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.
15 use syntax::{ast, ptr};
16 use syntax::codemap::{BytePos, CodeMap, Span};
18 use chains::rewrite_chain;
20 use codemap::{LineRangeUtils, SpanUtils};
21 use comment::{combine_strs_with_missing_comments, contains_comment, recover_comment_removed,
22 rewrite_comment, rewrite_missing_comment, CharClasses, FindUncommented};
23 use config::{Config, ControlBraceStyle, IndentStyle};
24 use lists::{definitive_tactic, itemize_list, shape_for_tactic, struct_lit_formatting,
25 struct_lit_shape, struct_lit_tactic, write_list, ListFormatting, ListItem, Separator};
26 use macros::{rewrite_macro, MacroArg, MacroPosition};
27 use matches::rewrite_match;
29 use patterns::{can_be_overflowed_pat, is_short_pattern, TuplePatField};
30 use rewrite::{Rewrite, RewriteContext};
31 use shape::{Indent, Shape};
33 use string::{rewrite_string, StringFormat};
34 use types::{can_be_overflowed_type, rewrite_path, PathContext};
35 use utils::{colon_spaces, contains_skip, count_newlines, first_line_width, inner_attributes,
36 last_line_extendable, last_line_width, mk_sp, outer_attributes, paren_overhead,
37 ptr_vec_to_ref_vec, semicolon_for_stmt, wrap_str};
38 use vertical::rewrite_with_alignment;
39 use visitor::FmtVisitor;
41 impl Rewrite for ast::Expr {
42 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
43 format_expr(self, ExprType::SubExpression, context, shape)
47 #[derive(Copy, Clone, PartialEq)]
56 context: &RewriteContext,
59 skip_out_of_file_lines_range!(context, expr.span);
61 if contains_skip(&*expr.attrs) {
62 return Some(context.snippet(expr.span()).to_owned());
65 let expr_rw = match expr.node {
66 ast::ExprKind::Array(ref expr_vec) => rewrite_array(
67 &ptr_vec_to_ref_vec(expr_vec),
69 context.snippet_provider.span_after(expr.span, "["),
76 ast::ExprKind::Lit(ref l) => rewrite_literal(context, l, shape),
77 ast::ExprKind::Call(ref callee, ref args) => {
78 let inner_span = mk_sp(callee.span.hi(), expr.span.hi());
79 let callee_str = callee.rewrite(context, shape)?;
80 rewrite_call(context, &callee_str, args, inner_span, shape)
82 ast::ExprKind::Paren(ref subexpr) => rewrite_paren(context, subexpr, shape, expr.span),
83 ast::ExprKind::Binary(ref op, ref lhs, ref rhs) => {
84 // FIXME: format comments between operands and operator
88 PairParts::new("", &format!(" {} ", context.snippet(op.span)), ""),
91 context.config.binop_separator(),
94 ast::ExprKind::Unary(ref op, ref subexpr) => rewrite_unary_op(context, op, subexpr, shape),
95 ast::ExprKind::Struct(ref path, ref fields, ref base) => rewrite_struct_lit(
99 base.as_ref().map(|e| &**e),
103 ast::ExprKind::Tup(ref items) => {
104 rewrite_tuple(context, &ptr_vec_to_ref_vec(items), expr.span, shape)
106 ast::ExprKind::If(..)
107 | ast::ExprKind::IfLet(..)
108 | ast::ExprKind::ForLoop(..)
109 | ast::ExprKind::Loop(..)
110 | ast::ExprKind::While(..)
111 | ast::ExprKind::WhileLet(..) => to_control_flow(expr, expr_type)
112 .and_then(|control_flow| control_flow.rewrite(context, shape)),
113 ast::ExprKind::Block(ref block) => {
115 ExprType::Statement => {
116 if is_unsafe_block(block) {
117 rewrite_block(block, Some(&expr.attrs), context, shape)
118 } else if let rw @ Some(_) =
119 rewrite_empty_block(context, block, Some(&expr.attrs), "", shape)
121 // Rewrite block without trying to put it in a single line.
124 let prefix = block_prefix(context, block, shape)?;
125 rewrite_block_with_visitor(
135 ExprType::SubExpression => rewrite_block(block, Some(&expr.attrs), context, shape),
138 ast::ExprKind::Match(ref cond, ref arms) => {
139 rewrite_match(context, cond, arms, shape, expr.span, &expr.attrs)
141 ast::ExprKind::Path(ref qself, ref path) => {
142 rewrite_path(context, PathContext::Expr, qself.as_ref(), path, shape)
144 ast::ExprKind::Assign(ref lhs, ref rhs) => {
145 rewrite_assignment(context, lhs, rhs, None, shape)
147 ast::ExprKind::AssignOp(ref op, ref lhs, ref rhs) => {
148 rewrite_assignment(context, lhs, rhs, Some(op), shape)
150 ast::ExprKind::Continue(ref opt_label) => {
151 let id_str = match *opt_label {
152 Some(label) => format!(" {}", label.ident),
153 None => String::new(),
155 Some(format!("continue{}", id_str))
157 ast::ExprKind::Break(ref opt_label, ref opt_expr) => {
158 let id_str = match *opt_label {
159 Some(label) => format!(" {}", label.ident),
160 None => String::new(),
163 if let Some(ref expr) = *opt_expr {
164 rewrite_unary_prefix(context, &format!("break{} ", id_str), &**expr, shape)
166 Some(format!("break{}", id_str))
169 ast::ExprKind::Yield(ref opt_expr) => if let Some(ref expr) = *opt_expr {
170 rewrite_unary_prefix(context, "yield ", &**expr, shape)
172 Some("yield".to_string())
174 ast::ExprKind::Closure(capture, movability, ref fn_decl, ref body, _) => {
175 closures::rewrite_closure(
185 ast::ExprKind::Try(..)
186 | ast::ExprKind::Field(..)
187 | ast::ExprKind::TupField(..)
188 | ast::ExprKind::MethodCall(..) => rewrite_chain(expr, context, shape),
189 ast::ExprKind::Mac(ref mac) => {
190 rewrite_macro(mac, None, context, shape, MacroPosition::Expression).or_else(|| {
192 context.snippet(expr.span).to_owned(),
193 context.config.max_width(),
198 ast::ExprKind::Ret(None) => Some("return".to_owned()),
199 ast::ExprKind::Ret(Some(ref expr)) => {
200 rewrite_unary_prefix(context, "return ", &**expr, shape)
202 ast::ExprKind::Box(ref expr) => rewrite_unary_prefix(context, "box ", &**expr, shape),
203 ast::ExprKind::AddrOf(mutability, ref expr) => {
204 rewrite_expr_addrof(context, mutability, expr, shape)
206 ast::ExprKind::Cast(ref expr, ref ty) => rewrite_pair(
209 PairParts::new("", " as ", ""),
212 SeparatorPlace::Front,
214 ast::ExprKind::Type(ref expr, ref ty) => rewrite_pair(
217 PairParts::new("", ": ", ""),
220 SeparatorPlace::Back,
222 ast::ExprKind::Index(ref expr, ref index) => {
223 rewrite_index(&**expr, &**index, context, shape)
225 ast::ExprKind::Repeat(ref expr, ref repeats) => {
226 let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() {
234 PairParts::new(lbr, "; ", rbr),
237 SeparatorPlace::Back,
240 ast::ExprKind::Range(ref lhs, ref rhs, limits) => {
241 let delim = match limits {
242 ast::RangeLimits::HalfOpen => "..",
243 ast::RangeLimits::Closed => "..=",
246 fn needs_space_before_range(context: &RewriteContext, lhs: &ast::Expr) -> bool {
248 ast::ExprKind::Lit(ref lit) => match lit.node {
249 ast::LitKind::FloatUnsuffixed(..) => {
250 context.snippet(lit.span).ends_with('.')
258 match (lhs.as_ref().map(|x| &**x), rhs.as_ref().map(|x| &**x)) {
259 (Some(lhs), Some(rhs)) => {
260 let sp_delim = if context.config.spaces_around_ranges() {
261 format!(" {} ", delim)
262 } else if needs_space_before_range(context, lhs) {
263 format!(" {}", delim)
270 PairParts::new("", &sp_delim, ""),
273 context.config.binop_separator(),
276 (None, Some(rhs)) => {
277 let sp_delim = if context.config.spaces_around_ranges() {
278 format!("{} ", delim)
282 rewrite_unary_prefix(context, &sp_delim, &*rhs, shape)
284 (Some(lhs), None) => {
285 let sp_delim = if context.config.spaces_around_ranges() {
286 format!(" {}", delim)
290 rewrite_unary_suffix(context, &sp_delim, &*lhs, shape)
292 (None, None) => Some(delim.to_owned()),
295 // We do not format these expressions yet, but they should still
296 // satisfy our width restrictions.
297 ast::ExprKind::InPlace(..) | ast::ExprKind::InlineAsm(..) => {
298 Some(context.snippet(expr.span).to_owned())
300 ast::ExprKind::Catch(ref block) => {
301 if let rw @ Some(_) =
302 rewrite_single_line_block(context, "do catch ", block, Some(&expr.attrs), shape)
307 let budget = shape.width.checked_sub(9).unwrap_or(0);
315 Shape::legacy(budget, shape.indent)
323 .and_then(|expr_str| recover_comment_removed(expr_str, expr.span, context))
324 .and_then(|expr_str| {
325 let attrs = outer_attributes(&expr.attrs);
326 let attrs_str = attrs.rewrite(context, shape)?;
328 attrs.last().map_or(expr.span.lo(), |attr| attr.span.hi()),
331 combine_strs_with_missing_comments(context, &attrs_str, &expr_str, span, shape, false)
335 #[derive(new, Clone, Copy)]
336 pub struct PairParts<'a> {
342 pub fn rewrite_pair<LHS, RHS>(
346 context: &RewriteContext,
348 separator_place: SeparatorPlace,
354 let lhs_overhead = match separator_place {
355 SeparatorPlace::Back => shape.used_width() + pp.prefix.len() + pp.infix.trim_right().len(),
356 SeparatorPlace::Front => shape.used_width(),
358 let lhs_shape = Shape {
359 width: context.budget(lhs_overhead),
362 let lhs_result = lhs.rewrite(context, lhs_shape)
363 .map(|lhs_str| format!("{}{}", pp.prefix, lhs_str))?;
365 // Try to put both lhs and rhs on the same line.
366 let rhs_orig_result = shape
367 .offset_left(last_line_width(&lhs_result) + pp.infix.len())
368 .and_then(|s| s.sub_width(pp.suffix.len()))
369 .and_then(|rhs_shape| rhs.rewrite(context, rhs_shape));
370 if let Some(ref rhs_result) = rhs_orig_result {
371 // If the length of the lhs is equal to or shorter than the tab width or
372 // the rhs looks like block expression, we put the rhs on the same
373 // line with the lhs even if the rhs is multi-lined.
374 let allow_same_line = lhs_result.len() <= context.config.tab_spaces()
378 .map(|first_line| first_line.ends_with('{'))
380 if !rhs_result.contains('\n') || allow_same_line {
381 let one_line_width = last_line_width(&lhs_result) + pp.infix.len()
382 + first_line_width(rhs_result) + pp.suffix.len();
383 if one_line_width <= shape.width {
386 lhs_result, pp.infix, rhs_result, pp.suffix
392 // We have to use multiple lines.
393 // Re-evaluate the rhs because we have more space now:
394 let mut rhs_shape = match context.config.indent_style() {
395 IndentStyle::Visual => shape
396 .sub_width(pp.suffix.len() + pp.prefix.len())?
397 .visual_indent(pp.prefix.len()),
398 IndentStyle::Block => {
399 // Try to calculate the initial constraint on the right hand side.
400 let rhs_overhead = shape.rhs_overhead(context.config);
401 Shape::indented(shape.indent.block_indent(context.config), context.config)
402 .sub_width(rhs_overhead)?
405 let infix = match separator_place {
406 SeparatorPlace::Back => pp.infix.trim_right(),
407 SeparatorPlace::Front => pp.infix.trim_left(),
409 if separator_place == SeparatorPlace::Front {
410 rhs_shape = rhs_shape.offset_left(infix.len())?;
412 let rhs_result = rhs.rewrite(context, rhs_shape)?;
413 let indent_str = rhs_shape.indent.to_string_with_newline(context.config);
414 let infix_with_sep = match separator_place {
415 SeparatorPlace::Back => format!("{}{}", infix, indent_str),
416 SeparatorPlace::Front => format!("{}{}", indent_str, infix),
420 lhs_result, infix_with_sep, rhs_result, pp.suffix
424 pub fn rewrite_array<T: Rewrite + Spanned + ToExpr>(
427 context: &RewriteContext,
429 trailing_comma: bool,
430 ) -> Option<String> {
431 let bracket_size = if context.config.spaces_within_parens_and_brackets() {
437 let nested_shape = match context.config.indent_style() {
438 IndentStyle::Block => shape
440 .block_indent(context.config.tab_spaces())
441 .with_max_width(context.config)
443 IndentStyle::Visual => shape
444 .visual_indent(bracket_size)
445 .sub_width(bracket_size * 2)?,
448 let items = itemize_list(
449 context.snippet_provider,
453 |item| item.span().lo(),
454 |item| item.span().hi(),
455 |item| item.rewrite(context, nested_shape),
459 ).collect::<Vec<_>>();
461 if items.is_empty() {
462 if context.config.spaces_within_parens_and_brackets() {
463 return Some("[ ]".to_string());
465 return Some("[]".to_string());
469 let tactic = array_tactic(context, shape, nested_shape, exprs, &items, bracket_size);
470 let ends_with_newline = tactic.ends_with_newline(context.config.indent_style());
472 let fmt = ListFormatting {
475 trailing_separator: if trailing_comma {
476 SeparatorTactic::Always
477 } else if context.inside_macro && !exprs.is_empty() {
478 let ends_with_bracket = context.snippet(span).ends_with(']');
479 let bracket_offset = if ends_with_bracket { 1 } else { 0 };
480 let snippet = context.snippet(mk_sp(span.lo(), span.hi() - BytePos(bracket_offset)));
481 let last_char_index = snippet.rfind(|c: char| !c.is_whitespace())?;
482 if &snippet[last_char_index..last_char_index + 1] == "," {
483 SeparatorTactic::Always
485 SeparatorTactic::Never
487 } else if context.config.indent_style() == IndentStyle::Visual {
488 SeparatorTactic::Never
490 SeparatorTactic::Vertical
492 separator_place: SeparatorPlace::Back,
495 preserve_newline: false,
496 config: context.config,
498 let list_str = write_list(&items, &fmt)?;
500 let result = if context.config.indent_style() == IndentStyle::Visual
501 || tactic == DefinitiveListTactic::Horizontal
503 if context.config.spaces_within_parens_and_brackets() && !list_str.is_empty() {
504 format!("[ {} ]", list_str)
506 format!("[{}]", list_str)
511 nested_shape.indent.to_string_with_newline(context.config),
513 shape.block().indent.to_string_with_newline(context.config)
520 fn array_tactic<T: Rewrite + Spanned + ToExpr>(
521 context: &RewriteContext,
527 ) -> DefinitiveListTactic {
528 let has_long_item = items
530 .any(|li| li.item.as_ref().map(|s| s.len() > 10).unwrap_or(false));
532 match context.config.indent_style() {
533 IndentStyle::Block => {
534 let tactic = match shape.width.checked_sub(2 * bracket_size) {
536 let tactic = ListTactic::LimitedHorizontalVertical(
537 context.config.width_heuristics().array_width,
539 definitive_tactic(items, tactic, Separator::Comma, width)
541 None => DefinitiveListTactic::Vertical,
543 if tactic == DefinitiveListTactic::Vertical && !has_long_item
544 && is_every_expr_simple(exprs)
546 DefinitiveListTactic::Mixed
551 IndentStyle::Visual => {
552 if has_long_item || items.iter().any(ListItem::is_multiline) {
555 ListTactic::LimitedHorizontalVertical(
556 context.config.width_heuristics().array_width,
562 DefinitiveListTactic::Mixed
568 fn rewrite_empty_block(
569 context: &RewriteContext,
571 attrs: Option<&[ast::Attribute]>,
574 ) -> Option<String> {
575 if attrs.map_or(false, |a| !inner_attributes(a).is_empty()) {
579 if block.stmts.is_empty() && !block_contains_comment(block, context.codemap) && shape.width >= 2
581 return Some(format!("{}{{}}", prefix));
584 // If a block contains only a single-line comment, then leave it on one line.
585 let user_str = context.snippet(block.span);
586 let user_str = user_str.trim();
587 if user_str.starts_with('{') && user_str.ends_with('}') {
588 let comment_str = user_str[1..user_str.len() - 1].trim();
589 if block.stmts.is_empty() && !comment_str.contains('\n') && !comment_str.starts_with("//")
590 && comment_str.len() + 4 <= shape.width
592 return Some(format!("{}{{ {} }}", prefix, comment_str));
599 fn block_prefix(context: &RewriteContext, block: &ast::Block, shape: Shape) -> Option<String> {
600 Some(match block.rules {
601 ast::BlockCheckMode::Unsafe(..) => {
602 let snippet = context.snippet(block.span);
603 let open_pos = snippet.find_uncommented("{")?;
604 // Extract comment between unsafe and block start.
605 let trimmed = &snippet[6..open_pos].trim();
607 if !trimmed.is_empty() {
608 // 9 = "unsafe {".len(), 7 = "unsafe ".len()
609 let budget = shape.width.checked_sub(9)?;
615 Shape::legacy(budget, shape.indent + 7),
623 ast::BlockCheckMode::Default => String::new(),
627 fn rewrite_single_line_block(
628 context: &RewriteContext,
631 attrs: Option<&[ast::Attribute]>,
633 ) -> Option<String> {
634 if is_simple_block(block, attrs, context.codemap) {
635 let expr_shape = shape.offset_left(last_line_width(prefix))?;
636 let expr_str = block.stmts[0].rewrite(context, expr_shape)?;
637 let result = format!("{}{{ {} }}", prefix, expr_str);
638 if result.len() <= shape.width && !result.contains('\n') {
645 pub fn rewrite_block_with_visitor(
646 context: &RewriteContext,
649 attrs: Option<&[ast::Attribute]>,
652 ) -> Option<String> {
653 if let rw @ Some(_) = rewrite_empty_block(context, block, attrs, prefix, shape) {
657 let mut visitor = FmtVisitor::from_context(context);
658 visitor.block_indent = shape.indent;
659 visitor.is_if_else_block = context.is_if_else_block;
661 ast::BlockCheckMode::Unsafe(..) => {
662 let snippet = context.snippet(block.span);
663 let open_pos = snippet.find_uncommented("{")?;
664 visitor.last_pos = block.span.lo() + BytePos(open_pos as u32)
666 ast::BlockCheckMode::Default => visitor.last_pos = block.span.lo(),
669 let inner_attrs = attrs.map(inner_attributes);
670 visitor.visit_block(block, inner_attrs.as_ref().map(|a| &**a), has_braces);
671 Some(format!("{}{}", prefix, visitor.buffer))
674 impl Rewrite for ast::Block {
675 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
676 rewrite_block(self, None, context, shape)
682 attrs: Option<&[ast::Attribute]>,
683 context: &RewriteContext,
685 ) -> Option<String> {
686 let prefix = block_prefix(context, block, shape)?;
688 // shape.width is used only for the single line case: either the empty block `{}`,
689 // or an unsafe expression `unsafe { e }`.
690 if let rw @ Some(_) = rewrite_empty_block(context, block, attrs, &prefix, shape) {
694 let result = rewrite_block_with_visitor(context, &prefix, block, attrs, shape, true);
695 if let Some(ref result_str) = result {
696 if result_str.lines().count() <= 3 {
697 if let rw @ Some(_) = rewrite_single_line_block(context, &prefix, block, attrs, shape) {
706 impl Rewrite for ast::Stmt {
707 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
708 skip_out_of_file_lines_range!(context, self.span());
710 let result = match self.node {
711 ast::StmtKind::Local(ref local) => local.rewrite(context, shape),
712 ast::StmtKind::Expr(ref ex) | ast::StmtKind::Semi(ref ex) => {
713 let suffix = if semicolon_for_stmt(context, self) {
719 let shape = shape.sub_width(suffix.len())?;
720 format_expr(ex, ExprType::Statement, context, shape).map(|s| s + suffix)
722 ast::StmtKind::Mac(..) | ast::StmtKind::Item(..) => None,
724 result.and_then(|res| recover_comment_removed(res, self.span(), context))
728 // Rewrite condition if the given expression has one.
729 pub fn rewrite_cond(context: &RewriteContext, expr: &ast::Expr, shape: Shape) -> Option<String> {
731 ast::ExprKind::Match(ref cond, _) => {
733 let cond_shape = match context.config.indent_style() {
734 IndentStyle::Visual => shape.shrink_left(6).and_then(|s| s.sub_width(2))?,
735 IndentStyle::Block => shape.offset_left(8)?,
737 cond.rewrite(context, cond_shape)
739 _ => to_control_flow(expr, ExprType::SubExpression).and_then(|control_flow| {
741 String::from("\n") + &shape.indent.block_only().to_string(context.config);
743 .rewrite_cond(context, shape, &alt_block_sep)
744 .and_then(|rw| Some(rw.0))
749 // Abstraction over control flow expressions
751 struct ControlFlow<'a> {
752 cond: Option<&'a ast::Expr>,
753 block: &'a ast::Block,
754 else_block: Option<&'a ast::Expr>,
755 label: Option<ast::Label>,
756 pats: Vec<&'a ast::Pat>,
760 allow_single_line: bool,
761 // True if this is an `if` expression in an `else if` :-( hacky
766 fn to_control_flow(expr: &ast::Expr, expr_type: ExprType) -> Option<ControlFlow> {
768 ast::ExprKind::If(ref cond, ref if_block, ref else_block) => Some(ControlFlow::new_if(
772 else_block.as_ref().map(|e| &**e),
773 expr_type == ExprType::SubExpression,
777 ast::ExprKind::IfLet(ref pat, ref cond, ref if_block, ref else_block) => {
778 Some(ControlFlow::new_if(
780 ptr_vec_to_ref_vec(pat),
782 else_block.as_ref().map(|e| &**e),
783 expr_type == ExprType::SubExpression,
788 ast::ExprKind::ForLoop(ref pat, ref cond, ref block, label) => {
789 Some(ControlFlow::new_for(pat, cond, block, label, expr.span))
791 ast::ExprKind::Loop(ref block, label) => {
792 Some(ControlFlow::new_loop(block, label, expr.span))
794 ast::ExprKind::While(ref cond, ref block, label) => Some(ControlFlow::new_while(
801 ast::ExprKind::WhileLet(ref pat, ref cond, ref block, label) => Some(
802 ControlFlow::new_while(ptr_vec_to_ref_vec(pat), cond, block, label, expr.span),
808 fn choose_matcher(pats: &[&ast::Pat]) -> &'static str {
816 impl<'a> ControlFlow<'a> {
819 pats: Vec<&'a ast::Pat>,
820 block: &'a ast::Block,
821 else_block: Option<&'a ast::Expr>,
822 allow_single_line: bool,
825 ) -> ControlFlow<'a> {
826 let matcher = choose_matcher(&pats);
842 fn new_loop(block: &'a ast::Block, label: Option<ast::Label>, span: Span) -> ControlFlow<'a> {
852 allow_single_line: false,
859 pats: Vec<&'a ast::Pat>,
861 block: &'a ast::Block,
862 label: Option<ast::Label>,
864 ) -> ControlFlow<'a> {
865 let matcher = choose_matcher(&pats);
875 allow_single_line: false,
884 block: &'a ast::Block,
885 label: Option<ast::Label>,
887 ) -> ControlFlow<'a> {
897 allow_single_line: false,
903 fn rewrite_single_line(
906 context: &RewriteContext,
908 ) -> Option<String> {
909 assert!(self.allow_single_line);
910 let else_block = self.else_block?;
911 let fixed_cost = self.keyword.len() + " { } else { }".len();
913 if let ast::ExprKind::Block(ref else_node) = else_block.node {
914 if !is_simple_block(self.block, None, context.codemap)
915 || !is_simple_block(else_node, None, context.codemap)
916 || pat_expr_str.contains('\n')
921 let new_width = width.checked_sub(pat_expr_str.len() + fixed_cost)?;
922 let expr = &self.block.stmts[0];
923 let if_str = expr.rewrite(context, Shape::legacy(new_width, Indent::empty()))?;
925 let new_width = new_width.checked_sub(if_str.len())?;
926 let else_expr = &else_node.stmts[0];
927 let else_str = else_expr.rewrite(context, Shape::legacy(new_width, Indent::empty()))?;
929 if if_str.contains('\n') || else_str.contains('\n') {
933 let result = format!(
934 "{} {} {{ {} }} else {{ {} }}",
935 self.keyword, pat_expr_str, if_str, else_str
938 if result.len() <= width {
947 impl<'a> ControlFlow<'a> {
950 context: &RewriteContext,
954 ) -> Option<String> {
955 debug!("rewrite_pat_expr {:?} {:?} {:?}", shape, self.pats, expr);
957 let cond_shape = shape.offset_left(offset)?;
958 if !self.pats.is_empty() {
959 let matcher = if self.matcher.is_empty() {
960 self.matcher.to_owned()
962 format!("{} ", self.matcher)
964 let pat_shape = cond_shape
965 .offset_left(matcher.len())?
966 .sub_width(self.connector.len())?;
967 let pat_string = rewrite_multiple_patterns(context, &self.pats, pat_shape)?;
968 let result = format!("{}{}{}", matcher, pat_string, self.connector);
969 return rewrite_assign_rhs(context, result, expr, cond_shape);
972 let expr_rw = expr.rewrite(context, cond_shape);
973 // The expression may (partially) fit on the current line.
974 // We do not allow splitting between `if` and condition.
975 if self.keyword == "if" || expr_rw.is_some() {
979 // The expression won't fit on the current line, jump to next.
980 let nested_shape = shape
981 .block_indent(context.config.tab_spaces())
982 .with_max_width(context.config);
983 let nested_indent_str = nested_shape.indent.to_string_with_newline(context.config);
984 expr.rewrite(context, nested_shape)
985 .map(|expr_rw| format!("{}{}", nested_indent_str, expr_rw))
990 context: &RewriteContext,
993 ) -> Option<(String, usize)> {
994 // Do not take the rhs overhead from the upper expressions into account
995 // when rewriting pattern.
996 let new_width = context.budget(shape.used_width());
997 let fresh_shape = Shape {
1001 let constr_shape = if self.nested_if {
1002 // We are part of an if-elseif-else chain. Our constraints are tightened.
1003 // 7 = "} else " .len()
1004 fresh_shape.offset_left(7)?
1009 let label_string = rewrite_label(self.label);
1010 // 1 = space after keyword.
1011 let offset = self.keyword.len() + label_string.len() + 1;
1013 let pat_expr_string = match self.cond {
1014 Some(cond) => self.rewrite_pat_expr(context, cond, constr_shape, offset)?,
1015 None => String::new(),
1018 let brace_overhead =
1019 if context.config.control_brace_style() != ControlBraceStyle::AlwaysNextLine {
1025 let one_line_budget = context
1028 .checked_sub(constr_shape.used_width() + offset + brace_overhead)
1030 let force_newline_brace = (pat_expr_string.contains('\n')
1031 || pat_expr_string.len() > one_line_budget)
1032 && !last_line_extendable(&pat_expr_string);
1034 // Try to format if-else on single line.
1035 if self.allow_single_line
1039 .single_line_if_else_max_width > 0
1041 let trial = self.rewrite_single_line(&pat_expr_string, context, shape.width);
1043 if let Some(cond_str) = trial {
1048 .single_line_if_else_max_width
1050 return Some((cond_str, 0));
1055 let cond_span = if let Some(cond) = self.cond {
1058 mk_sp(self.block.span.lo(), self.block.span.lo())
1061 // `for event in event`
1062 // Do not include label in the span.
1063 let lo = self.label.map_or(self.span.lo(), |label| label.span.hi());
1064 let between_kwd_cond = mk_sp(
1067 .span_after(mk_sp(lo, self.span.hi()), self.keyword.trim()),
1068 if self.pats.is_empty() {
1070 } else if self.matcher.is_empty() {
1071 self.pats[0].span.lo()
1075 .span_before(self.span, self.matcher.trim())
1079 let between_kwd_cond_comment = extract_comment(between_kwd_cond, context, shape);
1081 let after_cond_comment =
1082 extract_comment(mk_sp(cond_span.hi(), self.block.span.lo()), context, shape);
1084 let block_sep = if self.cond.is_none() && between_kwd_cond_comment.is_some() {
1086 } else if context.config.control_brace_style() == ControlBraceStyle::AlwaysNextLine
1087 || force_newline_brace
1094 let used_width = if pat_expr_string.contains('\n') {
1095 last_line_width(&pat_expr_string)
1097 // 2 = spaces after keyword and condition.
1098 label_string.len() + self.keyword.len() + pat_expr_string.len() + 2
1106 between_kwd_cond_comment.as_ref().map_or(
1107 if pat_expr_string.is_empty() || pat_expr_string.starts_with('\n') {
1115 after_cond_comment.as_ref().map_or(block_sep, |s| &**s)
1122 impl<'a> Rewrite for ControlFlow<'a> {
1123 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
1124 debug!("ControlFlow::rewrite {:?} {:?}", self, shape);
1126 let alt_block_sep = &shape.indent.to_string_with_newline(context.config);
1127 let (cond_str, used_width) = self.rewrite_cond(context, shape, alt_block_sep)?;
1128 // If `used_width` is 0, it indicates that whole control flow is written in a single line.
1129 if used_width == 0 {
1130 return Some(cond_str);
1133 let block_width = shape.width.checked_sub(used_width).unwrap_or(0);
1134 // This is used only for the empty block case: `{}`. So, we use 1 if we know
1135 // we should avoid the single line case.
1136 let block_width = if self.else_block.is_some() || self.nested_if {
1141 let block_shape = Shape {
1145 let mut block_context = context.clone();
1146 block_context.is_if_else_block = self.else_block.is_some();
1148 rewrite_block_with_visitor(&block_context, "", self.block, None, block_shape, true)?;
1150 let mut result = format!("{}{}", cond_str, block_str);
1152 if let Some(else_block) = self.else_block {
1153 let shape = Shape::indented(shape.indent, context.config);
1154 let mut last_in_chain = false;
1155 let rewrite = match else_block.node {
1156 // If the else expression is another if-else expression, prevent it
1157 // from being formatted on a single line.
1158 // Note how we're passing the original shape, as the
1159 // cost of "else" should not cascade.
1160 ast::ExprKind::IfLet(ref pat, ref cond, ref if_block, ref next_else_block) => {
1161 ControlFlow::new_if(
1163 ptr_vec_to_ref_vec(pat),
1165 next_else_block.as_ref().map(|e| &**e),
1168 mk_sp(else_block.span.lo(), self.span.hi()),
1169 ).rewrite(context, shape)
1171 ast::ExprKind::If(ref cond, ref if_block, ref next_else_block) => {
1172 ControlFlow::new_if(
1176 next_else_block.as_ref().map(|e| &**e),
1179 mk_sp(else_block.span.lo(), self.span.hi()),
1180 ).rewrite(context, shape)
1183 last_in_chain = true;
1184 // When rewriting a block, the width is only used for single line
1185 // blocks, passing 1 lets us avoid that.
1186 let else_shape = Shape {
1187 width: min(1, shape.width),
1190 format_expr(else_block, ExprType::Statement, context, else_shape)
1194 let between_kwd_else_block = mk_sp(
1195 self.block.span.hi(),
1198 .span_before(mk_sp(self.block.span.hi(), else_block.span.lo()), "else"),
1200 let between_kwd_else_block_comment =
1201 extract_comment(between_kwd_else_block, context, shape);
1203 let after_else = mk_sp(
1206 .span_after(mk_sp(self.block.span.hi(), else_block.span.lo()), "else"),
1207 else_block.span.lo(),
1209 let after_else_comment = extract_comment(after_else, context, shape);
1211 let between_sep = match context.config.control_brace_style() {
1212 ControlBraceStyle::AlwaysNextLine | ControlBraceStyle::ClosingNextLine => {
1215 ControlBraceStyle::AlwaysSameLine => " ",
1217 let after_sep = match context.config.control_brace_style() {
1218 ControlBraceStyle::AlwaysNextLine if last_in_chain => &*alt_block_sep,
1222 result.push_str(&format!(
1224 between_kwd_else_block_comment
1226 .map_or(between_sep, |s| &**s),
1227 after_else_comment.as_ref().map_or(after_sep, |s| &**s),
1229 result.push_str(&rewrite?);
1236 fn rewrite_label(opt_label: Option<ast::Label>) -> Cow<'static, str> {
1238 Some(label) => Cow::from(format!("{}: ", label.ident)),
1239 None => Cow::from(""),
1243 fn extract_comment(span: Span, context: &RewriteContext, shape: Shape) -> Option<String> {
1244 match rewrite_missing_comment(span, shape, context) {
1245 Some(ref comment) if !comment.is_empty() => Some(format!(
1246 "{indent}{}{indent}",
1248 indent = shape.indent.to_string_with_newline(context.config)
1254 pub fn block_contains_comment(block: &ast::Block, codemap: &CodeMap) -> bool {
1255 let snippet = codemap.span_to_snippet(block.span).unwrap();
1256 contains_comment(&snippet)
1259 // Checks that a block contains no statements, an expression and no comments or
1261 // FIXME: incorrectly returns false when comment is contained completely within
1263 pub fn is_simple_block(
1265 attrs: Option<&[ast::Attribute]>,
1268 (block.stmts.len() == 1 && stmt_is_expr(&block.stmts[0])
1269 && !block_contains_comment(block, codemap) && attrs.map_or(true, |a| a.is_empty()))
1272 /// Checks whether a block contains at most one statement or expression, and no
1273 /// comments or attributes.
1274 pub fn is_simple_block_stmt(
1276 attrs: Option<&[ast::Attribute]>,
1279 block.stmts.len() <= 1 && !block_contains_comment(block, codemap)
1280 && attrs.map_or(true, |a| a.is_empty())
1283 /// Checks whether a block contains no statements, expressions, comments, or
1284 /// inner attributes.
1285 pub fn is_empty_block(
1287 attrs: Option<&[ast::Attribute]>,
1290 block.stmts.is_empty() && !block_contains_comment(block, codemap)
1291 && attrs.map_or(true, |a| inner_attributes(a).is_empty())
1294 pub fn stmt_is_expr(stmt: &ast::Stmt) -> bool {
1296 ast::StmtKind::Expr(..) => true,
1301 pub fn is_unsafe_block(block: &ast::Block) -> bool {
1302 if let ast::BlockCheckMode::Unsafe(..) = block.rules {
1309 pub fn rewrite_multiple_patterns(
1310 context: &RewriteContext,
1313 ) -> Option<String> {
1314 let pat_strs = pats.iter()
1315 .map(|p| p.rewrite(context, shape))
1316 .collect::<Option<Vec<_>>>()?;
1318 let use_mixed_layout = pats.iter()
1319 .zip(pat_strs.iter())
1320 .all(|(pat, pat_str)| is_short_pattern(pat, pat_str));
1321 let items: Vec<_> = pat_strs.into_iter().map(ListItem::from_str).collect();
1322 let tactic = if use_mixed_layout {
1323 DefinitiveListTactic::Mixed
1327 ListTactic::HorizontalVertical,
1328 Separator::VerticalBar,
1332 let fmt = ListFormatting {
1335 trailing_separator: SeparatorTactic::Never,
1336 separator_place: context.config.binop_separator(),
1338 ends_with_newline: false,
1339 preserve_newline: false,
1340 config: context.config,
1342 write_list(&items, &fmt)
1345 pub fn rewrite_literal(context: &RewriteContext, l: &ast::Lit, shape: Shape) -> Option<String> {
1347 ast::LitKind::Str(_, ast::StrStyle::Cooked) => rewrite_string_lit(context, l.span, shape),
1349 context.snippet(l.span).to_owned(),
1350 context.config.max_width(),
1356 fn rewrite_string_lit(context: &RewriteContext, span: Span, shape: Shape) -> Option<String> {
1357 let string_lit = context.snippet(span);
1359 if !context.config.format_strings() {
1364 .all(|line| line.ends_with('\\'))
1366 let new_indent = shape.visual_indent(1).indent;
1367 let indented_string_lit = String::from(
1373 new_indent.to_string(context.config),
1377 .collect::<Vec<_>>()
1381 return wrap_str(indented_string_lit, context.config.max_width(), shape);
1383 return wrap_str(string_lit.to_owned(), context.config.max_width(), shape);
1387 // Remove the quote characters.
1388 let str_lit = &string_lit[1..string_lit.len() - 1];
1392 &StringFormat::new(shape.visual_indent(0), context.config),
1397 /// In case special-case style is required, returns an offset from which we start horizontal layout.
1398 pub fn maybe_get_args_offset<T: ToExpr>(callee_str: &str, args: &[&T]) -> Option<(bool, usize)> {
1399 if let Some(&(_, num_args_before)) = SPECIAL_MACRO_WHITELIST
1401 .find(|&&(s, _)| s == callee_str)
1403 let all_simple = args.len() > num_args_before && is_every_expr_simple(args);
1405 Some((all_simple, num_args_before))
1411 /// A list of `format!`-like macros, that take a long format string and a list of arguments to
1414 /// Organized as a list of `(&str, usize)` tuples, giving the name of the macro and the number of
1415 /// arguments before the format string (none for `format!("format", ...)`, one for `assert!(result,
1416 /// "format", ...)`, two for `assert_eq!(left, right, "format", ...)`).
1417 const SPECIAL_MACRO_WHITELIST: &[(&str, usize)] = &[
1418 // format! like macros
1419 // From the Rust Standard Library.
1423 ("format_args!", 0),
1427 ("unreachable!", 0),
1428 // From the `log` crate.
1433 // write! like macros
1435 ("debug_assert!", 1),
1438 // assert_eq! like macros
1441 ("debug_assert_eq!", 2),
1442 ("debug_assert_ne!", 2),
1445 pub fn rewrite_call(
1446 context: &RewriteContext,
1448 args: &[ptr::P<ast::Expr>],
1451 ) -> Option<String> {
1452 overflow::rewrite_with_parens(
1455 &ptr_vec_to_ref_vec(args),
1458 context.config.width_heuristics().fn_call_width,
1459 if context.inside_macro {
1460 if span_ends_with_comma(context, span) {
1461 Some(SeparatorTactic::Always)
1463 Some(SeparatorTactic::Never)
1471 fn is_simple_expr(expr: &ast::Expr) -> bool {
1473 ast::ExprKind::Lit(..) => true,
1474 ast::ExprKind::Path(ref qself, ref path) => qself.is_none() && path.segments.len() <= 1,
1475 ast::ExprKind::AddrOf(_, ref expr)
1476 | ast::ExprKind::Box(ref expr)
1477 | ast::ExprKind::Cast(ref expr, _)
1478 | ast::ExprKind::Field(ref expr, _)
1479 | ast::ExprKind::Try(ref expr)
1480 | ast::ExprKind::TupField(ref expr, _)
1481 | ast::ExprKind::Unary(_, ref expr) => is_simple_expr(expr),
1482 ast::ExprKind::Index(ref lhs, ref rhs) | ast::ExprKind::Repeat(ref lhs, ref rhs) => {
1483 is_simple_expr(lhs) && is_simple_expr(rhs)
1489 fn is_every_expr_simple<T: ToExpr>(lists: &[&T]) -> bool {
1492 .all(|arg| arg.to_expr().map_or(false, is_simple_expr))
1495 pub fn can_be_overflowed_expr(context: &RewriteContext, expr: &ast::Expr, args_len: usize) -> bool {
1497 ast::ExprKind::Match(..) => {
1498 (context.use_block_indent() && args_len == 1)
1499 || (context.config.indent_style() == IndentStyle::Visual && args_len > 1)
1501 ast::ExprKind::If(..)
1502 | ast::ExprKind::IfLet(..)
1503 | ast::ExprKind::ForLoop(..)
1504 | ast::ExprKind::Loop(..)
1505 | ast::ExprKind::While(..)
1506 | ast::ExprKind::WhileLet(..) => {
1507 context.config.combine_control_expr() && context.use_block_indent() && args_len == 1
1509 ast::ExprKind::Block(..) | ast::ExprKind::Closure(..) => {
1510 context.use_block_indent()
1511 || context.config.indent_style() == IndentStyle::Visual && args_len > 1
1513 ast::ExprKind::Array(..)
1514 | ast::ExprKind::Call(..)
1515 | ast::ExprKind::Mac(..)
1516 | ast::ExprKind::MethodCall(..)
1517 | ast::ExprKind::Struct(..)
1518 | ast::ExprKind::Tup(..) => context.use_block_indent() && args_len == 1,
1519 ast::ExprKind::AddrOf(_, ref expr)
1520 | ast::ExprKind::Box(ref expr)
1521 | ast::ExprKind::Try(ref expr)
1522 | ast::ExprKind::Unary(_, ref expr)
1523 | ast::ExprKind::Cast(ref expr, _) => can_be_overflowed_expr(context, expr, args_len),
1528 pub fn is_nested_call(expr: &ast::Expr) -> bool {
1530 ast::ExprKind::Call(..) | ast::ExprKind::Mac(..) => true,
1531 ast::ExprKind::AddrOf(_, ref expr)
1532 | ast::ExprKind::Box(ref expr)
1533 | ast::ExprKind::Try(ref expr)
1534 | ast::ExprKind::Unary(_, ref expr)
1535 | ast::ExprKind::Cast(ref expr, _) => is_nested_call(expr),
1540 /// Return true if a function call or a method call represented by the given span ends with a
1541 /// trailing comma. This function is used when rewriting macro, as adding or removing a trailing
1542 /// comma from macro can potentially break the code.
1543 pub fn span_ends_with_comma(context: &RewriteContext, span: Span) -> bool {
1544 let mut result: bool = Default::default();
1545 let mut prev_char: char = Default::default();
1547 for (kind, c) in CharClasses::new(context.snippet(span).chars()) {
1549 _ if kind.is_comment() || c.is_whitespace() => continue,
1550 ')' | '}' => result = result && prev_char != c,
1551 ',' => result = true,
1552 _ => result = false,
1561 context: &RewriteContext,
1562 mut subexpr: &ast::Expr,
1565 ) -> Option<String> {
1566 debug!("rewrite_paren, shape: {:?}", shape);
1568 // Extract comments within parens.
1569 let mut pre_comment;
1570 let mut post_comment;
1573 let pre_span = mk_sp(span.lo() + BytePos(1), subexpr.span.lo());
1574 let post_span = mk_sp(subexpr.span.hi(), span.hi() - BytePos(1));
1575 pre_comment = rewrite_missing_comment(pre_span, shape, context)?;
1576 post_comment = rewrite_missing_comment(post_span, shape, context)?;
1578 // Remove nested parens if there are no comments.
1579 if let ast::ExprKind::Paren(ref subsubexpr) = subexpr.node {
1580 if pre_comment.is_empty() && post_comment.is_empty() {
1581 span = subexpr.span;
1582 subexpr = subsubexpr;
1590 let total_paren_overhead = paren_overhead(context);
1591 let paren_overhead = total_paren_overhead / 2;
1592 let sub_shape = shape
1593 .offset_left(paren_overhead)
1594 .and_then(|s| s.sub_width(paren_overhead))?;
1596 let paren_wrapper = |s: &str| {
1597 if context.config.spaces_within_parens_and_brackets() && !s.is_empty() {
1598 format!("( {}{}{} )", pre_comment, s, post_comment)
1600 format!("({}{}{})", pre_comment, s, post_comment)
1604 let subexpr_str = subexpr.rewrite(context, sub_shape)?;
1605 debug!("rewrite_paren, subexpr_str: `{:?}`", subexpr_str);
1607 if subexpr_str.contains('\n')
1608 || first_line_width(&subexpr_str) + total_paren_overhead <= shape.width
1610 Some(paren_wrapper(&subexpr_str))
1619 context: &RewriteContext,
1621 ) -> Option<String> {
1622 let expr_str = expr.rewrite(context, shape)?;
1624 let (lbr, rbr) = if context.config.spaces_within_parens_and_brackets() {
1630 let offset = last_line_width(&expr_str) + lbr.len();
1631 let rhs_overhead = shape.rhs_overhead(context.config);
1632 let index_shape = if expr_str.contains('\n') {
1633 Shape::legacy(context.config.max_width(), shape.indent)
1634 .offset_left(offset)
1635 .and_then(|shape| shape.sub_width(rbr.len() + rhs_overhead))
1637 shape.visual_indent(offset).sub_width(offset + rbr.len())
1639 let orig_index_rw = index_shape.and_then(|s| index.rewrite(context, s));
1641 // Return if index fits in a single line.
1642 match orig_index_rw {
1643 Some(ref index_str) if !index_str.contains('\n') => {
1644 return Some(format!("{}{}{}{}", expr_str, lbr, index_str, rbr));
1649 // Try putting index on the next line and see if it fits in a single line.
1650 let indent = shape.indent.block_indent(context.config);
1651 let index_shape = Shape::indented(indent, context.config).offset_left(lbr.len())?;
1652 let index_shape = index_shape.sub_width(rbr.len() + rhs_overhead)?;
1653 let new_index_rw = index.rewrite(context, index_shape);
1654 match (orig_index_rw, new_index_rw) {
1655 (_, Some(ref new_index_str)) if !new_index_str.contains('\n') => Some(format!(
1658 indent.to_string_with_newline(context.config),
1663 (None, Some(ref new_index_str)) => Some(format!(
1666 indent.to_string_with_newline(context.config),
1671 (Some(ref index_str), _) => Some(format!("{}{}{}{}", expr_str, lbr, index_str, rbr)),
1676 fn struct_lit_can_be_aligned(fields: &[ast::Field], base: &Option<&ast::Expr>) -> bool {
1681 fields.iter().all(|field| !field.is_shorthand)
1684 fn rewrite_struct_lit<'a>(
1685 context: &RewriteContext,
1687 fields: &'a [ast::Field],
1688 base: Option<&'a ast::Expr>,
1691 ) -> Option<String> {
1692 debug!("rewrite_struct_lit: shape {:?}", shape);
1694 enum StructLitField<'a> {
1695 Regular(&'a ast::Field),
1696 Base(&'a ast::Expr),
1700 let path_shape = shape.sub_width(2)?;
1701 let path_str = rewrite_path(context, PathContext::Expr, None, path, path_shape)?;
1703 if fields.is_empty() && base.is_none() {
1704 return Some(format!("{} {{}}", path_str));
1707 // Foo { a: Foo } - indent is +3, width is -5.
1708 let (h_shape, v_shape) = struct_lit_shape(shape, context, path_str.len() + 3, 2)?;
1710 let one_line_width = h_shape.map_or(0, |shape| shape.width);
1711 let body_lo = context.snippet_provider.span_after(span, "{");
1712 let fields_str = if struct_lit_can_be_aligned(fields, &base)
1713 && context.config.struct_field_align_threshold() > 0
1715 rewrite_with_alignment(
1719 mk_sp(body_lo, span.hi()),
1723 let field_iter = fields
1725 .map(StructLitField::Regular)
1726 .chain(base.into_iter().map(StructLitField::Base));
1728 let span_lo = |item: &StructLitField| match *item {
1729 StructLitField::Regular(field) => field.span().lo(),
1730 StructLitField::Base(expr) => {
1731 let last_field_hi = fields.last().map_or(span.lo(), |field| field.span.hi());
1732 let snippet = context.snippet(mk_sp(last_field_hi, expr.span.lo()));
1733 let pos = snippet.find_uncommented("..").unwrap();
1734 last_field_hi + BytePos(pos as u32)
1737 let span_hi = |item: &StructLitField| match *item {
1738 StructLitField::Regular(field) => field.span().hi(),
1739 StructLitField::Base(expr) => expr.span.hi(),
1741 let rewrite = |item: &StructLitField| match *item {
1742 StructLitField::Regular(field) => {
1743 // The 1 taken from the v_budget is for the comma.
1744 rewrite_field(context, field, v_shape.sub_width(1)?, 0)
1746 StructLitField::Base(expr) => {
1748 expr.rewrite(context, v_shape.offset_left(2)?)
1749 .map(|s| format!("..{}", s))
1753 let items = itemize_list(
1754 context.snippet_provider,
1765 let item_vec = items.collect::<Vec<_>>();
1767 let tactic = struct_lit_tactic(h_shape, context, &item_vec);
1768 let nested_shape = shape_for_tactic(tactic, h_shape, v_shape);
1770 let ends_with_comma = span_ends_with_comma(context, span);
1771 let force_no_trailing_comma = if context.inside_macro && !ends_with_comma {
1777 let fmt = struct_lit_formatting(
1781 force_no_trailing_comma || base.is_some(),
1784 write_list(&item_vec, &fmt)?
1787 let fields_str = wrap_struct_field(context, &fields_str, shape, v_shape, one_line_width);
1788 Some(format!("{} {{{}}}", path_str, fields_str))
1790 // FIXME if context.config.indent_style() == Visual, but we run out
1791 // of space, we should fall back to BlockIndent.
1794 pub fn wrap_struct_field(
1795 context: &RewriteContext,
1798 nested_shape: Shape,
1799 one_line_width: usize,
1801 if context.config.indent_style() == IndentStyle::Block
1802 && (fields_str.contains('\n') || !context.config.struct_lit_single_line()
1803 || fields_str.len() > one_line_width)
1807 nested_shape.indent.to_string_with_newline(context.config),
1809 shape.indent.to_string_with_newline(context.config)
1812 // One liner or visual indent.
1813 format!(" {} ", fields_str)
1817 pub fn struct_lit_field_separator(config: &Config) -> &str {
1818 colon_spaces(config.space_before_colon(), config.space_after_colon())
1821 pub fn rewrite_field(
1822 context: &RewriteContext,
1825 prefix_max_width: usize,
1826 ) -> Option<String> {
1827 if contains_skip(&field.attrs) {
1828 return Some(context.snippet(field.span()).to_owned());
1830 let mut attrs_str = field.attrs.rewrite(context, shape)?;
1831 if !attrs_str.is_empty() {
1832 attrs_str.push_str(&shape.indent.to_string_with_newline(context.config));
1834 let name = field.ident.node.to_string();
1835 if field.is_shorthand {
1836 Some(attrs_str + &name)
1838 let mut separator = String::from(struct_lit_field_separator(context.config));
1839 for _ in 0..prefix_max_width.checked_sub(name.len()).unwrap_or(0) {
1840 separator.push(' ');
1842 let overhead = name.len() + separator.len();
1843 let expr_shape = shape.offset_left(overhead)?;
1844 let expr = field.expr.rewrite(context, expr_shape);
1847 Some(ref e) if e.as_str() == name && context.config.use_field_init_shorthand() => {
1848 Some(attrs_str + &name)
1850 Some(e) => Some(format!("{}{}{}{}", attrs_str, name, separator, e)),
1852 let expr_offset = shape.indent.block_indent(context.config);
1855 .rewrite(context, Shape::indented(expr_offset, context.config));
1861 expr_offset.to_string(context.config),
1870 fn rewrite_tuple_in_visual_indent_style<'a, T>(
1871 context: &RewriteContext,
1877 T: Rewrite + Spanned + ToExpr + 'a,
1879 let mut items = items.iter();
1880 // In case of length 1, need a trailing comma
1881 debug!("rewrite_tuple_in_visual_indent_style {:?}", shape);
1882 if items.len() == 1 {
1884 let nested_shape = shape.sub_width(3)?.visual_indent(1);
1888 .rewrite(context, nested_shape)
1890 if context.config.spaces_within_parens_and_brackets() {
1891 format!("( {}, )", s)
1898 let list_lo = context.snippet_provider.span_after(span, "(");
1899 let nested_shape = shape.sub_width(2)?.visual_indent(1);
1900 let items = itemize_list(
1901 context.snippet_provider,
1905 |item| item.span().lo(),
1906 |item| item.span().hi(),
1907 |item| item.rewrite(context, nested_shape),
1909 span.hi() - BytePos(1),
1912 let item_vec: Vec<_> = items.collect();
1913 let tactic = definitive_tactic(
1915 ListTactic::HorizontalVertical,
1919 let fmt = ListFormatting {
1922 trailing_separator: SeparatorTactic::Never,
1923 separator_place: SeparatorPlace::Back,
1925 ends_with_newline: false,
1926 preserve_newline: false,
1927 config: context.config,
1929 let list_str = write_list(&item_vec, &fmt)?;
1931 if context.config.spaces_within_parens_and_brackets() && !list_str.is_empty() {
1932 Some(format!("( {} )", list_str))
1934 Some(format!("({})", list_str))
1938 pub fn rewrite_tuple<'a, T>(
1939 context: &RewriteContext,
1945 T: Rewrite + Spanned + ToExpr + 'a,
1947 debug!("rewrite_tuple {:?}", shape);
1948 if context.use_block_indent() {
1949 // We use the same rule as function calls for rewriting tuples.
1950 let force_tactic = if context.inside_macro {
1951 if span_ends_with_comma(context, span) {
1952 Some(SeparatorTactic::Always)
1954 Some(SeparatorTactic::Never)
1957 if items.len() == 1 {
1958 Some(SeparatorTactic::Always)
1963 overflow::rewrite_with_parens(
1969 context.config.width_heuristics().fn_call_width,
1973 rewrite_tuple_in_visual_indent_style(context, items, span, shape)
1977 pub fn rewrite_unary_prefix<R: Rewrite>(
1978 context: &RewriteContext,
1982 ) -> Option<String> {
1984 .rewrite(context, shape.offset_left(prefix.len())?)
1985 .map(|r| format!("{}{}", prefix, r))
1988 // FIXME: this is probably not correct for multi-line Rewrites. we should
1989 // subtract suffix.len() from the last line budget, not the first!
1990 pub fn rewrite_unary_suffix<R: Rewrite>(
1991 context: &RewriteContext,
1995 ) -> Option<String> {
1997 .rewrite(context, shape.sub_width(suffix.len())?)
2004 fn rewrite_unary_op(
2005 context: &RewriteContext,
2009 ) -> Option<String> {
2010 // For some reason, an UnOp is not spanned like BinOp!
2011 let operator_str = match *op {
2012 ast::UnOp::Deref => "*",
2013 ast::UnOp::Not => "!",
2014 ast::UnOp::Neg => "-",
2016 rewrite_unary_prefix(context, operator_str, expr, shape)
2019 fn rewrite_assignment(
2020 context: &RewriteContext,
2023 op: Option<&ast::BinOp>,
2025 ) -> Option<String> {
2026 let operator_str = match op {
2027 Some(op) => context.snippet(op.span),
2031 // 1 = space between lhs and operator.
2032 let lhs_shape = shape.sub_width(operator_str.len() + 1)?;
2033 let lhs_str = format!("{} {}", lhs.rewrite(context, lhs_shape)?, operator_str);
2035 rewrite_assign_rhs(context, lhs_str, rhs, shape)
2038 /// Controls where to put the rhs.
2039 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
2040 pub enum RhsTactics {
2043 /// Put the rhs on the next line if it uses multiple line.
2047 // The left hand side must contain everything up to, and including, the
2048 // assignment operator.
2049 pub fn rewrite_assign_rhs<S: Into<String>, R: Rewrite>(
2050 context: &RewriteContext,
2054 ) -> Option<String> {
2055 rewrite_assign_rhs_with(context, lhs, ex, shape, RhsTactics::Default)
2058 pub fn rewrite_assign_rhs_with<S: Into<String>, R: Rewrite>(
2059 context: &RewriteContext,
2063 rhs_tactics: RhsTactics,
2064 ) -> Option<String> {
2065 let lhs = lhs.into();
2066 let last_line_width = last_line_width(&lhs)
2067 .checked_sub(if lhs.contains('\n') {
2068 shape.indent.width()
2073 // 1 = space between operator and rhs.
2074 let orig_shape = shape.offset_left(last_line_width + 1).unwrap_or(Shape {
2076 offset: shape.offset + last_line_width + 1,
2079 let rhs = choose_rhs(
2083 ex.rewrite(context, orig_shape),
2089 fn choose_rhs<R: Rewrite>(
2090 context: &RewriteContext,
2093 orig_rhs: Option<String>,
2094 rhs_tactics: RhsTactics,
2095 ) -> Option<String> {
2097 Some(ref new_str) if !new_str.contains('\n') && new_str.len() <= shape.width => {
2098 Some(format!(" {}", new_str))
2101 // Expression did not fit on the same line as the identifier.
2102 // Try splitting the line and see if that works better.
2104 Shape::indented(shape.indent.block_indent(context.config), context.config)
2105 .sub_width(shape.rhs_overhead(context.config))?;
2106 let new_rhs = expr.rewrite(context, new_shape);
2107 let new_indent_str = &new_shape.indent.to_string_with_newline(context.config);
2109 match (orig_rhs, new_rhs) {
2110 (Some(ref orig_rhs), Some(ref new_rhs))
2111 if wrap_str(new_rhs.clone(), context.config.max_width(), new_shape)
2114 Some(format!(" {}", orig_rhs))
2116 (Some(ref orig_rhs), Some(ref new_rhs))
2117 if prefer_next_line(orig_rhs, new_rhs, rhs_tactics) =>
2119 Some(format!("{}{}", new_indent_str, new_rhs))
2121 (None, Some(ref new_rhs)) => Some(format!("{}{}", new_indent_str, new_rhs)),
2122 (None, None) => None,
2123 (Some(ref orig_rhs), _) => Some(format!(" {}", orig_rhs)),
2129 pub fn prefer_next_line(orig_rhs: &str, next_line_rhs: &str, rhs_tactics: RhsTactics) -> bool {
2130 rhs_tactics == RhsTactics::ForceNextLine || !next_line_rhs.contains('\n')
2131 || count_newlines(orig_rhs) > count_newlines(next_line_rhs) + 1
2134 fn rewrite_expr_addrof(
2135 context: &RewriteContext,
2136 mutability: ast::Mutability,
2139 ) -> Option<String> {
2140 let operator_str = match mutability {
2141 ast::Mutability::Immutable => "&",
2142 ast::Mutability::Mutable => "&mut ",
2144 rewrite_unary_prefix(context, operator_str, expr, shape)
2148 fn to_expr(&self) -> Option<&ast::Expr>;
2149 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool;
2152 impl ToExpr for ast::Expr {
2153 fn to_expr(&self) -> Option<&ast::Expr> {
2157 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool {
2158 can_be_overflowed_expr(context, self, len)
2162 impl ToExpr for ast::Ty {
2163 fn to_expr(&self) -> Option<&ast::Expr> {
2167 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool {
2168 can_be_overflowed_type(context, self, len)
2172 impl<'a> ToExpr for TuplePatField<'a> {
2173 fn to_expr(&self) -> Option<&ast::Expr> {
2177 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool {
2178 can_be_overflowed_pat(context, self, len)
2182 impl<'a> ToExpr for ast::StructField {
2183 fn to_expr(&self) -> Option<&ast::Expr> {
2187 fn can_be_overflowed(&self, _: &RewriteContext, _: usize) -> bool {
2192 impl<'a> ToExpr for MacroArg {
2193 fn to_expr(&self) -> Option<&ast::Expr> {
2195 MacroArg::Expr(ref expr) => Some(expr),
2200 fn can_be_overflowed(&self, context: &RewriteContext, len: usize) -> bool {
2202 MacroArg::Expr(ref expr) => can_be_overflowed_expr(context, expr, len),
2203 MacroArg::Ty(ref ty) => can_be_overflowed_type(context, ty, len),
2204 MacroArg::Pat(..) => false,
2205 MacroArg::Item(..) => len == 1,
2210 impl ToExpr for ast::GenericParam {
2211 fn to_expr(&self) -> Option<&ast::Expr> {
2215 fn can_be_overflowed(&self, _: &RewriteContext, _: usize) -> bool {