| // Formatting top-level items - functions, structs, enums, traits, impls. |
| |
| use std::borrow::Cow; |
| use std::cmp::{max, min, Ordering}; |
| |
| use regex::Regex; |
| use rustc_ast::visit; |
| use rustc_ast::{ast, ptr}; |
| use rustc_span::{symbol, BytePos, Span, DUMMY_SP}; |
| |
| use crate::attr::filter_inline_attrs; |
| use crate::comment::{ |
| combine_strs_with_missing_comments, contains_comment, is_last_comment_block, |
| recover_comment_removed, recover_missing_comment_in_span, rewrite_missing_comment, |
| FindUncommented, |
| }; |
| use crate::config::lists::*; |
| use crate::config::{BraceStyle, Config, IndentStyle, Version}; |
| use crate::expr::{ |
| is_empty_block, is_simple_block_stmt, rewrite_assign_rhs, rewrite_assign_rhs_with, |
| rewrite_assign_rhs_with_comments, rewrite_else_kw_with_comments, rewrite_let_else_block, |
| RhsAssignKind, RhsTactics, |
| }; |
| use crate::lists::{definitive_tactic, itemize_list, write_list, ListFormatting, Separator}; |
| use crate::macros::{rewrite_macro, MacroPosition}; |
| use crate::overflow; |
| use crate::rewrite::{Rewrite, RewriteContext}; |
| use crate::shape::{Indent, Shape}; |
| use crate::source_map::{LineRangeUtils, SpanUtils}; |
| use crate::spanned::Spanned; |
| use crate::stmt::Stmt; |
| use crate::types::opaque_ty; |
| use crate::utils::*; |
| use crate::vertical::rewrite_with_alignment; |
| use crate::visitor::FmtVisitor; |
| |
| const DEFAULT_VISIBILITY: ast::Visibility = ast::Visibility { |
| kind: ast::VisibilityKind::Inherited, |
| span: DUMMY_SP, |
| tokens: None, |
| }; |
| |
| fn type_annotation_separator(config: &Config) -> &str { |
| colon_spaces(config) |
| } |
| |
| // Statements of the form |
| // let pat: ty = init; or let pat: ty = init else { .. }; |
| impl Rewrite for ast::Local { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| debug!( |
| "Local::rewrite {:?} {} {:?}", |
| self, shape.width, shape.indent |
| ); |
| |
| skip_out_of_file_lines_range!(context, self.span); |
| |
| if contains_skip(&self.attrs) { |
| return None; |
| } |
| |
| let attrs_str = self.attrs.rewrite(context, shape)?; |
| let mut result = if attrs_str.is_empty() { |
| "let ".to_owned() |
| } else { |
| combine_strs_with_missing_comments( |
| context, |
| &attrs_str, |
| "let ", |
| mk_sp( |
| self.attrs.last().map(|a| a.span.hi()).unwrap(), |
| self.span.lo(), |
| ), |
| shape, |
| false, |
| )? |
| }; |
| let let_kw_offset = result.len() - "let ".len(); |
| |
| // 4 = "let ".len() |
| let pat_shape = shape.offset_left(4)?; |
| // 1 = ; |
| let pat_shape = pat_shape.sub_width(1)?; |
| let pat_str = self.pat.rewrite(context, pat_shape)?; |
| result.push_str(&pat_str); |
| |
| // String that is placed within the assignment pattern and expression. |
| let infix = { |
| let mut infix = String::with_capacity(32); |
| |
| if let Some(ref ty) = self.ty { |
| let separator = type_annotation_separator(context.config); |
| let ty_shape = if pat_str.contains('\n') { |
| shape.with_max_width(context.config) |
| } else { |
| shape |
| } |
| .offset_left(last_line_width(&result) + separator.len())? |
| // 2 = ` =` |
| .sub_width(2)?; |
| |
| let rewrite = ty.rewrite(context, ty_shape)?; |
| |
| infix.push_str(separator); |
| infix.push_str(&rewrite); |
| } |
| |
| if self.kind.init().is_some() { |
| infix.push_str(" ="); |
| } |
| |
| infix |
| }; |
| |
| result.push_str(&infix); |
| |
| if let Some((init, else_block)) = self.kind.init_else_opt() { |
| // 1 = trailing semicolon; |
| let nested_shape = shape.sub_width(1)?; |
| |
| result = rewrite_assign_rhs( |
| context, |
| result, |
| init, |
| &RhsAssignKind::Expr(&init.kind, init.span), |
| nested_shape, |
| )?; |
| |
| if let Some(block) = else_block { |
| let else_kw_span = init.span.between(block.span); |
| // Strip attributes and comments to check if newline is needed before the else |
| // keyword from the initializer part. (#5901) |
| let init_str = if context.config.version() == Version::Two { |
| &result[let_kw_offset..] |
| } else { |
| result.as_str() |
| }; |
| let force_newline_else = pat_str.contains('\n') |
| || !same_line_else_kw_and_brace(init_str, context, else_kw_span, nested_shape); |
| let else_kw = rewrite_else_kw_with_comments( |
| force_newline_else, |
| true, |
| context, |
| else_kw_span, |
| shape, |
| ); |
| result.push_str(&else_kw); |
| |
| // At this point we've written `let {pat} = {expr} else' into the buffer, and we |
| // want to calculate up front if there's room to write the divergent block on the |
| // same line. The available space varies based on indentation so we clamp the width |
| // on the smaller of `shape.width` and `single_line_let_else_max_width`. |
| let max_width = |
| std::cmp::min(shape.width, context.config.single_line_let_else_max_width()); |
| |
| // If available_space hits zero we know for sure this will be a multi-lined block |
| let assign_str_with_else_kw = if context.config.version() == Version::Two { |
| &result[let_kw_offset..] |
| } else { |
| result.as_str() |
| }; |
| let available_space = max_width.saturating_sub(assign_str_with_else_kw.len()); |
| |
| let allow_single_line = !force_newline_else |
| && available_space > 0 |
| && allow_single_line_let_else_block(assign_str_with_else_kw, block); |
| |
| let mut rw_else_block = |
| rewrite_let_else_block(block, allow_single_line, context, shape)?; |
| |
| let single_line_else = !rw_else_block.contains('\n'); |
| // +1 for the trailing `;` |
| let else_block_exceeds_width = rw_else_block.len() + 1 > available_space; |
| |
| if allow_single_line && single_line_else && else_block_exceeds_width { |
| // writing this on one line would exceed the available width |
| // so rewrite the else block over multiple lines. |
| rw_else_block = rewrite_let_else_block(block, false, context, shape)?; |
| } |
| |
| result.push_str(&rw_else_block); |
| }; |
| } |
| |
| result.push(';'); |
| Some(result) |
| } |
| } |
| |
| /// When the initializer expression is multi-lined, then the else keyword and opening brace of the |
| /// block ( i.e. "else {") should be put on the same line as the end of the initializer expression |
| /// if all the following are true: |
| /// |
| /// 1. The initializer expression ends with one or more closing parentheses, square brackets, |
| /// or braces |
| /// 2. There is nothing else on that line |
| /// 3. That line is not indented beyond the indent on the first line of the let keyword |
| fn same_line_else_kw_and_brace( |
| init_str: &str, |
| context: &RewriteContext<'_>, |
| else_kw_span: Span, |
| init_shape: Shape, |
| ) -> bool { |
| if !init_str.contains('\n') { |
| // initializer expression is single lined. The "else {" can only be placed on the same line |
| // as the initializer expression if there is enough room for it. |
| // 7 = ` else {` |
| return init_shape.width.saturating_sub(init_str.len()) >= 7; |
| } |
| |
| // 1. The initializer expression ends with one or more `)`, `]`, `}`. |
| if !init_str.ends_with([')', ']', '}']) { |
| return false; |
| } |
| |
| // 2. There is nothing else on that line |
| // For example, there are no comments |
| let else_kw_snippet = context.snippet(else_kw_span).trim(); |
| if else_kw_snippet != "else" { |
| return false; |
| } |
| |
| // 3. The last line of the initializer expression is not indented beyond the `let` keyword |
| let indent = init_shape.indent.to_string(context.config); |
| init_str |
| .lines() |
| .last() |
| .expect("initializer expression is multi-lined") |
| .strip_prefix(indent.as_ref()) |
| .map_or(false, |l| !l.starts_with(char::is_whitespace)) |
| } |
| |
| fn allow_single_line_let_else_block(result: &str, block: &ast::Block) -> bool { |
| if result.contains('\n') { |
| return false; |
| } |
| |
| if block.stmts.len() <= 1 { |
| return true; |
| } |
| |
| false |
| } |
| |
| // FIXME convert to using rewrite style rather than visitor |
| // FIXME format modules in this style |
| #[allow(dead_code)] |
| #[derive(Debug)] |
| struct Item<'a> { |
| unsafety: ast::Unsafe, |
| abi: Cow<'static, str>, |
| vis: Option<&'a ast::Visibility>, |
| body: Vec<BodyElement<'a>>, |
| span: Span, |
| } |
| |
| impl<'a> Item<'a> { |
| fn from_foreign_mod(fm: &'a ast::ForeignMod, span: Span, config: &Config) -> Item<'a> { |
| Item { |
| unsafety: fm.unsafety, |
| abi: format_extern( |
| ast::Extern::from_abi(fm.abi, DUMMY_SP), |
| config.force_explicit_abi(), |
| ), |
| vis: None, |
| body: fm |
| .items |
| .iter() |
| .map(|i| BodyElement::ForeignItem(i)) |
| .collect(), |
| span, |
| } |
| } |
| } |
| |
| #[derive(Debug)] |
| enum BodyElement<'a> { |
| // Stmt(&'a ast::Stmt), |
| // Field(&'a ast::ExprField), |
| // Variant(&'a ast::Variant), |
| // Item(&'a ast::Item), |
| ForeignItem(&'a ast::ForeignItem), |
| } |
| |
| /// Represents a fn's signature. |
| pub(crate) struct FnSig<'a> { |
| decl: &'a ast::FnDecl, |
| generics: &'a ast::Generics, |
| ext: ast::Extern, |
| coroutine_kind: Cow<'a, Option<ast::CoroutineKind>>, |
| constness: ast::Const, |
| defaultness: ast::Defaultness, |
| unsafety: ast::Unsafe, |
| visibility: &'a ast::Visibility, |
| } |
| |
| impl<'a> FnSig<'a> { |
| pub(crate) fn from_method_sig( |
| method_sig: &'a ast::FnSig, |
| generics: &'a ast::Generics, |
| visibility: &'a ast::Visibility, |
| ) -> FnSig<'a> { |
| FnSig { |
| unsafety: method_sig.header.unsafety, |
| coroutine_kind: Cow::Borrowed(&method_sig.header.coroutine_kind), |
| constness: method_sig.header.constness, |
| defaultness: ast::Defaultness::Final, |
| ext: method_sig.header.ext, |
| decl: &*method_sig.decl, |
| generics, |
| visibility, |
| } |
| } |
| |
| pub(crate) fn from_fn_kind( |
| fn_kind: &'a visit::FnKind<'_>, |
| decl: &'a ast::FnDecl, |
| defaultness: ast::Defaultness, |
| ) -> FnSig<'a> { |
| match *fn_kind { |
| visit::FnKind::Fn(visit::FnCtxt::Assoc(..), _, fn_sig, vis, generics, _) => { |
| let mut fn_sig = FnSig::from_method_sig(fn_sig, generics, vis); |
| fn_sig.defaultness = defaultness; |
| fn_sig |
| } |
| visit::FnKind::Fn(_, _, fn_sig, vis, generics, _) => FnSig { |
| decl, |
| generics, |
| ext: fn_sig.header.ext, |
| constness: fn_sig.header.constness, |
| coroutine_kind: Cow::Borrowed(&fn_sig.header.coroutine_kind), |
| defaultness, |
| unsafety: fn_sig.header.unsafety, |
| visibility: vis, |
| }, |
| _ => unreachable!(), |
| } |
| } |
| |
| fn to_str(&self, context: &RewriteContext<'_>) -> String { |
| let mut result = String::with_capacity(128); |
| // Vis defaultness constness unsafety abi. |
| result.push_str(&*format_visibility(context, self.visibility)); |
| result.push_str(format_defaultness(self.defaultness)); |
| result.push_str(format_constness(self.constness)); |
| self.coroutine_kind |
| .map(|coroutine_kind| result.push_str(format_coro(&coroutine_kind))); |
| result.push_str(format_unsafety(self.unsafety)); |
| result.push_str(&format_extern( |
| self.ext, |
| context.config.force_explicit_abi(), |
| )); |
| result |
| } |
| } |
| |
| impl<'a> FmtVisitor<'a> { |
| fn format_item(&mut self, item: &Item<'_>) { |
| self.buffer.push_str(format_unsafety(item.unsafety)); |
| self.buffer.push_str(&item.abi); |
| |
| let snippet = self.snippet(item.span); |
| let brace_pos = snippet.find_uncommented("{").unwrap(); |
| |
| self.push_str("{"); |
| if !item.body.is_empty() || contains_comment(&snippet[brace_pos..]) { |
| // FIXME: this skips comments between the extern keyword and the opening |
| // brace. |
| self.last_pos = item.span.lo() + BytePos(brace_pos as u32 + 1); |
| self.block_indent = self.block_indent.block_indent(self.config); |
| |
| if !item.body.is_empty() { |
| for item in &item.body { |
| self.format_body_element(item); |
| } |
| } |
| |
| self.format_missing_no_indent(item.span.hi() - BytePos(1)); |
| self.block_indent = self.block_indent.block_unindent(self.config); |
| let indent_str = self.block_indent.to_string(self.config); |
| self.push_str(&indent_str); |
| } |
| |
| self.push_str("}"); |
| self.last_pos = item.span.hi(); |
| } |
| |
| fn format_body_element(&mut self, element: &BodyElement<'_>) { |
| match *element { |
| BodyElement::ForeignItem(item) => self.format_foreign_item(item), |
| } |
| } |
| |
| pub(crate) fn format_foreign_mod(&mut self, fm: &ast::ForeignMod, span: Span) { |
| let item = Item::from_foreign_mod(fm, span, self.config); |
| self.format_item(&item); |
| } |
| |
| fn format_foreign_item(&mut self, item: &ast::ForeignItem) { |
| let rewrite = item.rewrite(&self.get_context(), self.shape()); |
| let hi = item.span.hi(); |
| let span = if item.attrs.is_empty() { |
| item.span |
| } else { |
| mk_sp(item.attrs[0].span.lo(), hi) |
| }; |
| self.push_rewrite(span, rewrite); |
| self.last_pos = hi; |
| } |
| |
| pub(crate) fn rewrite_fn_before_block( |
| &mut self, |
| indent: Indent, |
| ident: symbol::Ident, |
| fn_sig: &FnSig<'_>, |
| span: Span, |
| ) -> Option<(String, FnBraceStyle)> { |
| let context = self.get_context(); |
| |
| let mut fn_brace_style = newline_for_brace(self.config, &fn_sig.generics.where_clause); |
| let (result, _, force_newline_brace) = |
| rewrite_fn_base(&context, indent, ident, fn_sig, span, fn_brace_style)?; |
| |
| // 2 = ` {` |
| if self.config.brace_style() == BraceStyle::AlwaysNextLine |
| || force_newline_brace |
| || last_line_width(&result) + 2 > self.shape().width |
| { |
| fn_brace_style = FnBraceStyle::NextLine |
| } |
| |
| Some((result, fn_brace_style)) |
| } |
| |
| pub(crate) fn rewrite_required_fn( |
| &mut self, |
| indent: Indent, |
| ident: symbol::Ident, |
| sig: &ast::FnSig, |
| vis: &ast::Visibility, |
| generics: &ast::Generics, |
| span: Span, |
| ) -> Option<String> { |
| // Drop semicolon or it will be interpreted as comment. |
| let span = mk_sp(span.lo(), span.hi() - BytePos(1)); |
| let context = self.get_context(); |
| |
| let (mut result, ends_with_comment, _) = rewrite_fn_base( |
| &context, |
| indent, |
| ident, |
| &FnSig::from_method_sig(sig, generics, vis), |
| span, |
| FnBraceStyle::None, |
| )?; |
| |
| // If `result` ends with a comment, then remember to add a newline |
| if ends_with_comment { |
| result.push_str(&indent.to_string_with_newline(context.config)); |
| } |
| |
| // Re-attach semicolon |
| result.push(';'); |
| |
| Some(result) |
| } |
| |
| pub(crate) fn single_line_fn( |
| &self, |
| fn_str: &str, |
| block: &ast::Block, |
| inner_attrs: Option<&[ast::Attribute]>, |
| ) -> Option<String> { |
| if fn_str.contains('\n') || inner_attrs.map_or(false, |a| !a.is_empty()) { |
| return None; |
| } |
| |
| let context = self.get_context(); |
| |
| if self.config.empty_item_single_line() |
| && is_empty_block(&context, block, None) |
| && self.block_indent.width() + fn_str.len() + 3 <= self.config.max_width() |
| && !last_line_contains_single_line_comment(fn_str) |
| { |
| return Some(format!("{fn_str} {{}}")); |
| } |
| |
| if !self.config.fn_single_line() || !is_simple_block_stmt(&context, block, None) { |
| return None; |
| } |
| |
| let res = Stmt::from_ast_node(block.stmts.first()?, true) |
| .rewrite(&self.get_context(), self.shape())?; |
| |
| let width = self.block_indent.width() + fn_str.len() + res.len() + 5; |
| if !res.contains('\n') && width <= self.config.max_width() { |
| Some(format!("{fn_str} {{ {res} }}")) |
| } else { |
| None |
| } |
| } |
| |
| pub(crate) fn visit_static(&mut self, static_parts: &StaticParts<'_>) { |
| let rewrite = rewrite_static(&self.get_context(), static_parts, self.block_indent); |
| self.push_rewrite(static_parts.span, rewrite); |
| } |
| |
| pub(crate) fn visit_struct(&mut self, struct_parts: &StructParts<'_>) { |
| let is_tuple = match struct_parts.def { |
| ast::VariantData::Tuple(..) => true, |
| _ => false, |
| }; |
| let rewrite = format_struct(&self.get_context(), struct_parts, self.block_indent, None) |
| .map(|s| if is_tuple { s + ";" } else { s }); |
| self.push_rewrite(struct_parts.span, rewrite); |
| } |
| |
| pub(crate) fn visit_enum( |
| &mut self, |
| ident: symbol::Ident, |
| vis: &ast::Visibility, |
| enum_def: &ast::EnumDef, |
| generics: &ast::Generics, |
| span: Span, |
| ) { |
| let enum_header = |
| format_header(&self.get_context(), "enum ", ident, vis, self.block_indent); |
| self.push_str(&enum_header); |
| |
| let enum_snippet = self.snippet(span); |
| let brace_pos = enum_snippet.find_uncommented("{").unwrap(); |
| let body_start = span.lo() + BytePos(brace_pos as u32 + 1); |
| let generics_str = format_generics( |
| &self.get_context(), |
| generics, |
| self.config.brace_style(), |
| if enum_def.variants.is_empty() { |
| BracePos::ForceSameLine |
| } else { |
| BracePos::Auto |
| }, |
| self.block_indent, |
| // make a span that starts right after `enum Foo` |
| mk_sp(ident.span.hi(), body_start), |
| last_line_width(&enum_header), |
| ) |
| .unwrap(); |
| self.push_str(&generics_str); |
| |
| self.last_pos = body_start; |
| |
| match self.format_variant_list(enum_def, body_start, span.hi()) { |
| Some(ref s) if enum_def.variants.is_empty() => self.push_str(s), |
| rw => { |
| self.push_rewrite(mk_sp(body_start, span.hi()), rw); |
| self.block_indent = self.block_indent.block_unindent(self.config); |
| } |
| } |
| } |
| |
| // Format the body of an enum definition |
| fn format_variant_list( |
| &mut self, |
| enum_def: &ast::EnumDef, |
| body_lo: BytePos, |
| body_hi: BytePos, |
| ) -> Option<String> { |
| if enum_def.variants.is_empty() { |
| let mut buffer = String::with_capacity(128); |
| // 1 = "}" |
| let span = mk_sp(body_lo, body_hi - BytePos(1)); |
| format_empty_struct_or_tuple( |
| &self.get_context(), |
| span, |
| self.block_indent, |
| &mut buffer, |
| "", |
| "}", |
| ); |
| return Some(buffer); |
| } |
| let mut result = String::with_capacity(1024); |
| let original_offset = self.block_indent; |
| self.block_indent = self.block_indent.block_indent(self.config); |
| |
| // If enum variants have discriminants, try to vertically align those, |
| // provided the discrims are not shifted too much to the right |
| let align_threshold: usize = self.config.enum_discrim_align_threshold(); |
| let discr_ident_lens: Vec<usize> = enum_def |
| .variants |
| .iter() |
| .filter(|var| var.disr_expr.is_some()) |
| .map(|var| rewrite_ident(&self.get_context(), var.ident).len()) |
| .collect(); |
| // cut the list at the point of longest discrim shorter than the threshold |
| // All of the discrims under the threshold will get padded, and all above - left as is. |
| let pad_discrim_ident_to = *discr_ident_lens |
| .iter() |
| .filter(|&l| *l <= align_threshold) |
| .max() |
| .unwrap_or(&0); |
| |
| let itemize_list_with = |one_line_width: usize| { |
| itemize_list( |
| self.snippet_provider, |
| enum_def.variants.iter(), |
| "}", |
| ",", |
| |f| { |
| if !f.attrs.is_empty() { |
| f.attrs[0].span.lo() |
| } else { |
| f.span.lo() |
| } |
| }, |
| |f| f.span.hi(), |
| |f| self.format_variant(f, one_line_width, pad_discrim_ident_to), |
| body_lo, |
| body_hi, |
| false, |
| ) |
| .collect() |
| }; |
| let mut items: Vec<_> = itemize_list_with(self.config.struct_variant_width()); |
| |
| // If one of the variants use multiple lines, use multi-lined formatting for all variants. |
| let has_multiline_variant = items.iter().any(|item| item.inner_as_ref().contains('\n')); |
| let has_single_line_variant = items.iter().any(|item| !item.inner_as_ref().contains('\n')); |
| if has_multiline_variant && has_single_line_variant { |
| items = itemize_list_with(0); |
| } |
| |
| let shape = self.shape().sub_width(2)?; |
| let fmt = ListFormatting::new(shape, self.config) |
| .trailing_separator(self.config.trailing_comma()) |
| .preserve_newline(true); |
| |
| let list = write_list(&items, &fmt)?; |
| result.push_str(&list); |
| result.push_str(&original_offset.to_string_with_newline(self.config)); |
| result.push('}'); |
| Some(result) |
| } |
| |
| // Variant of an enum. |
| fn format_variant( |
| &self, |
| field: &ast::Variant, |
| one_line_width: usize, |
| pad_discrim_ident_to: usize, |
| ) -> Option<String> { |
| if contains_skip(&field.attrs) { |
| let lo = field.attrs[0].span.lo(); |
| let span = mk_sp(lo, field.span.hi()); |
| return Some(self.snippet(span).to_owned()); |
| } |
| |
| let context = self.get_context(); |
| // 1 = ',' |
| let shape = self.shape().sub_width(1)?; |
| let attrs_str = field.attrs.rewrite(&context, shape)?; |
| let lo = field |
| .attrs |
| .last() |
| .map_or(field.span.lo(), |attr| attr.span.hi()); |
| let span = mk_sp(lo, field.span.lo()); |
| |
| let variant_body = match field.data { |
| ast::VariantData::Tuple(..) | ast::VariantData::Struct { .. } => format_struct( |
| &context, |
| &StructParts::from_variant(field, &context), |
| self.block_indent, |
| Some(one_line_width), |
| )?, |
| ast::VariantData::Unit(..) => rewrite_ident(&context, field.ident).to_owned(), |
| }; |
| |
| let variant_body = if let Some(ref expr) = field.disr_expr { |
| let lhs = format!("{variant_body:pad_discrim_ident_to$} ="); |
| let ex = &*expr.value; |
| rewrite_assign_rhs_with( |
| &context, |
| lhs, |
| ex, |
| shape, |
| &RhsAssignKind::Expr(&ex.kind, ex.span), |
| RhsTactics::AllowOverflow, |
| )? |
| } else { |
| variant_body |
| }; |
| |
| combine_strs_with_missing_comments(&context, &attrs_str, &variant_body, span, shape, false) |
| } |
| |
| fn visit_impl_items(&mut self, items: &[ptr::P<ast::AssocItem>]) { |
| if self.get_context().config.reorder_impl_items() { |
| type TyOpt = Option<ptr::P<ast::Ty>>; |
| use crate::ast::AssocItemKind::*; |
| let is_type = |ty: &TyOpt| opaque_ty(ty).is_none(); |
| let is_opaque = |ty: &TyOpt| opaque_ty(ty).is_some(); |
| let both_type = |l: &TyOpt, r: &TyOpt| is_type(l) && is_type(r); |
| let both_opaque = |l: &TyOpt, r: &TyOpt| is_opaque(l) && is_opaque(r); |
| let need_empty_line = |a: &ast::AssocItemKind, b: &ast::AssocItemKind| match (a, b) { |
| (Type(lty), Type(rty)) |
| if both_type(<y.ty, &rty.ty) || both_opaque(<y.ty, &rty.ty) => |
| { |
| false |
| } |
| (Const(..), Const(..)) => false, |
| _ => true, |
| }; |
| |
| // Create visitor for each items, then reorder them. |
| let mut buffer = vec![]; |
| for item in items { |
| self.visit_impl_item(item); |
| buffer.push((self.buffer.clone(), item.clone())); |
| self.buffer.clear(); |
| } |
| |
| buffer.sort_by(|(_, a), (_, b)| match (&a.kind, &b.kind) { |
| (Type(lty), Type(rty)) |
| if both_type(<y.ty, &rty.ty) || both_opaque(<y.ty, &rty.ty) => |
| { |
| a.ident.as_str().cmp(b.ident.as_str()) |
| } |
| (Const(..), Const(..)) | (MacCall(..), MacCall(..)) => { |
| a.ident.as_str().cmp(b.ident.as_str()) |
| } |
| (Fn(..), Fn(..)) | (Delegation(..), Delegation(..)) => { |
| a.span.lo().cmp(&b.span.lo()) |
| } |
| (Type(ty), _) if is_type(&ty.ty) => Ordering::Less, |
| (_, Type(ty)) if is_type(&ty.ty) => Ordering::Greater, |
| (Type(..), _) => Ordering::Less, |
| (_, Type(..)) => Ordering::Greater, |
| (Const(..), _) => Ordering::Less, |
| (_, Const(..)) => Ordering::Greater, |
| (MacCall(..), _) => Ordering::Less, |
| (_, MacCall(..)) => Ordering::Greater, |
| (Delegation(..), _) => Ordering::Less, |
| (_, Delegation(..)) => Ordering::Greater, |
| }); |
| let mut prev_kind = None; |
| for (buf, item) in buffer { |
| // Make sure that there are at least a single empty line between |
| // different impl items. |
| if prev_kind |
| .as_ref() |
| .map_or(false, |prev_kind| need_empty_line(prev_kind, &item.kind)) |
| { |
| self.push_str("\n"); |
| } |
| let indent_str = self.block_indent.to_string_with_newline(self.config); |
| self.push_str(&indent_str); |
| self.push_str(buf.trim()); |
| prev_kind = Some(item.kind.clone()); |
| } |
| } else { |
| for item in items { |
| self.visit_impl_item(item); |
| } |
| } |
| } |
| } |
| |
| pub(crate) fn format_impl( |
| context: &RewriteContext<'_>, |
| item: &ast::Item, |
| iimpl: &ast::Impl, |
| offset: Indent, |
| ) -> Option<String> { |
| let ast::Impl { |
| generics, |
| self_ty, |
| items, |
| .. |
| } = iimpl; |
| let mut result = String::with_capacity(128); |
| let ref_and_type = format_impl_ref_and_type(context, item, iimpl, offset)?; |
| let sep = offset.to_string_with_newline(context.config); |
| result.push_str(&ref_and_type); |
| |
| let where_budget = if result.contains('\n') { |
| context.config.max_width() |
| } else { |
| context.budget(last_line_width(&result)) |
| }; |
| |
| let mut option = WhereClauseOption::snuggled(&ref_and_type); |
| let snippet = context.snippet(item.span); |
| let open_pos = snippet.find_uncommented("{")? + 1; |
| if !contains_comment(&snippet[open_pos..]) |
| && items.is_empty() |
| && generics.where_clause.predicates.len() == 1 |
| && !result.contains('\n') |
| { |
| option.suppress_comma(); |
| option.snuggle(); |
| option.allow_single_line(); |
| } |
| |
| let missing_span = mk_sp(self_ty.span.hi(), item.span.hi()); |
| let where_span_end = context.snippet_provider.opt_span_before(missing_span, "{"); |
| let where_clause_str = rewrite_where_clause( |
| context, |
| &generics.where_clause.predicates, |
| generics.where_clause.span, |
| context.config.brace_style(), |
| Shape::legacy(where_budget, offset.block_only()), |
| false, |
| "{", |
| where_span_end, |
| self_ty.span.hi(), |
| option, |
| )?; |
| |
| // If there is no where-clause, we may have missing comments between the trait name and |
| // the opening brace. |
| if generics.where_clause.predicates.is_empty() { |
| if let Some(hi) = where_span_end { |
| match recover_missing_comment_in_span( |
| mk_sp(self_ty.span.hi(), hi), |
| Shape::indented(offset, context.config), |
| context, |
| last_line_width(&result), |
| ) { |
| Some(ref missing_comment) if !missing_comment.is_empty() => { |
| result.push_str(missing_comment); |
| } |
| _ => (), |
| } |
| } |
| } |
| |
| if is_impl_single_line(context, items.as_slice(), &result, &where_clause_str, item)? { |
| result.push_str(&where_clause_str); |
| if where_clause_str.contains('\n') || last_line_contains_single_line_comment(&result) { |
| // if the where_clause contains extra comments AND |
| // there is only one where-clause predicate |
| // recover the suppressed comma in single line where_clause formatting |
| if generics.where_clause.predicates.len() == 1 { |
| result.push(','); |
| } |
| result.push_str(&format!("{sep}{{{sep}}}")); |
| } else { |
| result.push_str(" {}"); |
| } |
| return Some(result); |
| } |
| |
| result.push_str(&where_clause_str); |
| |
| let need_newline = last_line_contains_single_line_comment(&result) || result.contains('\n'); |
| match context.config.brace_style() { |
| _ if need_newline => result.push_str(&sep), |
| BraceStyle::AlwaysNextLine => result.push_str(&sep), |
| BraceStyle::PreferSameLine => result.push(' '), |
| BraceStyle::SameLineWhere => { |
| if !where_clause_str.is_empty() { |
| result.push_str(&sep); |
| } else { |
| result.push(' '); |
| } |
| } |
| } |
| |
| result.push('{'); |
| // this is an impl body snippet(impl SampleImpl { /* here */ }) |
| let lo = max(self_ty.span.hi(), generics.where_clause.span.hi()); |
| let snippet = context.snippet(mk_sp(lo, item.span.hi())); |
| let open_pos = snippet.find_uncommented("{")? + 1; |
| |
| if !items.is_empty() || contains_comment(&snippet[open_pos..]) { |
| let mut visitor = FmtVisitor::from_context(context); |
| let item_indent = offset.block_only().block_indent(context.config); |
| visitor.block_indent = item_indent; |
| visitor.last_pos = lo + BytePos(open_pos as u32); |
| |
| visitor.visit_attrs(&item.attrs, ast::AttrStyle::Inner); |
| visitor.visit_impl_items(items); |
| |
| visitor.format_missing(item.span.hi() - BytePos(1)); |
| |
| let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config); |
| let outer_indent_str = offset.block_only().to_string_with_newline(context.config); |
| |
| result.push_str(&inner_indent_str); |
| result.push_str(visitor.buffer.trim()); |
| result.push_str(&outer_indent_str); |
| } else if need_newline || !context.config.empty_item_single_line() { |
| result.push_str(&sep); |
| } |
| |
| result.push('}'); |
| |
| Some(result) |
| } |
| |
| fn is_impl_single_line( |
| context: &RewriteContext<'_>, |
| items: &[ptr::P<ast::AssocItem>], |
| result: &str, |
| where_clause_str: &str, |
| item: &ast::Item, |
| ) -> Option<bool> { |
| let snippet = context.snippet(item.span); |
| let open_pos = snippet.find_uncommented("{")? + 1; |
| |
| Some( |
| context.config.empty_item_single_line() |
| && items.is_empty() |
| && !result.contains('\n') |
| && result.len() + where_clause_str.len() <= context.config.max_width() |
| && !contains_comment(&snippet[open_pos..]), |
| ) |
| } |
| |
| fn format_impl_ref_and_type( |
| context: &RewriteContext<'_>, |
| item: &ast::Item, |
| iimpl: &ast::Impl, |
| offset: Indent, |
| ) -> Option<String> { |
| let ast::Impl { |
| unsafety, |
| polarity, |
| defaultness, |
| constness, |
| ref generics, |
| of_trait: ref trait_ref, |
| ref self_ty, |
| .. |
| } = *iimpl; |
| let mut result = String::with_capacity(128); |
| |
| result.push_str(&format_visibility(context, &item.vis)); |
| result.push_str(format_defaultness(defaultness)); |
| result.push_str(format_unsafety(unsafety)); |
| |
| let shape = if context.config.version() == Version::Two { |
| Shape::indented(offset + last_line_width(&result), context.config) |
| } else { |
| generics_shape_from_config( |
| context.config, |
| Shape::indented(offset + last_line_width(&result), context.config), |
| 0, |
| )? |
| }; |
| let generics_str = rewrite_generics(context, "impl", generics, shape)?; |
| result.push_str(&generics_str); |
| result.push_str(format_constness_right(constness)); |
| |
| let polarity_str = match polarity { |
| ast::ImplPolarity::Negative(_) => "!", |
| ast::ImplPolarity::Positive => "", |
| }; |
| |
| let polarity_overhead; |
| let trait_ref_overhead; |
| if let Some(ref trait_ref) = *trait_ref { |
| let result_len = last_line_width(&result); |
| result.push_str(&rewrite_trait_ref( |
| context, |
| trait_ref, |
| offset, |
| polarity_str, |
| result_len, |
| )?); |
| polarity_overhead = 0; // already written |
| trait_ref_overhead = " for".len(); |
| } else { |
| polarity_overhead = polarity_str.len(); |
| trait_ref_overhead = 0; |
| } |
| |
| // Try to put the self type in a single line. |
| let curly_brace_overhead = if generics.where_clause.predicates.is_empty() { |
| // If there is no where-clause adapt budget for type formatting to take space and curly |
| // brace into account. |
| match context.config.brace_style() { |
| BraceStyle::AlwaysNextLine => 0, |
| _ => 2, |
| } |
| } else { |
| 0 |
| }; |
| let used_space = |
| last_line_width(&result) + polarity_overhead + trait_ref_overhead + curly_brace_overhead; |
| // 1 = space before the type. |
| let budget = context.budget(used_space + 1); |
| if let Some(self_ty_str) = self_ty.rewrite(context, Shape::legacy(budget, offset)) { |
| if !self_ty_str.contains('\n') { |
| if trait_ref.is_some() { |
| result.push_str(" for "); |
| } else { |
| result.push(' '); |
| result.push_str(polarity_str); |
| } |
| result.push_str(&self_ty_str); |
| return Some(result); |
| } |
| } |
| |
| // Couldn't fit the self type on a single line, put it on a new line. |
| result.push('\n'); |
| // Add indentation of one additional tab. |
| let new_line_offset = offset.block_indent(context.config); |
| result.push_str(&new_line_offset.to_string(context.config)); |
| if trait_ref.is_some() { |
| result.push_str("for "); |
| } else { |
| result.push_str(polarity_str); |
| } |
| let budget = context.budget(last_line_width(&result) + polarity_overhead); |
| let type_offset = match context.config.indent_style() { |
| IndentStyle::Visual => new_line_offset + trait_ref_overhead, |
| IndentStyle::Block => new_line_offset, |
| }; |
| result.push_str(&*self_ty.rewrite(context, Shape::legacy(budget, type_offset))?); |
| Some(result) |
| } |
| |
| fn rewrite_trait_ref( |
| context: &RewriteContext<'_>, |
| trait_ref: &ast::TraitRef, |
| offset: Indent, |
| polarity_str: &str, |
| result_len: usize, |
| ) -> Option<String> { |
| // 1 = space between generics and trait_ref |
| let used_space = 1 + polarity_str.len() + result_len; |
| let shape = Shape::indented(offset + used_space, context.config); |
| if let Some(trait_ref_str) = trait_ref.rewrite(context, shape) { |
| if !trait_ref_str.contains('\n') { |
| return Some(format!(" {polarity_str}{trait_ref_str}")); |
| } |
| } |
| // We could not make enough space for trait_ref, so put it on new line. |
| let offset = offset.block_indent(context.config); |
| let shape = Shape::indented(offset, context.config); |
| let trait_ref_str = trait_ref.rewrite(context, shape)?; |
| Some(format!( |
| "{}{}{}", |
| offset.to_string_with_newline(context.config), |
| polarity_str, |
| trait_ref_str |
| )) |
| } |
| |
| pub(crate) struct StructParts<'a> { |
| prefix: &'a str, |
| ident: symbol::Ident, |
| vis: &'a ast::Visibility, |
| def: &'a ast::VariantData, |
| generics: Option<&'a ast::Generics>, |
| span: Span, |
| } |
| |
| impl<'a> StructParts<'a> { |
| fn format_header(&self, context: &RewriteContext<'_>, offset: Indent) -> String { |
| format_header(context, self.prefix, self.ident, self.vis, offset) |
| } |
| |
| fn from_variant(variant: &'a ast::Variant, context: &RewriteContext<'_>) -> Self { |
| StructParts { |
| prefix: "", |
| ident: variant.ident, |
| vis: &DEFAULT_VISIBILITY, |
| def: &variant.data, |
| generics: None, |
| span: enum_variant_span(variant, context), |
| } |
| } |
| |
| pub(crate) fn from_item(item: &'a ast::Item) -> Self { |
| let (prefix, def, generics) = match item.kind { |
| ast::ItemKind::Struct(ref def, ref generics) => ("struct ", def, generics), |
| ast::ItemKind::Union(ref def, ref generics) => ("union ", def, generics), |
| _ => unreachable!(), |
| }; |
| StructParts { |
| prefix, |
| ident: item.ident, |
| vis: &item.vis, |
| def, |
| generics: Some(generics), |
| span: item.span, |
| } |
| } |
| } |
| |
| fn enum_variant_span(variant: &ast::Variant, context: &RewriteContext<'_>) -> Span { |
| use ast::VariantData::*; |
| if let Some(ref anon_const) = variant.disr_expr { |
| let span_before_consts = variant.span.until(anon_const.value.span); |
| let hi = match &variant.data { |
| Struct { .. } => context |
| .snippet_provider |
| .span_after_last(span_before_consts, "}"), |
| Tuple(..) => context |
| .snippet_provider |
| .span_after_last(span_before_consts, ")"), |
| Unit(..) => variant.ident.span.hi(), |
| }; |
| mk_sp(span_before_consts.lo(), hi) |
| } else { |
| variant.span |
| } |
| } |
| |
| fn format_struct( |
| context: &RewriteContext<'_>, |
| struct_parts: &StructParts<'_>, |
| offset: Indent, |
| one_line_width: Option<usize>, |
| ) -> Option<String> { |
| match struct_parts.def { |
| ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset), |
| ast::VariantData::Tuple(fields, _) => { |
| format_tuple_struct(context, struct_parts, fields, offset) |
| } |
| ast::VariantData::Struct { fields, .. } => { |
| format_struct_struct(context, struct_parts, fields, offset, one_line_width) |
| } |
| } |
| } |
| |
| pub(crate) fn format_trait( |
| context: &RewriteContext<'_>, |
| item: &ast::Item, |
| offset: Indent, |
| ) -> Option<String> { |
| let ast::ItemKind::Trait(trait_kind) = &item.kind else { |
| unreachable!(); |
| }; |
| let ast::Trait { |
| is_auto, |
| unsafety, |
| ref generics, |
| ref bounds, |
| ref items, |
| } = **trait_kind; |
| |
| let mut result = String::with_capacity(128); |
| let header = format!( |
| "{}{}{}trait ", |
| format_visibility(context, &item.vis), |
| format_unsafety(unsafety), |
| format_auto(is_auto), |
| ); |
| result.push_str(&header); |
| |
| let body_lo = context.snippet_provider.span_after(item.span, "{"); |
| |
| let shape = Shape::indented(offset, context.config).offset_left(result.len())?; |
| let generics_str = |
| rewrite_generics(context, rewrite_ident(context, item.ident), generics, shape)?; |
| result.push_str(&generics_str); |
| |
| // FIXME(#2055): rustfmt fails to format when there are comments between trait bounds. |
| if !bounds.is_empty() { |
| let ident_hi = context |
| .snippet_provider |
| .span_after(item.span, item.ident.as_str()); |
| let bound_hi = bounds.last().unwrap().span().hi(); |
| let snippet = context.snippet(mk_sp(ident_hi, bound_hi)); |
| if contains_comment(snippet) { |
| return None; |
| } |
| |
| result = rewrite_assign_rhs_with( |
| context, |
| result + ":", |
| bounds, |
| shape, |
| &RhsAssignKind::Bounds, |
| RhsTactics::ForceNextLineWithoutIndent, |
| )?; |
| } |
| |
| // Rewrite where-clause. |
| if !generics.where_clause.predicates.is_empty() { |
| let where_on_new_line = context.config.indent_style() != IndentStyle::Block; |
| |
| let where_budget = context.budget(last_line_width(&result)); |
| let pos_before_where = if bounds.is_empty() { |
| generics.where_clause.span.lo() |
| } else { |
| bounds[bounds.len() - 1].span().hi() |
| }; |
| let option = WhereClauseOption::snuggled(&generics_str); |
| let where_clause_str = rewrite_where_clause( |
| context, |
| &generics.where_clause.predicates, |
| generics.where_clause.span, |
| context.config.brace_style(), |
| Shape::legacy(where_budget, offset.block_only()), |
| where_on_new_line, |
| "{", |
| None, |
| pos_before_where, |
| option, |
| )?; |
| // If the where-clause cannot fit on the same line, |
| // put the where-clause on a new line |
| if !where_clause_str.contains('\n') |
| && last_line_width(&result) + where_clause_str.len() + offset.width() |
| > context.config.comment_width() |
| { |
| let width = offset.block_indent + context.config.tab_spaces() - 1; |
| let where_indent = Indent::new(0, width); |
| result.push_str(&where_indent.to_string_with_newline(context.config)); |
| } |
| result.push_str(&where_clause_str); |
| } else { |
| let item_snippet = context.snippet(item.span); |
| if let Some(lo) = item_snippet.find('/') { |
| // 1 = `{` |
| let comment_hi = if generics.params.len() > 0 { |
| generics.span.lo() - BytePos(1) |
| } else { |
| body_lo - BytePos(1) |
| }; |
| let comment_lo = item.span.lo() + BytePos(lo as u32); |
| if comment_lo < comment_hi { |
| match recover_missing_comment_in_span( |
| mk_sp(comment_lo, comment_hi), |
| Shape::indented(offset, context.config), |
| context, |
| last_line_width(&result), |
| ) { |
| Some(ref missing_comment) if !missing_comment.is_empty() => { |
| result.push_str(missing_comment); |
| } |
| _ => (), |
| } |
| } |
| } |
| } |
| |
| let block_span = mk_sp(generics.where_clause.span.hi(), item.span.hi()); |
| let snippet = context.snippet(block_span); |
| let open_pos = snippet.find_uncommented("{")? + 1; |
| |
| match context.config.brace_style() { |
| _ if last_line_contains_single_line_comment(&result) |
| || last_line_width(&result) + 2 > context.budget(offset.width()) => |
| { |
| result.push_str(&offset.to_string_with_newline(context.config)); |
| } |
| _ if context.config.empty_item_single_line() |
| && items.is_empty() |
| && !result.contains('\n') |
| && !contains_comment(&snippet[open_pos..]) => |
| { |
| result.push_str(" {}"); |
| return Some(result); |
| } |
| BraceStyle::AlwaysNextLine => { |
| result.push_str(&offset.to_string_with_newline(context.config)); |
| } |
| BraceStyle::PreferSameLine => result.push(' '), |
| BraceStyle::SameLineWhere => { |
| if result.contains('\n') |
| || (!generics.where_clause.predicates.is_empty() && !items.is_empty()) |
| { |
| result.push_str(&offset.to_string_with_newline(context.config)); |
| } else { |
| result.push(' '); |
| } |
| } |
| } |
| result.push('{'); |
| |
| let outer_indent_str = offset.block_only().to_string_with_newline(context.config); |
| |
| if !items.is_empty() || contains_comment(&snippet[open_pos..]) { |
| let mut visitor = FmtVisitor::from_context(context); |
| visitor.block_indent = offset.block_only().block_indent(context.config); |
| visitor.last_pos = block_span.lo() + BytePos(open_pos as u32); |
| |
| for item in items { |
| visitor.visit_trait_item(item); |
| } |
| |
| visitor.format_missing(item.span.hi() - BytePos(1)); |
| |
| let inner_indent_str = visitor.block_indent.to_string_with_newline(context.config); |
| |
| result.push_str(&inner_indent_str); |
| result.push_str(visitor.buffer.trim()); |
| result.push_str(&outer_indent_str); |
| } else if result.contains('\n') { |
| result.push_str(&outer_indent_str); |
| } |
| |
| result.push('}'); |
| Some(result) |
| } |
| |
| pub(crate) struct TraitAliasBounds<'a> { |
| generic_bounds: &'a ast::GenericBounds, |
| generics: &'a ast::Generics, |
| } |
| |
| impl<'a> Rewrite for TraitAliasBounds<'a> { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| let generic_bounds_str = self.generic_bounds.rewrite(context, shape)?; |
| |
| let mut option = WhereClauseOption::new(true, WhereClauseSpace::None); |
| option.allow_single_line(); |
| |
| let where_str = rewrite_where_clause( |
| context, |
| &self.generics.where_clause.predicates, |
| self.generics.where_clause.span, |
| context.config.brace_style(), |
| shape, |
| false, |
| ";", |
| None, |
| self.generics.where_clause.span.lo(), |
| option, |
| )?; |
| |
| let fits_single_line = !generic_bounds_str.contains('\n') |
| && !where_str.contains('\n') |
| && generic_bounds_str.len() + where_str.len() < shape.width; |
| let space = if generic_bounds_str.is_empty() || where_str.is_empty() { |
| Cow::from("") |
| } else if fits_single_line { |
| Cow::from(" ") |
| } else { |
| shape.indent.to_string_with_newline(context.config) |
| }; |
| |
| Some(format!("{generic_bounds_str}{space}{where_str}")) |
| } |
| } |
| |
| pub(crate) fn format_trait_alias( |
| context: &RewriteContext<'_>, |
| ident: symbol::Ident, |
| vis: &ast::Visibility, |
| generics: &ast::Generics, |
| generic_bounds: &ast::GenericBounds, |
| shape: Shape, |
| ) -> Option<String> { |
| let alias = rewrite_ident(context, ident); |
| // 6 = "trait ", 2 = " =" |
| let g_shape = shape.offset_left(6)?.sub_width(2)?; |
| let generics_str = rewrite_generics(context, alias, generics, g_shape)?; |
| let vis_str = format_visibility(context, vis); |
| let lhs = format!("{vis_str}trait {generics_str} ="); |
| // 1 = ";" |
| let trait_alias_bounds = TraitAliasBounds { |
| generic_bounds, |
| generics, |
| }; |
| rewrite_assign_rhs( |
| context, |
| lhs, |
| &trait_alias_bounds, |
| &RhsAssignKind::Bounds, |
| shape.sub_width(1)?, |
| ) |
| .map(|s| s + ";") |
| } |
| |
| fn format_unit_struct( |
| context: &RewriteContext<'_>, |
| p: &StructParts<'_>, |
| offset: Indent, |
| ) -> Option<String> { |
| let header_str = format_header(context, p.prefix, p.ident, p.vis, offset); |
| let generics_str = if let Some(generics) = p.generics { |
| let hi = context.snippet_provider.span_before_last(p.span, ";"); |
| format_generics( |
| context, |
| generics, |
| context.config.brace_style(), |
| BracePos::None, |
| offset, |
| // make a span that starts right after `struct Foo` |
| mk_sp(p.ident.span.hi(), hi), |
| last_line_width(&header_str), |
| )? |
| } else { |
| String::new() |
| }; |
| Some(format!("{header_str}{generics_str};")) |
| } |
| |
| pub(crate) fn format_struct_struct( |
| context: &RewriteContext<'_>, |
| struct_parts: &StructParts<'_>, |
| fields: &[ast::FieldDef], |
| offset: Indent, |
| one_line_width: Option<usize>, |
| ) -> Option<String> { |
| let mut result = String::with_capacity(1024); |
| let span = struct_parts.span; |
| |
| let header_str = struct_parts.format_header(context, offset); |
| result.push_str(&header_str); |
| |
| let header_hi = struct_parts.ident.span.hi(); |
| let body_lo = if let Some(generics) = struct_parts.generics { |
| // Adjust the span to start at the end of the generic arguments before searching for the '{' |
| let span = span.with_lo(generics.where_clause.span.hi()); |
| context.snippet_provider.span_after(span, "{") |
| } else { |
| context.snippet_provider.span_after(span, "{") |
| }; |
| |
| let generics_str = match struct_parts.generics { |
| Some(g) => format_generics( |
| context, |
| g, |
| context.config.brace_style(), |
| if fields.is_empty() { |
| BracePos::ForceSameLine |
| } else { |
| BracePos::Auto |
| }, |
| offset, |
| // make a span that starts right after `struct Foo` |
| mk_sp(header_hi, body_lo), |
| last_line_width(&result), |
| )?, |
| None => { |
| // 3 = ` {}`, 2 = ` {`. |
| let overhead = if fields.is_empty() { 3 } else { 2 }; |
| if (context.config.brace_style() == BraceStyle::AlwaysNextLine && !fields.is_empty()) |
| || context.config.max_width() < overhead + result.len() |
| { |
| format!("\n{}{{", offset.block_only().to_string(context.config)) |
| } else { |
| " {".to_owned() |
| } |
| } |
| }; |
| // 1 = `}` |
| let overhead = if fields.is_empty() { 1 } else { 0 }; |
| let total_width = result.len() + generics_str.len() + overhead; |
| if !generics_str.is_empty() |
| && !generics_str.contains('\n') |
| && total_width > context.config.max_width() |
| { |
| result.push('\n'); |
| result.push_str(&offset.to_string(context.config)); |
| result.push_str(generics_str.trim_start()); |
| } else { |
| result.push_str(&generics_str); |
| } |
| |
| if fields.is_empty() { |
| let inner_span = mk_sp(body_lo, span.hi() - BytePos(1)); |
| format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "", "}"); |
| return Some(result); |
| } |
| |
| // 3 = ` ` and ` }` |
| let one_line_budget = context.budget(result.len() + 3 + offset.width()); |
| let one_line_budget = |
| one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget)); |
| |
| let items_str = rewrite_with_alignment( |
| fields, |
| context, |
| Shape::indented(offset.block_indent(context.config), context.config).sub_width(1)?, |
| mk_sp(body_lo, span.hi()), |
| one_line_budget, |
| )?; |
| |
| if !items_str.contains('\n') |
| && !result.contains('\n') |
| && items_str.len() <= one_line_budget |
| && !last_line_contains_single_line_comment(&items_str) |
| { |
| Some(format!("{result} {items_str} }}")) |
| } else { |
| Some(format!( |
| "{}\n{}{}\n{}}}", |
| result, |
| offset |
| .block_indent(context.config) |
| .to_string(context.config), |
| items_str, |
| offset.to_string(context.config) |
| )) |
| } |
| } |
| |
| fn get_bytepos_after_visibility(vis: &ast::Visibility, default_span: Span) -> BytePos { |
| match vis.kind { |
| ast::VisibilityKind::Restricted { .. } => vis.span.hi(), |
| _ => default_span.lo(), |
| } |
| } |
| |
| // Format tuple or struct without any fields. We need to make sure that the comments |
| // inside the delimiters are preserved. |
| fn format_empty_struct_or_tuple( |
| context: &RewriteContext<'_>, |
| span: Span, |
| offset: Indent, |
| result: &mut String, |
| opener: &str, |
| closer: &str, |
| ) { |
| // 3 = " {}" or "();" |
| let used_width = last_line_used_width(result, offset.width()) + 3; |
| if used_width > context.config.max_width() { |
| result.push_str(&offset.to_string_with_newline(context.config)) |
| } |
| result.push_str(opener); |
| |
| // indented shape for proper indenting of multi-line comments |
| let shape = Shape::indented(offset.block_indent(context.config), context.config); |
| match rewrite_missing_comment(span, shape, context) { |
| Some(ref s) if s.is_empty() => (), |
| Some(ref s) => { |
| let is_multi_line = !is_single_line(s); |
| if is_multi_line || first_line_contains_single_line_comment(s) { |
| let nested_indent_str = offset |
| .block_indent(context.config) |
| .to_string_with_newline(context.config); |
| result.push_str(&nested_indent_str); |
| } |
| result.push_str(s); |
| if is_multi_line || last_line_contains_single_line_comment(s) { |
| result.push_str(&offset.to_string_with_newline(context.config)); |
| } |
| } |
| None => result.push_str(context.snippet(span)), |
| } |
| result.push_str(closer); |
| } |
| |
| fn format_tuple_struct( |
| context: &RewriteContext<'_>, |
| struct_parts: &StructParts<'_>, |
| fields: &[ast::FieldDef], |
| offset: Indent, |
| ) -> Option<String> { |
| let mut result = String::with_capacity(1024); |
| let span = struct_parts.span; |
| |
| let header_str = struct_parts.format_header(context, offset); |
| result.push_str(&header_str); |
| |
| let body_lo = if fields.is_empty() { |
| let lo = get_bytepos_after_visibility(struct_parts.vis, span); |
| context |
| .snippet_provider |
| .span_after(mk_sp(lo, span.hi()), "(") |
| } else { |
| fields[0].span.lo() |
| }; |
| let body_hi = if fields.is_empty() { |
| context |
| .snippet_provider |
| .span_after(mk_sp(body_lo, span.hi()), ")") |
| } else { |
| // This is a dirty hack to work around a missing `)` from the span of the last field. |
| let last_arg_span = fields[fields.len() - 1].span; |
| context |
| .snippet_provider |
| .opt_span_after(mk_sp(last_arg_span.hi(), span.hi()), ")") |
| .unwrap_or_else(|| last_arg_span.hi()) |
| }; |
| |
| let where_clause_str = match struct_parts.generics { |
| Some(generics) => { |
| let budget = context.budget(last_line_width(&header_str)); |
| let shape = Shape::legacy(budget, offset); |
| let generics_str = rewrite_generics(context, "", generics, shape)?; |
| result.push_str(&generics_str); |
| |
| let where_budget = context.budget(last_line_width(&result)); |
| let option = WhereClauseOption::new(true, WhereClauseSpace::Newline); |
| rewrite_where_clause( |
| context, |
| &generics.where_clause.predicates, |
| generics.where_clause.span, |
| context.config.brace_style(), |
| Shape::legacy(where_budget, offset.block_only()), |
| false, |
| ";", |
| None, |
| body_hi, |
| option, |
| )? |
| } |
| None => "".to_owned(), |
| }; |
| |
| if fields.is_empty() { |
| let body_hi = context |
| .snippet_provider |
| .span_before(mk_sp(body_lo, span.hi()), ")"); |
| let inner_span = mk_sp(body_lo, body_hi); |
| format_empty_struct_or_tuple(context, inner_span, offset, &mut result, "(", ")"); |
| } else { |
| let shape = Shape::indented(offset, context.config).sub_width(1)?; |
| let lo = if let Some(generics) = struct_parts.generics { |
| generics.span.hi() |
| } else { |
| struct_parts.ident.span.hi() |
| }; |
| result = overflow::rewrite_with_parens( |
| context, |
| &result, |
| fields.iter(), |
| shape, |
| mk_sp(lo, span.hi()), |
| context.config.fn_call_width(), |
| None, |
| )?; |
| } |
| |
| if !where_clause_str.is_empty() |
| && !where_clause_str.contains('\n') |
| && (result.contains('\n') |
| || offset.block_indent + result.len() + where_clause_str.len() + 1 |
| > context.config.max_width()) |
| { |
| // We need to put the where-clause on a new line, but we didn't |
| // know that earlier, so the where-clause will not be indented properly. |
| result.push('\n'); |
| result.push_str( |
| &(offset.block_only() + (context.config.tab_spaces() - 1)).to_string(context.config), |
| ); |
| } |
| result.push_str(&where_clause_str); |
| |
| Some(result) |
| } |
| |
| pub(crate) enum ItemVisitorKind<'a> { |
| Item(&'a ast::Item), |
| AssocTraitItem(&'a ast::AssocItem), |
| AssocImplItem(&'a ast::AssocItem), |
| ForeignItem(&'a ast::ForeignItem), |
| } |
| |
| struct TyAliasRewriteInfo<'c, 'g>( |
| &'c RewriteContext<'c>, |
| Indent, |
| &'g ast::Generics, |
| ast::TyAliasWhereClauses, |
| symbol::Ident, |
| Span, |
| ); |
| |
| pub(crate) fn rewrite_type_alias<'a, 'b>( |
| ty_alias_kind: &ast::TyAlias, |
| context: &RewriteContext<'a>, |
| indent: Indent, |
| visitor_kind: &ItemVisitorKind<'b>, |
| span: Span, |
| ) -> Option<String> { |
| use ItemVisitorKind::*; |
| |
| let ast::TyAlias { |
| defaultness, |
| ref generics, |
| ref bounds, |
| ref ty, |
| where_clauses, |
| } = *ty_alias_kind; |
| let ty_opt = ty.as_ref(); |
| let (ident, vis) = match visitor_kind { |
| Item(i) => (i.ident, &i.vis), |
| AssocTraitItem(i) | AssocImplItem(i) => (i.ident, &i.vis), |
| ForeignItem(i) => (i.ident, &i.vis), |
| }; |
| let rw_info = &TyAliasRewriteInfo(context, indent, generics, where_clauses, ident, span); |
| let op_ty = opaque_ty(ty); |
| // Type Aliases are formatted slightly differently depending on the context |
| // in which they appear, whether they are opaque, and whether they are associated. |
| // https://rustc-dev-guide.rust-lang.org/opaque-types-type-alias-impl-trait.html |
| // https://github.com/rust-dev-tools/fmt-rfcs/blob/master/guide/items.md#type-aliases |
| match (visitor_kind, &op_ty) { |
| (Item(_) | AssocTraitItem(_) | ForeignItem(_), Some(op_bounds)) => { |
| let op = OpaqueType { bounds: op_bounds }; |
| rewrite_ty(rw_info, Some(bounds), Some(&op), vis) |
| } |
| (Item(_) | AssocTraitItem(_) | ForeignItem(_), None) => { |
| rewrite_ty(rw_info, Some(bounds), ty_opt, vis) |
| } |
| (AssocImplItem(_), _) => { |
| let result = if let Some(op_bounds) = op_ty { |
| let op = OpaqueType { bounds: op_bounds }; |
| rewrite_ty(rw_info, Some(bounds), Some(&op), &DEFAULT_VISIBILITY) |
| } else { |
| rewrite_ty(rw_info, Some(bounds), ty_opt, vis) |
| }?; |
| match defaultness { |
| ast::Defaultness::Default(..) => Some(format!("default {result}")), |
| _ => Some(result), |
| } |
| } |
| } |
| } |
| |
| fn rewrite_ty<R: Rewrite>( |
| rw_info: &TyAliasRewriteInfo<'_, '_>, |
| generic_bounds_opt: Option<&ast::GenericBounds>, |
| rhs: Option<&R>, |
| vis: &ast::Visibility, |
| ) -> Option<String> { |
| let mut result = String::with_capacity(128); |
| let TyAliasRewriteInfo(context, indent, generics, where_clauses, ident, span) = *rw_info; |
| let (before_where_predicates, after_where_predicates) = generics |
| .where_clause |
| .predicates |
| .split_at(where_clauses.split); |
| if !after_where_predicates.is_empty() { |
| return None; |
| } |
| result.push_str(&format!("{}type ", format_visibility(context, vis))); |
| let ident_str = rewrite_ident(context, ident); |
| |
| if generics.params.is_empty() { |
| result.push_str(ident_str) |
| } else { |
| // 2 = `= ` |
| let g_shape = Shape::indented(indent, context.config) |
| .offset_left(result.len())? |
| .sub_width(2)?; |
| let generics_str = rewrite_generics(context, ident_str, generics, g_shape)?; |
| result.push_str(&generics_str); |
| } |
| |
| if let Some(bounds) = generic_bounds_opt { |
| if !bounds.is_empty() { |
| // 2 = `: ` |
| let shape = Shape::indented(indent, context.config).offset_left(result.len() + 2)?; |
| let type_bounds = bounds.rewrite(context, shape).map(|s| format!(": {}", s))?; |
| result.push_str(&type_bounds); |
| } |
| } |
| |
| let where_budget = context.budget(last_line_width(&result)); |
| let mut option = WhereClauseOption::snuggled(&result); |
| if rhs.is_none() { |
| option.suppress_comma(); |
| } |
| let where_clause_str = rewrite_where_clause( |
| context, |
| before_where_predicates, |
| where_clauses.before.span, |
| context.config.brace_style(), |
| Shape::legacy(where_budget, indent), |
| false, |
| "=", |
| None, |
| generics.span.hi(), |
| option, |
| )?; |
| result.push_str(&where_clause_str); |
| |
| if let Some(ty) = rhs { |
| // If there's a where clause, add a newline before the assignment. Otherwise just add a |
| // space. |
| let has_where = !before_where_predicates.is_empty(); |
| if has_where { |
| result.push_str(&indent.to_string_with_newline(context.config)); |
| } else { |
| result.push(' '); |
| } |
| |
| let comment_span = context |
| .snippet_provider |
| .opt_span_before(span, "=") |
| .map(|op_lo| mk_sp(where_clauses.before.span.hi(), op_lo)); |
| |
| let lhs = match comment_span { |
| Some(comment_span) |
| if contains_comment(context.snippet_provider.span_to_snippet(comment_span)?) => |
| { |
| let comment_shape = if has_where { |
| Shape::indented(indent, context.config) |
| } else { |
| Shape::indented(indent, context.config) |
| .block_left(context.config.tab_spaces())? |
| }; |
| |
| combine_strs_with_missing_comments( |
| context, |
| result.trim_end(), |
| "=", |
| comment_span, |
| comment_shape, |
| true, |
| )? |
| } |
| _ => format!("{result}="), |
| }; |
| |
| // 1 = `;` |
| let shape = Shape::indented(indent, context.config).sub_width(1)?; |
| rewrite_assign_rhs(context, lhs, &*ty, &RhsAssignKind::Ty, shape).map(|s| s + ";") |
| } else { |
| Some(format!("{result};")) |
| } |
| } |
| |
| fn type_annotation_spacing(config: &Config) -> (&str, &str) { |
| ( |
| if config.space_before_colon() { " " } else { "" }, |
| if config.space_after_colon() { " " } else { "" }, |
| ) |
| } |
| |
| pub(crate) fn rewrite_struct_field_prefix( |
| context: &RewriteContext<'_>, |
| field: &ast::FieldDef, |
| ) -> Option<String> { |
| let vis = format_visibility(context, &field.vis); |
| let type_annotation_spacing = type_annotation_spacing(context.config); |
| Some(match field.ident { |
| Some(name) => format!( |
| "{}{}{}:", |
| vis, |
| rewrite_ident(context, name), |
| type_annotation_spacing.0 |
| ), |
| None => vis.to_string(), |
| }) |
| } |
| |
| impl Rewrite for ast::FieldDef { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| rewrite_struct_field(context, self, shape, 0) |
| } |
| } |
| |
| pub(crate) fn rewrite_struct_field( |
| context: &RewriteContext<'_>, |
| field: &ast::FieldDef, |
| shape: Shape, |
| lhs_max_width: usize, |
| ) -> Option<String> { |
| if contains_skip(&field.attrs) { |
| return Some(context.snippet(field.span()).to_owned()); |
| } |
| |
| let type_annotation_spacing = type_annotation_spacing(context.config); |
| let prefix = rewrite_struct_field_prefix(context, field)?; |
| |
| let attrs_str = field.attrs.rewrite(context, shape)?; |
| let attrs_extendable = field.ident.is_none() && is_attributes_extendable(&attrs_str); |
| let missing_span = if field.attrs.is_empty() { |
| mk_sp(field.span.lo(), field.span.lo()) |
| } else { |
| mk_sp(field.attrs.last().unwrap().span.hi(), field.span.lo()) |
| }; |
| let mut spacing = String::from(if field.ident.is_some() { |
| type_annotation_spacing.1 |
| } else { |
| "" |
| }); |
| // Try to put everything on a single line. |
| let attr_prefix = combine_strs_with_missing_comments( |
| context, |
| &attrs_str, |
| &prefix, |
| missing_span, |
| shape, |
| attrs_extendable, |
| )?; |
| let overhead = trimmed_last_line_width(&attr_prefix); |
| let lhs_offset = lhs_max_width.saturating_sub(overhead); |
| for _ in 0..lhs_offset { |
| spacing.push(' '); |
| } |
| // In this extreme case we will be missing a space between an attribute and a field. |
| if prefix.is_empty() && !attrs_str.is_empty() && attrs_extendable && spacing.is_empty() { |
| spacing.push(' '); |
| } |
| let orig_ty = shape |
| .offset_left(overhead + spacing.len()) |
| .and_then(|ty_shape| field.ty.rewrite(context, ty_shape)); |
| if let Some(ref ty) = orig_ty { |
| if !ty.contains('\n') && !contains_comment(context.snippet(missing_span)) { |
| return Some(attr_prefix + &spacing + ty); |
| } |
| } |
| |
| let is_prefix_empty = prefix.is_empty(); |
| // We must use multiline. We are going to put attributes and a field on different lines. |
| let field_str = rewrite_assign_rhs(context, prefix, &*field.ty, &RhsAssignKind::Ty, shape)?; |
| // Remove a leading white-space from `rewrite_assign_rhs()` when rewriting a tuple struct. |
| let field_str = if is_prefix_empty { |
| field_str.trim_start() |
| } else { |
| &field_str |
| }; |
| combine_strs_with_missing_comments(context, &attrs_str, field_str, missing_span, shape, false) |
| } |
| |
| pub(crate) struct StaticParts<'a> { |
| prefix: &'a str, |
| vis: &'a ast::Visibility, |
| ident: symbol::Ident, |
| ty: &'a ast::Ty, |
| mutability: ast::Mutability, |
| expr_opt: Option<&'a ptr::P<ast::Expr>>, |
| defaultness: Option<ast::Defaultness>, |
| span: Span, |
| } |
| |
| impl<'a> StaticParts<'a> { |
| pub(crate) fn from_item(item: &'a ast::Item) -> Self { |
| let (defaultness, prefix, ty, mutability, expr) = match &item.kind { |
| ast::ItemKind::Static(s) => (None, "static", &s.ty, s.mutability, &s.expr), |
| ast::ItemKind::Const(c) => ( |
| Some(c.defaultness), |
| "const", |
| &c.ty, |
| ast::Mutability::Not, |
| &c.expr, |
| ), |
| _ => unreachable!(), |
| }; |
| StaticParts { |
| prefix, |
| vis: &item.vis, |
| ident: item.ident, |
| ty, |
| mutability, |
| expr_opt: expr.as_ref(), |
| defaultness, |
| span: item.span, |
| } |
| } |
| |
| pub(crate) fn from_trait_item(ti: &'a ast::AssocItem) -> Self { |
| let (defaultness, ty, expr_opt) = match &ti.kind { |
| ast::AssocItemKind::Const(c) => (c.defaultness, &c.ty, &c.expr), |
| _ => unreachable!(), |
| }; |
| StaticParts { |
| prefix: "const", |
| vis: &ti.vis, |
| ident: ti.ident, |
| ty, |
| mutability: ast::Mutability::Not, |
| expr_opt: expr_opt.as_ref(), |
| defaultness: Some(defaultness), |
| span: ti.span, |
| } |
| } |
| |
| pub(crate) fn from_impl_item(ii: &'a ast::AssocItem) -> Self { |
| let (defaultness, ty, expr) = match &ii.kind { |
| ast::AssocItemKind::Const(c) => (c.defaultness, &c.ty, &c.expr), |
| _ => unreachable!(), |
| }; |
| StaticParts { |
| prefix: "const", |
| vis: &ii.vis, |
| ident: ii.ident, |
| ty, |
| mutability: ast::Mutability::Not, |
| expr_opt: expr.as_ref(), |
| defaultness: Some(defaultness), |
| span: ii.span, |
| } |
| } |
| } |
| |
| fn rewrite_static( |
| context: &RewriteContext<'_>, |
| static_parts: &StaticParts<'_>, |
| offset: Indent, |
| ) -> Option<String> { |
| let colon = colon_spaces(context.config); |
| let mut prefix = format!( |
| "{}{}{} {}{}{}", |
| format_visibility(context, static_parts.vis), |
| static_parts.defaultness.map_or("", format_defaultness), |
| static_parts.prefix, |
| format_mutability(static_parts.mutability), |
| rewrite_ident(context, static_parts.ident), |
| colon, |
| ); |
| // 2 = " =".len() |
| let ty_shape = |
| Shape::indented(offset.block_only(), context.config).offset_left(prefix.len() + 2)?; |
| let ty_str = match static_parts.ty.rewrite(context, ty_shape) { |
| Some(ty_str) => ty_str, |
| None => { |
| if prefix.ends_with(' ') { |
| prefix.pop(); |
| } |
| let nested_indent = offset.block_indent(context.config); |
| let nested_shape = Shape::indented(nested_indent, context.config); |
| let ty_str = static_parts.ty.rewrite(context, nested_shape)?; |
| format!( |
| "{}{}", |
| nested_indent.to_string_with_newline(context.config), |
| ty_str |
| ) |
| } |
| }; |
| |
| if let Some(expr) = static_parts.expr_opt { |
| let comments_lo = context.snippet_provider.span_after(static_parts.span, "="); |
| let expr_lo = expr.span.lo(); |
| let comments_span = mk_sp(comments_lo, expr_lo); |
| |
| let lhs = format!("{prefix}{ty_str} ="); |
| |
| // 1 = ; |
| let remaining_width = context.budget(offset.block_indent + 1); |
| rewrite_assign_rhs_with_comments( |
| context, |
| &lhs, |
| &**expr, |
| Shape::legacy(remaining_width, offset.block_only()), |
| &RhsAssignKind::Expr(&expr.kind, expr.span), |
| RhsTactics::Default, |
| comments_span, |
| true, |
| ) |
| .and_then(|res| recover_comment_removed(res, static_parts.span, context)) |
| .map(|s| if s.ends_with(';') { s } else { s + ";" }) |
| } else { |
| Some(format!("{prefix}{ty_str};")) |
| } |
| } |
| |
| // FIXME(calebcartwright) - This is a hack around a bug in the handling of TyKind::ImplTrait. |
| // This should be removed once that bug is resolved, with the type alias formatting using the |
| // defined Ty for the RHS directly. |
| // https://github.com/rust-lang/rustfmt/issues/4373 |
| // https://github.com/rust-lang/rustfmt/issues/5027 |
| struct OpaqueType<'a> { |
| bounds: &'a ast::GenericBounds, |
| } |
| |
| impl<'a> Rewrite for OpaqueType<'a> { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| let shape = shape.offset_left(5)?; // `impl ` |
| self.bounds |
| .rewrite(context, shape) |
| .map(|s| format!("impl {}", s)) |
| } |
| } |
| |
| impl Rewrite for ast::FnRetTy { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| match *self { |
| ast::FnRetTy::Default(_) => Some(String::new()), |
| ast::FnRetTy::Ty(ref ty) => { |
| if context.config.version() == Version::One |
| || context.config.indent_style() == IndentStyle::Visual |
| { |
| let inner_width = shape.width.checked_sub(3)?; |
| return ty |
| .rewrite(context, Shape::legacy(inner_width, shape.indent + 3)) |
| .map(|r| format!("-> {}", r)); |
| } |
| |
| ty.rewrite(context, shape.offset_left(3)?) |
| .map(|s| format!("-> {}", s)) |
| } |
| } |
| } |
| } |
| |
| fn is_empty_infer(ty: &ast::Ty, pat_span: Span) -> bool { |
| match ty.kind { |
| ast::TyKind::Infer => ty.span.hi() == pat_span.hi(), |
| _ => false, |
| } |
| } |
| |
| /// Recover any missing comments between the param and the type. |
| /// |
| /// # Returns |
| /// |
| /// A 2-len tuple with the comment before the colon in first position, and the comment after the |
| /// colon in second position. |
| fn get_missing_param_comments( |
| context: &RewriteContext<'_>, |
| pat_span: Span, |
| ty_span: Span, |
| shape: Shape, |
| ) -> (String, String) { |
| let missing_comment_span = mk_sp(pat_span.hi(), ty_span.lo()); |
| |
| let span_before_colon = { |
| let missing_comment_span_hi = context |
| .snippet_provider |
| .span_before(missing_comment_span, ":"); |
| mk_sp(pat_span.hi(), missing_comment_span_hi) |
| }; |
| let span_after_colon = { |
| let missing_comment_span_lo = context |
| .snippet_provider |
| .span_after(missing_comment_span, ":"); |
| mk_sp(missing_comment_span_lo, ty_span.lo()) |
| }; |
| |
| let comment_before_colon = rewrite_missing_comment(span_before_colon, shape, context) |
| .filter(|comment| !comment.is_empty()) |
| .map_or(String::new(), |comment| format!(" {}", comment)); |
| let comment_after_colon = rewrite_missing_comment(span_after_colon, shape, context) |
| .filter(|comment| !comment.is_empty()) |
| .map_or(String::new(), |comment| format!("{} ", comment)); |
| (comment_before_colon, comment_after_colon) |
| } |
| |
| impl Rewrite for ast::Param { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| let param_attrs_result = self |
| .attrs |
| .rewrite(context, Shape::legacy(shape.width, shape.indent))?; |
| // N.B. Doc comments aren't typically valid syntax, but could appear |
| // in the presence of certain macros - https://github.com/rust-lang/rustfmt/issues/4936 |
| let (span, has_multiple_attr_lines, has_doc_comments) = if !self.attrs.is_empty() { |
| let num_attrs = self.attrs.len(); |
| ( |
| mk_sp(self.attrs[num_attrs - 1].span.hi(), self.pat.span.lo()), |
| param_attrs_result.contains('\n'), |
| self.attrs.iter().any(|a| a.is_doc_comment()), |
| ) |
| } else { |
| (mk_sp(self.span.lo(), self.span.lo()), false, false) |
| }; |
| |
| if let Some(ref explicit_self) = self.to_self() { |
| rewrite_explicit_self( |
| context, |
| explicit_self, |
| ¶m_attrs_result, |
| span, |
| shape, |
| has_multiple_attr_lines, |
| ) |
| } else if is_named_param(self) { |
| let param_name = &self |
| .pat |
| .rewrite(context, Shape::legacy(shape.width, shape.indent))?; |
| let mut result = combine_strs_with_missing_comments( |
| context, |
| ¶m_attrs_result, |
| param_name, |
| span, |
| shape, |
| !has_multiple_attr_lines && !has_doc_comments, |
| )?; |
| |
| if !is_empty_infer(&*self.ty, self.pat.span) { |
| let (before_comment, after_comment) = |
| get_missing_param_comments(context, self.pat.span, self.ty.span, shape); |
| result.push_str(&before_comment); |
| result.push_str(colon_spaces(context.config)); |
| result.push_str(&after_comment); |
| let overhead = last_line_width(&result); |
| let max_width = shape.width.checked_sub(overhead)?; |
| if let Some(ty_str) = self |
| .ty |
| .rewrite(context, Shape::legacy(max_width, shape.indent)) |
| { |
| result.push_str(&ty_str); |
| } else { |
| let prev_str = if param_attrs_result.is_empty() { |
| param_attrs_result |
| } else { |
| param_attrs_result + &shape.to_string_with_newline(context.config) |
| }; |
| |
| result = combine_strs_with_missing_comments( |
| context, |
| &prev_str, |
| param_name, |
| span, |
| shape, |
| !has_multiple_attr_lines, |
| )?; |
| result.push_str(&before_comment); |
| result.push_str(colon_spaces(context.config)); |
| result.push_str(&after_comment); |
| let overhead = last_line_width(&result); |
| let max_width = shape.width.checked_sub(overhead)?; |
| let ty_str = self |
| .ty |
| .rewrite(context, Shape::legacy(max_width, shape.indent))?; |
| result.push_str(&ty_str); |
| } |
| } |
| |
| Some(result) |
| } else { |
| self.ty.rewrite(context, shape) |
| } |
| } |
| } |
| |
| fn rewrite_explicit_self( |
| context: &RewriteContext<'_>, |
| explicit_self: &ast::ExplicitSelf, |
| param_attrs: &str, |
| span: Span, |
| shape: Shape, |
| has_multiple_attr_lines: bool, |
| ) -> Option<String> { |
| match explicit_self.node { |
| ast::SelfKind::Region(lt, m) => { |
| let mut_str = format_mutability(m); |
| match lt { |
| Some(ref l) => { |
| let lifetime_str = l.rewrite( |
| context, |
| Shape::legacy(context.config.max_width(), Indent::empty()), |
| )?; |
| Some(combine_strs_with_missing_comments( |
| context, |
| param_attrs, |
| &format!("&{lifetime_str} {mut_str}self"), |
| span, |
| shape, |
| !has_multiple_attr_lines, |
| )?) |
| } |
| None => Some(combine_strs_with_missing_comments( |
| context, |
| param_attrs, |
| &format!("&{mut_str}self"), |
| span, |
| shape, |
| !has_multiple_attr_lines, |
| )?), |
| } |
| } |
| ast::SelfKind::Explicit(ref ty, mutability) => { |
| let type_str = ty.rewrite( |
| context, |
| Shape::legacy(context.config.max_width(), Indent::empty()), |
| )?; |
| |
| Some(combine_strs_with_missing_comments( |
| context, |
| param_attrs, |
| &format!("{}self: {}", format_mutability(mutability), type_str), |
| span, |
| shape, |
| !has_multiple_attr_lines, |
| )?) |
| } |
| ast::SelfKind::Value(mutability) => Some(combine_strs_with_missing_comments( |
| context, |
| param_attrs, |
| &format!("{}self", format_mutability(mutability)), |
| span, |
| shape, |
| !has_multiple_attr_lines, |
| )?), |
| } |
| } |
| |
| pub(crate) fn span_lo_for_param(param: &ast::Param) -> BytePos { |
| if param.attrs.is_empty() { |
| if is_named_param(param) { |
| param.pat.span.lo() |
| } else { |
| param.ty.span.lo() |
| } |
| } else { |
| param.attrs[0].span.lo() |
| } |
| } |
| |
| pub(crate) fn span_hi_for_param(context: &RewriteContext<'_>, param: &ast::Param) -> BytePos { |
| match param.ty.kind { |
| ast::TyKind::Infer if context.snippet(param.ty.span) == "_" => param.ty.span.hi(), |
| ast::TyKind::Infer if is_named_param(param) => param.pat.span.hi(), |
| _ => param.ty.span.hi(), |
| } |
| } |
| |
| pub(crate) fn is_named_param(param: &ast::Param) -> bool { |
| if let ast::PatKind::Ident(_, ident, _) = param.pat.kind { |
| ident.name != symbol::kw::Empty |
| } else { |
| true |
| } |
| } |
| |
| #[derive(Copy, Clone, Debug, PartialEq, Eq)] |
| pub(crate) enum FnBraceStyle { |
| SameLine, |
| NextLine, |
| None, |
| } |
| |
| // Return type is (result, force_new_line_for_brace) |
| fn rewrite_fn_base( |
| context: &RewriteContext<'_>, |
| indent: Indent, |
| ident: symbol::Ident, |
| fn_sig: &FnSig<'_>, |
| span: Span, |
| fn_brace_style: FnBraceStyle, |
| ) -> Option<(String, bool, bool)> { |
| let mut force_new_line_for_brace = false; |
| |
| let where_clause = &fn_sig.generics.where_clause; |
| |
| let mut result = String::with_capacity(1024); |
| result.push_str(&fn_sig.to_str(context)); |
| |
| // fn foo |
| result.push_str("fn "); |
| |
| // Generics. |
| let overhead = if let FnBraceStyle::SameLine = fn_brace_style { |
| // 4 = `() {` |
| 4 |
| } else { |
| // 2 = `()` |
| 2 |
| }; |
| let used_width = last_line_used_width(&result, indent.width()); |
| let one_line_budget = context.budget(used_width + overhead); |
| let shape = Shape { |
| width: one_line_budget, |
| indent, |
| offset: used_width, |
| }; |
| let fd = fn_sig.decl; |
| let generics_str = rewrite_generics( |
| context, |
| rewrite_ident(context, ident), |
| &fn_sig.generics, |
| shape, |
| )?; |
| result.push_str(&generics_str); |
| |
| let snuggle_angle_bracket = generics_str |
| .lines() |
| .last() |
| .map_or(false, |l| l.trim_start().len() == 1); |
| |
| // Note that the width and indent don't really matter, we'll re-layout the |
| // return type later anyway. |
| let ret_str = fd |
| .output |
| .rewrite(context, Shape::indented(indent, context.config))?; |
| |
| let multi_line_ret_str = ret_str.contains('\n'); |
| let ret_str_len = if multi_line_ret_str { 0 } else { ret_str.len() }; |
| |
| // Params. |
| let (one_line_budget, multi_line_budget, mut param_indent) = compute_budgets_for_params( |
| context, |
| &result, |
| indent, |
| ret_str_len, |
| fn_brace_style, |
| multi_line_ret_str, |
| )?; |
| |
| debug!( |
| "rewrite_fn_base: one_line_budget: {}, multi_line_budget: {}, param_indent: {:?}", |
| one_line_budget, multi_line_budget, param_indent |
| ); |
| |
| result.push('('); |
| // Check if vertical layout was forced. |
| if one_line_budget == 0 |
| && !snuggle_angle_bracket |
| && context.config.indent_style() == IndentStyle::Visual |
| { |
| result.push_str(¶m_indent.to_string_with_newline(context.config)); |
| } |
| |
| let params_end = if fd.inputs.is_empty() { |
| context |
| .snippet_provider |
| .span_after(mk_sp(fn_sig.generics.span.hi(), span.hi()), ")") |
| } else { |
| let last_span = mk_sp(fd.inputs[fd.inputs.len() - 1].span().hi(), span.hi()); |
| context.snippet_provider.span_after(last_span, ")") |
| }; |
| let params_span = mk_sp( |
| context |
| .snippet_provider |
| .span_after(mk_sp(fn_sig.generics.span.hi(), span.hi()), "("), |
| params_end, |
| ); |
| let param_str = rewrite_params( |
| context, |
| &fd.inputs, |
| one_line_budget, |
| multi_line_budget, |
| indent, |
| param_indent, |
| params_span, |
| fd.c_variadic(), |
| )?; |
| |
| let put_params_in_block = match context.config.indent_style() { |
| IndentStyle::Block => param_str.contains('\n') || param_str.len() > one_line_budget, |
| _ => false, |
| } && !fd.inputs.is_empty(); |
| |
| let mut params_last_line_contains_comment = false; |
| let mut no_params_and_over_max_width = false; |
| |
| if put_params_in_block { |
| param_indent = indent.block_indent(context.config); |
| result.push_str(¶m_indent.to_string_with_newline(context.config)); |
| result.push_str(¶m_str); |
| result.push_str(&indent.to_string_with_newline(context.config)); |
| result.push(')'); |
| } else { |
| result.push_str(¶m_str); |
| let used_width = last_line_used_width(&result, indent.width()) + first_line_width(&ret_str); |
| // Put the closing brace on the next line if it overflows the max width. |
| // 1 = `)` |
| let closing_paren_overflow_max_width = |
| fd.inputs.is_empty() && used_width + 1 > context.config.max_width(); |
| // If the last line of params contains comment, we cannot put the closing paren |
| // on the same line. |
| params_last_line_contains_comment = param_str |
| .lines() |
| .last() |
| .map_or(false, |last_line| last_line.contains("//")); |
| |
| if context.config.version() == Version::Two { |
| if closing_paren_overflow_max_width { |
| result.push(')'); |
| result.push_str(&indent.to_string_with_newline(context.config)); |
| no_params_and_over_max_width = true; |
| } else if params_last_line_contains_comment { |
| result.push_str(&indent.to_string_with_newline(context.config)); |
| result.push(')'); |
| no_params_and_over_max_width = true; |
| } else { |
| result.push(')'); |
| } |
| } else { |
| if closing_paren_overflow_max_width || params_last_line_contains_comment { |
| result.push_str(&indent.to_string_with_newline(context.config)); |
| } |
| result.push(')'); |
| } |
| } |
| |
| // Return type. |
| if let ast::FnRetTy::Ty(..) = fd.output { |
| let ret_should_indent = match context.config.indent_style() { |
| // If our params are block layout then we surely must have space. |
| IndentStyle::Block if put_params_in_block || fd.inputs.is_empty() => false, |
| _ if params_last_line_contains_comment => false, |
| _ if result.contains('\n') || multi_line_ret_str => true, |
| _ => { |
| // If the return type would push over the max width, then put the return type on |
| // a new line. With the +1 for the signature length an additional space between |
| // the closing parenthesis of the param and the arrow '->' is considered. |
| let mut sig_length = result.len() + indent.width() + ret_str_len + 1; |
| |
| // If there is no where-clause, take into account the space after the return type |
| // and the brace. |
| if where_clause.predicates.is_empty() { |
| sig_length += 2; |
| } |
| |
| sig_length > context.config.max_width() |
| } |
| }; |
| let ret_shape = if ret_should_indent { |
| if context.config.version() == Version::One |
| || context.config.indent_style() == IndentStyle::Visual |
| { |
| let indent = if param_str.is_empty() { |
| // Aligning with non-existent params looks silly. |
| force_new_line_for_brace = true; |
| indent + 4 |
| } else { |
| // FIXME: we might want to check that using the param indent |
| // doesn't blow our budget, and if it does, then fallback to |
| // the where-clause indent. |
| param_indent |
| }; |
| |
| result.push_str(&indent.to_string_with_newline(context.config)); |
| Shape::indented(indent, context.config) |
| } else { |
| let mut ret_shape = Shape::indented(indent, context.config); |
| if param_str.is_empty() { |
| // Aligning with non-existent params looks silly. |
| force_new_line_for_brace = true; |
| ret_shape = if context.use_block_indent() { |
| ret_shape.offset_left(4).unwrap_or(ret_shape) |
| } else { |
| ret_shape.indent = ret_shape.indent + 4; |
| ret_shape |
| }; |
| } |
| |
| result.push_str(&ret_shape.indent.to_string_with_newline(context.config)); |
| ret_shape |
| } |
| } else { |
| if context.config.version() == Version::Two { |
| if !param_str.is_empty() || !no_params_and_over_max_width { |
| result.push(' '); |
| } |
| } else { |
| result.push(' '); |
| } |
| |
| let ret_shape = Shape::indented(indent, context.config); |
| ret_shape |
| .offset_left(last_line_width(&result)) |
| .unwrap_or(ret_shape) |
| }; |
| |
| if multi_line_ret_str || ret_should_indent { |
| // Now that we know the proper indent and width, we need to |
| // re-layout the return type. |
| let ret_str = fd.output.rewrite(context, ret_shape)?; |
| result.push_str(&ret_str); |
| } else { |
| result.push_str(&ret_str); |
| } |
| |
| // Comment between return type and the end of the decl. |
| let snippet_lo = fd.output.span().hi(); |
| if where_clause.predicates.is_empty() { |
| let snippet_hi = span.hi(); |
| let snippet = context.snippet(mk_sp(snippet_lo, snippet_hi)); |
| // Try to preserve the layout of the original snippet. |
| let original_starts_with_newline = snippet |
| .find(|c| c != ' ') |
| .map_or(false, |i| starts_with_newline(&snippet[i..])); |
| let original_ends_with_newline = snippet |
| .rfind(|c| c != ' ') |
| .map_or(false, |i| snippet[i..].ends_with('\n')); |
| let snippet = snippet.trim(); |
| if !snippet.is_empty() { |
| result.push(if original_starts_with_newline { |
| '\n' |
| } else { |
| ' ' |
| }); |
| result.push_str(snippet); |
| if original_ends_with_newline { |
| force_new_line_for_brace = true; |
| } |
| } |
| } |
| } |
| |
| let pos_before_where = match fd.output { |
| ast::FnRetTy::Default(..) => params_span.hi(), |
| ast::FnRetTy::Ty(ref ty) => ty.span.hi(), |
| }; |
| |
| let is_params_multi_lined = param_str.contains('\n'); |
| |
| let space = if put_params_in_block && ret_str.is_empty() { |
| WhereClauseSpace::Space |
| } else { |
| WhereClauseSpace::Newline |
| }; |
| let mut option = WhereClauseOption::new(fn_brace_style == FnBraceStyle::None, space); |
| if is_params_multi_lined { |
| option.veto_single_line(); |
| } |
| let where_clause_str = rewrite_where_clause( |
| context, |
| &where_clause.predicates, |
| where_clause.span, |
| context.config.brace_style(), |
| Shape::indented(indent, context.config), |
| true, |
| "{", |
| Some(span.hi()), |
| pos_before_where, |
| option, |
| )?; |
| // If there are neither where-clause nor return type, we may be missing comments between |
| // params and `{`. |
| if where_clause_str.is_empty() { |
| if let ast::FnRetTy::Default(ret_span) = fd.output { |
| match recover_missing_comment_in_span( |
| // from after the closing paren to right before block or semicolon |
| mk_sp(ret_span.lo(), span.hi()), |
| shape, |
| context, |
| last_line_width(&result), |
| ) { |
| Some(ref missing_comment) if !missing_comment.is_empty() => { |
| result.push_str(missing_comment); |
| force_new_line_for_brace = true; |
| } |
| _ => (), |
| } |
| } |
| } |
| |
| result.push_str(&where_clause_str); |
| |
| let ends_with_comment = last_line_contains_single_line_comment(&result); |
| force_new_line_for_brace |= ends_with_comment; |
| force_new_line_for_brace |= |
| is_params_multi_lined && context.config.where_single_line() && !where_clause_str.is_empty(); |
| Some((result, ends_with_comment, force_new_line_for_brace)) |
| } |
| |
| /// Kind of spaces to put before `where`. |
| #[derive(Copy, Clone)] |
| enum WhereClauseSpace { |
| /// A single space. |
| Space, |
| /// A new line. |
| Newline, |
| /// Nothing. |
| None, |
| } |
| |
| #[derive(Copy, Clone)] |
| struct WhereClauseOption { |
| suppress_comma: bool, // Force no trailing comma |
| snuggle: WhereClauseSpace, |
| allow_single_line: bool, // Try single line where-clause instead of vertical layout |
| veto_single_line: bool, // Disallow a single-line where-clause. |
| } |
| |
| impl WhereClauseOption { |
| fn new(suppress_comma: bool, snuggle: WhereClauseSpace) -> WhereClauseOption { |
| WhereClauseOption { |
| suppress_comma, |
| snuggle, |
| allow_single_line: false, |
| veto_single_line: false, |
| } |
| } |
| |
| fn snuggled(current: &str) -> WhereClauseOption { |
| WhereClauseOption { |
| suppress_comma: false, |
| snuggle: if last_line_width(current) == 1 { |
| WhereClauseSpace::Space |
| } else { |
| WhereClauseSpace::Newline |
| }, |
| allow_single_line: false, |
| veto_single_line: false, |
| } |
| } |
| |
| fn suppress_comma(&mut self) { |
| self.suppress_comma = true |
| } |
| |
| fn allow_single_line(&mut self) { |
| self.allow_single_line = true |
| } |
| |
| fn snuggle(&mut self) { |
| self.snuggle = WhereClauseSpace::Space |
| } |
| |
| fn veto_single_line(&mut self) { |
| self.veto_single_line = true; |
| } |
| } |
| |
| fn rewrite_params( |
| context: &RewriteContext<'_>, |
| params: &[ast::Param], |
| one_line_budget: usize, |
| multi_line_budget: usize, |
| indent: Indent, |
| param_indent: Indent, |
| span: Span, |
| variadic: bool, |
| ) -> Option<String> { |
| if params.is_empty() { |
| let comment = context |
| .snippet(mk_sp( |
| span.lo(), |
| // to remove ')' |
| span.hi() - BytePos(1), |
| )) |
| .trim(); |
| return Some(comment.to_owned()); |
| } |
| let param_items: Vec<_> = itemize_list( |
| context.snippet_provider, |
| params.iter(), |
| ")", |
| ",", |
| |param| span_lo_for_param(param), |
| |param| param.ty.span.hi(), |
| |param| { |
| param |
| .rewrite(context, Shape::legacy(multi_line_budget, param_indent)) |
| .or_else(|| Some(context.snippet(param.span()).to_owned())) |
| }, |
| span.lo(), |
| span.hi(), |
| false, |
| ) |
| .collect(); |
| |
| let tactic = definitive_tactic( |
| ¶m_items, |
| context |
| .config |
| .fn_params_layout() |
| .to_list_tactic(param_items.len()), |
| Separator::Comma, |
| one_line_budget, |
| ); |
| let budget = match tactic { |
| DefinitiveListTactic::Horizontal => one_line_budget, |
| _ => multi_line_budget, |
| }; |
| let indent = match context.config.indent_style() { |
| IndentStyle::Block => indent.block_indent(context.config), |
| IndentStyle::Visual => param_indent, |
| }; |
| let trailing_separator = if variadic { |
| SeparatorTactic::Never |
| } else { |
| match context.config.indent_style() { |
| IndentStyle::Block => context.config.trailing_comma(), |
| IndentStyle::Visual => SeparatorTactic::Never, |
| } |
| }; |
| let fmt = ListFormatting::new(Shape::legacy(budget, indent), context.config) |
| .tactic(tactic) |
| .trailing_separator(trailing_separator) |
| .ends_with_newline(tactic.ends_with_newline(context.config.indent_style())) |
| .preserve_newline(true); |
| write_list(¶m_items, &fmt) |
| } |
| |
| fn compute_budgets_for_params( |
| context: &RewriteContext<'_>, |
| result: &str, |
| indent: Indent, |
| ret_str_len: usize, |
| fn_brace_style: FnBraceStyle, |
| force_vertical_layout: bool, |
| ) -> Option<(usize, usize, Indent)> { |
| debug!( |
| "compute_budgets_for_params {} {:?}, {}, {:?}", |
| result.len(), |
| indent, |
| ret_str_len, |
| fn_brace_style, |
| ); |
| // Try keeping everything on the same line. |
| if !result.contains('\n') && !force_vertical_layout { |
| // 2 = `()`, 3 = `() `, space is before ret_string. |
| let overhead = if ret_str_len == 0 { 2 } else { 3 }; |
| let mut used_space = indent.width() + result.len() + ret_str_len + overhead; |
| match fn_brace_style { |
| FnBraceStyle::None => used_space += 1, // 1 = `;` |
| FnBraceStyle::SameLine => used_space += 2, // 2 = `{}` |
| FnBraceStyle::NextLine => (), |
| } |
| let one_line_budget = context.budget(used_space); |
| |
| if one_line_budget > 0 { |
| // 4 = "() {".len() |
| let (indent, multi_line_budget) = match context.config.indent_style() { |
| IndentStyle::Block => { |
| let indent = indent.block_indent(context.config); |
| (indent, context.budget(indent.width() + 1)) |
| } |
| IndentStyle::Visual => { |
| let indent = indent + result.len() + 1; |
| let multi_line_overhead = match fn_brace_style { |
| FnBraceStyle::SameLine => 4, |
| _ => 2, |
| } + indent.width(); |
| (indent, context.budget(multi_line_overhead)) |
| } |
| }; |
| |
| return Some((one_line_budget, multi_line_budget, indent)); |
| } |
| } |
| |
| // Didn't work. we must force vertical layout and put params on a newline. |
| let new_indent = indent.block_indent(context.config); |
| let used_space = match context.config.indent_style() { |
| // 1 = `,` |
| IndentStyle::Block => new_indent.width() + 1, |
| // Account for `)` and possibly ` {`. |
| IndentStyle::Visual => new_indent.width() + if ret_str_len == 0 { 1 } else { 3 }, |
| }; |
| Some((0, context.budget(used_space), new_indent)) |
| } |
| |
| fn newline_for_brace(config: &Config, where_clause: &ast::WhereClause) -> FnBraceStyle { |
| let predicate_count = where_clause.predicates.len(); |
| |
| if config.where_single_line() && predicate_count == 1 { |
| return FnBraceStyle::SameLine; |
| } |
| let brace_style = config.brace_style(); |
| |
| let use_next_line = brace_style == BraceStyle::AlwaysNextLine |
| || (brace_style == BraceStyle::SameLineWhere && predicate_count > 0); |
| if use_next_line { |
| FnBraceStyle::NextLine |
| } else { |
| FnBraceStyle::SameLine |
| } |
| } |
| |
| fn rewrite_generics( |
| context: &RewriteContext<'_>, |
| ident: &str, |
| generics: &ast::Generics, |
| shape: Shape, |
| ) -> Option<String> { |
| // FIXME: convert bounds to where-clauses where they get too big or if |
| // there is a where-clause at all. |
| |
| if generics.params.is_empty() { |
| return Some(ident.to_owned()); |
| } |
| |
| let params = generics.params.iter(); |
| overflow::rewrite_with_angle_brackets(context, ident, params, shape, generics.span) |
| } |
| |
| fn generics_shape_from_config(config: &Config, shape: Shape, offset: usize) -> Option<Shape> { |
| match config.indent_style() { |
| IndentStyle::Visual => shape.visual_indent(1 + offset).sub_width(offset + 2), |
| IndentStyle::Block => { |
| // 1 = "," |
| shape |
| .block() |
| .block_indent(config.tab_spaces()) |
| .with_max_width(config) |
| .sub_width(1) |
| } |
| } |
| } |
| |
| fn rewrite_where_clause_rfc_style( |
| context: &RewriteContext<'_>, |
| predicates: &[ast::WherePredicate], |
| where_span: Span, |
| shape: Shape, |
| terminator: &str, |
| span_end: Option<BytePos>, |
| span_end_before_where: BytePos, |
| where_clause_option: WhereClauseOption, |
| ) -> Option<String> { |
| let (where_keyword, allow_single_line) = rewrite_where_keyword( |
| context, |
| predicates, |
| where_span, |
| shape, |
| span_end_before_where, |
| where_clause_option, |
| )?; |
| |
| // 1 = `,` |
| let clause_shape = shape |
| .block() |
| .with_max_width(context.config) |
| .block_left(context.config.tab_spaces())? |
| .sub_width(1)?; |
| let force_single_line = context.config.where_single_line() |
| && predicates.len() == 1 |
| && !where_clause_option.veto_single_line; |
| |
| let preds_str = rewrite_bounds_on_where_clause( |
| context, |
| predicates, |
| clause_shape, |
| terminator, |
| span_end, |
| where_clause_option, |
| force_single_line, |
| )?; |
| |
| // 6 = `where ` |
| let clause_sep = |
| if allow_single_line && !preds_str.contains('\n') && 6 + preds_str.len() <= shape.width |
| || force_single_line |
| { |
| Cow::from(" ") |
| } else { |
| clause_shape.indent.to_string_with_newline(context.config) |
| }; |
| |
| Some(format!("{where_keyword}{clause_sep}{preds_str}")) |
| } |
| |
| /// Rewrite `where` and comment around it. |
| fn rewrite_where_keyword( |
| context: &RewriteContext<'_>, |
| predicates: &[ast::WherePredicate], |
| where_span: Span, |
| shape: Shape, |
| span_end_before_where: BytePos, |
| where_clause_option: WhereClauseOption, |
| ) -> Option<(String, bool)> { |
| let block_shape = shape.block().with_max_width(context.config); |
| // 1 = `,` |
| let clause_shape = block_shape |
| .block_left(context.config.tab_spaces())? |
| .sub_width(1)?; |
| |
| let comment_separator = |comment: &str, shape: Shape| { |
| if comment.is_empty() { |
| Cow::from("") |
| } else { |
| shape.indent.to_string_with_newline(context.config) |
| } |
| }; |
| |
| let (span_before, span_after) = |
| missing_span_before_after_where(span_end_before_where, predicates, where_span); |
| let (comment_before, comment_after) = |
| rewrite_comments_before_after_where(context, span_before, span_after, shape)?; |
| |
| let starting_newline = match where_clause_option.snuggle { |
| WhereClauseSpace::Space if comment_before.is_empty() => Cow::from(" "), |
| WhereClauseSpace::None => Cow::from(""), |
| _ => block_shape.indent.to_string_with_newline(context.config), |
| }; |
| |
| let newline_before_where = comment_separator(&comment_before, shape); |
| let newline_after_where = comment_separator(&comment_after, clause_shape); |
| let result = format!( |
| "{starting_newline}{comment_before}{newline_before_where}where\ |
| {newline_after_where}{comment_after}" |
| ); |
| let allow_single_line = where_clause_option.allow_single_line |
| && comment_before.is_empty() |
| && comment_after.is_empty(); |
| |
| Some((result, allow_single_line)) |
| } |
| |
| /// Rewrite bounds on a where clause. |
| fn rewrite_bounds_on_where_clause( |
| context: &RewriteContext<'_>, |
| predicates: &[ast::WherePredicate], |
| shape: Shape, |
| terminator: &str, |
| span_end: Option<BytePos>, |
| where_clause_option: WhereClauseOption, |
| force_single_line: bool, |
| ) -> Option<String> { |
| let span_start = predicates[0].span().lo(); |
| // If we don't have the start of the next span, then use the end of the |
| // predicates, but that means we miss comments. |
| let len = predicates.len(); |
| let end_of_preds = predicates[len - 1].span().hi(); |
| let span_end = span_end.unwrap_or(end_of_preds); |
| let items = itemize_list( |
| context.snippet_provider, |
| predicates.iter(), |
| terminator, |
| ",", |
| |pred| pred.span().lo(), |
| |pred| pred.span().hi(), |
| |pred| pred.rewrite(context, shape), |
| span_start, |
| span_end, |
| false, |
| ); |
| let comma_tactic = if where_clause_option.suppress_comma || force_single_line { |
| SeparatorTactic::Never |
| } else { |
| context.config.trailing_comma() |
| }; |
| |
| // shape should be vertical only and only if we have `force_single_line` option enabled |
| // and the number of items of the where-clause is equal to 1 |
| let shape_tactic = if force_single_line { |
| DefinitiveListTactic::Horizontal |
| } else { |
| DefinitiveListTactic::Vertical |
| }; |
| |
| let preserve_newline = context.config.version() == Version::One; |
| |
| let fmt = ListFormatting::new(shape, context.config) |
| .tactic(shape_tactic) |
| .trailing_separator(comma_tactic) |
| .preserve_newline(preserve_newline); |
| write_list(&items.collect::<Vec<_>>(), &fmt) |
| } |
| |
| fn rewrite_where_clause( |
| context: &RewriteContext<'_>, |
| predicates: &[ast::WherePredicate], |
| where_span: Span, |
| brace_style: BraceStyle, |
| shape: Shape, |
| on_new_line: bool, |
| terminator: &str, |
| span_end: Option<BytePos>, |
| span_end_before_where: BytePos, |
| where_clause_option: WhereClauseOption, |
| ) -> Option<String> { |
| if predicates.is_empty() { |
| return Some(String::new()); |
| } |
| |
| if context.config.indent_style() == IndentStyle::Block { |
| return rewrite_where_clause_rfc_style( |
| context, |
| predicates, |
| where_span, |
| shape, |
| terminator, |
| span_end, |
| span_end_before_where, |
| where_clause_option, |
| ); |
| } |
| |
| let extra_indent = Indent::new(context.config.tab_spaces(), 0); |
| |
| let offset = match context.config.indent_style() { |
| IndentStyle::Block => shape.indent + extra_indent.block_indent(context.config), |
| // 6 = "where ".len() |
| IndentStyle::Visual => shape.indent + extra_indent + 6, |
| }; |
| // FIXME: if indent_style != Visual, then the budgets below might |
| // be out by a char or two. |
| |
| let budget = context.config.max_width() - offset.width(); |
| let span_start = predicates[0].span().lo(); |
| // If we don't have the start of the next span, then use the end of the |
| // predicates, but that means we miss comments. |
| let len = predicates.len(); |
| let end_of_preds = predicates[len - 1].span().hi(); |
| let span_end = span_end.unwrap_or(end_of_preds); |
| let items = itemize_list( |
| context.snippet_provider, |
| predicates.iter(), |
| terminator, |
| ",", |
| |pred| pred.span().lo(), |
| |pred| pred.span().hi(), |
| |pred| pred.rewrite(context, Shape::legacy(budget, offset)), |
| span_start, |
| span_end, |
| false, |
| ); |
| let item_vec = items.collect::<Vec<_>>(); |
| // FIXME: we don't need to collect here |
| let tactic = definitive_tactic(&item_vec, ListTactic::Vertical, Separator::Comma, budget); |
| |
| let mut comma_tactic = context.config.trailing_comma(); |
| // Kind of a hack because we don't usually have trailing commas in where-clauses. |
| if comma_tactic == SeparatorTactic::Vertical || where_clause_option.suppress_comma { |
| comma_tactic = SeparatorTactic::Never; |
| } |
| |
| let fmt = ListFormatting::new(Shape::legacy(budget, offset), context.config) |
| .tactic(tactic) |
| .trailing_separator(comma_tactic) |
| .ends_with_newline(tactic.ends_with_newline(context.config.indent_style())) |
| .preserve_newline(true); |
| let preds_str = write_list(&item_vec, &fmt)?; |
| |
| let end_length = if terminator == "{" { |
| // If the brace is on the next line we don't need to count it otherwise it needs two |
| // characters " {" |
| match brace_style { |
| BraceStyle::AlwaysNextLine | BraceStyle::SameLineWhere => 0, |
| BraceStyle::PreferSameLine => 2, |
| } |
| } else if terminator == "=" { |
| 2 |
| } else { |
| terminator.len() |
| }; |
| if on_new_line |
| || preds_str.contains('\n') |
| || shape.indent.width() + " where ".len() + preds_str.len() + end_length > shape.width |
| { |
| Some(format!( |
| "\n{}where {}", |
| (shape.indent + extra_indent).to_string(context.config), |
| preds_str |
| )) |
| } else { |
| Some(format!(" where {preds_str}")) |
| } |
| } |
| |
| fn missing_span_before_after_where( |
| before_item_span_end: BytePos, |
| predicates: &[ast::WherePredicate], |
| where_span: Span, |
| ) -> (Span, Span) { |
| let missing_span_before = mk_sp(before_item_span_end, where_span.lo()); |
| // 5 = `where` |
| let pos_after_where = where_span.lo() + BytePos(5); |
| let missing_span_after = mk_sp(pos_after_where, predicates[0].span().lo()); |
| (missing_span_before, missing_span_after) |
| } |
| |
| fn rewrite_comments_before_after_where( |
| context: &RewriteContext<'_>, |
| span_before_where: Span, |
| span_after_where: Span, |
| shape: Shape, |
| ) -> Option<(String, String)> { |
| let before_comment = rewrite_missing_comment(span_before_where, shape, context)?; |
| let after_comment = rewrite_missing_comment( |
| span_after_where, |
| shape.block_indent(context.config.tab_spaces()), |
| context, |
| )?; |
| Some((before_comment, after_comment)) |
| } |
| |
| fn format_header( |
| context: &RewriteContext<'_>, |
| item_name: &str, |
| ident: symbol::Ident, |
| vis: &ast::Visibility, |
| offset: Indent, |
| ) -> String { |
| let mut result = String::with_capacity(128); |
| let shape = Shape::indented(offset, context.config); |
| |
| result.push_str(format_visibility(context, vis).trim()); |
| |
| // Check for a missing comment between the visibility and the item name. |
| let after_vis = vis.span.hi(); |
| if let Some(before_item_name) = context |
| .snippet_provider |
| .opt_span_before(mk_sp(vis.span.lo(), ident.span.hi()), item_name.trim()) |
| { |
| let missing_span = mk_sp(after_vis, before_item_name); |
| if let Some(result_with_comment) = combine_strs_with_missing_comments( |
| context, |
| &result, |
| item_name, |
| missing_span, |
| shape, |
| /* allow_extend */ true, |
| ) { |
| result = result_with_comment; |
| } |
| } |
| |
| result.push_str(rewrite_ident(context, ident)); |
| |
| result |
| } |
| |
| #[derive(PartialEq, Eq, Clone, Copy)] |
| enum BracePos { |
| None, |
| Auto, |
| ForceSameLine, |
| } |
| |
| fn format_generics( |
| context: &RewriteContext<'_>, |
| generics: &ast::Generics, |
| brace_style: BraceStyle, |
| brace_pos: BracePos, |
| offset: Indent, |
| span: Span, |
| used_width: usize, |
| ) -> Option<String> { |
| let shape = Shape::legacy(context.budget(used_width + offset.width()), offset); |
| let mut result = rewrite_generics(context, "", generics, shape)?; |
| |
| // If the generics are not parameterized then generics.span.hi() == 0, |
| // so we use span.lo(), which is the position after `struct Foo`. |
| let span_end_before_where = if !generics.params.is_empty() { |
| generics.span.hi() |
| } else { |
| span.lo() |
| }; |
| let (same_line_brace, missed_comments) = if !generics.where_clause.predicates.is_empty() { |
| let budget = context.budget(last_line_used_width(&result, offset.width())); |
| let mut option = WhereClauseOption::snuggled(&result); |
| if brace_pos == BracePos::None { |
| option.suppress_comma = true; |
| } |
| let where_clause_str = rewrite_where_clause( |
| context, |
| &generics.where_clause.predicates, |
| generics.where_clause.span, |
| brace_style, |
| Shape::legacy(budget, offset.block_only()), |
| true, |
| "{", |
| Some(span.hi()), |
| span_end_before_where, |
| option, |
| )?; |
| result.push_str(&where_clause_str); |
| ( |
| brace_pos == BracePos::ForceSameLine || brace_style == BraceStyle::PreferSameLine, |
| // missed comments are taken care of in #rewrite_where_clause |
| None, |
| ) |
| } else { |
| ( |
| brace_pos == BracePos::ForceSameLine |
| || (result.contains('\n') && brace_style == BraceStyle::PreferSameLine |
| || brace_style != BraceStyle::AlwaysNextLine) |
| || trimmed_last_line_width(&result) == 1, |
| rewrite_missing_comment( |
| mk_sp( |
| span_end_before_where, |
| if brace_pos == BracePos::None { |
| span.hi() |
| } else { |
| context.snippet_provider.span_before_last(span, "{") |
| }, |
| ), |
| shape, |
| context, |
| ), |
| ) |
| }; |
| // add missing comments |
| let missed_line_comments = missed_comments |
| .filter(|missed_comments| !missed_comments.is_empty()) |
| .map_or(false, |missed_comments| { |
| let is_block = is_last_comment_block(&missed_comments); |
| let sep = if is_block { " " } else { "\n" }; |
| result.push_str(sep); |
| result.push_str(&missed_comments); |
| !is_block |
| }); |
| if brace_pos == BracePos::None { |
| return Some(result); |
| } |
| let total_used_width = last_line_used_width(&result, used_width); |
| let remaining_budget = context.budget(total_used_width); |
| // If the same line brace if forced, it indicates that we are rewriting an item with empty body, |
| // and hence we take the closer into account as well for one line budget. |
| // We assume that the closer has the same length as the opener. |
| let overhead = if brace_pos == BracePos::ForceSameLine { |
| // 3 = ` {}` |
| 3 |
| } else { |
| // 2 = ` {` |
| 2 |
| }; |
| let forbid_same_line_brace = missed_line_comments || overhead > remaining_budget; |
| if !forbid_same_line_brace && same_line_brace { |
| result.push(' '); |
| } else { |
| result.push('\n'); |
| result.push_str(&offset.block_only().to_string(context.config)); |
| } |
| result.push('{'); |
| |
| Some(result) |
| } |
| |
| impl Rewrite for ast::ForeignItem { |
| fn rewrite(&self, context: &RewriteContext<'_>, shape: Shape) -> Option<String> { |
| let attrs_str = self.attrs.rewrite(context, shape)?; |
| // Drop semicolon or it will be interpreted as comment. |
| // FIXME: this may be a faulty span from libsyntax. |
| let span = mk_sp(self.span.lo(), self.span.hi() - BytePos(1)); |
| |
| let item_str = match self.kind { |
| ast::ForeignItemKind::Fn(ref fn_kind) => { |
| let ast::Fn { |
| defaultness, |
| ref sig, |
| ref generics, |
| ref body, |
| } = **fn_kind; |
| if let Some(ref body) = body { |
| let mut visitor = FmtVisitor::from_context(context); |
| visitor.block_indent = shape.indent; |
| visitor.last_pos = self.span.lo(); |
| let inner_attrs = inner_attributes(&self.attrs); |
| let fn_ctxt = visit::FnCtxt::Foreign; |
| visitor.visit_fn( |
| visit::FnKind::Fn( |
| fn_ctxt, |
| self.ident, |
| sig, |
| &self.vis, |
| generics, |
| Some(body), |
| ), |
| &sig.decl, |
| self.span, |
| defaultness, |
| Some(&inner_attrs), |
| ); |
| Some(visitor.buffer.to_owned()) |
| } else { |
| rewrite_fn_base( |
| context, |
| shape.indent, |
| self.ident, |
| &FnSig::from_method_sig(sig, generics, &self.vis), |
| span, |
| FnBraceStyle::None, |
| ) |
| .map(|(s, _, _)| format!("{};", s)) |
| } |
| } |
| ast::ForeignItemKind::Static(ref ty, mutability, _) => { |
| // FIXME(#21): we're dropping potential comments in between the |
| // function kw here. |
| let vis = format_visibility(context, &self.vis); |
| let mut_str = format_mutability(mutability); |
| let prefix = format!( |
| "{}static {}{}:", |
| vis, |
| mut_str, |
| rewrite_ident(context, self.ident) |
| ); |
| // 1 = ; |
| rewrite_assign_rhs( |
| context, |
| prefix, |
| &**ty, |
| &RhsAssignKind::Ty, |
| shape.sub_width(1)?, |
| ) |
| .map(|s| s + ";") |
| } |
| ast::ForeignItemKind::TyAlias(ref ty_alias) => { |
| let (kind, span) = (&ItemVisitorKind::ForeignItem(self), self.span); |
| rewrite_type_alias(ty_alias, context, shape.indent, kind, span) |
| } |
| ast::ForeignItemKind::MacCall(ref mac) => { |
| rewrite_macro(mac, None, context, shape, MacroPosition::Item) |
| } |
| }?; |
| |
| let missing_span = if self.attrs.is_empty() { |
| mk_sp(self.span.lo(), self.span.lo()) |
| } else { |
| mk_sp(self.attrs[self.attrs.len() - 1].span.hi(), self.span.lo()) |
| }; |
| combine_strs_with_missing_comments( |
| context, |
| &attrs_str, |
| &item_str, |
| missing_span, |
| shape, |
| false, |
| ) |
| } |
| } |
| |
| /// Rewrite the attributes of an item. |
| fn rewrite_attrs( |
| context: &RewriteContext<'_>, |
| item: &ast::Item, |
| item_str: &str, |
| shape: Shape, |
| ) -> Option<String> { |
| let attrs = filter_inline_attrs(&item.attrs, item.span()); |
| let attrs_str = attrs.rewrite(context, shape)?; |
| |
| let missed_span = if attrs.is_empty() { |
| mk_sp(item.span.lo(), item.span.lo()) |
| } else { |
| mk_sp(attrs[attrs.len() - 1].span.hi(), item.span.lo()) |
| }; |
| |
| let allow_extend = if attrs.len() == 1 { |
| let line_len = attrs_str.len() + 1 + item_str.len(); |
| !attrs.first().unwrap().is_doc_comment() |
| && context.config.inline_attribute_width() >= line_len |
| } else { |
| false |
| }; |
| |
| combine_strs_with_missing_comments( |
| context, |
| &attrs_str, |
| item_str, |
| missed_span, |
| shape, |
| allow_extend, |
| ) |
| } |
| |
| /// Rewrite an inline mod. |
| /// The given shape is used to format the mod's attributes. |
| pub(crate) fn rewrite_mod( |
| context: &RewriteContext<'_>, |
| item: &ast::Item, |
| attrs_shape: Shape, |
| ) -> Option<String> { |
| let mut result = String::with_capacity(32); |
| result.push_str(&*format_visibility(context, &item.vis)); |
| result.push_str("mod "); |
| result.push_str(rewrite_ident(context, item.ident)); |
| result.push(';'); |
| rewrite_attrs(context, item, &result, attrs_shape) |
| } |
| |
| /// Rewrite `extern crate foo;`. |
| /// The given shape is used to format the extern crate's attributes. |
| pub(crate) fn rewrite_extern_crate( |
| context: &RewriteContext<'_>, |
| item: &ast::Item, |
| attrs_shape: Shape, |
| ) -> Option<String> { |
| assert!(is_extern_crate(item)); |
| let new_str = context.snippet(item.span); |
| let item_str = if contains_comment(new_str) { |
| new_str.to_owned() |
| } else { |
| let no_whitespace = &new_str.split_whitespace().collect::<Vec<&str>>().join(" "); |
| String::from(&*Regex::new(r"\s;").unwrap().replace(no_whitespace, ";")) |
| }; |
| rewrite_attrs(context, item, &item_str, attrs_shape) |
| } |
| |
| /// Returns `true` for `mod foo;`, false for `mod foo { .. }`. |
| pub(crate) fn is_mod_decl(item: &ast::Item) -> bool { |
| !matches!( |
| item.kind, |
| ast::ItemKind::Mod(_, ast::ModKind::Loaded(_, ast::Inline::Yes, _)) |
| ) |
| } |
| |
| pub(crate) fn is_use_item(item: &ast::Item) -> bool { |
| matches!(item.kind, ast::ItemKind::Use(_)) |
| } |
| |
| pub(crate) fn is_extern_crate(item: &ast::Item) -> bool { |
| matches!(item.kind, ast::ItemKind::ExternCrate(..)) |
| } |