<String> {
564 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
565 let mut result = String::new();
566 let ref_and_type = try_opt!(format_impl_ref_and_type(context, item, offset));
567 result.push_str(&ref_and_type);
569 let where_budget = if result.contains('\n') {
570 context.config.max_width()
575 .checked_sub(last_line_width(&result))
578 let where_clause_str = try_opt!(rewrite_where_clause(
580 &generics.where_clause,
581 context.config.item_brace_style(),
582 Shape::legacy(where_budget, offset.block_only()),
583 context.config.where_density(),
586 last_line_width(&ref_and_type) == 1,
592 if try_opt!(is_impl_single_line(
599 result.push_str(&where_clause_str);
600 if where_clause_str.contains('\n') {
601 let white_space = offset.to_string(context.config);
602 result.push_str(&format!("\n{}{{\n{}}}", &white_space, &white_space));
604 result.push_str(" {}");
609 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
611 let width = offset.block_indent + context.config.tab_spaces() - 1;
612 let where_indent = Indent::new(0, width);
613 result.push_str(&where_indent.to_string(context.config));
615 result.push_str(&where_clause_str);
617 match context.config.item_brace_style() {
618 BraceStyle::AlwaysNextLine => {
620 result.push_str(&offset.to_string(context.config));
622 BraceStyle::PreferSameLine => result.push(' '),
623 BraceStyle::SameLineWhere => if !where_clause_str.is_empty() {
625 result.push_str(&offset.to_string(context.config));
633 let snippet = context.snippet(item.span);
634 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
636 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
637 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
638 visitor.block_indent = offset.block_only().block_indent(context.config);
639 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
642 visitor.visit_impl_item(item);
645 visitor.format_missing(item.span.hi - BytePos(1));
647 let inner_indent_str = visitor.block_indent.to_string(context.config);
648 let outer_indent_str = offset.block_only().to_string(context.config);
651 result.push_str(&inner_indent_str);
652 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
654 result.push_str(&outer_indent_str);
657 if result.chars().last().unwrap() == '{' {
659 result.push_str(&offset.to_string(context.config));
669 fn is_impl_single_line(
670 context: &RewriteContext,
673 where_clause_str: &str,
676 let snippet = context.snippet(item.span);
677 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
680 context.config.impl_empty_single_line() && items.is_empty() &&
681 result.len() + where_clause_str.len() <= context.config.max_width() &&
682 !contains_comment(&snippet[open_pos..]),
686 fn format_impl_ref_and_type(
687 context: &RewriteContext,
690 ) -> Option<String> {
691 if let ast::ItemKind::Impl(
701 let mut result = String::new();
703 result.push_str(&format_visibility(&item.vis));
704 result.push_str(format_unsafety(unsafety));
705 result.push_str("impl");
707 let lo = context.codemap.span_after(item.span, "impl");
708 let hi = match *trait_ref {
709 Some(ref tr) => tr.path.span.lo,
710 None => self_ty.span.lo,
712 let shape = try_opt!(generics_shape_from_config(
714 Shape::indented(offset + last_line_width(&result), context.config),
717 let one_line_budget = try_opt!(shape.width.checked_sub(last_line_width(&result) + 2));
718 let generics_str = try_opt!(rewrite_generics_inner(
726 let polarity_str = if polarity == ast::ImplPolarity::Negative {
732 if let Some(ref trait_ref) = *trait_ref {
733 let result_len = result.len();
734 if let Some(trait_ref_str) = rewrite_trait_ref(
743 result.push_str(&trait_ref_str);
745 let generics_str = try_opt!(rewrite_generics_inner(
752 result.push_str(&try_opt!(rewrite_trait_ref(
763 result.push_str(&generics_str);
766 // Try to put the self type in a single line.
768 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
769 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
770 // If there is no where clause adapt budget for type formatting to take space and curly
771 // brace into account.
772 match context.config.item_brace_style() {
773 BraceStyle::AlwaysNextLine => 0,
779 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
780 // 1 = space before the type.
784 .checked_sub(used_space + 1)
786 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
787 if !self_ty_str.contains('\n') {
788 if trait_ref.is_some() {
789 result.push_str(" for ");
793 result.push_str(&self_ty_str);
798 // Couldn't fit the self type on a single line, put it on a new line.
800 // Add indentation of one additional tab.
801 let new_line_offset = offset.block_indent(context.config);
802 result.push_str(&new_line_offset.to_string(context.config));
803 if trait_ref.is_some() {
804 result.push_str("for ");
806 let budget = context.config.max_width() - last_line_width(&result);
807 let type_offset = match context.config.where_style() {
808 Style::Legacy => new_line_offset + trait_ref_overhead,
809 Style::Rfc => new_line_offset,
811 result.push_str(&*try_opt!(
812 self_ty.rewrite(context, Shape::legacy(budget, type_offset))
820 fn rewrite_trait_ref(
821 context: &RewriteContext,
822 trait_ref: &ast::TraitRef,
828 ) -> Option<String> {
829 // 1 = space between generics and trait_ref
830 let used_space = 1 + polarity_str.len() +
831 if generics_str.contains('\n') {
832 last_line_width(&generics_str)
834 result_len + generics_str.len()
836 let shape = Shape::indented(offset + used_space, context.config);
837 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
838 if !(retry && trait_ref_str.contains('\n')) {
847 // We could not make enough space for trait_ref, so put it on new line.
849 let offset = offset.block_indent(context.config);
850 let shape = Shape::indented(offset, context.config);
851 let trait_ref_str = try_opt!(trait_ref.rewrite(context, shape));
855 &offset.to_string(context.config),
864 pub fn format_struct(
865 context: &RewriteContext,
868 vis: &ast::Visibility,
869 struct_def: &ast::VariantData,
870 generics: Option<&ast::Generics>,
873 one_line_width: Option<usize>,
874 ) -> Option<String> {
876 ast::VariantData::Unit(..) => Some(format_unit_struct(item_name, ident, vis)),
877 ast::VariantData::Tuple(ref fields, _) => format_tuple_struct(
887 ast::VariantData::Struct(ref fields, _) => format_struct_struct(
901 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
902 if let ast::ItemKind::Trait(unsafety, ref generics, ref type_param_bounds, ref trait_items) =
905 let mut result = String::new();
906 let header = format!(
908 format_visibility(&item.vis),
909 format_unsafety(unsafety),
913 result.push_str(&header);
915 let body_lo = context.codemap.span_after(item.span, "{");
917 let shape = Shape::indented(offset + last_line_width(&result), context.config);
918 let generics_str = try_opt!(rewrite_generics(
922 mk_sp(item.span.lo, body_lo),
924 result.push_str(&generics_str);
926 let trait_bound_str = try_opt!(rewrite_trait_bounds(
929 Shape::indented(offset, context.config),
931 // If the trait, generics, and trait bound cannot fit on the same line,
932 // put the trait bounds on an indented new line
933 if offset.width() + last_line_width(&result) + trait_bound_str.len() >
934 context.config.comment_width()
937 let trait_indent = offset.block_only().block_indent(context.config);
938 result.push_str(&trait_indent.to_string(context.config));
940 result.push_str(&trait_bound_str);
942 let has_body = !trait_items.is_empty();
944 let where_density = if (context.config.where_density() == Density::Compressed &&
945 (!result.contains('\n') ||
946 context.config.fn_args_layout() == IndentStyle::Block)) ||
947 (context.config.fn_args_layout() == IndentStyle::Block && result.is_empty()) ||
948 (context.config.where_density() == Density::CompressedIfEmpty && !has_body &&
949 !result.contains('\n'))
956 let where_budget = try_opt!(
960 .checked_sub(last_line_width(&result))
962 let pos_before_where = if type_param_bounds.is_empty() {
963 // We do not use this, so it does not matter
966 type_param_bounds[type_param_bounds.len() - 1].span().hi
968 let where_clause_str = try_opt!(rewrite_where_clause(
970 &generics.where_clause,
971 context.config.item_brace_style(),
972 Shape::legacy(where_budget, offset.block_only()),
976 trait_bound_str.is_empty() && last_line_width(&generics_str) == 1,
981 // If the where clause cannot fit on the same line,
982 // put the where clause on a new line
983 if !where_clause_str.contains('\n') &&
984 last_line_width(&result) + where_clause_str.len() + offset.width() >
985 context.config.comment_width()
988 let width = offset.block_indent + context.config.tab_spaces() - 1;
989 let where_indent = Indent::new(0, width);
990 result.push_str(&where_indent.to_string(context.config));
992 result.push_str(&where_clause_str);
994 match context.config.item_brace_style() {
995 BraceStyle::AlwaysNextLine => {
997 result.push_str(&offset.to_string(context.config));
999 BraceStyle::PreferSameLine => result.push(' '),
1000 BraceStyle::SameLineWhere => if !where_clause_str.is_empty() &&
1001 (!trait_items.is_empty() || result.contains('\n'))
1004 result.push_str(&offset.to_string(context.config));
1011 let snippet = context.snippet(item.span);
1012 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
1014 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1015 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
1016 visitor.block_indent = offset.block_only().block_indent(context.config);
1017 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
1019 for item in trait_items {
1020 visitor.visit_trait_item(item);
1023 visitor.format_missing(item.span.hi - BytePos(1));
1025 let inner_indent_str = visitor.block_indent.to_string(context.config);
1026 let outer_indent_str = offset.block_only().to_string(context.config);
1029 result.push_str(&inner_indent_str);
1030 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
1032 result.push_str(&outer_indent_str);
1033 } else if result.contains('\n') {
1044 fn format_unit_struct(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
1045 format!("{};", format_header(item_name, ident, vis))
1048 pub fn format_struct_struct(
1049 context: &RewriteContext,
1052 vis: &ast::Visibility,
1053 fields: &[ast::StructField],
1054 generics: Option<&ast::Generics>,
1057 one_line_width: Option<usize>,
1058 ) -> Option<String> {
1059 let mut result = String::with_capacity(1024);
1061 let header_str = format_header(item_name, ident, vis);
1062 result.push_str(&header_str);
1064 let body_lo = context.codemap.span_after(span, "{");
1066 let generics_str = match generics {
1067 Some(g) => try_opt!(format_generics(
1072 context.config.item_brace_style(),
1075 mk_sp(span.lo, body_lo),
1076 last_line_width(&result),
1079 // 3 = ` {}`, 2 = ` {`.
1080 let overhead = if fields.is_empty() { 3 } else { 2 };
1081 if (context.config.item_brace_style() == BraceStyle::AlwaysNextLine &&
1082 !fields.is_empty()) ||
1086 .checked_sub(result.len())
1087 .unwrap_or(0) < overhead
1089 format!("\n{}{{", offset.block_only().to_string(context.config))
1096 let overhead = if fields.is_empty() { 1 } else { 0 };
1097 let max_len = context.config.max_width() - offset.width();
1098 if !generics_str.contains('\n') && result.len() + generics_str.len() + overhead > max_len {
1100 result.push_str(&offset
1101 .block_indent(context.config)
1102 .to_string(context.config));
1103 result.push_str(&generics_str.trim_left());
1105 result.push_str(&generics_str);
1108 if fields.is_empty() {
1109 let snippet = context.snippet(mk_sp(body_lo, span.hi - BytePos(1)));
1110 if snippet.trim().is_empty() {
1112 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1114 result.push_str(&snippet.trim_right());
1116 result.push_str(&offset.to_string(context.config));
1118 result.push_str(&snippet);
1121 return Some(result);
1124 let items_str = try_opt!(rewrite_with_alignment(
1127 Shape::indented(offset, context.config),
1128 mk_sp(body_lo, span.hi),
1129 one_line_width.unwrap_or(0),
1132 if one_line_width.is_some() && !items_str.contains('\n') {
1133 Some(format!("{} {} }}", result, items_str))
1139 .block_indent(context.config)
1140 .to_string(context.config),
1142 offset.to_string(context.config)
1147 fn format_tuple_struct(
1148 context: &RewriteContext,
1151 vis: &ast::Visibility,
1152 fields: &[ast::StructField],
1153 generics: Option<&ast::Generics>,
1156 ) -> Option<String> {
1157 let mut result = String::with_capacity(1024);
1159 let header_str = format_header(item_name, ident, vis);
1160 result.push_str(&header_str);
1162 let body_lo = if fields.is_empty() {
1163 context.codemap.span_after(span, "(")
1167 let body_hi = if fields.is_empty() {
1168 context.codemap.span_after(span, ")")
1170 // This is a dirty hack to work around a missing `)` from the span of the last field.
1171 let last_arg_span = fields[fields.len() - 1].span;
1172 if context.snippet(last_arg_span).ends_with(")") {
1177 .span_after(mk_sp(last_arg_span.hi, span.hi), ")")
1181 let where_clause_str = match generics {
1183 let budget = context.budget(last_line_width(&header_str));
1184 let shape = Shape::legacy(budget, offset);
1185 let g_span = mk_sp(span.lo, body_lo);
1186 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1187 result.push_str(&generics_str);
1189 let where_budget = context.budget(last_line_width(&result));
1190 try_opt!(rewrite_where_clause(
1192 &generics.where_clause,
1193 context.config.item_brace_style(),
1194 Shape::legacy(where_budget, offset.block_only()),
1195 Density::Compressed,
1204 None => "".to_owned(),
1207 if fields.is_empty() {
1209 let used_width = if result.contains('\n') {
1210 last_line_width(&result) + 3
1212 offset.width() + result.len() + 3
1214 if used_width > context.config.max_width() {
1216 result.push_str(&offset
1217 .block_indent(context.config)
1218 .to_string(context.config))
1221 let snippet = context.snippet(mk_sp(body_lo, context.codemap.span_before(span, ")")));
1222 if snippet.is_empty() {
1224 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1225 result.push_str(&snippet.trim_right());
1227 result.push_str(&offset.to_string(context.config));
1229 result.push_str(&snippet);
1234 let body = try_opt!(
1238 &fields.iter().map(|field| field).collect::<Vec<_>>()[..],
1240 Shape::legacy(context.budget(last_line_width(&result) + 3), offset),
1241 context.config.fn_call_width(),
1245 result.push_str(&body);
1248 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') &&
1249 (result.contains('\n') ||
1250 offset.block_indent + result.len() + where_clause_str.len() + 1 >
1251 context.config.max_width())
1253 // We need to put the where clause on a new line, but we didn't
1254 // know that earlier, so the where clause will not be indented properly.
1256 result.push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1257 .to_string(context.config));
1259 result.push_str(&where_clause_str);
1264 pub fn rewrite_type_alias(
1265 context: &RewriteContext,
1269 generics: &ast::Generics,
1270 vis: &ast::Visibility,
1272 ) -> Option<String> {
1273 let mut result = String::new();
1275 result.push_str(&format_visibility(vis));
1276 result.push_str("type ");
1277 result.push_str(&ident.to_string());
1280 let shape = try_opt!(Shape::indented(indent + result.len(), context.config).sub_width(2));
1281 let g_span = mk_sp(context.codemap.span_after(span, "type"), ty.span.lo);
1282 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1283 result.push_str(&generics_str);
1285 let where_budget = try_opt!(
1289 .checked_sub(last_line_width(&result))
1291 let where_clause_str = try_opt!(rewrite_where_clause(
1293 &generics.where_clause,
1294 context.config.item_brace_style(),
1295 Shape::legacy(where_budget, indent),
1296 context.config.where_density(),
1304 result.push_str(&where_clause_str);
1305 result.push_str(" = ");
1307 let line_width = last_line_width(&result);
1308 // This checked_sub may fail as the extra space after '=' is not taken into account
1309 // In that case the budget is set to 0 which will make ty.rewrite retry on a new line
1310 let budget = context
1313 .checked_sub(indent.width() + line_width + ";".len())
1315 let type_indent = indent + line_width;
1316 // Try to fit the type on the same line
1317 let ty_str = try_opt!(
1318 ty.rewrite(context, Shape::legacy(budget, type_indent))
1320 // The line was too short, try to put the type on the next line
1322 // Remove the space after '='
1324 let type_indent = indent.block_indent(context.config);
1326 result.push_str(&type_indent.to_string(context.config));
1327 let budget = try_opt!(
1331 .checked_sub(type_indent.width() + ";".len())
1333 ty.rewrite(context, Shape::legacy(budget, type_indent))
1336 result.push_str(&ty_str);
1337 result.push_str(";");
1341 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1343 if config.space_before_type_annotation() {
1348 if config.space_after_type_annotation_colon() {
1356 fn rewrite_missing_comment_on_field(
1357 context: &RewriteContext,
1361 result: &mut String,
1362 ) -> Option<String> {
1363 let possibly_comment_snippet = context.snippet(mk_sp(lo, hi));
1364 let newline_index = possibly_comment_snippet.find('\n');
1365 let comment_index = possibly_comment_snippet.find('/');
1366 match (newline_index, comment_index) {
1367 (Some(i), Some(j)) if i > j => result.push(' '),
1370 result.push_str(&shape.indent.to_string(context.config));
1373 let trimmed = possibly_comment_snippet.trim();
1374 if trimmed.is_empty() {
1377 rewrite_comment(trimmed, false, shape, context.config).map(|s| {
1378 format!("{}\n{}", s, shape.indent.to_string(context.config))
1383 pub fn rewrite_struct_field_prefix(
1384 context: &RewriteContext,
1385 field: &ast::StructField,
1387 ) -> Option<String> {
1388 let vis = format_visibility(&field.vis);
1389 let mut attr_str = try_opt!(
1392 .rewrite(context, Shape::indented(shape.indent, context.config))
1394 // Try format missing comments after attributes
1395 let missing_comment = if !field.attrs.is_empty() {
1396 rewrite_missing_comment_on_field(
1399 field.attrs[field.attrs.len() - 1].span.hi,
1402 ).unwrap_or(String::new())
1407 let type_annotation_spacing = type_annotation_spacing(context.config);
1408 Some(match field.ident {
1409 Some(name) => format!(
1415 type_annotation_spacing.0
1417 None => format!("{}{}{}", attr_str, missing_comment, vis),
1421 fn rewrite_struct_field_type(
1422 context: &RewriteContext,
1423 last_line_width: usize,
1424 field: &ast::StructField,
1427 ) -> Option<String> {
1428 let ty_shape = try_opt!(shape.offset_left(last_line_width + spacing.len()));
1431 .rewrite(context, ty_shape)
1432 .map(|ty| format!("{}{}", spacing, ty))
1435 impl Rewrite for ast::StructField {
1436 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1437 rewrite_struct_field(context, self, shape, 0)
1441 pub fn rewrite_struct_field(
1442 context: &RewriteContext,
1443 field: &ast::StructField,
1445 lhs_max_width: usize,
1446 ) -> Option<String> {
1447 if contains_skip(&field.attrs) {
1448 let span = context.snippet(mk_sp(field.attrs[0].span.lo, field.span.hi));
1449 return wrap_str(span, context.config.max_width(), shape);
1452 let type_annotation_spacing = type_annotation_spacing(context.config);
1453 let prefix = try_opt!(rewrite_struct_field_prefix(context, field, shape));
1455 // Try to put everything on a single line.
1456 let last_line_width = last_line_width(&prefix);
1457 let mut spacing = String::from(if field.ident.is_some() {
1458 type_annotation_spacing.1
1462 let lhs_offset = lhs_max_width.checked_sub(last_line_width).unwrap_or(0);
1463 for _ in 0..lhs_offset {
1466 let ty_rewritten = rewrite_struct_field_type(context, last_line_width, field, &spacing, shape);
1467 if let Some(ref ty) = ty_rewritten {
1468 if !ty.contains('\n') {
1469 return Some(prefix + &ty);
1473 // We must use multiline.
1474 let type_offset = shape.indent.block_indent(context.config);
1475 let rewrite_type_in_next_line = || {
1478 .rewrite(context, Shape::indented(type_offset, context.config))
1481 match ty_rewritten {
1482 // If we start from the next line and type fits in a single line, then do so.
1483 Some(ref ty) => match rewrite_type_in_next_line() {
1484 Some(ref new_ty) if !new_ty.contains('\n') => Some(format!(
1487 type_offset.to_string(&context.config),
1490 _ => Some(prefix + &ty),
1493 let ty = try_opt!(rewrite_type_in_next_line());
1497 type_offset.to_string(&context.config),
1504 pub fn rewrite_static(
1506 vis: &ast::Visibility,
1509 mutability: ast::Mutability,
1510 expr_opt: Option<&ptr::P<ast::Expr>>,
1513 context: &RewriteContext,
1514 ) -> Option<String> {
1515 let colon = colon_spaces(
1516 context.config.space_before_type_annotation(),
1517 context.config.space_after_type_annotation_colon(),
1519 let prefix = format!(
1521 format_visibility(vis),
1523 format_mutability(mutability),
1528 let ty_str = try_opt!(ty.rewrite(
1531 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)
1535 if let Some(expr) = expr_opt {
1536 let lhs = format!("{}{} =", prefix, ty_str);
1538 let remaining_width = context.config.max_width() - offset.block_indent - 1;
1543 Shape::legacy(remaining_width, offset.block_only()),
1545 recover_comment_removed(res, span, context, Shape::indented(offset, context.config))
1547 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1549 Some(format!("{}{};", prefix, ty_str))
1553 pub fn rewrite_associated_type(
1555 ty_opt: Option<&ptr::P<ast::Ty>>,
1556 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1557 context: &RewriteContext,
1559 ) -> Option<String> {
1560 let prefix = format!("type {}", ident);
1562 let type_bounds_str = if let Some(ty_param_bounds) = ty_param_bounds_opt {
1563 let shape = Shape::indented(indent, context.config);
1564 let bounds: &[_] = ty_param_bounds;
1565 let bound_str = try_opt!(
1568 .map(|ty_bound| ty_bound.rewrite(context, shape))
1569 .collect::<Option<Vec<_>>>()
1571 if bounds.len() > 0 {
1572 format!(": {}", join_bounds(context, shape, &bound_str))
1580 if let Some(ty) = ty_opt {
1581 let ty_str = try_opt!(ty.rewrite(
1584 context.config.max_width() - indent.block_indent - prefix.len() - 2,
1585 indent.block_only(),
1588 Some(format!("{} = {};", prefix, ty_str))
1590 Some(format!("{}{};", prefix, type_bounds_str))
1594 pub fn rewrite_associated_impl_type(
1596 defaultness: ast::Defaultness,
1597 ty_opt: Option<&ptr::P<ast::Ty>>,
1598 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1599 context: &RewriteContext,
1601 ) -> Option<String> {
1602 let result = try_opt!(rewrite_associated_type(
1605 ty_param_bounds_opt,
1611 ast::Defaultness::Default => Some(format!("default {}", result)),
1616 impl Rewrite for ast::FunctionRetTy {
1617 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1619 ast::FunctionRetTy::Default(_) => Some(String::new()),
1620 ast::FunctionRetTy::Ty(ref ty) => {
1621 let inner_width = try_opt!(shape.width.checked_sub(3));
1622 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1623 .map(|r| format!("-> {}", r))
1629 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1631 ast::TyKind::Infer => {
1632 let original = context.snippet(ty.span);
1639 impl Rewrite for ast::Arg {
1640 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1641 if is_named_arg(self) {
1642 let mut result = try_opt!(
1644 .rewrite(context, Shape::legacy(shape.width, shape.indent))
1647 if !is_empty_infer(context, &*self.ty) {
1648 if context.config.space_before_type_annotation() {
1649 result.push_str(" ");
1651 result.push_str(":");
1652 if context.config.space_after_type_annotation_colon() {
1653 result.push_str(" ");
1655 let max_width = try_opt!(shape.width.checked_sub(result.len()));
1656 let ty_str = try_opt!(self.ty.rewrite(
1658 Shape::legacy(max_width, shape.indent + result.len()),
1660 result.push_str(&ty_str);
1665 self.ty.rewrite(context, shape)
1670 fn rewrite_explicit_self(
1671 explicit_self: &ast::ExplicitSelf,
1673 context: &RewriteContext,
1674 ) -> Option<String> {
1675 match explicit_self.node {
1676 ast::SelfKind::Region(lt, m) => {
1677 let mut_str = format_mutability(m);
1680 let lifetime_str = try_opt!(l.rewrite(
1682 Shape::legacy(context.config.max_width(), Indent::empty()),
1684 Some(format!("&{} {}self", lifetime_str, mut_str))
1686 None => Some(format!("&{}self", mut_str)),
1689 ast::SelfKind::Explicit(ref ty, _) => {
1690 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1692 let mutability = explicit_self_mutability(&args[0]);
1693 let type_str = try_opt!(ty.rewrite(
1695 Shape::legacy(context.config.max_width(), Indent::empty()),
1700 format_mutability(mutability),
1704 ast::SelfKind::Value(_) => {
1705 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1707 let mutability = explicit_self_mutability(&args[0]);
1709 Some(format!("{}self", format_mutability(mutability)))
1714 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1715 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1716 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1717 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1724 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1725 if is_named_arg(arg) {
1732 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1734 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi,
1735 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi,
1736 _ => arg.ty.span.hi,
1740 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1741 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1742 ident.node != symbol::keywords::Invalid.ident()
1748 // Return type is (result, force_new_line_for_brace)
1750 context: &RewriteContext,
1754 generics: &ast::Generics,
1755 unsafety: ast::Unsafety,
1756 constness: ast::Constness,
1757 defaultness: ast::Defaultness,
1759 vis: &ast::Visibility,
1761 newline_brace: bool,
1764 ) -> Option<(String, bool)> {
1765 let mut force_new_line_for_brace = false;
1767 let where_clause = &generics.where_clause;
1769 let mut result = String::with_capacity(1024);
1770 // Vis unsafety abi.
1771 result.push_str(&*format_visibility(vis));
1773 if let ast::Defaultness::Default = defaultness {
1774 result.push_str("default ");
1777 if let ast::Constness::Const = constness {
1778 result.push_str("const ");
1781 result.push_str(::utils::format_unsafety(unsafety));
1783 if abi != abi::Abi::Rust {
1784 result.push_str(&::utils::format_abi(
1786 context.config.force_explicit_abi(),
1791 result.push_str("fn ");
1792 result.push_str(&ident.to_string());
1795 let overhead = if has_braces && !newline_brace {
1802 let shape = try_opt!(
1803 Shape::indented(indent + last_line_width(&result), context.config).sub_width(overhead)
1805 let g_span = mk_sp(span.lo, fd.output.span().lo);
1806 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1807 result.push_str(&generics_str);
1809 let snuggle_angle_bracket = generics_str
1812 .map_or(false, |l| l.trim_left().len() == 1);
1814 // Note that the width and indent don't really matter, we'll re-layout the
1815 // return type later anyway.
1816 let ret_str = try_opt!(
1818 .rewrite(&context, Shape::indented(indent, context.config))
1821 let multi_line_ret_str = ret_str.contains('\n');
1822 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1825 let (mut one_line_budget, mut multi_line_budget, mut arg_indent) =
1826 try_opt!(compute_budgets_for_args(
1835 if context.config.fn_args_layout() == IndentStyle::Block {
1836 arg_indent = indent.block_indent(context.config);
1838 multi_line_budget = context.config.max_width() - (arg_indent.width() + 1);
1842 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1848 // Check if vertical layout was forced.
1849 if one_line_budget == 0 {
1850 if snuggle_angle_bracket {
1853 if context.config.fn_args_paren_newline() {
1855 result.push_str(&arg_indent.to_string(context.config));
1856 if context.config.fn_args_layout() == IndentStyle::Visual {
1857 arg_indent = arg_indent + 1; // extra space for `(`
1861 result.push_str("(");
1862 if context.config.fn_args_layout() == IndentStyle::Visual {
1864 result.push_str(&arg_indent.to_string(context.config));
1871 if context.config.spaces_within_parens() && fd.inputs.len() > 0 && result.ends_with('(') {
1875 if multi_line_ret_str {
1876 one_line_budget = 0;
1879 // A conservative estimation, to goal is to be over all parens in generics
1880 let args_start = generics
1883 .map_or(span.lo, |tp| end_typaram(tp));
1884 let args_end = if fd.inputs.is_empty() {
1885 context.codemap.span_after(mk_sp(args_start, span.hi), ")")
1887 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi, span.hi);
1888 context.codemap.span_after(last_span, ")")
1890 let args_span = mk_sp(
1891 context.codemap.span_after(mk_sp(args_start, span.hi), "("),
1894 let arg_str = try_opt!(rewrite_args(
1897 fd.get_self().as_ref(),
1904 generics_str.contains('\n'),
1907 let multi_line_arg_str =
1908 arg_str.contains('\n') || arg_str.chars().last().map_or(false, |c| c == ',');
1910 let put_args_in_block = match context.config.fn_args_layout() {
1911 IndentStyle::Block => multi_line_arg_str || generics_str.contains('\n'),
1913 } && !fd.inputs.is_empty();
1915 let mut args_last_line_contains_comment = false;
1916 if put_args_in_block {
1917 arg_indent = indent.block_indent(context.config);
1919 result.push_str(&arg_indent.to_string(context.config));
1920 result.push_str(&arg_str);
1922 result.push_str(&indent.to_string(context.config));
1925 result.push_str(&arg_str);
1926 if context.config.spaces_within_parens() && fd.inputs.len() > 0 {
1929 // If the last line of args contains comment, we cannot put the closing paren
1930 // on the same line.
1934 .map_or(false, |last_line| last_line.contains("//"))
1936 args_last_line_contains_comment = true;
1938 result.push_str(&arg_indent.to_string(context.config));
1944 if !ret_str.is_empty() {
1945 let ret_should_indent = match context.config.fn_args_layout() {
1946 // If our args are block layout then we surely must have space.
1947 IndentStyle::Block if put_args_in_block => false,
1949 // If we've already gone multi-line, or the return type would push over the max
1950 // width, then put the return type on a new line. With the +1 for the signature
1951 // length an additional space between the closing parenthesis of the argument and
1952 // the arrow '->' is considered.
1953 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1955 // If there is no where clause, take into account the space after the return type
1957 if where_clause.predicates.is_empty() {
1961 let overlong_sig = sig_length > context.config.max_width();
1963 (!args_last_line_contains_comment) &&
1964 (result.contains('\n') || multi_line_ret_str || overlong_sig)
1967 let ret_indent = if ret_should_indent {
1968 let indent = match context.config.fn_return_indent() {
1969 ReturnIndent::WithWhereClause => indent + 4,
1970 // Aligning with non-existent args looks silly.
1971 _ if arg_str.is_empty() => {
1972 force_new_line_for_brace = true;
1975 // FIXME: we might want to check that using the arg indent
1976 // doesn't blow our budget, and if it does, then fallback to
1977 // the where clause indent.
1982 result.push_str(&indent.to_string(context.config));
1986 Indent::new(indent.block_indent, last_line_width(&result))
1989 if multi_line_ret_str || ret_should_indent {
1990 // Now that we know the proper indent and width, we need to
1991 // re-layout the return type.
1992 let ret_str = try_opt!(
1994 .rewrite(context, Shape::indented(ret_indent, context.config))
1996 result.push_str(&ret_str);
1998 result.push_str(&ret_str);
2001 // Comment between return type and the end of the decl.
2002 let snippet_lo = fd.output.span().hi;
2003 if where_clause.predicates.is_empty() {
2004 let snippet_hi = span.hi;
2005 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2006 // Try to preserve the layout of the original snippet.
2007 let original_starts_with_newline = snippet
2009 .map_or(false, |i| snippet[i..].starts_with('\n'));
2010 let original_ends_with_newline = snippet
2011 .rfind(|c| c != ' ')
2012 .map_or(false, |i| snippet[i..].ends_with('\n'));
2013 let snippet = snippet.trim();
2014 if !snippet.is_empty() {
2015 result.push(if original_starts_with_newline {
2020 result.push_str(snippet);
2021 if original_ends_with_newline {
2022 force_new_line_for_brace = true;
2026 // FIXME it would be nice to catch comments between the return type
2027 // and the where clause, but we don't have a span for the where
2032 let should_compress_where = match context.config.where_density() {
2033 Density::Compressed => !result.contains('\n') || put_args_in_block,
2034 Density::CompressedIfEmpty => !has_body && !result.contains('\n'),
2036 } || (put_args_in_block && ret_str.is_empty());
2038 let pos_before_where = match fd.output {
2039 ast::FunctionRetTy::Default(..) => args_span.hi,
2040 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi,
2042 if where_clause.predicates.len() == 1 && should_compress_where {
2043 let budget = try_opt!(
2047 .checked_sub(last_line_width(&result))
2049 if let Some(where_clause_str) = rewrite_where_clause(
2052 context.config.fn_brace_style(),
2053 Shape::legacy(budget, indent),
2054 Density::Compressed,
2057 put_args_in_block && ret_str.is_empty(),
2062 if !where_clause_str.contains('\n') {
2063 if last_line_width(&result) + where_clause_str.len() > context.config.max_width() {
2067 result.push_str(&where_clause_str);
2069 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2070 return Some((result, force_new_line_for_brace));
2075 let where_clause_str = try_opt!(rewrite_where_clause(
2078 context.config.fn_brace_style(),
2079 Shape::indented(indent, context.config),
2083 put_args_in_block && ret_str.is_empty(),
2089 result.push_str(&where_clause_str);
2091 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2092 return Some((result, force_new_line_for_brace));
2095 fn last_line_contains_single_line_comment(s: &str) -> bool {
2096 s.lines().last().map_or(false, |l| l.contains("//"))
2100 context: &RewriteContext,
2102 explicit_self: Option<&ast::ExplicitSelf>,
2103 one_line_budget: usize,
2104 multi_line_budget: usize,
2109 generics_str_contains_newline: bool,
2110 ) -> Option<String> {
2111 let mut arg_item_strs = try_opt!(
2114 arg.rewrite(&context, Shape::legacy(multi_line_budget, arg_indent))
2116 .collect::<Option<Vec<_>>>()
2119 // Account for sugary self.
2120 // FIXME: the comment for the self argument is dropped. This is blocked
2121 // on rust issue #27522.
2122 let min_args = explicit_self
2123 .and_then(|explicit_self| {
2124 rewrite_explicit_self(explicit_self, args, context)
2126 .map_or(1, |self_str| {
2127 arg_item_strs[0] = self_str;
2131 // Comments between args.
2132 let mut arg_items = Vec::new();
2134 arg_items.push(ListItem::from_str(""));
2137 // FIXME(#21): if there are no args, there might still be a comment, but
2138 // without spans for the comment or parens, there is no chance of
2139 // getting it right. You also don't get to put a comment on self, unless
2141 if args.len() >= min_args || variadic {
2142 let comment_span_start = if min_args == 2 {
2143 let second_arg_start = if arg_has_pattern(&args[1]) {
2148 let reduced_span = mk_sp(span.lo, second_arg_start);
2150 context.codemap.span_after_last(reduced_span, ",")
2155 enum ArgumentKind<'a> {
2156 Regular(&'a ast::Arg),
2160 let variadic_arg = if variadic {
2161 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi, span.hi);
2162 let variadic_start = context.codemap.span_after(variadic_span, "...") - BytePos(3);
2163 Some(ArgumentKind::Variadic(variadic_start))
2168 let more_items = itemize_list(
2170 args[min_args - 1..]
2172 .map(ArgumentKind::Regular)
2173 .chain(variadic_arg),
2176 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2177 ArgumentKind::Variadic(start) => start,
2180 ArgumentKind::Regular(arg) => arg.ty.span.hi,
2181 ArgumentKind::Variadic(start) => start + BytePos(3),
2184 ArgumentKind::Regular(..) => None,
2185 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2191 arg_items.extend(more_items);
2194 let fits_in_one_line = !generics_str_contains_newline &&
2195 (arg_items.len() == 0 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2197 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2198 item.item = Some(arg);
2201 let last_line_ends_with_comment = arg_items
2204 .and_then(|item| item.post_comment.as_ref())
2205 .map_or(false, |s| s.trim().starts_with("//"));
2207 let (indent, trailing_comma) = match context.config.fn_args_layout() {
2208 IndentStyle::Block if fits_in_one_line => {
2209 (indent.block_indent(context.config), SeparatorTactic::Never)
2211 IndentStyle::Block => (
2212 indent.block_indent(context.config),
2213 context.config.trailing_comma(),
2215 IndentStyle::Visual if last_line_ends_with_comment => {
2216 (arg_indent, context.config.trailing_comma())
2218 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2221 let tactic = definitive_tactic(
2223 context.config.fn_args_density().to_list_tactic(),
2226 let budget = match tactic {
2227 DefinitiveListTactic::Horizontal => one_line_budget,
2228 _ => multi_line_budget,
2231 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2233 let fmt = ListFormatting {
2236 trailing_separator: if variadic {
2237 SeparatorTactic::Never
2241 shape: Shape::legacy(budget, indent),
2242 ends_with_newline: tactic.ends_with_newline(context.config.fn_args_layout()),
2243 config: context.config,
2246 write_list(&arg_items, &fmt)
2249 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2250 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2251 ident.node != symbol::keywords::Invalid.ident()
2257 fn compute_budgets_for_args(
2258 context: &RewriteContext,
2262 newline_brace: bool,
2264 ) -> Option<((usize, usize, Indent))> {
2266 "compute_budgets_for_args {} {:?}, {}, {}",
2272 // Try keeping everything on the same line.
2273 if !result.contains('\n') {
2274 // 2 = `()`, 3 = `() `, space is before ret_string.
2275 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2276 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2286 let one_line_budget = context
2289 .checked_sub(used_space)
2292 if one_line_budget > 0 {
2294 let multi_line_overhead =
2295 indent.width() + result.len() + if newline_brace { 2 } else { 4 };
2296 let multi_line_budget =
2297 try_opt!(context.config.max_width().checked_sub(multi_line_overhead));
2302 indent + result.len() + 1,
2307 // Didn't work. we must force vertical layout and put args on a newline.
2308 let new_indent = indent.block_indent(context.config);
2309 // Account for `)` and possibly ` {`.
2310 let used_space = new_indent.width() + if ret_str_len == 0 { 1 } else { 3 };
2311 let max_space = try_opt!(context.config.max_width().checked_sub(used_space));
2312 Some((0, max_space, new_indent))
2315 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2316 match config.fn_brace_style() {
2317 BraceStyle::AlwaysNextLine => true,
2318 BraceStyle::SameLineWhere if !where_clause.predicates.is_empty() => true,
2323 fn rewrite_generics(
2324 context: &RewriteContext,
2325 generics: &ast::Generics,
2328 ) -> Option<String> {
2329 let g_shape = try_opt!(generics_shape_from_config(context.config, shape, 0));
2330 let one_line_width = shape.width.checked_sub(2).unwrap_or(0);
2331 rewrite_generics_inner(context, generics, g_shape, one_line_width, span).or_else(|| {
2332 rewrite_generics_inner(context, generics, g_shape, 0, span)
2336 fn rewrite_generics_inner(
2337 context: &RewriteContext,
2338 generics: &ast::Generics,
2340 one_line_width: usize,
2342 ) -> Option<String> {
2343 // FIXME: convert bounds to where clauses where they get too big or if
2344 // there is a where clause at all.
2345 let lifetimes: &[_] = &generics.lifetimes;
2346 let tys: &[_] = &generics.ty_params;
2347 if lifetimes.is_empty() && tys.is_empty() {
2348 return Some(String::new());
2351 // Strings for the generics.
2352 let lt_strs = lifetimes.iter().map(|lt| lt.rewrite(context, shape));
2353 let ty_strs = tys.iter().map(|ty_param| ty_param.rewrite(context, shape));
2355 // Extract comments between generics.
2356 let lt_spans = lifetimes.iter().map(|l| {
2357 let hi = if l.bounds.is_empty() {
2360 l.bounds[l.bounds.len() - 1].span.hi
2362 mk_sp(l.lifetime.span.lo, hi)
2364 let ty_spans = tys.iter().map(|ty| ty.span());
2366 let items = itemize_list(
2368 lt_spans.chain(ty_spans).zip(lt_strs.chain(ty_strs)),
2372 // FIXME: don't clone
2373 |&(_, ref str)| str.clone(),
2374 context.codemap.span_after(span, "<"),
2377 format_generics_item_list(context, items, shape, one_line_width)
2380 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2381 match config.generics_indent() {
2382 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2383 IndentStyle::Block => {
2387 .block_indent(config.tab_spaces())
2388 .with_max_width(config)
2394 pub fn format_generics_item_list<I>(
2395 context: &RewriteContext,
2398 one_line_budget: usize,
2401 I: Iterator<Item = ListItem>,
2403 let item_vec = items.collect::<Vec<_>>();
2405 let tactic = definitive_tactic(&item_vec, ListTactic::HorizontalVertical, one_line_budget);
2406 let fmt = ListFormatting {
2409 trailing_separator: if context.config.generics_indent() == IndentStyle::Visual {
2410 SeparatorTactic::Never
2412 context.config.trailing_comma()
2415 ends_with_newline: tactic.ends_with_newline(context.config.generics_indent()),
2416 config: context.config,
2419 let list_str = try_opt!(write_list(&item_vec, &fmt));
2421 Some(wrap_generics_with_angle_brackets(
2428 pub fn wrap_generics_with_angle_brackets(
2429 context: &RewriteContext,
2431 list_offset: Indent,
2433 if context.config.generics_indent() == IndentStyle::Block &&
2434 (list_str.contains('\n') || list_str.ends_with(','))
2438 list_offset.to_string(context.config),
2441 .block_unindent(context.config)
2442 .to_string(context.config)
2444 } else if context.config.spaces_within_angle_brackets() {
2445 format!("< {} >", list_str)
2447 format!("<{}>", list_str)
2451 fn rewrite_trait_bounds(
2452 context: &RewriteContext,
2453 type_param_bounds: &ast::TyParamBounds,
2455 ) -> Option<String> {
2456 let bounds: &[_] = type_param_bounds;
2458 if bounds.is_empty() {
2459 return Some(String::new());
2461 let bound_str = try_opt!(
2464 .map(|ty_bound| ty_bound.rewrite(&context, shape))
2465 .collect::<Option<Vec<_>>>()
2467 Some(format!(": {}", join_bounds(context, shape, &bound_str)))
2470 fn rewrite_where_clause_rfc_style(
2471 context: &RewriteContext,
2472 where_clause: &ast::WhereClause,
2475 suppress_comma: bool,
2476 // where clause can be kept on the current line.
2478 span_end: Option<BytePos>,
2480 span_end_before_where: BytePos,
2481 ) -> Option<String> {
2482 let block_shape = shape.block().with_max_width(context.config);
2484 let (span_before, span_after) =
2485 missing_span_before_after_where(context, span.hi, span_end_before_where, where_clause);
2486 let (comment_before, comment_after) = try_opt!(rewrite_comments_before_after_where(
2493 let starting_newline = if snuggle && comment_before.is_empty() {
2496 "\n".to_owned() + &block_shape.indent.to_string(context.config)
2499 let clause_shape = block_shape.block_indent(context.config.tab_spaces());
2500 // each clause on one line, trailing comma (except if suppress_comma)
2501 let span_start = where_clause.predicates[0].span().lo;
2502 // If we don't have the start of the next span, then use the end of the
2503 // predicates, but that means we miss comments.
2504 let len = where_clause.predicates.len();
2505 let end_of_preds = where_clause.predicates[len - 1].span().hi;
2506 let span_end = span_end.unwrap_or(end_of_preds);
2507 let items = itemize_list(
2509 where_clause.predicates.iter(),
2511 |pred| pred.span().lo,
2512 |pred| pred.span().hi,
2513 |pred| pred.rewrite(context, block_shape),
2517 let comma_tactic = if suppress_comma {
2518 SeparatorTactic::Never
2520 context.config.trailing_comma()
2523 let fmt = ListFormatting {
2524 tactic: DefinitiveListTactic::Vertical,
2526 trailing_separator: comma_tactic,
2527 shape: clause_shape,
2528 ends_with_newline: true,
2529 config: context.config,
2531 let preds_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
2533 let newline_before_where = if comment_before.is_empty() || comment_before.ends_with('\n') {
2536 "\n".to_owned() + &shape.indent.to_string(context.config)
2538 let newline_after_where = if comment_after.is_empty() {
2541 "\n".to_owned() + &clause_shape.indent.to_string(context.config)
2544 "{}{}{}where{}{}\n{}{}",
2547 newline_before_where,
2548 newline_after_where,
2550 clause_shape.indent.to_string(context.config),
2555 fn rewrite_where_clause(
2556 context: &RewriteContext,
2557 where_clause: &ast::WhereClause,
2558 brace_style: BraceStyle,
2562 suppress_comma: bool,
2564 span_end: Option<BytePos>,
2566 span_end_before_where: BytePos,
2567 ) -> Option<String> {
2568 if where_clause.predicates.is_empty() {
2569 return Some(String::new());
2572 if context.config.where_style() == Style::Rfc {
2573 return rewrite_where_clause_rfc_style(
2582 span_end_before_where,
2586 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2588 let offset = match context.config.where_pred_indent() {
2589 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2590 // 6 = "where ".len()
2591 IndentStyle::Visual => shape.indent + extra_indent + 6,
2593 // FIXME: if where_pred_indent != Visual, then the budgets below might
2594 // be out by a char or two.
2596 let budget = context.config.max_width() - offset.width();
2597 let span_start = where_clause.predicates[0].span().lo;
2598 // If we don't have the start of the next span, then use the end of the
2599 // predicates, but that means we miss comments.
2600 let len = where_clause.predicates.len();
2601 let end_of_preds = where_clause.predicates[len - 1].span().hi;
2602 let span_end = span_end.unwrap_or(end_of_preds);
2603 let items = itemize_list(
2605 where_clause.predicates.iter(),
2607 |pred| pred.span().lo,
2608 |pred| pred.span().hi,
2609 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2613 let item_vec = items.collect::<Vec<_>>();
2614 // FIXME: we don't need to collect here if the where_layout isn't
2615 // HorizontalVertical.
2616 let tactic = definitive_tactic(&item_vec, context.config.where_layout(), budget);
2618 let mut comma_tactic = context.config.trailing_comma();
2619 // Kind of a hack because we don't usually have trailing commas in where clauses.
2620 if comma_tactic == SeparatorTactic::Vertical || suppress_comma {
2621 comma_tactic = SeparatorTactic::Never;
2624 let fmt = ListFormatting {
2627 trailing_separator: comma_tactic,
2628 shape: Shape::legacy(budget, offset),
2629 ends_with_newline: tactic.ends_with_newline(context.config.where_pred_indent()),
2630 config: context.config,
2632 let preds_str = try_opt!(write_list(&item_vec, &fmt));
2634 let end_length = if terminator == "{" {
2635 // If the brace is on the next line we don't need to count it otherwise it needs two
2638 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2639 BraceStyle::PreferSameLine => 2,
2641 } else if terminator == "=" {
2646 if density == Density::Tall || preds_str.contains('\n') ||
2647 shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2651 (shape.indent + extra_indent).to_string(context.config),
2655 Some(format!(" where {}", preds_str))
2659 fn missing_span_before_after_where(
2660 context: &RewriteContext,
2662 before_item_span_end: BytePos,
2663 where_clause: &ast::WhereClause,
2665 let snippet = context.snippet(mk_sp(before_item_span_end, item_end));
2666 let pos_before_where =
2667 before_item_span_end + BytePos(snippet.find_uncommented("where").unwrap() as u32);
2668 let missing_span_before = mk_sp(before_item_span_end, pos_before_where);
2670 let pos_after_where = pos_before_where + BytePos(5);
2671 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo);
2672 (missing_span_before, missing_span_after)
2675 fn rewrite_missing_comment_in_where(
2676 context: &RewriteContext,
2679 ) -> Option<String> {
2680 let comment = comment.trim();
2681 if comment.is_empty() {
2684 rewrite_comment(comment, false, shape, context.config)
2688 fn rewrite_comments_before_after_where(
2689 context: &RewriteContext,
2690 span_before_where: Span,
2691 span_after_where: Span,
2693 ) -> Option<(String, String)> {
2694 let before_comment = try_opt!(rewrite_missing_comment_in_where(
2696 &context.snippet(span_before_where),
2699 let after_comment = try_opt!(rewrite_missing_comment_in_where(
2701 &context.snippet(span_after_where),
2702 shape.block_indent(context.config.tab_spaces()),
2704 Some((before_comment, after_comment))
2707 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2708 format!("{}{}{}", format_visibility(vis), item_name, ident)
2712 context: &RewriteContext,
2713 generics: &ast::Generics,
2716 brace_style: BraceStyle,
2717 force_same_line_brace: bool,
2721 ) -> Option<String> {
2722 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2723 let mut result = try_opt!(rewrite_generics(context, generics, shape, span));
2725 if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2726 let budget = try_opt!(
2730 .checked_sub(last_line_width(&result))
2732 let where_clause_str = try_opt!(rewrite_where_clause(
2734 &generics.where_clause,
2736 Shape::legacy(budget, offset.block_only()),
2740 trimmed_last_line_width(&result) == 1,
2745 result.push_str(&where_clause_str);
2746 let same_line_brace = force_same_line_brace ||
2747 (generics.where_clause.predicates.is_empty() && trimmed_last_line_width(&result) == 1);
2748 if !same_line_brace &&
2749 (brace_style == BraceStyle::SameLineWhere ||
2750 brace_style == BraceStyle::AlwaysNextLine)
2753 result.push_str(&offset.block_only().to_string(context.config));
2757 result.push_str(opener);
2759 if force_same_line_brace || trimmed_last_line_width(&result) == 1 ||
2760 brace_style != BraceStyle::AlwaysNextLine
2765 result.push_str(&offset.block_only().to_string(context.config));
2767 result.push_str(opener);