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 {Indent, Shape, Spanned};
14 use codemap::SpanUtils;
15 use utils::{format_mutability, format_visibility, contains_skip, end_typaram, wrap_str,
16 last_line_width, format_unsafety, trim_newlines, stmt_expr, semicolon_for_expr,
17 trimmed_last_line_width, colon_spaces, mk_sp};
18 use lists::{write_list, itemize_list, ListItem, ListFormatting, SeparatorTactic,
19 DefinitiveListTactic, ListTactic, definitive_tactic};
20 use expr::{format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs,
21 rewrite_call_inner, ExprType};
22 use comment::{FindUncommented, contains_comment, rewrite_comment, recover_comment_removed};
23 use visitor::FmtVisitor;
24 use rewrite::{Rewrite, RewriteContext};
25 use config::{Config, IndentStyle, Density, ReturnIndent, BraceStyle, Style};
26 use types::join_bounds;
27 use vertical::rewrite_with_alignment;
29 use syntax::{ast, abi, ptr, symbol};
30 use syntax::codemap::{Span, BytePos};
31 use syntax::ast::ImplItem;
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(e) { ";" } else { "" };
361 Shape::indented(self.block_indent, self.config),
362 ).map(|s| s + suffix)
363 .or_else(|| Some(self.snippet(e.span)))
368 Shape::indented(self.block_indent, self.config),
377 if let Some(res) = rewrite {
378 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
379 if !res.contains('\n') && width <= self.config.max_width() {
380 return Some(format!("{}{{ {} }}", fn_str, res));
391 vis: &ast::Visibility,
392 enum_def: &ast::EnumDef,
393 generics: &ast::Generics,
396 let enum_header = format_header("enum ", ident, vis);
397 self.buffer.push_str(&enum_header);
399 let enum_snippet = self.snippet(span);
400 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
401 let body_start = span.lo + BytePos(brace_pos as u32 + 1);
402 let generics_str = format_generics(
407 self.config.item_brace_style(),
408 enum_def.variants.is_empty(),
410 mk_sp(span.lo, body_start),
411 last_line_width(&enum_header),
413 self.buffer.push_str(&generics_str);
415 self.last_pos = body_start;
417 self.block_indent = self.block_indent.block_indent(self.config);
418 let variant_list = self.format_variant_list(enum_def, body_start, span.hi - BytePos(1));
420 Some(ref body_str) => self.buffer.push_str(body_str),
422 if contains_comment(&enum_snippet[brace_pos..]) {
423 self.format_missing_no_indent(span.hi - BytePos(1))
425 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 => {
624 if !where_clause_str.is_empty() {
626 result.push_str(&offset.to_string(context.config));
635 let snippet = context.snippet(item.span);
636 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
638 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
639 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
640 visitor.block_indent = offset.block_only().block_indent(context.config);
641 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
644 visitor.visit_impl_item(item);
647 visitor.format_missing(item.span.hi - BytePos(1));
649 let inner_indent_str = visitor.block_indent.to_string(context.config);
650 let outer_indent_str = offset.block_only().to_string(context.config);
653 result.push_str(&inner_indent_str);
654 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
656 result.push_str(&outer_indent_str);
659 if result.chars().last().unwrap() == '{' {
661 result.push_str(&offset.to_string(context.config));
671 fn is_impl_single_line(
672 context: &RewriteContext,
675 where_clause_str: &str,
678 let snippet = context.snippet(item.span);
679 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
682 context.config.impl_empty_single_line() && items.is_empty() &&
683 result.len() + where_clause_str.len() <= context.config.max_width() &&
684 !contains_comment(&snippet[open_pos..]),
688 fn format_impl_ref_and_type(
689 context: &RewriteContext,
692 ) -> Option<String> {
693 if let ast::ItemKind::Impl(
703 let mut result = String::new();
705 result.push_str(&format_visibility(&item.vis));
706 result.push_str(format_unsafety(unsafety));
707 result.push_str("impl");
709 let lo = context.codemap.span_after(item.span, "impl");
710 let hi = match *trait_ref {
711 Some(ref tr) => tr.path.span.lo,
712 None => self_ty.span.lo,
714 let shape = try_opt!(generics_shape_from_config(
716 Shape::indented(offset + last_line_width(&result), context.config),
719 let one_line_budget = try_opt!(shape.width.checked_sub(last_line_width(&result) + 2));
720 let generics_str = try_opt!(rewrite_generics_inner(
728 let polarity_str = if polarity == ast::ImplPolarity::Negative {
734 if let Some(ref trait_ref) = *trait_ref {
735 let result_len = result.len();
736 if let Some(trait_ref_str) = rewrite_trait_ref(
745 result.push_str(&trait_ref_str);
747 let generics_str = try_opt!(rewrite_generics_inner(
754 result.push_str(&try_opt!(rewrite_trait_ref(
765 result.push_str(&generics_str);
768 // Try to put the self type in a single line.
770 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
771 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
772 // If there is no where clause adapt budget for type formatting to take space and curly
773 // brace into account.
774 match context.config.item_brace_style() {
775 BraceStyle::AlwaysNextLine => 0,
781 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
782 // 1 = space before the type.
786 .checked_sub(used_space + 1)
788 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
789 if !self_ty_str.contains('\n') {
790 if trait_ref.is_some() {
791 result.push_str(" for ");
795 result.push_str(&self_ty_str);
800 // Couldn't fit the self type on a single line, put it on a new line.
802 // Add indentation of one additional tab.
803 let new_line_offset = offset.block_indent(context.config);
804 result.push_str(&new_line_offset.to_string(context.config));
805 if trait_ref.is_some() {
806 result.push_str("for ");
808 let budget = context.config.max_width() - last_line_width(&result);
809 let type_offset = match context.config.where_style() {
810 Style::Legacy => new_line_offset + trait_ref_overhead,
811 Style::Rfc => new_line_offset,
813 result.push_str(&*try_opt!(
814 self_ty.rewrite(context, Shape::legacy(budget, type_offset))
822 fn rewrite_trait_ref(
823 context: &RewriteContext,
824 trait_ref: &ast::TraitRef,
830 ) -> Option<String> {
831 // 1 = space between generics and trait_ref
832 let used_space = 1 + polarity_str.len() +
833 if generics_str.contains('\n') {
834 last_line_width(&generics_str)
836 result_len + generics_str.len()
838 let shape = Shape::indented(offset + used_space, context.config);
839 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
840 if !(retry && trait_ref_str.contains('\n')) {
849 // We could not make enough space for trait_ref, so put it on new line.
851 let offset = offset.block_indent(context.config);
852 let shape = Shape::indented(offset, context.config);
853 let trait_ref_str = try_opt!(trait_ref.rewrite(context, shape));
857 &offset.to_string(context.config),
866 pub fn format_struct(
867 context: &RewriteContext,
870 vis: &ast::Visibility,
871 struct_def: &ast::VariantData,
872 generics: Option<&ast::Generics>,
875 one_line_width: Option<usize>,
876 ) -> Option<String> {
878 ast::VariantData::Unit(..) => Some(format_unit_struct(item_name, ident, vis)),
879 ast::VariantData::Tuple(ref fields, _) => {
891 ast::VariantData::Struct(ref fields, _) => {
892 format_struct_struct(
907 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
908 if let ast::ItemKind::Trait(unsafety, ref generics, ref type_param_bounds, ref trait_items) =
911 let mut result = String::new();
912 let header = format!(
914 format_visibility(&item.vis),
915 format_unsafety(unsafety),
919 result.push_str(&header);
921 let body_lo = context.codemap.span_after(item.span, "{");
923 let shape = Shape::indented(offset + last_line_width(&result), context.config);
924 let generics_str = try_opt!(rewrite_generics(
928 mk_sp(item.span.lo, body_lo),
930 result.push_str(&generics_str);
932 let trait_bound_str = try_opt!(rewrite_trait_bounds(
935 Shape::indented(offset, context.config),
937 // If the trait, generics, and trait bound cannot fit on the same line,
938 // put the trait bounds on an indented new line
939 if offset.width() + last_line_width(&result) + trait_bound_str.len() >
940 context.config.comment_width()
943 let trait_indent = offset.block_only().block_indent(context.config);
944 result.push_str(&trait_indent.to_string(context.config));
946 result.push_str(&trait_bound_str);
948 let has_body = !trait_items.is_empty();
950 let where_density = if (context.config.where_density() == Density::Compressed &&
951 (!result.contains('\n') ||
952 context.config.fn_args_layout() == IndentStyle::Block)) ||
953 (context.config.fn_args_layout() == IndentStyle::Block && result.is_empty()) ||
954 (context.config.where_density() == Density::CompressedIfEmpty && !has_body &&
955 !result.contains('\n'))
962 let where_budget = try_opt!(
966 .checked_sub(last_line_width(&result))
968 let pos_before_where = if type_param_bounds.is_empty() {
969 // We do not use this, so it does not matter
972 type_param_bounds[type_param_bounds.len() - 1].span().hi
974 let where_clause_str = try_opt!(rewrite_where_clause(
976 &generics.where_clause,
977 context.config.item_brace_style(),
978 Shape::legacy(where_budget, offset.block_only()),
982 trait_bound_str.is_empty() && last_line_width(&generics_str) == 1,
987 // If the where clause cannot fit on the same line,
988 // put the where clause on a new line
989 if !where_clause_str.contains('\n') &&
990 last_line_width(&result) + where_clause_str.len() + offset.width() >
991 context.config.comment_width()
994 let width = offset.block_indent + context.config.tab_spaces() - 1;
995 let where_indent = Indent::new(0, width);
996 result.push_str(&where_indent.to_string(context.config));
998 result.push_str(&where_clause_str);
1000 match context.config.item_brace_style() {
1001 BraceStyle::AlwaysNextLine => {
1003 result.push_str(&offset.to_string(context.config));
1005 BraceStyle::PreferSameLine => result.push(' '),
1006 BraceStyle::SameLineWhere => {
1007 if !where_clause_str.is_empty() &&
1008 (!trait_items.is_empty() || result.contains('\n'))
1011 result.push_str(&offset.to_string(context.config));
1019 let snippet = context.snippet(item.span);
1020 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
1022 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1023 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
1024 visitor.block_indent = offset.block_only().block_indent(context.config);
1025 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
1027 for item in trait_items {
1028 visitor.visit_trait_item(item);
1031 visitor.format_missing(item.span.hi - BytePos(1));
1033 let inner_indent_str = visitor.block_indent.to_string(context.config);
1034 let outer_indent_str = offset.block_only().to_string(context.config);
1037 result.push_str(&inner_indent_str);
1038 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
1040 result.push_str(&outer_indent_str);
1041 } else if result.contains('\n') {
1052 fn format_unit_struct(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
1053 format!("{};", format_header(item_name, ident, vis))
1056 fn format_struct_struct(
1057 context: &RewriteContext,
1060 vis: &ast::Visibility,
1061 fields: &[ast::StructField],
1062 generics: Option<&ast::Generics>,
1065 one_line_width: Option<usize>,
1066 ) -> Option<String> {
1067 let mut result = String::with_capacity(1024);
1069 let header_str = format_header(item_name, ident, vis);
1070 result.push_str(&header_str);
1072 let body_lo = context.codemap.span_after(span, "{");
1074 let generics_str = match generics {
1076 try_opt!(format_generics(
1081 context.config.item_brace_style(),
1084 mk_sp(span.lo, body_lo),
1085 last_line_width(&result),
1089 // 3 = ` {}`, 2 = ` {`.
1090 let overhead = if fields.is_empty() { 3 } else { 2 };
1091 if (context.config.item_brace_style() == BraceStyle::AlwaysNextLine &&
1092 !fields.is_empty()) ||
1096 .checked_sub(result.len())
1097 .unwrap_or(0) < overhead
1099 format!("\n{}{{", offset.block_only().to_string(context.config))
1106 let overhead = if fields.is_empty() { 1 } else { 0 };
1107 let max_len = context.config.max_width() - offset.width();
1108 if !generics_str.contains('\n') && result.len() + generics_str.len() + overhead > max_len {
1110 result.push_str(&offset
1111 .block_indent(context.config)
1112 .to_string(context.config));
1113 result.push_str(&generics_str.trim_left());
1115 result.push_str(&generics_str);
1118 if fields.is_empty() {
1119 let snippet = context.snippet(mk_sp(body_lo, span.hi - BytePos(1)));
1120 if snippet.trim().is_empty() {
1122 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1124 result.push_str(&snippet.trim_right());
1126 result.push_str(&offset.to_string(context.config));
1128 result.push_str(&snippet);
1131 return Some(result);
1134 let items_str = try_opt!(rewrite_with_alignment(
1137 Shape::indented(offset, context.config),
1138 mk_sp(body_lo, span.hi),
1139 one_line_width.unwrap_or(0),
1142 if one_line_width.is_some() && !items_str.contains('\n') {
1143 Some(format!("{} {} }}", result, items_str))
1149 .block_indent(context.config)
1150 .to_string(context.config),
1152 offset.to_string(context.config)
1157 fn format_tuple_struct(
1158 context: &RewriteContext,
1161 vis: &ast::Visibility,
1162 fields: &[ast::StructField],
1163 generics: Option<&ast::Generics>,
1166 ) -> Option<String> {
1167 let mut result = String::with_capacity(1024);
1169 let header_str = format_header(item_name, ident, vis);
1170 result.push_str(&header_str);
1172 let body_lo = if fields.is_empty() {
1173 context.codemap.span_after(span, "(")
1177 let body_hi = if fields.is_empty() {
1178 context.codemap.span_after(span, ")")
1180 // This is a dirty hack to work around a missing `)` from the span of the last field.
1181 let last_arg_span = fields[fields.len() - 1].span;
1182 if context.snippet(last_arg_span).ends_with(")") {
1187 .span_after(mk_sp(last_arg_span.hi, span.hi), ")")
1191 let where_clause_str = match generics {
1193 let budget = context.budget(last_line_width(&header_str));
1194 let shape = Shape::legacy(budget, offset);
1195 let g_span = mk_sp(span.lo, body_lo);
1196 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1197 result.push_str(&generics_str);
1199 let where_budget = context.budget(last_line_width(&result));
1200 try_opt!(rewrite_where_clause(
1202 &generics.where_clause,
1203 context.config.item_brace_style(),
1204 Shape::legacy(where_budget, offset.block_only()),
1205 Density::Compressed,
1214 None => "".to_owned(),
1217 if fields.is_empty() {
1219 let used_width = if result.contains('\n') {
1220 last_line_width(&result) + 3
1222 offset.width() + result.len() + 3
1224 if used_width > context.config.max_width() {
1226 result.push_str(&offset
1227 .block_indent(context.config)
1228 .to_string(context.config))
1231 let snippet = context.snippet(mk_sp(body_lo, context.codemap.span_before(span, ")")));
1232 if snippet.is_empty() {
1234 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1235 result.push_str(&snippet.trim_right());
1237 result.push_str(&offset.to_string(context.config));
1239 result.push_str(&snippet);
1244 let body = try_opt!(
1248 &fields.iter().map(|field| field).collect::<Vec<_>>()[..],
1250 Shape::legacy(context.budget(last_line_width(&result) + 3), offset),
1251 context.config.fn_call_width(),
1255 result.push_str(&body);
1258 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') &&
1259 (result.contains('\n') ||
1260 offset.block_indent + result.len() + where_clause_str.len() + 1 >
1261 context.config.max_width())
1263 // We need to put the where clause on a new line, but we didn't
1264 // know that earlier, so the where clause will not be indented properly.
1266 result.push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1267 .to_string(context.config));
1269 result.push_str(&where_clause_str);
1274 pub fn rewrite_type_alias(
1275 context: &RewriteContext,
1279 generics: &ast::Generics,
1280 vis: &ast::Visibility,
1282 ) -> Option<String> {
1283 let mut result = String::new();
1285 result.push_str(&format_visibility(vis));
1286 result.push_str("type ");
1287 result.push_str(&ident.to_string());
1290 let shape = try_opt!(Shape::indented(indent + result.len(), context.config).sub_width(2));
1291 let g_span = mk_sp(context.codemap.span_after(span, "type"), ty.span.lo);
1292 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1293 result.push_str(&generics_str);
1295 let where_budget = try_opt!(
1299 .checked_sub(last_line_width(&result))
1301 let where_clause_str = try_opt!(rewrite_where_clause(
1303 &generics.where_clause,
1304 context.config.item_brace_style(),
1305 Shape::legacy(where_budget, indent),
1306 context.config.where_density(),
1314 result.push_str(&where_clause_str);
1315 result.push_str(" = ");
1317 let line_width = last_line_width(&result);
1318 // This checked_sub may fail as the extra space after '=' is not taken into account
1319 // In that case the budget is set to 0 which will make ty.rewrite retry on a new line
1320 let budget = context
1323 .checked_sub(indent.width() + line_width + ";".len())
1325 let type_indent = indent + line_width;
1326 // Try to fit the type on the same line
1327 let ty_str = try_opt!(
1328 ty.rewrite(context, Shape::legacy(budget, type_indent))
1330 // The line was too short, try to put the type on the next line
1332 // Remove the space after '='
1334 let type_indent = indent.block_indent(context.config);
1336 result.push_str(&type_indent.to_string(context.config));
1337 let budget = try_opt!(
1341 .checked_sub(type_indent.width() + ";".len())
1343 ty.rewrite(context, Shape::legacy(budget, type_indent))
1346 result.push_str(&ty_str);
1347 result.push_str(";");
1351 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1353 if config.space_before_type_annotation() {
1358 if config.space_after_type_annotation_colon() {
1366 fn rewrite_missing_comment_on_field(
1367 context: &RewriteContext,
1371 result: &mut String,
1372 ) -> Option<String> {
1373 let possibly_comment_snippet = context.snippet(mk_sp(lo, hi));
1374 let newline_index = possibly_comment_snippet.find('\n');
1375 let comment_index = possibly_comment_snippet.find('/');
1376 match (newline_index, comment_index) {
1377 (Some(i), Some(j)) if i > j => result.push(' '),
1380 result.push_str(&shape.indent.to_string(context.config));
1383 let trimmed = possibly_comment_snippet.trim();
1384 if trimmed.is_empty() {
1387 rewrite_comment(trimmed, false, shape, context.config).map(|s| {
1388 format!("{}\n{}", s, shape.indent.to_string(context.config))
1393 pub fn rewrite_struct_field_prefix(
1394 context: &RewriteContext,
1395 field: &ast::StructField,
1397 ) -> Option<String> {
1398 let vis = format_visibility(&field.vis);
1399 let mut attr_str = try_opt!(
1402 .rewrite(context, Shape::indented(shape.indent, context.config))
1404 // Try format missing comments after attributes
1405 let missing_comment = if !field.attrs.is_empty() {
1406 rewrite_missing_comment_on_field(
1409 field.attrs[field.attrs.len() - 1].span.hi,
1412 ).unwrap_or(String::new())
1417 let type_annotation_spacing = type_annotation_spacing(context.config);
1418 Some(match field.ident {
1426 type_annotation_spacing.0
1429 None => format!("{}{}{}", attr_str, missing_comment, vis),
1433 fn rewrite_struct_field_type(
1434 context: &RewriteContext,
1435 last_line_width: usize,
1436 field: &ast::StructField,
1439 ) -> Option<String> {
1440 let ty_shape = try_opt!(shape.offset_left(last_line_width + spacing.len()));
1443 .rewrite(context, ty_shape)
1444 .map(|ty| format!("{}{}", spacing, ty))
1447 impl Rewrite for ast::StructField {
1448 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1449 rewrite_struct_field(context, self, shape, 0)
1453 pub fn rewrite_struct_field(
1454 context: &RewriteContext,
1455 field: &ast::StructField,
1457 lhs_max_width: usize,
1458 ) -> Option<String> {
1459 if contains_skip(&field.attrs) {
1460 let span = context.snippet(mk_sp(field.attrs[0].span.lo, field.span.hi));
1461 return wrap_str(span, context.config.max_width(), shape);
1464 let type_annotation_spacing = type_annotation_spacing(context.config);
1465 let prefix = try_opt!(rewrite_struct_field_prefix(context, field, shape));
1467 // Try to put everything on a single line.
1468 let last_line_width = last_line_width(&prefix);
1469 let mut spacing = String::from(if field.ident.is_some() {
1470 type_annotation_spacing.1
1474 let lhs_offset = lhs_max_width.checked_sub(last_line_width).unwrap_or(0);
1475 for _ in 0..lhs_offset {
1478 let ty_rewritten = rewrite_struct_field_type(context, last_line_width, field, &spacing, shape);
1479 if let Some(ref ty) = ty_rewritten {
1480 if !ty.contains('\n') {
1481 return Some(prefix + &ty);
1485 // We must use multiline.
1486 let type_offset = shape.indent.block_indent(context.config);
1487 let rewrite_type_in_next_line = || {
1490 .rewrite(context, Shape::indented(type_offset, context.config))
1493 match ty_rewritten {
1494 // If we start from the next line and type fits in a single line, then do so.
1496 match rewrite_type_in_next_line() {
1497 Some(ref new_ty) if !new_ty.contains('\n') => {
1501 type_offset.to_string(&context.config),
1505 _ => Some(prefix + &ty),
1509 let ty = try_opt!(rewrite_type_in_next_line());
1513 type_offset.to_string(&context.config),
1520 pub fn rewrite_static(
1522 vis: &ast::Visibility,
1525 mutability: ast::Mutability,
1526 expr_opt: Option<&ptr::P<ast::Expr>>,
1529 context: &RewriteContext,
1530 ) -> Option<String> {
1531 let colon = colon_spaces(
1532 context.config.space_before_type_annotation(),
1533 context.config.space_after_type_annotation_colon(),
1535 let prefix = format!(
1537 format_visibility(vis),
1539 format_mutability(mutability),
1544 let ty_str = try_opt!(ty.rewrite(
1547 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)
1551 if let Some(expr) = expr_opt {
1552 let lhs = format!("{}{} =", prefix, ty_str);
1554 let remaining_width = context.config.max_width() - offset.block_indent - 1;
1559 Shape::legacy(remaining_width, offset.block_only()),
1561 recover_comment_removed(res, span, context, Shape::indented(offset, context.config))
1563 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1565 Some(format!("{}{};", prefix, ty_str))
1569 pub fn rewrite_associated_type(
1571 ty_opt: Option<&ptr::P<ast::Ty>>,
1572 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1573 context: &RewriteContext,
1575 ) -> Option<String> {
1576 let prefix = format!("type {}", ident);
1578 let type_bounds_str = if let Some(ty_param_bounds) = ty_param_bounds_opt {
1579 let shape = Shape::indented(indent, context.config);
1580 let bounds: &[_] = ty_param_bounds;
1581 let bound_str = try_opt!(
1584 .map(|ty_bound| ty_bound.rewrite(context, shape))
1585 .collect::<Option<Vec<_>>>()
1587 if bounds.len() > 0 {
1588 format!(": {}", join_bounds(context, shape, &bound_str))
1596 if let Some(ty) = ty_opt {
1597 let ty_str = try_opt!(ty.rewrite(
1600 context.config.max_width() - indent.block_indent - prefix.len() - 2,
1601 indent.block_only(),
1604 Some(format!("{} = {};", prefix, ty_str))
1606 Some(format!("{}{};", prefix, type_bounds_str))
1610 pub fn rewrite_associated_impl_type(
1612 defaultness: ast::Defaultness,
1613 ty_opt: Option<&ptr::P<ast::Ty>>,
1614 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1615 context: &RewriteContext,
1617 ) -> Option<String> {
1618 let result = try_opt!(rewrite_associated_type(
1621 ty_param_bounds_opt,
1627 ast::Defaultness::Default => Some(format!("default {}", result)),
1632 impl Rewrite for ast::FunctionRetTy {
1633 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1635 ast::FunctionRetTy::Default(_) => Some(String::new()),
1636 ast::FunctionRetTy::Ty(ref ty) => {
1637 let inner_width = try_opt!(shape.width.checked_sub(3));
1638 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1639 .map(|r| format!("-> {}", r))
1645 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1647 ast::TyKind::Infer => {
1648 let original = context.snippet(ty.span);
1655 impl Rewrite for ast::Arg {
1656 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1657 if is_named_arg(self) {
1658 let mut result = try_opt!(
1660 .rewrite(context, Shape::legacy(shape.width, shape.indent))
1663 if !is_empty_infer(context, &*self.ty) {
1664 if context.config.space_before_type_annotation() {
1665 result.push_str(" ");
1667 result.push_str(":");
1668 if context.config.space_after_type_annotation_colon() {
1669 result.push_str(" ");
1671 let max_width = try_opt!(shape.width.checked_sub(result.len()));
1672 let ty_str = try_opt!(self.ty.rewrite(
1674 Shape::legacy(max_width, shape.indent + result.len()),
1676 result.push_str(&ty_str);
1681 self.ty.rewrite(context, shape)
1686 fn rewrite_explicit_self(
1687 explicit_self: &ast::ExplicitSelf,
1689 context: &RewriteContext,
1690 ) -> Option<String> {
1691 match explicit_self.node {
1692 ast::SelfKind::Region(lt, m) => {
1693 let mut_str = format_mutability(m);
1696 let lifetime_str = try_opt!(l.rewrite(
1698 Shape::legacy(context.config.max_width(), Indent::empty()),
1700 Some(format!("&{} {}self", lifetime_str, mut_str))
1702 None => Some(format!("&{}self", mut_str)),
1705 ast::SelfKind::Explicit(ref ty, _) => {
1706 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1708 let mutability = explicit_self_mutability(&args[0]);
1709 let type_str = try_opt!(ty.rewrite(
1711 Shape::legacy(context.config.max_width(), Indent::empty()),
1716 format_mutability(mutability),
1720 ast::SelfKind::Value(_) => {
1721 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1723 let mutability = explicit_self_mutability(&args[0]);
1725 Some(format!("{}self", format_mutability(mutability)))
1730 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1731 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1732 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1733 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1740 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1741 if is_named_arg(arg) {
1748 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1750 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi,
1751 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi,
1752 _ => arg.ty.span.hi,
1756 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1757 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1758 ident.node != symbol::keywords::Invalid.ident()
1764 // Return type is (result, force_new_line_for_brace)
1766 context: &RewriteContext,
1770 generics: &ast::Generics,
1771 unsafety: ast::Unsafety,
1772 constness: ast::Constness,
1773 defaultness: ast::Defaultness,
1775 vis: &ast::Visibility,
1777 newline_brace: bool,
1780 ) -> Option<(String, bool)> {
1781 let mut force_new_line_for_brace = false;
1783 let where_clause = &generics.where_clause;
1785 let mut result = String::with_capacity(1024);
1786 // Vis unsafety abi.
1787 result.push_str(&*format_visibility(vis));
1789 if let ast::Defaultness::Default = defaultness {
1790 result.push_str("default ");
1793 if let ast::Constness::Const = constness {
1794 result.push_str("const ");
1797 result.push_str(::utils::format_unsafety(unsafety));
1799 if abi != abi::Abi::Rust {
1800 result.push_str(&::utils::format_abi(
1802 context.config.force_explicit_abi(),
1807 result.push_str("fn ");
1808 result.push_str(&ident.to_string());
1811 let overhead = if has_braces && !newline_brace {
1818 let shape = try_opt!(
1819 Shape::indented(indent + last_line_width(&result), context.config).sub_width(overhead)
1821 let g_span = mk_sp(span.lo, fd.output.span().lo);
1822 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1823 result.push_str(&generics_str);
1825 let snuggle_angle_bracket = generics_str
1828 .map_or(false, |l| l.trim_left().len() == 1);
1830 // Note that the width and indent don't really matter, we'll re-layout the
1831 // return type later anyway.
1832 let ret_str = try_opt!(
1834 .rewrite(&context, Shape::indented(indent, context.config))
1837 let multi_line_ret_str = ret_str.contains('\n');
1838 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1841 let (mut one_line_budget, mut multi_line_budget, mut arg_indent) =
1842 try_opt!(compute_budgets_for_args(
1851 if context.config.fn_args_layout() == IndentStyle::Block {
1852 arg_indent = indent.block_indent(context.config);
1854 multi_line_budget = context.config.max_width() - (arg_indent.width() + 1);
1858 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1864 // Check if vertical layout was forced.
1865 if one_line_budget == 0 {
1866 if snuggle_angle_bracket {
1869 if context.config.fn_args_paren_newline() {
1871 result.push_str(&arg_indent.to_string(context.config));
1872 if context.config.fn_args_layout() == IndentStyle::Visual {
1873 arg_indent = arg_indent + 1; // extra space for `(`
1877 result.push_str("(");
1878 if context.config.fn_args_layout() == IndentStyle::Visual {
1880 result.push_str(&arg_indent.to_string(context.config));
1887 if context.config.spaces_within_parens() && fd.inputs.len() > 0 && result.ends_with('(') {
1891 if multi_line_ret_str {
1892 one_line_budget = 0;
1895 // A conservative estimation, to goal is to be over all parens in generics
1896 let args_start = generics
1899 .map_or(span.lo, |tp| end_typaram(tp));
1900 let args_end = if fd.inputs.is_empty() {
1901 context.codemap.span_after(mk_sp(args_start, span.hi), ")")
1903 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi, span.hi);
1904 context.codemap.span_after(last_span, ")")
1906 let args_span = mk_sp(
1907 context.codemap.span_after(mk_sp(args_start, span.hi), "("),
1910 let arg_str = try_opt!(rewrite_args(
1913 fd.get_self().as_ref(),
1920 generics_str.contains('\n'),
1923 let multi_line_arg_str =
1924 arg_str.contains('\n') || arg_str.chars().last().map_or(false, |c| c == ',');
1926 let put_args_in_block = match context.config.fn_args_layout() {
1927 IndentStyle::Block => multi_line_arg_str || generics_str.contains('\n'),
1929 } && !fd.inputs.is_empty();
1931 let mut args_last_line_contains_comment = false;
1932 if put_args_in_block {
1933 arg_indent = indent.block_indent(context.config);
1935 result.push_str(&arg_indent.to_string(context.config));
1936 result.push_str(&arg_str);
1938 result.push_str(&indent.to_string(context.config));
1941 result.push_str(&arg_str);
1942 if context.config.spaces_within_parens() && fd.inputs.len() > 0 {
1945 // If the last line of args contains comment, we cannot put the closing paren
1946 // on the same line.
1950 .map_or(false, |last_line| last_line.contains("//"))
1952 args_last_line_contains_comment = true;
1954 result.push_str(&arg_indent.to_string(context.config));
1960 if !ret_str.is_empty() {
1961 let ret_should_indent = match context.config.fn_args_layout() {
1962 // If our args are block layout then we surely must have space.
1963 IndentStyle::Block if put_args_in_block => false,
1965 // If we've already gone multi-line, or the return type would push over the max
1966 // width, then put the return type on a new line. With the +1 for the signature
1967 // length an additional space between the closing parenthesis of the argument and
1968 // the arrow '->' is considered.
1969 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1971 // If there is no where clause, take into account the space after the return type
1973 if where_clause.predicates.is_empty() {
1977 let overlong_sig = sig_length > context.config.max_width();
1979 (!args_last_line_contains_comment) &&
1980 (result.contains('\n') || multi_line_ret_str || overlong_sig)
1983 let ret_indent = if ret_should_indent {
1984 let indent = match context.config.fn_return_indent() {
1985 ReturnIndent::WithWhereClause => indent + 4,
1986 // Aligning with non-existent args looks silly.
1987 _ if arg_str.is_empty() => {
1988 force_new_line_for_brace = true;
1991 // FIXME: we might want to check that using the arg indent
1992 // doesn't blow our budget, and if it does, then fallback to
1993 // the where clause indent.
1998 result.push_str(&indent.to_string(context.config));
2002 Indent::new(indent.block_indent, last_line_width(&result))
2005 if multi_line_ret_str || ret_should_indent {
2006 // Now that we know the proper indent and width, we need to
2007 // re-layout the return type.
2008 let ret_str = try_opt!(
2010 .rewrite(context, Shape::indented(ret_indent, context.config))
2012 result.push_str(&ret_str);
2014 result.push_str(&ret_str);
2017 // Comment between return type and the end of the decl.
2018 let snippet_lo = fd.output.span().hi;
2019 if where_clause.predicates.is_empty() {
2020 let snippet_hi = span.hi;
2021 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2022 // Try to preserve the layout of the original snippet.
2023 let original_starts_with_newline = snippet
2025 .map_or(false, |i| snippet[i..].starts_with('\n'));
2026 let original_ends_with_newline = snippet
2027 .rfind(|c| c != ' ')
2028 .map_or(false, |i| snippet[i..].ends_with('\n'));
2029 let snippet = snippet.trim();
2030 if !snippet.is_empty() {
2031 result.push(if original_starts_with_newline {
2036 result.push_str(snippet);
2037 if original_ends_with_newline {
2038 force_new_line_for_brace = true;
2042 // FIXME it would be nice to catch comments between the return type
2043 // and the where clause, but we don't have a span for the where
2048 let should_compress_where = match context.config.where_density() {
2049 Density::Compressed => !result.contains('\n') || put_args_in_block,
2050 Density::CompressedIfEmpty => !has_body && !result.contains('\n'),
2052 } || (put_args_in_block && ret_str.is_empty());
2054 let pos_before_where = match fd.output {
2055 ast::FunctionRetTy::Default(..) => args_span.hi,
2056 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi,
2058 if where_clause.predicates.len() == 1 && should_compress_where {
2059 let budget = try_opt!(
2063 .checked_sub(last_line_width(&result))
2065 if let Some(where_clause_str) = rewrite_where_clause(
2068 context.config.fn_brace_style(),
2069 Shape::legacy(budget, indent),
2070 Density::Compressed,
2073 put_args_in_block && ret_str.is_empty(),
2078 if !where_clause_str.contains('\n') {
2079 if last_line_width(&result) + where_clause_str.len() > context.config.max_width() {
2083 result.push_str(&where_clause_str);
2085 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2086 return Some((result, force_new_line_for_brace));
2091 let where_clause_str = try_opt!(rewrite_where_clause(
2094 context.config.fn_brace_style(),
2095 Shape::indented(indent, context.config),
2099 put_args_in_block && ret_str.is_empty(),
2105 result.push_str(&where_clause_str);
2107 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2108 return Some((result, force_new_line_for_brace));
2111 fn last_line_contains_single_line_comment(s: &str) -> bool {
2112 s.lines().last().map_or(false, |l| l.contains("//"))
2116 context: &RewriteContext,
2118 explicit_self: Option<&ast::ExplicitSelf>,
2119 one_line_budget: usize,
2120 multi_line_budget: usize,
2125 generics_str_contains_newline: bool,
2126 ) -> Option<String> {
2127 let mut arg_item_strs = try_opt!(
2130 arg.rewrite(&context, Shape::legacy(multi_line_budget, arg_indent))
2132 .collect::<Option<Vec<_>>>()
2135 // Account for sugary self.
2136 // FIXME: the comment for the self argument is dropped. This is blocked
2137 // on rust issue #27522.
2138 let min_args = explicit_self
2139 .and_then(|explicit_self| {
2140 rewrite_explicit_self(explicit_self, args, context)
2142 .map_or(1, |self_str| {
2143 arg_item_strs[0] = self_str;
2147 // Comments between args.
2148 let mut arg_items = Vec::new();
2150 arg_items.push(ListItem::from_str(""));
2153 // FIXME(#21): if there are no args, there might still be a comment, but
2154 // without spans for the comment or parens, there is no chance of
2155 // getting it right. You also don't get to put a comment on self, unless
2157 if args.len() >= min_args || variadic {
2158 let comment_span_start = if min_args == 2 {
2159 let second_arg_start = if arg_has_pattern(&args[1]) {
2164 let reduced_span = mk_sp(span.lo, second_arg_start);
2166 context.codemap.span_after_last(reduced_span, ",")
2171 enum ArgumentKind<'a> {
2172 Regular(&'a ast::Arg),
2176 let variadic_arg = if variadic {
2177 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi, span.hi);
2178 let variadic_start = context.codemap.span_after(variadic_span, "...") - BytePos(3);
2179 Some(ArgumentKind::Variadic(variadic_start))
2184 let more_items = itemize_list(
2186 args[min_args - 1..]
2188 .map(ArgumentKind::Regular)
2189 .chain(variadic_arg),
2192 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2193 ArgumentKind::Variadic(start) => start,
2196 ArgumentKind::Regular(arg) => arg.ty.span.hi,
2197 ArgumentKind::Variadic(start) => start + BytePos(3),
2200 ArgumentKind::Regular(..) => None,
2201 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2207 arg_items.extend(more_items);
2210 let fits_in_one_line = !generics_str_contains_newline &&
2211 (arg_items.len() == 0 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2213 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2214 item.item = Some(arg);
2217 let last_line_ends_with_comment = arg_items
2220 .and_then(|item| item.post_comment.as_ref())
2221 .map_or(false, |s| s.trim().starts_with("//"));
2223 let (indent, trailing_comma, end_with_newline) = match context.config.fn_args_layout() {
2224 IndentStyle::Block if fits_in_one_line => {
2226 indent.block_indent(context.config),
2227 SeparatorTactic::Never,
2231 IndentStyle::Block => {
2233 indent.block_indent(context.config),
2234 context.config.trailing_comma(),
2238 IndentStyle::Visual if last_line_ends_with_comment => {
2239 (arg_indent, context.config.trailing_comma(), true)
2241 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never, false),
2244 let tactic = definitive_tactic(
2246 context.config.fn_args_density().to_list_tactic(),
2249 let budget = match tactic {
2250 DefinitiveListTactic::Horizontal => one_line_budget,
2251 _ => multi_line_budget,
2254 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2256 let fmt = ListFormatting {
2259 trailing_separator: if variadic {
2260 SeparatorTactic::Never
2264 shape: Shape::legacy(budget, indent),
2265 ends_with_newline: end_with_newline,
2266 config: context.config,
2269 write_list(&arg_items, &fmt)
2272 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2273 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2274 ident.node != symbol::keywords::Invalid.ident()
2280 fn compute_budgets_for_args(
2281 context: &RewriteContext,
2285 newline_brace: bool,
2287 ) -> Option<((usize, usize, Indent))> {
2289 "compute_budgets_for_args {} {:?}, {}, {}",
2295 // Try keeping everything on the same line.
2296 if !result.contains('\n') {
2297 // 2 = `()`, 3 = `() `, space is before ret_string.
2298 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2299 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2309 let one_line_budget = context
2312 .checked_sub(used_space)
2315 if one_line_budget > 0 {
2317 let multi_line_overhead =
2318 indent.width() + result.len() + if newline_brace { 2 } else { 4 };
2319 let multi_line_budget =
2320 try_opt!(context.config.max_width().checked_sub(multi_line_overhead));
2325 indent + result.len() + 1,
2330 // Didn't work. we must force vertical layout and put args on a newline.
2331 let new_indent = indent.block_indent(context.config);
2332 // Account for `)` and possibly ` {`.
2333 let used_space = new_indent.width() + if ret_str_len == 0 { 1 } else { 3 };
2334 let max_space = try_opt!(context.config.max_width().checked_sub(used_space));
2335 Some((0, max_space, new_indent))
2338 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2339 match config.fn_brace_style() {
2340 BraceStyle::AlwaysNextLine => true,
2341 BraceStyle::SameLineWhere if !where_clause.predicates.is_empty() => true,
2346 fn rewrite_generics(
2347 context: &RewriteContext,
2348 generics: &ast::Generics,
2351 ) -> Option<String> {
2352 let g_shape = try_opt!(generics_shape_from_config(context.config, shape, 0));
2353 let one_line_width = shape.width.checked_sub(2).unwrap_or(0);
2354 rewrite_generics_inner(context, generics, g_shape, one_line_width, span).or_else(|| {
2355 rewrite_generics_inner(context, generics, g_shape, 0, span)
2359 fn rewrite_generics_inner(
2360 context: &RewriteContext,
2361 generics: &ast::Generics,
2363 one_line_width: usize,
2365 ) -> Option<String> {
2366 // FIXME: convert bounds to where clauses where they get too big or if
2367 // there is a where clause at all.
2368 let lifetimes: &[_] = &generics.lifetimes;
2369 let tys: &[_] = &generics.ty_params;
2370 if lifetimes.is_empty() && tys.is_empty() {
2371 return Some(String::new());
2374 // Strings for the generics.
2375 let lt_strs = lifetimes.iter().map(|lt| lt.rewrite(context, shape));
2376 let ty_strs = tys.iter().map(|ty_param| ty_param.rewrite(context, shape));
2378 // Extract comments between generics.
2379 let lt_spans = lifetimes.iter().map(|l| {
2380 let hi = if l.bounds.is_empty() {
2383 l.bounds[l.bounds.len() - 1].span.hi
2385 mk_sp(l.lifetime.span.lo, hi)
2387 let ty_spans = tys.iter().map(|ty| ty.span());
2389 let items = itemize_list(
2391 lt_spans.chain(ty_spans).zip(lt_strs.chain(ty_strs)),
2395 // FIXME: don't clone
2396 |&(_, ref str)| str.clone(),
2397 context.codemap.span_after(span, "<"),
2400 format_generics_item_list(context, items, shape, one_line_width)
2403 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2404 match config.generics_indent() {
2405 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2406 IndentStyle::Block => {
2410 .block_indent(config.tab_spaces())
2411 .with_max_width(config)
2417 pub fn format_generics_item_list<I>(
2418 context: &RewriteContext,
2421 one_line_budget: usize,
2424 I: Iterator<Item = ListItem>,
2426 let item_vec = items.collect::<Vec<_>>();
2428 let tactic = definitive_tactic(&item_vec, ListTactic::HorizontalVertical, one_line_budget);
2429 let ends_with_newline = context.config.generics_indent() == IndentStyle::Block &&
2430 tactic == DefinitiveListTactic::Vertical;
2431 let fmt = ListFormatting {
2434 trailing_separator: if context.config.generics_indent() == IndentStyle::Visual {
2435 SeparatorTactic::Never
2437 context.config.trailing_comma()
2440 ends_with_newline: ends_with_newline,
2441 config: context.config,
2444 let list_str = try_opt!(write_list(&item_vec, &fmt));
2446 Some(wrap_generics_with_angle_brackets(
2453 pub fn wrap_generics_with_angle_brackets(
2454 context: &RewriteContext,
2456 list_offset: Indent,
2458 if context.config.generics_indent() == IndentStyle::Block &&
2459 (list_str.contains('\n') || list_str.ends_with(','))
2463 list_offset.to_string(context.config),
2466 .block_unindent(context.config)
2467 .to_string(context.config)
2469 } else if context.config.spaces_within_angle_brackets() {
2470 format!("< {} >", list_str)
2472 format!("<{}>", list_str)
2476 fn rewrite_trait_bounds(
2477 context: &RewriteContext,
2478 type_param_bounds: &ast::TyParamBounds,
2480 ) -> Option<String> {
2481 let bounds: &[_] = type_param_bounds;
2483 if bounds.is_empty() {
2484 return Some(String::new());
2486 let bound_str = try_opt!(
2489 .map(|ty_bound| ty_bound.rewrite(&context, shape))
2490 .collect::<Option<Vec<_>>>()
2492 Some(format!(": {}", join_bounds(context, shape, &bound_str)))
2495 fn rewrite_where_clause_rfc_style(
2496 context: &RewriteContext,
2497 where_clause: &ast::WhereClause,
2500 suppress_comma: bool,
2501 // where clause can be kept on the current line.
2503 span_end: Option<BytePos>,
2505 span_end_before_where: BytePos,
2506 ) -> Option<String> {
2507 let block_shape = shape.block().with_max_width(context.config);
2509 let (span_before, span_after) =
2510 missing_span_before_after_where(context, span.hi, span_end_before_where, where_clause);
2511 let (comment_before, comment_after) = try_opt!(rewrite_comments_before_after_where(
2518 let starting_newline = if snuggle && comment_before.is_empty() {
2521 "\n".to_owned() + &block_shape.indent.to_string(context.config)
2524 let clause_shape = block_shape.block_indent(context.config.tab_spaces());
2525 // each clause on one line, trailing comma (except if suppress_comma)
2526 let span_start = where_clause.predicates[0].span().lo;
2527 // If we don't have the start of the next span, then use the end of the
2528 // predicates, but that means we miss comments.
2529 let len = where_clause.predicates.len();
2530 let end_of_preds = where_clause.predicates[len - 1].span().hi;
2531 let span_end = span_end.unwrap_or(end_of_preds);
2532 let items = itemize_list(
2534 where_clause.predicates.iter(),
2536 |pred| pred.span().lo,
2537 |pred| pred.span().hi,
2538 |pred| pred.rewrite(context, block_shape),
2542 let comma_tactic = if suppress_comma {
2543 SeparatorTactic::Never
2545 context.config.trailing_comma()
2548 let fmt = ListFormatting {
2549 tactic: DefinitiveListTactic::Vertical,
2551 trailing_separator: comma_tactic,
2552 shape: clause_shape,
2553 ends_with_newline: true,
2554 config: context.config,
2556 let preds_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
2558 let newline_before_where = if comment_before.is_empty() || comment_before.ends_with('\n') {
2561 "\n".to_owned() + &shape.indent.to_string(context.config)
2563 let newline_after_where = if comment_after.is_empty() {
2566 "\n".to_owned() + &clause_shape.indent.to_string(context.config)
2569 "{}{}{}where{}{}\n{}{}",
2572 newline_before_where,
2573 newline_after_where,
2575 clause_shape.indent.to_string(context.config),
2580 fn rewrite_where_clause(
2581 context: &RewriteContext,
2582 where_clause: &ast::WhereClause,
2583 brace_style: BraceStyle,
2587 suppress_comma: bool,
2589 span_end: Option<BytePos>,
2591 span_end_before_where: BytePos,
2592 ) -> Option<String> {
2593 if where_clause.predicates.is_empty() {
2594 return Some(String::new());
2597 if context.config.where_style() == Style::Rfc {
2598 return rewrite_where_clause_rfc_style(
2607 span_end_before_where,
2611 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2613 let offset = match context.config.where_pred_indent() {
2614 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2615 // 6 = "where ".len()
2616 IndentStyle::Visual => shape.indent + extra_indent + 6,
2618 // FIXME: if where_pred_indent != Visual, then the budgets below might
2619 // be out by a char or two.
2621 let budget = context.config.max_width() - offset.width();
2622 let span_start = where_clause.predicates[0].span().lo;
2623 // If we don't have the start of the next span, then use the end of the
2624 // predicates, but that means we miss comments.
2625 let len = where_clause.predicates.len();
2626 let end_of_preds = where_clause.predicates[len - 1].span().hi;
2627 let span_end = span_end.unwrap_or(end_of_preds);
2628 let items = itemize_list(
2630 where_clause.predicates.iter(),
2632 |pred| pred.span().lo,
2633 |pred| pred.span().hi,
2634 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2638 let item_vec = items.collect::<Vec<_>>();
2639 // FIXME: we don't need to collect here if the where_layout isn't
2640 // HorizontalVertical.
2641 let tactic = definitive_tactic(&item_vec, context.config.where_layout(), budget);
2643 let mut comma_tactic = context.config.trailing_comma();
2644 // Kind of a hack because we don't usually have trailing commas in where clauses.
2645 if comma_tactic == SeparatorTactic::Vertical || suppress_comma {
2646 comma_tactic = SeparatorTactic::Never;
2649 let fmt = ListFormatting {
2652 trailing_separator: comma_tactic,
2653 shape: Shape::legacy(budget, offset),
2654 ends_with_newline: true,
2655 config: context.config,
2657 let preds_str = try_opt!(write_list(&item_vec, &fmt));
2659 let end_length = if terminator == "{" {
2660 // If the brace is on the next line we don't need to count it otherwise it needs two
2663 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2664 BraceStyle::PreferSameLine => 2,
2666 } else if terminator == "=" {
2671 if density == Density::Tall || preds_str.contains('\n') ||
2672 shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2676 (shape.indent + extra_indent).to_string(context.config),
2680 Some(format!(" where {}", preds_str))
2684 fn missing_span_before_after_where(
2685 context: &RewriteContext,
2687 before_item_span_end: BytePos,
2688 where_clause: &ast::WhereClause,
2690 let snippet = context.snippet(mk_sp(before_item_span_end, item_end));
2691 let pos_before_where =
2692 before_item_span_end + BytePos(snippet.find_uncommented("where").unwrap() as u32);
2693 let missing_span_before = mk_sp(before_item_span_end, pos_before_where);
2695 let pos_after_where = pos_before_where + BytePos(5);
2696 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo);
2697 (missing_span_before, missing_span_after)
2700 fn rewrite_missing_comment_in_where(
2701 context: &RewriteContext,
2704 ) -> Option<String> {
2705 let comment = comment.trim();
2706 if comment.is_empty() {
2709 rewrite_comment(comment, false, shape, context.config)
2713 fn rewrite_comments_before_after_where(
2714 context: &RewriteContext,
2715 span_before_where: Span,
2716 span_after_where: Span,
2718 ) -> Option<(String, String)> {
2719 let before_comment = try_opt!(rewrite_missing_comment_in_where(
2721 &context.snippet(span_before_where),
2724 let after_comment = try_opt!(rewrite_missing_comment_in_where(
2726 &context.snippet(span_after_where),
2727 shape.block_indent(context.config.tab_spaces()),
2729 Some((before_comment, after_comment))
2732 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2733 format!("{}{}{}", format_visibility(vis), item_name, ident)
2737 context: &RewriteContext,
2738 generics: &ast::Generics,
2741 brace_style: BraceStyle,
2742 force_same_line_brace: bool,
2746 ) -> Option<String> {
2747 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2748 let mut result = try_opt!(rewrite_generics(context, generics, shape, span));
2750 if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2751 let budget = try_opt!(
2755 .checked_sub(last_line_width(&result))
2757 let where_clause_str = try_opt!(rewrite_where_clause(
2759 &generics.where_clause,
2761 Shape::legacy(budget, offset.block_only()),
2765 trimmed_last_line_width(&result) == 1,
2770 result.push_str(&where_clause_str);
2771 let same_line_brace = force_same_line_brace ||
2772 (generics.where_clause.predicates.is_empty() && trimmed_last_line_width(&result) == 1);
2773 if !same_line_brace &&
2774 (brace_style == BraceStyle::SameLineWhere ||
2775 brace_style == BraceStyle::AlwaysNextLine)
2778 result.push_str(&offset.block_only().to_string(context.config));
2782 result.push_str(opener);
2784 if force_same_line_brace || trimmed_last_line_width(&result) == 1 ||
2785 brace_style != BraceStyle::AlwaysNextLine
2790 result.push_str(&offset.block_only().to_string(context.config));
2792 result.push_str(opener);