1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // Formatting top-level items - functions, structs, enums, traits, impls.
14 use 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 use lists::{write_list, itemize_list, ListItem, ListFormatting, SeparatorTactic,
18 DefinitiveListTactic, ListTactic, definitive_tactic, format_item_list};
19 use expr::{is_empty_block, is_simple_block_stmt, rewrite_assign_rhs, type_annotation_separator};
20 use comment::{FindUncommented, contains_comment};
21 use visitor::FmtVisitor;
22 use rewrite::{Rewrite, RewriteContext};
23 use config::{Config, BlockIndentStyle, Density, ReturnIndent, BraceStyle, FnArgLayoutStyle};
24 use itertools::Itertools;
26 use syntax::{ast, abi, ptr, codemap};
27 use syntax::codemap::{Span, BytePos, mk_sp};
28 use syntax::parse::token;
29 use syntax::ast::ImplItem;
31 // Statements of the form
32 // let pat: ty = init;
33 impl Rewrite for ast::Local {
34 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
35 let mut result = "let ".to_owned();
36 let pattern_offset = offset + result.len();
38 let pattern_width = try_opt!(width.checked_sub(pattern_offset.width() + 1));
40 let pat_str = try_opt!(self.pat.rewrite(&context, pattern_width, pattern_offset));
41 result.push_str(&pat_str);
43 // String that is placed within the assignment pattern and expression.
45 let mut infix = String::new();
47 if let Some(ref ty) = self.ty {
48 let separator = type_annotation_separator(context.config);
49 let indent = offset + last_line_width(&result) + separator.len();
51 let budget = try_opt!(width.checked_sub(indent.width() + 1));
52 let rewrite = try_opt!(ty.rewrite(context, budget, indent));
54 infix.push_str(separator);
55 infix.push_str(&rewrite);
58 if self.init.is_some() {
65 result.push_str(&infix);
67 if let Some(ref ex) = self.init {
68 let budget = try_opt!(width.checked_sub(context.block_indent.width() + 1));
70 // 1 = trailing semicolon;
72 try_opt!(rewrite_assign_rhs(&context, result, ex, budget, context.block_indent));
80 impl<'a> FmtVisitor<'a> {
81 pub fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) {
82 let abi_str = ::utils::format_abi(fm.abi, self.config.force_explicit_abi);
83 self.buffer.push_str(&abi_str);
85 let snippet = self.snippet(span);
86 let brace_pos = snippet.find_uncommented("{").unwrap();
88 self.buffer.push_str("{");
89 if !fm.items.is_empty() || contains_comment(&snippet[brace_pos..]) {
90 // FIXME: this skips comments between the extern keyword and the opening
92 self.last_pos = span.lo + BytePos(brace_pos as u32 + 1);
93 self.block_indent = self.block_indent.block_indent(self.config);
95 if fm.items.is_empty() {
96 self.format_missing_no_indent(span.hi - BytePos(1));
97 self.block_indent = self.block_indent.block_unindent(self.config);
99 self.buffer.push_str(&self.block_indent.to_string(self.config));
101 for item in &fm.items {
102 self.format_foreign_item(&*item);
105 self.block_indent = self.block_indent.block_unindent(self.config);
106 self.format_missing_with_indent(span.hi - BytePos(1));
110 self.buffer.push_str("}");
111 self.last_pos = span.hi;
114 fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
115 self.format_missing_with_indent(item.span.lo);
116 // Drop semicolon or it will be interpreted as comment.
117 // FIXME: this may be a faulty span from libsyntax.
118 let span = mk_sp(item.span.lo, item.span.hi - BytePos(1));
121 ast::ForeignItemKind::Fn(ref fn_decl, ref generics) => {
122 let indent = self.block_indent;
123 let rewrite = rewrite_fn_base(&self.get_context(),
128 ast::Unsafety::Normal,
129 ast::Constness::NotConst,
130 ast::Defaultness::Final,
131 // These are not actually rust functions,
132 // but we format them as such.
140 Some((new_fn, _)) => {
141 self.buffer.push_str(&new_fn);
142 self.buffer.push_str(";");
144 None => self.format_missing(item.span.hi),
147 ast::ForeignItemKind::Static(ref ty, is_mutable) => {
148 // FIXME(#21): we're dropping potential comments in between the
149 // function keywords here.
150 let vis = format_visibility(&item.vis);
151 let mut_str = if is_mutable { "mut " } else { "" };
152 let prefix = format!("{}static {}{}: ", vis, mut_str, item.ident);
153 let offset = self.block_indent + prefix.len();
155 let width = self.config.max_width - offset.width() - 1;
156 let rewrite = ty.rewrite(&self.get_context(), width, offset);
160 self.buffer.push_str(&prefix);
161 self.buffer.push_str(&result);
162 self.buffer.push_str(";");
164 None => self.format_missing(item.span.hi),
169 self.last_pos = item.span.hi;
172 pub fn rewrite_fn(&mut self,
176 generics: &ast::Generics,
177 unsafety: ast::Unsafety,
178 constness: ast::Constness,
179 defaultness: ast::Defaultness,
181 vis: &ast::Visibility,
185 let mut newline_brace = newline_for_brace(self.config, &generics.where_clause);
186 let context = self.get_context();
188 let block_snippet = self.snippet(codemap::mk_sp(block.span.lo, block.span.hi));
189 let has_body = !block_snippet[1..block_snippet.len() - 1].trim().is_empty() ||
190 !context.config.fn_empty_single_line;
192 let (mut result, force_newline_brace) = try_opt!(rewrite_fn_base(&context,
206 if self.config.fn_brace_style != BraceStyle::AlwaysNextLine && !result.contains('\n') {
207 newline_brace = false;
208 } else if force_newline_brace {
209 newline_brace = true;
212 // Prepare for the function body by possibly adding a newline and
214 // FIXME we'll miss anything between the end of the signature and the
215 // start of the body, but we need more spans from the compiler to solve
219 result.push_str(&indent.to_string(self.config));
224 self.single_line_fn(&result, block).or_else(|| Some(result))
227 pub fn rewrite_required_fn(&mut self,
230 sig: &ast::MethodSig,
233 // Drop semicolon or it will be interpreted as comment.
234 let span = mk_sp(span.lo, span.hi - BytePos(1));
235 let context = self.get_context();
237 let (mut result, _) = try_opt!(rewrite_fn_base(&context,
244 ast::Defaultness::Final,
246 &ast::Visibility::Inherited,
251 // Re-attach semicolon
257 fn single_line_fn(&self, fn_str: &str, block: &ast::Block) -> Option<String> {
258 if fn_str.contains('\n') {
262 let codemap = self.get_context().codemap;
264 if self.config.fn_empty_single_line && is_empty_block(block, codemap) &&
265 self.block_indent.width() + fn_str.len() + 2 <= self.config.max_width {
266 return Some(format!("{}{{}}", fn_str));
269 if self.config.fn_single_line && is_simple_block_stmt(block, codemap) {
271 if let Some(ref stmt) = block.stmts.first() {
272 match stmt_expr(stmt) {
274 let suffix = if semicolon_for_expr(e) { ";" } else { "" };
276 e.rewrite(&self.get_context(),
277 self.config.max_width - self.block_indent.width(),
280 .or_else(|| Some(self.snippet(e.span)))
283 stmt.rewrite(&self.get_context(),
284 self.config.max_width - self.block_indent.width(),
293 if let Some(res) = rewrite {
294 let width = self.block_indent.width() + fn_str.len() + res.len() + 4;
295 if !res.contains('\n') && width <= self.config.max_width {
296 return Some(format!("{}{{ {} }}", fn_str, res));
304 pub fn visit_enum(&mut self,
306 vis: &ast::Visibility,
307 enum_def: &ast::EnumDef,
308 generics: &ast::Generics,
310 self.buffer.push_str(&format_header("enum ", ident, vis));
312 let enum_snippet = self.snippet(span);
313 let brace_pos = enum_snippet.find_uncommented("{").unwrap();
314 let body_start = span.lo + BytePos(brace_pos as u32 + 1);
315 let generics_str = format_generics(&self.get_context(),
319 self.config.item_brace_style,
320 enum_def.variants.is_empty(),
322 self.block_indent.block_indent(self.config),
323 mk_sp(span.lo, body_start))
325 self.buffer.push_str(&generics_str);
327 self.last_pos = body_start;
329 self.block_indent = self.block_indent.block_indent(self.config);
330 let variant_list = self.format_variant_list(enum_def, body_start, span.hi - BytePos(1));
332 Some(ref body_str) => self.buffer.push_str(body_str),
334 if contains_comment(&enum_snippet[brace_pos..]) {
335 self.format_missing_no_indent(span.hi - BytePos(1))
337 self.format_missing(span.hi - BytePos(1))
341 self.block_indent = self.block_indent.block_unindent(self.config);
343 if variant_list.is_some() || contains_comment(&enum_snippet[brace_pos..]) {
344 self.buffer.push_str(&self.block_indent.to_string(self.config));
346 self.buffer.push_str("}");
347 self.last_pos = span.hi;
350 // Format the body of an enum definition
351 fn format_variant_list(&self,
352 enum_def: &ast::EnumDef,
356 if enum_def.variants.is_empty() {
359 let mut result = String::with_capacity(1024);
361 let indentation = self.block_indent.to_string(self.config);
362 result.push_str(&indentation);
364 let items = itemize_list(self.codemap,
365 enum_def.variants.iter(),
368 if !f.node.attrs.is_empty() {
369 f.node.attrs[0].span.lo
375 |f| self.format_variant(f),
379 let budget = self.config.max_width - self.block_indent.width() - 2;
380 let fmt = ListFormatting {
381 tactic: DefinitiveListTactic::Vertical,
383 trailing_separator: SeparatorTactic::from_bool(self.config.enum_trailing_comma),
384 indent: self.block_indent,
386 ends_with_newline: true,
390 let list = try_opt!(write_list(items, &fmt));
391 result.push_str(&list);
396 // Variant of an enum.
397 fn format_variant(&self, field: &ast::Variant) -> Option<String> {
398 if contains_skip(&field.node.attrs) {
399 let lo = field.node.attrs[0].span.lo;
400 let span = mk_sp(lo, field.span.hi);
401 return Some(self.snippet(span));
404 let indent = self.block_indent;
405 let mut result = try_opt!(field.node
407 .rewrite(&self.get_context(),
408 self.config.max_width - indent.width(),
410 if !result.is_empty() {
412 result.push_str(&indent.to_string(self.config));
415 let context = self.get_context();
416 let variant_body = match field.node.data {
417 ast::VariantData::Tuple(..) |
418 ast::VariantData::Struct(..) => {
419 // FIXME: Should limit the width, as we have a trailing comma
420 format_struct(&context,
423 &ast::Visibility::Inherited,
428 Some(self.config.struct_variant_width))
430 ast::VariantData::Unit(..) => {
431 let tag = if let Some(ref expr) = field.node.disr_expr {
432 format!("{} = {}", field.node.name, self.snippet(expr.span))
434 field.node.name.to_string()
438 self.config.max_width,
439 self.config.max_width - indent.width(),
444 if let Some(variant_str) = variant_body {
445 result.push_str(&variant_str);
453 pub fn format_impl(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
454 if let ast::ItemKind::Impl(_, _, ref generics, ref trait_ref, _, ref items) = item.node {
455 let mut result = String::new();
457 // First try to format the ref and type without a split at the 'for'.
458 let mut ref_and_type = try_opt!(format_impl_ref_and_type(context, item, offset, false));
460 // If there is a line break present in the first result format it again
461 // with a split at the 'for'. Skip this if there is no trait ref and
462 // therefore no 'for'.
463 if let Some(_) = *trait_ref {
464 if ref_and_type.contains('\n') {
465 ref_and_type = try_opt!(format_impl_ref_and_type(context, item, offset, true));
468 result.push_str(&ref_and_type);
470 let where_budget = try_opt!(context.config.max_width.checked_sub(last_line_width(&result)));
471 let where_clause_str = try_opt!(rewrite_where_clause(context,
472 &generics.where_clause,
474 context.config.item_brace_style,
475 context.block_indent,
477 context.config.where_density,
482 if try_opt!(is_impl_single_line(context, &items, &result, &where_clause_str, &item)) {
483 result.push_str(&where_clause_str);
484 if where_clause_str.contains('\n') {
485 let white_space = offset.to_string(context.config);
486 result.push_str(&format!("\n{}{{\n{}}}", &white_space, &white_space));
488 result.push_str(" {}");
493 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') {
495 let width = context.block_indent.width() + context.config.tab_spaces - 1;
496 let where_indent = Indent::new(0, width);
497 result.push_str(&where_indent.to_string(context.config));
499 result.push_str(&where_clause_str);
501 match context.config.item_brace_style {
502 BraceStyle::AlwaysNextLine => result.push('\n'),
503 BraceStyle::PreferSameLine => result.push(' '),
504 BraceStyle::SameLineWhere => {
505 if !where_clause_str.is_empty() {
507 result.push_str(&offset.to_string(context.config));
516 let snippet = context.snippet(item.span);
517 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
519 if !items.is_empty() || contains_comment(&snippet[open_pos..]) {
520 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
521 visitor.block_indent = context.block_indent.block_indent(context.config);
522 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
525 visitor.visit_impl_item(item);
528 visitor.format_missing(item.span.hi - BytePos(1));
530 let inner_indent_str = visitor.block_indent.to_string(context.config);
531 let outer_indent_str = context.block_indent.to_string(context.config);
534 result.push_str(&inner_indent_str);
535 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
537 result.push_str(&outer_indent_str);
540 if result.chars().last().unwrap() == '{' {
551 fn is_impl_single_line(context: &RewriteContext,
554 where_clause_str: &str,
557 let snippet = context.snippet(item.span);
558 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
560 Some(context.config.impl_empty_single_line && items.is_empty() &&
561 result.len() + where_clause_str.len() <= context.config.max_width &&
562 !contains_comment(&snippet[open_pos..]))
565 fn format_impl_ref_and_type(context: &RewriteContext,
570 if let ast::ItemKind::Impl(unsafety, polarity, ref generics, ref trait_ref, ref self_ty, _) =
572 let mut result = String::new();
574 result.push_str(&*format_visibility(&item.vis));
575 result.push_str(format_unsafety(unsafety));
576 result.push_str("impl");
578 let lo = context.codemap.span_after(item.span, "impl");
579 let hi = match *trait_ref {
580 Some(ref tr) => tr.path.span.lo,
581 None => self_ty.span.lo,
583 let generics_str = try_opt!(rewrite_generics(context,
586 context.config.max_width,
587 offset + result.len(),
589 result.push_str(&generics_str);
592 if polarity == ast::ImplPolarity::Negative {
595 if let Some(ref trait_ref) = *trait_ref {
596 let budget = try_opt!(context.config.max_width.checked_sub(result.len()));
597 let indent = offset + result.len();
598 result.push_str(&*try_opt!(trait_ref.rewrite(context, budget, indent)));
603 // Add indentation of one additional tab.
604 let width = context.block_indent.width() + context.config.tab_spaces;
605 let for_indent = Indent::new(0, width);
606 result.push_str(&for_indent.to_string(context.config));
608 result.push_str("for ");
610 result.push_str(" for ");
614 let mut used_space = last_line_width(&result);
615 if generics.where_clause.predicates.is_empty() {
616 // If there is no where clause adapt budget for type formatting to take space and curly
617 // brace into account.
618 match context.config.item_brace_style {
619 BraceStyle::AlwaysNextLine => {}
620 BraceStyle::PreferSameLine => used_space += 2,
621 BraceStyle::SameLineWhere => used_space += 2,
625 let budget = try_opt!(context.config.max_width.checked_sub(used_space));
626 let indent = offset + result.len();
627 result.push_str(&*try_opt!(self_ty.rewrite(context, budget, indent)));
635 pub fn format_struct(context: &RewriteContext,
638 vis: &ast::Visibility,
639 struct_def: &ast::VariantData,
640 generics: Option<&ast::Generics>,
643 one_line_width: Option<usize>)
646 ast::VariantData::Unit(..) => Some(format_unit_struct(item_name, ident, vis)),
647 ast::VariantData::Tuple(ref fields, _) => {
648 format_tuple_struct(context,
657 ast::VariantData::Struct(ref fields, _) => {
658 format_struct_struct(context,
671 pub fn format_trait(context: &RewriteContext, item: &ast::Item, offset: Indent) -> Option<String> {
672 if let ast::ItemKind::Trait(unsafety, ref generics, ref type_param_bounds, ref trait_items) =
674 let mut result = String::new();
675 let header = format!("{}{}trait {}",
676 format_visibility(&item.vis),
677 format_unsafety(unsafety),
680 result.push_str(&header);
682 let body_lo = context.codemap.span_after(item.span, "{");
684 let generics_str = try_opt!(rewrite_generics(context,
687 context.config.max_width,
688 offset + result.len(),
689 mk_sp(item.span.lo, body_lo)));
690 result.push_str(&generics_str);
692 let trait_bound_str = try_opt!(rewrite_trait_bounds(context,
695 context.config.max_width));
696 // If the trait, generics, and trait bound cannot fit on the same line,
697 // put the trait bounds on an indented new line
698 if offset.width() + last_line_width(&result) + trait_bound_str.len() >
699 context.config.ideal_width {
701 let width = context.block_indent.width() + context.config.tab_spaces;
702 let trait_indent = Indent::new(0, width);
703 result.push_str(&trait_indent.to_string(context.config));
705 result.push_str(&trait_bound_str);
707 let has_body = !trait_items.is_empty();
710 if (context.config.where_density == Density::Compressed &&
711 (!result.contains('\n') ||
712 context.config.fn_args_layout == FnArgLayoutStyle::Block)) ||
713 (context.config.fn_args_layout == FnArgLayoutStyle::Block && result.is_empty()) ||
714 (context.config.where_density == Density::CompressedIfEmpty && !has_body &&
715 !result.contains('\n')) {
721 let where_budget = try_opt!(context.config
723 .checked_sub(last_line_width(&result)));
724 let where_clause_str = try_opt!(rewrite_where_clause(context,
725 &generics.where_clause,
727 context.config.item_brace_style,
728 context.block_indent,
734 // If the where clause cannot fit on the same line,
735 // put the where clause on a new line
736 if !where_clause_str.contains('\n') &&
737 last_line_width(&result) + where_clause_str.len() + offset.width() >
738 context.config.ideal_width {
740 let width = context.block_indent.width() + context.config.tab_spaces - 1;
741 let where_indent = Indent::new(0, width);
742 result.push_str(&where_indent.to_string(context.config));
744 result.push_str(&where_clause_str);
746 match context.config.item_brace_style {
747 BraceStyle::AlwaysNextLine => {
749 result.push_str(&offset.to_string(context.config));
751 BraceStyle::PreferSameLine => result.push(' '),
752 BraceStyle::SameLineWhere => {
753 if !where_clause_str.is_empty() &&
754 (!trait_items.is_empty() || result.contains('\n')) {
756 result.push_str(&offset.to_string(context.config));
764 let snippet = context.snippet(item.span);
765 let open_pos = try_opt!(snippet.find_uncommented("{")) + 1;
767 if !trait_items.is_empty() || contains_comment(&snippet[open_pos..]) {
768 let mut visitor = FmtVisitor::from_codemap(context.parse_session, context.config);
769 visitor.block_indent = context.block_indent.block_indent(context.config);
770 visitor.last_pos = item.span.lo + BytePos(open_pos as u32);
772 for item in trait_items {
773 visitor.visit_trait_item(item);
776 visitor.format_missing(item.span.hi - BytePos(1));
778 let inner_indent_str = visitor.block_indent.to_string(context.config);
779 let outer_indent_str = context.block_indent.to_string(context.config);
782 result.push_str(&inner_indent_str);
783 result.push_str(trim_newlines(visitor.buffer.to_string().trim()));
785 result.push_str(&outer_indent_str);
786 } else if result.contains('\n') {
797 fn format_unit_struct(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
798 format!("{};", format_header(item_name, ident, vis))
801 fn format_struct_struct(context: &RewriteContext,
804 vis: &ast::Visibility,
805 fields: &[ast::StructField],
806 generics: Option<&ast::Generics>,
809 one_line_width: Option<usize>)
811 let mut result = String::with_capacity(1024);
813 let header_str = format_header(item_name, ident, vis);
814 result.push_str(&header_str);
816 let body_lo = context.codemap.span_after(span, "{");
818 let generics_str = match generics {
820 try_opt!(format_generics(context,
824 context.config.item_brace_style,
827 offset + header_str.len(),
828 mk_sp(span.lo, body_lo)))
831 if context.config.item_brace_style == BraceStyle::AlwaysNextLine && !fields.is_empty() {
832 format!("\n{}{{", context.block_indent.to_string(context.config))
838 result.push_str(&generics_str);
840 // FIXME(#919): properly format empty structs and their comments.
841 if fields.is_empty() {
842 result.push_str(&context.snippet(mk_sp(body_lo, span.hi)));
846 let item_indent = offset.block_indent(context.config);
848 let item_budget = try_opt!(context.config.max_width.checked_sub(item_indent.width() + 1));
850 let items = itemize_list(context.codemap,
854 // Include attributes and doc comments, if present
855 if !field.attrs.is_empty() {
856 field.attrs[0].span.lo
861 |field| field.ty.span.hi,
862 |field| field.rewrite(context, item_budget, item_indent),
863 context.codemap.span_after(span, "{"),
865 .collect::<Vec<_>>();
867 let budget = context.config.max_width - offset.width() + context.config.tab_spaces - 1;
869 let tactic = match one_line_width {
870 Some(w) => definitive_tactic(&items, ListTactic::LimitedHorizontalVertical(w), budget),
871 None => DefinitiveListTactic::Vertical,
874 let fmt = ListFormatting {
877 trailing_separator: context.config.struct_trailing_comma,
880 ends_with_newline: true,
881 config: context.config,
883 let items_str = try_opt!(write_list(&items, &fmt));
884 if one_line_width.is_some() && !items_str.contains('\n') {
885 Some(format!("{} {} }}", result, items_str))
887 Some(format!("{}\n{}{}\n{}}}",
889 offset.block_indent(context.config).to_string(context.config),
891 offset.to_string(context.config)))
895 fn format_tuple_struct(context: &RewriteContext,
898 vis: &ast::Visibility,
899 fields: &[ast::StructField],
900 generics: Option<&ast::Generics>,
904 let mut result = String::with_capacity(1024);
906 let header_str = format_header(item_name, ident, vis);
907 result.push_str(&header_str);
909 // FIXME(#919): don't lose comments on empty tuple structs.
910 let body_lo = if fields.is_empty() {
916 let where_clause_str = match generics {
918 let generics_str = try_opt!(rewrite_generics(context,
921 context.config.max_width,
922 offset + header_str.len(),
923 mk_sp(span.lo, body_lo)));
924 result.push_str(&generics_str);
926 let where_budget = try_opt!(context.config
928 .checked_sub(last_line_width(&result)));
929 try_opt!(rewrite_where_clause(context,
930 &generics.where_clause,
932 context.config.item_brace_style,
933 context.block_indent,
940 None => "".to_owned(),
944 let item_indent = context.block_indent + result.len();
946 let item_budget = try_opt!(context.config.max_width.checked_sub(item_indent.width() + 2));
948 let items = itemize_list(context.codemap,
952 // Include attributes and doc comments, if present
953 if !field.attrs.is_empty() {
954 field.attrs[0].span.lo
959 |field| field.ty.span.hi,
960 |field| field.rewrite(context, item_budget, item_indent),
961 context.codemap.span_after(span, "("),
963 let body = try_opt!(format_item_list(items, item_budget, item_indent, context.config));
964 result.push_str(&body);
967 if !where_clause_str.is_empty() && !where_clause_str.contains('\n') &&
968 (result.contains('\n') ||
969 context.block_indent.width() + result.len() + where_clause_str.len() + 1 >
970 context.config.max_width) {
971 // We need to put the where clause on a new line, but we didn'to_string
972 // know that earlier, so the where clause will not be indented properly.
974 result.push_str(&(context.block_indent + (context.config.tab_spaces - 1))
975 .to_string(context.config));
977 result.push_str(&where_clause_str);
982 pub fn rewrite_type_alias(context: &RewriteContext,
986 generics: &ast::Generics,
987 vis: &ast::Visibility,
990 let mut result = String::new();
992 result.push_str(&format_visibility(vis));
993 result.push_str("type ");
994 result.push_str(&ident.to_string());
996 let generics_indent = indent + result.len();
997 let generics_span = mk_sp(context.codemap.span_after(span, "type"), ty.span.lo);
998 let generics_width = context.config.max_width - " =".len();
999 let generics_str = try_opt!(rewrite_generics(context,
1006 result.push_str(&generics_str);
1008 let where_budget = try_opt!(context.config
1010 .checked_sub(last_line_width(&result)));
1011 let where_clause_str = try_opt!(rewrite_where_clause(context,
1012 &generics.where_clause,
1014 context.config.item_brace_style,
1017 context.config.where_density,
1021 result.push_str(&where_clause_str);
1022 result.push_str(" = ");
1024 let line_width = last_line_width(&result);
1025 // This checked_sub may fail as the extra space after '=' is not taken into account
1026 // In that case the budget is set to 0 which will make ty.rewrite retry on a new line
1027 let budget = context.config
1029 .checked_sub(indent.width() + line_width + ";".len())
1031 let type_indent = indent + line_width;
1032 // Try to fit the type on the same line
1033 let ty_str = try_opt!(ty.rewrite(context, budget, type_indent)
1035 // The line was too short, try to put the type on the next line
1037 // Remove the space after '='
1039 let type_indent = indent.block_indent(context.config);
1041 result.push_str(&type_indent.to_string(context.config));
1042 let budget = try_opt!(context.config
1044 .checked_sub(type_indent.width() + ";".len()));
1045 ty.rewrite(context, budget, type_indent)
1047 result.push_str(&ty_str);
1048 result.push_str(";");
1052 fn type_annotation_spacing(config: &Config) -> (&str, &str) {
1053 (if config.space_before_type_annotation {
1058 if config.space_after_type_annotation_colon {
1065 impl Rewrite for ast::StructField {
1066 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
1067 if contains_skip(&self.attrs) {
1068 let span = context.snippet(mk_sp(self.attrs[0].span.lo, self.span.hi));
1069 return wrap_str(span, context.config.max_width, width, offset);
1072 let name = self.ident;
1073 let vis = format_visibility(&self.vis);
1074 let mut attr_str = try_opt!(self.attrs
1075 .rewrite(context, context.config.max_width - offset.width(), offset));
1076 if !attr_str.is_empty() {
1077 attr_str.push('\n');
1078 attr_str.push_str(&offset.to_string(context.config));
1081 let type_annotation_spacing = type_annotation_spacing(context.config);
1082 let result = match name {
1084 format!("{}{}{}{}:{}",
1088 type_annotation_spacing.0,
1089 type_annotation_spacing.1)
1091 None => format!("{}{}", attr_str, vis),
1094 let last_line_width = last_line_width(&result);
1095 let budget = try_opt!(width.checked_sub(last_line_width));
1096 let rewrite = try_opt!(self.ty.rewrite(context, budget, offset + last_line_width));
1097 Some(result + &rewrite)
1101 pub fn rewrite_static(prefix: &str,
1102 vis: &ast::Visibility,
1105 mutability: ast::Mutability,
1106 expr_opt: Option<&ptr::P<ast::Expr>>,
1107 context: &RewriteContext)
1109 let type_annotation_spacing = type_annotation_spacing(context.config);
1110 let prefix = format!("{}{} {}{}{}:{}",
1111 format_visibility(vis),
1113 format_mutability(mutability),
1115 type_annotation_spacing.0,
1116 type_annotation_spacing.1);
1118 let ty_str = try_opt!(ty.rewrite(context,
1119 context.config.max_width - context.block_indent.width() -
1121 context.block_indent));
1123 if let Some(expr) = expr_opt {
1124 let lhs = format!("{}{} =", prefix, ty_str);
1126 let remaining_width = context.config.max_width - context.block_indent.width() - 1;
1127 rewrite_assign_rhs(context, lhs, expr, remaining_width, context.block_indent)
1130 let lhs = format!("{}{};", prefix, ty_str);
1135 pub fn rewrite_associated_type(ident: ast::Ident,
1136 ty_opt: Option<&ptr::P<ast::Ty>>,
1137 ty_param_bounds_opt: Option<&ast::TyParamBounds>,
1138 context: &RewriteContext,
1141 let prefix = format!("type {}", ident);
1143 let type_bounds_str = if let Some(ty_param_bounds) = ty_param_bounds_opt {
1144 let bounds: &[_] = ty_param_bounds;
1145 let bound_str = try_opt!(bounds.iter()
1146 .map(|ty_bound| ty_bound.rewrite(context, context.config.max_width, indent))
1147 .intersperse(Some(" + ".to_string()))
1148 .collect::<Option<String>>());
1149 if bounds.len() > 0 {
1150 format!(": {}", bound_str)
1158 if let Some(ty) = ty_opt {
1159 let ty_str = try_opt!(ty.rewrite(context,
1160 context.config.max_width - context.block_indent.width() -
1163 context.block_indent));
1164 Some(format!("{} = {};", prefix, ty_str))
1166 Some(format!("{}{};", prefix, type_bounds_str))
1170 impl Rewrite for ast::FunctionRetTy {
1171 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
1173 ast::FunctionRetTy::Default(_) => Some(String::new()),
1174 ast::FunctionRetTy::Ty(ref ty) => {
1175 let inner_width = try_opt!(width.checked_sub(3));
1176 ty.rewrite(context, inner_width, offset + 3).map(|r| format!("-> {}", r))
1182 impl Rewrite for ast::Arg {
1183 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
1184 if is_named_arg(self) {
1185 let mut result = try_opt!(self.pat.rewrite(context, width, offset));
1187 if self.ty.node != ast::TyKind::Infer {
1188 if context.config.space_before_type_annotation {
1189 result.push_str(" ");
1191 result.push_str(":");
1192 if context.config.space_after_type_annotation_colon {
1193 result.push_str(" ");
1195 let max_width = try_opt!(width.checked_sub(result.len()));
1196 let ty_str = try_opt!(self.ty.rewrite(context, max_width, offset + result.len()));
1197 result.push_str(&ty_str);
1202 self.ty.rewrite(context, width, offset)
1207 fn rewrite_explicit_self(explicit_self: &ast::ExplicitSelf,
1209 context: &RewriteContext)
1211 match explicit_self.node {
1212 ast::SelfKind::Region(lt, m) => {
1213 let mut_str = format_mutability(m);
1217 try_opt!(l.rewrite(context, usize::max_value(), Indent::empty()));
1218 Some(format!("&{} {}self", lifetime_str, mut_str))
1220 None => Some(format!("&{}self", mut_str)),
1223 ast::SelfKind::Explicit(ref ty, _) => {
1224 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1226 let mutability = explicit_self_mutability(&args[0]);
1227 let type_str = try_opt!(ty.rewrite(context, usize::max_value(), Indent::empty()));
1229 Some(format!("{}self: {}", format_mutability(mutability), type_str))
1231 ast::SelfKind::Value(_) => {
1232 assert!(!args.is_empty(), "&[ast::Arg] shouldn't be empty.");
1234 let mutability = explicit_self_mutability(&args[0]);
1236 Some(format!("{}self", format_mutability(mutability)))
1241 // Hacky solution caused by absence of `Mutability` in `SelfValue` and
1242 // `SelfExplicit` variants of `ast::ExplicitSelf_`.
1243 fn explicit_self_mutability(arg: &ast::Arg) -> ast::Mutability {
1244 if let ast::PatKind::Ident(ast::BindingMode::ByValue(mutability), _, _) = arg.pat.node {
1251 pub fn span_lo_for_arg(arg: &ast::Arg) -> BytePos {
1252 if is_named_arg(arg) {
1259 pub fn span_hi_for_arg(arg: &ast::Arg) -> BytePos {
1261 ast::TyKind::Infer if is_named_arg(arg) => arg.pat.span.hi,
1262 _ => arg.ty.span.hi,
1266 pub fn is_named_arg(arg: &ast::Arg) -> bool {
1267 if let ast::PatKind::Ident(_, ident, _) = arg.pat.node {
1268 ident.node != token::keywords::Invalid.ident()
1274 fn span_for_return(ret: &ast::FunctionRetTy) -> Span {
1276 ast::FunctionRetTy::Default(ref span) => span.clone(),
1277 ast::FunctionRetTy::Ty(ref ty) => ty.span,
1281 fn span_for_ty_param(ty: &ast::TyParam) -> Span {
1282 // Note that ty.span is the span for ty.ident, not the whole item.
1283 let lo = ty.span.lo;
1284 if let Some(ref def) = ty.default {
1285 return mk_sp(lo, def.span.hi);
1287 if ty.bounds.is_empty() {
1290 let hi = match ty.bounds[ty.bounds.len() - 1] {
1291 ast::TyParamBound::TraitTyParamBound(ref ptr, _) => ptr.span.hi,
1292 ast::TyParamBound::RegionTyParamBound(ref l) => l.span.hi,
1297 fn span_for_where_pred(pred: &ast::WherePredicate) -> Span {
1299 ast::WherePredicate::BoundPredicate(ref p) => p.span,
1300 ast::WherePredicate::RegionPredicate(ref p) => p.span,
1301 ast::WherePredicate::EqPredicate(ref p) => p.span,
1305 // Return type is (result, force_new_line_for_brace)
1306 fn rewrite_fn_base(context: &RewriteContext,
1310 generics: &ast::Generics,
1311 unsafety: ast::Unsafety,
1312 constness: ast::Constness,
1313 defaultness: ast::Defaultness,
1315 vis: &ast::Visibility,
1317 newline_brace: bool,
1319 -> Option<(String, bool)> {
1320 let mut force_new_line_for_brace = false;
1321 // FIXME we'll lose any comments in between parts of the function decl, but
1322 // anyone who comments there probably deserves what they get.
1324 let where_clause = &generics.where_clause;
1326 let mut result = String::with_capacity(1024);
1327 // Vis unsafety abi.
1328 result.push_str(&*format_visibility(vis));
1330 if let ast::Defaultness::Default = defaultness {
1331 result.push_str("default ");
1334 if let ast::Constness::Const = constness {
1335 result.push_str("const ");
1338 result.push_str(::utils::format_unsafety(unsafety));
1340 if abi != abi::Abi::Rust {
1341 result.push_str(&::utils::format_abi(abi, context.config.force_explicit_abi));
1345 result.push_str("fn ");
1346 result.push_str(&ident.to_string());
1349 let generics_indent = indent + result.len();
1350 let generics_span = mk_sp(span.lo, span_for_return(&fd.output).lo);
1351 let generics_str = try_opt!(rewrite_generics(context,
1354 context.config.max_width,
1357 result.push_str(&generics_str);
1359 // Note that if the width and indent really matter, we'll re-layout the
1360 // return type later anyway.
1361 let ret_str = try_opt!(fd.output
1362 .rewrite(&context, context.config.max_width - indent.width(), indent));
1364 let multi_line_ret_str = ret_str.contains('\n');
1365 let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() };
1368 let (mut one_line_budget, mut multi_line_budget, mut arg_indent) =
1369 try_opt!(compute_budgets_for_args(context, &result, indent, ret_str_len, newline_brace));
1371 if context.config.fn_args_layout == FnArgLayoutStyle::Block ||
1372 context.config.fn_args_layout == FnArgLayoutStyle::BlockAlways {
1373 arg_indent = indent.block_indent(context.config);
1374 multi_line_budget = context.config.max_width - arg_indent.width();
1377 debug!("rewrite_fn: one_line_budget: {}, multi_line_budget: {}, arg_indent: {:?}",
1382 // Check if vertical layout was forced by compute_budget_for_args.
1383 if one_line_budget == 0 {
1384 if context.config.fn_args_paren_newline {
1386 result.push_str(&arg_indent.to_string(context.config));
1387 arg_indent = arg_indent + 1; // extra space for `(`
1390 result.push_str("(\n");
1391 result.push_str(&arg_indent.to_string(context.config));
1397 if multi_line_ret_str {
1398 one_line_budget = 0;
1401 // A conservative estimation, to goal is to be over all parens in generics
1402 let args_start = generics.ty_params
1404 .map_or(span.lo, |tp| end_typaram(tp));
1405 let args_span = mk_sp(context.codemap.span_after(mk_sp(args_start, span.hi), "("),
1406 span_for_return(&fd.output).lo);
1407 let arg_str = try_opt!(rewrite_args(context,
1409 fd.get_self().as_ref(),
1417 let multi_line_arg_str = arg_str.contains('\n');
1419 let put_args_in_block = match context.config.fn_args_layout {
1420 FnArgLayoutStyle::Block => multi_line_arg_str,
1421 FnArgLayoutStyle::BlockAlways => true,
1423 } && !fd.inputs.is_empty();
1425 if put_args_in_block {
1426 arg_indent = indent.block_indent(context.config);
1428 result.push_str(&arg_indent.to_string(context.config));
1429 result.push_str(&arg_str);
1431 result.push_str(&indent.to_string(context.config));
1434 result.push_str(&arg_str);
1439 if !ret_str.is_empty() {
1440 let ret_should_indent = match context.config.fn_args_layout {
1441 // If our args are block layout then we surely must have space.
1442 FnArgLayoutStyle::Block if put_args_in_block => false,
1443 FnArgLayoutStyle::BlockAlways => false,
1445 // If we've already gone multi-line, or the return type would push over the max
1446 // width, then put the return type on a new line. With the +1 for the signature
1447 // length an additional space between the closing parenthesis of the argument and
1448 // the arrow '->' is considered.
1449 let mut sig_length = result.len() + indent.width() + ret_str_len + 1;
1451 // If there is no where clause, take into account the space after the return type
1453 if where_clause.predicates.is_empty() {
1457 let overlong_sig = sig_length > context.config.max_width;
1459 result.contains('\n') || multi_line_ret_str || overlong_sig
1462 let ret_indent = if ret_should_indent {
1463 let indent = match context.config.fn_return_indent {
1464 ReturnIndent::WithWhereClause => indent + 4,
1465 // Aligning with non-existent args looks silly.
1466 _ if arg_str.is_empty() => {
1467 force_new_line_for_brace = true;
1470 // FIXME: we might want to check that using the arg indent
1471 // doesn't blow our budget, and if it does, then fallback to
1472 // the where clause indent.
1477 result.push_str(&indent.to_string(context.config));
1481 Indent::new(indent.width(), result.len())
1484 if multi_line_ret_str {
1485 // Now that we know the proper indent and width, we need to
1486 // re-layout the return type.
1487 let budget = try_opt!(context.config.max_width.checked_sub(ret_indent.width()));
1488 let ret_str = try_opt!(fd.output.rewrite(context, budget, ret_indent));
1489 result.push_str(&ret_str);
1491 result.push_str(&ret_str);
1494 // Comment between return type and the end of the decl.
1495 let snippet_lo = fd.output.span().hi;
1496 if where_clause.predicates.is_empty() {
1497 let snippet_hi = span.hi;
1498 let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi));
1499 let snippet = snippet.trim();
1500 if !snippet.is_empty() {
1502 result.push_str(snippet);
1505 // FIXME it would be nice to catch comments between the return type
1506 // and the where clause, but we don't have a span for the where
1511 let should_compress_where = match context.config.where_density {
1512 Density::Compressed => !result.contains('\n') || put_args_in_block,
1513 Density::CompressedIfEmpty => !has_body && !result.contains('\n'),
1515 } || (put_args_in_block && ret_str.is_empty());
1517 let where_density = if should_compress_where {
1524 let where_budget = try_opt!(context.config.max_width.checked_sub(last_line_width(&result)));
1525 let where_clause_str = try_opt!(rewrite_where_clause(context,
1528 context.config.fn_brace_style,
1536 if last_line_width(&result) + where_clause_str.len() > context.config.max_width &&
1537 !where_clause_str.contains('\n') {
1541 result.push_str(&where_clause_str);
1543 Some((result, force_new_line_for_brace))
1546 fn rewrite_args(context: &RewriteContext,
1548 explicit_self: Option<&ast::ExplicitSelf>,
1549 one_line_budget: usize,
1550 multi_line_budget: usize,
1556 let mut arg_item_strs = try_opt!(args.iter()
1557 .map(|arg| arg.rewrite(&context, multi_line_budget, arg_indent))
1558 .collect::<Option<Vec<_>>>());
1560 // Account for sugary self.
1561 // FIXME: the comment for the self argument is dropped. This is blocked
1562 // on rust issue #27522.
1564 explicit_self.and_then(|explicit_self| rewrite_explicit_self(explicit_self, args, context))
1565 .map_or(1, |self_str| {
1566 arg_item_strs[0] = self_str;
1570 // Comments between args.
1571 let mut arg_items = Vec::new();
1573 arg_items.push(ListItem::from_str(""));
1576 // FIXME(#21): if there are no args, there might still be a comment, but
1577 // without spans for the comment or parens, there is no chance of
1578 // getting it right. You also don't get to put a comment on self, unless
1580 if args.len() >= min_args || variadic {
1581 let comment_span_start = if min_args == 2 {
1582 let second_arg_start = if arg_has_pattern(&args[1]) {
1587 let reduced_span = mk_sp(span.lo, second_arg_start);
1589 context.codemap.span_after_last(reduced_span, ",")
1594 enum ArgumentKind<'a> {
1595 Regular(&'a ast::Arg),
1599 let variadic_arg = if variadic {
1600 let variadic_span = mk_sp(args.last().unwrap().ty.span.hi, span.hi);
1601 let variadic_start = context.codemap.span_after(variadic_span, "...") - BytePos(3);
1602 Some(ArgumentKind::Variadic(variadic_start))
1607 let more_items = itemize_list(context.codemap,
1608 args[min_args - 1..]
1610 .map(ArgumentKind::Regular)
1611 .chain(variadic_arg),
1615 ArgumentKind::Regular(arg) => span_lo_for_arg(arg),
1616 ArgumentKind::Variadic(start) => start,
1621 ArgumentKind::Regular(arg) => arg.ty.span.hi,
1622 ArgumentKind::Variadic(start) => start + BytePos(3),
1627 ArgumentKind::Regular(..) => None,
1628 ArgumentKind::Variadic(..) => Some("...".to_owned()),
1634 arg_items.extend(more_items);
1637 for (item, arg) in arg_items.iter_mut().zip(arg_item_strs) {
1638 item.item = Some(arg);
1641 let indent = match context.config.fn_arg_indent {
1642 BlockIndentStyle::Inherit => indent,
1643 BlockIndentStyle::Tabbed => indent.block_indent(context.config),
1644 BlockIndentStyle::Visual => arg_indent,
1647 let tactic = definitive_tactic(&arg_items,
1648 context.config.fn_args_density.to_list_tactic(),
1650 let budget = match tactic {
1651 DefinitiveListTactic::Horizontal => one_line_budget,
1652 _ => multi_line_budget,
1655 debug!("rewrite_args: budget: {}, tactic: {:?}", budget, tactic);
1657 let end_with_newline = match context.config.fn_args_layout {
1658 FnArgLayoutStyle::Block |
1659 FnArgLayoutStyle::BlockAlways => true,
1663 let fmt = ListFormatting {
1666 trailing_separator: SeparatorTactic::Never,
1669 ends_with_newline: end_with_newline,
1670 config: context.config,
1673 write_list(&arg_items, &fmt)
1676 fn arg_has_pattern(arg: &ast::Arg) -> bool {
1677 if let ast::PatKind::Ident(_,
1679 node: ast::Ident { name: ast::Name(0u32), .. },
1689 fn compute_budgets_for_args(context: &RewriteContext,
1693 newline_brace: bool)
1694 -> Option<((usize, usize, Indent))> {
1695 // Try keeping everything on the same line.
1696 if !result.contains('\n') {
1697 // 3 = `() `, space is before ret_string.
1698 let mut used_space = indent.width() + result.len() + ret_str_len + 3;
1702 let one_line_budget = context.config.max_width.checked_sub(used_space).unwrap_or(0);
1704 if one_line_budget > 0 {
1706 let multi_line_budget =
1707 try_opt!(context.config.max_width.checked_sub(indent.width() + result.len() + 4));
1709 return Some((one_line_budget, multi_line_budget, indent + result.len() + 1));
1713 // Didn't work. we must force vertical layout and put args on a newline.
1714 let new_indent = indent.block_indent(context.config);
1715 let used_space = new_indent.width() + 4; // Account for `(` and `)` and possibly ` {`.
1716 let max_space = context.config.max_width;
1717 if used_space <= max_space {
1718 Some((0, max_space - used_space, new_indent))
1720 // Whoops! bankrupt.
1725 fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> bool {
1726 match config.fn_brace_style {
1727 BraceStyle::AlwaysNextLine => true,
1728 BraceStyle::SameLineWhere if !where_clause.predicates.is_empty() => true,
1733 fn rewrite_generics(context: &RewriteContext,
1734 generics: &ast::Generics,
1737 generics_offset: Indent,
1740 // FIXME: convert bounds to where clauses where they get too big or if
1741 // there is a where clause at all.
1742 let lifetimes: &[_] = &generics.lifetimes;
1743 let tys: &[_] = &generics.ty_params;
1744 if lifetimes.is_empty() && tys.is_empty() {
1745 return Some(String::new());
1748 let offset = match context.config.generics_indent {
1749 BlockIndentStyle::Inherit => offset,
1750 BlockIndentStyle::Tabbed => offset.block_indent(context.config),
1752 BlockIndentStyle::Visual => generics_offset + 1,
1755 let h_budget = try_opt!(width.checked_sub(generics_offset.width() + 2));
1756 // FIXME: might need to insert a newline if the generics are really long.
1758 // Strings for the generics.
1759 let lt_strs = lifetimes.iter().map(|lt| lt.rewrite(context, h_budget, offset));
1760 let ty_strs = tys.iter().map(|ty_param| ty_param.rewrite(context, h_budget, offset));
1762 // Extract comments between generics.
1763 let lt_spans = lifetimes.iter().map(|l| {
1764 let hi = if l.bounds.is_empty() {
1767 l.bounds[l.bounds.len() - 1].span.hi
1769 mk_sp(l.lifetime.span.lo, hi)
1771 let ty_spans = tys.iter().map(span_for_ty_param);
1773 let items = itemize_list(context.codemap,
1774 lt_spans.chain(ty_spans).zip(lt_strs.chain(ty_strs)),
1778 // FIXME: don't clone
1779 |&(_, ref str)| str.clone(),
1780 context.codemap.span_after(span, "<"),
1782 let list_str = try_opt!(format_item_list(items, h_budget, offset, context.config));
1784 Some(format!("<{}>", list_str))
1787 fn rewrite_trait_bounds(context: &RewriteContext,
1788 type_param_bounds: &ast::TyParamBounds,
1792 let bounds: &[_] = type_param_bounds;
1794 if bounds.is_empty() {
1795 return Some(String::new());
1798 let bound_str = try_opt!(bounds.iter()
1799 .map(|ty_bound| ty_bound.rewrite(&context, width, indent))
1800 .intersperse(Some(" + ".to_string()))
1801 .collect::<Option<String>>());
1803 let mut result = String::new();
1804 result.push_str(": ");
1805 result.push_str(&bound_str);
1809 fn rewrite_where_clause(context: &RewriteContext,
1810 where_clause: &ast::WhereClause,
1812 brace_style: BraceStyle,
1817 allow_trailing_comma: bool,
1818 span_end: Option<BytePos>)
1820 if where_clause.predicates.is_empty() {
1821 return Some(String::new());
1824 let extra_indent = match context.config.where_indent {
1825 BlockIndentStyle::Inherit => Indent::empty(),
1826 BlockIndentStyle::Tabbed | BlockIndentStyle::Visual => Indent::new(config.tab_spaces, 0),
1829 let offset = match context.config.where_pred_indent {
1830 BlockIndentStyle::Inherit => indent + extra_indent,
1831 BlockIndentStyle::Tabbed => indent + extra_indent.block_indent(config),
1832 // 6 = "where ".len()
1833 BlockIndentStyle::Visual => indent + extra_indent + 6,
1835 // FIXME: if where_pred_indent != Visual, then the budgets below might
1836 // be out by a char or two.
1838 let budget = context.config.max_width - offset.width();
1839 let span_start = span_for_where_pred(&where_clause.predicates[0]).lo;
1840 // If we don't have the start of the next span, then use the end of the
1841 // predicates, but that means we miss comments.
1842 let len = where_clause.predicates.len();
1843 let end_of_preds = span_for_where_pred(&where_clause.predicates[len - 1]).hi;
1844 let span_end = span_end.unwrap_or(end_of_preds);
1845 let items = itemize_list(context.codemap,
1846 where_clause.predicates.iter(),
1848 |pred| span_for_where_pred(pred).lo,
1849 |pred| span_for_where_pred(pred).hi,
1850 |pred| pred.rewrite(context, budget, offset),
1853 let item_vec = items.collect::<Vec<_>>();
1854 // FIXME: we don't need to collect here if the where_layout isn't
1855 // HorizontalVertical.
1856 let tactic = definitive_tactic(&item_vec, context.config.where_layout, budget);
1857 let use_trailing_comma = allow_trailing_comma && context.config.where_trailing_comma;
1859 let fmt = ListFormatting {
1862 trailing_separator: SeparatorTactic::from_bool(use_trailing_comma),
1865 ends_with_newline: true,
1866 config: context.config,
1868 let preds_str = try_opt!(write_list(&item_vec, &fmt));
1870 let end_length = if terminator == "{" {
1871 // If the brace is on the next line we don't need to count it otherwise it needs two
1874 BraceStyle::AlwaysNextLine |
1875 BraceStyle::SameLineWhere => 0,
1876 BraceStyle::PreferSameLine => 2,
1878 } else if terminator == "=" {
1883 if density == Density::Tall || preds_str.contains('\n') ||
1884 indent.width() + " where ".len() + preds_str.len() + end_length > width {
1885 Some(format!("\n{}where {}",
1886 (indent + extra_indent).to_string(context.config),
1889 Some(format!(" where {}", preds_str))
1893 fn format_header(item_name: &str, ident: ast::Ident, vis: &ast::Visibility) -> String {
1894 format!("{}{}{}", format_visibility(vis), item_name, ident)
1897 fn format_generics(context: &RewriteContext,
1898 generics: &ast::Generics,
1901 brace_style: BraceStyle,
1902 force_same_line_brace: bool,
1904 generics_offset: Indent,
1907 let mut result = try_opt!(rewrite_generics(context,
1910 context.config.max_width,
1914 if !generics.where_clause.predicates.is_empty() || result.contains('\n') {
1915 let budget = try_opt!(context.config.max_width.checked_sub(last_line_width(&result)));
1916 let where_clause_str = try_opt!(rewrite_where_clause(context,
1917 &generics.where_clause,
1920 context.block_indent,
1926 result.push_str(&where_clause_str);
1927 if !force_same_line_brace &&
1928 (brace_style == BraceStyle::SameLineWhere || brace_style == BraceStyle::AlwaysNextLine) {
1930 result.push_str(&context.block_indent.to_string(context.config));
1934 result.push_str(opener);
1936 if !force_same_line_brace && brace_style == BraceStyle::AlwaysNextLine {
1938 result.push_str(&context.block_indent.to_string(context.config));
1942 result.push_str(opener);