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.
15 use syntax::{abi, ast, ptr, symbol};
16 use syntax::ast::ImplItem;
17 use syntax::codemap::{BytePos, Span};
19 use {Indent, Shape, Spanned};
20 use codemap::SpanUtils;
21 use comment::{contains_comment, recover_comment_removed, rewrite_comment, FindUncommented};
22 use config::{BraceStyle, Config, Density, IndentStyle, ReturnIndent, Style};
23 use expr::{format_expr, is_empty_block, is_simple_block_stmt, rewrite_assign_rhs,
24 rewrite_call_inner, ExprType};
25 use lists::{definitive_tactic, itemize_list, write_list, DefinitiveListTactic, ListFormatting,
26 ListItem, ListTactic, SeparatorTactic};
27 use rewrite::{Rewrite, RewriteContext};
28 use types::join_bounds;
29 use utils::{colon_spaces, contains_skip, end_typaram, format_defaultness, format_mutability,
30 format_unsafety, format_visibility, last_line_width, mk_sp, semicolon_for_expr,
31 stmt_expr, trim_newlines, trimmed_last_line_width, wrap_str};
32 use vertical::rewrite_with_alignment;
33 use visitor::FmtVisitor;
35 fn type_annotation_separator(config: &Config) -> &str {
37 config.space_before_type_annotation(),
38 config.space_after_type_annotation_colon(),
43 // Statements of the form
44 // let pat: ty = init;
45 impl Rewrite for ast::Local {
46 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
48 "Local::rewrite {:?} {} {:?}",
53 let mut result = "let ".to_owned();
56 let pat_shape = try_opt!(shape.offset_left(4));
58 let pat_shape = try_opt!(pat_shape.sub_width(1));
59 let pat_str = try_opt!(self.pat.rewrite(&context, pat_shape));
60 result.push_str(&pat_str);
62 // String that is placed within the assignment pattern and expression.
64 let mut infix = String::new();
66 if let Some(ref ty) = self.ty {
67 let separator = type_annotation_separator(context.config);
68 let indent = shape.indent + last_line_width(&result) + separator.len();
70 let budget = try_opt!(shape.width.checked_sub(indent.width() + 1));
71 let rewrite = try_opt!(ty.rewrite(context, Shape::legacy(budget, indent)));
73 infix.push_str(separator);
74 infix.push_str(&rewrite);
77 if self.init.is_some() {
84 result.push_str(&infix);
86 if let Some(ref ex) = self.init {
87 // 1 = trailing semicolon;
88 let nested_shape = try_opt!(shape.sub_width(1));
90 result = try_opt!(rewrite_assign_rhs(&context, result, ex, nested_shape));
98 // TODO convert to using rewrite style rather than visitor
99 // TODO format modules in this style
102 keyword: &'static str,
104 vis: Option<&'a ast::Visibility>,
105 body: Vec<BodyElement<'a>>,
110 fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Item<'a> {
111 let abi = if fm.abi == abi::Abi::C && !config.force_explicit_abi() {
114 format!("extern {}", fm.abi)
122 .map(|i| BodyElement::ForeignItem(i))
129 enum BodyElement<'a> {
130 // Stmt(&'a ast::Stmt),
131 // Field(&'a ast::Field),
132 // Variant(&'a ast::Variant),
133 // Item(&'a ast::Item),
134 ForeignItem(&'a ast::ForeignItem),
137 impl<'a> FmtVisitor<'a> {
138 fn format_item(&mut self, item: Item) {
139 self.buffer.push_str(&item.abi);
140 self.buffer.push_str(" ");
142 let snippet = self.snippet(item.span);
143 let brace_pos = snippet.find_uncommented("{").unwrap();
145 self.buffer.push_str("{");
146 if !item.body.is_empty() || contains_comment(&snippet[brace_pos..]) {
147 // FIXME: this skips comments between the extern keyword and the opening
149 self.last_pos = item.span.lo + BytePos(brace_pos as u32 + 1);
150 self.block_indent = self.block_indent.block_indent(self.config);
152 if item.body.is_empty() {
153 self.format_missing_no_indent(item.span.hi - BytePos(1));
154 self.block_indent = self.block_indent.block_unindent(self.config);
157 .push_str(&self.block_indent.to_string(self.config));
159 for item in &item.body {
160 self.format_body_element(item);
163 self.block_indent = self.block_indent.block_unindent(self.config);
164 self.format_missing_with_indent(item.span.hi - BytePos(1));
168 self.buffer.push_str("}");
169 self.last_pos = item.span.hi;
172 fn format_body_element(&mut self, element: &BodyElement) {
174 BodyElement::ForeignItem(ref item) => self.format_foreign_item(item),
178 pub fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) {
179 let item = Item::from_foreign_mod(fm, span, self.config);
180 self.format_item(item);
183 fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
184 self.format_missing_with_indent(item.span.lo);
185 // Drop semicolon or it will be interpreted as comment.
186 // FIXME: this may be a faulty span from libsyntax.
187 let span = mk_sp(item.span.lo, item.span.hi - BytePos(1));
190 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
191 let indent = self.block_indent;
192 let rewrite = rewrite_fn_base(
198 ast::Unsafety::Normal,
199 ast::Constness::NotConst,
200 ast::Defaultness::Final,
201 // These are not actually rust functions,
202 // but we format them as such.
212 Some((new_fn, _)) => {
213 self.buffer.push_str(&new_fn);
214 self.buffer.push_str(";");
216 None => self.format_missing(item.span.hi),
219 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
220 // FIXME(#21): we're dropping potential comments in between the
221 // function keywords here.
222 let vis = format_visibility(&item.vis);
223 let mut_str = if is_mutable { "mut " } else { "" };
224 let prefix = format!("{}static {}{}: ", vis, mut_str, item.ident);
225 let offset = self.block_indent + prefix.len();
227 let shape = Shape::indented(offset, self.config).sub_width(1).unwrap();
228 let rewrite = ty.rewrite(&self.get_context(), shape);
232 self.buffer.push_str(&prefix);
233 self.buffer.push_str(&result);
234 self.buffer.push_str(";");
236 None => self.format_missing(item.span.hi),
241 self.last_pos = item.span.hi;
249 generics: &ast::Generics,
250 unsafety: ast::Unsafety,
251 constness: ast::Constness,
252 defaultness: ast::Defaultness,
254 vis: &ast::Visibility,
257 ) -> Option<String> {
258 let mut newline_brace = newline_for_brace(self.config, &generics.where_clause);
259 let context = self.get_context();
261 let block_snippet = self.snippet(mk_sp(block.span.lo, block.span.hi));
262 let has_body = !block_snippet[1..block_snippet.len() - 1].trim().is_empty() ||
263 !context.config.fn_empty_single_line();
265 let (mut result, force_newline_brace) = try_opt!(rewrite_fn_base(
282 if force_newline_brace {
283 newline_brace = true;
284 } else if self.config.fn_brace_style() != BraceStyle::AlwaysNextLine &&
285 !result.contains('\n')
287 newline_brace = false;
290 // Prepare for the function body by possibly adding a newline and
292 // FIXME we'll miss anything between the end of the signature and the
293 // start of the body, but we need more spans from the compiler to solve
297 result.push_str(&indent.to_string(self.config));
302 self.single_line_fn(&result, block).or_else(|| Some(result))
305 pub fn rewrite_required_fn(
309 sig: &ast::MethodSig,
311 ) -> Option<String> {
312 // Drop semicolon or it will be interpreted as comment.
313 let span = mk_sp(span.lo, span.hi - BytePos(1));
314 let context = self.get_context();
316 let (mut result, _) = try_opt!(rewrite_fn_base(
324 ast::Defaultness::Final,
326 &ast::Visibility::Inherited,
333 // Re-attach semicolon
339 fn single_line_fn(&self, fn_str: &str, block: &ast::Block) -> Option<String> {
340 if fn_str.contains('\n') {
344 let codemap = self.get_context().codemap;
346 if self.config.fn_empty_single_line() && is_empty_block(block, codemap) &&
347 self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width()
349 return Some(format!("{}{{}}", fn_str));
352 if self.config.fn_single_line() && is_simple_block_stmt(block, codemap) {
354 if let Some(ref stmt) = block.stmts.first() {
355 match stmt_expr(stmt) {
357 let suffix = if semicolon_for_expr(&self.get_context(), e) {
367 Shape::indented(self.block_indent, self.config),
368 ).map(|s| s + suffix)
369 .or_else(|| Some(self.snippet(e.span)))
371 None => stmt.rewrite(
373 Shape::indented(self.block_indent, self.config),
381 if let Some(res) = rewrite {
382 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
383 if !res.contains('\n') && width <= self.config.max_width() {
384 return Some(format!("{}{{ {} }}", fn_str, res));
395 vis: &ast::Visibility,
396 enum_def: &ast::EnumDef,
397 generics: &ast::Generics,
400 let enum_header = format_header("enum ", ident, vis);
401 self.buffer.push_str(&enum_header);
403 let enum_snippet = self.snippet(span);
404 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
405 let body_start = span.lo + BytePos(brace_pos as u32 + 1);
406 let generics_str = format_generics(
411 self.config.item_brace_style(),
412 enum_def.variants.is_empty(),
414 mk_sp(span.lo, body_start),
415 last_line_width(&enum_header),
417 self.buffer.push_str(&generics_str);
419 self.last_pos = body_start;
421 self.block_indent = self.block_indent.block_indent(self.config);
422 let variant_list = self.format_variant_list(enum_def, body_start, span.hi - BytePos(1));
424 Some(ref body_str) => self.buffer.push_str(body_str),
425 None => if contains_comment(&enum_snippet[brace_pos..]) {
426 self.format_missing_no_indent(span.hi - BytePos(1))
428 self.format_missing(span.hi - BytePos(1))
431 self.block_indent = self.block_indent.block_unindent(self.config);
433 if variant_list.is_some() || contains_comment(&enum_snippet[brace_pos..]) {
435 .push_str(&self.block_indent.to_string(self.config));
437 self.buffer.push_str("}");
438 self.last_pos = span.hi;
441 // Format the body of an enum definition
442 fn format_variant_list(
444 enum_def: &ast::EnumDef,
447 ) -> Option<String> {
448 if enum_def.variants.is_empty() {
451 let mut result = String::with_capacity(1024);
453 let indentation = self.block_indent.to_string(self.config);
454 result.push_str(&indentation);
456 let items = itemize_list(
458 enum_def.variants.iter(),
460 |f| if !f.node.attrs.is_empty() {
461 f.node.attrs[0].span.lo
466 |f| self.format_variant(f),
471 let shape = Shape::indented(self.block_indent, self.config)
474 let fmt = ListFormatting {
475 tactic: DefinitiveListTactic::Vertical,
477 trailing_separator: self.config.trailing_comma(),
479 ends_with_newline: true,
480 preserve_newline: true,
484 let list = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
485 result.push_str(&list);
490 // Variant of an enum.
491 fn format_variant(&self, field: &ast::Variant) -> Option<String> {
492 if contains_skip(&field.node.attrs) {
493 let lo = field.node.attrs[0].span.lo;
494 let span = mk_sp(lo, field.span.hi);
495 return Some(self.snippet(span));
498 let context = self.get_context();
499 let indent = self.block_indent;
500 let mut result = try_opt!(
504 .rewrite(&context, Shape::indented(indent, self.config))
506 if !result.is_empty() {
508 width: context.config.max_width(),
509 indent: self.block_indent,
510 offset: self.block_indent.alignment,
512 let missing_comment = rewrite_missing_comment_on_field(
515 field.node.attrs[field.node.attrs.len() - 1].span.hi,
518 ).unwrap_or(String::new());
519 result.push_str(&missing_comment);
522 let variant_body = match field.node.data {
523 ast::VariantData::Tuple(..) | ast::VariantData::Struct(..) => {
524 // FIXME: Should limit the width, as we have a trailing comma
529 &ast::Visibility::Inherited,
534 Some(self.config.struct_variant_width()),
537 ast::VariantData::Unit(..) => {
538 let tag = if let Some(ref expr) = field.node.disr_expr {
539 format!("{} = {}", field.node.name, self.snippet(expr.span))
541 field.node.name.to_string()
546 self.config.max_width(),
547 Shape::indented(indent, self.config),
552 if let Some(variant_str) = variant_body {
553 result.push_str(&variant_str);
562 context: &RewriteContext,
565 where_span_end: Option<BytePos>,
566 ) -> Option<String> {
567 if let ast::ItemKind::Impl(_, _, _, ref generics, _, ref self_ty, ref items) = item.node {
568 let mut result = String::new();
569 let ref_and_type = try_opt!(format_impl_ref_and_type(context, item, offset));
570 result.push_str(&ref_and_type);
572 let where_budget = if result.contains('\n') {
573 context.config.max_width()
578 .checked_sub(last_line_width(&result))
581 let where_clause_str = try_opt!(rewrite_where_clause(
583 &generics.where_clause,
584 context.config.item_brace_style(),
585 Shape::legacy(where_budget, offset.block_only()),
586 context.config.where_density(),
589 last_line_width(&ref_and_type) == 1,
595 if try_opt!(is_impl_single_line(
602 result.push_str(&where_clause_str);
603 if where_clause_str.contains('\n') {
604 let white_space = offset.to_string(context.config);
605 result.push_str(&format!("\n{}{{\n{}}}", &white_space, &white_space));
607 result.push_str(" {}");
612 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
614 let width = offset.block_indent + context.config.tab_spaces() - 1;
615 let where_indent = Indent::new(0, width);
616 result.push_str(&where_indent.to_string(context.config));
618 result.push_str(&where_clause_str);
620 match context.config.item_brace_style() {
621 BraceStyle::AlwaysNextLine => {
623 result.push_str(&offset.to_string(context.config));
625 BraceStyle::PreferSameLine => result.push(' '),
626 BraceStyle::SameLineWhere => if !where_clause_str.is_empty() {
628 result.push_str(&offset.to_string(context.config));
636 let snippet = context.snippet(item.span);
637 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
639 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
640 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
641 visitor.block_indent = offset.block_only().block_indent(context.config);
642 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
644 visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner);
646 visitor.visit_impl_item(item);
649 visitor.format_missing(item.span.hi - BytePos(1));
651 let inner_indent_str = visitor.block_indent.to_string(context.config);
652 let outer_indent_str = offset.block_only().to_string(context.config);
655 result.push_str(&inner_indent_str);
656 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
658 result.push_str(&outer_indent_str);
661 if result.chars().last().unwrap() == '{' {
663 result.push_str(&offset.to_string(context.config));
673 fn is_impl_single_line(
674 context: &RewriteContext,
677 where_clause_str: &str,
680 let snippet = context.snippet(item.span);
681 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
684 context.config.impl_empty_single_line() && items.is_empty() &&
685 result.len() + where_clause_str.len() <= context.config.max_width() &&
686 !contains_comment(&snippet[open_pos..]),
690 fn format_impl_ref_and_type(
691 context: &RewriteContext,
694 ) -> Option<String> {
695 if let ast::ItemKind::Impl(
705 let mut result = String::new();
707 result.push_str(&format_visibility(&item.vis));
708 result.push_str(&format_defaultness(defaultness));
709 result.push_str(format_unsafety(unsafety));
710 result.push_str("impl");
712 let lo = context.codemap.span_after(item.span, "impl");
713 let hi = match *trait_ref {
714 Some(ref tr) => tr.path.span.lo,
715 None => self_ty.span.lo,
717 let shape = try_opt!(generics_shape_from_config(
719 Shape::indented(offset + last_line_width(&result), context.config),
722 let one_line_budget = try_opt!(shape.width.checked_sub(last_line_width(&result) + 2));
723 let generics_str = try_opt!(rewrite_generics_inner(
731 let polarity_str = if polarity == ast::ImplPolarity::Negative {
737 if let Some(ref trait_ref) = *trait_ref {
738 let result_len = result.len();
739 if let Some(trait_ref_str) = rewrite_trait_ref(
748 result.push_str(&trait_ref_str);
750 let generics_str = try_opt!(rewrite_generics_inner(
757 result.push_str(&try_opt!(rewrite_trait_ref(
768 result.push_str(&generics_str);
771 // Try to put the self type in a single line.
773 let trait_ref_overhead = if trait_ref.is_some() { 4 } else { 0 };
774 let curly_brace_overhead = if generics.where_clause.predicates.is_empty() {
775 // If there is no where clause adapt budget for type formatting to take space and curly
776 // brace into account.
777 match context.config.item_brace_style() {
778 BraceStyle::AlwaysNextLine => 0,
784 let used_space = last_line_width(&result) + trait_ref_overhead + curly_brace_overhead;
785 // 1 = space before the type.
789 .checked_sub(used_space + 1)
791 if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) {
792 if !self_ty_str.contains('\n') {
793 if trait_ref.is_some() {
794 result.push_str(" for ");
798 result.push_str(&self_ty_str);
803 // Couldn't fit the self type on a single line, put it on a new line.
805 // Add indentation of one additional tab.
806 let new_line_offset = offset.block_indent(context.config);
807 result.push_str(&new_line_offset.to_string(context.config));
808 if trait_ref.is_some() {
809 result.push_str("for ");
811 let budget = context.config.max_width() - last_line_width(&result);
812 let type_offset = match context.config.where_style() {
813 Style::Legacy => new_line_offset + trait_ref_overhead,
814 Style::Rfc => new_line_offset,
816 result.push_str(&*try_opt!(
817 self_ty.rewrite(context, Shape::legacy(budget, type_offset))
825 fn rewrite_trait_ref(
826 context: &RewriteContext,
827 trait_ref: &ast::TraitRef,
833 ) -> Option<String> {
834 // 1 = space between generics and trait_ref
835 let used_space = 1 + polarity_str.len() + if generics_str.contains('\n') {
836 last_line_width(&generics_str)
838 result_len + generics_str.len()
840 let shape = Shape::indented(offset + used_space, context.config);
841 if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) {
842 if !(retry && trait_ref_str.contains('\n')) {
851 // We could not make enough space for trait_ref, so put it on new line.
853 let offset = offset.block_indent(context.config);
854 let shape = Shape::indented(offset, context.config);
855 let trait_ref_str = try_opt!(trait_ref.rewrite(context, shape));
859 &offset.to_string(context.config),
868 pub fn format_struct(
869 context: &RewriteContext,
872 vis: &ast::Visibility,
873 struct_def: &ast::VariantData,
874 generics: Option<&ast::Generics>,
877 one_line_width: Option<usize>,
878 ) -> Option<String> {
880 ast::VariantData::Unit(..) => Some(format_unit_struct(item_name, ident, vis)),
881 ast::VariantData::Tuple(ref fields, _) => format_tuple_struct(
891 ast::VariantData::Struct(ref fields, _) => format_struct_struct(
905 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
906 if let ast::ItemKind::Trait(unsafety, ref generics, ref type_param_bounds, ref trait_items) =
909 let mut result = String::new();
910 let header = format!(
912 format_visibility(&item.vis),
913 format_unsafety(unsafety),
917 result.push_str(&header);
919 let body_lo = context.codemap.span_after(item.span, "{");
921 let shape = Shape::indented(offset + last_line_width(&result), context.config);
922 let generics_str = try_opt!(rewrite_generics(
926 mk_sp(item.span.lo, body_lo),
928 result.push_str(&generics_str);
930 let trait_bound_str = try_opt!(rewrite_trait_bounds(
933 Shape::indented(offset, context.config),
935 // If the trait, generics, and trait bound cannot fit on the same line,
936 // put the trait bounds on an indented new line
937 if offset.width() + last_line_width(&result) + trait_bound_str.len() >
938 context.config.comment_width()
941 let trait_indent = offset.block_only().block_indent(context.config);
942 result.push_str(&trait_indent.to_string(context.config));
944 result.push_str(&trait_bound_str);
946 let has_body = !trait_items.is_empty();
948 let where_density = if (context.config.where_density() == Density::Compressed &&
949 (!result.contains('\n') || context.config.fn_args_layout() == IndentStyle::Block)) ||
950 (context.config.fn_args_layout() == IndentStyle::Block && result.is_empty()) ||
951 (context.config.where_density() == Density::CompressedIfEmpty && !has_body &&
952 !result.contains('\n'))
959 let where_budget = try_opt!(
963 .checked_sub(last_line_width(&result))
965 let pos_before_where = if type_param_bounds.is_empty() {
966 if generics.where_clause.predicates.is_empty() {
967 // We do not use this, so it does not matter
970 let snippet = context.snippet(item.span);
971 let where_pos = snippet.find_uncommented("where");
972 item.span.lo + where_pos.map_or(BytePos(0), |p| BytePos(p as u32))
975 type_param_bounds[type_param_bounds.len() - 1].span().hi
977 let where_clause_str = try_opt!(rewrite_where_clause(
979 &generics.where_clause,
980 context.config.item_brace_style(),
981 Shape::legacy(where_budget, offset.block_only()),
985 trait_bound_str.is_empty() && last_line_width(&generics_str) == 1,
990 // If the where clause cannot fit on the same line,
991 // put the where clause on a new line
992 if !where_clause_str.contains('\n') &&
993 last_line_width(&result) + where_clause_str.len() + offset.width() >
994 context.config.comment_width()
997 let width = offset.block_indent + context.config.tab_spaces() - 1;
998 let where_indent = Indent::new(0, width);
999 result.push_str(&where_indent.to_string(context.config));
1001 result.push_str(&where_clause_str);
1003 match context.config.item_brace_style() {
1004 BraceStyle::AlwaysNextLine => {
1006 result.push_str(&offset.to_string(context.config));
1008 BraceStyle::PreferSameLine => result.push(' '),
1009 BraceStyle::SameLineWhere => if !where_clause_str.is_empty() &&
1010 (!trait_items.is_empty() || result.contains('\n'))
1013 result.push_str(&offset.to_string(context.config));
1020 let snippet = context.snippet(item.span);
1021 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
1023 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
1024 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
1025 visitor.block_indent = offset.block_only().block_indent(context.config);
1026 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
1028 for item in trait_items {
1029 visitor.visit_trait_item(item);
1032 visitor.format_missing(item.span.hi - BytePos(1));
1034 let inner_indent_str = visitor.block_indent.to_string(context.config);
1035 let outer_indent_str = offset.block_only().to_string(context.config);
1038 result.push_str(&inner_indent_str);
1039 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
1041 result.push_str(&outer_indent_str);
1042 } else if result.contains('\n') {
1053 fn format_unit_struct(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
1054 format!("{};", format_header(item_name, ident, vis))
1057 pub fn format_struct_struct(
1058 context: &RewriteContext,
1061 vis: &ast::Visibility,
1062 fields: &[ast::StructField],
1063 generics: Option<&ast::Generics>,
1066 one_line_width: Option<usize>,
1067 ) -> Option<String> {
1068 let mut result = String::with_capacity(1024);
1070 let header_str = format_header(item_name, ident, vis);
1071 result.push_str(&header_str);
1073 let body_lo = context.codemap.span_after(span, "{");
1075 let generics_str = match generics {
1076 Some(g) => try_opt!(format_generics(
1081 context.config.item_brace_style(),
1084 mk_sp(span.lo, body_lo),
1085 last_line_width(&result),
1088 // 3 = ` {}`, 2 = ` {`.
1089 let overhead = if fields.is_empty() { 3 } else { 2 };
1090 if (context.config.item_brace_style() == BraceStyle::AlwaysNextLine &&
1091 !fields.is_empty()) ||
1095 .checked_sub(result.len())
1096 .unwrap_or(0) < overhead
1098 format!("\n{}{{", offset.block_only().to_string(context.config))
1105 let overhead = if fields.is_empty() { 1 } else { 0 };
1106 let max_len = context
1109 .checked_sub(offset.width())
1111 if !generics_str.contains('\n') && result.len() + generics_str.len() + overhead > max_len {
1113 result.push_str(&offset.to_string(context.config));
1114 result.push_str(&generics_str.trim_left());
1116 result.push_str(&generics_str);
1119 if fields.is_empty() {
1120 let snippet = context.snippet(mk_sp(body_lo, span.hi - BytePos(1)));
1121 if snippet.trim().is_empty() {
1123 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1125 result.push_str(&snippet.trim_right());
1127 result.push_str(&offset.to_string(context.config));
1129 result.push_str(&snippet);
1132 return Some(result);
1136 let one_line_budget = context
1139 .checked_sub(result.len() + 3 + offset.width())
1141 let one_line_budget =
1142 one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
1144 let items_str = try_opt!(rewrite_with_alignment(
1147 Shape::indented(offset, context.config),
1148 mk_sp(body_lo, span.hi),
1152 if !items_str.contains('\n') && !result.contains('\n') && items_str.len() <= one_line_budget {
1153 Some(format!("{} {} }}", result, items_str))
1159 .block_indent(context.config)
1160 .to_string(context.config),
1162 offset.to_string(context.config)
1167 fn format_tuple_struct(
1168 context: &RewriteContext,
1171 vis: &ast::Visibility,
1172 fields: &[ast::StructField],
1173 generics: Option<&ast::Generics>,
1176 ) -> Option<String> {
1177 let mut result = String::with_capacity(1024);
1179 let header_str = format_header(item_name, ident, vis);
1180 result.push_str(&header_str);
1182 let body_lo = if fields.is_empty() {
1183 context.codemap.span_after(span, "(")
1187 let body_hi = if fields.is_empty() {
1188 context.codemap.span_after(span, ")")
1190 // This is a dirty hack to work around a missing `)` from the span of the last field.
1191 let last_arg_span = fields[fields.len() - 1].span;
1192 if context.snippet(last_arg_span).ends_with(")") {
1197 .span_after(mk_sp(last_arg_span.hi, span.hi), ")")
1201 let where_clause_str = match generics {
1203 let budget = context.budget(last_line_width(&header_str));
1204 let shape = Shape::legacy(budget, offset);
1205 let g_span = mk_sp(span.lo, body_lo);
1206 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1207 result.push_str(&generics_str);
1209 let where_budget = context.budget(last_line_width(&result));
1210 try_opt!(rewrite_where_clause(
1212 &generics.where_clause,
1213 context.config.item_brace_style(),
1214 Shape::legacy(where_budget, offset.block_only()),
1215 Density::Compressed,
1224 None => "".to_owned(),
1227 if fields.is_empty() {
1229 let used_width = if result.contains('\n') {
1230 last_line_width(&result) + 3
1232 offset.width() + result.len() + 3
1234 if used_width > context.config.max_width() {
1236 result.push_str(&offset
1237 .block_indent(context.config)
1238 .to_string(context.config))
1241 let snippet = context.snippet(mk_sp(body_lo, context.codemap.span_before(span, ")")));
1242 if snippet.is_empty() {
1244 } else if snippet.trim_right_matches(&[' ', '\t'][..]).ends_with('\n') {
1245 result.push_str(&snippet.trim_right());
1247 result.push_str(&offset.to_string(context.config));
1249 result.push_str(&snippet);
1254 let body = try_opt!(
1258 &fields.iter().map(|field| field).collect::<Vec<_>>()[..],
1260 Shape::legacy(context.budget(last_line_width(&result) + 3), offset),
1261 context.config.fn_call_width(),
1265 result.push_str(&body);
1268 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') &&
1269 (result.contains('\n') ||
1270 offset.block_indent + result.len() + where_clause_str.len() + 1 >
1271 context.config.max_width())
1273 // We need to put the where clause on a new line, but we didn't
1274 // know that earlier, so the where clause will not be indented properly.
1276 result.push_str(&(offset.block_only() + (context.config.tab_spaces() - 1))
1277 .to_string(context.config));
1279 result.push_str(&where_clause_str);
1284 pub fn rewrite_type_alias(
1285 context: &RewriteContext,
1289 generics: &ast::Generics,
1290 vis: &ast::Visibility,
1292 ) -> Option<String> {
1293 let mut result = String::new();
1295 result.push_str(&format_visibility(vis));
1296 result.push_str("type ");
1297 result.push_str(&ident.to_string());
1300 let shape = try_opt!(Shape::indented(indent + result.len(), context.config).sub_width(2));
1301 let g_span = mk_sp(context.codemap.span_after(span, "type"), ty.span.lo);
1302 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1303 result.push_str(&generics_str);
1305 let where_budget = try_opt!(
1309 .checked_sub(last_line_width(&result))
1311 let where_clause_str = try_opt!(rewrite_where_clause(
1313 &generics.where_clause,
1314 context.config.item_brace_style(),
1315 Shape::legacy(where_budget, indent),
1316 context.config.where_density(),
1324 result.push_str(&where_clause_str);
1325 result.push_str(" = ");
1327 let line_width = last_line_width(&result);
1328 // This checked_sub may fail as the extra space after '=' is not taken into account
1329 // In that case the budget is set to 0 which will make ty.rewrite retry on a new line
1330 let budget = context
1333 .checked_sub(indent.width() + line_width + ";".len())
1335 let type_indent = indent + line_width;
1336 // Try to fit the type on the same line
1337 let ty_str = try_opt!(
1338 ty.rewrite(context, Shape::legacy(budget, type_indent))
1340 // The line was too short, try to put the type on the next line
1342 // Remove the space after '='
1344 let type_indent = indent.block_indent(context.config);
1346 result.push_str(&type_indent.to_string(context.config));
1347 let budget = try_opt!(
1351 .checked_sub(type_indent.width() + ";".len())
1353 ty.rewrite(context, Shape::legacy(budget, type_indent))
1356 result.push_str(&ty_str);
1357 result.push_str(";");
1361 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1363 if config.space_before_type_annotation() {
1368 if config.space_after_type_annotation_colon() {
1376 fn rewrite_missing_comment_on_field(
1377 context: &RewriteContext,
1381 result: &mut String,
1382 ) -> Option<String> {
1383 let possibly_comment_snippet = context.snippet(mk_sp(lo, hi));
1384 let newline_index = possibly_comment_snippet.find('\n');
1385 let comment_index = possibly_comment_snippet.find('/');
1386 match (newline_index, comment_index) {
1387 (Some(i), Some(j)) if i > j => result.push(' '),
1390 result.push_str(&shape.indent.to_string(context.config));
1393 let trimmed = possibly_comment_snippet.trim();
1394 if trimmed.is_empty() {
1397 rewrite_comment(trimmed, false, shape, context.config).map(|s| {
1398 format!("{}\n{}", s, shape.indent.to_string(context.config))
1403 pub fn rewrite_struct_field_prefix(
1404 context: &RewriteContext,
1405 field: &ast::StructField,
1407 ) -> Option<String> {
1408 let vis = format_visibility(&field.vis);
1409 let mut attr_str = try_opt!(
1412 .rewrite(context, Shape::indented(shape.indent, context.config))
1414 // Try format missing comments after attributes
1415 let missing_comment = if !field.attrs.is_empty() {
1416 rewrite_missing_comment_on_field(
1419 field.attrs[field.attrs.len() - 1].span.hi,
1422 ).unwrap_or(String::new())
1427 let type_annotation_spacing = type_annotation_spacing(context.config);
1428 Some(match field.ident {
1429 Some(name) => format!(
1435 type_annotation_spacing.0
1437 None => format!("{}{}{}", attr_str, missing_comment, vis),
1441 fn rewrite_struct_field_type(
1442 context: &RewriteContext,
1443 last_line_width: usize,
1444 field: &ast::StructField,
1447 ) -> Option<String> {
1448 let ty_shape = try_opt!(shape.offset_left(last_line_width + spacing.len()));
1451 .rewrite(context, ty_shape)
1452 .map(|ty| format!("{}{}", spacing, ty))
1455 impl Rewrite for ast::StructField {
1456 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1457 rewrite_struct_field(context, self, shape, 0)
1461 pub fn rewrite_struct_field(
1462 context: &RewriteContext,
1463 field: &ast::StructField,
1465 lhs_max_width: usize,
1466 ) -> Option<String> {
1467 if contains_skip(&field.attrs) {
1468 let span = context.snippet(mk_sp(field.attrs[0].span.lo, field.span.hi));
1469 return wrap_str(span, context.config.max_width(), shape);
1472 let type_annotation_spacing = type_annotation_spacing(context.config);
1473 let prefix = try_opt!(rewrite_struct_field_prefix(context, field, shape));
1475 // Try to put everything on a single line.
1476 let last_line_width = last_line_width(&prefix);
1477 let mut spacing = String::from(if field.ident.is_some() {
1478 type_annotation_spacing.1
1482 let lhs_offset = lhs_max_width.checked_sub(last_line_width).unwrap_or(0);
1483 for _ in 0..lhs_offset {
1486 let ty_rewritten = rewrite_struct_field_type(context, last_line_width, field, &spacing, shape);
1487 if let Some(ref ty) = ty_rewritten {
1488 if !ty.contains('\n') {
1489 return Some(prefix + &ty);
1493 // We must use multiline.
1494 let type_offset = shape.indent.block_indent(context.config);
1495 let rewrite_type_in_next_line = || {
1498 .rewrite(context, Shape::indented(type_offset, context.config))
1501 match ty_rewritten {
1502 // If we start from the next line and type fits in a single line, then do so.
1503 Some(ref ty) => match rewrite_type_in_next_line() {
1504 Some(ref new_ty) if !new_ty.contains('\n') => Some(format!(
1507 type_offset.to_string(&context.config),
1510 _ => Some(prefix + &ty),
1513 let ty = try_opt!(rewrite_type_in_next_line());
1517 type_offset.to_string(&context.config),
1524 pub fn rewrite_static(
1526 vis: &ast::Visibility,
1529 mutability: ast::Mutability,
1530 expr_opt: Option<&ptr::P<ast::Expr>>,
1533 context: &RewriteContext,
1534 ) -> Option<String> {
1535 let colon = colon_spaces(
1536 context.config.space_before_type_annotation(),
1537 context.config.space_after_type_annotation_colon(),
1539 let prefix = format!(
1541 format_visibility(vis),
1543 format_mutability(mutability),
1548 let ty_str = try_opt!(ty.rewrite(
1551 Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)
1555 if let Some(expr) = expr_opt {
1556 let lhs = format!("{}{} =", prefix, ty_str);
1558 let remaining_width = context.config.max_width() - offset.block_indent - 1;
1563 Shape::legacy(remaining_width, offset.block_only()),
1565 recover_comment_removed(res, span, context, Shape::indented(offset, context.config))
1567 .map(|s| if s.ends_with(';') { s } else { s + ";" })
1569 Some(format!("{}{};", prefix, ty_str))
1573 pub fn rewrite_associated_type(
1575 ty_opt: Option<&ptr::P<ast::Ty>>,
1576 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1577 context: &RewriteContext,
1579 ) -> Option<String> {
1580 let prefix = format!("type {}", ident);
1582 let type_bounds_str = if let Some(ty_param_bounds) = ty_param_bounds_opt {
1583 let shape = Shape::indented(indent, context.config);
1584 let bounds: &[_] = ty_param_bounds;
1585 let bound_str = try_opt!(
1588 .map(|ty_bound| ty_bound.rewrite(context, shape))
1589 .collect::<Option<Vec<_>>>()
1591 if bounds.len() > 0 {
1592 format!(": {}", join_bounds(context, shape, &bound_str))
1600 if let Some(ty) = ty_opt {
1601 let ty_str = try_opt!(ty.rewrite(
1604 context.config.max_width() - indent.block_indent - prefix.len() - 2,
1605 indent.block_only(),
1608 Some(format!("{}{} = {};", prefix, type_bounds_str, ty_str))
1610 Some(format!("{}{};", prefix, type_bounds_str))
1614 pub fn rewrite_associated_impl_type(
1616 defaultness: ast::Defaultness,
1617 ty_opt: Option<&ptr::P<ast::Ty>>,
1618 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1619 context: &RewriteContext,
1621 ) -> Option<String> {
1622 let result = try_opt!(rewrite_associated_type(
1625 ty_param_bounds_opt,
1631 ast::Defaultness::Default => Some(format!("default {}", result)),
1636 impl Rewrite for ast::FunctionRetTy {
1637 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1639 ast::FunctionRetTy::Default(_) => Some(String::new()),
1640 ast::FunctionRetTy::Ty(ref ty) => {
1641 let inner_width = try_opt!(shape.width.checked_sub(3));
1642 ty.rewrite(context, Shape::legacy(inner_width, shape.indent + 3))
1643 .map(|r| format!("-> {}", r))
1649 fn is_empty_infer(context: &RewriteContext, ty: &ast::Ty) -> bool {
1651 ast::TyKind::Infer => {
1652 let original = context.snippet(ty.span);
1659 impl Rewrite for ast::Arg {
1660 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1661 if is_named_arg(self) {
1662 let mut result = try_opt!(
1664 .rewrite(context, Shape::legacy(shape.width, shape.indent))
1667 if !is_empty_infer(context, &*self.ty) {
1668 if context.config.space_before_type_annotation() {
1669 result.push_str(" ");
1671 result.push_str(":");
1672 if context.config.space_after_type_annotation_colon() {
1673 result.push_str(" ");
1675 let max_width = try_opt!(shape.width.checked_sub(result.len()));
1676 let ty_str = try_opt!(self.ty.rewrite(
1678 Shape::legacy(max_width, shape.indent + result.len()),
1680 result.push_str(&ty_str);
1685 self.ty.rewrite(context, shape)
1690 fn rewrite_explicit_self(
1691 explicit_self: &ast::ExplicitSelf,
1693 context: &RewriteContext,
1694 ) -> Option<String> {
1695 match explicit_self.node {
1696 ast::SelfKind::Region(lt, m) => {
1697 let mut_str = format_mutability(m);
1700 let lifetime_str = try_opt!(l.rewrite(
1702 Shape::legacy(context.config.max_width(), Indent::empty()),
1704 Some(format!("&{} {}self", lifetime_str, mut_str))
1706 None => Some(format!("&{}self", mut_str)),
1709 ast::SelfKind::Explicit(ref ty, _) => {
1710 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1712 let mutability = explicit_self_mutability(&args[0]);
1713 let type_str = try_opt!(ty.rewrite(
1715 Shape::legacy(context.config.max_width(), Indent::empty()),
1720 format_mutability(mutability),
1724 ast::SelfKind::Value(_) => {
1725 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1727 let mutability = explicit_self_mutability(&args[0]);
1729 Some(format!("{}self", format_mutability(mutability)))
1734 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1735 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1736 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1737 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1744 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1745 if is_named_arg(arg) {
1752 pub fn span_hi_for_arg(context: &RewriteContext, arg: &ast::Arg) -> BytePos {
1754 ast::TyKind::Infer if context.snippet(arg.ty.span) == "_" => arg.ty.span.hi,
1755 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi,
1756 _ => arg.ty.span.hi,
1760 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1761 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1762 ident.node != symbol::keywords::Invalid.ident()
1768 // Return type is (result, force_new_line_for_brace)
1770 context: &RewriteContext,
1774 generics: &ast::Generics,
1775 unsafety: ast::Unsafety,
1776 constness: ast::Constness,
1777 defaultness: ast::Defaultness,
1779 vis: &ast::Visibility,
1781 newline_brace: bool,
1784 ) -> Option<(String, bool)> {
1785 let mut force_new_line_for_brace = false;
1787 let where_clause = &generics.where_clause;
1789 let mut result = String::with_capacity(1024);
1790 // Vis unsafety abi.
1791 result.push_str(&*format_visibility(vis));
1793 if let ast::Defaultness::Default = defaultness {
1794 result.push_str("default ");
1797 if let ast::Constness::Const = constness {
1798 result.push_str("const ");
1801 result.push_str(::utils::format_unsafety(unsafety));
1803 if abi != abi::Abi::Rust {
1804 result.push_str(&::utils::format_abi(
1806 context.config.force_explicit_abi(),
1811 result.push_str("fn ");
1812 result.push_str(&ident.to_string());
1815 let overhead = if has_braces && !newline_brace {
1822 let shape = try_opt!(
1823 Shape::indented(indent + last_line_width(&result), context.config).sub_width(overhead)
1825 let g_span = mk_sp(span.lo, fd.output.span().lo);
1826 let generics_str = try_opt!(rewrite_generics(context, generics, shape, g_span));
1827 result.push_str(&generics_str);
1829 let snuggle_angle_bracket = generics_str
1832 .map_or(false, |l| l.trim_left().len() == 1);
1834 // Note that the width and indent don't really matter, we'll re-layout the
1835 // return type later anyway.
1836 let ret_str = try_opt!(
1838 .rewrite(&context, Shape::indented(indent, context.config))
1841 let multi_line_ret_str = ret_str.contains('\n');
1842 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1845 let (mut one_line_budget, mut multi_line_budget, mut arg_indent) =
1846 try_opt!(compute_budgets_for_args(
1855 if context.config.fn_args_layout() == IndentStyle::Block {
1856 arg_indent = indent.block_indent(context.config);
1858 multi_line_budget = context.config.max_width() - (arg_indent.width() + 1);
1862 "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1868 // Check if vertical layout was forced.
1869 if one_line_budget == 0 {
1870 if snuggle_angle_bracket {
1873 if context.config.fn_args_paren_newline() {
1875 result.push_str(&arg_indent.to_string(context.config));
1876 if context.config.fn_args_layout() == IndentStyle::Visual {
1877 arg_indent = arg_indent + 1; // extra space for `(`
1881 result.push_str("(");
1882 if context.config.fn_args_layout() == IndentStyle::Visual {
1884 result.push_str(&arg_indent.to_string(context.config));
1891 if context.config.spaces_within_parens() && fd.inputs.len() > 0 && result.ends_with('(') {
1895 if multi_line_ret_str {
1896 one_line_budget = 0;
1899 // A conservative estimation, to goal is to be over all parens in generics
1900 let args_start = generics
1903 .map_or(span.lo, |tp| end_typaram(tp));
1904 let args_end = if fd.inputs.is_empty() {
1905 context.codemap.span_after(mk_sp(args_start, span.hi), ")")
1907 let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi, span.hi);
1908 context.codemap.span_after(last_span, ")")
1910 let args_span = mk_sp(
1911 context.codemap.span_after(mk_sp(args_start, span.hi), "("),
1914 let arg_str = try_opt!(rewrite_args(
1917 fd.get_self().as_ref(),
1924 generics_str.contains('\n'),
1927 let multi_line_arg_str =
1928 arg_str.contains('\n') || arg_str.chars().last().map_or(false, |c| c == ',');
1930 let put_args_in_block = match context.config.fn_args_layout() {
1931 IndentStyle::Block => multi_line_arg_str || generics_str.contains('\n'),
1933 } && !fd.inputs.is_empty();
1935 let mut args_last_line_contains_comment = false;
1936 if put_args_in_block {
1937 arg_indent = indent.block_indent(context.config);
1939 result.push_str(&arg_indent.to_string(context.config));
1940 result.push_str(&arg_str);
1942 result.push_str(&indent.to_string(context.config));
1945 result.push_str(&arg_str);
1946 if context.config.spaces_within_parens() && fd.inputs.len() > 0 {
1949 // If the last line of args contains comment, we cannot put the closing paren
1950 // on the same line.
1954 .map_or(false, |last_line| last_line.contains("//"))
1956 args_last_line_contains_comment = true;
1958 result.push_str(&arg_indent.to_string(context.config));
1964 if !ret_str.is_empty() {
1965 let ret_should_indent = match context.config.fn_args_layout() {
1966 // If our args are block layout then we surely must have space.
1967 IndentStyle::Block if put_args_in_block => false,
1969 // If we've already gone multi-line, or the return type would push over the max
1970 // width, then put the return type on a new line. With the +1 for the signature
1971 // length an additional space between the closing parenthesis of the argument and
1972 // the arrow '->' is considered.
1973 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1975 // If there is no where clause, take into account the space after the return type
1977 if where_clause.predicates.is_empty() {
1981 let overlong_sig = sig_length > context.config.max_width();
1983 (!args_last_line_contains_comment) &&
1984 (result.contains('\n') || multi_line_ret_str || overlong_sig)
1987 let ret_indent = if ret_should_indent {
1988 let indent = match context.config.fn_return_indent() {
1989 ReturnIndent::WithWhereClause => indent + 4,
1990 // Aligning with non-existent args looks silly.
1991 _ if arg_str.is_empty() => {
1992 force_new_line_for_brace = true;
1995 // FIXME: we might want to check that using the arg indent
1996 // doesn't blow our budget, and if it does, then fallback to
1997 // the where clause indent.
2002 result.push_str(&indent.to_string(context.config));
2006 Indent::new(indent.block_indent, last_line_width(&result))
2009 if multi_line_ret_str || ret_should_indent {
2010 // Now that we know the proper indent and width, we need to
2011 // re-layout the return type.
2012 let ret_str = try_opt!(
2014 .rewrite(context, Shape::indented(ret_indent, context.config))
2016 result.push_str(&ret_str);
2018 result.push_str(&ret_str);
2021 // Comment between return type and the end of the decl.
2022 let snippet_lo = fd.output.span().hi;
2023 if where_clause.predicates.is_empty() {
2024 let snippet_hi = span.hi;
2025 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
2026 // Try to preserve the layout of the original snippet.
2027 let original_starts_with_newline = snippet
2029 .map_or(false, |i| snippet[i..].starts_with('\n'));
2030 let original_ends_with_newline = snippet
2031 .rfind(|c| c != ' ')
2032 .map_or(false, |i| snippet[i..].ends_with('\n'));
2033 let snippet = snippet.trim();
2034 if !snippet.is_empty() {
2035 result.push(if original_starts_with_newline {
2040 result.push_str(snippet);
2041 if original_ends_with_newline {
2042 force_new_line_for_brace = true;
2046 // FIXME it would be nice to catch comments between the return type
2047 // and the where clause, but we don't have a span for the where
2052 let should_compress_where = match context.config.where_density() {
2053 Density::Compressed => !result.contains('\n') || put_args_in_block,
2054 Density::CompressedIfEmpty => !has_body && !result.contains('\n'),
2056 } || (put_args_in_block && ret_str.is_empty());
2058 let pos_before_where = match fd.output {
2059 ast::FunctionRetTy::Default(..) => args_span.hi,
2060 ast::FunctionRetTy::Ty(ref ty) => ty.span.hi,
2062 if where_clause.predicates.len() == 1 && should_compress_where {
2063 let budget = try_opt!(
2067 .checked_sub(last_line_width(&result))
2069 if let Some(where_clause_str) = rewrite_where_clause(
2072 context.config.fn_brace_style(),
2073 Shape::legacy(budget, indent),
2074 Density::Compressed,
2077 put_args_in_block && ret_str.is_empty(),
2082 if !where_clause_str.contains('\n') {
2083 if last_line_width(&result) + where_clause_str.len() > context.config.max_width() {
2087 result.push_str(&where_clause_str);
2089 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2090 return Some((result, force_new_line_for_brace));
2095 let where_clause_str = try_opt!(rewrite_where_clause(
2098 context.config.fn_brace_style(),
2099 Shape::indented(indent, context.config),
2103 put_args_in_block && ret_str.is_empty(),
2109 result.push_str(&where_clause_str);
2111 force_new_line_for_brace |= last_line_contains_single_line_comment(&result);
2112 return Some((result, force_new_line_for_brace));
2115 fn last_line_contains_single_line_comment(s: &str) -> bool {
2116 s.lines().last().map_or(false, |l| l.contains("//"))
2120 context: &RewriteContext,
2122 explicit_self: Option<&ast::ExplicitSelf>,
2123 one_line_budget: usize,
2124 multi_line_budget: usize,
2129 generics_str_contains_newline: bool,
2130 ) -> Option<String> {
2131 let mut arg_item_strs = try_opt!(
2134 arg.rewrite(&context, Shape::legacy(multi_line_budget, arg_indent))
2136 .collect::<Option<Vec<_>>>()
2139 // Account for sugary self.
2140 // FIXME: the comment for the self argument is dropped. This is blocked
2141 // on rust issue #27522.
2142 let min_args = explicit_self
2143 .and_then(|explicit_self| {
2144 rewrite_explicit_self(explicit_self, args, context)
2146 .map_or(1, |self_str| {
2147 arg_item_strs[0] = self_str;
2151 // Comments between args.
2152 let mut arg_items = Vec::new();
2154 arg_items.push(ListItem::from_str(""));
2157 // FIXME(#21): if there are no args, there might still be a comment, but
2158 // without spans for the comment or parens, there is no chance of
2159 // getting it right. You also don't get to put a comment on self, unless
2161 if args.len() >= min_args || variadic {
2162 let comment_span_start = if min_args == 2 {
2163 let second_arg_start = if arg_has_pattern(&args[1]) {
2168 let reduced_span = mk_sp(span.lo, second_arg_start);
2170 context.codemap.span_after_last(reduced_span, ",")
2175 enum ArgumentKind<'a> {
2176 Regular(&'a ast::Arg),
2180 let variadic_arg = if variadic {
2181 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi, span.hi);
2182 let variadic_start = context.codemap.span_after(variadic_span, "...") - BytePos(3);
2183 Some(ArgumentKind::Variadic(variadic_start))
2188 let more_items = itemize_list(
2190 args[min_args - 1..]
2192 .map(ArgumentKind::Regular)
2193 .chain(variadic_arg),
2196 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
2197 ArgumentKind::Variadic(start) => start,
2200 ArgumentKind::Regular(arg) => arg.ty.span.hi,
2201 ArgumentKind::Variadic(start) => start + BytePos(3),
2204 ArgumentKind::Regular(..) => None,
2205 ArgumentKind::Variadic(..) => Some("...".to_owned()),
2211 arg_items.extend(more_items);
2214 let fits_in_one_line = !generics_str_contains_newline &&
2215 (arg_items.len() == 0 || arg_items.len() == 1 && arg_item_strs[0].len() <= one_line_budget);
2217 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
2218 item.item = Some(arg);
2221 let last_line_ends_with_comment = arg_items
2224 .and_then(|item| item.post_comment.as_ref())
2225 .map_or(false, |s| s.trim().starts_with("//"));
2227 let (indent, trailing_comma) = match context.config.fn_args_layout() {
2228 IndentStyle::Block if fits_in_one_line => {
2229 (indent.block_indent(context.config), SeparatorTactic::Never)
2231 IndentStyle::Block => (
2232 indent.block_indent(context.config),
2233 context.config.trailing_comma(),
2235 IndentStyle::Visual if last_line_ends_with_comment => {
2236 (arg_indent, context.config.trailing_comma())
2238 IndentStyle::Visual => (arg_indent, SeparatorTactic::Never),
2241 let tactic = definitive_tactic(
2243 context.config.fn_args_density().to_list_tactic(),
2247 let budget = match tactic {
2248 DefinitiveListTactic::Horizontal => one_line_budget,
2249 _ => multi_line_budget,
2252 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
2254 let fmt = ListFormatting {
2257 trailing_separator: if variadic {
2258 SeparatorTactic::Never
2262 shape: Shape::legacy(budget, indent),
2263 ends_with_newline: tactic.ends_with_newline(context.config.fn_args_layout()),
2264 preserve_newline: true,
2265 config: context.config,
2268 write_list(&arg_items, &fmt)
2271 fn arg_has_pattern(arg: &ast::Arg) -> bool {
2272 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
2273 ident.node != symbol::keywords::Invalid.ident()
2279 fn compute_budgets_for_args(
2280 context: &RewriteContext,
2284 newline_brace: bool,
2286 ) -> Option<((usize, usize, Indent))> {
2288 "compute_budgets_for_args {} {:?}, {}, {}",
2294 // Try keeping everything on the same line.
2295 if !result.contains('\n') {
2296 // 2 = `()`, 3 = `() `, space is before ret_string.
2297 let overhead = if ret_str_len == 0 { 2 } else { 3 };
2298 let mut used_space = indent.width() + result.len() + ret_str_len + overhead;
2308 let one_line_budget = context
2311 .checked_sub(used_space)
2314 if one_line_budget > 0 {
2316 let multi_line_overhead =
2317 indent.width() + result.len() + if newline_brace { 2 } else { 4 };
2318 let multi_line_budget =
2319 try_opt!(context.config.max_width().checked_sub(multi_line_overhead));
2324 indent + result.len() + 1,
2329 // Didn't work. we must force vertical layout and put args on a newline.
2330 let new_indent = indent.block_indent(context.config);
2331 // Account for `)` and possibly ` {`.
2332 let used_space = new_indent.width() + if ret_str_len == 0 { 1 } else { 3 };
2333 let max_space = try_opt!(context.config.max_width().checked_sub(used_space));
2334 Some((0, max_space, new_indent))
2337 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
2338 match config.fn_brace_style() {
2339 BraceStyle::AlwaysNextLine => true,
2340 BraceStyle::SameLineWhere if !where_clause.predicates.is_empty() => true,
2345 fn rewrite_generics(
2346 context: &RewriteContext,
2347 generics: &ast::Generics,
2350 ) -> Option<String> {
2351 let g_shape = try_opt!(generics_shape_from_config(context.config, shape, 0));
2352 let one_line_width = shape.width.checked_sub(2).unwrap_or(0);
2353 rewrite_generics_inner(context, generics, g_shape, one_line_width, span).or_else(|| {
2354 rewrite_generics_inner(context, generics, g_shape, 0, span)
2358 fn rewrite_generics_inner(
2359 context: &RewriteContext,
2360 generics: &ast::Generics,
2362 one_line_width: usize,
2364 ) -> Option<String> {
2365 // FIXME: convert bounds to where clauses where they get too big or if
2366 // there is a where clause at all.
2367 let lifetimes: &[_] = &generics.lifetimes;
2368 let tys: &[_] = &generics.ty_params;
2369 if lifetimes.is_empty() && tys.is_empty() {
2370 return Some(String::new());
2373 // Strings for the generics.
2374 let lt_strs = lifetimes.iter().map(|lt| lt.rewrite(context, shape));
2375 let ty_strs = tys.iter().map(|ty_param| ty_param.rewrite(context, shape));
2377 // Extract comments between generics.
2378 let lt_spans = lifetimes.iter().map(|l| {
2379 let hi = if l.bounds.is_empty() {
2382 l.bounds[l.bounds.len() - 1].span.hi
2384 mk_sp(l.lifetime.span.lo, hi)
2386 let ty_spans = tys.iter().map(|ty| ty.span());
2388 let items = itemize_list(
2390 lt_spans.chain(ty_spans).zip(lt_strs.chain(ty_strs)),
2394 // FIXME: don't clone
2395 |&(_, ref str)| str.clone(),
2396 context.codemap.span_after(span, "<"),
2399 format_generics_item_list(context, items, shape, one_line_width)
2402 pub fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> {
2403 match config.generics_indent() {
2404 IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2),
2405 IndentStyle::Block => {
2409 .block_indent(config.tab_spaces())
2410 .with_max_width(config)
2416 pub fn format_generics_item_list<I>(
2417 context: &RewriteContext,
2420 one_line_budget: usize,
2423 I: Iterator<Item = ListItem>,
2425 let item_vec = items.collect::<Vec<_>>();
2427 let tactic = definitive_tactic(
2429 ListTactic::HorizontalVertical,
2433 let fmt = ListFormatting {
2436 trailing_separator: if context.config.generics_indent() == IndentStyle::Visual {
2437 SeparatorTactic::Never
2439 context.config.trailing_comma()
2442 ends_with_newline: tactic.ends_with_newline(context.config.generics_indent()),
2443 preserve_newline: true,
2444 config: context.config,
2447 let list_str = try_opt!(write_list(&item_vec, &fmt));
2449 Some(wrap_generics_with_angle_brackets(
2456 pub fn wrap_generics_with_angle_brackets(
2457 context: &RewriteContext,
2459 list_offset: Indent,
2461 if context.config.generics_indent() == IndentStyle::Block &&
2462 (list_str.contains('\n') || list_str.ends_with(','))
2466 list_offset.to_string(context.config),
2469 .block_unindent(context.config)
2470 .to_string(context.config)
2472 } else if context.config.spaces_within_angle_brackets() {
2473 format!("< {} >", list_str)
2475 format!("<{}>", list_str)
2479 fn rewrite_trait_bounds(
2480 context: &RewriteContext,
2481 type_param_bounds: &ast::TyParamBounds,
2483 ) -> Option<String> {
2484 let bounds: &[_] = type_param_bounds;
2486 if bounds.is_empty() {
2487 return Some(String::new());
2489 let bound_str = try_opt!(
2492 .map(|ty_bound| ty_bound.rewrite(&context, shape))
2493 .collect::<Option<Vec<_>>>()
2495 Some(format!(": {}", join_bounds(context, shape, &bound_str)))
2498 fn rewrite_where_clause_rfc_style(
2499 context: &RewriteContext,
2500 where_clause: &ast::WhereClause,
2503 suppress_comma: bool,
2504 // where clause can be kept on the current line.
2506 span_end: Option<BytePos>,
2508 span_end_before_where: BytePos,
2509 ) -> Option<String> {
2510 let block_shape = shape.block().with_max_width(context.config);
2512 let (span_before, span_after) =
2513 missing_span_before_after_where(context, span.hi, span_end_before_where, where_clause);
2514 let (comment_before, comment_after) = try_opt!(rewrite_comments_before_after_where(
2521 let starting_newline = if snuggle && comment_before.is_empty() {
2524 "\n".to_owned() + &block_shape.indent.to_string(context.config)
2527 let clause_shape = block_shape.block_indent(context.config.tab_spaces());
2528 // each clause on one line, trailing comma (except if suppress_comma)
2529 let span_start = where_clause.predicates[0].span().lo;
2530 // If we don't have the start of the next span, then use the end of the
2531 // predicates, but that means we miss comments.
2532 let len = where_clause.predicates.len();
2533 let end_of_preds = where_clause.predicates[len - 1].span().hi;
2534 let span_end = span_end.unwrap_or(end_of_preds);
2535 let items = itemize_list(
2537 where_clause.predicates.iter(),
2539 |pred| pred.span().lo,
2540 |pred| pred.span().hi,
2541 |pred| pred.rewrite(context, block_shape),
2545 let comma_tactic = if suppress_comma {
2546 SeparatorTactic::Never
2548 context.config.trailing_comma()
2551 let fmt = ListFormatting {
2552 tactic: DefinitiveListTactic::Vertical,
2554 trailing_separator: comma_tactic,
2555 shape: clause_shape,
2556 ends_with_newline: true,
2557 preserve_newline: true,
2558 config: context.config,
2560 let preds_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
2562 let newline_before_where = if comment_before.is_empty() || comment_before.ends_with('\n') {
2565 "\n".to_owned() + &shape.indent.to_string(context.config)
2567 let newline_after_where = if comment_after.is_empty() {
2570 "\n".to_owned() + &clause_shape.indent.to_string(context.config)
2573 "{}{}{}where{}{}\n{}{}",
2576 newline_before_where,
2577 newline_after_where,
2579 clause_shape.indent.to_string(context.config),
2584 fn rewrite_where_clause(
2585 context: &RewriteContext,
2586 where_clause: &ast::WhereClause,
2587 brace_style: BraceStyle,
2591 suppress_comma: bool,
2593 span_end: Option<BytePos>,
2595 span_end_before_where: BytePos,
2596 ) -> Option<String> {
2597 if where_clause.predicates.is_empty() {
2598 return Some(String::new());
2601 if context.config.where_style() == Style::Rfc {
2602 return rewrite_where_clause_rfc_style(
2611 span_end_before_where,
2615 let extra_indent = Indent::new(context.config.tab_spaces(), 0);
2617 let offset = match context.config.where_pred_indent() {
2618 IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config),
2619 // 6 = "where ".len()
2620 IndentStyle::Visual => shape.indent + extra_indent + 6,
2622 // FIXME: if where_pred_indent != Visual, then the budgets below might
2623 // be out by a char or two.
2625 let budget = context.config.max_width() - offset.width();
2626 let span_start = where_clause.predicates[0].span().lo;
2627 // If we don't have the start of the next span, then use the end of the
2628 // predicates, but that means we miss comments.
2629 let len = where_clause.predicates.len();
2630 let end_of_preds = where_clause.predicates[len - 1].span().hi;
2631 let span_end = span_end.unwrap_or(end_of_preds);
2632 let items = itemize_list(
2634 where_clause.predicates.iter(),
2636 |pred| pred.span().lo,
2637 |pred| pred.span().hi,
2638 |pred| pred.rewrite(context, Shape::legacy(budget, offset)),
2642 let item_vec = items.collect::<Vec<_>>();
2643 // FIXME: we don't need to collect here if the where_layout isn't
2644 // HorizontalVertical.
2645 let tactic = definitive_tactic(&item_vec, context.config.where_layout(), 2, budget);
2647 let mut comma_tactic = context.config.trailing_comma();
2648 // Kind of a hack because we don't usually have trailing commas in where clauses.
2649 if comma_tactic == SeparatorTactic::Vertical || suppress_comma {
2650 comma_tactic = SeparatorTactic::Never;
2653 let fmt = ListFormatting {
2656 trailing_separator: comma_tactic,
2657 shape: Shape::legacy(budget, offset),
2658 ends_with_newline: tactic.ends_with_newline(context.config.where_pred_indent()),
2659 preserve_newline: true,
2660 config: context.config,
2662 let preds_str = try_opt!(write_list(&item_vec, &fmt));
2664 let end_length = if terminator == "{" {
2665 // If the brace is on the next line we don't need to count it otherwise it needs two
2668 BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0,
2669 BraceStyle::PreferSameLine => 2,
2671 } else if terminator == "=" {
2676 if density == Density::Tall || preds_str.contains('\n') ||
2677 shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width
2681 (shape.indent + extra_indent).to_string(context.config),
2685 Some(format!(" where {}", preds_str))
2689 fn missing_span_before_after_where(
2690 context: &RewriteContext,
2692 before_item_span_end: BytePos,
2693 where_clause: &ast::WhereClause,
2695 let snippet = context.snippet(mk_sp(before_item_span_end, item_end));
2696 let pos_before_where =
2697 before_item_span_end + BytePos(snippet.find_uncommented("where").unwrap() as u32);
2698 let missing_span_before = mk_sp(before_item_span_end, pos_before_where);
2700 let pos_after_where = pos_before_where + BytePos(5);
2701 let missing_span_after = mk_sp(pos_after_where, where_clause.predicates[0].span().lo);
2702 (missing_span_before, missing_span_after)
2705 fn rewrite_missing_comment_in_where(
2706 context: &RewriteContext,
2709 ) -> Option<String> {
2710 let comment = comment.trim();
2711 if comment.is_empty() {
2714 rewrite_comment(comment, false, shape, context.config)
2718 fn rewrite_comments_before_after_where(
2719 context: &RewriteContext,
2720 span_before_where: Span,
2721 span_after_where: Span,
2723 ) -> Option<(String, String)> {
2724 let before_comment = try_opt!(rewrite_missing_comment_in_where(
2726 &context.snippet(span_before_where),
2729 let after_comment = try_opt!(rewrite_missing_comment_in_where(
2731 &context.snippet(span_after_where),
2732 shape.block_indent(context.config.tab_spaces()),
2734 Some((before_comment, after_comment))
2737 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
2738 format!("{}{}{}", format_visibility(vis), item_name, ident)
2742 context: &RewriteContext,
2743 generics: &ast::Generics,
2746 brace_style: BraceStyle,
2747 force_same_line_brace: bool,
2751 ) -> Option<String> {
2752 let shape = Shape::legacy(context.budget(used_width + offset.width()), offset);
2753 let mut result = try_opt!(rewrite_generics(context, generics, shape, span));
2755 let same_line_brace = if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
2756 let budget = context
2759 .checked_sub(last_line_width(&result))
2761 let where_clause_str = try_opt!(rewrite_where_clause(
2763 &generics.where_clause,
2765 Shape::legacy(budget, offset.block_only()),
2769 trimmed_last_line_width(&result) == 1,
2774 result.push_str(&where_clause_str);
2775 force_same_line_brace || brace_style == BraceStyle::PreferSameLine ||
2776 (generics.where_clause.predicates.is_empty() && trimmed_last_line_width(&result) == 1)
2778 force_same_line_brace || trimmed_last_line_width(&result) == 1 ||
2779 brace_style != BraceStyle::AlwaysNextLine
2781 let total_used_width = if result.contains('\n') {
2782 last_line_width(&result)
2784 used_width + result.len()
2786 let remaining_budget = context
2789 .checked_sub(total_used_width)
2791 // If the same line brace if forced, it indicates that we are rewriting an item with empty body,
2792 // and hence we take the closer into account as well for one line budget.
2793 // We assume that the closer has the same length as the opener.
2794 let overhead = if force_same_line_brace {
2795 1 + opener.len() + opener.len()
2799 let forbid_same_line_brace = overhead > remaining_budget;
2800 if !forbid_same_line_brace && same_line_brace {
2804 result.push_str(&offset.block_only().to_string(context.config));
2806 result.push_str(opener);